EP2283107A1

EP2283107A1 - Process for treatment of a fabric

Info

Publication number: EP2283107A1
Application number: EP09761642A
Authority: EP
Inventors: Prasun Bandyopadhyay; Sayan Bandyopadhyay
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2008-06-10
Filing date: 2009-06-03
Publication date: 2011-02-16
Also published as: MX2010012824A; BRPI0907667A2; WO2009150079A1; CN102057029A; EA201001880A1; CL2010001396A1

Abstract

The present invention provides a process for treatment of a fabric comprising the steps of contacting the fabric with a cross-linked polycarboxylic polymer and a surfactant in presence of an aqueous medium having pH less than 5, and drying the fabric, and where the fabric is not rinsed with water between these steps. Moreover the invention provides a composition for treatment of a fabric comprising a cross-linked polycarboxylic acid and a surfactant, as well as a kit for treatment of a fabric comprising said fabric treatment composition comprising a cross-linked polycarboxylic acid and a surfactant, and a set of instructions.

Description

PROCESS FOR TREATMENT OF A FABRIC

Technical Field

The present invention relates to a process for treatment of a fabric. It further relates to a composition and a kit for treatment of a fabric.

Background and Prior Art

Various industrial treatments for fabric modification are known to render the fabric less prone to soiling. The fabric modification of this type is normally carried out during textile manufacture and such industrial treatments are relatively difficult to practise in household as they involve use of corrosive/unsafe chemicals and/or hazardous process conditions .

On the other hand, fabric cleaning compositions comprising surfactant and polymer are known, which are typically contacted with fabric followed by rinsing of fabric in water. However, conventional cleaning processes and compositions do not provide benefit of reduction in subsequent soiling of fabric. Rinse conditioners that are used at the stage of rinsing of fabrics comprise cationic surfactant and do not provide benefit of reduction in subsequent soiling of fabric.

US-5,004,557 relates to a clear or translucent liquid detergent composition that is pourable at room temperature and provides soil anti-redeposition, improved cleaning performance, and viscosity control, comprises 1 to 60% of at least one surfactant, up to 20% of a water-soluble sequester builder, 0.1 to 2% of an active agent selected from homopolymers and copolymers of acrylic acid, and enough water and other additives to make 100% of said composition. However, the soil redeposition of the compositions of US-5,004,557 leaves to be desired.

In view of the shortcomings of the prior art, one of the objects of the present invention is to provide a process for reducing soiling of fabrics that can be easily used in the household.

Yet another object of the present invention is to provide a process for treatment of a fabric that improves efficacy of subsequent cleaning.

Yet another object of the present invention is to provide a process for treatment of a fabric which is effective on various types of fabrics such as cotton, polyester and polycotton.

The present inventors have surprisingly found that contacting a fabric in an aqueous medium with a cross-linked polycarboxylic acid and a surfactant provides benefits such as reduction in soiling, ease of subsequent cleaning whilst being relatively easy to practice in household.

Summary of the invention

According to the present invention, there is provided a process for treatment of a fabric comprising the steps of:

(a) contacting the fabric with a cross-linked polycarboxylic acid and a surfactant in presence of an aqueous medium having pH less than 5, and;

(b) drying the fabric, where the fabric is not rinsed with water between the steps (a) and (b) . Detailed description of the invention

Fabric

The fabric that can be treated includes synthetic as well as natural textiles. Fabrics may be made of cotton, polycotton, polyester, silk or nylon. It is envisaged that the method of the present invention can be used to treat garments and other clothing and apparel materials that form typical washload in household laundry. The household materials that can be treated according to the process of the present invention include, but are not limited to, bedspreads, blankets, carpets, curtains and upholstery. Although the process of the present invention is described primarily for treatment of a fabric, it is envisaged that the process of the present invention can be advantageously used to treat other materials such as jute, leather, denim and canvass. It is envisaged that the process of the present invention can be used to treat articles such as shoes, rainwear and jackets.

