AU7504894A

AU7504894A - Laundry detergent composition

Info

Publication number: AU7504894A
Application number: AU75048/94A
Authority: AU
Inventors: Paul Aspin; Duncan Cooper Halliwell; Andrew John Harrison
Original assignee: Cussons International Ltd
Current assignee: Cussons International Ltd
Priority date: 1993-08-27
Filing date: 1994-08-30
Publication date: 1995-03-21
Also published as: CN1133058A; WO1995006098A1; PL304790A1; GB9317803D0

Description

LAUNDRY DETERGENT COMPOSITION

The present invention relates to a laundry detergent composition intended particularly but not exclusively for domestic laundering operations.

One problem which may be encountered in laundry operations is that dye from one garment may become dissolved in the wash water and then deposit on one or more other garments causing discolourations thereof. The problem can be particularly acute if garments of a relatively dark or deep colour are washed together with light coloured (e.g. white) or mixed garments which can become significantly discoloured.

It is known that polyvinylpyrrolidone (PVP), when incorporated in a laundry detergent formulation, will act as a dye transfer inhibitor.

Thus, for example, O-A-9218598 proposes a composition having colour care properties and containing a polyvinylpyrrolidone polymer having a molecular weight of 5,000 to 1,000,000, more preferably from 5,000 to 50,000, most preferably from 8,000 to 15,000. In addition to a surface active agent, the composition also contains an alkaline cellulase. Furthermore, WO-A-9218597 discloses a laundry detergent composition containing polyvinylpyrrolidone having a molecular weight of 5,000 to 22,000. This formulation may also contain a cellulase.

We have now surprisingly found that the use, in a laundry detergent composition, of polyvinylpyrrolidone having a higher molecular weight than previously proposed for use in laundering operations leads to improved colour care performance.

Therefore according to the present invention there is provided a laundry detergent composition comprising at least one surface active agent and a polyvinylpyrrolidone having a molecular weight of greater than 1,000,000.

Molecular weight of polyvinylpyrrolidone as used in the invention is determined by SEC/LALLS (Size Exclusion Chromatography/Low Angle Laser Light Scattering) using the method disclosed in Journal of Liquid. Chromatography, 10(6), 1127-1150(1987) (Senak et al).

We have found that PVP having a weight average molecular weight greater than 1,000,000 is particularly effective for scavenging dye during washing and preventing its re-deposition on other garments in the same wash load.

Preferably the polyvinylpyrrolidone has a molecular weight of at least 1,200,000, more preferably at least 1,500,000. The molecular weight of the PVP may, for example, be 1,500,000 to 4,000,000. More preferably the molecular weight of the PVP may be in the range 2,000,000 to 4,000,000, e.g. 2,400,000 to 3,400,000. A particularly preferred molecular weight is about 2,900,000.

Examples of PVP which may be used include K-120 (molecular weight 2,540,000 to 3,220,000) and K-90 (molecular weight 1,270,000 to 1,710,000), both obtainable from ISP Europe.

Typically the PVP will be present in the formulation in an amount of 0.01 to 2.0% by weight (e.g. 0.05 to 2.0% by weight).

In addition to the PVP, the other essential ingredient of the formulation of the invention is a surface active agent. The surfactant used is preferably an anionic and/or non-ionic surfactant. It is however also possible to use zwitterionic or amphoteric surface active agents.

Preferred anionic surfactants are anionic surfactant acids. Examples include alkyl aryl sulphonic acids, fatty acid sulphonic acids, olefin sulphonic acids, fatty alcohol ether sulphuric acid, fatty methyl ester sulphonic acid, and alkane sulphonic acids. It is particularly preferred that the surfactant acid is an alkyl aryl sulphonic or sulphuric acid containing an alkyl group with 9-20 carbon atoms and a sulphonic or sulphuric acid ester group (included in the term alkyl is the alkyl portion of the aryl groups), or a fatty acid sulphuric acid obtained by sulphating alcohols with an 8-18 carbon atom chain. Especially useful are linear straight chain alkyl benzene sulphonic acids in which the average number of carbon atoms in the alkyl group is 11 to 13.

The amount of anionic surfactant is preferably in the range 1% to 40% (e.g. 5% to 40%) with values toward the lower end of this range being preferred. Thus the preferred amount of anionic surfactant is 1% to 30% by weight, more especially 5% to 25% by weight (e.g. 7 to 25% by weight).

It is preferred that a non-ionic surfactant is included in the formulation due to their good detergency properties. Preferred non- ionics are water-soluble alcohol ethoxylates of HLB lower than 13. Such non-ionics are preferably C₁₂-C_{ι a} linear primary alcohols with 3 to 30 moles of ethylene oxide per mole of alcohol.

The amount of non-ionic surfactant present is preferably 1% to 15% (e.g. 1% to 10%) by weight.

Mixtures of surfactants may be used.

It is highly preferred that the detergent composition also incorporates a cellulase. The function of the cellulase (in relation to garments containing cellulosic, e.g. cotton fibres, is to digest microfibrils which are generated on the fibres. This prevents pilling of the garment and reduces reflectance. We have found that there is synergy between the higher molecular weight PVP used in the invention (i.e. molecular weight greater than 1,000,000) and cellulase in reducing reflectance of the fabric caused by fibrils generated by normal wear of the garment.

