WO2010119022A1

WO2010119022A1 - Polymer particles

Info

Publication number: WO2010119022A1
Application number: PCT/EP2010/054799
Authority: WO
Inventors: Stuart Anthony Barnett; Craig Warren Jones; Stephen Thomas Keningley; Andrew Philip Parker
Original assignee: Unilever Plc; Unilever N.V.; Hindustan Unilever Limited
Priority date: 2009-04-16
Filing date: 2010-04-13
Publication date: 2010-10-21
Also published as: CN102395608B; CL2011002577A1; BRPI1011346A2; CN102395608A; ZA201107132B; EP2419459A1; WO2010119065A1; CN102395668A; ZA201107131B; EP2419500A1

Abstract

According to the invention there is provided polymer particles comprising (i) a hydrophobically modified polymer having a lower critical solution temperature of from 5 to 60 ˚C (particularly polyvinyl alcohol backbone having one or more hydrocarbyl group substituents of from C₄ to C₂₂ carbon chain length); the polymer particle is provided as a polymer matrix comprising multiple discrete benefit agent (ii) entities embedded in the polymer matrix, wherein, the ratio of (i) to (ii) is from 1:50 to 99:1 parts by weight; also provided are surfactant compositions comprising the polymer particles, a process to make the polymer particles and to the use of the polymer particles to deliver a benefit agent to fabric and/or to a wash or rinse medium during a wash process.

Description

POLYMER PARTICLES

FIELD OF INVENTION

The present invention relates to polymer particles, surfactant compositions comprising the polymer particles, in particular liquid laundry detergent compositions, processes for making the polymer particles, and to the use of the polymer particles to deliver a benefit agent to fabric or to a wash and/or rinse medium during a wash process.

BACKGROUND

Laundry treatment compositions generally contain ingredients which provide a fabric benefit to laundered clothes. Examples of such ingredients include perfumes, enzymes, bleaches, shading pigments and fabric conditioning agents. These materials are also generally the most expensive components of the laundry composition. It can be advantageous to protect (for example by encapsulation) fabric benefit ingredients when they are included in laundry formulations due to potential incompatibility with other ingredients in the formulation. This incompatibility can cause the formulation to be unstable, or involve unwanted reactivity of the fabric benefit ingredient and so cause the efficacy of the fabric benefit ingredient to be adversely effected.

Various encapsulation processes have been developed, including firstly, complex coacervation between polymers of opposite charge, gum arabic-gelatin is an example of such a method; secondly, matrix encapsulation using polymers that are liquid above a certain temperature and harden when cooled, an example material is agar; matrix encapsulation where the polymer chains are ionically bound using mono- or polyvalent metal ions, for example, alginate & calcium (Ca²⁺) or kappa carrageenan & potassium (K⁺).

US 2005/0043200 discloses an aqueous liquid laundry detergent comprising visible beads which are in the form of a liquid core surrounded by a semi- permeable membrane formed by the interaction between a cationic material and an anionic material.

US 6,380,150 discloses a liquid detergent comprising a surfactant, a stably suspended oil containing gelatin beads, a polyacrylate polymeric thickener and water.

WO 2004/031271 discloses a water soluble package comprising a polymeric film, the polymeric film comprising a polymeric backbone derived from a polymer which is water soluble, and one or more dehvatising groups attached to the backbone, the derivatising group(s) being derived from a parent material having a ClogP of from 0.5 to 6. The package is an enclosure and will release all contents in a single dose.

WO2006/116099 discloses a liquid detergent composition comprising surfactants, at least one suspending agent, beads and water.

WO2007/125523 discloses a liquid detergent comprising a liquid matrix and visibly distinct beads, and additionally a hueing agent which is present in the liquid matrix, the beads, or both.

WO 2005/075261 discloses water-soluble and/or water-dispersible particles comprising an active ingredient uniformly dispersed in a matrix comprising polyvinyl alcohol. There remains a need for a benefit agent delivery system which is stable in product formulations so that no, or less leakage of the benefit agent occurs, while disintegrating completely during the wash process so as to ensure that no resides remain on the textiles at the end of the wash cycle.

SUMMARY OF INVENTION

We have found that a polymer particle as defined herein fulfils at least one of the aforementioned needs.

In a first aspect the invention provides a polymer particle comprising (i) a hydrophobically modified polymer having a lower critical solution temperature of from 5 to 60^°C, which has a polyvinyl alcohol backbone having one or more hydrocarbyl group substituents of from C₄ to C22 carbon chain length; the polymer particle is provided as a polymer matrix comprising multiple discrete benefit agent(ii) entities embedded in the polymer matrix, wherein, the ratio of (i) to (ii) is from 1 :50 to 99:1 parts by weight.

An advantage of the polymer particle over the cited documents is the reduced leakage of the benefit agent.

Another advantage of the polymer particle is that the benefit agents embedded in the polymer matrix can be released gradually (i.e. not all at one time) into the wash medium. This means that the benefit agents can be released over a varied time period, in contrast to the water soluble package of WO 2004/031271 which releases its payload as a single portion.

A second aspect of the invention provides a surfactant composition comprising from 0.05 to 10 wt.% of the polymer particles of the first or second aspects, and - A -

from 2 to 70 wt.% of a surfactant selected from an anionic surfactant, a nonionic surfactant, a cationic surfactant, or a mixture thereof.

A further advantage of the polymer particles is that they can deliver benefit agents which are usually incompatible with a product's surfactant system due to stability issues. This is in contrast to the water soluble package of WO 2004/031271 which delivers a single composition.

