A composition used in combination with an electrohydrodynamic device capable of delivering an active ingredient to the aerodigestive system of the user. The composition comprises three or optionally four basic components: an active ingredient; a carrier material in which the active ingredient may be dissolved, suspended, or emulsified; an aerosol properties adjusting material which provides the composition with the physical characteristics required to create an aerosol cloud by electrostatic or electrohydrodynamic means; and optionally at least one excipient that further adjusts, preserves, stabilizes, or enhances the overall performance of the composition.

This invention relates to compositions for aerosolization and delivery to the user""s aerodigestive system by inhalation of the aerosolized composition, as well methods for making and using these compositions.
Administration of active ingredients directly to the aerodigestive system (i.e., the pulmonary system and/or digestive tract) of a patient by means of an inhaled aerosol may be preferable to other methods of drug delivery in certain circumstances. Delivery of drugs or other active ingredients directly to the patient""s lungs provides numerous advantages including: providing an extensive surface area for drug absorption, direct delivery of therapeutic agents to the disease site in the case of regional drug therapy, eliminating the possibility of drug degradation in the patient""s intestinal tract (a risk associated with oral administration), and eliminating the need for repeated subcutaneous injections. Furthermore, delivery of drugs to the pulmonary system by means of aerosol inhalation may be used to deliver drugs systemically, as well as for targeted local drug delivery for treatment of respiratory ailments such as lung cancer or asthma.
At the present time, inhalation therapy is a rapidly evolving technology. Numerous active ingredients are being developed with the expectation that effective delivery of and treatment with these agents will be possible by means of inhaled aerosols. Aerosolizing active ingredients requires a composition with certain characteristics and properties that make the composition compatible with the aerosolization process. The process of formulating particular active ingredients, such as drugs, with the appropriate carriers, such as organic solvents, can be particularly challenging. Therefore, there is a need for basic or general compositions which are compatible with a variety of active ingredients, a range of suitable carriers, and appropriate aerosol generating devices.
Important considerations in administering an aerosolized active ingredient to the lungs of a patient include the characteristics of both the composition containing the active ingredient, and the aerosol cloud that will ultimately be inhaled by the patient or user. The composition must be a suitable carrier for the active ingredient, the active ingredient must be stable for a period of time in the composition, the composition must be consistently sprayable through an aerosol-generating device, and the composition must be well-tolerated by the user. Furthermore, the aerosol-generating device itself must effectively and consistently convert the formula into an aerosol cloud with certain desired properties. For example, an aerosol-generating device should not deliver a high velocity aerosol which makes it difficult for the user to inhale aerosol particles. Preferred aerosol characteristics also include an aerosol cloud composed of particles that are roughly uniform in size. An aerosol cloud composed of uniform particles of a predetermined size provides the most efficient and effective delivery of the therapeutic composition to the patient or user because the dosage that the patient receives can be more precisely controlled (i.e., uniform particle size equals more precise delivery and dosage). Therefore, for maximum effectiveness of both drug and aerosol device, consistent generation of uniformly sized aerosol particles most occur each time the composition is aerosolized with a particular device.
Aerosol devices currently used in the clinical context include metered dose inhalers, dry powder inhalers, and nebulizers. Although effective at creating aerosols, these devices typically do not permit the device user to control either the particle size of the aerosol cloud to be inhaled, or the velocity of the aerosol delivered by the device. The particle size distribution of aerosols generated with these devices is usually too broad or too varied to effectively and consistently deliver the composition to the deep lungs of the user. As a consequence, pulmonary administration of a active ingredient may be less than optimal when using metered dose inhalers, dry powder inhalers, or nebulizers due to deposition of the composition in the mouth or throat of the user or due to exhalation of the composition by the user.
U.S. Pat. No. 4,829,996 to Noakes et al., and U.S. Pat. No. 5,707,352 to Sekins et al. both disclose formulations suitable for use with aerosol devices; however, these devices and formulas are suboptimal when compared with the performance of electohydrodynamic (EHD) aerosol systems. EHD aerosol generators are capable of generating aerosols in which particle size, aerosol velocity, and the resultant deposition patterns can be more precisely controlled. EHD aerosol generators, therefore, are ideal devices for use with therapeutic compositions that are to be delivered to the patient""s pulmonary system by inhalation. Thus, there is a need for therapeutic compositions that are compatible with both a variety of active ingredients as well as electrostatic and EHD aerosol generating devices.
The present invention includes general compositions capable of: being aerosolized; inhaled by the user; delivering a predetermined dosage of a active ingredient to the lungs of the user; and which are optimized for use with an electrohydrodynamic aerosol generator. These compositions may contain two or more basic components which may be present in a variety of combinations, concentrations, and ratios to one another.
In a preferred embodiment of the present invention, the general composition comprises four basic, or fundamental, components. The first component is a active ingredient; examples of which include drugs, vaccines, and proteins. The second component of the therapeutic composition is a carrier material in which the active ingredient may be dissolved, suspended, or emulsified; examples of which include water or alcohol. The third component of the therapeutic composition is an aerosol properties adjusting material, which adjusts the physical properties of the liquid composition to be within ranges desired for aerosolization with an electrostatic or electrohydrodynamic device. In some embodiments of the invention the carrier material may act as the property adjusting material so as to bring the composition within the desired ranges of physical or chemical properties. In such cases no additional third basic component is required. The fourth optional component of the basic composition is at least one excipient that individually or in combination with other excipients preserves, stabilizes, or enhances the overall performance of the therapeutic composition. Examples of suitable excipients include ionic materials, surfactants, and antimicrobial agents.
Therefore, it is an object of the present invention is to provide a general base composition that includes a suitable carrier for a variety of active ingredients, and in which the active ingredients will be stable for an extended period of time.
Another object of the present invention is to provide a base composition which is compatible with electrostatic or electrohydrodynamic aerosol generating devices.
A further object of the present invention is to provide a liquid composition with a commercially reasonable shelf-life.
Further objects, advantages, and novel aspects of this invention will become apparent from a consideration of the subsequent detailed description.
Broadly, the present invention provides compositions, and methods for making and using compositions, which have certain preferred characteristics and properties required for generating aerosols also having particular preferred characteristics. In a preferred embodiment of the present invention, the compositions are aerosolized with an electrostatic or electrohydrodynamic (EHD) aerosol generating device. A typical embodiment of this invention includes a liquid composition having predetermined physical and chemical properties which facilitate aerosolization of the composition with an EHD aerosol device. This liquid composition typically includes three or four basic components which are (i) an active ingredient; (ii) a liquid carrier for the active ingredient; (iii) an aerosol properties adjusting material; and optionally (iv) at least one excipient. The combination of these components provides a therapeutic composition having enhanced properties for delivery to a user by means of generating an inhalable aerosol.
Electrohydrodynamic Aerosols
The therapeutic compositions of this invention must be compatible with an aerosol-generating device so that an aerosol cloud with certain preferred properties and characteristics is reproduced each time the device is used. Aerosols having uniformly-sized particles and uniform distribution patterns are desirable over aerosols that do not possess these characteristics because they exhibit more desirable deposition properties within the aerodigestive tract of the user (i.e., they have a higher respirable fraction). When used with compatible compositions, EHD aerosol generating devices can be adjusted to create substantially monomodal aerosols having particles more uniform in size than aerosols generated by other devices or methods.
Typical EHD devices include a spray nozzle in fluid communication with a source of liquid to be aerosolized, at least one discharge electrode, a first voltage source for maintaining the spray nozzle at a negative (or positive) potential relative to the potential of the discharge electrode, and a second voltage source for maintaining the discharge electrode at a positive (or negative) potential relative to the potential of the spray nozzle. Most EHD devices create aerosols by causing a liquid to form droplets that enter a region of high electric field strength. The electric field then imparts a net electric charge to these droplets, and this net electric charge tends to remain on the surface of the droplet. The repelling force of the charge on the surface of the droplet balances against the surface tension of the liquid in the droplet, thereby causing the droplet to form a cone-like structure known as a Taylor Cone. In the tip of this cone-like structure, the electric force exerted on the surface of the droplet overcomes the surface tension of the liquid, thereby generating a stream of liquid that disperses into a many smaller droplets of roughly the same size. These smaller droplets form a mist which constitutes the aerosol cloud that the user ultimately inhales.
Physical Characteristics of Liquid Composition
Liquid compositions that are compatible with EHD aerosol generating devices must have characteristics and properties that fall within certain parameters for the aerosol cloud to have the desired properties. In a preferred embodiment of the present invention, the most relevant physical characteristics of the composition include surface tension, electrical resistivity, and electrical permittivity (dielectric constant). Additionally, viscosity of the composition can also be of importance in preparing liquid therapeutic compositions for use with electrostatic or EHD devices.
Surface tension is a property possessed by liquid surfaces whereby these surfaces behave as if covered by a thin elastic membrane in a state of tension. Surface tension is a measure of the energy needed to increase the surface area of the liquid; therefore, liquids with a lower surface tension will aerosolize more easily than liquids with higher surface tension. Surface tension is measured by the force acting normally across unit length in the surface. The phenomenon of surface tension is due to unbalanced molecular cohesive forces near the surface of a liquid. In a broad embodiment of the present invention, the surface tension of the composition is typically within the range of about 10 to 72 milliNewtons/meter. In another embodiment of the present invention, the surface tension of the composition is typically within the range of about 15 to 45 milliNewtons/meter. In a preferred embodiment of the present invention, the surface tension of the composition is typically within the range of about 20 to 35 milliNewtons/meter.
Electrical conductivity is the ability of a solution to transport electrical charge. The inverse of electrical conductivity is electrical resistivity. Thus, electrical resistivity is a measure of the ability of a material to resist the transport of electrical current, and is a property of a conductor, which gives the resistance in terms of the conductor""s dimensions. Liquid compositions with resistivity values of 10 to 100,000 ohm-meters can be aerosolized using EHD aerosol devices, provided that other relevant physical properties are within optimal operating parameters. Thus, in a broad embodiment of the present invention, the electrical resistivity of the composition is typically within the range of about 10 to 100,000 ohm-meters. In another embodiment of the present invention, the electrical resistivity of the composition is typically within the range of about 50 to 10,000 ohm-meters. In a preferred embodiment of the present invention, the electrical resistivity of the liquid composition is typically within the is range of about 200 to 2000 ohm-meters.