Cross-linked polycarboxylic polymer The fabric is treated with a cross-linked polycarboxylic polymer and a surfactant in an aqueous medium having pH less than 5. The polycarboxylic polymer should be one that is interpolymerized with a multi-vinyl or multi-allylic functionalized cross-linking agent. Preferably, the polycarboxylic polymer is interpolymerized with a polyalkenyl polyether of a polyhydric compound. The polyhydric compound should have at least 4 carbons and 3 hydroxy groups. More specifically the polymer is a water dispersible copolymer of an alpha-beta monoolefinically unsaturated lower aliphatic carboxylic acid cross-linked with a polyether of a polyol. The polyol may be selected from the group consisting of oligosaccharides, reduced derivatives thereof in which the carbonyl group is converted to an alcohol group, and pentaerythritol . The hydroxy groups of said polyol are etherified with allyl groups, said polyol having at least two allyl groups per polyol molecule. A suitable copolymer is one of acrylic acid with low percentages (0.71 to 1.5%) of poly ally sucrose.

Molecular weights of the cross-linked polymer may range from about 500,000 up to 10,000,000 preferably between 500,000, and 2,000,000, optimally about 1,250,000. Examples of commercially available cross-linked polymers based upon allyl sucrose modified polyacrylic acid are the Carbopol® resins manufactured by the B. F. Goodrich Chemical Company. These materials include Carbopol 941® (molecular weight 1,250,000), Carbopol 934® (molecular weight 3,000,000) and Carbopol 940® (molecular weight 4,000,000) . Most preferred is Carbopol 980®.

The amount of cross-linked polycarboxylic polymer contacted per cm² area of the fabric is preferably from 0.1 to 200 mg, more preferably 1 to 100 mg, and most preferably 1 to 50 mg. It is particularly preferred that the amount of the polymer contacted per cm² area of the fabric is from 1 to 15 mg. The term "area of fabric" as used herein refers to surface area of one side of the fabric.

Surfactant

The fabric is treated with a cross-linked polycarboxylic polymer and a surfactant in an aqueous medium having pH less than 5. Any anionic, nonionic, zwitterionic or amphoteric surfactant or mixtures thereof can be used according to the present invention. Examples of anionic, nonionic, zwitterionic or amphoteric surfactants that can be used according to the present invention are given in ^λSurfactants and Interfacial Phenomena' by Milton J. Rosen, (Second edition, John Wiley & Sons, 1989), which is incorporated herein by reference.

The surfactant is preferably anionic, nonionic or mixture thereof. Nonionic surfactant is particularly preferred. The nonionic surfactant is preferably an alcohol ethoxylate having from 1 to 30 ethylene oxide groups. More preferably, the nonionic surfactant is a mixture of two alcohol ethoxylates, one having from 1 to 5 ethylene oxide groups and the other having from 6 to 10 ethylene oxide groups. Present inventors have determined that cationic surfactant, if used in the process of fabric treatment, leaves fabric more prone to subsequent soiling. Therefore, cationic surfactant, if present, should not be greater than preferably 100 ppm, more preferably 50 ppm, and most preferably 25 ppm of the aqueous medium. It is particularly preferred that the fabric is not contacted with cationic surfactant during the process of the present invention .

The amount of surfactant contacted per cm² area of the fabric is preferably from 0.1 to 200 mg, more preferably 1 to 100 mg, and most preferably 1 to 50 mg. It is particularly preferred that the amount of surfactant contacted per cm² area of the fabric is from 1 to 15 mg.

Aqueous medium

According to the invention, the fabric is contacted with the cross-linked polycarboxylic acid and the surfactant in presence of an aqueous medium having pH less than 5, more preferably less than 4, and most preferably less than 3.5. It is preferred that the pH of the aqueous medium is at least 1. If required, pH of the aqueous medium can be adjusted by adding acidic or alkaline agents, and/or buffering media. In particular, pH may be adjusted by adding acidic agents.

