A gum product comprises a soft gum core having a plurality of regions of different colors visible on an outer surface of the core, and a crunchy edible coating covering the outer surface of the core, the coating being substantially transparent such that the core regions of different colors are visible through the coating. The regions of different colors can also have different flavors. The coating preferably is formed of sorbitol and is free of any whitening agents that would make the coating opaque.

The invention relates to chewing gum. The invention relates more particularly to a coated chewing gum product that is co-extruded or otherwise manufactured so that it has two or more portions that are of different colors.
Multicolored chewing gum products, in which a given piece of gum has two or more portions of different colors, are known. For example, U.S. Pat. No. 4,352,823, the disclosure of which is incorporated herein by reference, discloses a co-extruded gum that has an extruded center portion surrounded by and bonded to an extruded outer shell portion. Additionally, U.S. Pat. Nos. 5,626,892, 5,437,879, 4,835,000, and 4,834,986, the disclosures of which are incorporated herein by reference, disclose various multicolored gum products, some of which are also multiflavored, the different colors corresponding to different flavors.
It is also known to coat a gum product with a hard shell or crunchy coating. For example, U.S. Pat. No. 4,753,790, the disclosure of which is incorporated herein by reference, discloses a chewing gum having a hard shell formed from sorbitol. Additionally, U.S. Pat. Nos. 5,603,970 and 5,376,389, the disclosures of which are incorporated herein by reference, disclose gum products having hard coatings of erythritol, xylitol, and other polyols. Such coatings are typically applied to ball-type or pellet-type gum products, and generally have a solid opaque color provided by various additional ingredients in the coating composition, such as film forming agents, binding agents, whiteners, food colors, and similar ingredients.
The present invention provides a unique gum product comprising a soft gum core having a plurality of regions of different colors visible on an outer surface of the core, and a crunchy edible coating covering the outer surface of the core, the coating being substantially transparent such that the core regions of different colors are visible through the coating. The regions of different colors can also have different flavors.
The coating preferably comprises sorbitol as a primary ingredient, and can have various additional ingredients such as film-forming agents, binding agents, flavorings, sweeteners, and others. Notably, the coating does not include any dispersing or whitening agent such as titanium dioxide, which is commonly used in hard coatings for chewing gum, or any other ingredient that would make the coating opaque or otherwise impair the transparency of the coating. The gum product can be formed in any desired configuration including but not limited to stick, pellet, or ball form.
The present invention now will be described more fully hereinafter with reference to certain preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The gum product of the present invention has a relatively soft gum core and a hard, crunchy outer shell or coating that covers the core. The gum core has two or more regions of different colors, and the different colors can also have different flavors if desired. The gum core is preferably prepared by mixing two or more separate batches of gum mixture having different colors, and feeding the various gum mixtures to an extruder that coextrudes the gum mixtures to form a coextrudate. The coextrudate can be formed as a center portion surrounded by an outer portion of different color, as a laminated structure (e.g., two layers of different colors in face-wise disposition to each other), as a veined structure, as a swirled structure, or in any other desired configuration.
Each gum mixture includes a water-soluble bulk portion, a generally water-insoluble chewing gum base, and one or more flavoring and coloring agents. The water-soluble portion dissipates over a period of time during chewing, while the gum base portion remains in the mouth throughout the chewing process.
The insoluble gum base generally includes elastomers, resins, fats, oils, waxes, plasticizers, and inorganic fillers.
The elastomers may include polyisobutylene, isobutylene-isoprene copolymer, styrene butadiene rubber, natural latexes such as hevea brasiliensis, chicle, and jelutong, or the like.
The resins may include synthetic resin such as polyvinyl acetate with a molecular weight from about 5,000 to 100,000, natural resins such as glycerol ester of gum, wood, or tall oil rosin, partially or fully hydrogenated glycerol ester of gum, wood, or tall oil rosin, glycerol ester of polymerized gum, wood, or tall oil rosin, pentaerythritol ester of gum, wood, or tall oil rosin, methyl ester of partially hydrogenated gum, wood, or tall oil rosin, and terpene resins derived from delta limonene or xcex1 and xcex2 pinene, or mixtures thereof.
The fats and oils may include animal fats such as lard and tallow, or vegetable oils such as soybean, cottonseed oil, palm oil, coconut oil, or other fully or partially hydrogenated vegetable oils, and cocoa butter.
The waxes may also include petroleum waxes such as paraffin and microcrystalline wax, or natural waxes such as beeswax, candelilla wax, carnauba wax and polyethylene wax.
The gum base may also include filler such as calcium carbonate, magnesium carbonate, talc, dicalcium phosphate, or the like.
The gum base may also include plasticizers such as glycerol monostearate, glycerol triacetate, glycerin, lecithins, or the like.
The gum base may also include other ingredients such as antioxidants, colors, and emulsifiers or the like.
The present invention can employ any commercially acceptable chewing or bubble gum base. The gum base generally constitutes from about 5 to about 95% by weight of the gum core, and more typically about 20 to 75% of the gum core.
The water-soluble portion of the chewing gum core, which generally makes up from about 5 to about 95% by weight of the gum core, and more typically about 25 to 80% of the gum core, may include softeners, bulk sweeteners, high intensity sweeteners, flavoring agents, colors and combinations thereof.
Softeners in the gum, also known as plasticizers or plasticizing agents, such as glycerin, can be added to the chewing gum center in order to make the gum softer and more easily chewable.
Aqueous bulk sweetener solutions such as those containing sorbitol, xylitol, lactitol, maltitol, hydrogenated isomaltulose and other polyols, or combinations thereof, may also be used as softeners and binding agents in the chewing gum center.
Powder bulk sweeteners that can be used in the gum core may include sweeteners like sugar alcohols such as sorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, lactitol, maltitol, hydrogenated isomaltulose, or the like, alone or in combination.
Bulk sweeteners generally make up about 5 to about 90% by weight of the gum core, and more typically about 10 to 80% of the gum core.
High intensity sweeteners may also be used and are commonly used with sugarless bulk sweeteners. These may include but are not limited to sucralose, aspartame, salts of acesulfame, alitame, saccharin and its salts, cyclamic acid and its salts, glycyrrhizin, dihydrochalcones, thaumatin, monellin, and the like, alone or in combination.
High intensity sweeteners generally make up about 0.001 to about 5% by weight of the gum core, and more typically about 0.05 to about 2.0% of the gum core.
The sweetener may also function in the chewing gum in whole or in part as a water-soluble bulking agent.
The softener may also provide additional sweetness.
Flavoring agents that can be used in the gum core include essential oils and artificial flavors, or mixtures thereof, including natural oils derived from plants and fruits such as citrus oils, peppermint oil, spearmint oil, other mint oils, clove oil, oil of wintergreen, anise, and the like.
Artificial flavorings can comprise fruit flavors such as strawberry, cherry, banana, melon, or the like.
Essential oil and artificial flavoring agents may be combined in the gum core.
The flavoring agents generally make up about 0.05 to about 10% by weight of the gum core, and more typically about 0.1 to 5% of the gum core. The flavoring can be added both as liquid flavoring or in a mixture of liquid flavoring combined with spray-dried flavor or encapsulated flavoring.
In accordance with preferred embodiments of the invention, the gum core is formulated as shown in the following table:
Each gum mixture used in the gum core is generally manufactured by sequentially adding the various chewing gum ingredients to any commercially available mixer known in the art to produce a batch of a gum mixture.
The batch size typically will be from about 20 kg to about 2000 kg. Generally, production of the batch starts with first melting the gum base and adding it to the running mixer. To insure homogenous mixture the other ingredients are added successively to the melted gum base. The cold gum base alternatively may be plasticized in the running mixer before adding other ingredients. Color and emulsifiers can be added at the beginning of the mixing procedure.
A softener such as liquid sorbitol or glycerin can be added next along with isomaltulose syrup and part of the powder bulk portion. Further parts of the liquid and powder bulk portion may then be added to the mixer.
The flavoring agents are typically added with the final part of the bulk portion. The entire mixing process typically takes from 5 to 25 minutes, although longer mixing times are sometimes required. Those skilled in the art will recognize that variations in this mixing procedure, or other mixing procedures, may be followed.
To produce the multi-colored gum in accordance with the present invention, two or more separate batches of gum are prepared in separate mixers as indicated above, each having a different color, and optionally a different flavor if desired.
After the ingredients have been thoroughly mixed, the gum mixtures are discharged from their respective mixers and are fed to a co-extruder or other suitable device that shapes the gum product into the desired form such as chunks or pellets for making dragees.
Alternative processes can be used, such as co-extruding a continuous sheet that is subsequently rolled, scored, and divided into pieces such as pellets or any other shape that can be coated, or any other suitable process for making the desired form. The product is shaped in such a way that at least two colors are visible on an outer surface of the product. Optionally, the product can also have two portions of two different flavors.
There can be a maturing time included after the discharge of the gum and feeding into the extruder, but this will depend on the gum and the available technology for forming the product.
Co-extrusion devices and processes, and devices for rolling and scoring, are well known in the art and hence are not further described herein.
After the chewing gum core has been manufactured, shaped, and optionally matured, the hard coating can be applied. Hard coatings of sorbitol are preferred in the present invention.
Such coatings are known, but prior sorbitol coatings have generally included ingredients that make the coatings opaque and colored. A typical sorbitol coating composition, for example, is formed by preparing a saturated liquid sorbitol syrup that contains from about 60 to 78 weight percent of sorbitol powder (the weight percent required to reach the saturation point being dependent on the syrup temperature) dissolved in a solvent such as water, and adding various other ingredients as desired. The sorbitol/water mixture can be a commercially available liquid sorbitol comprising sorbitol solids dissolved in water, which is typically sold as a 70% concentration liquid sorbitol (i.e., a solution comprising 70% sorbitol solids by weight and the remainder water). The coating syrup generally also includes some type of dispersing agent for the purpose of whitening and tack reduction. Commonly used dispersing agents include titanium dioxide and talc.
However, in accordance with the present invention, the hard sorbitol coating must be transparent so that the multicolored appearance of the gum core can be seen through the coating. Accordingly, the coating composition used for making the hard coating is free of any ingredients that would make the resulting coating opaque, and preferably is also free of any colorants. Thus, titanium dioxide or similar dispersing agents are not used.