Electrical permittivity is a measure of the polarizibility of a liquid, and is relevant in electrostatic spraying processes as it describes the increase in electrical field strength where a fluid is present. To aerosolize solvents with high permittivity (e.g., water), a higher electrical field strength (voltage) is required. The permittivity of a liquid composition is not significantly affected by the addition of a small amount (less than 5%) of non-ionic excipients or solvents. In a broad embodiment of the present invention, the electrical permittivity of the composition is typically within the range of about 5 to 500. In another embodiment of the present invention, the electrical permittivity is typically within the range of about 10 to 150. In a preferred embodiment of the present invention, the electrical permittivity of the composition is typically within the range of about 15 to 50. Electrical permittivity is a dimensionless value denoting the ration of the electrical permittivity of a liquid or material to that of a vacuum.
Viscosity is the measure of the resistance to fluid flow; thus solutions that flow easily generally have lower viscosity. The viscosity of a liquid composition is not affected significantly by the addition of small amounts of drug to the composition. However, the addition of certain suspending agents or very high concentrations of drugs can increase the viscosity of the liquid composition. Viscosity may not be a key solvent parameter in aerosolization of the present invention, but it does affect particle size distribution. Highly viscous materials tend to form aerosols with more disperse or bimodal distributions, and with particle sizes larger than desired for respirable aerosols.
Liquid compositions having physical properties within the optimal parameters disclosed above will aerosolize when used with most EHD devices. In the present invention, controlling the voltage delivered to the system to create the region of high electric field strength also controls the particle size of the aerosol cloud generated by an EHD device. In a broad embodiment of the present invention directed toward inhalation, the size of respirable aerosol particles is typically about 0.1 to 10.0 micrometers. Aerosol particles at the lower end of this range are required for delivery of the liquid composition to the deep lung, while aerosol particles at the upper end of this range are required for delivery of the composition to the proximal respiratory tract. For deposition of the composition in the central and peripheral areas of the lung, the preferred size of the aerosol particles is about 1.0 to 6.0 micrometers.
Active Ingredient
To benefit the user, the aerosolized liquid composition of the present invention contains at least one active ingredient at a concentration permitting delivery of the desired dosage to the patient. The number and types of active ingredients suitable for delivery to a patient by means of an inhaled aerosol varies widely and includes numerous options. A preferred embodiment of the present invention typically includes at least one active ingredient which may be any of the following: small molecule and synthetic drugs such as sodium cromoglycate, albuterol sulfate, and triamcinolone acetonide; chemo-therapeutic or chemopreventive agents such as paclitaxel and doxorubicin; vaccines; nucleic acids, including DNA and RNA vectors and vaccines; aptamers, proteins such as insulin; gene therapy agents for treating diseases such as cystic fibrosis; enzymes, hormones; antibodies; vitamins; peptides and polypeptides; oligonucleotides; cells; antigens; allergens; pulmonary surfactant and other surfactants (including synthetic surfactants); anti-infectious agents including antimicrobials, antibiotics, antifungals and antivirals; and pain management drugs such as narcotics.
Preferred initial concentrations of active ingredients in the composition are determined by the required effective dosage of each active ingredient, as well as the efficiency of the pulmonary delivery of the inhaled aerosol. Delivery efficiency and drug efficacy is typically impacted by the selected deposition site within the user""s lung.
Carrier Material
In the present invention, the composition to be aerosolized also provides a carrier in which the active ingredient may be dissolved, suspended or emulsified. A variety of solvents or emulsifying agents are suitable for this purpose. In a typical embodiment of the present invention, either water or ethanol (depending on the solubility characteristics of the active ingredient) is used as the solvent in which the active ingredient may be dissolved or suspended. In a preferred embodiment, the carrier (solvent) fraction of the composition may represent 5 to 95% of the total volume of the composition. In other embodiments, the fraction of the composition represented by the carrier varies depending on the solubility or insolubility of the active ingredient. For example, if a active ingredient is highly soluble in the carrier (e.g. water), then the carrier fraction of the total composition may be as low as about 5% to 10%. If an active ingredient is only moderately soluble in water, a larger fraction of water may be required to completely dissolve or sufficiently suspend the active ingredient.
The pH of desired solvent, as well as the pH of the entire composition, may impact the solubility and stability of the active ingredient. Although pH requirements are likely to differ among specific compositions depending on the active ingredient being used, pH ranges useful in the present invention for the liquid carrier may be in the range of pH about 2 to 9. Preferably, a pH range of about 3 to 8 is used, and most preferably a pH range of about 5 to 8 is used.
In a preferred embodiment of the present invention, the solvents selected as carriers are chosen for use as carriers based both on compatibility with certain active ingredients and on their compatibility with EHD devices, and typically include water or ethanol. In an alternative embodiment, phospholipids or pulmonary surfactant is used as a carrier. In still another embodiment, other alcohols such as isopropanol are employed as carriers. In other embodiments of the present invention, perfluoronated compounds such as perfluorooctanol and perfluorodecalin are substituted for some or all of the water or ethanol as the carrier material. Such perfluoronated compounds are useful as alternative carriers for drugs soluble in perfluoronated carriers, micro-suspended medicaments or emulsified mixtures of such pharmaceutical products in water.
Aerosol Properties Adjusting Material
Certain physical properties of a liquid composition are critical in enhancing the effectiveness of aerosolization of the composition with an electrostactic or EHD device. Therefore, in the present invention, an aerosol properties adjusting material that provides the desired physical characteristics to the composition represents another possible fraction of the total volume of the liquid composition. In a broad embodiment of this invention, the physical properties of the liquid composition typically comprise: (i) a surface tension of about 10 to 72 milliNewtons/meter; (ii) an electrical resistivity of about 5 to 100,000 ohm-meters; and (iii) and an electrical permittivity of about 5 to 500. In some embodiments, it may be possible to achieve a liquid composition with physical properties falling within these parameters by simply combining the active ingredient and the carrier material. However, if the combination of the active ingredient and the carrier material does not produce a liquid composition having physical properties falling within these parameters, the addition of the aerosol properties adjusting material will bring the composition within the required parameters.
In a preferred embodiment of the invention, the aerosol properties adjusting material is present as about a 5 to 90% fraction of the total volume of the composition. The volume of the aerosol properties adjusting material fraction will vary depending on the volume of the carrier that is required. For example, if the carrier represents 20% of the total volume of the composition, the aerosol properties adjusting material could represent the remaining 80% of the total volume. The 20/80 volume ratio can apply even with the active ingredient present because the active ingredient is dissolved in the carrier and/or aerosol property adjusting material. In some instances, the carrier itself may serve as the aerosol properties adjusting material.
In a preferred embodiment of the present invention, the aerosol properties adjusting material may be at least one of the following materials or their derivatives; ethanol or other alcohols; propylene glycol; polyethylene glycol; glycerol; oleic acid; medium chain triglycerides; fatty acids; soybean oil; olive oil; phospholipids, and perfluorocarbons. Combinations of these materials is advantageous in some embodiments. For example, the use of ethanol alone may create an aerosol, but the particle size of the aerosol may be below the preferred range. By combining ethanol and polyethylene glycol in a predetermined ratio to one another, the preferred particle size can be achieved. In one embodiment of the present invention, the aerosol enhancing component comprises 80% ethanol and 10% polyethylene glycol for a fraction representing 90% of the total volume of the liquid composition.
Excipient
As discussed, there are acceptable ranges of solvent parameters that permit a liquid composition to be aerosolized by the electrohydrodynamic process. Due to the characteristics of certain active ingredients (e.g., ionic, solubility limits, etc.) it may be difficult to formulate a drug at desired concentrations in an appropriate carrier solvent while remaining within the required solvent parameter values. The addition of an excipient can alter a solvent parameter and bring the composition back within the optimal ranges. Addition of an excipient is necessary only in embodiments of the present invention in which the combined active ingredient, carrier material, and aerosol properties adjusting material do not yield an aerosol with all of the desired characteristics.
Various embodiment of the present invention include at least one excipient or a combination of excipients. A broad definition of an excipient is anything in a composition other than an active ingredient. In the more narrow context of the present invention, an excipient is added for a variety of purposes including: stabilization of the liquid composition; facilitating control of aerosol particle size; increasing the solubility of the active ingredient in the composition; and lowering the surface tension of the liquid.
Once solubilized, suspended or emulsified, the active ingredient must also be stable in the carrier itself, and stable in the final composition. Stability requires that the active ingredient not lose activity prior to aerosolization (i.e. retains a reasonable shelf-life), and that the active ingredient not lose activity or degrade significantly as a result of the process of aerosolization. Furthermore, the complete composition must itself be stable over time. In various embodiments, stability issues can be addressed by the addition of a stabilizing excipient to the composition.
In a preferred embodiment of the present invention, at least one of the following excipients is added to increase physical stability of the composition: oils, glycerides, polysorbates, celluloses lecithin, polyvinyl pyrrolidone, polyethyl glycol, saccharide gums, and alginates; while ascorbic acid, citric acid, cyclodextrin, tocopherols or other antioxidants are added to increase chemical stability. In another embodiment of the present invention, chelating or complexing agents such as citric acid, cyclodextrins, and ethylenediaminetetracetic acid may be added to stabilize drug compositions and to increase the solubility of the active ingredient in the composition.
In other embodiments, antioxidants such as ascorbic acid and ascorbic acid esters, Vitamin E, tocopherols, butylated hydroxyanisole, and butylated hydroxytoluene are added to reduce degradation of a drug composition caused by oxidation.
An excipient may also be added as a preservative to maintain the microbial integrity of the therapeutic composition. In one embodiment of the present invention, at least one of the following excipients is added to preserve compositions against microbial contamination or attack: benzalkonium chlorides, phenol, parabens, or any other acceptable antimicrobial or antifungal agent.
By further adjusting physical properties, the addition of excipients may also enhance the overall performance of the composition in terms of the quality of aerosol produced by an EHD device. In one embodiment of the present invention an ionic compound (e.g., salt) such as sodium chloride, sodium acetate, benzalkonium chloride, or lecithin, is added to further adjust electrical resistivity, thereby facilitating control of aerosol particle size.
In another embodiment of the present invention, surfactants such as lecithin, polysorbates, poloaxamers, sorbitan esters, glycerides, ethoxylated alcohols, ethoxylated phenols, and ethylene oxide-propylene oxide copolymers are added to lower the surface tension of the liquid. In a preferred embodiment, non-ionic ethoxlyated decyl alcohol (Desonic DA-4) having hydrophilic-lipophilic balance (HLB) of about 10.5 is added to highly aqueous compositions to enhance the dispersion characteristics of the composition. The present invention contemplates the use of both pulmonary surfactant and other natural or synthetic surfactants.
