GB2287950A

GB2287950A - Detergent composition

Info

Publication number: GB2287950A
Application number: GB9406546A
Authority: GB
Inventors: Jonathan Richard Clare; Michael Alan John Moss; Christiaan Arthur Jacque Thoen
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1994-03-31
Filing date: 1994-03-31
Publication date: 1995-10-04
Also published as: WO1995027030A1; GB9406546D0; JPH09511271A; CA2184364A1; CN1174570A; EP0753044A4; EP0753044A1

Abstract

A detergent composition comprises a surfactant selected from anionic, nonionic, cationic, amphoteric and zwitteronic detergent-active compounds and mixtures thereof; a detergency builder comprising zeolite P having a silicon to aluminium ratio not greater than 1.33 (zeolite MAP); and a proteolytic enzyme having an isoelectric point below 10. Alcalase is exemplified. Preferably the composition is free of enzymes having an isoelectric point above 10.

Description

TITLE: DETERGENT COMPOSITION The present invention relates to a detergent composition and, in particular, to improvements in the detergency performance of laundry detergent compositions comprising zeolites as a sequestering agent for water hardness.

Detergent compositions for heavy-duty fabric washing conventionally contain detergency builders which lower the concentration of calcium and magnesium water hardness ions in the wash liquor and thereby provide good detergency effect in both hard and soft water.

Conventionally, inorganic phosphates, such as sodium tripolyphosphate, have been used as builders for laundry detergents. More recently, alkali metal aluminosilicate ion-exchangers, particularly crystalline sodium aluminosilicate zeolite A, have been proposed as replacements for the inorganic phosphates.

For example, EP 21 491A (Procter & Gamble) discloses detergent compositions containing a building system which includes zeolite A, X or P (B) or a mixture thereof. EP 384070A (Unilever) discloses specific zeolite P materials having an especially low silicon to aluminium ratio not greater than 1.33 (hereinafter referred to as zeolite MAP) and describes its use as a detergency builder. To date, however, zeolite A is the preferred aluminosilicate detergency builder in commercially available products.

EP 384070A (Unilever) suggests that zeolite MAP has advantages as a detergency builder over other zeolites. We have found, however, that detergent compositions comprising zeolite MAP as detergency builder, particularly those with little or no bleach, have a marked incompatibility with printed cotton fabrics as compared with conventional detergent compositions comprising other zeolites such as zeolite A. In particular, it has been found that detergent compositions containing zeolite MAP reduce the substantivity of printed pigment on a fabric surface, thereby shortening fabric lifetime, as compared with detergent compositions comprising zeolite A.

We have surprisingly found that these problems can be substantially overcome by incorporating in the detergent composition a less aggressive proteolytic enzyme than those conventionally employed.

Detergent compositions containing proteases are well-known in the art. By using a protease in a detergent, it is possible to hydrolyze the proteins, present in stains and soil on the clothes, to such a degree that they become readily soluble in water.

It is equally well recognised that the relative ability of each protease to meet various performance criteria is among others dependent on the composition of the detergent matrix. As a consequence, the detergent formulator is faced with a difficult task of providing detergent compositions containing a protease, wherein said protease has an excellent detergency performance.

The present invention is based on the unexpected finding that the fabric care profile of a detergent composition comprising zeolite MAP and containing a protease having an isoelectric point below 10 is superior to that of comparable compositions containing other proteases having an isoelectric point of higher than 10.

Examples of suitable proteases according to this invention having an isoelectric point below 10 include Alcalase (Trade Mark), Maxatase (Trade Mark), Optimase (Trade Mark) and Primase (Trade Mark).

Examples of proteases which have an isoelectric point of higher than 10 and which have been found not to afford such a superior fabric care profile are Savinase (Trade Mark), which is disclosed, in EP 384070A (Unilever) Opticlean (Trade Mark) Maxacal (Trade Mark), Purafect (Trade Mark), and Esperase (Trade Mark).

This finding allows the formulation of detergent compositions providing both excellent cleaning and fabric care properties on cotton and woollen fabrics.

Thus, the present invention provides a detergent composition comprising: a) a surfactant selected from anionic, nonionic, cationic, amphoteric and zwitterionic detergent - active compounds and mixtures thereof; b) a detergency builder comprising zeolite P having a silicon to aluminium ratio not greater than 1.33 (zeolite MAP); and c) a proteolytic enzyme having an isoelectric point below 10.

In a preferred embodiment of the invention, the detergent composition is free of any proteolytic enzyme which has an isoelectric point greater than 10.

The detergent composition according to the invention preferably does not contain a bleach.

According to another aspect of the invention, the composition does not contain an optical brightener.