The aqueous medium may comprise either the cross-linked polycarboxylic acid, or the surfactant, or preferably both the cross-linked polycarboxylic acid and the surfactant. Alternatively, the cross-linked polycarboxylic acid, or the surfactant or both may be added to the aqueous medium during the process of the present invention.

The cross-linked polycarboxylic acid, when mixed with the aqueous medium, is from 0.005 to 10%, more preferably from 0.05 to 5%, and most preferably from 0.05 to 2% by weight of the aqueous medium.

The surfactant, when mixed with the aqueous medium, is from 0.005 to 10%, more preferably from 0.01 to 5%, and most preferably from 0.01 to 2% by weight of the aqueous medium. The aqueous medium preferably comprises a benefit agent. The benefit agent that can be included in the aqueous medium includes, but is not limited to ingredients such as perfume, fluorescer, deodorant, antibacterial agent, shading dye and bluing agent. One of the advantages of the present invention is that the deposition of benefit agent is enhanced. The aqueous medium may also contain detergent ingredients like builders, oxidative or reductive bleaches and bleach promoters.

The mass ratio of aqueous medium to fabric, or liquor to cloth ratio is preferably from 2 to 150, more preferably from about 5 to 100 and most preferably from 5 to 25. The step ( a )

The step (a) of contacting the fabric with the crosslinked polycarboxylic polymer and the surfactant in presence of an aqueous medium having pH less than 5 can be carried out in any suitable manner.

It is envisaged that the fabric is contacted with the crosslinked polycarboxylic polymer and the surfactant sequentially in any order, or simultaneously. Accordingly the fabric may be contacted with the surfactant, followed by contacting with the polymer. Alternatively the fabric may be contacted with the polymer, followed by contacting with the surfactant. However, it is preferred that the fabric is simultaneously contacted with both the polymer and the surfactant in presence of an aqueous medium having pH less than 5. In case of the sequential contacting, it is preferred that both the surfactant and the crosslinked polycarboxylic polymer are individually mixed with the aqueous medium prior to contacting with the fabric. In case of the simultaneous contacting, it is preferred that both the surfactant and the crosslinked polycarboxylic polymer are mixed with the aqueous medium prior to contacting with the fabric.

The crosslinked polycarboxylic polymer or the surfactant or both are mixed with the aqueous medium prior to contacting with the fabric.

The fabric may be dipped into the aqueous medium comprising the polymer and/or the surfactant. Alternatively, the aqueous medium comprising the polymer and/or the surfactant may be sprayed on the fabric. The step (b)

After the step (a) , the fabric is dried. When the step (a) involves immersion of fabric in the aqueous medium comprising the surfactant and the polymer, the fabric is removed from the aqueous medium before drying. The fabric may be subjected to wringing to remove part of the aqueous medium so that drying is faster .

Fabric may be dried by spreading the fabric on clothe line.

It is essential that the fabric is not rinsed with water between the steps (a) and (b) .

The step (c) After drying, the treated fabric is ready to use. Treated garments may be worn by user before subsequent washes. It is envisaged that the treated fabric will be less prone to subsequent soiling during use.

According to a preferred aspect, the process comprises a further step of washing the treated fabric with a cleaning medium comprising water and having pH preferably greater than 5, more preferably greater than 7, and most preferably greater than 8. The pH of cleaning medium is preferably from 5 to 14, more preferably from 7 to 12 and most preferably from 8 to 11.

The cleaning medium comprises water. Preferably, the cleaning medium further comprises an alkaline substance capable of raising the pH of the cleaning medium preferably above 8, more preferably above 9, and most preferably above 10. Accordingly, the cleaning medium preferably comprises hydroxide, carbonate, bicarbonate, phosphate, silicate or aluminate of an alkali metal or ammonium. It is particularly preferred that cleaning medium further comprises a surfactant. The cleaning medium may further comprise a builder.