In another embodiment of the present invention, suspending agents such as celluloses, polyvinyl pyrrolidone (povidone or PVP), polyvinyl alcohol (PVA), triglycerides, ethoxylated oils, polyethyl glycol, saccharide gums, and alginates may be added to facilitate suspension of particles, or creation of an emulsion, in a liquid composition.
In still another embodiment of the present invention, adjuvants such as clove oil, citric acid, caffeine, vaccine adjuvants such as alum, polymers, macromolecules, and oligonucleotides are added to provide enhanced synergistic efficacy effect between the active ingredient and the excipient.
Excipients may also be added to enhance or increase the patient""s ability to receive the aerosolized composition. For example, in one embodiment of the present invention, sugars, including sucrose, trehalose, and mannitol, are added either to stabilize compositions containing proteins, or to serve as sweeteners to improve the taste of the composition. In other embodiments, flavoring agents such as sugars, oils, citric acid, menthol, and camphor are added to improve the flavor of a composition.

Compositions for aerosolization and inhalation


The present invention is directed to polymer compositions with flame retardant properties that are made from a polymer blended using a defined process with a smectite clay that has been reacted with a specified mixture of organic materials.

1. Field of the Invention
The present invention is directed to polymer compositions with flame retardant properties that are made from a polymer blended using a defined process with a smectite clay that has been reacted with a specified mixture of organic materials.
The inventive compositions have the property that when the organically modified clay is added to the polymer, a composite results which has flame-retardant properties.
This invention covers improved polymer compositions with increased char yield and fire retardancy. The use of organoclay is a new, environmentally-benign approach to improve the fire retardance of these polymers. Such polymers will find use, for example, as architectural and construction materials such as interior panels, home sidings, and roofing pads and shingles, automotive parts particularly for car interiors, and in ship and military uses where fire retardancy is required.
2. Background of the Invention
It has long been a goal when using plastic materials to render them resistant to burning. Building codes and other government rules issued by regulatory bodies often require that plastic materials used as structural members or other useful articles pass a series of precise tests to insure that they will not accelerate a fire. In the past, many flame retardant polymer formulations have been developed. These include several classes of materials such as halogenated additives, char chemical producers, and chemical water generators. Each of these prior art materials has its particular strengths and weaknesses as a fire retardant.
The use of synthetic polymers has grown dramatically over the last three decades, as have the research efforts of scientists on controlling polymer flammability. Research and development to that end has focused primarily on fire retardant additives. One way to improve fire resistance has relied on the introduction of aromatic rings into the polymer structure; an increase in the aromaticity yields higher char residues that normally correlate with higher oxygen index and lower flammability. The high cost of these specialized materials and the specialized processing techniques required have limited their use and makes the search for an effective additive even more focused.
The effectiveness of fire retardant fillers has also been limited because the large amounts required for effective performance make processing difficult and the additives often negatively affect some properties of the final polymer compositions. High loadings of fillers can cause problems in the plastic such as loss of strength and flexibility, and discoloration. The relatively high loading of fire retardants needed in some plastics to achieve sufficient reduction in flame spread can also be very expensive.
Particularly disadvantaged prior art materials used as fire retardants are additives containing halogens. Problems associated with these materials include high costs, high use levels, and potential environmental problems. Brominated aromatic compounds, for example, have been widely used as fire retardants for polyolefins and other thermoplastics. In addition to the poor economics of using these materials, other concerns include suspected negative environmental impact and their well-established tendency to generate corrosive by-products during processing or when exposed to fire.
These concerns have established the need for fire retardant systems for polymers with reduced halogen content. It is thus the object of the instant invention to provide a flame retardant blend comprising reduced levels of halogenated compounds.
3. Description of the Prior Art
In the past organoclays have been blended with polymers as fire retardants in circumstances where an additional fire retardant additive was used. Several general articles on polymer-clay blends have included in their discussion a section about fire retardancyxe2x80x94see for example Miller, B.; Plastics World, No.10, October 1997, pp. 36-38.
An early patent by Berk Ltd., U.S. Pat. No. 3,516,959, describes an organophilic clay used with at least one additional flame retardant. A variety of thermoplastic polymer composites is described. No attempt is made to show the effect of an organoclay by itself on flame retardancy nor how the degree of dispersion would influence this.
Several specific patents discuss clay-polymer composites in the context of fire retardance. U.S. Pat. No. 4,472,538 discloses clay treated with a chlorosilane to initiate polymerization with an adsorbed monomer to give a composite with excellent flame retardance. The use of silane initiator gives a polymer chemically bound to the clay surface. A second object of the patent is to create a uniformly dispersed polymer-clay composite. No flame testing was done to indicate the degree of flame retardance nor are there comparisons of differing levels of dispersion.
U.S. Pat. No. 5,854,327 by Bridgestone/Firestone discloses a roofing membrane that is made flame retardant by a complex mixture of ingredients. The clay component is treated to make it reactive with the EPDM rubber matrix but no specific flame-retardant properties are associated with the clay.
A General Electric patent, European Patent No. 899,301 A1, describes a non-halogenated flame retardant resin-molding polyester composition that contains organoclay, polysiloxane, and compounds of boron and phosphorus.
A number of authors have made statements in the literature that to achieve the best properties from a smectite clay-polymer composite, it is necessary to achieve the best dispersion possible. This can be described as completely exfoliating the smectite clay into individual platelets separated by the polymer matrix. It has been surmised that it is optimum that the platelets should be in insufficient contact to be chemically associated with each other. It is the fully dispersed state that is frequently held up as the ideal for all developments in the smectite clay/organoclay composite areas.
Several papers and patents explicitly mention the critical need for platelet interlayer distances to be greater than 70 xc3x85 to have complete exfoliation/delamination. These papers include: Giannelis, E. P.; Polymer Layered Silicate Nanocomposites. Advanced Materials 8, No. 1, pp. 29-35 (1996); and Kishnamoorti, R.; Vaia, R. A.; Giannelis, E. P.; Structure and Dynamics of Polymer Layered Silicated Nancomposites, Chemistry of Materials 8, No. 8, pp.1728, (1996).
Several prior art patents go into significant detail on the differences between incompletely exfoliated states and the benefits of fully delaminated clay-polymer composites. A Toyota patent, U.S. Pat. No. 4,739,007, asserts that the best improvements in mechanical properties are observed in composites with platelet spacings greater than or equal to 100 xc3x85. It is clear from the prior literature that fully exfoliated clay-polymer systems have been the goal of researchers working in the field.
It is noted that several papers on flame-retardant polymer compositions not using organoclays show evidence that less than full exfoliation has benefits. For example, Nyden, M. R. and Gilman, J. W.; Molecular Dynamics Simulations of the Thermal Degradation of Nano-Confined Polypropylene, Computational and Theoretical Polymer Science, Vol. 7, No. 3/4, pp. 191-8 (1997), shows polypropylene confined by graphite. A minimum in the burning mass loss rate was calculated for polypropylene confined between the graphite sheets at 30 xc3x85. The author did not show any experimental evidence to support the theoretical conclusions.
A United States patent based on a Japanese invention describes polymeric compositions using calcium carbonate and other materials including kaolin clays other than smectites as fire retardant additives to polymersxe2x80x94see U.S. Pat. No. 5,025,057. U.S. Pat. No. 5,091,462, also based on a Japanese invention, shows the addition of an inorganic filler to crystalline polypropylene to improve the heat resistance of the polypropylene in the form of a four or five ingredient resin composition. The inorganic filler can be a polyamide partially modified with hectorite.
Organically modified clays, also called organoclays, have been used for many years as rheological additives for solvent based systems. They are usually produced by making a water dispersion of a phyllosilicate clay, usually a bentonite or hectorite clay, and adding to it a quaternary ammonium salt of a long chain fatty acid to produce an organically modified clay by cation exchange reaction and adsorption. The reaction causes the organoclay to coagulate from the water dispersion which allows for its isolation by filtration and washing.
For example, Rheox, Inc. has issued patents describing organoclay compositions useful as rheological additives which comprise the reaction product of smectite clay, quaternary ammonium compounds and in addition in some embodiments certain organic anions, wherein a quaternary-organic anion complex is reacted with the smectite clay. These patents include representative U.S. Pat. Nos. 4,412,018, 4,434,075, and 4,517,112 (descriptions herein incorporated by reference) and are described to include a large variety of organic cationic compounds, in combination with one or more organic anion compounds. These patents do not describe the use of these organoclays to provide thermoset or thermoplastic polymers with fire retardant properties.
A recently allowed United States patent application by the assignee hereof (U.S. patent application Ser. No. 09/064,216, filed Apr. 22, 1998) describes a hybrid organoclay system that gives improved dispersion in a polyester resin over conventional organoclays or simple intercalates when forming a nanocomposite. See also pending U.S. patent application Ser. No. 09/317,963 filed by assignee hereto entitled Smectite Clay/Organic Chemical/Polymer Compositions Useful as Nanocomposites.
It is an object of the invention to provide a modified clay/polymer composition using a thermoset or thermoplastic polymer and a smectite clay modified with organic chemicals, i.e. an organoclay. The organoclay used is dispersed into thermoset or thermoplastic polymers to form a composition with fire retardancy.
It is a specific object of the invention that the organoclay can be made inexpensively and the polymer composition in some circumstances needs no other material except the organoclay to possess acceptable fire retarding properties.
The present invention is of a composition comprising a polymer system and a smectite clay modified with an organic chemical composition. The modified clay is an organic chemical/clay mixture prepared by the reaction of a smectite clay and one or more quaternary ammonium compounds, and/or optionally one or more organic materials. The organoclay is then blended into a polymer matrix to give the invention composition. The behavior of the resultant plastic/organoclay product is qualitatively different in fire retardant properties from that exhibited by the plastic, polymer, or resin by itself.
This invention provides a practical way to disperse organoclays based on smectite clays into polymers without resorting to expensive processes or special resin materials to insure compatibility with the polymer matrix. The resulting compositions have fire retardant properties.
In one important embodiment, we have determined that a substantial gain of fire retardancy occurs if a clay-polymer composite is produced in a way that causes the organoclay to substantially but not completely delaminate in the polymer. Testing in a thermoplastic polyolefin elastomer (TPO) has shown a strong, correlation between degree of delamination (exfoliation) of the organoclay and flame testing. By delaminate it is meant dispersed or exfoliated.