The detergent composition according to the invention contains, as an essential ingredient, one or more surfactants selected from anionic, nonionic, cationic, amphoteric and zwitterionic detergent-active compounds and mixtures thereof. Such surfactants are well known and described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II by Schwartz, Perry and Berch.

Examples of suitable anionic surfactants include alkylbenzene sulphonates, particularly sodium linear alkylbenzene sulphonates having an alkyl chain length of C8-Cl5; C12-C15 primary alkyl sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates.

Sodium salts are generally preferred.

Examples of suitable nonionic surfactants include alkoxylated adducts of fatty alcohols containing an average of less than 5 alkylene oxide groups per molecule, for example less than 4 alkylene oxide groups per molecule e.g. 3.5 and usefully 3 alkylene oxide groups per molecule or less and usefully also greater than 0.5, or 1, or 2 alkylene oxide groups per molecule.

A particularly preferred aliphatic alcohol ethoxylate is a primary alcohol having an average of 12 to 15 carbon atoms in the alkyl chain condensed with an average of three ethoxy groups per mole of alcohol.

Specific examples of suitable alkoxylated adducts of fatty alcohols are Synperonic A3 (ex ICI), which is a C13-C15 alcohol with about three ethylene oxide groups per molecule and Empilan KB3 (ex Marchon), which is lauric alcohol 3EO.

Another class of nonionic surfactants comprises alkyl polyglucoside compounds of general formula RO (CnH2nO) tZx wherein Z is a moiety derived from glucose; R is a saturated hydrophobic alkyl group that contains from 12 to 18 carbon atoms; t is from 0 to 10 and n is 2 or 3t x is from 1.1 to 4, the compounds including less than 10% unreacted fatty alcohol and less than 50% short chain alkyl polyglucosides. Compounds of this type and their use in detergent compositions are disclosed in EP-B 0070074, 0070077, 0075996 and 0094118.

The surfactant will generally be included in the detergent composition in an amount of 5 to 60% by weight, preferably 5 to 40% by weight and most preferably from 10 to 25% by weight of the composition.

According to the present invention the detergency builder system is based on zeolite MAP, optionally in conjunction with one or more supplementary builders. The amount of zeolite MAP employed may range, for example, from 5 to 60 wt%, more preferably from 15 to 40 wt%.

Zeolite MAP is described in EP 384070A (Unilever). It is defined as an alkali metal alumino silicate of the zeolite P type having a silicon to aluminium ratio not greater than 1.33, preferably within the range from 0.9 to 1.33 and more preferably within the range of from 0.9 to 1.2.

Of particular interest is zeolite MAP having a silicon to aluminium ratio not greater than 1.15 and, more particularly, not greater than 1.07.

Zeolite P having a Si:Al ratio of 1.33 or less may be prepared by the following steps: (i) mixing together a sodium aluminate having a mole ratio Na2O:A12O3 within the range of from 1.4 to 2.0 and a sodium silicate having a mole ratio SiO2:Na2O within the range of from 0.8 to 3.4 with vigorous stirring at a temperature within the range of from 25"C to boiling point usually 95"C, to give a gel having the following composition; A12O3: (1.75-3.5) SiO2 : (2.3-7.5) Na2O :P (80-450)H20; (ii) ageing the gel composition for 0.5 to 10 hours, preferably 2 to 5 hours, at a temperature within the range of from 70"C to boiling point, usually to 95"C, with sufficient stirring to maintain any solids present in suspension; (iii) separating the crystalline sodium aluminosilicate thus formed, washing to a pH within the range of from 10 to 12.5, and drying, preferably at a temperature not exceeding 1500C, to a moisture content of not less than 5 wt%.

Preferred drying methods are spray-drying and flash drying. It appears that oven drying at too high a temperature may adversely affect the calcium binding capacity of the product under certain circumstances.

Commercial sodium metasilicate pentahydrate dissolved in water and commercial sodium silicate solution (waterglass) are both suitable silica sources for the production of zeolite P in accordance with the invention. The reactants may be added together in any order either rapidly or slowly. Rapid addition at ambient temperature, and slow addition at elevated temperature (90-95"C) both give the desired product.

Vigorous stirring of the gel during the addition of the reactants, and at least moderate stirring during the subsequent ageing step, however, appear to be essential for the formation of pure zeolite P. In the absence of stirring, various mixtures of crystalline and amorphous materials may be obtained.

Zeolite MAP generally has a calcium binding capacity of at least 150 mg CaO per g of anhydrous aluminosilicate, as measured by the standard method described in GB 1473201 (Henkel). The calcium binding capacity is normally 160 mg CaO/g and may be as high 170 mg CaO/g.

Although zeolite MAP like other zeolites contains water of hydration, for the purposes of the present invention amounts and percentages of zeolite are expressed in terms of the notional anhydrous material. The amount of water present in hydrated zeolite MAP at ambient temperature and humidity is generally about 20 wt%.

