The invention is directed to amphipathic polymeric particles that serve as both the dispersant and the binder in water based inks, ink compositions containing these particles, and methods for making the particles. The polymeric particles contain both hydrophilic and hydrophobic moieties with a pre-determined structure, and have an average diameter of 50 to 500 nm. The amphipathic polymeric particles may be prepared by a side-chain conversion method or a polymerization process involving an ATRP step, with or without a cross-linking agent. This invention improves the stability of polymer and inks by both ionic and steric stabilization of the suspended polymer particles.

The technical field relates to amphipathic polymeric particles that serve as dispersants and binders in ink compositions, ink compositions containing the same, and methods for making the particles and the inks. More specifically, the technical field relates to polymeric particles that increase the suspension stability, water fastness, smear fastness, and light fastness of inks.
Inks are among the oldest known technologies. Historians believe inks were utilized in China and Egypt as early as 2,500 B.C. Nonetheless, significant advances in the ink art continue to occur, especially when formulating compositions for use in more modem dispensers such as ink jet printers.
Inks for use in ink jet printers generally comprise an aqueous carrier and a colorant. The colorant can be a dye or a pigmentxe2x80x94the distinction being that dyes are soluble in aqueous and/or organic solvents whereas pigments are relatively insoluble.
Inks containing soluble dyes, however, exhibit numerous problems. These problems include: poor water fastness; poor light fastness; clogging of the ink jet channels as a result of solvent evaporation, changes in the dye solubility, and/or dye crystallization; bleeding and feathering on the printed page; poor thermal stability; and chemical instability, including but not limited to poor oxidation resistance.
Many of these problems are minimized by replacing the dyes with pigments. In general, pigments have superior properties when compared to dyes, including good water fastness, good light fastness, thermal stability, oxidative stability and compatibility with paper. However, difficulties are encountered in maintaining the pigments in a stable and uniform suspension. If the pigments coagulate and/or fall out of suspension, the utility of the ink is greatly diminished, if not completely destroyed.
Polymeric dispersants are often employed to increase the shelf life of the pigment suspensions. Generally speaking, these dispersants contain hydrophobic groups that absorb onto the pigment particle surfaces through acid-base interactions, Van der Waals forces, or physical entanglement or entrapment. In addition, the dispersants contain hydrophilic groups that extend out into the aqueous medium. In this way, the dispersants associate the pigment with the aqueous carrier.
In the dispersant, large particles are undesirable since they clog the ink jet and are difficult to be suspend in water over a long period of time without settlement. Moreover, it is difficult to precisely control the identity, length, weight and distribution of the hydrophobic and hydrophilic groups in the polymer dispersant. When these properties are not controlled, the dispersant may not be able to fully cover the water-insoluble pigments to create an electrostatic layer that prevents aggregation. In some cases, the dispersant may even act as a flocculent which is the opposite desired effect.
Regardless of the colorant employed, the adherence of the ink on the substrate is always a major issue. Colorants must be chemically or physically bound to the treated surface, e.g., paper, in order to prevent bleeding, smearing or rubbing after the ink has dried. Accordingly, polymeric binders are often employed to chemically and/or physically entrap the colorant.
The present inventor has conducted a great deal of research in the field of inks. Much of this work is directed to polymeric dispersants and/or binders. Patents that have issued on this work include the following: U.S. Pat. Nos. 5,972,552; 5,973,025; 5,990,202; 6,027,844; 6,057,384; 6,090,193; 6,117,222; 6,248,161 B1; and 6,248,805 B1. However, there remains a need for inks, that can be used in ink jet printers, which exhibit improved shelf-life, water fastness, smear fastness, and light fastness.
The invention is directed to amphipathic polymeric particles that serve as both the dispersant and the binder in water based inks. The particles have an average diameter of 50 to 400 nm with a pre-determined structure, making them ideal for inclusion in any ink marketed for ink jet printers.
In a preferred embodiment, the polymeric particles are formulated from a combination of hydrophilic and hydrophobic unsaturated monomers. Combining hydrophilic and hydrophobic moieties into the polymeric particles facilitates association between the ink""s aqueous carrier and water insoluble components. This association, in turn, increases the stability of the suspension and, thereby, the shelf-life of the ink. When the ink is applied to a substrate, e.g., paper, the particles bind the colorants to the substrate by forming a film over the colorants. The film conveys superior durability, e.g., water fastness, smear fastness, and light fastness, to the inked image.
In another preferred embodiment, a water-soluble dye with a polymerizable functional group is formulated into the polymeric particles. The optical density of the dye is preserved since it lies on the outside of the particle in the water phase. The dye itself acts like a stabilizing group for the particle. The durability of the printed images is enhanced since the dye is trapped in the water-insoluble dispersant which forms a protective film upon removal of water.
In yet another preferred embodiment, the shear stability of these polymers may be improved by incorporating cross-linkers to an extent of about 1% by weight.
The invention is also directed to methods for making the aforementioned particles. A preferred method employs an emulsion of water-insoluble long chain acid containing monomers (convertible monomers) and hydrophobic monomers to generate polymers that can be stably suspended in water over a long period of time. Specifically, the convertible monomers are introduced into the emulsion in a hydrophobic form and incorporated into the polymers. The side chain acid groups of the incorporated convertible monomers are then converted to anionic salts by adjusting the pH of the solution to a basic range (pH greater than 7). The acid-to-salt conversion changes the Zeta potential and net surface charge of the polymer particles, and increases the stability of the polymer particles in colloidal systems.
Another preferred method entails a combination of atom transfer radical polymerization (ATRP) and emulsion polymerization. By utilizing ATRP in the process, the molecular weight of the particles and the distribution of hydrophilic and hydrophobic moieties can be carefully controlled.
Finally, the invention is directed to an environmentally friendly, water based ink that contains a vehicle, a colorant, a surfactant, and the aforementioned polymeric particles. Due to the presence of the amphipathic polymeric particles, these inks exhibit improved dispersion and shear stability, shelf-life, water fastness, smear fastness, and light fastness.
Definitions
As defined herein, the term xe2x80x9cwater fastnessxe2x80x9d refers to the resistance of an impression to dilution or removal by water. A water fast ink has a reduced tendency to wick, feather or be washed away. Water fastness can be measured by wetting the printing area with water and determining the optical density (OD) in the neighboring areas (defined as xe2x80x9cbackground ODxe2x80x9d) before and after the exposure to water.
As defined herein, the term xe2x80x9csmear fastnessxe2x80x9d refers to the resistance of an image to smear on contact with a hard object, such as the tip of a highlighter, under normal pressure. A smear is defined as the transfer of colorant from the printing area to the neighboring areas (background) by the object. Smear fastness can be measured by determining the change of the background OD after subjecting the printing area to a standard smearing force.
As defined herein, the term xe2x80x9clight fastnessxe2x80x9d refers to the durability of a print when exposed to light. When an ink is light fast, it has fade resistance. It is generally thought that pigments have improved fade resistance over dyes but some of the newer dyes have shown that they can be comparable.
As defined herein, the term xe2x80x9cshear stabilityxe2x80x9d refers to the polymer particles"" ability to maintain their original size under mechanical stress. Shear stability can be measured by subjecting the particles to mechanical stress and determining the change in particle size.
As defined herein, the term xe2x80x9cconvertible monomerxe2x80x9d refers to monomers with long side chain acid groups. The convertible monomers are water insoluble in the monomer form. After polymerization, the acid group on the side chain of the convertible monomers can be converted to anionic salt by adjusting the pH of the solution to a basic range (pH greater than 7), i.e., the hydrophobic monomer is incorporated into the polymer as a hydrophobic moiety, but is converted to a hydrophilic moiety under basic pH.
The polymeric particles of the present invention are formulated from a combination of convertible and hydrophobic unsaturated monomers (for methods involving side chain conversion) or a combination of hydrophilic and hydrophobic unsaturated monomers (for methods using ATRP process). The convertible or hydrophilic units of the polymer may be in the range of 1%-60% by weight, and preferably about 10% by weight. The hydrophobic units of the polymer may be in the range of 30%-99% by weight, and preferably about 90% by weight.
The hydrophilic portions of the polymeric particles associate the particles with the aqueous carrier in the ink composition. Generally, hydrophilic moieties include acidic functional groups, such as carboxylic, sulfonic acid, or phosphoric acid groups.
Monomers that may be used to form the hydrophilic moieties include acrylic acid, acrylamide, methacrylic acid, styrene sulfonates, vinyl imidazole, vinyl pyrrolidone, poly(ethylene glycol) acrylates and methacrylates, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, methacrylamide, dimethylacrylamide, dimethylaminopropyl methacrylamide, ethylene glycol methacrylate phosphate, 2-(methacryloyloxy)ethyl phthalate, 2-(methacryloyloxy)ethyl succinate, 3-sulfopropyl methacrylate and 3-sulfopropyl acrylate. Protected monomers that generate acrylic or methacrylic acid after removal of the protecting group may also be used. Suitable protected monomers include trimethylsilyl methacrylate, trimethylsilyl acrylate, 1-butoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-butoxyethyl acrylate, 1-ethoxyethyl acrylate, 2-tetrahydropyranyl acrylate, 2-tetrahydropyranyl methacrylate, t-butyl methacrylate, t-butyl acrylate, methyl oxymethacrylate and vinyl benzoic acid. It should be noted that different monomers may require different polymerization conditions for optimal performance.
Preferred hydrophilic monomers are methacrylic acid, acrylic acid, and mixtures thereof.
Preferred convertible monomers are mono-methacryloyloxyethyl succinate, mono-acryloyloxyethyl succinate, mono-methacryloyloxyethyl phthalate, acrylamidobutyric acid, mono-methacryloyloxyethylmaleate and methacryloyloyethylphosphate.
The hydrophobic portions of the polymeric particles associate the particles with the insoluble organic pigment in the ink composition. Generally, hydrophobic moieties include alkyl, cycloalkyl, aromatic hydrocarbon, and styrene groups.
Monomers that may be used to form hydrophobic polymeric moieties include the following: C1-20 alkyl or cycloalkyl acrylates and methacrylates; C1-20 hydroxyalkyl acrylates and methacrylates, styrene, and mixtures thereof.
Preferred hydrophobic monomers are methyl methacrylate, butyl methacrylate, hexyl acrylate, ethyl hexylacrylate, styrene, and mixtures thereof.
The inclusion of hydrophilic and hydrophobic moieties in the polymeric particles facilitates the association of the ink""s aqueous carrier and the ink""s water insoluble components, such as pigments. This association, in turn, increases the stability of the suspension and, thereby, the shelf-life of the ink.
The shear stability of the polymer particles can be improved by incorporating cross-linkers into the polymers. Cross-linkers can be any monomers with polymerizable di- or polyfunctional groups. Preferred cross-linkers are ethylene glycol dimethacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, 3-(acryloyloxy)-2-hydroxypropyl methacrylate, ethyleneglycol dimethacrylamide, mono-2-(methacryloyloxyethyl) maleate, divinyl benzene, or other monomers with polymerizable di- or polyfunctional groups.
Cross linkers are utilized in a range of 0.1%-5% by weight of the total composition. Preferably, the extent of cross-linking is about 1% by weight, i.e., the final product contains 1% cross-linker by weight. The 1% cross-linking is sufficient to enhance shear stability without unduly affecting the physical properties of the polymer. However, polymers with low glass transition temperature ( less than 25xc2x0 C.) may need a higher amount of cross-linking, e.g., about 2% by weight.
Preparation of Amphipathic Polymers by Side-chain Conversion Method
In general, amphipathic polymers may be prepared by copolymerization of hydrophilic and hydrophobic monomers in an emulsion in the presence of surfactants. However, a major problem with the emulsion process is the low production rate of amphipathic polymers. Although both hydrophilic and hydrophobic monomers are present in the emulsion, they tend to stay in their respective phase of the emulsion and form hydrophilic or hydrophobic homopolymers (i.e., polymers containing only hydrophilic or hydrophobic monomers).
The present invention provides a method to produce amphipathic polymers with a desirable content of hydrophilic and hydrophobic moieties by starting the polymerization reaction with convertible monomers and hydrophobic monomers. The convertible monomers are long chain acid containing monomers that are capable of converting from a hydrophobic form to a hydrophilic form upon a change of pH. Because the emulsion has an acidic pH, the convertible monomers are in the hydrophobic form and can efficiently form heteropolymers with the hydrophobic monomers in the hydrophobic phase of the emulsion. After the polymerization, the acid group on the side chain of the convertible monomers may be converted to anionic salt form by adjusting the pH of the solution to a basic range (pH greater than 7). This conversion changes the Zeta potential and the net charge of the polymer, and stabilizes the particles in an aqueous solution.
