LIQUID OR GEL DETERGENT WITH INCREASED SPECIFIC GRAVITY

Abstract: A method of increasing specific gravity of a liquid or gel type deteregent product having a pH less than about 10.5, while at the same time imparting transparency or translucency to said liquid or gel type detergent product, comprises: (a) providing a liquid or gel type detergent composition having no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) maintaining a potassium: sodium weight ratio greater than at least about 0.4:1; and (c) adding one or more of potassium salts, ammonium salts, or mixtures thereof, in an amount of at least 5% by weight of the detergent product.

Description: LIQUID OR GEL DETERGENT WITH INCREASED SPECIFIC GRAVITY TECHNICAL FIELD The present invention relates to liquid or gel type detergent compositions. More particularly, the invention relates to a method for increasing the specific gravity of a transparent or translucent liquid or gel type detergent product which has a pH less than about 10.5, preferably less than about 10.0, and a transparent or translucent a liquid or gel type detergent product having a pH less than about 10.5, preferably less than about 10, and comprising (a) one or more of potassium or ammonium salts and (b) one or more potassium sources to maintain certain potassium to sodium ratios in order to make the composition transparent or translucent while at the same time preferably not using any (i) potassium tripolyphosphate or (ii) mixed sodium and potassium tripolyphosphate, while maintaining the degree of transparency or transluscency. BACKGROUND OF THE INVENTION Improving the aesthetics of a low to moderate pH (less than about 10.5, preferably less than about 10, and more preferably less than about 9.0) liquid or gel type detergent product (for example, a liquid gel automatic dishwashing (ADW) or liqui-gel ADW product) is believed to be a important aspect of such a product. Consumers of liquid ADW products have a preference for liquid ADW products having transparent or translucent characteristics. A transparent or translucent product allows for suspension of colored prills into that product, which can further enhance the physical appearance of the product. The transparent product may be clear, or dyed, using dyes that do not cause significant staining or dyeing of plastics during the wash cycle in automatic dishwashing. Consumers also have a preference for liquid ADW products that are heavier, i.e., ones that have increased specific gravity. Typically, an increase in specific gravity from about 1.2 grams/ml to about 1.3 grams/ml is deemed to be a significant increase that is appreciated and liked by consumers. In the low- free water environment of a typical phosphate containing gel type ADW composition, it is a real challenge to obtain clear or translucent characteristics. This is primarily due to the relatively low solubility of commodity phosphate builders, such as tripolyphosphate (STPP), which has a solubility typically of about 14.5 grams per 100 cc of water at room temperature. Previous formulators wishing to obtain clear or translucent characteristics in a liquid or gel type ADW have been forced to use highly soluble potassium tripolyphosphate (KTPP), or alternatively, commercially available mixed sodium and potassium tripolyphosphates (commonly referred to as SKTPP) which have heretofore served a dual purpose of being a potassium source (for transparency/franslucency) and a phosphate source (for cleaning performance). The use of KTPP and SKTPP is generally considered undesirable for various reasons, one of them being the economics of manufacturing. Alternatively, the previous formulators have been forced to use very low levels of KTPPs or SKTPs, which detrimentally affects cleaning performance. Thus, a considerable effort has been directed in this field, to develop novel solutions for attaining transparency and or translucency in liqui-gel ADWs. For high pH detergent formulations, KOH is the usual potassium source, for not only increasing the specific gravity of the product but also for increasing the alkalinity. However for low pH formulations (less than 10 pH and preferably no more than about 9 pH), the use of KOH in large amounts as a potassium source is undesirable. There has been an effort directed towards increasing the specific gravity of liquid or gel detergent products. However, the main drawback is that the present methods employed for increasing specific gravity cause the liquid or gel formulation to lose its transparency, and consequently, this takes away from the product's aesthetic appeal. It has been desirable to have liqui-gel ADW products that have a specific gravity closer to a value of 1.3 grams/ml rather than 1.2 grams/ml from an aesthetics standpoint. It has been desirable to have a liqui-gel ADW product having transparency and/or translucency characteristics, but with using no more than 20% by weight, preferably no more than about 10% by weight, more preferably no more than about 5% by weight, and most preferably 0% by weight (i) potassium tripolyphosphate (KTPP) and (ii) commercially available mixed sodium and potassium tripolyphosphate (SKTPP), while at the same time still maintaining high phosphate