A preferred zeolite MAP for use according to the present invention has a d50 of from 1.0 to 5.0 micrometres, for example 2.25 to 5 micrometres, more particularly 2.75 to 5 micrometres.

According to one embodiment of the invention the zeolite MAP detergent builder is in powder form.

For convenience in handling, however, the material may be granulated by conventional techniques such as spray drying or by a non-tower method to form larger particles.

The detergent composition according to the present invention essentially comprises a proteolytic enzyme of isoelectric point below 10.

Unlike proteases having an isoelectric point higher than 10, it has been found that detergent compositions comprising zeolite MAP as detergency builder, when formulated with a protease having an isoelectric point below 10, do provide both excellent cleaning performance and fabric care performance on cotton and woollen fabrics.

Suitable proteases include proteases represented by the genus of Subtilisin Carlsberg, producible by Bacillus licheniformis. Other suitable proteases include the proteases represented by the genus Subtilisin BPN', producible by Bacillus amyloliquefaciens. Other suitable proteases are proteases which show a positive immunological crossreaction with the antibody of the proteases as described hereinabove. Highly preferred proteases are the proteases that are commercially sold under the tradenames Alcalase (Trade Mark), Maxatase (Trade Mark) Optimase (Trade Mark), Primase (Trade Mark) or mixtures thereof.

The proteases according to the present invention are present in an amount to provide from 1 to 20, preferably from 1 to 10, more preferably from 2 to 5 Anson units of active enzyme per 100 parts of the detergent composition.

In the granular detergent compositions according to the invention, the detergency builder can be zeolite MAP alone or a combination of zeolite MAP with an organic or inorganic cobuilder.

Suitable organic cobuilders can be monomeric or polymeric carboxylates such as citrates or polymers of acrylic, methacrylic and/or maleic acids in neutralised form. Suitable inorganic cobuilders include carbonates, and amorphous and crystalline lamellar sodium silicates.

Suitable silicates have the composition: NaMSixO2x+l 1 where M is sodium or hydrogen, preferably sodium; x is a number from 1.9 to 4; and y is a number from 0 to 20. Such materials are described in US Patents No. 4664839t No. 4728443 and No. 4820439 (Hoechst AG). Especially preferred are compounds in which x = 2 and y = O. The synthetic material is commercially available from Hoechst AG as S-Na2 Si205 (SXS6) and is described in US Patent No. 4664830.

The total amount of detergency builder in the granular composition ranges from 10 to 80 wt%, more preferably 10 to 45 wt%.

Other materials which may be present in the detergent compositions of the invention include, for example, fluorescers, antiredeposition agents, inorganic salts such as sodium sulphate, other enzymes, lather control agents, fabric softening agents, pigments, coloured speckles and perfumes.

The detergent compositions of the invention may be prepared by any suitable method. The particulate detergent compositions are suitably prepared by any tower (spray-drying) or non-tower process.

In processes based around a spray-drying tower, a base powder is first prepared by spray-drying a slurry then be sprayed on or admixed (post-dosed).

The proteolytic enzyme will generally be post-dosed.

The zeolite MAP is suitable for inclusion in the slurry, although it may be advantageous for processing reasons for part of the zeolite MAP to be incorporated post-tower. The lamellar silicate, where this is employed, is also preferably post-dosed.

Alternatively, particulate detergent compositions in accordance with the invention may be prepared by wholly non-tower processes such as granulation.

The granular detergent compositions of the invention may be prepared to any suitable bulk density.

The compositions preferably have a bulk density of at least 400 g/l preferably at least 550 g/l, most preferably at least 700 g/l and, with particular preference at least 800 g/l.

The benefits of the present invention are particularly evident in powders of high bulk density, for example, of 700 g/l or above. Such powders may be prepared either by post-tower densification of spraydried powder, or by wholly non-tower methods such as dry mixing and granulation; in both cases a high-speed mixer/granulator may advantageously be used. Processes using high-speed mixer/granulators are disclosed, for example, in EP340 013A, EP 367 339A, EP 390 251A and EP 420 317A (Unilever).

According to a further aspect of the invention there is provided a liquid detergent composition, preferably a heavy duty liquid detergent composition comprising a surfactant as previously described, a detergency builder comprising zeolite MAP and a proteolytic enzyme having an isoelectric point below 10.

According to this embodiment the liquid detergent composition may be of any convenient physical form which may be aqueous or anhydrous. The term "liquid" used herein includes pasty viscous formulations such as gels. The liquid detergent system comprises, as the detergency builder zeolite MAP optionally in combination with other detergency builders such as fatty acids, citric acid or zeolite A.