Composition for treatment of a fabric

According to another aspect of the invention, there is provided a composition for treatment of a fabric comprising a cross- linked polycarboxylic acid and a surfactant.

The composition comprises preferably 0.1 to 99%, more preferably 10-90% and most preferably 20-80% by weight a crosslinked polycarboxylic polymer. The composition comprises preferably 0.1 to 99%, more preferably 10-90% and most preferably 20-80% by weight surfactant .

Preferably, the composition when added to water has pH less than 5, more preferably less than 4, and most preferably less than 3.5. Accordingly the composition may further comprise an acidic agent. The acidic agent is preferably from 0.1 to 10% of the composition.

Kit for treatment of a fabric According to another aspect of the present invention, there is provided a kit for treatment of a fabric comprising

(a) a fabric treatment composition comprising a cross-linked polycarboxylic acid and a surfactant, and;

(b) a set of instructions for use that instruct the user to add 0.1 to 1 parts of said fabric treatment composition to 500 to 1000 parts water to prepare a liquid, to immerse the fabric in said liquid, to remove the fabric from the liquid and to dry the fabric to obtain the treated fabric, without rinsing in water.

The kit may comprise a fabric treatment composition as described earlier.

Examples

The invention will now be demonstrated with examples. The examples are by way of illustration only and do not limit the scope of the invention in any manner.

Materials and methods

Following materials were used in the examples.

Table 1: Materials used in the examples

Fabrics

Fabric swatches of size 10 cm x 10 cm, weighing about 1 g were used. All the reflectance measurement results are based on average 5 swatches.

Desizing Protocol:

Fabrics were desized by soaking them overnight in a 3:1 mixture of chloroform and methanol, followed by two hot water washes in 3 g/L of commercially available detergent powder SURF EXCEL® in a washing machine maintaining liquor to cloth ratio of about 20.

Process of treating fabric Various polymers and surfactants and surfactant mixtures were used in the experiments as per the details given in the experiments. Following procedure was followed in all the experiments. An aqueous solution of the polymer was prepared prior to contacting with the fabric. To this solution the surfactant (or mixture of surfactants) was added followed by stirring. The pH of the aqueous medium was adjusted at various values from 3 to 6 by using pH lowering agent at various concentrations, in some cases using adequate amount of citric acid and sodium hydroxide as pH lowering and pH increasing agents respectively. The fabric was soaked in the aqueous solution, removed from the solution and air dried. In some experiments the fabric was first soaked in an aqueous solution of the polymer followed by soaking in an aqueous solution of the surfactant mixture, followed by air drying of the fabric. S o i l ing

Composite soil: Composite soil was prepared by mixing 5OmL of Triolein and 4 mg each of C-soot and Fe3θ4. It was then sonicated in an ultrasonic bath for two and a half hours.

300 μL of this composite soil was pipetted onto the fabric. This resulted into a stain of about 3 cm diameter on the fabric. The stain was allowed to dry before the soiled fabric was used for subsequent washing experiment.

Carbon soot: Dried fabric was soiled by dipping a fabric swatch in 3 mL carbon soot dispersion (150 ppm) in water in a petri- dish. The dispersion was stabilized by addition of sodium alkylbenzene sulfonate (50 ppm) . The fabric was then removed, dried and its reflectance was measured. Reflectance of fabric after soiling with carbon soot soil was used as a measure of stain-resistance of fabric, with lower value of AS (after soiling) reflectance indicating less stain-resistance

Washing

Dried fabric was loaded with different types of soil like carbon soot and composite soil. The fabric was then redried. The redried fabric was cleaned in a tergotometer with a cleaning medium. Fabrics were soaked in cleaning medium for 30 min maintaining liquor to cloth ratio of about 50. After soaking, the fabrics were washed in a tergotometer operating at rpm of about 90, for 15 minutes followed by 3 rinses of 2 minutes each.

