ENZYMATIC LIQUID CLEANING COMPOSITION

Abstract: An aqueous liquid or gel type detergent composition comprises (a) from about 0.1 % to about 15 % by weight, boric acid or a boron compound; (b) from about 0.1 % to about 10 % by weight, a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, 1,2-propanediol, butylene glycol, hexylene glycol, glycerol, mannitol, sorbitol, erythritol, glucose, fructose, lactose, erythritol-1,4-anhydride, and mixtures thereof; and (c) an oxygen bleach resistant alpha -amylase enzyme and (d) from about 5 % to about 80 % water.

Description: ENZYMATIC LIQUID CLEANING COMPOSITION TECHNICAL FIELD The present invention relates to aqueous liquid or gel type detergent compositions. More particularly, the invention relates to aqueous liquid or gel type detergent compositions exhibiting enhanced α-amylase enzyme stability by using a combination of an oxygen bleach resistant α-amylase enzyme, boric acid or a boron compound capable of forming boric acid in the composition, and a polyhydroxy compound, preferably propanediol, even with the exclusion of alkali metal sulfites. The invention also relates to a process for enhancing stability of an α-amylase enzyme in a liquid or gel detergent. BACKGROUND OF THE INVENTION Aqueous liquid enzymatic detergent compositions are well known in the art. The major problem encountered with such compositions is that of ensuring a sufficient storage stability of the enzymes in these compositions. It is desirable to enhance the stability of amylase enzymes, particularly in the presence of protease enzymes which can degrade amylases, in aqueous liquid or gel type detergent compositions. High-alkaline amylases, such as alpha amylases are described in British Specification No. 1,296,839, assigned to Novo, incorporated herein by reference. The use of an enzyme stabilizing system comprising a mixture of boric acid or an alkali metal borate with a polyol or a polyfunctional amino compound, together with a certain high level of a reducing alkali metal salt such as sodium sulphite, is known and disclosed in U.S. Patent 4,462,922, incorporated herein by reference. However it has been desirable to attain enzyme stability of amylase enzymes without resorting to the use of alkali metal sulphites in combination with boric acid and polyhydroxy compounds. It has also been desirable to use boric acid rather than alkali metal borates and still obtain a high degree of enzyme stability. It has been desirable to have an alkali metal sulphite free system which includes the use of a specific type of an amylase enzyme which is stable to oxygen bleach and degradation, as compared to other amylases such as Termamyl. It has been desirable to use low levels of boric acid and propanediol, and a low to zero level of alkali metal sulphite, because a low level of these components helps improve the transluscency and transparency of the liquid or gel detergent composition. However, in the past it has been understood that low levels of one or more of the aforementioned boric acid, diol and alkali metal sulphite may not provide adequate enzyme stability. The present invention utilizes low levels of the aforementioned components in combination while surprisingly enhancing enzyme stability. The present invention is thus directed to overcome one or more of the problems as set forth before. BACKGROUND ART U.S. Patent No. 4,462,922, issued to Boskamp, Jelles V., and assigned to Lever Brothers Company, discloses an enzyme stabilizing system comprising a mixture of boric acid or an alkali metal borate with a polyol or a polyfunctional amino compound, together with a certain level of a reducing alkali metal salt such as sodium sulphite. U.S. Patent No. 4,404,1 15, issued to Tai, Ho T., and assigned to Lever Brothers Company, discloses an enzymatic liquid cleaning composition, comprising an enzyme stabilizing system including an alkali metal borate, alkali metal sulphite and a polyol. SUMMARY OF THE INVENTION The invention meets the needs above by providing an aqueous liquid or gel type detergent composition, and a process for stabilizing an amylase enzyme in an aqueous enzymatic liquid or gel detergent composition. Such detergent compositions are useful for cleaning tableware (i.e., glassware, china, silverware, plastic, etc.), kitchenware, household surfaces such as floors, bathroom fixtures and countertops, and fabrics. The compositions may be fully formulated cleaning products or they may