GB2288187A

GB2288187A - Detergent composition

Info

Publication number: GB2288187A
Application number: GB9406567A
Authority: GB
Inventors: Jonathan Richard Clare; Michael Alan John Moss; Christiaan Arthur Jacque Thoen; Michael Duncan; Thomas Wilhelm Hyrner
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1994-03-31
Filing date: 1994-03-31
Publication date: 1995-10-11
Also published as: EP0753042A1; WO1995027027A1; CA2184363A1; EP0753042A4; JPH09511269A; CN1168690A; GB9406567D0

Abstract

A detergent composition comprising a surfactant selected from anionic, nonionic, cationic, amphoteric and zwitterionic detergent-active compounds and mixtures thereof and a detergency builder comprising zeolite P having a silicon to aluminium ratio not greater than 1.33 (zeolite MAP) and having a particle size, d50, of from 2.25 to 5 micrometres, preferably 2.75 to 5 micrometres. The detergent composition is preferably free of bleach. Granular and liquid detergent compositions are preferred.

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 384,070A (Unilever) suggests that zeolite MAP has advantages as a detergency builder over other zeolites. The preferred zeolite MAP in accordance with the disclosure of EP 384070A has a d50 (as defined hereinafter) within the range of from 0.1 to 5.0 micrometres, preferably within the range of from 0.1 to 1.0 micrometres and more preferably within the range of from 0.4 to 0.7 micrometres. The quantity "d50t' indicates that 50% by weight of the particles have a diameter smaller than that figure.

We have found 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 using, as the detergency builder, a zeolite MAP having a particle size d50 somewhat larger than the preferred particle size ranges previously proposed.

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; and b) a detergency builder comprising zeolite P having a silicon to aluminium ratio not greater than 1.33 (zeolite MAP) and having a particle size, d50, of from 2.25 to 5 micrometres.

According to a preferred embodiment the zeolite MAP has a particle size d50 of from 2.75 to 5 micrometres.

Preferably the detergent composition according to the present invention contains no bleach.

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-C15; 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 3; 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 C.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:Al203 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 150"C, 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.%.

The zeolite MAP used in the present invention has a particle size d50 of from 2.25 to 5 micrometres, more particularly from 2.75 to 5 micrometres. The particle size is determined by conventional analytical techniques such as, for example, microscopic determination utilizing a scanning electron microscope or by means of a laser granulometer.

Zeolite MAP having the required particle size according to the present invention can be prepared by the conventional techniques as described above while adopting one or more of the following steps:a) increasing crystallisation temperature and reducing crystallisation time.

b) increasing the size of the seed crystals used to produce the zeolite; c) feeding the aluminosilicate gels into the crystallisation stage immediately after they form (i.e. eliminate ageing of gels); d) screening the zeolite product to remove fine material.

The detergent composition according to the invention generally contains zeolite MAP in an amount of 5 to 80% by weight of the composition, preferably 5 to 60% and most preferably 10 to 40% by weight of the composition.

According to the invention zeolite MAP may be the sole builder component or it may be used in combination with an organic or inorganic cobuilder.

According to a particular embodiment of the invention, zeolite MAP is the principal builder component.

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 , yH20 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. 4664839; 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 (SKS6) and is described in US Patent No. 4664830.

The total amount of detergency builder in the granular composition ranges from 5 to 80 wt%, more preferably from 15 to 60 wt% and most preferably from 10 to 45 wt%.

The detergent composition according to the invention may include the conventional detergent materials. However, preferably the composition is free of bleach. Other optional materials which may be present include, for example, enzymes, fluorescers, antiredeposition agents, inorganic salts such as sodium sulphate, lather control agents, fabric softening agents, pigments, coloured speckles and perfumes.

The detergent compositions of the invention may be of any physical type, for example, powders, liquids and gels. However, granular and liquid compositions are preferred.

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 and then other components unsuitable for processing via the slurry can be sprayed on or admixed (postdosed).

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.