The side chain conversion method comprises the following two steps:
(1) Copolymerization of Convertible and Hydrophobic Monomers in an Emulsion
An emulsion of monomer mixture is prepared by mixing hydrophobic monomers, convertible monomers, and surfactants with water. Polymerization is initiated by adding a catalyst, such as potassium persulfate, to the monomer mixture and heating the mixture to an elevated temperature. The copolymerization step may be carried out in the presence of a polymerizable dye monomer to generate polymer particles with the colorant trapped in them. The polymers may also be cross-linked using a cross-linker described above to improve the shear stability.
(2) Conversion of Side Chain Groups
Stop the polymerization by reducing the temperature of the reaction mixture. A base is added to bring the pH of the reaction mixture into a basic range (pH greater than 7). Examples of the base include, but are not limited to, sodium hydroxide, lithium hydroxide, potassium hydroxide and any organic amines or substituted organic amines or primary, secondary or tertiary amine. Examples of amines include, but are not limited to, triethyl amine, aminoethanol and diethylamine. The upshift of pH converts the side chain acid groups into anionic salts and changes the Zeta potential of the polymer particles. The reaction mixture may be filtered remove any precipitates formed during the polymerization. The polymeric particles obtained from the above-described process have an average diameter of 50 to 500 nm.
Preparation of Amphipathic Polymers by ATRP Method
The present invention also provides a method to control not only the hydrophilicity but also the size dispersivity of the amphipathic polymer particles.
The size of the polymer particles is an important concern in a ink composition. The nozzles in ink jet printers are decreasing in size. Nozzle openings are typically 50 to 80 xcexcm in width or diameter for 300 dpi printers and 10 to 40 xcexcm in 600 dpi printers. These small dimensions require inks that do not plug the small openings. The sizes of the polymer particles are preferably within the range of 50-500 nm and most preferably within the range of 150-300 nm.
In addition, the identity, length, weight and distribution of the hydrophobic groups in the polymer particles must be controlled to insure that these amphipathic polymer particles, acting as a dispersant in a ink composition, fully cover any water-insoluble pigment particles and create an electrostatic layer that prevents aggregation. Otherwise, the amphipathic particles may act as a flocculent.
Control over the particle size and the identity, length, weight and distribution of the hydrophobic groups is permitted by using Atom Transfer Radical Polymerization (ATRP) as the first step in the synthesis. ATRP is a relatively new method for preparing well-defined polymers and copolymers. ATRP is described, inter alia, in the following publications: U.S. Pat. Nos. 6,162,882; 6,124,411; 6,121,371; 6,111,022; 6,071,980; 5,945,491; 5,807,937; and 5,789,487. These patent descriptions of ATRP are hereby incorporated by reference. To date, the ATRP process has not been employed to synthesize dispersants for aqueous inks.
Briefly speaking, ATRP is a controlled, xe2x80x9clivingxe2x80x9d polymerization based on the use of radical polymerization to convert monomers to polymers. The control of the polymerization afforded by ATRP is a result of the formation of radicals that can grow, but are reversibly deactivated to form dormant species. Reactivation of the dormant species allows for the polymer chains to grow again, only to be deactivated later. Such a process results in a polymer chain that slowly, but steadily, grows and has a well-defined end group. The polymerization is characterized by initiation where one initiator molecule generates, at most, one polymer chain and that all polymer chains grow at nearly the same time in the presence of a catalyst. This results in polymers whose average molecular weight is defined by the concentrations and the molecular weights of the initiator and the monomer.
The initiator is generally a simple alkyl halide. The catalyst is a transition metal that is completed by one or more ligands; the catalyst does not need to be used in a one-to-one ratio with the initiator but can be used in much smaller amounts. The deactivator can be formed in situ, or for better control, a small amount (relative to the catalyst) can be added.
The polymeric particles of the present invention may be prepared by a process employing the ATRP. The process comprises the following three steps:
(1) Primary ATRP of Hydrophilic Monomers in an Aqueous Solution
ATRP initiates controlled radical polymerization by reaction of an initiator and a water-soluble monomer in the presence of a transition metal and a ligand. The initiator can be any molecule containing a radically transferable atom or group. A preferred initiator is alkyl halide. The water-soluble monomers can be any hydrophilic monomers described above and are preferably poly ethylene glycol, acrylate, acrylate methylcarboxylate, styrene sulfonates, acrylate dye having sulfonate or carboxylate groups, and mixtures thereof.
The transition metal can be any transition metal or metal compound that is initially in a lower oxidation state or is reduced to the lower oxidation state in early stages of the reaction. The metal may be, but is not limited to, Cu1+, Cu2+, Cu0, Fe2+, Fe3+, Fe0, Ru2+, Ru3+, Ru0, Cr2+, Cr3+, Cr0, Mo2+, Mo3+, Mo0, W2+, W3+, Mn3+, Mn4+, Mn0, Rh3+, Rh4+, Rh0, Re2+, Re3+, Re0, Pd2+, Pd0, Ni2+, Ni3+, Ni0, Co1+, Co2+, V2+, V3+, Zn1+, Zn2+, Au1+, Au2+, Ag1+ and Ag2+; preferred metals are Cu1+, Fe2+, Ru2+, Ni2+. Preferred metal compounds include Cu(I)Br, Cu(I)Cl, Cu(I)triflate, and Cu(II)triflate.
Preferred ligands include 2,2xe2x80x2-bipyridyl(bpy), 4,4xe2x80x2-di(t-butyl)-2,2xe2x80x2-bipyridyl(dTbpy), N,N,Nxe2x80x2,Nxe2x80x3,Nxe2x80x3-pentamethyldiethylenetriamine (PMDETA), tris(2-dimethylaminoethyl)amine (TREN-Me), 4,4xe2x80x2-di(5-nonyl)-2,2xe2x80x2-bipyridyl (dNbpy), 4,4xe2x80x2-dialkyl-2,2xe2x80x2-bipyridyl (dAbpy, a mixture of 5-nonyl and n-pentyl alkyl chains), bis(2-bipyridylmethyl)octylamine and 4,4xe2x80x2,4xe2x80x3-tris(5-nonyl)-2,2xe2x80x2,6xe2x80x2,2xe2x80x3-terpyridyl. The specific ligand must be chosen to meet the solubility requirements for controlled polymerization imposed by the suspension medium, the initiator, and other catalyst components such as the monomers/oligomers/polymers. Most preferred ligands include bpy, dNbpy, dAbpy, dTbpy, bis(2-pyridylmethyl)octylamine and 4,4xe2x80x2,4xe2x80x3-tris(5-nonyl)-2,2xe2x80x2,6xe2x80x2,2xe2x80x3-terpyridyl.
In the ATRP reaction, almost 90% of the monomers will be consumed within a few hours after the polymerization is initiated. The amount of unreacted monomers may be further reduced by heating with free radical initiators at elevated temperature. The amount of initiator usually accounts for less than 2% of the monomers by weight.
(2) Secondary Polymerization of Hydrophobic Monomers in Emulsion
Monomers with hydrophobic moieties are add at this stage to form block copolymers with the ATRP products. Preferred hydrophobic monomers include methyl methacrylate, butyl methacrylate, hexyl acrylate, ethyl hexylacrylate, styrene, and mixtures thereof. The most preferred hydrophobic monomers include methyl methacrylate, hexyl acrylate and a mixture thereof. The polymerization is usually carried out in emulsion in the presence of a surfactant. Preferred surfactants include dioctyl sulfosuccinate, trimethyl ammonium bromide, and Rhodafac RS710. A cross-linker may be added at this stage to increase the shear stability of the polymers. Preferred cross-linkers include ethylene glycol dimethacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, 3-(acryloyloxy)-2-hydroxypropyl methacrylate, ethyleneglycol dimethacrylamide, or other polymerizable monomers with di- or polyfunctional groups. The reaction mixture is stirred for 24 hours at ambient temperature.
The weight ratio between the hydrophilic monomers in step (1) and the hydrophobic monomers in step (2) is preferably 1:9. When a mixture of methyl methacrylate and hexyl acrylate is used as hydrophobic monomers in step (2), the ratio between the two monomers may very from 2:8 to 8:2, with a preferred ratio of 5:5. The amount of surfactant should be less than 3% of the reaction mixture by weight, and preferably 2% of the reaction mixture by weight. All the manipulations in steps (1) and (2) are carried out under nitrogen atmosphere.
(3) Filtration and Neutralization
The reaction mixture is filtered to remove any precipitates formed during the polymerization. The filtered reaction product is then neutralized (pH 6-8) to obtain stable polymeric particles. The polymeric particles obtained from the above-described process have an average diameter of 50 to 400 nm with a pre-determined structure, a molecular weight range of 20-100 kD, and a polydispersity index of 1-1.2.
Ink Composition Containing Amphipathic Particles as a Dispersant
The present invention also provides an ink composition comprising a vehicle, a colorant, a surfactant, and a polymeric dispersant/binder produced by the side chain conversion method or ATRP method.
The vehicle may be water or a mixture of water and one or more humectants.
The colorant may be pigments or dyes. Pigments are preferred colorants since they are water insoluble. Pigments do not dissolve upon contact with water and/or run when exposed to water. They also provide superior smear resistance and light stability compared to dyes.
The dyes used in the present invention are preferably polymerizable dye monomers. These polymerizable dyes may be incorporated into the amphipathic polymers using the above-described methods. The optical density of the dye is preserved since it lies on the outside of the particle in the water phase. Moreover, the dye itself acts like a stabilizing group for the particles.
The ink may contain as much as 30% colorant by weight, but generally the colorant is in the range of 0.1 to 15% by weight of the total ink composition. Preferably, the colorant represents 0.1 to 8% of the total ink composition.
The amount of surfactant is in the range of 0.01% to 5% by weight, preferably 0.1% to 3% by weight, more preferably 0.5% to 1% by weight.
The surfactant may be an anionic, cationic, amphoteric or nonionic surfactant, or a compatible mixture thereof.
Examples of anionic surfactants are water-soluble soaps or water-soluble synthetic surface active compounds.
Examples of the soaps are unsubstituted or substituted ammonium salts of higher fatty acids (C10-C22), such as the sodium or potassium salts of oleic acid or stearic acid or of natural fatty acid mixtures such as coconut oil or tallow oil, alkali metal salts, alkaline earth metal salts or fatty acid methyllaurin salts.
Examples of synthetic surfactants are alkylarylsulphonates, sulphonated benzimidazole derivatives, fatty alcohol sulphates, or fatty alcohol sulphonates.
Examples of alkylarylsulphonates are the calcium, sodium or triethanolamine salts of dodecylbenzenesulphonic acid, dibutylnaphthalenesulphonic acid, or a condensate of naphthalenesulphonic acid and formaldehyde, or the phosphate salt of the phosphoric acid ester of an adduct of p-nonylphenol with 4 to 14 moles of ethylene oxide.
Examples of sulphonated benzimidazole derivatives are those with at least one sulphonic acid group or one fatty acid radical containing approximately 8 to 22 carbon atoms.
Examples of non-ionic surfactants are polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols having approximately 3 to 30 glycol ether groups and approximately 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moiety; saturated or unsaturated fatty acid and alkylphenols having approximately 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols; water-soluble adducts of polyethylene oxide with ethylenediaminopolypropylene glycol, polypropylene glycol, or alkylpolypropylene glycol having approximately 1 to 10 carbon atoms in the alkyl chain, having approximately 20 to 250 ethylene glycol ether groups and approximately 10 to 100 propylene glycol ether groups in the usual ratio of 1 to 5 ethylene glycol moiety:propylene glycol moiety; fatty acid esters of polyoxyethylene sorbitan such as polyoxyethylene sorbitan trioleate; octylphenoxypolyethoxyethanol; polyethylene glycol; tributylphenoxypolyethyleneethanol; polypropylene/polyethylene oxide adducts; castor oil polyplycol ethers; and nonylphenolpolyethoxyethanols.
Examples of cationic surfactants are quaternary ammonium salts in the form of halides, methylsulphates or ethylsulphates which have as N-substituent at least one C8-C22 alkyl radical or unsubstituted or halogenated lower alkyl or benzyl or hydroxy-lower alkyl radical, such as stearyltrimethylammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.
Examples of amphoteric surfactants are the aminocarboxylic and aminosulphonic acids and salts thereof such as alkali metal 3-(dodecylamino)propionate and alkali metal 3-(dodecylamino)propane-1-sulphonate or alkyl and alkylamido betaines such as cocamidopropyl betaine.
Examples of surfactants which may be used in the combination are surfactants from the Teric.RTM. series such as N4 Teric, Teric BL8, Teric 16A16, Teric PE61, Alkanate 3SL3, N9 Teric, G9 A6 Teric, or surfactants from the Rhodafac.RTM. series such as Rhodafac RA 600. Further examples are Calgon.RTM. (sodium hexametaphosphate), Borax.RTM. (sodium decahydrate borate), soap, sodium lauryl sulphate, or sodium cholate.
The dispersant comprises polymer particles produced by the side chain conversion method or ATRP method. The particles must be small enough to permit free flow of the ink through the ejecting nozzle of an inkjet printer. Ejecting nozzles typically have a diameter ranging from 10 xcexcm to 50 xcexcm. In addition, the polymer size influences the stability of the dispersion, since large particle are more likely to precipitate. Accordingly, the polymer particles have an average diameter of 50 to 500 xcexcm. Ideally, the average particle size is about 300 nm.
The ink may contain as much as 8% dispersant by weight, but generally the dispersant is in the range of 1% to 5% by weight of the total ink composition. Preferably, the dispersant represents 2% to 3% of the total ink composition.
The ink composition may also include UV absorbers, anti oxidants and hindered amines to improve the stability and durability of printed images.
Although preferred embodiments and their advantages have been described in detail, various changes, substitutions and alterations may be made herein without departing from the spirit and scope as defined by the appended claims and their equivalents.