The sorbitol coating composition can include other ingredients such as thickeners, flavoring agents, artificial sweeteners, film formers, and binding agents. Flavoring agents contemplated by the present invention include essential oils and artificial flavors, or mixtures thereof, including but not limited to oils derived from plants and fruits such as citrus oils, fruit essences, peppermint oil, spearmint oil, other mint oils, clove oil, oil of wintergreen, anise and fruit flavoring or the like.
Artificial sweeteners contemplated for use in the coating may include but are not limited to synthetic substances such as saccharin, thaumatin, alitame, saccharin salts, aspartame, sucralose, and acesulfame-K.
Film-forming agents that can be added to the coating syrup include but are not limited to methyl cellulose, gelatins, hydroxypropyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and the like, or combinations thereof.
Binding agents may be added either as an initial coating on the chewing gum core or may be added directly into the syrup. Binding agents contemplated by the present invention include alginate, cellulosics, vegetable gums, or the like.
The coating syrup preferably includes a thickener such as gum arabic, gelatin, carrageenan, or the like. Preferred types of gum arabic are the instantly soluble types, but slow dissolving types alternatively can be used.
Suitable ranges of ingredient weight percentages of a gum product (based on weight of the finished gum piece comprising the gum core and the coating) in accordance with preferred embodiments of the invention are given in the following Table II:
The proportions between the gum core and the coating generally will range between 10:1 and 1:10. The weight of a gum piece will generally be between about 0.5 gram and 10 grams.
The ingredients of the coating syrup preferably are heated and mixed thoroughly to a uniform temperature. It is important that the thickener be fully dissolved in the syrup.
The coating syrup is then stored at a temperature of about 10xc2x0 C. to about 90xc2x0 C. Once the sorbitol syrup has been prepared, the syrup may be mixed with, sprayed upon, poured over, or added to the gum cores in any way known to those skilled in the art.
For example, the hard coating process can be carried out in a rotating pan. Gum cores to be coated are placed into the rotating pan to form a moving mass. The syrup is applied or distributed over the gum cores. Once the coating has dried to form a hard surface, additional syrup additions can be made to produce a plurality of coatings or multiple layers of hard coating.
Any suitable coating equipment may be used when practicing the invention. Examples of such equipment include traditional coating pans as well as newer, high technology systems such as those produced by Driam of Germany, Dumoulin of France, and Latini.
In the hard coating panning procedure, the coating syrup is generally added to the gum cores at a temperature of from about 10xc2x0 C. to about 90xc2x0 C., and more preferably from about 30xc2x0 C. to about 70xc2x0 C. The coating on the gum cores may be applied in a single hard layer or in a plurality of hard layers.
In general, applying a plurality of layers involves applying a single coat, allowing the coat to dry, and then repeating the process obtains a plurality of layers. Any number of coats may be applied to the gum cores. Preferably, the gum cores are coated with about 30 to 70 layers.
Once a portion of syrup is applied to the gum cores, the wet syrup coating is dispersing on the cores and dried; such drying is done by forced-air drying in a temperature range of from about 15xc2x0 C. to about 45xc2x0 C. The drying air should have relative humidity below 50% RH. Each application of a wet syrup coating to the gum pieces is followed by a distribution period without air and then a forced-air drying of the coating, and the coating and drying steps are alternated until the desired numbers of coating layers have been deposited on the gum pieces.
A sealing coating of food-grade wax (e.g., carnauba wax or the like) may be applied over the hard coating, if desired, in order to seal the crunchy coating to reduce the exposure of the coating to atmospheric moisture.

Multicolored chewing gum with crunchy transparent coating


A method for treating an underground reservoir, which method comprises introducing into the reservoir a treatment fluid comprising, dissolved or dispersed in water, an ester and a non-enzyme catalyst capable of increasing the rate of hydrolysis of the ester, such that the ester hydrolyses to produce an organic acid to dissolve acid soluble material present within the reservoir.

The method of the present invention is generally applicable to the production of oil, gas or water from wells drilled into underground reservoirs.
During drilling, workover and production operations there are numerous situations where the production rate of an oil, gas or water well following these operations is limited due to the presence of formation damage. Types of damage include, but are not limited to, the presence of polymer-containing filter cakes including drilling mud filter cakes, fluids (including hydraulic fracturing fluids) filtrates or residues including polysaccharide-containing filter cakes, fluids, filtrates or residues, particulate materials such as fluid loss control agents and rock fines, biofilms, scales and asphaltenes. Damage may arise as a result of drilling, production, injection workover or other oilfield operations.
Damage can be near wellbore, for example the presence of drilling mud or fracturing fluid filter cake, or damage may be present deeper into the formation, for example mineral scale deposited in natural or induced fractures or in the rock matrix.
The effective removal of damage, especially near wellbore damage such as filter cake, can significantly increase the production rate of hydrocarbon or water producing wells penetrating underground formations. The effective removal of damage can also increase the injectivity of injection wells,
Conventional acids have been used for many years to treat damage in underground formations and stimulate the rate of oil or gas production. However, conventional acids have several drawbacks. They react rapidly with acid soluble materials which can prevent effective placement of reactive acid deep into carbonate formations or throughout long horizontal wellbores resulting in poor zonal coverage. These acids are also hazardous in use. To improve zonal coverage the use of high pressure, high rate injection is often attempted, which increases the hazards associated with their use of conventional acids. Due to the high corrosivity of conventional acids the use of corrosion inhibitors is also generally required. There is a greater need for corrosion inhibitors in higher temperature formations and corrosion inhibitors are generally toxic.
If acids can be delivered sufficiently well into the formation, acidising may also be effective in stimulating undamaged formations by increasing the permeability of the rock matrix around the wellbore. For example, increasing the permeability of a zone of 3 to 5 m radius around a vertical wellbore by 3-4 fold is expected to increase the rate of fluids production (or injection rate) by about 20% in a situation where there is no near wellbore damage. The efficient delivery of acids into fractures such as induced fractures or natural fractures can also increase the conductivity of the fractures allowing higher rates of fluid production or injection.
Acids may also be used to break acid sensitive gels such as cross linked guar-borate gels used in hydraulic fracturing and other oilfield applications. Efficient breaking of gels is generally required to obtain maximum production after such treatments.
One approach which can improve zonal coverage has been the use of solutions of carboxylic acid esters which hydrolyse at high temperatures to produce a carboxylic acid (U.S. Pat. No. 3,630,285). Preferably, the formation temperature for this process is greater than about 150xc2x0 C. Because the acid is produced predominantly after placement of the fluid excellent zonal coverage can be achieved. The preferred esters used in U.S. Pat. No. 3,630,285 were ethyl acetate and methyl formate. These compounds have the disadvantage of low flash points and have other health and safety drawbacks such as some degree of toxicity.
It is an object of the present invention to provide simple and effective methods for increasing the rate of hydrolysis of esters to allow ester based acidising of underground formations to be carried out within a reasonable time scale. It is a further object of the present invention to provide simple and effective methods for acidising underground formations in combination with one or more polymer breakers.
It is also an object of the present invention to provide a method by which increased rates of ester hydrolysis can be obtained in heavy brines.
The present invention further provides a method by which controlled acidising, with or without suitable polymer breakers, may be used for the treatment of filter cakes following gravel packing operations, by incorporation of suitable components into the gravel packing fluid.
Accordingly, the present invention provides a method for treating an underground reservoir, which method comprises introducing into the reservoir a treatment fluid comprising, dissolved or dispersed in water, an ester and a non-enzyme catalyst capable of increasing the rate of hydrolysis of the ester, such that the ester hydrolyses to produce an organic acid to dissolve acid soluble material present within the reservoir.
The reservoir may be a hydrocarbon reservoir, for instance a gas or oil reservoir. Alternatively the reservoir may be a water reservoir. When it is a hydrocarbon reservoir the method of the invention may further include recovering a hydrocarbon from the treated reservoir. Likewise, when it is a water reservoir the method of the invention may further include recovering water from the treated reservoir. Typically the reservoir is, or includes, a carbonate rock structure.
Preferred esters for incorporation into treatment fluids to be used in the present invention are carboxylic acid esters, preferably those with low toxicity, high flash point and high environmental acceptability. Esters of ethanoic and methanoic acid (acetic and formic acid) are particularly suitable. The calcium and magnesium salts of these acids have good solubility in water.
The ester should be at least slightly water soluble. Preferably the ester should be soluble to at least 1% w/v in water and most preferably soluble to at least 5% in water. The solubility of some esters may be less in high salt concentration fluids, such as a heavy brine. In such cases an ester which is completely soluble in the base fluid at the desired concentration will normally be selected.
The acid generated in situ according to the method of the present invention is an organic acid, generally an aliphatic carboxylic acid. Preferably the acid is of formula RCO2H wherein R is hydrogen, an alkyl group having from 1 to 6 carbon atoms orxe2x80x94Rxe2x80x2xe2x80x94CO2H where Rxe2x80x2 is a bond or an alkylene group having from 1 to 6 carbon atoms, the said alkyl or alkylene group being unsubstituted or substituted by halogen or hydroxy. Where the acid has a hydroxy substituent the ester may, for instance, be a cyclic ester such as a lactone.
The alcohol portion of the ester may be monohydric or polyhydric as long as the esters are sufficiently water soluble at formation temperatures. Partial esters of the polyhydric alcohols can be used in which case the unesterified hydroxyl groups serve to increase the water solubility of the ester.
Suitable examples of the ester include 1,2,3-propanetriol triacetate, 1,2,3-propanetriol diacetate, ethylene glycol diacetate, diethylene glycol diacetate and triethylene glycol diacetate. Most preferably the esters are acetic esters of 1,2,3-propanetriol (glycerol) and 1,2-ethanediol (ethylene glycol). The ester and also the alcohol which is produced when the ester hydrolyses can both act as mutual solvents. The presence of a mutual solvent is generally considered to be beneficial in treatments of hydrocarbon bearing formations, particularly when treating with water based treatment fluids.