In one aspect, the present invention provides a polymer composition that comprises: (a) one or more smectite clays, modified with (1) one or more quaternary ammonium compounds at between about 50 to 150% of its cation exchange capacity, and also in some embodiments with (2) one or more defined organic materials to form an organoclay composition and
(b) one or more polymer resins;
whereby the organoclay composition is mixed or blended into the polymer resin in a manner so that the organoclay is not completely delaminated.
Further advantages and features of the invention, as well as the scope, nature and utilization of the invention, will become apparent to those of ordinary skill in the art from the description of the preferred embodiment of the invention set forth below.
The clay and polymer compositions of this invention may be made using a variety of materials and by a variety of methods disclosed hereafter, or which will appear obvious when the disclosure of this patent occurs. Applicants do not intend to limit the materials or methods of manufacture or use of such additives by the following descriptions.
This invention is in one main embodiment, synthetic polymer compositions, particularly thermoset or thermoplastic compostions, which have flame-retardant properties.
The synthetic thermoset or thermoplastic polymers with which this invention is concerned (hereinafter referred to, for convenience, simply as xe2x80x9cthermoset or thermoplastic polymersxe2x80x9d) are those which are combustible and, in addition to being combustible, which melt or drip when heated beyond their softening point.
While the flammability of these polymers can be substantially reduced by the incorporation therein of one or more flame retardants, they represent (with the use of present additives) a considerable fire hazard. When heated beyond their softening point, they will melt and hot material will drip or flow onto surrounding areas and increase the risk of ignition of surrounding materials. This can be true even when the polymer itself does not burn. Examples of thermoplastic polymers are polystyrene, polyethylene, and polyamides, such as nylon. Examples of thermoset polymers are urea-formaldehyde polymers, epoxies, and melamine-formaldehyde polymers.
The tendency of thermoplastic polymers to melt and drip when heated to temperatures above their softening points can be substantially reduced by incorporating into them a small proportion (that is, less than 10% based on the weight of the polymer) of the organically modified clay of this invention.
Synthetic polymers suitable for this invention include a wide variety of resins and plastic materials, both polar or non-polar. Such materials can include polyolefins such as polyethylenes, polypropylenes, polybutylenes, polymethylpentane, polyisoprenes, and copolymers thereof; copolymers of olefins and other monomers such as ethylene-vinyl acetate, ethylene acid copolymers, ethylene-vinyl alcohol, ethylene-ethyl acrylate, and ethylene-methyl acrylate. Ionomers are also useful and comprise metal salts of polyolefins copolymerized with acrylic acid.
Additional polymers are polyamides (nylons), polyphenylene ether, and polyamide-imide copolymers. Various polyesters are useful such as polyarylates, polybutylene terephthalate, and polyethylene terephthalate. Engineering resins such as polycarbonate, polyetherimide, polyetheretherketone, polyphenylene sulfide, and thermoplastic polyimides are suitable candidates. Polystyrene and copolymers such as ABS, SAN, ASA, and styrene-butadiene are appropriate. Also included are the sulfone based resins such as polysulfone, polyethersulfone, and polyarylsulfone. Elastomers are also candidates for the present invention and comprise a wide variety of useful materials including olefinic TPE""s, polyurethane TPE""s, and styrenic TPE""s. Chlorinated polymers such as PVC, and polyvinylidene dichloride can also be used. In addition, miscible or immiscible blends of the above polymers are useful for this invention.
The present invention accordingly comprises a polymer composition comprising a thermoset or thermoplastic polymer, and incorporated therein, an organoclay defined hereafter.
One important aspect of the invention is a clay and polymer composition comprising:
A reaction product obtained by the intercalation and reaction of (a) one or more smectite clays; (b) one or more quaternary ammonium compounds and/or (c) one or more organic materials; which is then dispersed in a manner not to be completely exfoliated into;
(d) one or more polymers.
Clays useful for element a) are smectite clays. Such clays are swellable layered clays which contain individual platelets. Useful swellable layered materials include phyllosilicates such as smectite clay minerals, e.g., montmorillonite, particularly sodium montmorillonite; bentonite; hectorite; saponite; stevensite; beidellite; and the like.
The clays used are typically smectite clays, particularly bentonite and hectorite, Smectite clays possess some structural characteristics similar to the befter-known minerals talc and mica. Their crystal structures consist of two-dimensional layers formed by fusing two silica tetrahedral sheets to an edge-shared dioctahedral or trioctahedral sheet of either alumina (for example bentonite) or magnesia (for example hectorite)xe2x80x94each of the different smectite clays having somewhat different structures. Stacking of these layers in nature in depths of hundreds or more is caused by ionic and weak Van der Waals forces. The area between the platelets is occupied by cations which balance the charge deficiency that is generated by isomorphous substitution (often called disharmonies) within the platelet lattices.
As used herein the term xe2x80x9cinterlayer spacingxe2x80x9d refers to the distance between the internal faces of adjacent smectite clay platelet layers, either in the dry state or as incorporated into a polymer. The interlayer spacing is measured by standard X-Ray Diffraction techniques.
Central to the instant invention is the degree of dispersion of the organoclay in the polymer. When the organoclay is dispersed in the polymer such that only a few polymer chains are between the clay platelets, the system is referred to as being substantially intercalated. When measured by X-Ray Diffraction such a material will display an interlayer spacing of approximately 15 to 60 xc3x85, depending on the polymer. The extreme of dispersion is exfoliation, and is defined as a state in which the clay particles are substantially or completely separated by the polymer matrix. Interlayer platelet spacings in an exfoliated system are typically greater than 70 xc3x85, and such systems are easily characterized by X-Ray Diffraction by the near or total absence of any reflection peaks from the organoclay. As defined above, the required state of dispersion for the organoclays of this invention consists of intercalation, or a mixture of intercalation and exfoliation, but not complete exfoliation.
The clays which may be used in the present invention are preferably smectite-type clays having a cationic exchange capacity of at least 50 milliequivalents per 100 grams of clay, 100% active clay basis, as determined by the well-known ammonium acetate or methylene blue methods. Preferred smectite materials are bentonite and hectorite clays having a negative charge on the layers ranging from about 0.15 to about 0.9 charges per formula unit and a commensurate number of exchangeable metal cations in the interlayer spaces.
Smectite-type clays are well known in the art and are commercially available from a variety of sources. Prior to use in the invention, the clays may preferably be converted to the sodium form if they are not already in this form. This may be conveniently carried out by preparing an aqueous clay slurry and passing the slurry through a bed of cation exchange resin in the sodium form. Alternatively, the clay can be mixed with water and a soluble sodium compound, such as sodium carbonate, sodium hydroxide, etc., and the mixture sheared, such as with a pugmill or extruder.
Representative smectite clays useful in accordance with the present invention are the following:
[(Al4xe2x88x92xMgx)Si8O20(OH)4xe2x88x92fFf]xR+
where 0.55 less than x less than 1.10, f less than 4 and R is selected from the group consisting of Na, Li, NH4, and mixtures thereof;
[(Al4xe2x88x92xMgx(Si8xe2x88x92yAly)O20(OH)4xe2x88x92fFf](x+y)R+
where 0 less than x less than 1.10, 0 less than y less than 1.10, 0.55 less than (x+y) less than 1.10, f less than 4 and R is selected from the group consisting of Na, Li, NH4, and mixtures thereof;
[(Mg6xe2x88x92xLix)Si8O20(OH)4xe2x88x92fFf]xR+
where 0.57 less than x less than 1.15, f less than 4 and R is selected from the group consisting of Na, Li, NH4, and mixtures thereof;
[(Mg6xe2x88x92yAly)Si8xe2x88x92xxe2x88x92yAlx+yO20(OH)4xe2x88x92fFf]xR+
where 0.58 less than x less than 1.18, 0 less than y less than 0.66, f less than 4 and R is selected from the group consisting of Na, Li, NH4, and mixtures thereof; and
[Mg6xe2x88x92xSi8O20(OH)4xe2x88x92fFf]2xR+
where 0.28 less than x less than 0.57, f=4 and R is selected from the group consisting of Na, Li, NH4, mixtures thereof.
[(Al4+y)(Si8xe2x88x92xxe2x88x92yAlx+y)O20(OH)4xe2x88x92fFf]xF+
where 0.55 less than x less than 1.10, 0 less than y less than 0.44, f less than 4 and R is selected from the group consisting of Na, Li, NH4, and mixtures thereof;
The preferred clays used in the present invention are bentonite and hectorite. Bentonite and its properties are described at length in the chapter entitled xe2x80x9cBentonite,xe2x80x9d in Carr, D., ed., Industrial Minerals and Rocks, 6th Edition, published by the Society For Mining, Metallurgy and Exploration, Colorado, 1994. A particularly preferred clay is hectorite.
It will be understood that both sheared and non-sheared forms of the above-listed smectite clays may be employed. In addition, the smectite clay employed can be either crude (containing gangue or non-clay material) or beneficiated (gangue removed). The ability to use crude clay in the smectite-type clay of this invention represents a substantial cost savings, since the clay beneficiation process and conversion to the sodium form do not have to be carried out.
Compound(s) (b) of the invention is one or more quaternary ammonium compounds. Particularly useful are quaternary ammonium compounds which include those having the formula:
wherein R1 comprises a group selected from (i) linear or branched aliphatic, aralkyl, or aromatic hydrocarbon groups having from 8 to 30 carbon atoms or (ii) alkyl or alkyl-ester groups having 8 to 30 carbon atoms; R2, R3, and R4 are independently selected from the group consisting of (a) linear or branched aliphatic hydrocarbon, fluorocarbon, or other halocarbon groups having from 1 to about 30 carbon atoms; (b) aralkyl or aromatic groups having from 6 to about 30 carbon atoms, (c) alkoxylated groups containing from 1 to about 80 moles of alkylene oxide; (d) amide groups, (e) oxazolidine groups, (f) allyl, vinyl, or other alkenyl or alkynyl groups possessing reactive unsaturation and having from 2 to about 30 carbon atoms, and (g) hydrogen; and Xxe2x80x2 comprises an anion selected from the group consisting of chloride, methyl sulfate, acetate, iodide, and bromide, preferably chloride. For purposes of this invention, quaternary phosphonium and sulfonium based salts are defined as within the definition of quaternary ammonium compound.