Amphipathic polymer particles and methods of manufacturing the same

Hewlett-Packard Development Company, L.P.


Thermoplastic molding compositions comprise

The invention further relates to the use of the novel molding compositions for producing fibers, films or moldings, and also to the resultant moldings of any type.
The market is increasingly interested in halogen-free flame-retardant polyesters. Significant requirements placed upon the flame retardant are: pale intrinsic color, adequate heat stability for incorporation into thermoplastics, and also effectiveness in reinforced and unreinforced polymer (wicking effect of glass fibers).
The UL 94 fire test for unreinforced polyesters should be passed here at the V-0 level. For reinforced polyesters, at least the V-2 classification should be obtained and/or the glow-wire test passed.
Besides halogen-containing systems there are in principle four halogen-free FR systems used in thermoplastics:
Inorganic flame retardants, which have to be used in large amounts to be effective.
Nitrogen-containing FR systems, such as melamine cyanurate, which has limited effectiveness in thermoplastics, e.g. polyamide. In reinforced polyamide it is effective only in combination with shortened glass fibers. Melamine cyanurate by itself is not effective in polyesters.
Phosphorus-containing FR systems, which are generally not very effective in polyesters.
Phosphorus/nitrogen-containing FR systems, such as ammonium polyphosphates or melamine phosphates, which do not have sufficient thermal stability for thermoplastics processed at temperatures above 200xc2x0 C.
JP-A 03/281 652 has disclosed polyalkylene terephthalates which comprise melamine cyanurate and glass fibers, and also a phosphorus-containing flame retardant. These molding compositions comprise derivatives of phosphoric acid, such as phosphoric esters (valence state +5), which tend to bleed out on exposure to heat.
These disadvantages are also seen for the combination of melamine cyanurate (MC) with resorcinol bis(diphenyl phosphate), known from JP-A 05/070 671. These molding compositions also have high phenol values during processing and do not have adequate mechanical properties.
JP-A 09/157 503 has disclosed polyester molding compositions with MC, phophorus compounds and lubricants, comprising less than 10% of reinforcing agents. Molding compositions of this type have flame-retardant and mechanical properties which are not fully satisfactory. The same applies to migration and phenol formation during processing.
EP-A 699 708 and BE-A 875 530 have disclosed salts of phosphinic acid as flame retardants for polyesters.
WO 97/05705 has disclosed combinations of MC with phosphorus-containing compounds and lubricants for polyesters.
It is an object of the present invention to provide flame-retardant polyester molding compositions which achieve an adequate UL 94 classification and pass the glow-wire test. At the same time, mold deposit should be minimized and flowability during processing should be improved.
We have found that this object is achieved by means of the thermoplastic molding compositions defined at the outset. Preferred embodiments are given in the subclaims.
The novel molding compositions comprise, as component (A), from 5 to 96% by weight, preferably from 10 to 70% by weight and in particular from 10 to 60% by weight, of a thermoplastic polyester.
Use is generally made of polyesters based on aromatic dicarboxylic acids and on an aliphatic or aromatic dihydroxy compound.
A first group of preferred polyesters is that of polyalkylene terephthalates having from 2 to 10 carbon atoms in the alcohol moiety.
Polyalkylene terephthalates of this type are known per se and are described in the literature. Their main chain contains an aromatic ring which derives from the aromatic dicarboxylic acid. There may also be substitution in the aromatic ring, e.g. by halogen, such as chlorine or bromine, or by C1-C4-alkyl, such as methyl, ethyl, iso- or n-propyl, or n-, iso- or tert-butyl.
These polyalkylene terephthalates may be prepared by reacting aromatic dicarboxylic acids, or their esters or other ester-forming derivatives, with aliphatic dihydroxy compounds in a manner known per se.
Preferred dicarboxylic acids are 2,6-naphthalenedicarboxylic acid, terephthalic acid and isophthalic acid, and mixtures of these. Up to 30 mol %, preferably not more than 10 mol %, of the aromatic dicarboxylic acids may be replaced by aliphatic or cycloaliphatic dicarboxylic acids, such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acids or cyclohexanedicarboxylic acids.
Preferred aliphatic dihydroxy compounds are diols having from 2 to 6 carbon atoms, in particular 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and neopentyl glycol, and mixtures of these.
Particularly preferred polyesters (A) are polyalkylene terephthalates derived from alkanediols having from 2 to 6 carbon atoms. Among these, particular preference is given to polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate, and mixtures of these. Preference is also given to PET and/or PBT which comprise, as further monomer units, up to 1% by weight, preferably up to 0.75% by weight, of 1,6-hexanediol and/or 5-methyl-1,5-pentanediol.
The viscosity number of the polyesters (A) is generally in the range from 50 to 220, preferably from 80 to 160 (measured in 0.5% strength by weight solution in a phenol/o-dichlorobenzene mixture with a weight ratio of 1:1 at 25xc2x0 C.) in accordance with ISO 1628.
Particular preference is given to polyesters whose carboxyl end group content is up to 100 mval/kg of polyester, preferably up to 50 mval/kg of polyester and in particular up to 40 mval/kg of polyester. Polyesters of this type may be prepared, for example, by the process of DE-A 44 01 055. The carboxyl end group content is usually determined by titration methods (e.g. potentiometry).
Particularly preferred molding compositions comprise, as component A), a mixture of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). The proportion of the polyethylene terephthalate in the mixture is preferably up to 50% by weight, in particular from 10 to 30% by weight, based on 100% by weight of A).
Novel molding compositions of this type have very good flame-retardant properties and improved mechanical properties.
It is also advantageous to use recycled PET materials (also termed scrap PET) in a mixture with polyalkylene terephthalates, such as PBT.
Recycled materials are generally:
1) those known as post-industrial recycled materials: these are production wastes from polycondensation or from processing, e.g. sprues from injection molding, start-up material from injection molding or extrusion, or edge trims from extruded sheets or films.
2) Post-consumer recycled materials: these are plastic items which are collected and treated after utilization by the end consumer. Blow-molded PET bottles for mineral water, soft drinks and juices are easily the predominant items in quantity terms.
Both types of recycled material may be used either in ground or pellet form. In the latter case, the crude recycled materials are isolated and purified, and then melted and pelletized using an extruder. This usually facilitates handling and free flow, and also metering for further steps in processing.
The recycled materials used may either be pellets or regrind. The edge length should not be more than 6 mm, preferably less than 5 mm.
Because polyesters undergo hydrolytic cleavage during processing (due to traces of moisture) it is advisable to predry the recycled material. The residual moisture after drying is preferably from 0.01 to 0.7%, in particular from 0.2 to 0.6%.
Another class to be mentioned is that of fully aromatic polyesters deriving from aromatic dicarboxylic acids and aromatic dihydroxy compounds.
Suitable aromatic dicarboxylic acids are the compounds previously mentioned for the polyalkylene terephthalates. The mixtures preferably used are made from 5 to 100 mol % of isophthalic acid and from 0 to 95 mol % of terephthalic acid, in particular from about 50 to about 80% of terephthalic acid and from 20 to about 50% of isophthalic acid.
The aromatic dihydroxy compounds preferably have the formula
where Z is alkylene or cycloalkylene having up to 8 carbon atoms, arylene having up to 12 carbon atoms, carbonyl, sulfonyl, oxygen or sulfur or a chemical bond, and m is from 0 to 2. The phenylene groups in the compounds may also have substitution by C1-C6-alkyl or alkoxy, and fluorine, chlorine or bromine.
Examples of parent compounds for these compounds are
Dihydroxydiphenyl,
Di(hydroxyphenyl)alkane,
Di(hydroxyphenyl)cycloalkane,
Di(hydroxyphenyl) sulfide,
Di(hydroxyphenyl) ether,
Di(hydroxyphenyl) ketone,
Di(hydroxyphenyl) sulfoxide,
xcex1,xcex1xe2x80x2-di(hydroxyphenyl)dialkylbenzene,
Di(hydroxyphenyl) sulfone, di(hydroxybenzoyl)benzene,
resorcinol, and
hydroquinone, and also the ring-alkylated and ring-halogenated derivatives of these.
Among these, preference is given to
4,4xe2x80x2-Dihydroxydiphenyl,
2,4-Di(4xe2x80x2-hydroxyphenyl)-2-methylbutane
xcex1,xcex1xe2x80x2-Di(4-hydroxyphenyl)-p-diisopropylbenzene,
2,2-Di(3xe2x80x2-methyl-4xe2x80x2-hydroxyphenyl)propane and
2,2-Di(3xe2x80x2-chloro-4xe2x80x2-hydroxyphenyl)propane,
and in particular to
2,2-Di(4xe2x80x2-hydroxyphenyl)propane
2,2-Di(3xe2x80x2,5-dichlorodihydroxyphenyl)propane,
1,1-Di(4xe2x80x2-hydroxyphenyl)cyclohexane,
3,4xe2x80x2-Dihydroxybenzophenone,
4,4xe2x80x2-Dihydroxydiphenyl sulfone, and
2,2-Di(3xe2x80x2,5xe2x80x2-dimethyl-4xe2x80x2-hydroxyphenyl)propane,
or mixtures of these.
It is, of course, also possible to use mixtures of polyalkylene terephthalates and fully aromatic polyesters. These generally comprise from 20 to 98% by weight of the polyalkylene terephthalate and from 2 to 80% by weight of the fully aromatic polyester.