The concentration of ester incorporated into the formulations of the present invention will typically be at least 1% w/v but may be up to 20% w/v or higher. In general it has been found that 5% to 10% w/v ester when used in combination with a suitable polymer breaker or breakers is sufficient to give good removal of damage caused by filter cake. Preferably 5% to 20% ester will be used.
The catalyst is any non-enzyme catalyst capable of increasing the rate of hydrolysis of the ester. Catalysis is most simply achieved with (i) a suitable metal ion or ions, particularly transition metal ions, for instance used as simple solutions of metal salts (ii) a suitable organic molecule or molecules or (iii) suitable complexes of a metal ion or metal ions with an organic molecule or organic molecules. Accordingly, in one aspect of the invention the catalyst is, or comprises, a metal ion such as a transition metal ion. In another aspect of the invention the catalyst is, or comprises, an organic molecule. Typically the catalyst is formed from a combination of a metal ion, for instance a transition metal ion, and an organic molecule.
Suitable metal ions include any metal ion which can increase the rate of hydrolysis of a suitable ester either alone or in combination with a suitable organic molecule or molecules. Preferred metals are transition metals, in particular zinc, copper, nickel, cobalt, iron, manganese, chromium, vanadium, titanium, scandium or molybdenum Most preferred are sufficiently water soluble salts or complexes of copper, zinc, iron, manganese, nickel and molybdenum.
Suitable organic molecules include any organic molecule which can increase the rate of hydrolysis of a suitable ester either alone or in combination with a suitable metal ion or ions. Preferred organic molecules are amino acids, peptides, monosaccharides, oligosaccharides, nucleic acids and peptide nucleic acids, or modified or cyclic amino acids, peptides, monosaccharides, oligosaccharides, nucleic acids and peptide nucleic acids, or other small organic molecules.
The organic molecules may be chemically modified, for example by derivatisation, to alter their solubility, binding properties (with respect to the metal ions, esters or products of ester hydrolysis) or, where a complex is the active catalyst, to alter other characteristics of the complexes.
Where the organic molecule is used in combination with a metal ion, an ability of the organic molecule to form a coordination complex with a metal ion is generally desirable. Suitable complexes of a metal ion or metal ions with an organic molecule or organic molecules include any complex which can increase the rate of hydrolysis of a suitable ester.
Catalysts which are particularly valuable are those catalysts where the products of ester hydrolysis are not strongly bound to the catalyst allowing the continuing hydrolysis of further ester molecules.
More than one metal ion and/or organic molecule may be used at the same time. Combinations of metal ions and/or organic molecules which are effective for ester hydrolysis can be selected by a person of skill in the art. In general catalysts will be selected on the basis of their effectiveness at hydrolysing the preferred esters under the required conditions, their cost and their environmental and operational acceptability.
The catalyst will normally be incorporated into the treatment fluid at a concentration sufficient to increase the rate of ester hydrolysis by a factor of at least two fold and preferably 5 to 10 fold above the uncatalysed rate of hydrolysis of the ester. Concentrations of catalyst of 1 to 10 mM with respect to the metal or organic molecule content of the catalyst are generally sufficient, although higher or lower concentrations may be used.
The treatment fluid needs to be retained in the underground reservoir for a period long enough for the desired amount of acid to be produced. Ester hydrolysis in the absence of catalysis proceeds slowly, especially at low temperatures. For example at 10-40xc2x0 C. the hydrolysis may take several weeks. This may be acceptable for some applications such as filter cake removal from a well which has been drilled but which is shut in for an extended time (of at least several weeks) before being put on production. However, generally shorter treatment periods are sought. The treatment fluids used in the method of the present invention will normally require shut in periods of a maximum of 7 days but normally less than 3 days.
In addition to the preferred esters which would normally comprise the majority of the esters present in the treatment fluids used in the current invention, it may also be beneficial in some damage removal applications to include in the formulation esters of chelating compounds such as malonic acid, oxalic acid or succinic acid (U.S. Pat. No. 5,082,056) ethylenediaminetetraacetic acid (EDTA) nitrilotriacetic (NTA) citric acid or hydroxyacetic acid (U.S. Pat. No. 5,223,159) which hydrolyse to produce efficient chelating compounds. Such compounds may be particularly useful to assist in the breaking of cross-linked polymers in combination with other polymer breakers. Some of the acids produced from the hydrolysis of the ester may be able to dissolve certain types of oilfield scale. For example hydroxyacetic acid can dissolve calcium sulphate.
Although it is essential to the method of the present invention to use a non-enzyme catalyst to hydrolyse the ester, there may be circumstances in which such a catalyst is used in combination with an enzyme capable of hydrolysing an ester.
In one embodiment of the invention the treatment fluid further includes a polymer breaker to degrade polymers. Preferred polymer breakers for use in the method of the present invention are oxidants (oxidative breakers), enzyme breakers and catalysts.
Oxidative breakers used in the present invention may be any one of those oxidative breakers known in the art to be useful to react with polysaccharides to reduce the viscosity of polysaccharide thickened compositions or to disrupt filter cakes.
The oxidative breaker is typically introduced in a treatment fluid containing the ester component. The oxidative breaker may be present in solution or as a dispersion. Suitable compounds include persulphates, peroxides, perborates, percarbonates, perphosphates, hypochlorites, persilicates, metal cations and hydrogen peroxide adducts such as urea hydrogen peroxide and magnesium peroxide.
Preferred oxidative breakers for incorporation into treatment fluids to be used in the present invention are peroxides which can decompose to generate hydrogen peroxide. Of the oxidative breakers most preferred are percarbonates and perborates, most especially sodium percarbonate and sodium perborate.
A preferred polymer breaking enzyme used in the present invention includes a hydrolase, such as any one of those polysaccharide degrading enzymes known in the art to be useful to hydrolyse polysaccharides and to reduce the viscosity of polysaccharide thickened compositions or to disrupt filter cakes. The polymer breaking enzymes will be selected on the basis of their known ability to hydrolyse the polysaccharide components known or believed to be contributing to the damage. Examples of suitable enzymes which may be used to break polymers include enzymes which can hydrolyse starch, xanthan, cellulose, guar, scleroglucan, succinoglycan or derivatives of these polymers. If suitable enzyme activities are available, enzymes could also be used to hydrolyse any other polymers suitable for use in drilling, workover or production operations. There is an extensive patent literature relating to polysaccharide degradation by enzymes in oilfield applications (for background and details of specific enzymes see U.S. Pat. Nos. 5,165,477, 5,226,479, 5,247,995, 5,437,331, 5,441,109, 5,562,160, 5,604,186, 5,224,544, 5,476,775, 5,566,759, 4,682,654, 5,067,566, 5,201,370, 5,421,412, 5,547,026, 5,551,515, 4,410,625, 4,690,891 4,886,746, 4,996,153 and 5,032,297)
Any catalyst used in the method of the present invention which is capable of hydrolysing an ester may also be used as a polymer breaker, in which case it needs to exhibit hydrolytic ability against the chemical bonds in a polymer. Thus, in one aspect of the invention the polymer breaker is a non-enzyme catalyst capable of increasing the rate of hydrolysis of the polymer. Suitable catalysts will be selected on the basis of their effectiveness at hydrolysing the preferred polymers under the required conditions, their cost and their environmental and operational acceptability.
Oxidative or enzyme breakers or catalysts may also be used to hydrolyse other, non-polysaccharide polymers which may be incorporated into fluids for drilling workover or production operations.
Where a breaker is incorporated into the treatment fluid, sufficient polymer breaker or gel breaker is normally included to have a substantive effect on the polymer component. The concentration of polymer breaker incorporated into the formulation will vary according to the type of breaker employed, the nature of the polymer and its concentration in the base fluid but will be of the order of 0.005 to 60 kg/m3, preferably 0.2 to 10 kg/m3.
In general it is desirable to use a concentration of breaker which results in the breaking of the polymer over a period of several hours to allow the effective placement of the treatment fluid. For example, too rapid a degradation of a filter cake or biofilm may lead to early localised fluid leak off, adversely affecting placement of the remaining treatment fluid. This is analogous to the situation experienced in treatments using conventional acids, where the fast reaction rate can result in rapid breakthrough and wormholing and uneven fluid leak off. This can prevent the even placement of fluid over long horizontal intervals or into fractures or the rock matrix. It is a feature of the treatment fluids used in the present invention that use of an ester rather than a reactive acid avoids wormholing and improves the placement of the fluid. In order to maintain this advantage in certain applications such as the treatment of long horizontal intervals, too rapid a degradation of polymers in for example filter cakes or biofilms should in general be avoided. Ideally, breakthrough of filter cakes or biofilms will be achieved after a period longer than that amount of time needed to place the treatment fluid throughout the zone requiring treatment. A delay in producing a substantive amount of acid and in breaking polymer allows even treatment of the target zone and excellent zonal coverage.
Use of an ester gives the advantages described in U.S. Pat. Nos. 3,630,285 and 5,678,632 with respect to effective placement of the fluid and avoidance of the use of corrosion inhibitors. Where suitable esters are selected, in particular where low toxicity, high flash point esters are used, there are also health and safety and environmental advantages. The initially neutral or slightly acidic pH of the fluid permits the incorporation of gel breakers such as enzymes and oxidative breakers into the fluid without the compatibility problems encountered when such breakers are incorporated into highly acidic formulations based on mineral or organic acids.
It is preferable to use breakers which are activated by, or whose activity is enhanced by, the change in conditions as the ester hydrolyses to produce acid. For example, peroxides which are activated by the development of acidic conditions or enzymes which have their activity enhanced by the development of acidic conditions. An example of the former is the decomposition of calcium peroxide. This decomposes under acidic conditions to generate hydrogen peroxide.
