EP2794840B1

EP2794840B1 - Fabric treatment composition

Info

Publication number: EP2794840B1
Application number: EP12794348.8A
Authority: EP
Inventors: Somnath Das; Amitava Pramanik
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2011-12-20
Filing date: 2012-12-03
Publication date: 2016-08-10
Anticipated expiration: 2032-12-03
Also published as: ES2602271T3; EP2794840A1; BR112014015521A2; AR089323A1; CN103998595B; BR112014015521A8; ZA201404542B; WO2013092184A1; CN103998595A

Description

Field of the invention

The present invention relates to a composition and a method for treating laundry, to make it more susceptible to cleaning in the subsequent wash cycle, in particular making the fabric more hydrophilic, and improve oily soil cleaning.

Background of the invention

Better cleaning of fabric articles during washing has been the primary focus of laundry detergent research for decades. However, since the present day consumer has ever higher demands for the effectiveness of washing detergents, substantial improvements remain to be desired, especially relating to cleaning of oily soils.
WO2010/105943A relates to the use of polymers comprising carboxyl groups in combination with bivalent cations for producing a protective layer on a textile sheet material and to textile treatment agents, in particular washing and cleaning agents containing said polymers in a suitable form of administration, in order to enable the formation of a protective layer on textile sheet materials.
US2006046950A (Penninger and Bastigkeit, 2006) teaches a detergent composition for cleaning textile materials comprising a combination of a soil release-capable alkyl or hydroxyalkyl cellulose derivative and a hygroscopic polymer selected from the class consisting of polypeptides, hydrogels, polyvinyl alcohol, the polyalkylene glycols, the homopolymers of acrylic acid, methacrylic acid, and maleic acid, copolymers of acrylic acid, methacrylic acid, and maleic acid and mixtures of the homo and copolymers. The use of the hygroscopic polymers in combination with the cellulose derivatives is said to result in improved cleaning performance.
GB994353 (Domestos, 1965) teaches that mixtures of certain polymeric materials, when incorporated into unbuilt detergent compositions based on synthetic surface active agents, provide enhanced anti-redeposition as compared to activity of individual polymers alone when added alone to same detergent compositions.
US4007305 (Kakar et al, 1977 ) addresses the problem of providing satisfactory nondurable finishes to textiles which impart optimum soil release and soil repellent properties. According to US4007305 , the textiles must be treated with an alkaline aqueous medium having pH value of 7.5-11 and containing water soluble hydrophilic soil release polymer having carboxylic acid groups and a dispersed hydrophobic soil repellent fluorochemical, while the removal of oily (hydrophobic) soils remains to be desired.
On the other hand, 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. The treatments, besides being substrate-specific, are relatively difficult to practice in household.
The object of the present invention is to provide a composition that improves the cleaning and removal of oily soils and stains upon the subsequent wash.
It is another object of the invention to render a fabric surface more hydrophilic by deposition of a particle layer which helps in cleaning for the next time wash.
It is yet another object of the invention to improve wicking, i.e. the spreadability of stains and soils on the fabric.
It is another object that the composition is in the form of a fabric conditioner composition.
It is another object to provide fabric softening benefits to the fabric.
We have found that a fabric treatment composition comprising metal salt and a carboxylic polymer, in the presence of a salt of weak organic acid and a polysaccharide, provides good oily soil removal upon the subsequent wash.

Summary of the invention

Accordingly, in a first aspect, the present invention provides a fabric treatment composition comprising 5 - 35% by weight of a poly aluminium chloride (PAC) metal salt, 1 - 15% by weight of a carboxylic polymer, 1 - 15% by weight of a salt of weak organic acid, wherein the weak organic acid is selected from di- and tri-carboxylic acids containing ß-hydroxyl groups and phenolic acids with ortho-hydroxyls, 0.1 - 5% by weight of a polysaccharide, and 33 - 90 % water; and wherein the pH of the composition is between 8 and 10; and wherein the ratio of metal salt: carboxylic polymer ratio is at between 2:1 and 8:1.
In a second aspect, the present invention provides a process for treating a fabric comprising the steps of treating the substrate with a composition according to the invention and leaving the substrate to dry.
In a third aspect, the present invention provides a bottled fabric conditioner comprising the compositions according to the invention.
The invention relates to improved cleaning upon the subsequent wash. This is commonly referred to in the art as next time cleaning benefit, or secondary cleaning benefit.
These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of' or "composed of." In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

Detailed description of the invention

Accordingly, in a first aspect, the present invention provides a fabric treatment composition comprising poly aluminium chloride (PAC), a carboxylic polymer, a salt of weak organic acid, a polysaccharide, and water; and wherein the ratio of metal salt: carboxylic polymer ratio is at between 2:1 and 8:1.