be additive or specialty products that can be used alone or with other cleaning products. Particularly preferred compositions herein are for use in automatic dishwashing machines. In one aspect of the present invention, an aqueous liquid or gel type detergent composition comprises (a) from about 0.1% to about 15% by weight of boric acid or a boron compound capable of forming boric acid in the composition; (b) from about 0.1% to about 10%) by weight of a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, 1,2-propanediol, butylene glycol, hexylene glycol, glycerol, mannitol, sorbitol, erythritol, glucose, fructose, lactose, erythritol- 1 ,4-anhydride, and mixtures thereof; and (c) an oxygen bleach resistant α- amylase enzyme and (d) from about 5% to about 80% water. In another aspect of the present invention, a process for stabilizing an amylase enzyme in an aqueous enzymatic liquid or gel type detergent composition comprises mixing; (a) from about 0.1% to about 15% by weight, of boric acid or a boron compound capable of forming boric acid in the composition; (b) from about 0.1 % to about 10% by weight, a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, 1,2-propanediol, butylene glycol, hexylene glycol, glycerol, mannitol, sorbitol, erythritol, glucose, fructose, lactose, erythritol- 1 ,4-anhydride, and mixtures thereof; and (c) an oxygen bleach resistant α-amylase enzyme; with detergent ingredients. DETAILED DESCRIPTION OF THE INVENTION In the preferred embodiment of the present invention, an aqueous liquid or gel type detergent composition comprises (a) from about 0.1% to about 15% by weight, of boric acid or a boron compound capable of forming boric acid in the composition; (b) from about 0.1% to about 10% by weight, of a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, 1,2-propanediol, butylene glycol, hexylene glycol, glycerol, mannitol, sorbitol, erythritol, glucose, fructose, lactose, erythritol- 1 ,4-anhydride, and mixtures thereof; and (c) an oxygen bleach resistant α- amylase enzyme, and (d) from about 5% to about 80%, preferably from about 20% to about 80%, more preferably from about 40% to about 70%, by weight of water. In the preferred embodiment, the boric acid or boron compound capable of forming boric acid in the composition, is desirably present in an amount from about 0.5% to about 10% by weight, and preferably from about 1% to about 5%, and more preferably from about 2% to about 4% by weight (calculated on the basis of boric acid present). Boric acid is particularly preferred herein, although other compounds such as boric oxide, borax and other alkali metal borates (e.g., sodium ortho-, meta-, and pyroborate, and sodium pentaborate) are suitable. Substituted boric acids (e.g., phenylboronic acid, butane boronic acid, and p-bromo phenylboronic acid) can also be used in place of boric acid. The compositions of the present invention also contain a polyhydroxy compound as described above. The polyhydroxy compound preferably contains from 2 to 6 carbon atoms and from 2 to 6 hydroxy groups, and is preferably selected from propylene glycol, ethylene glycol, glycerol, sorbitol, and glucose, and mixtures thereof. The polyhydroxy compound is preferably 1,2-propanediol. In the preferred embodiment, the polyhydroxy compound is desirably present in an amount from about 0.1% to about 7% by weight, preferably from about 0.1% to about 5% by weight, and more preferably, from about 0.1% to about 1% by weight. Most preferably, the polyhydroxy compound is present at a level of from about 0.2% to about 1% by weight. The compositions of the present invention also contain from about 0.01% to about 5%, preferably from about 0.1% to about 2%, by weight of an oxygen bleach resistant α- amylase enzyme. Such amylases include variants having additional modification as described in WO 9510603 A, incorporated herein by reference, and are available from Novo as DURAMYL ® . Other particularly preferred oxidative stability enhanced amylases include those described in WO 9418314 to Genencor International and WO 9402597 to Novo, both incorporated by reference. In the preferred embodiment, the amylase is the oxygen bleach resistant α-amylase enzyme available commercially from Novo under the trade name Duramyl. In the present invention, it has most surprisingly been found that contrary to the teachings of the art in this field of endeavor, even by excluding alkali metal sulphites, by combining the aforementioned