Enzymes useful as polysaccharide breakers generally have a pH optimum in the range pH 3 to pH 7. Such enzymes will therefore have their activity enhanced by the generation of the moderately acidic conditions arising from hydrolysis of an ester. The generation of acidic conditions by the hydrolysis of esters in the presence of acid soluble material such as calcium or magnesium carbonates results in the formation of a self-regenerating buffer. For example, the production of acetic acid will produce an acetic acid-acetate buffer or production of formic acid a formic acid-formate buffer. If the produced acid reacts with acid soluble material it is replenished by more acid produced from the hydrolysis of remaining ester precursor ensuring maintenance of the buffer. This can provide ideal conditions for polysaccharide degrading enzymes causing less of the enzyme or enzymes to be needed to give the same degree of polymer breaking compared to the same enzymes working under sub-optimal pH conditions. The continual production of acid and maintenance of a buffer system in the method of the present invention even when the produced acid reacts with acid soluble material, ensures favourable pH conditions for enzyme breaker activity are maintained over a prolonged period. This contrasts with standard buffer fluids which contain a low concentration of acid or formulations which produce low concentrations of acid from precursors. In both these cases the acid will react with acid soluble material and will not be replenished. Any enzyme breakers present in this fluid will only operate at a favourable pH for a short period of time before the acid is spent and the pH becomes more alkaline.
In some embodiments of the present invention the effectiveness of the incorporated oxidant breakers can be enhanced by producing more reactive oxidants. Specifically, under certain conditions the production of hydrogen peroxide in the presence of organic acid can result in the formation of a peracid which is a more effective oxidant than the hydrogen peroxide. Thus, in one embodiment of the method of the invention the treatment fluid further comprises a peroxide to generate a peracid polymer breaker in situ.
The ester and other chemicals required for the process of the present invention will normally be technical grade to reduce the cost of the process.
Where an enzyme is used to hydrolyse an ester or as a polymer breaker, it is necessary to select an enzyme which remains active in the treatment fluid under reservoir conditions for at least as long as the catalytic activity is needed. It is generally advantageous for the enzymes to be readily water soluble although the enzymes may also be active and be used in low water activity environments or two-phase systems such as emulsions or dispersions.
Typically, isolated enzymes are used. Enzymes may be isolated from plant, animal, bacterial or fungal sources. The enzymes may be produced from wild-type, conventionally bred, mutated or genetically engineered organisms. The enzymes may, optionally, be chemically modified, as long as they retain or possess the desired catalytic ability. Preferably, the enzymes will be industrial enzymes available in bulk from commercial sources.
A treatment fluid is chosen to reflect the requirements of the treatment, such as amount of acid required, rate of production of acid required, type of breaker needed, and the conditions of the reservoir, in particular the ionic strength and temperature.
The chosen treatment fluid is normally prepared in suitable water for example city (drinking) water, produced water or sea water although in some situations it may be desirable to inject undiluted ester or a blend of ester with a hydrocarbon such as diesel. containing the other components. Typically an ester solution is prepared batchwise in tanks or other suitable vessels by adding the ester to the water with agitation and achieving thorough mixing by recirculating the ester solution through a blender such as a paddle blender for a suitable period of time. In some circumstances, use of an emulsion of the ester may be desirable. The other components (catalyst or catalysts and breaker or breakers) are then added and recirculation continued. If batch wise preparation is not possible or desirable (for example if a dispersion is used which is difficult to keep evenly dispersed in a large holding vessel) or if it is preferred the treatment fluid may be prepared by adding individual components to the water on a continuous, preferably carefully controlled and monitored basis (xe2x80x9con the flyxe2x80x9d) as the treatment fluid is injected into the underground reservoir. Other methods of preparing the chosen treatment fluid will be well known to those skilled in the art.
The concentrations of ester, catalyst and optional additional components such as breakers in the treatment fluid will be selected according to the requirements of the treatment. Concentrations will typically be of the order of 10 to 200 grams of ester per litre of base fluid, 1 to 10 mM catalyst (with respect to the metal ion or organic molecule concentration) and 0.2 to 10 grams per litre of other components , although higher or lower concentrations may be appropriate in some situations. The concentration of any enzyme breaker will be selected such that the polymer/gel will be degraded within the desired period of time. Where enzymes are used, typical enzyme concentrations will be 0.05% to 5% v/v of commercial liquid enzyme preparations or about 0.005 to 0.5% v/v of dried enzyme preparation. Preferably liquid preparations of enzymes will be used for ease of handling.
More than one ester may be incorporated into the treatment fluid depending on the nature of the damage and the type of treatment. Similarly more than one type of catalyst and polymer breaker may be incorporated into the treatment fluid. Where an enzyme preparation is included in the treatment fluid more than one enzyme preparation may be incorporated. A single solution containing all of the components will preferably be used. In one embodiment the treatment fluid further includes an esterase, lipase or protease enzyme. These serve to increase the rate of hydrolysis of the ester.
In some embodiments of the present invention, it may be desirable to incorporate more than one type of breaker, for example an oxidant might be used in combination with an enzyme breaker in the case where two polysaccharides are present but only one is amenable to attack by an enzyme breaker.
Oxidants, enzymes and catalysts may, if desired, also be used in the form of delayed release preparations, such as will be well known by those skilled in the art.
The treatment fluid comprising ester, catalyst and optional polymer breakers is conveniently introduced into the underground formation via injection or production wells. If being introduced into a newly drilled well, particularly if being used to remove damage caused during drilling, such as filter cakes, the treatment fluid may conveniently be introduced via the drill string. This is achieved using the mud pumps. The low corrosivity of the fluid will permit introduction of the fluid into wells or the drill string without the need to add corrosion inhibitors. The fluid will normally be introduced at below fracture pressure but may if desired be injected at above fracture pressure.
The treatment fluid may contain further chemical additives such as are commonly used in the oil industry, such as surfactants, foaming and chelating agents if their inclusion is deemed to be beneficial and if they are compatible with the other components of the treatment fluid.
The treatment fluid may be introduced into the reservoir via a wellbore which extends into the reservoir. The wellbore may be vertical, deviated, inclined or horizontal. For near wellbore treatments, the volume of treatment fluid introduced into the reservoir will typically be at least equal to the wellbore volume plus an allowance for some leak off into the formation. A fluid volume of between 120% and 200% of the wellbore volume will normally be used although if a high rate of fluid loss is expected a volume up to 300% or higher of the well bore volume may be selected. For treatments where the target is damage deeper into the formation such as damage within natural or induced fractures or damage within fracture networks a volume of treatment fluid will be selected appropriate to the requirements of the treatment.
In one embodiment of the present invention, a volume of the treatment fluid, containing both ester and catalyst, which is sufficient to allow the fluid to penetrate one to several metres into a formation around a wellbore or behind a fracture face may be used. The production of acid in-situ can result in an increase in the matrix permeability of a carbonate formation to a depth of one to several metres. Where damage is also removed from the near wellbore region or the fracture faces this will result in a negative skin which will increase the productivity of the well beyond that which can be achieved with even complete near wellbore damage removal. The volume of fluid needed for such treatments will depend on the porosity of the formation, desired depth of penetration and dimensions of the wellbore, fracture or fracture network. Such an approach may also be effective for treating carbonate scaled sandstone reservoirs which also suffer from near wellbore damage, again using a single stage treatment.
In another embodiment of the present invention the ester, catalyst and optional polymer breakers are used to remove filter cake in gravel packing operations. In such operations it is generally acknowledged that it is important to retain a filter cake during placement of the gravel pack. The effective removal of the filter cake after placement of the gravel pack is required in order to ensure high productivity from the gravel packed well. The ester, catalyst and optional polymer breakers may be incorporated into the base fluid used to place gravel for gravel packing operations or placed in the gravel packed well following the treatment. In-situ production of acid within the gravel pack fluid using catalysts ensures that acid is delivered evenly to all parts of the gravel pack adjacent to the filter cake resulting in an even clean up of filter cake.
The well will normally be shut in after introduction of the treatment fluid for a period, typically between 2 hours and a week, preferably 6-48 hours, to allow production of acid and breaking of the polymer. The well is then put on or returned to production, or in the case of injection wells, put on injection. In some cases it may be desirable to leave the well shut in for a prolonged period of time, from several months to a year, following the treatment, before commencing production or water injection
Some oilfield brines already contain metal ions which may be effective for increasing the rate of hydrolysis of esters, either alone or in combination with an organic molecule or molecules. In some embodiments of the present invention it may therefore be possible to incorporate into the brine esters alone, or esters and if needed a suitable organic molecule or molecules capable of forming complexes with the metal ions present in the brines, to obtain useful rates of ester hydrolysis and acid production without having to add metal ions to the formulation. Similarly, some formations already contain metal ions which may be effective for increasing the rate of hydrolysis of esters, either alone or in combination with an organic molecule or molecules.
It is also possible to introduce the treatment fluid into the reservoir via coiled tubing or via bullheading of fluid. Irrespective of how the treatment fluid is introduced, it is possible for one or more components of it (the ester, the catalyst and/or the optional polymer breaker) to be in the form of a delayed release preparation.
The object of the method of the invention may, for instance, be to increase the rate of production of wells drilled into the formation, to increase the permeability of the formation, to remove filter cake, in particular following a gravel packing operation, or to remove a biofilm.
The present invention has the following particular advantages: The method provides a simple, effective and convenient way to acidise underground formations using a single fluid. The method may be used to increase the rate of ester hydeolysis to achieve acidising within a reduced period of time in situations where an enzyme is not effective due to temperature limitations or incompatibility with the base fluid, where use of an enzyme is not cost effective or where faster rates of ester hydrolysis in the absence of enzymes are sought.
The method also allows the successful incorporation of oxidant catalyst or enzyme polymer breakers into a treatment fluid able to deliver a high concentration of acid. Because the acid is present in a non,acidic precursor form, the breakers are not inactivated, as many would be by contact with conventional acids, and the activity of certain breakers is subsequently enhanced by the onset of moderate acidic conditions. This takes place after placement of the fluid, ensuring that both the acid and the breaker are delivered where they are needed.
As well as near wellbore or fracture face damage-removal the treatment fluid can also be used to achieve deep matrix stimulation during the same treatment. Because the fluid is essentially non-reactive when placed, excellent zonal coverage can be achieved.
Also the method is generally a very low hazard method compared to previous methods aiming to achieve a substantive degree of acidising. The method uses high flash point esters. There is generally no need for high pressure, high rate injection.