Water was used as cleaning medium unless specified otherwise. In some experiments the cleaning medium further comprised sodium carbonate (0.05% by weight), sodium tripolyphosphate (0.05 % by weight), sodium silicate or commercially available detergent (SURF EXCEL® 0.3% by weight) . Higher values of reflectance are indicative of better cleaning.

Instruments:

Reflectometer- Gretag Macbeth Colour Eye 7000A was used for measurement of reflectance. Initial reflectance of fabric before treatment was measured. Reflectance was also measured after soiling (AS) and after washing the soiled fabric (AW) .

Experiments

In all the experiments, 6 cotton fabrics ( 10cm X 10cm) were immersed in 30 mL of aqueous medium comprising 0.1 g/L of CARBOPOL® 980 and 0.2 g/L of EO3 (Polyoxyethylene (3) lauryl ether]) or 0.2 g/1 EO7 (Polyoxyethylene (7) lauryl ether) or a mixture of both in step (a) unless indicated otherwise. At 0.5 g/L concentration of CARBOPOL®, the amount of polymer per cm² of fabric was about 15 mg whilst the amount of surfactant per cm² of fabric was about 6 mg when used at a concentration of 0.2 g/L. pH of the aqueous medium was measured and found to be about 4 .In some experiments, pH was changed to values of 8 and 10 by adding sodium hydroxide dropwise. In one of the experiment, pH was lowered by adding citric acid dropwise till pH reached value of 3. There was no step of rinsing after the step (a) unless mentioned otherwise. The fabrics were then air dried (step (b) ) . The dried fabrics were then soiled with composite soil according to the soiling protocol given earlier. After soiling, the fabrics were washed with cleaning medium comprising water. Following table gives experimental details and reflectance values measured after soiling (AS) and after wash (AW) . Measured values of reflectance are average value for 5 repetitions unless mentioned otherwise. Table 2: Details of Example 1 and Comparative Examples 1-A to 1-D

It can be seen from the above table that the process of Example 1 wherein the aqueous medium comprises both the polymer and the surfactant and has pH of less than 5 and wherein there is no step of rinsing after treating the fabric results into better cleaning as indicated by higher AW reflectance as compared to processes of Comparative Examples 1-A through to 1-D that are outside the scope of the present invention.

Mixture of non-ionic surfactants

Following experiments were carried out in a manner similar to that of Example 1 except that a mixture of non-ionic surfactants at 0.2 g/L was present in the aqueous medium.

Comparative examples 2-D and 2-E were carried out wherein the aqueous medium comprised 0.1 g/L of un-crosslinked polyacrylic acid (PAA) of molecular weight 2000 and 450,000, respectively, instead of CARBOPOL® 980. The reflectance results along with experimental details are tabulated below. Table 3: Details of Examples 2-5 and Comparative Examples 2-A to 2-E

* sim - simultaneous

** seql - polymer first followed by surfactant *** seq2 - surfactant first followed by polymer

It can be seen that mixture of non-ionic surfactants provides better cleaning as compared to a single non-ionic surfactant. It is also seen that polycarboxylic acid polymer without cross- linking does not provide effective cleaning. It can be also seen that the process involving step of treating fabric sequentially with polymer and surfactant in any order provides good cleaning although the results with simultaneous treatment are better.

Effect of the treatment of pick-up of carbon soot

Each cotton fabric treated with 0.1 g/L EO3, 0.1 g/L EO7 and

0.1 g/L of carbopol (Example 6) was subjected to soiling by carbon soot according to the protocol described earlier. In the process of comparative example 6-A, the aqueous medium had 0.2 g/L cetyl trimethyl ammonium bromide instead of EO3 and EO7. In process of comparative example 6-B, the treated fabric was subjected to a step of rinsing with water before subjecting to soiling by carbon soot. All the treated fabrics were dried after soiling and cleaned with water. Reflectance was measured after soiling (AS) and after wash (AW) . The results are tabulated below.