levels of boric acid or boron compound and polyhydroxy compound such as propanediol with an oxygen bleach resistant α-amylase enzyme, a better enzyme stabilizing formulation results. The formulation is very effective in stabilizing oxygen bleach resistant α-amylase enzymes such as Duramyl, as compared to other α-amylase enzymes such as Termamyl. The composition may optionally include other enzymes, including mixtures of proteases and amylases. But it has been demonstrated that a combination of the Duramyl oxygen bleach resistant α-amylase enzyme, boric acid and polyhydroxy compound, when added to other detergent ingredients, results in a detergent composition which exhibits a high degree of enzyme stability as compared to a similar composition containing the Termamyl α-amylase. This is indeed a surprising discovery and claimed henceforth in this invention. Other detergent ingredients The compositions of the invention may also contain additional components generally found in detergent compositions. The compositions may contain surfactants, especially anionic and or nonionic surfactants, solvents, clay, polycarboxylate thickeners, baking soda, brighteners, carbonates, phosphates, dicarboxylic acid, siloxanes, perfumes, bleach and bleach catalysts, and mixtures thereof. Preferred components are discussed in more detail hereafter. (a) Thickeners The physical stability of the liquid product may be improved and the thickness of the liquid product may be altered by the addition of a cross-linking polyacrylate thickener to the liquid detergent product as a thixotropic thickener. Thickeners for use herein include those selected from clay, polycarboxylates, such as Polygel ® , gums, carboxymethyl cellulose, polyacrylates, and mixtures thereof. The preferred clay type herein has a double-layer structure. The clay may be naturally occurring, e.g., Bentonites, or artificially made, e.g., Laponite ® . Laponite ® is supplied by Southern Clay Products, Inc. See The Chemistry and Physics of Clays, Grimshaw, 4 th ed., 1971, pages 138-155, Wiley-Interscience. (b) PH adjusting components The above liquid detergent product is preferably low foaming, readily soluble in the washing medium and most effective at pH values best conducive to improved cleaning performance, such as in a range of desirably from about pH 6.5 to about pH 12.5, and preferably from about pH 7.0 to about pH 12.0, more preferably from about pH 8.0 to about pH 12.0. Preferably the pH is less than about 10.0 for better enzyme stability most preferably less than about 9.0. The pH adjusting components are desirably selected from sodium or potassium hydroxide, sodium or potassium carbonate or sesquicarbonate, sodium or potassium silicate, boric acid, sodium or potassium bicarbonate, sodium or potassium borate, and mixtures thereof. NaOH or KOH are the preferred ingredients for increasing the pH to within the above ranges. Other preferred pH adjusting ingredients are sodium carbonate, potassium carbonate, and mixtures thereof, (c) Low Foaming Surfactant Non-chlorine bleach-containing liquid ADW compositions of the present invention preferably contain a nonionic surfactant, preferably an alkyl ethoxylate surfactant. One example of a non-chlorine bleach stable surfactant is SLF18® manufactured by BASF Corporation. Alternatively, in chlorine bleach containing liquid ADW compositions, chlorine bleach stable low foaming surfactants are preferred and such surfactants are present in a range of from about 0.1% to about 10% by weight of the liquid composition. Such surfactants are generally known to one skilled in the art and need not be elaborated here, for purposes of brevity. An example of a chlorine bleach stable surfactant is Dowfax® anionic surfactant available from the Dow Chemical Company. Surfactants useful herein are described in more detail in WO 98/03622, published January 29, 1998, incorporated herein by reference. (d) Builder The compositions of the present invention also preferably contain one or more detergent builders to assist in controlling mineral hardness and in the removal of particulate soils. Inorganic as well as organic builders can be used. The level of builder can vary widely depending upon the end use of the composition and its desired physical form. When present, the compositions will typically comprise at least about 1% builder. Liquid formulations typically comprise from about 5% to about 50%, more typically about 5% to about 