For the purposes of the present invention, polyesters include polycarbonates which have been obtained by polymerizing aromatic dihydroxy compounds, in particular 2,2-bis(4-hydroxyphenyl)-propane (bisphenol A) or its derivatives, e.g. with phosgene. Corresponding products are known per se and are described in the literature, and many of them are also commercially available. The amount of the polycarbonates is up to 90% by weight, preferably up to 50% by weight, based on 100% by weight of component (A).
It is, of course, also possible to use polyester block copolymers, such as copolyetheresters. Products of this type are known per se and are described in the literature, e.g. in U.S. Pat. No. 3,651,014. Corresponding products are also available commercially, e.g. Hytrel(copyright) (DuPont).
The novel molding compositions comprise, as component B), from 0.1 to 30% by weight, preferably from 1 to 25% by weight and in particular from 10 to 20% by weight, of a phosphinate of formula (I) and/or a diphosphinate of formula (II) and/or polymers of these
where:
R1 and R2 are hydrogen or C1-C6-alkyl, preferably C1-C4-alkyl, linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl or n-pentyl; phenyl; where preferably at least one of the radicals R1 and R2 is hydrogen and in particular R1 and R2 are hydrogen;
R3 is C1-C10-alkylene, linear or branched, e.g. methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene or n-dodecylene; arylene, e.g. phenylene or naphthylene; alkylarylene, e.g. methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene or tert-butylnaphthylene; arylalkylene, e.g. phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene;
M is an alkaline-earth or alkali metal, Al, Zn, Fe or B,
m is an integer from 1 to 3;
n is an integer from 1 to 3, and
x is 1 or 2.
Particular preference is given to compounds of formula II where R1 and R2 are hydrogen, where M is preferably Zn or Al, and particular preference is given to calcium phosphinate.
Products of this type are available commercially, for example as calcium phosphinate.
Examples of suitable salts of formula I or II where only one of R1 and R2 is hydrogen are salts of phenylphosphinic acid, preference being given to its Na and/or Ca salts.
Suitable organic phosphorus-containing flame retardants C) are present in the novel molding compositions in amounts of from 1 to 30% by weight, preferably from 1 to 25% by weight, and in particular from 5 to 20% by weight, based on the total weight of components A) to E).
Organic phosphorus-containing compounds for component C) have phosphorus in a valence state of from xe2x88x923 to +5. For the purposes of the invention the valence state is the oxidation state as given in Lehrbuch der Anorganischen Chemie, by A. F. Hollemann and E. Wiberg, Walter des Gruyter and Co. (1964, 57th to 70th edition), pages 166-177. Phosphorus compounds of the valence states from xe2x88x923 to +5 derive from phosphine (xe2x88x923), diphosphine (xe2x88x922), phosphine oxide (xe2x88x921), elemental phosphorus (+0), hypophosphorous acid (+1), phosphorous acid (+3), hypodiphosphoric acid (+4) and phosphoric acid (+5).
Only a few examples will be mentioned from the large number of phosphorus-containing compounds.
Examples of phosphorus compounds of the phosphine class, having the valence state xe2x88x923, are aromatic phosphines, such as triphenylphosphine, tritolylphosphine, trinonylphosphine, trinaphthylphosphine, etc. Triphenylphosphine is particularly suitable.
Examples of phosphorus compounds of the diphosphine class, having the valence state xe2x88x922, are tetraphenyldiphosphine, tetranaphthyldiphosphine, etc. Tetranaphthyldiphosphine is particularly suitable.
Phosphorus compounds of the valence state xe2x88x921 derive from phosphine oxide.
Suitable compounds are phosphine oxides of formula III
where R1, R2 and R3 are identical or different and are alkyl, aryl, alkylaryl or cycloalkyl having from 8 to 40 carbon atoms.
Examples of phosphine oxides are triphenylphosphine oxide, tritolylphosphine oxide, trisnonylphenylphosphine oxide, tricyclohexylphosphine oxide, tris(n-butyl)phosphine oxide, tris(n-hexyl)phosphine oxide, tris(n-octyl)phosphine oxide, tris(cyanoethyl)phosphine oxide, benzylbis(cyclohexyl)phosphine oxide, benzylbisphenylphosphine oxide and phenylbis(n-hexyl)phosphine oxide. Other preferred compounds are oxidized reaction products of phosphine and aldehydes, in particular from tert-butylphosphine with glyoxal. Particular preference is given to the use of triphenylphosphine oxide, tricyclohexylphosphine oxide or tris(n-octyl)phosphine oxide.
Other suitable compounds are triphenylphosphine sulfide and its derivatives as described above for phosphine oxides and triphenyl phosphate.
Examples of phosphorus compounds of the oxidation state +1 are hypophosphites, e.g. organic hypophosphites, such as cellulose hypophosphite esters, esters of hypophosphorous acids with diols, e.g. that of 1,10-dodecanediol. It is also possible to use substituted phosphinic acids and anhydrides of these, e.g. diphenylphosphinic acid. Other possible compounds are di-p-tolylphosphinic acid and dicresylphosphinic anhydride. Compounds such as the bis(diphenylphosphinic)esters of hydroquinone, ethylene glycol and propylene glycol, inter alia, may also be used. Other suitable compounds are aryl(alkyl)phosphinamides, such as the dimethylamide of diphenylphosphinic acid, and sulfonamidoaryl(alkyl)phosphinic acid derivatives, such as p-tolylsulfonamidodiphenylphosphinic acid. Preference is given to the use of the bis(diphenylphosphinic)esters of hydroquinone and ethylene glycol and of the bis(diphenylphosphinate) of hydroquinone.
Phosphorus compounds of the oxidation state +3 derive from phosphorous acid. Suitable compounds are cyclic phosphonates which derive from pentaerythritol, from neopentyl glycol or from pyrocatechol, e.g.
where R is C1-C4-alkyl, preferably methyl, and X is 0 or 1 (Amgard(copyright) P45 from Albright and Wilson).
Phosphorus of the valence state +3 is also present in triaryl(alkyl) phosphites, such as triphenyl phosphite, tris(4-decylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite and phenyl didecyl phosphite. It is also possible to use diphosphites, such as propylene glycol 1,2-bis(diphosphite) or cyclic phosphites which derive from pentaerythritol, from neopentylglycol or from pyrocatechol.
Particular preference is given to neopentyl glycol methylphosphonate and methyl neopentyl glycol phosphite, and also to pentaerythritol dimethyldiphosphonate and dimethyl pentaerythritol diphosphite.
Phosphorus compounds of oxidation state +4 which may be used are particularly hypodiphosphates, such as tetraphenyl hypodiphosphate and bisneopentyl hypodiphosphate.
Phosphorus compounds of oxidation state +5 which may be used are particularly alkyl- and aryl-subsituted phosphates. Examples of these are phenyl bisdodecyl phosphate, phenyl ethyl hydrogen phosphate, phenyl bis(3,5,5-trimethylhexyl) phosphate, ethyl diphenyl phosphate, 2-ethylhexyl ditolyl phosphate, diphenyl hydrogen phosphate, bis(2-ethylhexyl) p-tolyl phosphate, tritolyl phosphate, bis(2-ethylhexyl) phenyl phosphate, di(nonyl) phenyl phosphate, phenyl methyl hydrogenphosphate, di(dodecyl) p-tolyl phosphate, p-tolylbis(2,5,5-trimethylhexyl) phosphate and 2-ethylhexyl diphenyl phosphate. Particularly suitable phosphorus compounds are those in which each radical is aryloxy. Very particularly suitable compounds are triphenyl phosphate and resorcinol bis(diphenyl phosphate) and its ring-substituted derivatives of formula IV (RDPs):
where:
R4 to R7 are aromatic radicals having from 6 to 20 carbon atoms, preferably phenyl, which may have substitution by alkyl groups having from 1 to 4 carbon atoms, preferably methyl,
R8 is a bivalent phenol radical, preferably
and n is an average value of from 0.1 to 100, preferably from 0.5 to 50, in particular from 0.8 to 10 and very particularly from 1 to 5.
Due to the process used for their manufacture, RDP products available commercially under the tradename Fyroflex(copyright)-RDP (Akzo Nobel) and also CR 733-S (Daihachi) are mixtures of about 85% of RDP with about 2.5% of triphenyl phosphate and also about 12.5% of oligomeric fractions in which the degree of oligomerization is mostly less than 10.
It is also possible to use cyclic phosphates. Of these, diphenyl pentaerythritol diphosphate and phenyl neopentyl phosphate are particularly suitable.
Besides the low-molecular-weight phosphorus compounds mentioned above, it is also possible to use oligomeric or polymeric phosphorus compounds.
Polymeric, halogen-free organic phosphorus compounds of this type with phosphorus in the polymer chain are produced, for example, in the preparation of pentacyclic unsaturated phosphine dihalides, as described, for example, in DE-A 20 36 173. The molecular weight of these polyphospholine oxides, measured by vapor-pressure osmometry in dimethylformamide, should be in the range from 500 to 7000, preferably from 700 to 2000.
The phosphorus here has the oxidation state xe2x88x921.
It is also possible to use inorganic coordination polymers of aryl(alkyl)phosphinic acids, such as poly-xcex2-sodium(I) methylphenylphosphinate. Their preparation is given in DE-A 31 40 520. The phosphorus has the oxidation number +1.
Halogen-free polymeric phosphorus compounds of this type may also be produced by the reaction of a phosphonic acid chloride, such as phenyl-, methyl-, propyl-, styryl- or vinylphosphonyl dichloride, with dihydric phenols, such as hydroquinone, resorcinol, 2,3,5-trimethylhydroquinone, bisphenol A or tetramethylbisphenol A.