The components of the system are generally environmentally acceptable. The esters and enzymes and certain oxidant components such as the percarbonates are of low environmental impact. Also, the fluids are not highly corrosive, meaning that the use of corrosion inhibitors is generally not required which gives additional environmental benefits.

Method for treatment of underground reservoirs


A method of making an eyewear frame comprising the initial step of extruding an elongated billet of substantially rigid material having a top surface having predetermined convex cross-sectional initially as extruded curvature and a bottom surface having a predetermined concave cross-sectional initially as extruded curvature. The next step involves mounting a predetermined length of the elongated billet in a holding fixture of a computer numerical control (CNC) cutting machine. Next the CNC cutting machine is operated to cut out predetermined lens apertures and a finished eyewear frame around each of the previously machined lens apertures thereby producing a substantially stress free eyewear frame that is ready to have a stress free lens installed in its lens aperture.

The invention relates to eyewear frames and more specifically one whose front and rear surface curvatures remain substantially the same as their initial extruded curvature for the finished eyewear frame that has been cut out of an extruded billet of rigid material.
Eyewear frames encompass goggle frames, eyeglass frames and sunglasses frames. Most of the prior art eyewear frames are made of flexible plastic material. The lenses of these eyewear frames are normally flexed when installing them thereby producing internal stresses in the lenses and sometimes in the frames themselves. A major disadvantage of these assembled eyewear members is the fact that the stresses produce distortion in the lenses and the images viewed through the lenses are distorted. The use of metal frames for eyeglasses has been used for years. However these frames are not very strong and definitely not rigid and are often bent during use, when dropped, or by sitting or stepping on them. They are also rarely used with flexible plastic lenses.
About ten years ago an attempt was made to produce a rigid frame by forming it out of cast aluminum. This eyewear frame was the Briko snow ski goggle. It had a very thin flexible lens that had to be bent for insertion into the eyeframe and this curvature caused distortion of the images viewed by the wearer. Also its retention wall was very thin and often a blow to the frame caused the lens to pop out of the frame. It was definitely not a good design for impact type activities.
No one has designed and made a substantially rigid eyewear frame by using an extrusion process. Some of the applications for a rigid eyewear frame having a lens that would not pop out easily would be for paintball participants, military police, swat teams, the firearms shooting market, etc.
The Wilson U.S. Pat. No. 5,583,583 is directed to a metal frame for sunglasses and the method of making the same. A flat sheet of metal was cut in the predetermined shape of a sunglasses frame and it was heat treated in an annealing process to allow the frame to be bent into a predetermined concave curvature. It was heat treated to harden the material of the frame. An undesirable trait of this sunglass frame was that it would flex causing distortion of the lens and this was undesirable. Also when bent, the resulting radius was not constant.
It is an object of the invention to provide a novel rigid eyewear frame that can be used for goggles, eyeglasses and sunglasses.
It is also an object of the invention to provide a novel eyewear frame that begins as an extruded rigid billet of material such as metal or plastic.
It is also an object of the invention to provide a novel eyewear frame that has a rigid frame for receiving stress free lenses.
It is another object of the invention to provide an novel eyewear frame whose final configuration is substantially stress free since its curvature still remains substantially the same as when it was extruded.
It is a further object of the invention to provide a novel eyewear frame that has been designed for high impact activities and which has been designed so that its lens will not pop out easily upon impact.
It is also an object of the invention to provide a novel eyewear frame having structure that allows a stress free lens to be removably inserted therein and remain distortion free.
The novel method of manufacturing a stress free eyewear frame begins with the step of extruding a billet of rigid material from the extrusion die of an extrusion machine. The material could be a rigid aluminum alloy, a rigid titanium alloy, a hard plastic such as polycarbonate or other such acceptable materials having a petroleum base. If the material is a metal it would need a Rockwell hardness in the range of 20-110C. If the material is plastic it would have a Rockwell hardness in the range 80-130A.
As the billet of material is extruded, it has a top surface having a predetermined convex cross-sectional initially as extruded curvature and a bottom surface having a predetermined concave cross-sectional initially as extruded curvature. The length of the extruded billet could be as short as necessary in order to cut out only a single eyewear frame or it could be an extremely long, 50 feet or more, for cutting out multiple eyewear frames.
A predetermined length of the extruded billet would be attached to the holding fixture of a CNC machine capable of movement about at least 4 axes or as many as five axes. The CNC machine would have a turret head mill having a cutter mounted on one of its heads for milling the aperture of the eyewear frame. Another groove cutter would be mounted on another head for forming the groove in the lens aperture for receiving the lens. A cutter mounted on a mill head would also be used to cut the outer configuration of the eyewear frame. The eyewear frame would be substantially in its finished condition when it is removed from the holding fixture of the CNC machine or could be slightly altered by a bending press. Any small tab structure or rough edges along the outer edge of the eyewear frame can be easily removed. The resulting front surface of the finished eyewear frame would have the same predetermined convex cross-sectional initially as extruded curvature that it had in the initially extruded sheet. Likewise the rear surface of the finished eyewear frame would have the same predetermined concave cross-sectional initially as extruded curvature as found in the initially extruded sheet. Thus an eyewear frame has been produced free of any internal stresses such as would normally be found when forming an eyewear frame that requires a bending step to bring it to its final curvature. The eyewear frame could also be formed with two lens apertures.


An acidic hard surface liquid detergent with desirable cleansing and antibacterial properties comprises a C8-18 anionic surfactant, nonionic surfactants, a cosurfactant, water insoluble hydrocarbon, essential oil or perfume, a hydroxy aliphatic acid and/or salicylic acid and water.

This invention relates to an acidic all purpose liquid cleaning composition which can be in the form of a microemulsion designed in particular for cleaning hard surfaces and which is effective in removing particular and grease soil in leaving unrinsed surfaces with a shiny appearance.
This invention relates to an improved all-purpose liquid cleaning composition or a microemulsion composition designed in particular for cleaning hard surfaces and which is effective in removing grease soil and/or bath soil and in leaving unrinsed surfaces with a shiny appearance.
In recent years all-purpose liquid detergents have become widely accepted for cleaning hard surfaces, e.g., painted woodwork and panels, tiled walls, wash bowls, bathtubs, linoleum or tile floors, washable wall paper, etc.. Such all-purpose liquids comprise clear and opaque aqueous mixtures of water-soluble synthetic organic detergents and water-soluble detergent builder salts. In order to achieve comparable cleaning efficiency with granular or powdered all-purpose cleaning compositions, use of water-soluble inorganic phosphate builder salts was favored in the prior art all-purpose liquids. For example, such early phosphate-containing compositions are described in U.S. Pat. Nos. 2,560,839; 3,234,138; 3,350,319; and British Patent No.1,223,739.
In view of the environmentalist""s efforts to reduce phosphate levels in ground water, improved all-purpose liquids containing reduced concentrations of inorganic phosphate builder salts or non-phosphate builder salts have appeared. A particularly useful self-opacified liquid of the latter type is described in U.S. Pat. No. 4,244,840.
However, these prior art all-purpose liquid detergents containing detergent builder salts or other equivalent tend to leave films, spots or streaks on cleaned unrinsed surfaces, particularly shiny surfaces. Thus, such liquids require thorough rinsing of the cleaned surfaces which is a time-consuming chore for the user.
In order to overcome the foregoing disadvantage of the prior art all-purpose liquid, U.S. Pat. No. 4,017,409 teaches that a mixture of paraffin sulfonate and a reduced concentration of inorganic phosphate builder salt should be employed. However, such compositions are not completely acceptable from an environmental point of view based upon the phosphate content. On the other hand, another alternative to achieving phosphate-free all-purpose liquids has been to use a major proportion of a mixture of anionic and nonionic detergents with minor amounts of glycol ether solvent and organic amine as shown in U.S. Pat. No. 3,935,130. Again, this approach has not been completely satisfactory and the high levels of organic detergents necessary to achieve cleaning cause foaming which, in turn, leads to the need for thorough rinsing which has been found to be undesirable to today""s consumers.
Another approach to formulating hard surfaced or all-purpose liquid detergent composition where product homogeneity and clarity are important considerations involves the formation of oil-in-water (o/w) microemulsions which contain one or more surface-active detergent compounds, a water-immiscible solvent (typically a hydrocarbon solvent), water and a xe2x80x9ccosurfactantxe2x80x9d compound which provides product stability. By definition, an o/w microemulsion is a spontaneously forming colloidal dispersion of xe2x80x9coilxe2x80x9d phase particles having a particle size in the range of 25 to 800 xc3x85 in a continuous aqueous phase.
In view of the extremely fine particle size of the dispersed oil phase particles, microemulsions are transparent to light and are clear and usually highly stable against phase separation.
Patent disclosures relating to use of grease-removal solvents in o/w microemulsions include, for example, European Patent Applications EP 0137615 and EP 0137616 xe2x80x94Herbots et al; European Patent Application EP 0160762 xe2x80x94Johnston et al; and U.S. Pat. No. 4,561,991 xe2x80x94Herbots et al. Each of these patent disclosures also teaches using at least 5% by weight of grease-removal solvent.
It also is known from British Patent Application GB 2144763A to Herbots et al, published Mar. 13, 1985, that magnesium salts enhance grease-removal performance of organic grease-removal solvents, such as the terpenes, in o/w microemulsion liquid detergent compositions. The compositions of this invention described by Herbots et al. require at least 5% of the mixture of grease-removal solvent and magnesium salt and preferably at least 5% of solvent (which may be a mixture of water-immiscible non-polar solvent with a sparingly soluble slightly polar solvent) and at least 0.1% magnesium salt.
However, since the amount of water immiscible and sparingly soluble components which can be present in an o/w microemulsion, with low total active ingredients without impairing the stability of the microemulsion is rather limited (for example, up to 18% by weight of the aqueous phase), the presence of such high quantities of grease-removal solvent tend to reduce the total amount of greasy or oily soils which can be taken up by and into the microemulsion without causing phase separation.
The following representative prior art patents also relate to liquid detergent cleaning compositions in the form of o/w microemulsions: U.S. Pat. No. 4,472,291 xe2x80x94Rosario; U.S. Pat. No. 4,540,448 xe2x80x94Gauteer et al; U.S. Pat. No. 3,723,330 xe2x80x94Sheflin; etc.