30%, by weight, of detergent builder. Lower or higher levels of builder, however, are not meant to be excluded. Inorganic or P-containing detergent builders include, but are not limited to, the alkali metal, ammonium and alkanolammonium slats of polyphosphates (exemplified by the tripolyphosphates, and glassy polymeric meta-phosphates), phosphonates, phytic acid, silicates, carbonates (including bicarbonates and sesquicarbonates), sulphates, and aluminosilicates. Examples of silicate builders are the alkali metal silicates, particularly those having a SiO 2 :Na 2 O ratio in the range 1.6: 1 to 3.2: 1 and layered silicates, such as the layered sodium silicates described in U.S. Patent 4,664,839, issued May 12, 1987 to H. P. Rieck. NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly abbreviated herein as "SKS-6"). NaSKS-6 can be prepared by methods such as those described in German DE-A-3 ,417,649 and DE-A-3,742,043. Other layered silicates, such as those having the general formula NaMSi x O 2x+] -yH 2 O wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to 20 can be used herein. Various other layered silicates from Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, as the alpha, beta and gamma forms. Examples of carbonate builders are the alkaline earth and alkali metal carbonates as disclosed in German Patent Application No. 2,321,001 published on November 15, 1973. Aluminosilicate builders may be useful in the present invention. Aluminosilicate builders include those having the empirical formula: M z (zAlO 2 )y]xH 2 O wherein z and y are integers of at least 6, the molar ratio of z to y is in the range from 1.0 to about 0.5, and x is an integer from about 15 to about 264. Useful aluminosilicate ion exchange materials are commercially available. A method for producting aluminosilicate ion exchange materials is disclosed in U.S. Patent 3,985,669, Krummel, et al, issued October 12, 1976. Preferred synthetic crystalline aluminosilicate ion exchange materials useful herein are available under the designations Zeolite A, Zeolite P (B), Zeolite MAP and Zeolite X. In an especially preferred embodiment, the crystalline aluminosilicate ion exchange material has the formula: Na 12 [AlO 2 ) 12 (SiO 2 ) 12 ] xH 2 O wherein x is from about 20 to about 30, especially about 27. This material is know as Zeolite A. Dehydrated zeolites (x = 0 - 10) may also be used herein. Preferably, the aluminosilicate has a particle size of about 0.1-10 microns in diameter. Organic detergent builders suitable for the purposes of the present invention include, but are not restricted to, a wide variety of polycarboxylate compounds. As used herein, "polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably at least 3 carboxylates. Polycarboxylate builder can generally be added to the composition in acid form, but can also be added in the form of a neutralized salt. When utilized in salt form, alkali metals, such as sodium, potassium, and lithium, or alkanolammonium salts are preferred. Included among the polycarboxylate builders are a variety of categories of useful materials. One important category of polycarboxylate builders encompasses the ether polycarboxylates, including oxydisuccinate, as disclosed in Berg, U.S. Patent 3,128,287, issued April 7, 1964, and Lamberti et al, U.S. Patent 3,635,830, issued January 18, 1972. See also "TMS/TDS" builders of U.S. Patent 4,663,071, issued to Bush et al, on May 5, 1987. Suitable ether polycarboxylates also include cyclic compounds, particularly alicyclic compounds, such as those described in U.S. Patents 3,923,679; 3,835,163; 4,158,635; 4,120,874 and 4,102,903. Citrate builders, e.g., citric acid and soluble salts thereof (particularly sodium salt), are polycarboxylate builders of importance for liquid detergent formulations due to their availability from renewable resources and their biodegradability. Oxydisuccinates are also especially useful in such compositions and combinations. Also suitable in the compositions of the present invention are the 3,3-dicarboxy-4- oxa- 1 ,6-hexanedioates and the related compounds disclosed in U.S. Patent 4,566,984, Bush, issued January 28, 1986. Laurylsuccinates are the preferred builders of this group, and are described in European Patent Application 86200690.5/0,200,263, published November 5, 1986. Other suitable polycarboxylates are disclosed in U.S. Patent 4,144,226, Crutchfield et al, issued March 13, 1979 and in U.S. Patent 3,308,067, Diehl, issued