Other halogen-free polymeric phosphorus compounds which may be present in the novel molding compositions are prepared by reacting phosphorus oxytrichloride or phosphoric ester dichlorides with a mixture of mono-, di- or trihydric phenols and other compounds carrying hydroxyl groups (cf. Houben-Weyl-Muller, Thieme-Verlag Stuttgart, Organische Phosphorverbindungen Part II (1963)). It is also possible to produce polymeric phosphonates via transesterification reactions of phosphonate esters with dihydric phenols (cf. DE-A 29 25 208) or via reactions of phosphonate esters with diamines, or with diamides or hydrazides (cf. U.S. Pat. No. 4,403,075). The inorganic compound poly(ammonium phosphate) may also be used.
It is also possible to use oligomeric pentaerythritol phosphites, pentaerythritol phosphates and pentaerythritol phosphonates, as in EP-B 8 486, for example Mobil Antiblaze(copyright) 19 (registered trademark of Mobil Oil).
The novel molding compositions may comprise, as component D), from 0 to 5% by weight, preferably from 0.05 to 3% by weight, and in particular from 0.1 to 2% by weight, of at least one ester or amide of saturated or unsaturated aliphatic carboxylic acids having from 10 to 40 carbon atoms, preferably from 16 to 22 carbon atoms, with saturated aliphatic alcohols or amines having from 2 to 40 carbon atoms, preferably from 2 to 6 carbon atoms.
The carboxylic acids may be mono- or dibasic. Examples which may be mentioned are pelargonic acid, palmitic acid, lauric acid, margaric acid, dodecanedioic acid, behenic acid and, particularly preferably, stearic acid, capric acid and montanic acid (a mixture of fatty acids having from 30 to 40 carbon atoms).
The aliphatic alcohols may be mono- to tetrahydric. Examples of alcohols are n-butanol, n-octanol, stearyl alcohol, ethylene glycol, propylene glycol, neopentyl glycol and pentaerythritol. Glycerol and pentaerythritol are preferred.
The aliphatic amines may be mono- to tribasic. Examples of these are stearylamine, ethylenediamine, propylendiamine, hexamethylenediamine and di(6-aminohexyl)amine. Ethylenediamine and hexamethylenediamine are particularly preferred. Correspondingly, preferred esters or amides are glycerol distearate, glycerol tristearate, ethylenediammonium distearate, glycerol monopalmitate, glycerol trilaurate, glycerol monobehenate and pentaerythritol tetrastearate.
It is also possible to use mixtures of different esters or amides or combinations of esters with amides. The mixing ratio may be as desired.
The novel molding compositions may comprise, as component E), from 0 to 60% by weight, in particular up to 50% by weight, of other additives.
Examples of usual additives E) are amounts of up to 40% by weight, preferably up to 30% by weight, of elastomeric polymers (also frequently termed impact modifiers, elastomers or rubbers).
These are very generally copolymers which have preferably been built up from at least two of the following monomers: ethylene, propylene, butadiene, isobutene, isoprene, chloroprene, vinyl acetate, styrene, acrylonitrile and acrylates and/or methacrylates having from 1 to 18 carbon atoms in the alcohol component.
Polymers of this type have been described, for example, in Houben-Weyl, Methoden der organischen Chemie, Vol. 14/1 (Georg-Thieme-Verlag, Stuttgart, 1961), pp. 392-406 and in the monograph by C. B. Bucknall, xe2x80x9cToughened Plasticsxe2x80x9d (Applied Science Publishers, London, 1977).
Some preferred types of such elastomers are described below.
Preferred types of such elastomers are those known as ethylene-propylene (EPM) and ethylene-propylene-diene (EPDM) rubbers.
EPM rubbers generally have practically no residual double bonds, whereas EPDM rubbers may have from 1 to 20 double bonds per 100 carbon atoms.
Examples of diene monomers for EPDM rubbers are conjugated dienes, such as isoprene and butadiene, nonconjugated dienes having from 5 to 25 carbon atoms, such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene and 1,4-octadiene, cyclic dienes, such as cyclopentadiene, cyclohexadienes, cyclooctadienes and dicyclopentadiene, and also alkenylnorbornenes, such as 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 2-methallyl-5-norbornene and 2-isopropenyl-5-norbornene, and tricyclodienes, such as 3-methyl-tricyclo[5.2.1.02,6]-3,8-decadiene, or mixtures of these. Preference is given to 1,5-hexadiene, 5-ethylidenenorbornene and dicyclopentadiene. The diene content of the EPDM rubbers is preferably from 0.5 to 50% by weight, in particular from 1 to 8% by weight, based on the total weight of the rubber.
EPM and EPDM rubbers may preferably also have been grafted with reactive carboxylic acids or with derivatives of these. Examples of these are acrylic acid, methacrylic acid and derivatives thereof, e.g. glycidyl (meth)acrylate, and also maleic anhydride.
Copolymers of ethylene with acrylic acid and/or methacrylic acid and/or with the esters of these acids are another group of preferred rubbers. The rubbers may also include dicarboxylic acids, such as maleic acid and fumaric acid, or derivatives of these acids, e.g. esters and anhydrides, and/or monomers containing epoxy groups. These dicarboxylic acid derivatives and/or monomers containing epoxy groups are preferably incorporated into the rubber by adding, to the monomer mixture, monomers containing dicarboxylic acid groups and/or epoxy groups and having the formula I, II, III or IV
where R1 to R9 are hydrogen or alkyl having from 1 to 6 carbon atoms, and m is an integer from 0 to 20, g is an integer from 0 to 10 and p is an integer from 0 to 5.
R1 to R9 are preferably hydrogen, where m is 0 or 1 and g is 1. The corresponding compounds are maleic acid, fumaric acid, maleic anhydride, allyl glycidyl ether and vinyl glycidyl ether.
Preferred compounds of the formulae I, II and IV are maleic acid, maleic anhydride and (meth)acrylates containing epoxy groups, such as glycidyl acrylate and glycidyl methacrylate, and the esters with tertiary alcohols, such as tert-butyl acrylate. Although the latter have no free carboxyl groups their behavior approximates to that of the free acids and they are therefore termed monomers with latent carboxyl groups.
The copolymers are advantageously composed of from 50 to 98% by weight of ethylene, from 0.1 to 20% by weight of monomers containing epoxy groups and/or methacrylic acid and/or monomers containing anhydride groups, the remaining amount being (meth)acrylates.
Particular preference is given to copolymers made from
from 50 to 98% by weight, in particular from 55 to 95% by weight, of ethylene,
from 0.1 to 40% by weight, in particular from 0.3 to 20% by weight, of glycidyl acrylate and/or glycidyl methacrylate, (meth)acrylic acid and/or maleic anhydride, and
from 1 to 45% by weight, in particular from 10 to 40% by weight, of n-butyl acrylate and/or 2-ethylhexyl acrylate.
Other preferred (meth)acrylates are the methyl, ethyl, propyl, isobutyl and tert-butyl esters.
Besides these, comonomers which may be used are vinyl esters and vinyl ethers.
The ethylene copolymers described above may be prepared by processes known per se, preferably by random copolymerization at high pressure and elevated temperature. Appropriate processes are well known.
Preferred elastomers also include emulsion polymers whose preparation is described, for example, by Blackley in the monograph xe2x80x9cEmulsion Polymerizationxe2x80x9d. The emulsifiers and catalysts which may be used are known per se.
In principle it is possible to use homogeneously structured elastomers or those with a shell construction. The shell-type structure is a result of the sequence of addition of the individual monomers. The morphology of the polymers is also affected by this sequence of addition.
Monomers which may be mentioned here, merely as examples, for the preparation of the rubber fraction of the elastomers are acrylates, such as n-butyl acrylate and 2-ethylhexyl acrylate, and corresponding methacrylates, and butadiene and isoprene, and also mixtures of these. These monomers may be copolymerized with other monomers, such as styrene, acrylonitrile or with vinyl ethers and with other acrylates or methacrylates, such as methyl methacrylate, methyl acrylate, ethyl acrylate or propyl acrylate.
The soft or rubber phase (with a glass transition temperature of below 0xc2x0 C.) of the elastomers may be the core, the outer shell or an intermediate shell (in the case of elastomers whose structure has more than two such layers). Elastomers having more than one shell may also have more than one shell made from a rubber phase.
If one or more hard components (with glass transition temperatures above 20xc2x0 C.) are involved, besides the rubber phase, in the structure of the elastomer, these are generally prepared by polymerizing, as principal monomers, styrene, acrylonitrile, methacrylonitrile, xcex1-methylstyrene, p-methylstyrene or acrylates or methacrylates, such as methyl acrylate, ethyl acrylate or methyl methacrylate. Besides these, it is also possible to use relatively small proportions of other comonomers.
It has proven advantageous in some cases to use emulsion polymers which have reactive groups at their surfaces. Examples of groups of this type are epoxy, carboxyl, latent carboxyl, amino and amide groups, and also functional groups which may be introduced by concomitant use of monomers of the formula
where:
R10 is hydrogen or C1-C4-alkyl,
R11 is hydrogen or C1-C8-alkyl or aryl, in particular phenyl,
R12 is hydrogen, C1-C10-alkyl, C6-C12-aryl or xe2x80x94OR13,
R13 is C1-C8-alkyl or C6-C12-aryl, if desired with substitution by Oxe2x80x94 or N-containing groups,
X is a chemical bond or C1-C10-alkylene or C6-C12-arylene, or
Y is Oxe2x80x94Z or NHxe2x80x94Z, and
Z is C1-C10-alkylene or C6-C12-arylene.
The graft monomers described in EP-A 208 187 are also suitable for introducing reactive groups at the surface.
Other examples which may be mentioned are acrylamide, methacrylamide and substituted acrylates or methacrylates, such as (N-tert-butylamino)ethyl methacrylate,
(N,N-dimethylamino)ethyl acrylate, (N,N-dimethylamino)methyl acrylate and (N,N-diethylamino)ethyl acrylate.