Liquid detergent compositions which include terpenes, such as d-limonene, or other grease-removal solvent, although not disclosed to be in the form of o/w microemulsions, are the subject matter of the following representative patent documents: European Patent Application 0080749; British Patent Specification 1,603,047; and U.S. Pat. Nos. 4,414,128 and 4,540,505. For example, U.S. Pat. No. 4,414,128 broadly discloses an aqueous liquid detergent composition characterized by, by weight:
(a) from 1 % to 20% of a synthetic anionic, nonionic, amphoteric or zwitterionic surfactant or mixture thereof;
(b) from 0.5% to 10% of a mono- or sesquiterpene or mixture thereof, at a weight ratio of (a):(b) being in the range of 5:1 to 1:3; and
(c ) from 0.5% 10% of a polar solvent having a solubility in water at 150xc2x0 C. in the range of from 0.2% to 10%. Other ingredients present in the formulations disclosed in this patent include from 0.05% to 2% by weight of an alkali metal, ammonium or alkanolammonium soap of a C13-C24 fatty acid; a calcium sequestrant from 0.5% to 13% by weight; non-aqueous solvent, e.g., alcohols and glycol ethers, up to 10% by weight; and hydrotropes, e.g., urea, ethanolamines, salts of lower alkylaryl sulfonates, up to 10% by weight. All of the formulations shown in the Examples of this patent include relatively large amounts of detergent builder salts which are detrimental to surface shine.
Furthermore, the present inventors have observed that in formulations containing grease-removal assisting magnesium compounds, the addition of minor amounts of builder salts, such as alkali metal polyphosphates, alkali metal carbonates, nitrilotriacetic acid salts, and so on, tends to make it more difficult to form stable microemulsion systems.
U.S. Pat. No. 5,082,584 discloses a microemulsion composition having an anionic surfactant, a cosurfactant, nonionic surfactant, perfume and water; however, these compositions do not possess the ecotoxicity and the improved interfacial tension properties as exhibited by the compositions of the instant invention.
A number of patents teach esterified ethoxylated glycerol compounds for various applications. These patents are Great Britain 1,453,385; Japan 59-1600 and Japan 58-206693 and European Patent Application 0586,323A1. These publications fail to appreciate that a mixture of esterified ethoxylated glycerol and nonesterified ethoxylated glycerol, when used in a hard surface cleaning composition, functions as a grease release agent.
It has now been found that an acid hard surface liquid detergent can be formulated with an anionic surfactant which has desirable cleaning properties.
An object of this invention is to provide an acidic hard surface liquid detergent composition which can be in the form of a microemulsion, and comprises a sulfate and/or sulfonate anionic surfactant, a nonionic surfactant, an ethoxylated polyhydric alcohol type compound, magnesium sulfate, a glycol ether cosurfactant, a water insoluble organic compound, at least one hydroxy aliphatic acid and/or salicylic acid and water, wherein the composition does not contain any N-alkyl aldonamide, zwitterionic surfactant, silicas, abrasives, alkali metal carbonates, alkaline earth metal carbonates, alkyl glycine surfactant or a cyclic imidinium surfactant.
Another object of this invention is to provide an acidic hard surface liquid detergent with desirable cleaning properties which kills bacteria.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The microemulsion hard surface liquid compositions of the instant invention comprises approximately by weight:
(a) 0.1% to 20% of an alkali metal salt of an anionic surfactant;
(b) 0% to 10% of an ethoxylated polyhydric alcohol type compound;
(c) 0.1% to 10% of a nonionic surfactant;
(d) 0 to 5% of polyethylene glycol;
(e) 0 to 5% of at least one hydroxy aliphatic acid;
(f) 0.1% to 5% of salicylic acid;
(g) 0 to 10% of at least one solubilizing agent;
(h) 0.1% to 15% of at least one cosurfactant;
(i) 0 to 15% of an inorganic magnesium salt;
(j) 0.05% to 2% of a fatty acid;
(k) 0.1 % to 10% of perfume, essential oil, a water insoluble organic compound such as an ester or a water insoluble material such as terpene or essential oils;
(l) 0 to 5%, of a phenoxyalkanol;
(m) 0 to 2%, of a polymeric or inorganic thickener; and
(n) the balance being water.
The instant compositions do not contain an N-alkyl aldonamide, choline chloride or buffering system which is a nitrogenous buffer which is ammonium or alkaline earth carbonate, guanidine derivates, alkoxylalkyl amines and alkyleneamines C3-C7 alkyl and alkenyl monobasic and dibasic acids such as C4-C7 aliphatic carboxylic diacids which do not contain a hydroxy group, phosphoric acid, amino alkylene phosphonic acid and the composition is pourable and is not a gel and the composition has a complex viscosity at 1 rads-1 of less than 0.4 Pascal seconds.
The anionic sulfonate surfactants which may be used in the detergent of this invention are water soluble and include the sodium, potassium, ammonium and ethanolammonium salts of linear C8-C6 alkyl benzene sulfonates; C10-C20 paraffin sulfonates, alpha olefin sulfonates containing about 10-24 carbon atoms and C8-C18 ethoxylated alkyl ether sulfates and mixtures thereof. The preferred anionic sulfonate surfactant is a C12-18 paraffin sulfonate.
The paraffin sulfonates may be monosulfonates or di-sulfonates and usually are mixtures thereof, obtained by sulfonating paraffins of 10 to 20 carbon atoms. Preferred paraffin sulfonates are those of C12-18 carbon atoms chains, and more preferably they are of C14-17 chains. Paraffin sulfonates that have the sulfonate group(s) distributed along the paraffin chain are described in U.S. Pat. Nos. 2,503,280; 2,507,088; 3,260,744; and 3,372,188; and also in German Patent 735,096. Such compounds may be made to specifications and desirably the content of paraffin sulfonates outside the C14-17 range will be minor and will be minimized, as will be any contents of di- or poly-sulfonates.
Examples of suitable other sulfonated anionic detergents are the well known higher alkyl mononuclear aromatic sulfonates, such as the higher alkylbenzene sulfonates containing 9 to 18 or preferably 9 to 16 carbon atoms in the higher alkyl group in a straight or branched chain, or C8-15 alkyl toluene sulfonates. A preferred alkylbenzene sulfonate is a linear alkylbenzene sulfonate having a higher content of 3-phenyl (or higher) isomers and a correspondingly lower content (well below 50%) of 2-phenyl (or lower) isomers, such as those sulfonates wherein the benzene ring is attached mostly at the 3 or higher (for example 4, 5, 6 or 7) position of the alkyl group and the content of the isomers in which the benzene ring is attached in the 2 or 1 position is correspondingly low. Preferred materials are set forth in U.S. Pat. No. 3,320,174, especially those in which the alkyls are of 10 to 13 carbon atoms.
The C8-18 ethoxylated alkyl ether sulfate surfactants have the structure
Rxe2x80x94(OCHCH2)nOSO3xe2x88x92M+
wherein n is about 1 to about 22 more preferably 1 to 3 and R is an alkyl group having about 8 to about 18 carbon atoms, more preferably 12 to 15 and natural cuts, for example, C12-14 or C12-16 and M is an ammonium cation or a metal cation, most preferably sodium.
The ethoxylated alkyl ether sulfate may be made by sulfating the condensation product of ethylene oxide and C8-10 alkanol, and neutralizing the resultant product. The ethoxylated alkyl ether sulfates differ from one another in the number of carbon atoms in the alcohols and in the number of moles of ethylene oxide reacted with one mole of such alcohol. Preferred ethoxylated alkyl ether polyethenoxy sulfates contain 12 to 15 carbon atoms in the alcohols and in the alkyl groups thereof, e.g., sodium myristyl (3 EO) sulfate.
Ethoxylated C8-18 alkylphenyl ether sulfates containing from 2 to 6 moles of ethylene oxide in the molecule are also suitable for use in the invention compositions.
These detergents can be prepared by reacting an alkyl phenol with 2 to 6 moles of ethylene oxide and sulfating and neutralizing the resultant ethoxylated alkylphenol.
The water soluble nonionic surfactants which can be utilized in this invention are an aliphatic ethoxylated/propoxylated nonionic surfactants which are depicted by the formula:
wherein R is a branched chain alkyl group having about 10 to about 16 carbon atoms, preferably an isotridecyl group and x and y are independently numbered from 1 to 20. A preferred ethoxylated/propoxylated nonionic surfactant is Plurafac(copyright) 300 manufactured by BASF.
The instant composition contains a composition (herein after referred to as an ethoxylated polyhydric alcohol type compound such as an ethoxylated glycerol type compound) which is a mixture of a fully esterified ethoxylated polyhydric alcohol, a partially esterified ethoxylated polyhydric alcohol and a nonesterified ethoxylated polyhydric alcohol, wherein the preferred polyhydric alcohol is glycerol, and the compound is
and
wherein w equals one to four, most preferably one, and B is selected from the group consisting of hydrogen or a group represented by:
wherein R is selected from the group consisting of alkyl group having 6 to 22 carbon atoms, more preferably 11 to 15 carbon atoms and alkenyl groups having 6 to 22 carbon atoms, more preferably 11 to 15 carbon atoms, wherein a hydrogenated tallow alkyl chain or a coco alkyl chain is most preferred, wherein at least one of the B groups is represented by said
and Rxe2x80x2 is selected from the group consisting of hydrogen and methyl groups; x, y and z have a value between 0 and 60, more preferably 0 to 40, provided that (x+y+z) equals 2 to 100, preferably 4 to 24 and most preferably 4 to 19, wherein in Formula (I) the weight ratio of monoester / diester / triester is 40 to 90 / 5 to 35 / 1 to 20, more preferably 50 to 90/9 to 32 / 1 to 12, wherein the weight ratio of Formula (I) to Formula (II) is a value between 3 to 0.02, preferably 3 to 0.1, most preferably 1.5 to 0.2, wherein it is most preferred that there is more of Formula (II) than Formula (I) in the mixture that forms the compound.