The raw materials used to make the quaternary amonium compounds can be derived from natural oils such as tallow, soya, coconut and palm oil. Useful aliphatic groups in the above formula may be derived from other naturally occurring oils including various vegetable oils, such as corn oil, coconut oil, soybean oil, cottonseed oil, castor oil and the like, as well as various animal oils or fats. The aliphatic groups may likewise be petrochemically derived from, for example, alpha olefins. Representative examples of useful branched, saturated radicals included 12-methylstearyl and 12-ethylstearyl.
Examples of useful aromatic groups include benzyl and benzylic-type materials derived from benzyl halides, benzhydryl halides, trityl halides, halo-phenylalkanes wherein the alkyl chain has from 1 to 30 carbon atoms, such as 1-halo-1-phenyloctadecane; substituted benzyl moieties, such as those derived from ortho-, meta-, and para-chlorobenzyl halides, para-methoxybenzyl halides, ortho-, meta-, and para-nitrilobenzyl halides, and ortho-, meta-, and para-alkylbenzyl halides wherein the alkyl chain contains from 1 to 30 carbon atoms; and fused ring benzyl-type moieties, such as those derived from 2-halomethylnaphthalene, 9-halomethylanthracene, and 9-halomethylphenanthrene, wherein the halo group comprises chloro, bromo, or any other such group which serves as a leaving group in the nucleophilic attack of the benzyl type moiety by a nitrogen atom to generate a substituted amine.
Examples of other aromatic groups include aromatic-type substituents such as phenyl and substituted phenyl; N-alkyl and N,N-dialkyl anilines, where the alkyl groups contain between 1 and 30 carbon atoms; ortho-, meta-, and para-nitrophenyl, ortho-, meta-, and para-alkyl phenyl, wherein the alkyl group contains between 1 and 30 carbon atoms; 2-,3-, and 4-halophenyl wherein the halo group is defined as chloro, bromo, or iodo; and 2-, 3-, and 4-carboxyphenyl and esters thereof, where the alcohol of the ester is derived from an alkyl alcohol, wherein the alkyl group contains between 1 and 30 carbon atoms, aryl such as phenol, or aralkyl such as benzyl alcohols; and fused ring aryl moieties such as naphthalene, anthracene, and phenanthrene.
Preferred quaternary ammonium compounds for purposes of the invention comprises a quaternary ammonium salt that contains at least one, preferably two or three, hydrocarbon chains having from about 8 to about 30 carbon atoms and either no hydrophilic carbon chains or having hydrophilic radicals having a total of about 9 moles of ethylene oxide or less.
Some examples of preferred quaternary ammonium compounds to make the compositions of this invention are: dimethyl bis[hydrogenated tallow] ammonium chloride (2M2HT), methyl benzyl bis[hydrogenated tallow] ammonium chloride (MB2HT), and methyl tris[hydrogenated tallow alkyl] chloride (M3HT).
Materials suitable for optional element (c) of this invention include materials listed as anionic components in U.S. Pat. Nos. 4,412,018, 4,434,075, and 4,577,112. These include materials that are capable of reacting with component (b) of this invention and for intercalation with component (a) as an alkyl quarternary ammonium-organic anion complex. The molecular weight (gram molecular weight) of the organic anion is preferably 3,000 or less, and most preferably 1,000 or less and contains at least one anionic moiety per molecule as disclosed herein. The organic anion is preferably derived from an organic acid having a pKA less than about 11.0. As indicated, the source acid must contain at least one ionizable hydrogen having the preferred pKA in order to allow the formation of the alkyl quarternary ammonium-organic anion complex.
Exemplary types of suitable acidic functional organic compounds useful in this invention include:
(1) Carboxylic Acids Including:
a) benzene carboxylic acids such as benzoic acid; ortho-, iso- and terephthalic acid; 1,2,3-benzenetricarboxylic acid; 1,2,4-benzenetricarboxylic acid; 1,3,5-benzenetricarboxylic acid; 1,2,4,5-benzenetetracarboxylic acid; 1,2,3,4,5,6-benzenehexacarboxylic acid (mellitic acid);
b) alkyl carboxylic acids having the formula CH3(CH2)nxe2x80x94COOH, wherein n is a number from 0 to 20; such compounds include acetic acid; pentanoic acid; hexanoic acid; heptanoic acid; octanoic acid; nonanoic acid; decanoic acid; undecanoic acid; lauric acid; tridecanoic acid; tetradecanoic acid; pentadecanoic acid; hexadecanoicanoic acid; heptadecanoic acid; octadecanoic acid (stearic acid); nonadecanoic acid; eicosonic acid.
c) Alkyl dicarboxylic acids having the formula HOOCxe2x80x94(CH2)nxe2x80x94COOH wherein n is 0 to 8 such as oxalic acid; malonic acid; succinic acid; glutaric acid; adipic acid; pimelic acid; suberic acid; azelaic acid; sebacic acid;
d) Hydroxyalkyl carboxylic acids such as citric acid; tartaric acids; malic acid; mandelic acid; and 12-hydroxystearic acid;
e) unsaturated alkyl carboxylic acids such as maleic acid; fumaric acid; and cinnamic acid;
f) Fused ring aromatic carboxylic acids such as naphthalenic acid and anthracenecarboxylic acid;
g) Cycloaliphatic acids such as cyclohexanecarboxylic acid; cyclopentanecarboxylic acid; furancarboxylic acids.
(2) Organic Sulfuric Acids Including:
a) sulfonic acids including:
1) benzenesulfonic acids such as benzenesulfonic acid; phenolsulfonic acid; dodecylbenzenesulfonic acid; benzenedisulfonic acid; benzenetrisulfonic acids; para-toluenesulfonic acid; and
2) alkyl sulfonic acids such as methanesulfonic acid; ethanesulfonic acid; butanesulfonic acid; butanedisulfonic acid; sulfosuccinate alkyl esters such as dioctyl succinylsulfonic acid; and alkyl polyethoxy-succinyl sulfonic acid; and
b) alkyl sulfates such as the lauryl half ester of sulfuric acid and the octadecyl half ester of sulfuric acid.
3) Organophosphorus acids including phosphonic acids, phosphinic acids, thiophosphinic acids, phosphites, and phosphates as described in U.S. Pat. No. 4,412,018
4) Phenols such as phenol; hydroquinone; t-butylcatechol; p-methoxyphenol; and naphthols.
5) Thioacids as described in U.S. Pat. No. 4,412,018.
6) Amino acids such as the naturally occurring amino acids and derivatives thereof such as 6-aminohexanoic acid; 12-aminododecanoic acid; N-phenylglycine; and 3-aminocrotonic acid.
Other materials useful for element c) can be selected from a wide variety of non-anionic materials as described in U.S. patent application Ser. No. 09/064216, descriptions herein incorporated by reference. These materials are either water soluble, liquid, or can be made into a liquid at reaction temperature so that the aforementioned clay materials absorbs them. These materials can be any of a wide range of materials and can have a wide range of molecular weights. Materials of this type suitable for element (c) of this invention include polyurethanes; polyamides; polyesters; polycarbonates; polyepoxides and polyolefins. Such materials also include polyethers (polymers and copolymers) based on ethylene oxide, butylene oxide, propylene oxide, phenols and bisphenols; polyesters (polymers and copolymers) based on aliphatic and aromatic diols and polyurethanes based on aliphatic and aromatic diisocyanates, polyamides (polymers and copolymers) based on aliphatic and aromatic diamines, and polycarbonates (polymers and copolymers) based on aliphatic or aromatic diols; polycarboimides (polymers and copolymers) based on tetrabasic acids and diamines, vinyl polymers and copolymers based on vinyl monomers, styrene and derivatives of styrene; acrylic polymers and copolymers based on acrylic monomers; copolymers based on styrene, vinyl and acrylic monomers; polyolefin polymers and copolymers based on ethylene, propylene and other alphaolefin monomers; polymers and copolymers based on dienes, isobutylenes and the like; and copolymers based on dienes, styrene, acryl and vinyl monomers. Other organic materials can include monomeric materials that have the functionality of the materials described above. The definition of element c) does not include quaternary ammonium compounds.
Specific preferred examples of useful non-anionic organic materials include THIXATROL VF-10 and THIXATROL VF-20 which are liquid polyester amide copolymers made by RHEOX. Examples of other specific materials are polyvinylpyrrolidone (PVP) or its hydrolysis product, polyvinyl alcohol (PVA), polymethacrylamide, poly(N,N-dimethylacrylamide), poly(N- isopropylacrylamide), poly(N-acetamidacryl amide), poly(N-acetimidomethacrylamide), polyvinyloxazolidone, and polyvinylmethyl oxazolidone, polyoxypropylene, polyoxyethylene and copolymers thereof.
The materials (b) and (c) can be reacted together, or in any order, with the smectite clay and the resultant product blended with the polymer to produce the inventive composition.
The amount of quaternary compound and optional organic compound used can vary over wide ranges. This amount is defined as the millequivalent ratio which is the number of milliequivalents (m.e.) of the organic cation in the organoclay per 100 grams of clay, 100% active clay basis.
Normally, where only a quaternary is employed, at least 90 to 100 m.e. of organic cation, more typically 100 to 140 m.e. of quaternary salt based on 100 g of 100% active clay are preferred although lower and higher ratios are also useful.
It is typical that component (c), if present, is used at an amount of 5 to 100 milliequivalents, and more preferably 10 to 50 m.e., per 100g of clay, 100% active basis.
The organoclays useful in the composites of this invention may be prepared in a number of ways. One is to first disperse the smectite clay in water. The clay is preferably dispersed in water at a concentration of from about 1 to 80%, most preferably from about 2 to 8% by weight. Optionally, the slurry may be centrifuged to remove non-clay impurities that constitute about 10% to 50% of the starting clay composition. If the optional organic material is to be part of the composition, it is added to the clay/water dispersion and mixed. This mixture can then be heated and is ion exchanged with a quaternary ammonium compound to form the final organoclay as a coagulate, which is washed with water and isolated by filtration. If only the optional organic material is used, it can be added to the purified clay/water slurry an adsorbed onto the clay. The clay is then isolated by drying.
A second general method to prepare this invention uses dry clay that is intimately mixed with the organic material in a heated device, such as an extruder. The mixture can also have some water present to facilitate intercalation. After the addition is complete, the quaternary ammonium compound and/or organic material is added and the final product is isolated. This composition can be washed with water and dried.