levels so as to not detrimentally affect cleaning performance. The inventors of the present invention have discovered that the addition of potassium or ammonium salts in an amount of at least 5% by weight of the detergent composition, serves to increase the specific gravity such that it is aesthetically pleasing while providing, if potassium salts are selected, a potassium source for transluscency. The inventors of the present invention have also discovered that by maintaining a K:Na weight ratio greater than at least about 0.4:1, preferably at least about 0.5:1, K:Na, outstanding translucent characteristics can be imparted without having to use KTPP or SKTPP. Thus, high phosphate levels can be attained by the addition of sodium tripolyphosphate (STPP) alone, along with the addition of potassium salts for low to moderate alkalinity. The present invention is thus directed to overcome one or more of the problems as set forth before. SUMMARY OF THE INVENTION The invention meets the needs above by providing a method of increasing specific gravity of a liquid or gel type detergent product which has a pH less than about 10.5, preferably less than about 10.0, while at the same time imparting transparency or translucency to said liquid or gel type detergent product, and a transparent or translucent a liquid or gel type detergent product having a pH less than about 10.5, preferably less than about 10, and a specific gravity of at least about 1.2 grams/ml. In one aspect of the present invention, the method of increasing specific gravity of a liquid or gel type detergent product having a pH less than about 10.5, preferably less than about 10.0, while at the same time imparting transparency or translucency to said liquid or gel type detergent product, comprises the steps of: (a) providing a liquid or gel type detergent composition having no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) maintaining a potassium: sodium weight ratio greater than at least about 0.4: 1, preferably at least about 0.5: 1; and (c) adding one or more of potassium salts, ammonium salts, or mixtures thereof, in an amount of at least 5% by weight of the detergent product. In another aspect of the present invention, a transparent or translucent liquid or gel type detergent product having a specific gravity greater than about 1.2 grams/ml and a pH less than about 10.5, preferably less than about 10.0, comprises: (a) a liquid or gel type detergent composition, the composition having no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) a potassiuπusodium weight ratio greater than at least about 0.4: 1, preferably at least about 0.5:1; and (c) one or more of potassium salts, ammonium salts, or mixtures thereof, in an amount of at least 5% by weight of said detergent composition. DETAILED DESCRIPTION OF THE INVENTION In the preferred embodiment of the present invention, method of increasing specific gravity of a liquid or gel type detergent product having a pH less than about 10.5, preferably less than about 10.0, while at the same time imparting transparency or translucency to said liquid or gel type detergent product, comprises: (a) providing a liquid or gel type detergent product having no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) maintaining a potassium:sodium weight ratio greater than at least about 0.4: 1, preferably at least about 0.5:1; and (c) adding one or more of potassium salts, ammonium salts, or mixtures thereof, in an amount of at least 5% by weight of the detergent product. The above processing steps may be performed in any order, or simultaneously, to provide the process and detergent product of the present invention. Limitation of or Express exclusion of KTPP and SKTPP In the preferred embodiment, the liquid or gel type detergent composition desirably contains no more than 20%, preferably no more than about 10%, more preferably no more than about 5%, and most preferably no more than 0%, by weight, of KTPP and SKTPP. The abbreviation KTPP as used herein means potassium tripolyphosphate, as is commercially available, which may contain incidental and/or trace impurities of other tripolyphosphates, such as STPP. The abbreviation SKTPP, as used herein means commercially available mixed sodium and potassium tripolyphosphates (SKTPP) wherein the weight ratio of Na:K is more than 95:5. Potassium or Ammonium Salts The process further includes the step of adding one or more of potassium salts or ammonium salts to the liquid or gel type detergent product, with any potassium sources providing no more than 20%, preferably no more than 10%, more preferably no more than 5%, and most preferably no more than 0% by weight potassium tripolyphosphate and mixed sodium and potassium tripolyphosphate. The preferred potassium salts herein are selected from the group consisting of K 2 SO 4 , KNO 3 , K 2 CO 3 , KC1, KBr, K 3 PO 4 , potassium silicate, potassium acetate, and mixtures thereof. When the potassium salt is selected from the aforementioned group, it is added in an amount desirably in a range of from about 2% to about 20% by weight of the detergent composition, and preferably in a range of from about 5% to about 16% by weight of the detergent composition, depending upon the