The ethoxylated glycerol type compound used in the instant composition is manufactured by the Kao Corporation and sold under the trade name Levenol such as Levenol F-200 which has an average EO of 6 and a molar ratio of coco fatty acid to glycerol of 0.55 or Levenol V501/2 which has an average EO of 17 and a molar ratio of tallow fatty acid to glycerol of 1.0. It is preferred that the molar ratio of the fatty acid to glycerol is less than 1.7, more preferably less than 1.5 and most preferably less than 1.0. The ethoxylated glycerol type compound has a molecular weight of 400 to 1600, and a pH (50 grams / liter of water) of 5-7. The Levenol compounds are substantially non irritant to human skin and have a primary biodegradabillity higher than 90% as measured by the Wickbold method Bias-7d.
Two examples of the Levenol compounds are Levenol V-501/2 which has 17 ethoxylated groups and is derived from tallow fatty acid with a fatty acid to glycerol ratio of 1.0 and a molecular weight of 1465 and Levenol F-200 has 6 ethoxylated groups and is derived from coco fatty acid with a fatty acid to glycerol ratio of 0.55. Both Levenol F-200 and Levenol V-501/2 are composed of a mixture of Formula (I) and Formula (II). The Levenol compounds has ecoxicity values of algae growth inhibition  greater than  100 mg/liter; acute toxicity for Daphniae greater than 100 mg/liter and acute fish toxicity greater than 100 mg/liter. The Levenol compounds have a ready biodegradability higher than 60% which is the minimum required value according to OECD 301 B measurement to be acceptably biodegradable.
Polyesterified nonionic compounds also useful in the instant compositions are Crovol PK-40 and Crovol PK-70 manufactured by Croda GMBH of the Netherlands. Crovol PK-40 is a polyoxyethylene (12) Palm Kernel Glyceride which has 12 EO groups. Crovol PK-70 which is prefered is a polyoxyethylene (45) Palm Kernel Glyceride have 45 EO groups.
The at least one hydroxy aliphatic acid is used in the nonmicroemulsion or microemulsion composition at a concentration of about 0 wt. % to about 5 wt. %, more preferably about 0.1 wt. % to about 4 wt. %. The hydroxy aliphatic acid used in the instant composition is selected from the group consisting of glycolic acid, tartaric acid, citric acid and lactic acid 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 water immiscibility and 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 hydrocarbon such as a perfume is present in the dilute o/w microemulsion in an amount of from 0.4% to 10% by weight. If the amount of hydrocarbon (perfume) is less than 0.4% by weight it becomes difficult to form the o/w microemulsion. If the hydrocarbon (perfume) is added in amounts more than 10% by weight, the cost is increased without any additional cleaning benefit and, in fact, with some diminishing of cleaning performance insofar as the total amount of greasy or oily soil which can be taken up in the oil phase of the microemulsion will decrease proportionately.
Furthermore, although superior grease removal performance will be achieved for perfume compositions not containing any terpene solvents, it is apparently difficult for perfumers to formulate sufficiently inexpensive perfume compositions for products of this type (i.e., very cost sensitive consumer-type products) which includes less than 20%, usually less than 30%, of such terpene solvents.
Thus, merely as a practical matter, based on economic consideration, the dilute microemulsion detergent cleaning compositions of the present invention may often include as much as 0.2% to 7% by weight, based on the total composition, of terpene solvents introduced thereunto via the perfume component. However, even when the amount of terpene solvent in the cleaning formulation is less than 1.5% by weight, such as up to 0.6% by weight or 0.4% by weight or less, satisfactory grease removal and oil removal capacity is provided by the inventive diluted o/w microemulsions.
Thus, for a typical formulation of a diluted microemulsion according to this invention a 20 milliliter sample of microemulsion containing 1 % by weight of perfume will be able to solubilize, for example, up to 2 to 3 ml of greasy and/or oily soil, while retaining its form as a microemulsion, regardless of whether the perfume contains 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% or 0.8% by weight of terpene solvent. In other words, it is an essential feature of the compositions of this invention that grease removal is a function of the result of the microemulsion, per se, and not of the presence or absence in the microemulsion of a xe2x80x9cgreasy soil removalxe2x80x9d type of solvent.
In place of the perfume in either the microemulsion composition or the all purpose hard surface cleaning composition at the same previously defined concentrations that the perfume was used in either the microemulsion or the all purpose hard surface cleaning composition one can employ an essential oil or a water insoluble hydrocarbon having 6 to 18 carbon such as a paraffin or isoparaffin.
Suitable essential oils are selected from the group consisting of: Anethole 20/21 natural, Aniseed oil china star, Aniseed oil globe brand, Balsam (Peru), Basil oil (India), Black pepper oil, Black pepper oleoresin 40/20, Bois de Rose (Brazil) FOB, Borneol Flakes (China), Camphor oil, White, Camphor powder synthetic technical, Cananga oil (Java), Cardamom oil, Cassia oil (China), Cedarwood oil (China) BP, Cinnamon bark oil, Cinnamon leaf oil, Citronella oil, Clove bud oil, Clove leaf, Coriander (Russia), Coumarin 69xc2x0 C. (China), Cyclamen Aldehyde, Diphenyl oxide, Ethyl vanilin, Eucalyptol, Eucalyptus oil, Eucalyptus citriodora, Fennel oil, Geranium oil, Ginger oil, Ginger oleoresin (India), White grapefruit oil, Guaiacwood oil, Gurjun balsam, Heliotropin, Isobornyl acetate, Isolongifolene, Juniper berry oil, L-methyl acetate, Lavender oil, Lemon oil, Lemongrass oil, Lime oil distilled, Litsea Cubeba oil, Longifolene, Menthol crystals, Methyl cedryl ketone, Methyl chavicol, Methyl salicylate, Musk ambrette, Musk ketone, Musk xylol, Nutmeg oil, Orange oil, Patchouli oil, Peppermint oil, Phenyl ethyl alcohol, Pimento berry oil, Pimento leaf oil, Rosalin, Sandalwood oil, Sandenol, Sage oil, Clary sage, Sassafras oil, Spearmint oil, Spike lavender, Tagetes, Tea tree oil, Vanilin, Vetyver oil (Java), Wintergreen, Allocimene, Arbanex(trademark), Arbanol(copyright), Bergamot oils, Camphene, Alpha-Campholenic aldehyde, I-Carvone, Cineoles, Citral, Citronellol Terpenes, Alpha-Citronellol, Citronellyl Acetate, Citronellyl Nitrile, Para-Cymene, Dihydroanethole, Dihydrocarveol, d-Dihydrocarvone, Dihydrolinalool, Dihydromyrcene, Dihydromyrcenol, Dihydromyrcenyl Acetate, Dihydroterpineol, Dimethyloctanal, Dimethyloctanol, Dimethyloctanyl Acetate, Estragole, Ethyl-2 Methylbutyrate, Fenchol, Fernlol(trademark), Florilys(trademark), Geraniol, Geranyl Acetate, Geranyl Nitrile, Glidmint(trademark) Mint oils, Glidox(trademark), Grapefruit oils, trans-2-Hexenal, trans-2-Hexenol, cis-3-Hexenyl Isovalerate, cis-3-Hexanyl-2-methylbutyrate, Hexyl Isovalerate, Hexyl-2-methylbutyrate, Hydroxycitronellal, lonone, Isobornyl Methylether, Linalool, Linalool Oxide, Linalyl Acetate, Menthane Hydroperoxide, I-Methyl Acetate, Methyl Hexyl Ether, Methyl-2-methylbutyrate, 2-Methylbutyl Isovalerate, Myrcene, Nerol, Neryl Acetate, 3-Octanol, 3-Octyl Acetate, Phenyl Ethyl-2-methylbutyrate, Petitgrain oil, cis-Pinane, Pinane Hydroperoxide, Pinanol, Pine Ester, Pine Needle oils, Pine oil, alpha-Pinene, beta-Pinene, alpha-Pinene Oxide, Plinol, Plinyl Acetate, Pseudo lonone, Rhodinol, Rhodinyl Acetate, Spice oils, alpha-Terpinene, gamma-Terpinene, Terpinene-4-OL, Terpineol, Terpinolene, Terpinyl Acetate, Tetrahydrolinalool, Tetrahydrolinalyl Acetate, Tetrahydromyrcenol, Tetralol(copyright), Tomato oils, Vitalizair, Zestoral(trademark).
The polyethylene glycol which can be used in the instant composition has a molecular weight of 200 to 1,000, wherein the polyethylene glycol has the structure
HO(CH2CH2O)nH
wherein n is 4 to 25. The concentration of the polyethylene glycol in the instant composition is 0 to 5 wt. %, more preferably 0.1 to 4.0 wt. %. The phenoxyalkanol which is used at a concentration of 0 to 5 wt. %, more preferably 0.25 to 4.0 wt. % is depicted by the formula:
C6H5O(CH2)nCH2OH
wherein n is 1 to 3, preferably 1.
The instant all purpose cleaning compositions contain about 0 wt. % to about 10 wt. %, of at least one solubilizing agent selected from the group consisting of a C2-5 mono, dihydroxy or polyhydroxy alkanols such as ethanol, isopropanol, glycerol ethylene glycol, diethylene glycol and propylene glycol and mixtures thereof and alkali metal cumene or xylene sulfonates such as sodium cumene sulfonate and sodium xylene sulfonate. The solubilizing agents are included in order to control low temperature cloud clear properties.
The cosurfactant used in the microemulsion composition may play an essential role in the formation of the microemulsion compositions. Very briefly, in the absence of the cosurfactant the water, detergent(s) and hydrocarbon (e.g., perfume) will, when mixed in appropriate proportions form either a micellar solution (low concentration) or form an oil-in-water emulsion in the first aspect of the invention. With the cosurfactant added to this system, the interfacial tension at the interface between the emulsion droplets and aqueous phase is reduced to a very low value. This reduction of the interfacial tension results in spontaneous break-up of the emulsion droplets to consecutively smaller aggregates until the state of a transparent colloidal sized emulsion. e.g., a microemulsion, is formed. In the state of a microemulsion, thermodynamic factors come into balance with varying degrees of stability related to the total free energy of the microemulsion. Some of the thermodynamic factors involved in determining the total free energy of the system are (1) particle-particle potential; (2) interfacial tension or free energy (stretching and bending); (3) droplet dispersion entropy; and (4) chemical potential changes upon formation. A thermodynamically stable system is achieved when (2) interfacial tension or free energy is minimized and (3) droplet dispersion entropy is maximized.