Both of the methods mentioned above where both components (b) and (c) are used can be modified by either: 1) reversing the order of addition, i.e., reacting the clay with the quaternary ammonium ion followed by the organic material; or 2) adding the quaternary ammonium compound and organic material to the clay simultaneously.
The reaction is preferably followed by drying and grinding the organoclay product. Incorporation of the organoclay into the plastic resin can be accomplished by mixing or blending the organoclay by any means that can create sufficient shear. The shear can be provided by any appropriate method such as mechanical, thermal shock, pressure changes, or ultrasonics as known in the art. Particularly useful are methods where a flowable polymer is mixed with the organoclay by mechanical means such as extruders, roll mills, stirrers, Banbury(copyright) type mixers, Brabender(copyright) type mixers, and continuous mixers. Other methods for making this invention can be postulated by those knowledgeable in the art.
Polymer compositions that are made by these methods using the compositions of this invention will exhibit improved fire retardancy when sufficient energy is imparted to the blend to create dispersed but not completely delaminated mixtures. This can be achieved by manipulation of various processing variables, for example: a) adjusting process temperature to raise or lower melt viscosity, b) adjusting time of processing or residence time, and c) changing machinery components such as extruder screw segments to provide a different shear processing profile.
A preferred method of determining a useful composition, as shown in the examples, is that it exhibits a discernable door peak for the smectite clay by XRD.
The preferred amounts and types of clays, quaternary ammonium compounds, organic materials, and polymers used to make the compositions of this invention will vary depending upon the type of matrix polymer that each composition is to be mixed into, with the goal to achieve incomplete delamination of the clay platelets in the matrix polymer.
In an important aspect of this invention, the milliequivalent ratio of clay to organic compound(s) is important. A preferred clay/organic chemical composition for purposes of the instant invention is comprised of:
1. The reaction product of:
(a) a smectite-type clay having a cation exchange capacity of preferably at least 50 milliequivalents per 100 grams of clay; and
(b) one or more quaternary ammonium compounds in an amount of from about 50% to about 150% of the cation exchange capacity of the smectite-type clay and/or
(c) one or more organic materials in an amount of 1% to 50% of the weight of the smectite-type clay; and
2. One or more polymer resins or copolymers where the amount of organoclay from the reaction of (a), (b) and (c) above is from 0.1% to 40% of the weight of the polymer resin.
The smectite-type clay can be sheared in slurry form prior to reaction with the organic materials, or treated in solid form with a pugmill or similar apparatus.

Organoclay/polymer compositions with flame retardant properties

Abstract: The inventive compositions have the property that when the organically modified clay is added to the polymer, a composite results which has flame-retardant properties and is based on the finding that degree of dispersion of a smectite organoclay in a polymer matrix will give the compositions flame-retardant properties. Further, it has been found that it is very important to proper functioning of the flame retardant polymer compositions that they have the organoclay dispersed in the polymer such that it is not completely exfoliated.


A method and apparatus for surgically repairing a tear in soft tissue is disclosed. A plurality of collapsible tubes are positioned about the suture. The collapsible tubes are pushed through soft tissue and orthopedic mesh on opposite sides of a tear in soft tissue. When tension is applied to the suture, the tubes are compressed to fix the suture to the soft tissue and draw the soft tissue portions together.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
It is commonplace in arthroscopic procedures to employ sutures and anchors to secure soft tissues to bone. Despite their widespread use, several improvements in the use of sutures and suture anchors may be made. For example, the procedure of tying knots may be very time consuming, thereby increasing the cost of the procedure and limiting the capacity of the surgeon. Furthermore, the strength of the repair may be limited by the strength of the knot. This latter drawback may be of particular significance if the knot is tied improperly as the strength of the knot in such situations may be significantly lower than the tensile strength of the suture material.
To improve on these uses, suture having a single preformed loop have been provided. FIG. 1 represents a prior art suture construction. As shown, one end of the suture is passed through a passage defined in the suture itself. The application of tension to the ends of the suture pulls a portion of the suture through the passage, causing a loop formed in the suture to close. Relaxation of the system, however may allow a portion of the suture to translate back through the passage, thus relieving the desired tension.
It is an object of the present teachings to provide an alternative device for anchoring sutures to bone and soft tissue. The device, which is relatively simple in design and structure, is highly effective for its intended purpose.

This patent is subject to a terminal disclaimer.

Method and apparatus for coupling soft tissue to a bone


A pink colored automatic dishwasher detergent composition is formulated as a gel-like aqueous product of exceptionally good physical stability, low bottle residue, low cup leakage, red color stability and improved cleaning performance.

The present invention relates generally to an automatic dishwasher detergent composition in the form of an aqueous liquid, wherein the composition is pink in color.
Liquid automatic dishwasher detergent compositions, both aqueous and nonaqueous, have recently received much attention, and the aqueous products have achieved commercial popularity.
The acceptance and popularity of the liquid formulations as compared to the more conventional powder products stems from the convenience and performance of the liquid products. However, even the best of the currently available liquid formulations still suffer from two major problems, product phase instability and bottle residue, and to some extent cup leakage from the dispenser cup of the automatic dishwashing machine as well as unacceptable color appearance.
Representative of the relevant patent art in this area, mention is made of Rek, U.S. Pat. No. 4,556,504; Bush, et al., U.S. Pat. No. 4,226,736; Ulrich, U.S. Pat. 4,431,559; Sabatelli, U.S. Pat. No. 4,147,650; Paucot, U.S. Pat. No. 4,079,015; Leikhem, U.S. Pat. No. 4,116,849; Milora, U.S. Pat. No. 4,521,332; Jones, U.S. Pat. No. 4,597,889; Heile, U.S. Pat. No. 4,512,908; Laitem, U.S. Pat. No. 4,753,748; Sabatelli, U.S. Pat. No. 3,579,455; Hynam, U.S. Pat. No. 3,684,722: other patents relating to thickened detergent compositions include U.S. Pat. No. 3,985,668; U.K. Pat. No. Applications GB 2,116,199A and GB 240,450A; U.S. Pat. No. 4,511,487; U.S. Pat. No. 4,752,409 (Drapier, et al.); U.S. Pat. No. 4,801,395 (Drapier, et al.); U.S. Pat. No. 4,801,395 (Drapier, et al.).
All of the prior art examples are yellow in yellow. The instant compositions are bleach stable and pink in appearance.
According to the present invention there is provided a novel aqueous liquid automatic dishwasher detergent composition which is pink in color and bleach stable. The composition is characterized by its substantially indefinite stability against phase separation or settling of dissolved or suspended particles, low levels of bottle residue, relatively high bulk density, a pink colored composition which is stable in the presence of bleach and substantial absence of unbound or free water. This unique combination of properties is achieved by virtue of the incorporation into the aqueous mixture of dishwashing detergent surfactant, optionally, an alkali metal detergent builder salt(s), chlorine bleach compound, an effective amount of high molecular weight cross-linked polyacrylic acid type thickening agent; a physical stabilizing amount of a long chain fatty acid or salt thereof; optionally, a noncrosslinked polyacrylate type polymer and a bleach stable red colorant thereby forming a pink colored liquid gelled automatic dishwashing composition. The compositions are further characterized by a bulk density of at least 1.24 g/cc, such that the density of the polymeric phase and the density of the aqueous (continuous) phase are approximately the same.
The compositions of this invention are pink colored, aqueous liquids containing various cleansing active ingredients, detergent adjuvants, structuring and thickening agents and stabilizing components, although some ingredients may serve more than one of these functions.
The advantageous characteristics of the compositions of this invention, including a bleach stable pink color physical stability, low bottle residue, high cleaning performance, e.g. low spotting and filming, food removal, and so on, and superior aesthetics, are believed to be attributed to several interrelated factors such as low solids, i.e. undissolved particulate content, product density and linear viscoelastic rheology. These factors are, in turn, dependent on several critical compositional components of the formulations, namely, (1) the inclusion of a thickening effective amount of polymeric thickening agent having high water absorption capacity, exemplified by high molecular weight cross-linked polyacrylic acid, (2) inclusion of a physical stabilizing amount of a long chain fatty acid or salt thereof, (3) a product bulk density of at least 1.24 g/cc, such that the bulk density and liquid phase density are about the same.
The pink colored, liquid gelled automatic dishwashing composition comprises approximately by weight:
(a) 0.1% to 55%, more preferably 5% to 40% of an inorganic compound containing alkali metal cations, preferably sodium ions, wherein said inorganic compound is selected from the group consisting of alkali metal detergent builder salts, alkali metal hydroxides and alkali metal silicates and mixtures thereof;
(b) 0.1% to 5% of at least one chlorine bleach stable, water-dispersible organic detergent active material;
(c) 0 to 2%, more preferably 0.05% to 1.75% chlorine bleach stable foam depressant;
(d) at least one chlorine bleach compound in an amount to provide about 0.2% to 4% of available chlorine;
(e) 0.1% to 2.5%, more preferably 0.2% to 1.5% of a high molecular weight hydrophilic cross-linked polyacrylic acid thickening agent;
(f) 0 to 5%, more preferably 0. 1% to 4.0% of a low molecular weight non-crosslinked polyacrylate-type polymer;
(g) 0 to 2%, more preferably 0.05% to 1% of a long chain fatty acid or a metal salt of a fatty acid;
(h) 0.001% to 0.5%, more preferably 0.001% to 0.2% of a F203 C.l. Pigment Red 1010 colorant; and
(i) the balance being water, wherein the composition is pink in color and has chromaticity coordinate values of x from about 0.3142 to about 0.3300 and, more preferably about 0.3162 to about 0.3290 and y from about 0.3233 to about 0.3450, more preferably 0.3253 to 0.3425. The x and y values were obtained from the tristimulus values (x, y and z) obtained from measurements made using a QA Master spherical spectrophotometer (X-Rite Corp.), 10 degree observer, D65 illuminant at 25xc2x0 C. and calibrated BTILL=barium sulfate, reflectance mode, specular component included, UV component included, large area view (sample and lens). CIELAB coordinates in the CIELAB system for the composition are (a) equals from about 1.25 to about 1.75, more preferably about 1.30 to about 1.64 and (b) from about xe2x88x920.1 to about +4.0, more preferably from about xe2x88x920.05 to about +3.5; L is about 28 to about 40, more preferably about 30 to about 39, C is about 1.0 to about 4, more preferably about 1.25 to about 3.75 and h is about xe2x88x920.1 to about +0.1, more preferably about xe2x88x920.05 to about +0.05.