availability of K in the potassium source on a molar basis. In the preferred embodiment of the present invention, the potassium source is potassium sulphate, which is preferably formed in situ in the composition by adding KOH and sulphuric acid. The amount of potassium sulphate is maintained in an amount desirably in a range of from about 5% to about 20% by weight of the detergent composition and preferably in a range of from about 8% to about 15% by weight of the detergent composition. The liquid or gel type detergent composition has a pH desirably less than about 10, preferably less than about pH 9.5, more preferably less than about pH 9.0. The term pH as used herein means pH of a 1% solution of the liquid or gel composition in water, by weight. When the potassium source is selected from the aforementioned group, the liquid or gel type detergent composition has a pH of at least about 6.5. The lower pH values are preferred when formulating the detergent composition with enzymes, which may be present in the composition in a liquid form or in the form of solid prills that are coated with a permeable or impermeable coating. K:Na weight ratio The process further includes the step of maintaining a potassium:sodium weight ratio greater than about 0.4: 1, preferably greater than about 0.45: 1, more preferably greater than about 0.5: 1, and most preferably above 0.65: 1. In a more preferred embodiment, the K:Na weight ratio is desirably maintained in a range of from about 0.5: 1 to about 1.25: 1, particularly when the detergent composition has a total solids content of less than about 20% by weight. Preferably, the potassium:sodium weight ratio is maintained at least greater than 0.75: 1, and more preferably, in a range of from about 0.75: 1 to about 2: 1 , potassium: sodium, particularly when the liquid or gel type detergent composition has a total solids content in a range of from about 20% to about 40% by weight. The total solids content comprises solids in the form of STPP, i.e., the phosphate builder, which is typically present in an amount in a range of about 10% to 40%, thickener, such as a polymer, and potassium hydroxide, i.e., one of the potassium sources. It should be noted that other optional ingredients may also make up the total solids content in a composition of the present invention. The compositions of the present invention preferably contain from about 20% to about 80%, more preferably from about 40% to about 70%, by weight of water. Specific Gravity In the preferred embodiment, the specific gravity of the detergent product is at least 1.23g/ml, preferably at least 1.25g/ml, and most preferably, greater than 1.28g/ml. In one embodiment, the specific gravity of the detergent product is at least 1.25g/ml, the product is transluscent, and the pH is less than about 9.5, preferably less than about 9.0. Phosphate Builder The liquid or gel type detergent composition provided in this process, preferably includes a phosphate builder in an amount desirably in a range of from about 10% to about 40% of said detergent composition, and preferably in a range of from about 12% to about 30% of said detergent composition. The preferred phosphate builder useful in practicing this invention is sodium tripolyphosphate (STPP). The STPP is essentially free of any KTPP, other than what may be present in trace quantities as naturally occurring impurity or an impurity during the commercial manufacturing of STPP. Other phosphate builders known to those skilled in the art may also be utilized in lieu of or in conjunction with STPP. These and other non-phosphate builders useful in the present invention are disclosed in WO 98/03622, published January 29, 1998, incorporated herein by reference. 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 or gel product may be improved, and the thickness of the product may be altered, by the addition of a cross-linking thickener to the liquid or gel 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) 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, (c) Enzymes In one aspect of the present invention, the liquid or gel detergent composition also contains an amylase enzyme. Amylases suitable herein, especially for but not limited to automatic dishwashing purposes, include for example α-amylases described in GB 1,296,839 to Novo, and especially TERMAMYL ® , available from Novo. FUNGAMYL ® from Novo is also useful herein. Engineering of enzymes for improved stability, e.g., oxidative stability, is known. See, for example, J. Biological Chem., Vol. 260, No. 1 1, June 1985, pp 6518-6521. Preferred amylases include those according to the WO 9402597, Novo, Feb. 3, 1994, incorporated herein by reference. Other amylases include variants having additional modification as described in WO 9510603 A, incorporated herein by referernce, 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. The compositions of the present invention also preferably contain protease enzymes to enhance cleaning performance. The enzyme stabilizing system herein is particularly effective at stabilizing amylases in the presence of proteases which are known to degrade enzymes. The preparation of protease enzyme and analogous enzymes is described in GB 1,243,784 