Examples of cellulases which may be used are those exemplified in WO-A-9218598. Generally the amount of cellulase used will be in the range 0.05% to 4% (e.g. 1% to 4%) by weight of the composition.

The formulation will generally also include a builder usually in an amount of 15% to 50% by weight. The preferred builders are phosphates, particularly sodium tripolyphosphate and ortho- and pyro- phosphates. An alkaline material may also be included, e.g. in an amount 15% to 35%, to provide performance benefits in the laundering process. The preferred alkaline material is sodium carbonate.

Other components which may be present in the formulation, the typical amounts in which they may be present, and specific examples thereof are shown in the following table.

Component Amount Example

Filler 0-50% Sodium Sulphate

Anti-Redeposition Agent 0.5-5% Sodium Carboxymethyl Cellulose

Corrosion Inhibitor 0-5% Sodium Metasilicate

Sequestering Agent 0%-5% EDTA

Perfume <1%

Optical Brightener <1% It is preferred that the detergent formulation in accordance with the invention is in powder or granular form. A particularly suitable method of producing such a powder or granular formulation is as disclosed in EP-A-0 353 976 (Cussons)

To produce formulations in accordance with the invention using this procedure, particulate solids to be incorporated in the composition are blended in a fluidisation process and then the liquids are sprayed onto the blend. This results in agglomeration of particles to form granules of various particle sizes ranging from 2 mm to less than 75 microns.

Typically formulations in accordance with the invention will be used in amounts sufficient to give up to 100 mg of PVP per litre of wash liquor, more preferably less than 40 mg 1^" .

One specific formulation in accordance with the invention is as follows.

Sodium Tripolyphosphate 40.000%

Light Sodium Carbonate 25.000%

Sodium Sulphate 8.500%

Polyvinyl Pyrrolidone (K-120 ex ISP Europe) 0.500%

Anti-Redeposition Agent 2.500%

Nonionic (Alcohol Ethoxylate) 4.000%

OBA 0.075%

Sequestering Agent 0.500%

Alkyl Benzene Sulphonic Acid 14.000%

Cellulase 0.500%

Perfume and Other Incidental Ingredients 4.425%

The invention is illustrated by the following non-limiting Examples.

Example 1

Three detergent compositions were tested to evaluate their effectiveness in retarding dye staining of cotton fabrics. The compositions are detailed below. Composition A (Invention)

Sodium Tripolyphosphate 31% by weight

Sodium Carbonate 27% by weight

Sodium Sulphate 12.5%

Sodium Bicarbonate 13%

Sodium Carboxymethylcellulose 4%

Alkyl Benzene Sulphonic Acid 8%

Polyvinylpyrrolidone (K-120 ex ISP) 0.5%

Celluzyme 0.7T (ex Novo) 0.35%

Perfume, Antifoam, EDTA 1.65%

Ethoxylated Nonionic Surfactant

Composition B (Comparative)

As for composition A but replacing PVP K-120 by PVP HP50 available from BASF. Accordim* to the manufactures literature, HP50 has a molecular weight of 40,000.

Composition C (Comparative)

A commercially available detergent containing neither PVP nor a cellulase enzyme.

Procedure

The above formulations were tested to determine their effectiveness in preventing deposition of dye (Solophenyl Blue GL) on white cotton fabric (scoured and bleached). The procedure was effected by washing the fabric in the presence of the dye in accordance with the conditions set out below using a Jefferies Rotadyer. This procedure was used because a known amount of dye is used and the results are more reproducible than is the case of a dyed fabric which can release dye on washing and cross-stain other fabrics.

Amounts Used: Composition A 7g/litre

Composition B 7g/litre

Composition C lOg/litre

Fabric to liquor ratio 1:10

Test fabric: - 100% white cotton, scoured and bleach Water hardness - Tap water (30 ppm CaC0₃)

Wash duration - 1 hour in Jefferies Rotadyer plus rinsing and drying (via tumble dryer)

Wash temperature - 40 and 60°C Dye to PVP ratio 1:1 and 0.5:1

Results

Results were measured on an ICS/Texacon Micromatch MM2000 reflectometer using Cielab L and b values (i.e. lightness and blueness). The results are shown in Table 1.

TABLE 1

Detergent Wash Temp Dye/PVP L Value b Value Ratio

A 40°C 1:1 91.160 +0.096

B 40°C 1:1 90.354 -1.118

C 40°C 1:1 80.980 -11.716

A 40°C 0.5:1 92.352 +1.368

B 40°C 0.5:1 92.201 +1.119

C 40°C 0.5:1 85.964 -6.719

A 60°C 1:1 87.934 -4.148

B 60°C 1:1 86.390 -5.558

C 60°C 1:1 77.976 -14.413

A 60°C 0.5:1 91.051 -0.412

B 60°C 0.5:1 89.635 -1.046

C 60°C 0.5:1 83.150 -9.326

Notes

L Values:- The higher the L value, the whiter the fabric b Values: - The more negative the b values, the bluer the fabric

The results clearly show that compositions in accordance with the invention give rise to higher L values and lower b values than either of the comparative compositions. Therefore these results show that compositions in accordance with the invention, incorporating the higher molecular weight PVP, are more effective for preventing dye deposition than the comparative compositions, including those which incorporate a lower molecular weight PVP.