Exemplary of the cross-linked polyacrylic acid-type thickening agents are the products sold by B.F. Goodrich under their Carbopol trademark, especially Carbopol 941, which is the most ion-insensitive of this class of polymers, and Carbopol 940 and Carbopol 934. The Carbopol resins, also known as xe2x80x9cCarbomerxe2x80x9d, are hydrophilic high molecular weight, cross-linked acrylic acid polymers having an average equivalent weight of 76, and the general structure illustrated by the following formula:
Carbopol 941 has a molecular weight of 1,250,000; Carbopol 940 a molecular weight of approximately 4,000,000 and Carbopol 934 a molecular weight of approximately 3,000,000. The Carbopol resins are cross-linked with polyalkenyl polyether, e.g. 1% of a polyallyl ether of sucrose having an average of 5.8 allyl groups for each molecule of sucrose. Further detailed information on the Carbopol resins is available from B.F. Goodrich, see, for example, the B.F. Goodrich catalog GC-67, Carbopol(copyright) Water Soluble Resins.
While most favorable results have been achieved with Carbopol 614 or 617 from BF Goodrich or the Polygel series from 3V Company, preferably Polygel TL, other lightly cross-linked polyacrylic acid-type thickening agents can also be used in the compositions of this invention. As used herein xe2x80x9cpolyacrylic acid-typexe2x80x9d refers to water-soluble homopolymers of acrylic acid or methacrylic acid or water-dispersible or water-soluble salts, esters or amides thereof, or water-soluble copolymers of these acids of their salts, esters or ameides with each other or with one or more other etylenically unsaturated monomers, such as, for example, styrene, maleic acid, maleic anhydride, 2-hydroxyethylacrylate, acrylonitrile, vinyl acetate, ethylene, propylene, and the like.
These homopolymers or copolymers are characterized by their high molecular weight, in the range of from about 500,000 to 10,000,000, preferably 500,000 to 5,000,000, especially from 1,000,000 to 4,000,000, and by their water solubility, generally at least to an extent of up to 5% by weight, or more, in water at 250xc2x0 C.
These thickening agents are used in their lightly cross-linked form wherein the cross-linking may be accomplished by means known in the polymer arts, as by irradiation, or, preferably, by the incorporation into the monomer mixture to be polymerized of known chemical cross-linking monomeric agents, typically polyunsaturated (e.g. diethylenically unsaturated) monomers, such as, for example, divinylbenzene, divinylether of diethylene glycol, N, Nxe2x80x2-methylene-bisacrylamide, polyalkenylpolyethers (such as described above), and the like. Typically, amounts of cross-linking agent to be incorporated in the final polymer may range from about 0.01 to about 1.5 percent, preferably from about 0.05 to about 1.2 percent, and especially, preferably from about 0.1 to about 0.9 percent, by weight of cross-linking agent to weight of total polymer. Generally, those skilled in the art will recognize that the degree of cross-linking should be sufficient to impart some coiling of the otherwise generally linear polymeric compound while maintaining the cross-linked polymer at least water dispersible and highly water-swellable in an ionic aqueous medium. It is also understood that the water-swelling of the polymer which provides the desired thickening and viscous properties generally depends on one or two mechanisms, namely, conversion of the acid group containing polymers to the corresponding salts, e.g. sodium, generating negative charges along the polymer backbone, thereby causing the coiled molecules to expand and thicken the aqueous solution; or by formation of hydrogen bonds, for example, between the carboxyl groups of the polymer and hydroxyl donor. The former mechanism is especially important in the present invention, and therefore, the preferred polyacrylic acid-type thickening agents will contain free carboxylic acid (COOH) groups along the polymer backbone. Also, it will be understood that the degree of cross-linking should not be so high as to render the cross-linked polymer completely insoluble or non-dispersible in water or inhibit or prevent the uncoiling of the polymer molecules in the presence of the ionic aqueous system.
The amount of the high molecular weight, cross-linked polyacrylic acid or other high molecular weight, hydrophilic cross-linked polyacrylic acid-type thickening agent to impart the desired Theological property of linear viscoelasticity will generally be in the range of from about 0.1 to 2.5%, preferably from about 0.2 to 1.5%, by weight, based on the weight of the composition, although the amount will depend on the particular cross-linking agent, ionic strength of the composition, hydroxyl donors and the like.
Specific examples of the alkali metal detergent builder salts include the polyphosphates, such as alkali metal pyrophosphate, alkali metal tripolyphosphate, alkali metal metaphosphate, and the like, for example, sodium or potassium tripolyphosphate (hydrated or anhydrous), tetrasodium or tetrapotassium pyrophosphate, sodium or potassium hexa-metaphosphate, trisodium or tripotassium orthophosphate and the like, sodium or potassium carbonate, sodium or potassium citrate, sodium or potassium nitrilotriacetate, and the like. The phosphate builders, where not precluded due to local regulations, are preferred and mixtures of tetrapotassium pyrophosphate (TKPP), potassium tripolyphosphate (KTPP), and sodium tripolyphosphate (NaTPP) (especially the hexahydrate) are especially preferred. Typical ratios of NaTPP to TKPP are from about 2:1 to 1:8, especially from about 1:1.1 to 1:6. The total amount of detergent builder salts is preferably from about 2 to 15%.
The gelled compositions of this invention may, contain a small, but stabilizing effective amount of a long chain fatty acid or monovalent or polyvalent salt thereof. Although the manner by which the fatty acid or salt contributes to the rheology and stability of the composition has not been fully elucidated it is hypothesized that it may function as a hydrogen bonding agent or cross-linking agent for the polymeric thickener. The preferred long chain fatty acids are the higher aliphatic fatty acids having from about 8 to 22 carbon atoms, more preferably from about to carbon atoms, and especially preferably from about 12 to 18 carbon atoms, and especially preferably from 12 to 18 carbon atoms, inclusive of the carbon atom of the carboxyl group of the fatty acid. The aliphatic radical may be saturated or unsaturated and may be straight or branched. Straight chain saturated fatty acids are preferred. Mixtures of fatty acids may be used, such as those derived from natural sources, such as tallow fatty acid, coco fatty acid, soya fatty acid, mixtures of these acids, etc. Stearic acid and mixed fatty acids, e.g. stearic acid/palmitic acid, are preferred.
Thus, examples of the fatty acids include, for example, decanoic acid, dodecanoic acid, palmitic acid, myristic acid, stearic acid, behenic acid, oleic acid, eicosanoic acid, tallow fatty acid, coco fatty acid, soya fatty acid, mixtures of these acids, etc. Stearic acid and mixed fatty acids, e.g. stearic acid/palmitic acid, are preferred.
When the free acid form of the fatty acid is used directly it will generally associate with the potassium and sodium ions in the aqueous phase to form the corresponding alkali metal fatty acid soap. However, the fatty acid salts may be directly added to the composition as sodium salt or potassium salt, or as a polyvalent metal salt, although the alkali metal salts of the fatty acids are preferred fatty acid salts.
The preferred polyvalent metals are the di- and tri-valent metals of Groups IIA, IIB and IIIB, such as magnesium, calcium, aluminum and zinc, although other polyvalent metals, including those of Groups IIIA, IVA, VA, IB, IVB, VB VIB, VIIB and VIII of the Periodic Table of the Elements can also be used. Specific examples of such other polyvalent metals include Ti, Zr, V, Nb, Mn, Fe, Co, Ni, Cd, Sn, Sb, Bi, etc. Generally, the metals may be present in the divalent to pentavalent state. Preferably the metal salts are used in their higher oxidation states. Naturally, for use in automatic dishwashers, as well as any other applications where the invention composition will or may come in contact with articles used for the handling, storage or serving of food products or which otherwise may come into contact with or be consumed by people or animals, the metal salt should be selected by taking into consideration the toxicity of the metal. For this purpose, the alkali metal and calcium and magnesium salts are especially higher preferred as generally safe food additives.
The amount of the fatty acid or fatty acid salt stabilizer to achieve the desired enhancement of physical stability will depend on such factors as the nature of the fatty acid or its salt, the nature and amount of the thickening agent, amount of the acidic sol of the alumina, detergent active compound, inorganic salts, other ingredients, as well as the anticipated storage and shipping conditions.
Generally, however, amounts of the fatty acid or fatty acid salt stabilizing agents in the range of from about 0 to 2%, preferably 0.05 to 1%, more preferably from about 0.08 to 0.8% provide a long term stability and absence of phase separation upon standing or during transport at both low and elevated temperatures as are required for a commercially acceptable product.
Depending on the amounts, proportions and types of fatty acid physical stabilizers, the amount of the acidic sol of the alumina and polyacrylic acid-type thickening agents, the addition of the fatty acid or salt not only increases physical stability but also provides a simultaneous increase in apparent viscosity.
Foam inhibition is important to increase dishwasher machine efficiency and minimize destabilizing effects which might occur due to the presence of excess foam within the washer during use. Foam may be reduce by suitable selection of the type and/or amount of detergent active material, the main foam-producing component. The degree of foam is also somewhat dependent on the hardness of the wash water in the machine whereby suitable adjustment of the proportions of the builder salts such as NaTPP which has a water softening effect, may aid in providing a degree of foam inhibition. However, it is generally preferred to include a chlorine bleach stable foam depressant or inhibitor. Particularly effective are the alkyl phosphoric acid esters of the formula
and especially the alkyl acid phosphate esters of the formula
In the above formulas, one or both R groups in each type of ester may represent independently a C12-C20 alkyl or ethoxylated alkyl group. The ethoxylated derivatives of each type of ester, for example, the condensation products of one mole of ester with from 1 to moles, preferably 2 to 6 moles, more preferably 3 or 4 moles, ethylene oxide can also be used. Some examples of the foregoing are commercially available, such as the products SAP from Hooker and LPKN158 from Clariant. Mixtures of the two types, or any other chlorine bleach stable types, or mixtures of mono- and di-esters of the same type, may be employed. Especially preferred is a mixture of mono- and di-C16-C18 alkyl acid phosphate esters such as monostearyl/distearyl acid phosphates 1.2/1, and the 3 to 4 mole ethylene oxide condensates thereof. When employed, proportions of 0.05 to 2.0 weight percent, preferably 0.1 to 0.5 weight percent, of foam depressant in the composition is typical, the weight ratio of detergent active component (d) to foam depressant (e) generally ranging from 10:1 to 1:1 and preferably 5:1 to 1:1. Other defoamers which may be used include, for example, the known silicones, such as available from Dow Chemicals. In addition, it is an advantageous feature of this invention that many of the stabilizing salts, such as the stearate salts, for example, aluminum stearate, when included, are also effective as foam killers.