Poly aluminium chloride

Poly aluminium chloride is a known polyelectrolyte. The poly aluminium chloride (PAC) may be defined as a non-stoichiometric oligomer of aluminium hydroxychloride having general formula [Al(OH)_aCl_b]_n where the value of a is preferably in the range 1.5 to 1.9 and b preferably in the range 1.1 to 1.5, wherein a+b=3. The aluminium content is typically 12-20%.
Without wishing to be bound by a theory, it is thought that the aluminium in the PAC forms a complex with the polymer according to the invention, and the complex is thought to deposit onto the fabric surface, thereby forming a sacrificial layer.
Commercial PAC may have small amount of impurities including traces of SO₄ ^2-, CO₃ ^2-; NO₃ ^-, Br^-, HCO₃ ^-, and HSO₄ ^-; but such impurities are typically present in a concentration of less than 2%, more preferably less than 1%, still more preferably less than 0.5% or even less than 0.1 % by weight of the PAC.
The PAC is present in the composition in a concentration of between 5 - 35% by weight, preferably at least 10%, more preferably at least 15% or even at least 20% by weight of the composition, but preferably less than 30% by weight of the composition.

Bivalent metal salt

On top of the poly aluminium chloride, the composition may comprise an additional metal salt. The bivalent metal salt is found to further complex with the carboxylic polymer of the invention, which is thought to provide improved deposition onto fabrics.
The bivalent metal salt when present in the composition is preferably in a concentration of 1-15% by weight of the composition, preferably at least 2%, more preferably at least 5%, still more preferably at least 8%, or even at least 10% by weight of the composition.
Preferred bivalent metal ions typically include alkaline earth metal ions, pseudo transition metal ions and transition metal ions, preferably giving white salt precipitates, more preferred are magnesium, zinc, calcium, most preferably magnesium and zinc. Preferred anions are anions giving water soluble salts. Preferred examples are chloride and nitrate.
In order to achieve full solubility, the total amount of the bivalent metal salt and PAC is preferably less than 45%, still more preferably less 40%, or even less than 35% by weight of the composition and the metal salt (PAC+bivalent) : carboxylic polymer ratio is between 2:1 and 8:1.

Carboxylic polymer

Preferred carboxylic polymers (or polycarboxylates) are polyacrylates, polymaleates, polyacetates, polyhydroxyacrylates, polyacrylate/polymaleate and polyacrylate/ polymethacrylate copolymers, aminopolycarboxylates and polyacetal carboxylates.
Poly(acrylic acid) or PAA is the most preferred polymer. The monomer of poly (acrylic acid) is acrylic acid. In a water solution at neutral pH, many of the side chains of PAA will lose their protons and acquire a negative charge. PAA is thus understood to be a polymer of repeating units of -[CH2-CH(COOH)]_n-.
Preferably the polymers has a molecular weight of at least 1000 u (u = atomic mass unit, also known as Dalton, D or Da), still more preferably at least 2000 u, but typically not more than 100000 u, more preferably not more than 50000 or even not more than 10000 u.
It has been found that when applying a polymer with a molecular weight above 100000, may cause re-deposition of soil onto the fabric, therefore polymers with a Mw above 100000u are preferably not used.
The polymer is present in the composition in a concentration of between 1 - 15% by weight, preferably at least 2%, more preferably at least 4%, still more preferably at least 6%, or even at least 8% by weight of the composition, but preferably less than 12% by weight of the composition.
For obtaining the right hydrophilicity of the fabric the ratio of the metal salt (PAC alone or PAC and bivalent metal salt) to the polymer is between 2:1 and 8:1, more preferably the ratio is between 5:2 and 5:1.

Salt of Weak organic acid

The organic acids used herein are organic acids that do not dissociate completely under laundry rinse conditions and hence weak organic acids.
The weak organic acid is selected from di- and tri-carboxylic acids containing β-hydroxyl groups, and phenolic acids with ortho-hydroxyls. Tricarboxylic chelating ligands include but are not limited to citric acid are isocitric acid, aconitic acid, propane-1,2,3-tricarboxylic acid (tricarballylic acid, carballylic acid), trimesic acid. Other examples include gluconic, tartaric, EDTA or their derivatives. Citric acid is the most preferred.
The salt is preferably water soluble, the preferred cation is selected from sodium, potassium, and ammonium.
The salt of the organic acid is present in the composition in a concentration of between 1 - 15% by weight, preferably the concentration is at least 3%, more preferably at least 5%, still more preferably at least 8%, or even at least 10%.