The particles of the rubber phase may also have been crosslinked. Examples of crosslinking monomers are 1,3-butadiene, divinylbenzene, diallyl phthalate and dihydrodicyclopentadienyl acrylate, and also the compounds described in EP-A 50 265.
It is also possible to use the monomers known as graft-linking monomers, i.e. monomers having two or more polymerizable double bonds which react at different rates during the polymerization. Preference is given to the use of compounds of this type in which at least one reactive group polymerizes at about the same rate as the other monomers, while the other reactive group (or reactive groups), for example, polymerize(s) significantly more slowly. The different polymerization rates give rise to a certain proportion of unsaturated double bonds in the rubber. If another phase is then grafted onto a rubber of this type, at least some of the double bonds present in the rubber react with the graft monomers to form chemical bonds, i.e. the phase grafted on has at least some degree of chemical bonding to the graft base.
Examples of graft-linking monomers of this type are monomers containing allyl groups, in particular allyl esters of ethylenically unsaturated carboxylic acids, for example allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate and diallyl itaconate, and the corresponding monoallyl compounds of these dicarboxylic acids. Besides these there is a wide variety of other suitable graft-linking monomers. For further details reference may be made here, for example, to U.S. Pat. No. 4,148,846.
The proportion of these crosslinking monomers in the impact-modifying polymer is generally up to 5% by weight, preferably not more than 3% by weight, based on the impact-modifying polymer.
Some preferred emulsion polymers are listed below. Mention is made firstly of graft polymers with a core and at least one outer shell and the following structure:
These graft polymers, in particular ABS and/or ASA polymers, are used in amounts of up to 40% by weight in particular for the impact-modification of PBT, if desired in a mixture with up to 40% by weight of polyethylene terephthalate. Corresponding blend products are commercially available under the tradename Ultradur(copyright)S (previously Ultrablend(copyright)S from BASF AG). ABS/ASA mixtures with polycarbonates are available commercially under the trademark Terblend(copyright) (BASF AG).
Instead of graft polymers whose structure has more than one layer of this type it is also possible to use homogeneous elastomers, i.e. those having a single layer and made from 1,3-butadiene, isoprene and n-butyl acrylate or from copolymers of these. These products, too, may be prepared with concomitant use of crosslinking monomers or of monomers having reactive groups.
Examples of preferred emulsion polymers are n-butyl acrylate-(meth)acrylic acid copolymers, n-butyl acrylate-glycidyl acrylate or n-butyl acrylate-glycidyl methacrylate copolymers, graft polymers with an inner core made from n-butyl acrylate or based on butadiene and with an outer shell made from the abovementioned copolymers, and copolymers of ethylene with comonomers which supply reactive groups.
The elastomers described may also be prepared by other conventional processes, e.g. by suspension polymerization.
Preference is also given to silicone rubbers, as described in DE-A 37 25 576, EP-A 235 690, DE-A 38 00 603 and EP-A 319 290.
It is, of course, also possible to use mixtures of the types of rubbers listed above.
Fibrous or particulate fillers which may be mentioned are carbon fibers, glass fibers, glass beads, amorphous silica, asbestos, calcium silicate, calcium metasilicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica, barium sulfate and feldspar, used in amounts of up to 50% by weight, in particular from 1 to 40% by weight, particularly from 20 to 35% by weight.
Examples of preferred fibrous fillers are carbon fibers, aramid fibers and potassium titanate fibers, and particular preference is given to glass fibers in the form of E glass. These may be used as rovings or in the commercially available forms of chopped glass.
The fibrous fillers may have been surface-precoated with a silane compound to improve compatibility with the thermoplastic.
Suitable silane compounds have the formula:
(Xxe2x80x94(CH2)n)kxe2x80x94Sixe2x80x94(Oxe2x80x94CmH2m+1)4xe2x88x92k
where:
n is an integer from 2 to 10, preferably 3 or 4,
m is an integer from 1 to 5, preferably 1 or 2, and
k is an integer from 1 to 3, preferably 1.
Preferred silane compounds are aminopropyltrimethoxysilane, aminobutyltrimethoxysilane, aminopropyltriethoxysilane and aminobutyltriethoxysilane, and also the corresponding silanes which contain a glycidyl group as substituent X.
The silane compounds are generally used for surface coating in amounts of from 0.05 to 5% by weight, preferably from 0.5 to 1.5% by weight and in particular from 0.8 to 1% by weight (based on D).
Acicular mineral fillers are also suitable.
For the purposes of the present invention, acicular mineral fillers are mineral fillers with pronounced acicular character. An example is acicular wollastonite. The mineral preferably has an L/D (length to diameter) ratio of from 8:1 to 35:1, preferably from 8:1 to 11:1. The mineral filler may, if desired, have been pretreated with the abovementioned silane compounds, but the pretreatment is not essential.
Other fillers which may be mentioned are kaolin, calcined kaolin, wollastonite, talc and chalk.
The novel thermoplastic molding compositions may comprise, as component E), conventional processing aids, such as stabilizers, oxidation inhibitors, agents to prevent decomposition by heat or by ultraviolet light, lubricants, mold-release agents, colorants, such as dyes and pigments, nucleating agents, plasticizers, etc.
Examples of oxidation inhibitors and heat stabilizers are sterically hindered phenols and/or phosphites, hydroquinones, aromatic secondary amines, such as diphenylamines, various substituted representatives of these groups and mixtures of these in concentrations of up to 1% by weight, based on the weight of the thermoplastic molding compositions.
UV stabilizers which may be mentioned and which are usually used in amounts of up to 2% by weight, based on the molding composition, are various substituted resorcinols, salicylates, benzotriazoles and benzophenones.
Colorants which may be added are inorganic pigments, such as titanium dioxide, ultramarine blue, iron oxide and carbon black, and also organic pigments, such as phthalocyanines, quinacridones and perylenes, and also dyes, such as nigrosine and anthraquinones.
Nucleating agents which may be used are sodium phenylphosphinate, alumina, silica and preferably talc.
Other lubricants and mold-release agents which differ from D) and are usually used in amounts of up to 1% by weight are preferably long-chain fatty acids (e.g. stearic acid or behenic acid), salts of these (e.g. calcium stearate or zinc stearate) or montan waxes (mixtures of straight-chain saturated carboxylic acids having chain lengths of from 28 to 32 carbon atoms), and also low-molecular-weight polyethylene waxes and low-molecular-weight polypropylene waxes.
Examples of plasticizers which may be mentioned are dioctyl phthalates, dibenzyl phthalates, butyl benzyl phthalates, hydrocarbon oils and N-(n-butyl)benzenesulfonamide.
The novel molding compositions may also comprise from 0 to 2% by weight of fluorine-containing ethylene polymers. These are polymers of ethylene with a fluorine content of from 55 to 76% by weight, preferably from 70 to 76% by weight.
Examples of these are polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymers and tetrafluoroethylene copolymers with relatively small proportions (generally up to 50% by weight) of copolymerizable ethylenically unsaturated monomers. These are described, for example, by Schildknecht in xe2x80x9cVinyl and Related Polymersxe2x80x9d, Wiley-Verlag, 1952, pp. 484-494 and by Wall in xe2x80x9cFluoropolymersxe2x80x9d (Wiley Interscience, 1972).
These fluorine-containing ethylene polymers have homogeneous distribution in the molding compositions and preferably have a particle size d50 (number-average) in the range from 0.05 to 10 xcexcm, in particular from 0.1 to 5 xcexcm. These small particle sizes may particularly preferably be achieved by using aqueous dispersions of fluorine-containing ethylene polymers and incorporating these into a polyester melt.
The novel thermoplastic molding compositions may be prepared by methods known per se, by mixing the starting components in conventional mixing apparatuses, such as screw extruders, Brabender mixers or Banbury mixers, and then extruding the same. The extrudate may be cooled and comminuted. It is also possible to premix individual components and then to add the remaining starting materials individually and/or likewise in a mixture. The mixing temperatures are generally from 230 to 290xc2x0 C.
In a preferred method, components B) to D), and also, if desired, conventional additives E), can be mixed with a polyester prepolymer, compounded and pelletized. The resultant pellets are then condensed to the desired viscosity in the solid phase under an inert gas, continuously or batchwise, at a temperature below the melting point of component A).
The novel thermoplastic molding compositions have good mechanical and flame-retardant properties and also pass the glow-wire test. During their processing there is very little change in the polymer matrix, flowability is improved and mold deposits are greatly reduced. They are suitable for producing fibers, films and moldings, in particular for applications in the electrical and electronics sectors. Examples of these applications are lamp parts, such as lamp sockets and lamp holders, plugs and multipoint connectors, coil formers, casings for capacitors or connectors, and circuit-breakers, relay housings and reflectors.