Although any chlorine bleach compound may be employed in the compositions of this invention, such as dichloro-isocyanurate, dichloro-dimethyl hydantoin, or chlorinated TSP, alkali metal or alkaline earth metal, e.g. potassium, lithium, magnesium and especially sodium, hypochlorite is preferred. The composition should contain sufficient amount of chlorine bleach compound to provide about 0.2 to 4.0% by weight of available chlorine, as determined, for example by acidification of 100 parts of the composition with excess hydrochloric acid. A solution containing about 0.2 to 4.0% by weight of sodium hypochlorite contains or provides roughly the same percentage of available chlorine. About 0.8 to 1.6% by weight of available chlorine is especially preferred. For example, sodium hypochlorite (NaOCI) solution of from about 11 to about 13% available chlorine in amounts of about 3 to 20%, preferably about 7 to 12%, can be advantageously used.
Detergent active material useful herein should be stable in the presence of chlorine bleach, especially hypochlorite bleach, and for this purpose those of the organic anionic, amine oxide, phosphine oxide, sulphoxide or betaine water dispersible surfactant types are preferred, the first mentioned anionics being most preferred. Particularly preferred surfactants herein are the linear or branched alkali metal mono- and/or di-(C8-C14) alkyl diphenyl oxide mono- and/or di-sulphates, commercially available for example as DOWFAX (registered trademark) 3B-2 and DOWFAX 2A-1. In addition, the surfactant should be compatible with the other ingredients of the composition. Other suitable organic anionic, non-soap surfactants include the primary alkylsulphates, alkylsulphonates, alkylarylsulphonates and sec.-alkylsulphates. Examples include sodium C10-C18 alkylsulphates such as sodium dodecylsulphate and sodium tallow alcoholsulphate; sodium C10-C18 alkanesulphonates such as sodium hexadecyl-1-sulphonate and sodium C12-C18 alkylbenzenesulphonates such as sodium dodecylbenzenesylphonates. The corresponding potassium salts may also be employed.
As other suitable surfactants or detergents, the amine oxide surfactants are typically of the structure R2R1 NO, in which each R represents a lower alkyl group, for instance, methyl, and R1 represents a long chain alkyl group having from 8 to 22 carbon atoms, for instance a lauryl, myristyl, palmityl or cetyl group. Instead of an amine oxide, a corresponding surfactant phosphine oxide R2R1 PO or sulphoxide RR1SO can be employed. Betaine surfactants are typically of the structure R2R1N+RCOO-, in which each R represents a lower alkylene group having from 1 to 5 carbon atoms. Specific examples of these surfactants include lauryl-dimethylamine oxide, myristyl-dimethylamine oxide, myristyl-dimethylamine oxide, the corresponding phosphine oxides and sulphoxides, and the corresponding betaines, including dodecyidimethylammonium acetate, tetradecyidiethylammonium pentanoate, hexadecyldimethylammonium hexanoate and the like. For biodegradability, the alkyl groups in these surfactants should be linear, and such compounds are preferred.
Surfactants of the foregoing type, all well known in the art, are described, for example, in U.S. Pat. Nos. 3,985,668 and 4,271,030. If chlorine bleach is not used than any of the well known low-foaming nonionic surfactants such as alkoxylated fatty alcohols, e.g. mixed ethylene oxide-propylene oxide condensates of C8-C22 fatty alcohols can also be used.
The chlorine bleach stable, water dispersible organic detergent-active material (surfactant) will normally be present in the composition in minor amounts, generally about 1% by weight of the composition, although smaller or larger amounts, such as up to about 5%, such as from 0.1 to 5%, preferably form 0.3 or 0.4 to 2% by weight of the composition, may be used.
Alkali metal (e.g. potassium or sodium) silicate, which provides alkalinity and protection of hard surfaces, such as fine china glaze and pattern, is generally employed in an amount ranging from about to weight percent, preferably about 5 to 15 weight percent, more preferably 8 to 12% in the composition. The sodium or potassium silicate is generally added in the form of an aqueous solution, preferably having Na2O:SiO2 or K2O:SiO2 ratio of about 1:1.3 to 1:2.8, especially preferably 1:2.0 to 1:2.6. At this point, it should be mentioned that many of the other components of this composition, especially alkali metal hydroxide and bleach, are also often added in the form of a preliminary prepared aqueous dispersion or solution.
In addition to the detergent active surfactant, foam inhibitor, alkali metal silicate corrosion inhibitor, and detergent builder salts, which all contribute to the cleaning performance, it is also known that the effectiveness of the liquid automatic dishwasher detergent compositions is related to the alkalinity, and particularly to moderate to high alkalinity levels. Accordingly, the compositions of this invention will have pH values of at least about 9.5, preferably at least about 11 to as high as 14, generally up to about 13 or more, and, when added to the aqueous wash bath at a typical concentration level of grams per liter, will provide a pH in the wash bath of at least 9, preferably at least about 10, such as 10.5, 11, 11.5 or 12 or more.
The alkalinity will be achieved, in part by the alkali metal ions contributed by the alkali metal detergent builder salts, e.g. sodium tripolyphosphate, tetrapotassium pyrophosphate, and alkali metal silicate, however, it is usually necessary to include at least alkali metal hydroxide, e.g. NaOH or KOH, to achieve the desired high alkalinity.
Other alkali metal salts, such as alkali metal carbonate may also be present in the compositions in minor amounts, for example from 0 to 4%, preferably 0.1 to 2%, by weight of the composition.
The preferred low molecular noncrosslinked polyacrylate polymer is an alkali metal salt such as sodium of a noncrosslinked polyacrylic acid homopolymer having a molecular weight of about 1,000 to about 20,000, preferably about 2,000 to about 4,000. A preferred polymer is Aucsol(trademark) 445N sold by Rohm Haas which has a molecular weight of about 4,500.
The red colorant that is bleach stable which is used in the instant compositions is a ferric oxide (Fe203) red pigment sold by Bayer as Levanox Red 130LF01 red dispersion pigment of 60-65% Cl pigment. Red 101, silicon dioxide less than 3%, nonionic surfactant dispersant 5-10% and the balance being water. A solution of 98.7% of water, 0.8% Levanox Red 130 LFO1 dispersion and 0.5 of 50% sodium hydroxide aqueous solution is prepared and added to the liquid, gel automatic dishwashing composition.
Other conventional ingredients may be included in these compositions in small amounts, generally less than 3 weight percent, such as perfume, hydrotropic agents such as the sodium benzene, toluene, xylene and cumene sulphonates and preservatives, all of course being stable to chlorine bleach compound and high alkalinity.
The manner of formulating the invention compositions is also important. As discussed above, the order of mixing the ingredients as well as the manner in which the mixing is performed will generally have a significant effect on the properties of the composition, and in particular on product density (by incorporation and stabilization of more or less air) and physical stability (e.g. phase separation). Thus, according to the preferred practice of this invention the compositions are prepared by first forming a dispersion of the polyacrylic acid-type thickener and the low molecular weight noncrosslinked polyacrylate in water under moderate to high shear conditions, neutralizing the dissolved polymer to cause gelation and then introducing, while continuing mixing, the detergent builder salts, alkali metal dilicates, chlorine bleach compound and remaining detergent additives, including any previously unused alkali metal hydroxide, if any, other than the surface-active compounds. All of the additional ingredients can be added simultaneously or sequentially. Preferably, the ingredients are added sequentially, although it is not necessary to complete the addition of one ingredient before beginning to add the next ingredient. Furthermore, one or more of these ingredients can be divided into portions and added at different times. These mixing steps should also be performed under moderate to high shear rates to achieve complete and uniform mixing. These mixing steps may be carried out at room temperature, although the polymer thickener neutralization (gelation) is usually exothermic. The composition may be allowed to age, if necessary, to cause dissolved or dispersed air to dissipate out of the composition.
The remaining surface active ingredients, including the anti-foaming agent, organic detergent compound, and fatty acid or fatty acid salt stabilizer is post-added to the previously formed mixture in the form of an aqueous emulsion (using from about 1 to 10%, preferably from about 2 to 4% of the total water added to the composition other than water added as carrier for other ingredients or water of hydration) which is pre-heated to a temperature in the range of from Tm+5 to Tmxe2x88x9220, preferably from Tm to TMxe2x88x9210, where Tm is the melting point temperature of the fatty acid or fatty acid salt. For the preferred stearic acid stabilizer the heating temperature is in the range of 50xc2x0 C. to 70xc2x0 C. However, if care is taken to avoid excessive air bubble incorporation during the gelatin step or during the mixing of the detergent builder salts F203 (ferric oxide) red pigment and other additives, for example, by operating under vacuum, or using low shearing conditions, or special mixing operatatus, etc., the order of addition of the surface active ingredients should be less important.
The compositions will be supplied to the consumer in suitable dispenser containers preferably formed of molded plastic, especially polyolefin plastic, and most preferably polyethylene, for which the invention compositions appear to have particularly favorable slip characteristics. In addition to their linear viscoelastic character, the compositions of this invention may also be characterized as pseudoplastic gels (non-thixotropic) which are typically near the borderline between liquid and solid viscoelastic gel, depending, for example, on the amount of the polymeric thickener. The invention compositions can be readily poured from their containers without any shaking or squeezing, although squeezable containers are often convenient and accepted by the consumer for gel-like products.
The liquid, gelled automatic dishwasher compositions of this invention are readily employed in known manner for washing dishes, other kitchen utensils and the like in an automatic dishwasher, provided with a suitable detergent dispenser, in an aqueous wash bath containing an effective amount of the composition, generally sufficient to fill or partially fill the automatic dispenser cup of the particular machine being used.
The invention also provides a method for cleaning dishware in an automatic dishwashing machine with an aqueous wash bath containing an effective amount of the liquid, gelled automatic dishwasher detergent composition as described above. The composition can be readily poured from the polyethylene container with little or no squeezing or shaking into the dispensing cup of the automatic dishwashing machine and will be sufficiently viscous and cohesive to remain securely within the dispensing cup until shear forces are again applied thereto, such as by the water spray from the dishwashing machine.
The invention may be put into practice in various ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying examples.
All the amounts and proportions referred to herein are by weight of the composition unless otherwise indicated.

Pink colored, aqueous liquid automatic dishwasher detergent composition