Polysaccharides

It is further found that the addition of a polysaccharide provides improved deposition of the complex onto the fabric and improves the formation of a sacrificial layer that can be removed on the subsequent wash, together with later deposited stains.
Preferred polysaccharides are celluloses, more preferably alkyl cellulose. The most preferred is methyl cellulose preferably having a methoxy substitution between 27.5-31.5% by weight of the methyl cellulose. The methyl cellolose preferably has a degree of substitution (D.S., average number of substituent groups attached to the ring hydroxyls) between 1.5 and 1.9, and a resulting viscosity of 15 - 5500 mPa.s for a 2% solution at 20°C and an average molecular weight of 14000 - 100000 u.
The polysaccharide is present in the composition in a concentration of from 0.1 to 5% by weight of the composition, preferably from 0.1 to 4% by weight, more preferably from 0.1 to 2% by weight.

Optional ingredients

Common cleaner adjunct ingredients like perfume, anti-redeposition agents, fluorescers, shading dyes and optical brighteners may also be included.
It is further found that the addition of a small amount of low molecular weight poly vinyl alcohol (PVA) at a concentration of 0.5 to 3% by weight of the composition provides improved oily soil removal. The molecular weight of the PVA is preferably between 1000 and 25000 u, more preferably less than 23000 u. High molecular weight PVA (i.e. above 25000) cause redeposition of particulate soils, such as mud.
It is further found that the addition of non ionic surfactants provides improved deposition onto the fabrics and forming a sacrificial layer to be removed, together with later deposited stains upon the subsequent wash. Preferred non-ionic surfactants include ethoxylated alcohols, preferably in the form of a condensation product of an alcohol having an alkyl chain length of between 8 and 18 carbon atoms and 3 to 10 moles of ethylene oxide per mol of alcohol. The non-ionic surfactant is preferably present in a concentration of 0.5 to 2% by weight of the composition.

Solvents

The composition is preferably an aqueous liquid, comprising 33 to 90% of water. However, compositions, wherein the aqueous liquid is a solvent and water mixture, are also contemplated. The solvents are preferably lower alcohols, more preferably ethanol and iso-propanol, or combinations thereof.
The solvent is typically present in the aqueous liquid in a concentration of between 1 and 10%, more preferably between 2 and 5% by weight of the composition.

Laundry treatment process

The invention provides a process for treating a substrate (i.e. a fabric), comprising the steps in sequence of applying the composition according to the invention to laundry article in the rinse conditioning step, preferably the ultimate rinse step, of the laundry main wash and leaving it to dry. The fabric is preferably not rinsed after contacting with the composition.

Product format

The composition may be packaged in the form of any commercially available liquid composition, typically in the form of a bottle containing the liquid. Liquid unit dose is also contemplated.
The dosage of the composition to the rinse liquor is typically in the amount of 1 to 10 g/L. In a typical front load washing machine, the dosage is preferably between 2 and 7 g/L, while in a top load machine the design is typically between 1 and 4 g/L, and for hand wash typically 5 to 10 g/L.

Examples

The invention will now be illustrated by means of the following non-limiting examples.

Ingredients:

1. Polyaluminum chloride (commercial grade, Arya, ex Grasim)
2. Distilled water
3. Polyacrylic acid 15K A.R. Aldrich
4. Polyvinyl alcohol 1.8 KA.R. Aldrich
5. Magnesium chloride A.R. (Merck)
6. Bombay Dyeing desized fabrics
7. Citric acid monohydrate (Sigma)
8. Sodium hydroxide A.R. (Merck)
9. Methyl cellulose (Sigma)

Application to fabrics:

10 x 10 cm swatches were cut from white the cotton and 67:33-Polyester/cotton, ex Bombay dyeing.
The fabrics were soaked in the solution mixture at liquor to cloth ratio of 5 for 10 minutes in 0 °fH water with occasional stirring. The fabrics were squeezed and dried in an air drier at ambient temperature.

Soiling of fabrics:

The 10 cm X 10 cm fabric swatches were soiled using 200 microlitres of composite soil (comprising iron oxide, carbon soot, and glycerol tri oleate). The fabrics were then aged for 24 hours.

Washing protocol:

The fabrics were washed at 0 °fH water using Surf Excel Quickwash (ex Unilever, India) at 3 g/L dose. The fabrics were soaked in the detergent solution for 30 minutes at liquor to cloth ratio of 5 followed by regimented brushing on each side of the swatch for 5 times. The fabric were then rinsed in 0 °fH water 3 times at liquor to cloth ratio of 10. The fabrics were dried and the reflectance values were taken.