Table 4: Details of Example 6 and Comparative Examples 6-A to 6-B

Effect of type of surfactant Processes of following examples were carried out in a manner similar to process of Example 1 except that the aqueous medium comprised 0.1 g/L of CARBOPOL® 980 and different surfactants were used as tabulated below.

Table 5: Details of Examples 7-10

From the results, it is clear that the process of present invention provides effective cleaning with various non-ionic and anionic surfactants.

Effect of cleaning medium and its pH

In the following examples, fabrics were treated in a manner similar to that of Example 1. However treated fabrics were cleaned with cleaning medium having pH ranging from 7 to 11.4

Table 6: Examples 11-14 and comparative example 14-A

* Ftc - fabric treatment composition of Example 1 was used as cleaning medium.

Example 14-A shows that cleaning medium with pH 5 does not result in effective cleaning, and that the fabric treatment composition, when used for cleaning rather than treating fabric, is not effective. Examples 11-14 show that the cleaning efficacy improves with increase in pH. Cleaning in hard water

Fabric was treated and cleaned in water of 48 French Hardness (FH) in Example 14, and the reflectance values are tabulated along with that of Example 1 (reproduced)

Table 7: Details of Examples 1 and 15

It is seen that the reflectance after washing does not deteriorate strongly when hard water is used, unlike conventional detergent compositions where the performance deteriorates severely with hardness of water. For example, washing the same fabric monitors in 3 g/L SURF EXCEL®, a commercially available surfactant, AW reflectance drops to 58 at 48 FH from about 65 at 0 FH, a drop of 7 reflectance units. In comparison, with the method of present invention, the performance in 48 FH drops by only 3 reflectance units (from 65 to 62) .

Effect on various substrates Following processes were carried out in a manner similar to that of Example 1, except that fabric swatches made of polycotton and polyester were used instead of cotton. The reflectance values are tabulated below. Table Details of Examples 16-19

The above table further demonstrates the effect of pH of cleaning medium. It can be seen that particularly when the substrate is polycotton or polyester, better results are obtained when the pH of cleaning medium is greater than 7, with the cleaning efficacy directionally increasing with the increase in pH.

It will be appreciated that the above examples clearly and sufficiently describe the manner in which the process of the present invention can be practiced. It will be further appreciated that the process of the present invention is capable of meeting the object of providing a process for treatment of fabric that reduces soiling of fabrics, improves efficacy of subsequent cleaning, and is effective on various types of fabrics including cotton, polycotton and polyester.

Claims

1. A process for treatment of a fabric comprising the steps of:

(a) contacting the fabric with a cross-linked polycarboxylic polymer and a surfactant in presence of an aqueous medium having pH less than 5, and;

(b) drying the fabric, where the fabric is not rinsed with water between the steps (a) and (b) .

2. A process as claimed in claim 1 wherein cationic surfactant is not greater than 100 ppm of the aqueous medium.

3. A process as claimed in any one of the preceding claims wwhheerreeiinn tthhee aammoouunntt ooff ppoollyymmeerr contacted per cm² area of fabric is from 0.1 to 200 mg.

4. A process as claimed in any one of the preceding claims wwhheerreeiinn tthhee aammoouunntt ooff ssuurrffaaccttaanntt contacted per cm² area of the fabric is from 0.1 to 200 mg.

5. A process as claimed in any one of the preceding claims comprising a further step of washing the treated fabric with a cleaning medium comprising water and having pH greater than 5.

6. A process as claimed in claim 5 wherein said cleaning medium comprises hydroxide, carbonate, bicarbonate, phosphate, silicate or aluminate of an alkali metal or ammonium.

7. A process as claimed in claim 5 or 6 wherein said cleaning medium further comprises a surfactant.