to Novo. Other suitable proteases include ALCALASE ® and SAVINASE ® from Novo, as well as Protease A as disclosed in EP 130,756 A, January 9, 1985 and Protease B as disclosed in EP 303,761 A, April 28, 1987 and EP 130,756 A, January 9, 1985. See also a high pH protease from Bacillus sp. NCIMB 40338 described in WO 9318140 A to Novo. Enzymatic detergents comprising protease, one or more other enzymes, and a reversible protease inhibitor are described in WO 9203529 A to Novo. Other preferred proteases include those of WO 9510591 A to Procter & Gamble. When desired, a protease having decreased adsorption and increased hydrolysis is available as described in WO 9507791 to Procter & Gamble. A recombinant trypsin-like protease for detergents suitable herein is described in WO 9425583 to Novo. Enzymes are normally incorporated into detergent or detergent additive compositions at levels sufficient to provide a "cleaning-effective amount". The term "cleaning effective amount" refers to any amount capable of producing a cleaning, stain removal, soil removal, whitening, deodorizing, or freshness improving effect on substrates such as dishware and the like. In practical terms for current commercial preparations, the compositions herein may comprise from about 0.01% to about 5%, preferably about 0.1% to about 2% by weight of a commercial enzyme preparation. Protease enzymes are present in such commercial preparations at levels sufficient to provide from 0.005 to 0.1 Anson units (AU) of activity per gram of composition, (d) Other adjunct 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 U.S. Patent 4,537,707, Severson, and U.S. Patent 4,318,818, Letton, et. al., both 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 and Formula C, embodiments of the present invention having 10% and 7% by weight potassium sulphate, are compared with Formula A, which has 0% potassium sulphate, in Table 1. A comparison of the Specific Gravity and translucency is shown in Table 2. The pH of all formulas is less than about 10.0, with Formula C having a pH of about 9.6. Table 1 *3.4% active Table 2 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. A process of increasing specific gravity of a liquid or gel type detergent product having a pH less than 10.5, while at the same time imparting transparency or translucency to said liquid or gel type detergent product, characterized in that it comprises: (a) providing a liquid or gel type detergent product having no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) maintaining a potassium: sodium weight ratio greater than at least 0.4: 1 ; and (c) adding one or more of potassium salts, ammonium salts, or mixtures thereof, in an amount of at least 5% by weight of said detergent product. 2. The process according to claim 1 , wherein the detergent product has no greater than 5% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate. 3. The process according to claim 1 or 2, wherein the detergent product comprises a potassium salt selected from the group consisting of K SO 4 , KNO , K 2 CO 3 , KCl, KBr, K 3 PO 4 , potassium silicate, potassium acetate, and mixtures thereof. 4. The process according to any one of the preceding claims, wherein the detergent product comprises a potassium salt formed in situ by adding KOH and sulphuric acid to form K 2 SO , and said K 2 SO 4 is present in an amount of at least 5% by weight. 5. The process according to any one of the preceding claims, wherein said detergent product comprises a phosphate builder in an amount of from 10% to 40% of said detergent product. 6. The process according to any one of the preceding claims, wherein said detergent product has a total solids content of from 20% to 40% by weight. 7. A transparent or translucent liquid or gel type detergent product having a specific gravity greater than 1.2 grams/ml and a pH less than 10.5, characterized in that it comprises: (a) no greater than 20% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate; (b) a potassiuπusodium weight ratio greater than at least about 0.4: 1 ; and (c) one or more of potassium salts, ammonium salts or mixtures thereof, in an amount of at least 5% by weight of said detergent product. 8. The product according to claim 7, having no greater than 5% by weight of (i) potassium tripolyphosphate and (ii) mixed sodium and potassium tripolyphosphate. 9. The product according to claim 7 or 8, comprising a potassium salt selected from the group consisting of K 2 SO 4 , KNO , K CO 3 , KCl, KBr, K 3 PO 4 , potassium silicate, potassium acetate, and mixtures thereof. 10. The product according to claim 7, 8 or 9, comprising a potassium salt formed in situ by adding KOH and sulphuric acid to form K 2 SO 4 . 11. The product according to claim 7, 8, 9 or 10, wherein said detergent product has a total solids content of from 20% to 40% by weight. 12. The product according to any one of the preceding claims, wherein the specific gravity is at least 1.23g/ml, preferably at least 1.25g/ml.

Inventors: SONG BRIAN XIAOQING, SONG, BRIAN, XIAOQING
Applicants: PROCTER & GAMBLE, SONG BRIAN XIAOQING, SONG, BRIAN, XIAOQING, THE PROCTER & GAMBLE COMPANY
Application year: 2000
Main classification: C11D17
IPC codes: C11D3, C11D11, C11D17