Thus, the role of cosurfactant in formation of a stable o/w microemulsion is to (a) decrease interfacial tension (2); and (b) modify the microemulsion structure and increase the number of possible configurations (3). Also, the cosurfactant will (c) decrease the rigidity. Generally, an increase in cosurfactant concentration results in a wider temperature range of the stability of the product.
The major class of compounds found to provide highly suitable cosurfactants for the microemulsion over temperature ranges extending from 50xc2x0 C. to 43xc2x0 C. for instance are polypropylene glycol of the formula HO(CH3CHCH2O)nH wherein n is a number from 1 to 18, and mono and di C1-C6 alkyl ethers and esters of ethylene glycol and propylene glycol having the structural formulas R(X)nOH, R1(X)nOH, R(X)nOR and R1(X)nOR1 wherein R is C1-C6 alkyl group, R1 is C2-C4 acyl group, X is (OCH2CH2) or (OCH2(CH3)CH) and n is a number from 1 to 4, diethylene glycol, triethylene glycol, an alkyl lactate, wherein the alkyl group has 1 to 6 carbon atoms, 1 methoxy-2-propanol, 1 methoxy-3-propanol, and 1 methoxy 2-, 3- or 4-butanol.
Representative members of the polypropylene glycol include dipropylene glycol and polypropylene glycol having a molecular weight of 150 to 1000, e.g., polypropylene glycol 400. Other satisfactory glycol ethers are ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol monobutyl ether, mono, di, tri propylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, mono, di, tripropylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, propylene glycol tertiary butyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monopropyl ether, ethylene glycol monopentyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monopentyl ether, triethylene glycol monohexyl ether, mono, di, tripropylene glycol monoethyl ether, mono, di tripropylene glycol monopropyl ether, mono, di, tripropylene glycol monopentyl ether, mono, di, tripropylene glycol monohexyl ether, mono, di, tributylene glycol mono methyl ether, mono, di, tributylene glycol monoethyl ether, mono, di, tributylene glycol monopropyl ether, mono, di, tributylene glycol monobutyl ether, mono, di, tributylene glycol monopentyl ether and mono, di, tributylene glycol monohexyl ether, ethylene glycol monoacetate and dipropylene glycol propionate. When these glycol type cosurfactants are at a concentration of about 0.5 to about 14 weight %, more preferably about 2.0 weight % to about 10 weight % in combination with a water insoluble organic ester or non water soluble material such as terpene, essential oils which is at a concentration of at least 0.5 weight %, more preferably 1.5 weight % to about 8 wt. % one can form a microemulsion composition.
While all of the aforementioned glycol ether compounds provide the described stability, the most preferred cosurfactant compounds of each type, is diethylene glycol monobutyl ether. Other suitable water soluble cosurfactants are water soluble esters such as ethyl lactate and water soluble carbohydrates such as butyl glycosides.
The instant microemulsion formulas explicitly exclude alkali metal silicates and alkali metal builders such as alkali metal polyphosphates, alkali metal carbonates and alkali metal phosphonates because these materials, if used in the instant composition, would cause the composition to have a high pH as well as leaving residue on the surface being cleaned.
The final essential ingredient in the inventive microemulsion or nonmicroemulsion compositions having improved interfacial tension properties is water. The proportion of water in the compositions generally is in the range of 50% to 96%, preferably 80% to 90% by weight of the usual diluted o/w microemulsion composition.
In addition to the above-described essential ingredients required for the formation of the microemulsion composition, the compositions of this invention may often and preferably do contain one or more additional ingredients which serve to improve overall product performance.
One such ingredient is an inorganic or organic salt of oxide of a multivalent metal cation, particularly Mg++. The metal salt or oxide provides several benefits including improved cleaning performance in dilute usage, particularly in soft water areas, and minimized amounts of perfume required to obtain the microemulsion state.
Magnesium sulfate, either anhydrous or hydrated (e.g., heptahydrate), is especially preferred as the magnesium salt. Good results also have been obtained with magnesium oxide, magnesium chloride, magnesium acetate, magnesium propionate and magnesium hydroxide. These magnesium salts can be used with formulations at neutral or acidic pH since magnesium hydroxide will not precipitate at these pH levels.
Although magnesium is the preferred multivalent metal from which the salts (inclusive of the oxide and hydroxide) are formed, other polyvalent metal ions also can be used provided that their salts are nontoxic and are soluble in the aqueous phase of the system at the desired pH level.
The compositions will include from 0% to 2.5%, preferably from 0.1% to 2.0% by weight of the composition of a C8-C22 fatty acid or fatty acid soap as a foam suppressant.
The addition of fatty acid or fatty acid soap provides an improvement in the rinseability of the composition whether applied in neat or diluted form. Generally, however, it is necessary to increase the level of cosurfactant to maintain product stability when the fatty acid or soap is present. If more than 2.5 wt. % of a fatty acid is used in the instant compositions, the composition will become unstable at low temperatures as well as having an objectionable smell.
As example of the fatty acids which can be used as such or in the form of soap, mention can be made of distilled coconut oil fatty acids, xe2x80x9cmixed vegetablexe2x80x9d type fatty acids (e.g. high percent of saturated, mono-and/or polyunsaturated C18 chains); oleic acid, stearic acid, palmitic acid, eiocosanoic acid, and the like, generally those fatty acids having from 8 to 22 carbon atoms being acceptable.
Thus, depending on such factors as the pH of the system, the nature of the primary surfactants and cosurfactant, and so on, as well as the availability and cost factors, other suitable polyvalent metal ions include aluminum, copper, nickel, iron, calcium, etc. It should be noted, for example, that with the preferred paraffin sulfonate anionic detergent calcium salts will precipitate and should not be used. It has also been found that the aluminum salts work best at pH below 5 or when a low level, for example 1 weight percent, of citric acid is added to the composition which is designed to have a neutral pH. Alternatively, the aluminum salt can be directly added as the citrate in such case. As the salt, the same general classes of anions as mentioned for the magnesium salts can be used, such as halide (e.g., bromide, chloride), sulfate, nitrate, hydroxide, oxide, acetate, propionate, etc.
Preferably, in the dilute compositions the metal compound is added to the composition in an amount sufficient to provide at least a stoichiometric equivalent between the anionic surfactant and the multivalent metal cation. For example, for each gram-ion of Mg++ there will be 2 gram moles of paraffin sulfonate, alkylbenzene sulfonate, etc., while for each gram-ion of Al3+there will be 3 gram moles of anionic surfactant. Thus, the proportion of the multivalent salt generally will be selected so that one equivalent of compound will neutralize from 0.1 to 1.5 equivalents, preferably 0.6 to 1.4 equivalents, of the acid form of the anionic surfactant. At higher concentrations of anionic surfactant, the amount of the inorganic magnesium salt will be in range of 0 to 5 wt. %, more preferably 0.5 to 3 wt. %.
The liquid 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% by weight; preservatives or antioxidizing agents, such as formalin, 5-bromo-5-nitro-dioxan-1,3; 5-chloro-2-methyl-4-isothaliazolin-3-one, 2,6-di-tert.butyl-p-cresol, etc., in amounts up to 2% by weight; and pH adjusting agents, such as sulfuric acid or sodium hydroxide, as needed. Furthermore, if opaque compositions are desired, up to 4% by weight of an opacifier may be added.
In final form, the instant compositions exhibit stability at reduced and increased temperatures. More specifically, such compositions remain clear and stable in the range of 5xc2x0 C. to 50xc2x0 C., especially 10xc2x0 C. to 43xc2x0 C. Such compositions exhibit a pH of 3 to 7.0 which is achieved by the addition of caustic soda or alkanolamide. The liquid microemulsion compositions are readily pourable and exhibit a viscosity in the range of 6 to 400 milliPascal . second (mPas.) as measured at 250xc2x0 C. with a Brookfield RVT Viscometer using a #2 spindle rotating at 50 RPM.
The following examples illustrate liquid cleaning compositions of the described invention. Unless otherwise specified, all percentages are by weight. The exemplified compositions are illustrative only and do not limit the scope of the invention. Unless otherwise specified, the proportions in the examples and elsewhere in the specification are by weight.

Acidic all purpose liquid cleaning compositions


A ball valve gasket structure includes a housing base having an accommodating area and a position limit area; a leakproof washer installed in the position limit area; a ring-shaped slide unit having a ring-shaped steel plate and a ring-shaped graphite plate installed in the accommodating area, and both top and bottom sides are ring-shaped steel plates of the slide unit, and the ring-shaped steel plate at the bottom side abuts the bottom of the accommodating area, and the other ring-shaped slide unit has an arc surface portion disposed at the internal periphery; and a cover coupled to the housing base for sealing the slide unit. The ball valve gasket structure can be used together with a ball valve to achieve the slide assisting effect, improving service life, and facilitating installation and disassembly.

In general, a conventional ball valve gasket is installed between a valve and a ball to provide a slide assisting effect during the use of the ball valve gasket, and the conventional gasket is mainly divided into two types, respectively: a metal gasket and a non-metal gasket.
However, the non-metal gasket comes with less strength and rigidity and thus may be damaged easily when it is used under the conditions of high temperature and high pressure for a long time. On the other hand, although the metal gasket can overcome the aforementioned drawback of the non-metal gasket, the metal gasket and the ball are rubbed with each other, so that the gasket and the ball may be worn out or damaged easily. In addition, such gasket cannot be replaced by itself, but it is necessary to replace the whole set of gasket and ball in order to maintain the air tightness effectively. Obviously, the non-metal or metal gasket cannot meet the requirement for the slide assisting effect or achieve the effects of extending the service life of the gasket or installing and removing the gasket easily. In addition, the manufacture of the metal gasket requires a more complicated procedure and takes a longer time.
Therefore, it is a main subject of the present invention to provide a ball valve gasket structure that can achieve the slide assisting effect, improve service life, and facilitate installation, disassembly and manufacture.