Flame-proofed polyester molding materials

Abstract: A) from 5 to 96% by weight of a polyester,

Abstract: B) from 1 to 30% by weight of a phosphinate of formula I and/or of a diphosphinate of formula II and/or polymers of these

Abstract: R1 and R2 are linear or branched C1-C6-alkyl, phenyl or hydrogen,

Abstract: R3 is linear or branched C1-C10-alkylene, arylene, alkylarylene or arylalkylene,

Abstract: M is an alkaline-earth or alkali metal, Zn, Al, Fe or B,

Abstract: m is an integer from 1 to 3,

Abstract: n is an integer from 1 to 3,

Abstract: is 1 or 2 and

Abstract: C) from 1 to 30% by weight of at least one organic phosphorus-containing flame retardant,

Abstract: D) from 0 to 5% by weight of at least one ester or amide of saturated or unsaturated aliphatic carboxylic acids having from 10 to 40 carbon atoms with saturated aliphatic alcohols or amines having from 2 to 40 carbon atoms, and

Abstract: E) from 0 to 60% by weight of other additives, where the total of the percentages by weight of components A) to E) is 100%.


Methods and systems for electrical sensing, measurement and characterization of display elements are described. An embodiment includes integrating the electrical sensing, measurement and characterization with the display drive scheme. This embodiment allows for measurement of DC or operational hysteresis voltages and/or response times of interferometric modulator MEMS devices, for example, to be fully integrated with the display driver IC and/or the display drive scheme. Another embodiment allows these measurements to be performed and used without resulting in display artifacts visible to a human user. Another embodiment allows the measurement circuitry to be integrated with the display driver IC and/or the display drive scheme re-using several existing circuitry components and features, thus allowing for integration of the measurement method and its use relatively easily.

1. Field of the Invention
This invention relates to microelectromechanical systems. More particularly, this invention relates to methods and apparatus for improving the performance of microelectromechanical systems such as interferometric modulators.
2. Description of the Related Art
Microelectromechanical systems (MEMS) include micro mechanical elements, actuators, and electronics. Micromechanical elements may be created using deposition, etching, and/or other micromachining processes that etch away parts of substrates and/or deposited material layers or that add layers to form electrical and electromechanical devices. One type of MEMS device is called an interferometric modulator. As used herein, the term interferometric modulator or interferometric light modulator refers to a device that selectively absorbs and/or reflects light using the principles of optical interference. In certain embodiments, an interferometric modulator may comprise a pair of conductive plates, one or both of which may be transparent and/or reflective in whole or part and capable of relative motion upon application of an appropriate electrical signal. In a particular embodiment, one plate may comprise a stationary layer deposited on a substrate and the other plate may comprise a metallic membrane separated from the stationary layer by an air gap. As described herein in more detail, the position of one plate in relation to another can change the optical interference of light incident on the interferometric modulator. Such devices have a wide range of applications, and it would be beneficial in the art to utilize and/or modify the characteristics of these types of devices so that their features can be exploited in improving existing products and creating new products that have not yet been developed.
The systems, methods, and devices described herein each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope, prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled "Detailed Description of Certain Embodiments" one will understand how the features described herein provide advantages over other display devices.

Method and apparatus for sensing, measurement or characterization of display elements integrated with the display drive scheme, and system and applications using the same


A floor cleaning wipe comprising a water insoluble substrate which is impregnated with a floor cleaning composition.