Reflectance measurement:

The reflectance was measured using a Greytech McGrath reflectometer in UV excluded mode and the R 460* value after wash was noted. The average reflectance after soiling, but before wash= 58.45
In the experiments the R460* values are taken for the composition according to the invention and comparative examples alike.

EXAMPLE 1: Cleaning efficacy.

Example composition 1 is according to the invention, while comparative examples A - F show compositions lacking one or more of the ingredients, and example G is an untreated control. In this example the swatches are prepared with the composition of the invention, then soiled and washed. The table below shows the compositions and the reflectance values of the experiments.

The concentrations are given in g/L in the wash liquor.

	Ingredients					*R 460 after wash**
Exp t No	PAC (g/L)	PAA (g/L)	citrat e (g/L)	Mg chloride (g/L)	Methyl cellulose (g/L)	cotton	poly cotton
1	0.5	0.2	0.2	0.1	0.05	77.77	85.54
A	0.5	0.2	0.2	0.1		74.69	81.62
B	0.5					73.69	80.75
C	0.2	0.2				72.10	80.74
D			0.2			72.26	81.83
E				0.1		73.21	80.79
F					0.05	74.00	82.43
G						73.33	77.42

The table above shows that the composition according to the invention shows a higher reflectance (i.e. better cleaning) than any of the comparative tests.

EXAMPLE 2: Effect of the presence of an additional metal ion.

This example demonstrates the role of a combination of trivalent and bivalent metal ions on cleaning. In this experiment different PAC to bivalent metal ratios are compared to a control, to a composition without the additional metal ion and a composition with the additional metal ion, but without PAC.

	Ingredients					*R 460 after wash**
Expt No	PAC (g/L)	PAA (g/L)	citrate (g/L)	Mg chloride (g/L)	Methyl cellulose (g/L)	cotton	poly cotton
1	0.5	0.2	0.2	0.1	0.05	77.77	85.54
4	1.4	0.8	0.8	0.6	0.05	78.38	87.02
5	2	0.8	0.8	0	0.05	76.70	85.34
G						73.33	77.42
H		0.8	0.8	0.6	0.05	76.45	80.23

The table above shows that the composition according to the invention shows a higher reflectance (i.e. better cleaning) than any of the comparative tests. The composition containing both PAC and a bivalent metal salt perform the best. The composition with PAC alone is also performing well. The composition (H) without PAC and having only the bivalent metal is not performing well on poly/cotton material.

Claims

A fabric treatment composition comprising:
a 5 - 35% by weight of a poly aluminium chloride (PAC) metal salt,

b 1 - 15% by weight of a carboxylic polymer,

c 1 - 15% by weight of a salt of weak organic acid, wherein the weak organic acid is selected from di- and tri-carboxylic acids containing β-hydroxyl groups and phenolic acids with ortho-hydroxyls,

d 0.1 - 5% by weight of a polysaccharide, and

e 33 - 90 % water; and
wherein the pH of the composition is between 8 and 10; and wherein the ratio of metal salt : carboxylic polymer ratio is at between 2:1 and 8:1.
A composition according to claim 1, wherein the composition further comprises between 1 and 15% by weight of bivalent metal salt.
A composition according to any one of the preceding claims, wherein the polymer is poly acrylic acid.
A composition according to any one of the preceding claims, wherein the acid is citric acid.
A composition according to any one of the preceding claims, wherein the molecular weight of the polyacrylic acid is less than 100000 u.
A composition according to any one of the preceding claims, wherein the metal salt : polymer ratio is between 5:2 and 5:1.
A composition according to any one of the preceding claims, wherein the aqueous liquid is a solvent and water mixture, comprising of 1-10% solvent.
A composition according to claim 7, wherein the solvent is selected from ethanol and/or isopropanol.
A composition according to anyone of the preceding claims, wherein the polysaccharide is methyl cellulose, having a molecular weight of 14000- 100000.
A composition according to anyone of the preceding claims further comprising 0.5 to 3% by weight of a 1000 to 25000 molecular weight poly vinyl alcohol.
A composition according to anyone of the preceding claims further comprising 0.5 to 2% by weight of a non ionic surfactant.
A process for treating a fabric comprising the steps of:
a treating the substrate with a composition according to anyone of claims 1 to 11, and

b leaving the substrate to dry
A bottled fabric conditioner comprising the compositions according to any one of claims 1-11.