March 7, 1967. See also Diehl U.S. Patent 3,723,322. Fatty acids, e.g., C 12 -C 18 monocarboxylic acids, can also be incorporated into the compositions alone, or in combination with the aforesaid builders, especially citrate and or the succinate builders, to provide additional builder activity. (e) Other adjunct detergent ingredients The liquid or gel detergent composition may optionally contain up to about 20% of a dispersant polymer selected from the group consisting of polyacrylates and polyacrylate copolymers. The compositions of the present invention may also contain other enzymes and enzyme stabilizing agents such as calcium ion and short chain carboxylic acids as disclosed in WO 98/03622, published January 29, 1998, U.S. Patent 4,537,707, Severson, and U.S. Patent 4,318,818, Letton, et. al., all incorporated herein by reference. The compositions herein may also contain bleaching agents and activators, material care agents, and chelating agents such as disclosed in WO 98/03622, incorporated herein by reference. To exemplify an embodiment of the present invention and demonstrate its benefits, Formula B, an embodiment of the present invention having 3% boric acid, 0.5% propanediol and Duramyl, is compared with Formula A, having 3% boric acid, 0.5% propanediol and Termamyl, in Table 1. A comparison of the Duramyl amylase enzyme stability versus Termamyl enzyme stability is shown in Table 2. Table 1 Table 2 As can be seen above, Formula B containing Duramyl has significantly better amylase stability than Formula A containing Termanyl. Other compositions of the present invention are as follows: Table 3 Accordingly, having thus described the invention in detail, it will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is described in the specification.

Claims: What is claimed is: 1. An aqueous liquid or gel type detergent composition characterized in that it comprises: (a) from 0.1 % to 15% by weight, of boric acid or a boron compound capable of forming boric acid in the composition; (b) from 0.1% to 10% by weight, of a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, 1,2-propanediol, butylene glycol, hexylene glycol, glycerol, mannitol, sorbitol, erythritol, glucose, fructose, lactose, erythritol- 1 ,4-anhydride, and mixtures thereof; (c) an oxygen bleach resistant α-amylase enzyme; and (d) from 5% to 80% water. 2. The detergent composition according to claim 1, comprising from 0.5% to 10%, preferably from 1% to 5%, by weight of boric acid. 3. The detergent composition according to claim 1 or 2, wherein said polyhydroxy compound is 1,2-propanediol. 4. The detergent composition according to any one of the preceding claims, comprising from about 0.1% to about 7% by weight of said polyhydroxy compound. 5. The detergent composition according to any one of the preceding claims comprising by weight 0.1% to 2% of the oxygen bleach resistant α-amylase enzyme, and from 40% to 70% of water. 6. The detergent composition according to any one of the preceding claims further comprising from 0.1% to 2% of a protease enzyme. 7. A process for stabilizing an amylase enzyme in an aqueous enzymatic liquid or gel type detergent composition characterized in that it comprises mixing, with detergent ingredients: (i) from 0.1% to 15% by weight, of boric acid or a boron compound capable of forming boric acid in the composition; (ii) from 0.1 % to 10% by weight, of a polyhydroxy compound selected from the group consisting of ethylene glycol, propylene glycol, 1 ,2-propanediol, butylene glycol, hexylene glycol, glycerol, mannitol, sorbitol, erythritol, glucose, fructose, lactose, erythritol- 1 ,4-anhydride, and mixtures thereof; and (iii) an oxygen bleach resistant α-amylase enzyme. 8. A process according to claim 7 comprising, by weight of the composition, from 1% to 5% of boric acid, from 0.1% to 7% of the polyhydroxy compound, and from 0.1% to 2% of the oxygen bleach resistant α-amylase enzyme. 9. A process according to claim 7 or 8 comprising from 40% to 70% water, and wherein the polyhydroxy compound is 1,2-propanediol. 10. A process according to claim 7, 8 or 9 further comprising from 0.1% to 2% of a protease enzyme.

Inventors: LYNDE KENT, SONG BRIAN XIAOQING, LYNDE, KENT, SONG, BRIAN, XIAOQING
Applicants: LYNDE KENT, PROCTER & GAMBLE, SONG BRIAN XIAOQING, LYNDE, KENT, SONG, BRIAN, XIAOQING, THE PROCTER & GAMBLE COMPANY
Application year: 2000
Main classification: C11D3
IPC codes: C11D3, C11D7, C11D17