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 one aspect of the invention there is provided a granular detergent composition comprising: a) from 5 to 60 wt%, preferably 5 to 40 wt%, of one or more surfactants selected from anionic, nonionic, cationic, amphoteric and zwitterionic detergent-active compounds and mixtures thereof, and b) from 10 to 80 wt% of a detergency builder comprising zeolite P having a silicon to aluminium ratio not greater than 1.33 (zeolite MAP) and having a particle size d50 of from 2.25 to 5 micrometres, preferably from 2.75 to 5 micrometres.

According to another embodiment of the invention there is provided a liquid detergent composition, preferably a heavy duty liquid detergent composition, comprising from 5 to 60 wt% of component (a) above and from 5 to 40 wt% of component (b) above.

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 partly viscous formulations such as gels. 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.

According to a further aspect, the invention provides use of zeolite MAP having a particle size d50 of 2.25 to 5 micrometres, preferably from 2.75 to 5 micrometres as an additive for a detergent composition.

The following Example provides an illustration of a detergent composition according to the present invention.

The following abbreviations have been used: AS : - sodium alkyl sulphate AE5 and AE45 : - tallow alcohol ethoxylated with 5 or 4 to 5 ethoxy groups per mole alcohol CMC : - sodium carboxymethyl cellulose EDTMP : - ethylene diamine tetramethylene phosphonate PVP :- polyvinyl pyrrolidone MA/AA copolymer :- copolymer of 1:4 maleic/acrylic acid, average molecular weight about 80,000 TAED : - tetracetyl ethylene diamine EXAMPLES 1. 2.

Component Proportion (bv wt) zeolite MAP (d50 = 3.0 micrometres) 40% 38.5% Carbonate 7% 7.2% Silicate 2.OR 5% 5.8% Citrate 15% C14-C15 AS 7% C12-C14 AS - 5.6% AE5 12% AE45 ~ 11.5% Citric Acid 3% 3.0% Silicone Antifoam 0.5% Soap - 1.0% Hyfac 1.0% Wax 0.5% MA/AA copolymer 1.5% 1.8% Savinase (2.0 KNPO) 2.0% 2.0% Lipolase (100,000 Lo/l 0.4% 0.2% CMC 0.8% Optical Brightener 0.2% PVP 1.0% EDTMP 0.8% 0.1% TAED - 2.5% Sodium Percarbonate - 14.0% Moisture & Miscellaneous balance balance 100% 100%

Claims

CLAIMS 1. A detergent composition comprising: a) a surfactant selected from anionic, nonionic, cationic, amphoteric and zwitterionic detergent-active compounds and mixtures thereof; and b) a detergency builder comprising zeolite P having a silicon to aluminium ratio not greater than 1.33 (zeolite MAP) and having a particle size, d50, of from 2.25 to 5 micrometres.
2. A detergent composition according to claim 1, wherein the zeolite MAP has a particle size, d50, of from 2.75 to 5 micrometres.
3. A detergent composition according to claim 1 or 2, which contains no bleach.
4. A detergent composition according to any one of claims 1 to 3, wherein the detergency builder (b) comprises the zeolite MAP.
5. A detergent composition according to any one of claims 1 to 3, wherein the detergency builder (b) comprises the zeolite MAP and a cobuilder selected from monomeric and polymeric carboxylates, polymers of acrylic, methacrylic and/or maleic acids in neutralised form, and carbonates.
6. A detergent composition according to any one of claims 1 to 5, which comprises 5 to 80 wt% of the zeolite MAP.
7. A detergent composition according to claim 6, which comprises from 10 to 40 wt% of the zeolite MAP.
8. A detergent composition as claimed in any one of claims 1 to 6, wherein the zeolite MAP has a silicon to aluminium ratio not greater than 1.07.
9. A granular detergent composition according to any of claims 1 to 8, comprising from 5 to 60 wt% of component (a) and from 10 to 80 wt% of the component (b).
10. A liquid detergent composition according to any one of claims 1 to 8, comprising from 5 to 60 wt% of component (a) and from 5 to 40 wt% of component (b).
11. Use of zeolite P having a silicon to aluminium ratio not greater than 1.33 and having a particle size, d501 of from 2.25 to 5 micrometres as an additive for a detergent composition.