The present invention relates to a floor cleaning wipe which comprises a water insoluble substrate which has been impregnated with a liquid floor cleaning composition.
The patent literature describes numerous wipes for both body cleaning and cleaning of hard surfaces but none describe the instant cleaning wipes which have improved cleaning characteristics in the minimization of streaking and residue, together with optimum mileage.
U.S. Pat. Nos. 5,756,612; 5,763,332; 5,908,707; 5,914,177; 5,980,922 and 6,168,852 teach cleaning compositions which are inverse emulsions.
U.S. Pat. Nos. 6,183,315 and 6,183,763 teach cleaning compositions containing a proton donating agent and having an acidic pH.
U.S. Pat. Nos. 5,863,663; 5,952,043; 6,063,746 and 6,121,165 teaches cleaning compositions which are water emulsions.
A floor cleaning wipe for cleaning floors comprises a water insoluble substrate consisting of three layers which is impregnated with a liquid cleaning composition containing tall oil soap, a sultaine surfactant, an amine oxide, a perfume, a preservative and water, wherein the liquid cleaning composition is not an emulsion and does not contain a sulfate or sulfonate surfactant, proteins, metallic salts, enzymes, amides, sodium hypochlorite, dimethicone, N-methyl-2-pyrrolidone, monoalkyl phosphate or silicon based sulfosuccinate or a hydrophilic polymer selected from the group consisting of polysaccharides, polycarboxylates, polyvinyl alcohols, polyvinylpyrrolidones, polyethylene glycols, methylvinyl ethers, and mixtures thereof.
The present invention relates to a floor cleaning wipe for hard surfaces which comprises approximately:
(a) 5 wt. % to 20 wt. % of a water insoluble substrate formed from three layers; and
(b) 80 wt. % to 95 wt. % of a liquid floor cleaning composition being impregnated in said water insoluble substrate, wherein said liquid cleaning composition comprises:
(i) 0.05 wt. % to 0.5 wt. %, more preferably 0.075 wt. % to 0.25 wt. % of at least one alkali metal salt of a long chain unsaturated fatty acid having about 8 to about 24 carbon atoms such as a refined tall oil fatty acid;
(ii) 0.001% to 0.01% of a sultaine surfactant;
(iii) 0.001% to 0.01% of an amine oxide surfactant;
(iv) 0 wt. % to 0.7 wt. %, more preferably 0.01 wt. % to 0.05 wt. % of a preservative;
(v) 0.01 to 0.5 wt. % of a perfume;
(vi) 0 to 0.4 wt. %, more preferably 0.01 to 0.2 wt. % of a metal chelant; and
(vii) the balance being water, wherein the composition has a pH of about 9 to about 11, more preferably about 9.4 to about 10.6 and the composition does not contain a hydrophilic polymer selected from the group consisting of polysaccharides, polycarboxylates, polyvinyl alcohols, polyvinylpyrrolidones, polyethylene glycols, methylvinyl ethers, and mixtures thereof.
As used herein and in the appended claims the term xe2x80x9cperfumexe2x80x9d is used in its ordinary sense to refer to and include any non-water soluble fragrant substance or mixture of substances including natural (i.e., obtained by extraction of flower, herb, blossom or plant), artificial (i.e., mixture of natural oils or oil constituents) and synthetically produced substance) odoriferous substances. Typically, perfumes are complex mixtures of blends of various organic compounds such as alcohols, aldehydes, ethers, aromatic compounds and varying amounts of essential oils (e.g., terpenes) such as from 0% to 80%, usually from 10% to 70% by weight, the essential oils themselves being volatile odoriferous compounds and also serving to dissolve the other components of the perfume.
In the present invention the precise composition of the perfume is of no particular consequence to cleaning performance so long as it meets the criteria of having a pleasing odor. Naturally, of course, especially for cleaning compositions intended for use in the home, the perfume, as well as all other ingredients, should be cosmetically acceptable, i.e., non-toxic, hypoallergenic, etc.. The instant compositions show a marked improvement in ecotoxocity as compared to existing commercial products.
The preferred long chain unsaturated fatty acids of the instant invention have about 8 to about 24 carbon atoms, more preferably about 10 to about 20 carbon atoms. A preferred unsaturated fatty acid mixture is a refined tall oil fatty acid. A typical tall oil fatty acid contains mono unsaturated C16-18 fatty acid; a C18 diene unsaturated fatty acid; a C16-18 triene unsaturated fatty acid; and a C16-18 saturated fatty acid. Other unsaturated fatty acids that are usable in the instant compositions are unsaturated vegetable oil fatty acids, including soy, peanut, corn, cottonseed, linseed and refined oleic fatty acids, and fatty acids consisting predominantly of C18 (average) unsaturated fatty acids and mixtures thereof. The unsaturated fatty acid reacts in situ with the alkali metal hydroxide to form the alkali metal salt of the unsaturated fatty acid.
The composition contains about 0.001 wt. % to about 0.01 wt. % of an amine oxide, more preferably about 0.003 wt. % to about 0.08 wt. %. The preferred amine oxide is cocoamido-propyldimethyl amine oxide. The amine oxide is depicted by the formula:
wherein R1 is an alkyl, 2-hydroxyalkyl, 3-hydroxyalkyl, or 3-alkoxy-2-hydroxypropyl radical in which the alkyl and alkoxy, respectively, contain from about 8 to about 18 carbon atoms; R2 and R3 are each methyl, ethyl, propyl, isopropyl, 2-hydroxyethyl, 2-hydroxypropyl, or 3-hydroxypropyl; and n is from 0 to about 10. Particularly preferred are amine oxides of the formula:
wherein R1 is a C12-18 alkyl and R2 and R3 are methyl or ethyl. The above ethylene oxide condensates, amides, and amine oxides are more fully described in U.S. Pat. No. 4,316,824 (Pancheri), incorporated herein by reference. An especially preferred amine oxide is depicted by the formula:
wherein R1 is a saturated or unsaturated alkyl group having about 6 to about 24 carbon atoms, R2 is a methyl group, and R3 is a methyl or ethyl group. The preferred amine oxide is cocoamidopropyl-dimethylamine oxide.
The composition also contains about 0.001 wt. and to about 0.01 wt. %, more preferably about 0.003 wt. % to about 0.08 wt. % of a sultaine which is preferably a cocoamido-propylhydroxy sultaine. The sultaine can be depicted by the formula:
wherein R1 is a saturated or unsaturated alkyl group having about 6 to about 24 carbon atoms, R2 is a methyl or ethyl group, R3 is a methyl or ethyl group, M+ is about 1 to about 6, and n+ is an alkali metal cation. The most preferred hydroxysultaine is a potassium salt of cocoamidopropyl hydroxysultaine.
The combination of the amine oxide and the sultaine functions to serve as a viscosity control agent while functioning as a means for the dispersion of lime soap.
The final essential ingredient in the instant composition is water. The proportion of water in the compositions generally is in the range of 98 wt. % to 99.8 wt. %.
The floor cleaning composition of this invention may, if desired, also contain other components either to provide additional effect or to make the product more attractive to the consumer. The following are mentioned by way of example: Colors or dyes in amounts up to 0.5%. The preservative which is used at a concentration of 0.01 wt. % to 2 wt. % is selected from the group consisting of formaldehyde, iodo propynyl butyl carbamate, 5-bromo-5-nitro-dioxan1,3; 5-chloro-2-methylisothalizolin-3-one and mixtures thereof. Typical methyl chelating agents are ethylene diamine tetraacetate acid-sodium salt, hydroxy ethylene theylene diamine triacetic acid-trisodium salt and ethylene diamine disuccinate pH adjusting agents, such as sulfuric acid or sodium hydroxide, can be used as needed.
The cleaning compositions are prepared by simple batch mixing at 25xc2x0 C.-30xc2x0 C. The water insoluble substrate is impregnated with the liquid cleaning composition by means of a positive impregnation process. The liquid is positively fed into the water insoluble substrate through a controlled gear pump and injection bar at a ratio of about 6 to 9 grams of liquid cleaning composition to about 1 gram of the nonwoven fabric.
The water insoluble substrate can be square, rectangular, oval, circular or any other geometrically shape such that the water insoluble substrate can be readily attached to the head of a mop having a similar geometrical shape. The water insoluble substrate comprises three layers wherein the first and second outer layers are bonded together at least along their peripheral outer edges of the two outer layers and the middle layer which is of a smaller dimension than the two outer layes is contained in the chamber formed by the first and second outer layers, wherein the middle layer can optionally be bonded to either the first or second outer layers or to both of the outer layers. The first outer layer which is the floor scrubbing layer and is an apertured hydrotangled mixture of natural and synthetic fibers. The second outer layer is a backing layer and is a low bonded polypropylene spunbond fabric. The middle layer is a high bulk cellulose (wood pulp) with a latex binder which is designated to hold the liquid composition, wherein the bonding can be any suitable means such as mechanical, ultrasonic or chemical means. The first outer layer comprises about 52 wt. % to 68 wt. % of the water insoluble substrate. The second outer layer comprises about 20 wt. % to 30 wt. % of the water insoluble substrate. The middle layer comprises about 10 wt. % to 20 wt. % of the water insoluble substrate.
Preferred water insoluble substrate is manufactured by the Ahlstrom Corporation and designated as Ahistrom IV nonwoven comprising about 59.7 wt. % the first outer layer; about 25.7 wt. % of the second outer layer and about 14.6 wt. % of the middle layers are joined together by sufficient hot melt means.
The following example illustrates a liquid cleaning composition of the described invention. The exemplified composition is illustrative only and does not limit the scope of the invention. Unless otherwise specified, the proportions in the examples and elsewhere in the specification are by weight.


A pharmaceutical composition for topical administration, including, as the pharmaceutically active component, at least 5% by weight, based on the total weight of the composition of a piperidinopyrimidine derivative or a pharmaceutically acceptable salt thereof; an acid in an amount to completely solubilise the piperidinopyrimidine derivative or a pharmaceutically acceptable salt thereof; a solvent composition including at least two of water, a lower alcohol and a co-solvent selected from one or more of the group consisting of aromatic and polyhydric alcohols; wherein when the co-solvent includes propylene glycol, it is present in an amount of less than approximately 10% by weight.

The present invention relates to a vehicle system for a pharmaceutical composition comprising a piperidinopyrimidine derivative. More particularly minoxidil and to a pharmaceutical composition incorporating the vehicle system. Minoxidil is a pharmaceutically active ingredient having several indications including use as a hair growth stimulant.
Minoxidil has poor solubility in water and ethanol and pharmaceutical preparations currently marketed only contain a small percentage of minoxidil. That is, below 5%.
Numerous formulations comprising minoxidil have been published in the prior art including U.S. Pat. Nos. 4,139,619, 4,820,512, 5,104,646, 5,225,189, 4,938,953, 4,596,812, 5,006,332, 5,156,836 and 5,643,942. Many of the formulations require (or would require where the amount of minoxidil is greater than 5%) a very high percentage (often in the range of 30 to 50%) of propylene glycol or a similar glycol product in order to improve the solubility of minoxidil. Due to the viscosity and tack of propylene glycol, large amounts of propylene glycol or similar agents in a composition are not pharmaceutically or cosmetically elegant and may be unacceptable to the consumer. In addition, high concentrations of propylene glycol may cause local irritation and hypersensitivity upon application to the scalp.
It would accordingly be a significant advance in the art if a composition could be provided which would permit the inclusion of an increased percentage of the active ingredient, but without the disadvantages associated with a high propylene glycol concentration.
Accordingly, it is an object of the present invention to overcome, or at least alleviate, one or more of the difficulties and deficiencies related to the prior art. These and other objects and features of the present invention will be clear from the following disclosure.

This patent is subject to a terminal disclaimer.