A preferred co-builder is a lamellar sodium silicate such as SKS-6 which is particularly useful in pasty viscous formulations such as gels or in nonaqueous liquid detergents such as those described in WO92/16608 (Henkel).

The liquid detergent composition generally has a pH of from 6.5 to 10.5.

The total amount of detergency builder in the liquid composition is preferably from 5 to 70% of the total liquid composition.

Preferred bleach free detergent compositions according to the invention are characterised by having a pH < 10.5, preferably < 10.4, most preferably < 10.3.

Highly preferred compositions of the invention also have a low level of reserve alkalinity. Reserve alkalinity is expressed as g of NaOH per 100 g of composition as determined by acid titration of a sample, as 1% solution in distilled water to a pH of 9.5. Preferred values of reserve alkalinity are < 3.0 g preferably < 2.0 g, most preferably < 1.5 g.

The invention is further illustrated by the following Example.

The following abbreviations have been used.

C24AS - sodium C24 alkylsulphate C25E4 - C12 - C15 primary aliphatic ethoxylated alcohol having an average of 7 ethoxy groups per mole of alcohol DETPMP - diethylene triamine penta (methylene phosphonic acid) CMC - carboxymethyl cellulose PVP - polyvinylpyrrolidone EXAMPLES Component Reference 1 Reference 2 Example (% by wt) (% by wt) (% by wt) C24AS 6.0 6.0 6.0 C25 E4 8.0 8.0 8.0 Zeolite A - 40.0 Zeolite MAP 40.0 - 40.0 Carbonate 7.0 7.0 7.0 Citrate 10.0 10.0 10.0 DETPMP 0.4 0.4 0.4 CMC 1.0 1.0 1.0 PVP 1.0 1.0 1.0 MA/AA** 4.0 4.0 4.0 citric acid 3.0 3.0 3.0 Savinase 2.0 2.0 Alcalase - - 2.0 Brightener* 0.2 0.2 0.2 Balance Moisture and Miscellaneous to 100 *Tinopal DMS ex Geigy **Sokolan CP5 M.wt 70,000 The detergent composition according to the invention which comprises Zeolite MAP and Alcalase shows good results in stain removal and low fabric damage as compared with a composition comprising Zeolite MAP with Savinase.

Claims

CLAIMS:

1. A detergent composition comprising: (a) a surfactant selected from anionic, nonionic, cationic, amphoteric and zwitterionic detergent - active compounds and mixtures thereof; (b) a detergency builder comprising zeolite P having a silicon to aluminium ratio not greater than 1.33 (zeolite MAP); and (c) a proteolytic enzyme having an isoelectric point below 10.

2. A detergent composition according to claim 1, which does not contain any proteolytic enzyme of isoelectric point > 10.

3. A detergent composition according to claim 1 or 2, which does not contain a bleach.

4. A detergent composition according to any of claims 1 to 3, which is substantially free of optical brighteners.

5. A detergent composition according to any one of claims 1 to 4, wherein the zeolite MAP has a silicon to aluminium ratio not greater than 1.15.

6. A detergent composition according to claim 5, wherein the zeolite MAP has a silicon to aluminium ratio not greater than 1.07.

7. A detergent composition according to any of claims 1 to 6, wherein the zeolite MAP has a particle size D50 of from 1 to 5 micrometres.

8. A detergent composition according to any one of claims 1 to 7, which comprises from 5 to 80% by weight of zeolite MAP.

9. A detergent composition according to any one of claims 1 to 8, which comprises the proteolytic enzyme in an amount to provide from 1 to 20 Anson units of active enzyme per 100 parts of the detergent composition.

10. A granular detergent composition according to any of claim 1 to 9, which comprises from 5 to 60 wt % of component (a); from 10 to 80 wt% of component (b) and a proteolytic enzyme (c) in an amount to provide from 1 to 20 Anson units of active enzyme per 100 parts of the detergent composition.

11. A liquid detergent composition according to any of claims 1 to 9 which comprises from 5 to 60 wtt of component (a); from 5 to 40 wt% of component (b); and a proteolytic enzyme (c) in an amount to provide from 1 to 20 Anson units of active enzyme per 100 parts of the detergent composition.

12. A detergent composition according to any one of claims 1 to 11, which comprises the proteolytic enzyme in an amount to provide from 2 to 5 Anson units of active enzyme per 100 parts of the composition.

13. A detergent composition according to any one of claims 1 to 12, wherein the enzyme having an isoelectric amount of below 10 is Alcalase.

14. A detergent composition according to any one of claims 1 to 13, wherein the composition has a reserve alkalinity (expressed as g of NaOH per 100 g of composition as determined by acid titration of a sample as 1% solution in distilled water to a pH of 9.5) of < 3.0 g.

15. A detergent composition according to claim 14, wherein the reserve alkalinity is < 1.5 g.