Example 2

Six detergent formulations were tested to determine the effectiveness of PVP having a molecular weight greater than 1,000,000 and cellulase in reducing reflectance of fabrics. The detergent formulations were as follows:

Formulation No.

1 2 3 4 5 6

Sodium Bicarbonate 30% 30% 30% 30% 30% 30%

Sodium 30% 30% 30% 30% 30% 30%

Tripolyphosphate

Dodecyl Benzene 10% 10% 10% 10% 10% 10%

Sulphonic Acid

Sodium Sulphate 30% 28.57% i 29.3% 29.3% 27.87% i 27.87%

Celluzyme 0.7T - 1.43% - - 1.43% 1.43%

PVP HP50 - - 0.7% - 0.7% -

PVP K-120 - - - 0.7% - 0.7%

The tests were carried out an black cotton fabric which had previously been washed in a detergent formulation containing neither PVP nor cellulase enzyme.

The L value for each fabric was determined (after the aforementioned 2 washes) using an ICS/Texacon Micromatch MM2000 reflectometer.

The fabrics were then washed 10 times using formulations 1-6. The washing was carried out in a Tergotometer at 40°C for 30 minutes using an agitator speed of 90 rpm. The amount of each detergent formulation used was 10 g l^{- 1} and the water had a hardness of 30 ppm CaC0₃.

After washing, the L value of each fabric was again determined. For each fabric the value of i- L was determined using the following formula kL where L₂ = L value of fabric after the 10 washes

L₁ = L value of fabric prior to the 10 washes. The results are shown in the Table 2.

Table 2 Formulation No. L

1 +0.916

2 +0.236

3 +0.116

4 +0.246

5 +0.276

6 -0.659

A positive value of ΛL indicates that the black fabric is becoming lighter, i.e. the large positive value of - L the greyer the fabric is becoming. Conversely a negative value of ^L indicates that the fabric is becoming darker. With the exception of formulation 6, the values of ^ L are positive showing that detergent formulations 1- 5 result in increasing greyness of the fabric. It was only for formulation 6 that a negative value of ΔL was obtained, showing that reflectance had been reduced.

These results clearly demonstrate the synergistic effect obtained by using a combination of PVP K-120 and Celluzy e 0.7T.

Claims

1. A laundry detergent composition comprising at least one surface active agent and a polyvinylpyrrolidone having a molecular weight of greater than 1,000,000.

2. A composition as claimed in claim 1 wherein the polyvinylpyrrolidone has a molecular weight of at least 1,200,000.

3. A composition as claimed in claim 2 wherein the polyvinylpyrrolidone has a molecular weight of at least 1,500,000.

4. A composition as claimed in claim 3 wherein the molecular weight of the polyvinylpyrrolidone is 1,500,000 to 4,000,000.

5. A composition as claimed in claim 4 wherein the polyvinylpyrrolidone has a molecular weight in the range 2,400,000 to 3,400,000.

6. A composition as claimed in any one of claims 1 to 5 wherein the polyvinylpyrrolidone is present in the formulation in an amount of 0.01% to 2.0% by weight.

7. A composition as claimed in any one of claims 1 to 6 wherein the surfactant comprises an anionic surfactant.

8. A composition as claimed in claim 7 wherein the anionic surfactant is an alkyl aryl sulphonic acid.

9. A composition as claimed in claim 8 wherein the anionic surfactant is a linear straight chain alkyl benzene sulphonic acid in which the average number of carbon atoms in the alkyl group is 11 to 13.

10. A composition as claimed in any one of claims 7 to 9 wherein the anionic surfactant is present in an amount of 1% to 40-6.

11. A composition as claimed in any one of claims 1 to 10 wherein the surface active agent comprises a non-ionic surfactant.

12. A composition as claimed in claim 11 wherein the non-ionic surfactant is a water-soluble alcohol ethoxylate of HLB lower than 13.

13. A composition as claimed in claim 11 or 12 wherein the non-ionic surfactant is present in an amount of 1% to 15% by weight.

14. A composition as claimed in any one of claims 1 to 13 containing a cellulase.

15. A composition as claimed in claim 11 wherein the cellulase is present in an amount of 0.05% to 4% by weight of the composition.

16. A composition as claimed in any one of claims 1 to 15 including a builder.

17. A composition as claimed in claim 16 wherein the builder is present in an amount of 15% to 50% by weight.

18. A composition as claimed in claim 16 or 17 wherein the builder is sodium tripolyphosphate.

19. A composition as claimed in any one of claims 1 to 18 containing an alkaline material.

20. A composition as claimed in claim 19 wherein the alkaline material is sodium carbonate.

21. A composition as claimed in any one of claims 1 to 20 in powdered or granular form.