A preferred surfactant composition is a liquid laundry detergent composition comprising an anionic surfactant, a nonionic surfactant, or a mixture thereof.

A advantage that the polymer particles provides to the liquid laundry detergent composition is that they are preferably clear in formulation, the particles can be used to provide useful benefit agents which if not protected from the liquid composition would opacify it.

A third aspect of the invention provides a process for making the polymer particles of the first or second aspects, the process comprising the steps of:

(a) provision of an aqueous mixture of a hydrophobically modified polymer as defined herein, and a fabric benefit agent;

(b) drying the aqueous mixture to remove whole or part of the water from the aqueous mixture to form one or more polymer particles; and,

(c) optionally adapting the dried polymer particle(s) to the desired shape and/or size.

A further aspect of the invention provides a process for making the polymer particles of the first or second aspects, the process comprising the steps of: (a) provision of an aqueous mixture of a hydrophobically modified polymer as defined herein, and a fabric benefit agent;

(b) addition of droplets of the aqueous mixture of step (a) to an aqueous surfactant solution having a surfactant concentration of greater than 1.3 x 10^"4 mol/l, and having a temperature above that of the lower critical solution temperature of the hydrophobically modified polymer.

In yet another aspect of the invention, the use of the polymer particles according to the first aspect, to deliver a benefit agent to fabric or to a wash and/or rinse medium during a wash process is provided.

In a further aspect the invention provides a polymer particle comprising (i) a hydrophobically modified polymer having a lower critical solution temperature of from 5 to 60^°C; the polymer particle is provided as a polymer matrix comprising multiple discrete benefit agent(ii) entities embedded in the polymer matrix, wherein, the ratio of (i) to (ii) is from 1 :50 to 99:1 parts by weight; and, the modified polymer is insoluble in an aqueous anionic and/or nonionic surfactant mixture where the surfactant concentration is greater than 5g/l.

DETAILED DESCRIPTION OF THE INVENTION

The amount of components present in the various surfactant compositions quoted herein are wt.% of total composition unless otherwise stated.

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or ratios of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Polymer Particles

It is preferred that the hydrophobically modified polymer is made from a polymer backbone which is water soluble.

By 'water-soluble' used herein in relation to the polymer, it is meant that the polymer should dissolve in water such that when 0.1 g, preferably 0.3g, more preferably 0.5g of polymer is placed into 1 L of water at room temperature and shaken at 100 RPM on a rotator shaker at 293K for 2 hours, then removed from solution by filtering through a sieve or filter paper of appropriate size and dried, then the weight of the polymer removed is less than 95% by weight of that added. This feature indicates the water solubility characteristics of the polymer prior to hydrophobic modification, in that the polymer is preferred to be a water soluble polymer prior to hydrophobic modification.

By 'insoluble' used herein in relation to the modified polymer, it is meant that the polymer should not dissolve in surfactant solutions. Such that when 1g/L of the modified polymer is placed into an aqueous surfactant mixture (a mixture of linear alkylbenze sulfonate (LAS) and nonionic surfactant (which is a reaction product of aliphatic C12 to C15 primary linear alcohols with ethylene oxide (7 EO)) where the surfactant concentration is greater than 5g/l at room temperature and shaken at 100 RPM on a rotator shaker at 293K for 2 hours, then removed from solution by filtering through a sieve or filter paper of appropriate size and dried, then the weight of the modified polymer removed is within 95% by weight of that added.

Preferably the modified polymer is insoluble in an aqueous surfactant mixture (a mixture of linear alkylbenze sulfonate (LAS) and nonionic surfactant (which is a reaction product of aliphatic C12 to C15 primary linear alcohols with ethylene oxide (7 EO)) where the surfactant concentration is from 5 to 800g/l, more preferably greater from 5 to 500g/l, for example 50 to 500g/l. Lower critical solution temperature (LCST) is a characteristic of a material that demonstrates good solubility in aqueous solutions at low temperatures, but separates from solution when the temperature is raised above the LCST (see Feil et al., Macromolecules 1993, 26, 2496-2500). The 'aqueous solutions' where the LCST effect referred to is shown for polymers of the present invention include water and aqueous surfactant solutions (including aqueous surfactant mixtures).

Preferred LCST ranges of the modified polymer are from 5 to 55^°C, more preferably from 5 to 50^°C.

In a preferred embodiment of the invention, the modified polymer has a LCST in water of greater than 20^°C, more preferably greater than 30^°C.

The polymer particle is provided as a polymer matrix comprising multiple discrete benefit agent entities embedded in the polymer matrix.

The polymer particles of the invention can further be described as a polymer matrix into which are immobilised multiple discrete benefit agents, i.e. the benefit agents are an integral part of the polymer or polymer matrix of which the polymer particle is formed.

The discrete benefit agent entities can be the same or different benefit agents embedded in a polymer matrix. A discrete benefit entity means, for example, an actual perfume encapsulate, or an actual droplet of softening oil.

For the avoidance of doubt, the polymer particles of the invention do not include encapsulates or packages of a polymeric material forming a wall which holds a free (i.e. not embedded or immobilised in the polymer matrix as defined) benefit agent or composition inside a cavity defined by the polymeric wall. Encapsulates wherein the polymer particle of the invention further comprises a shell of polymer material is within the scope of the invention.

The polymer particles may themselves be encapsulated into a package by a film of a film forming polymer having a polyvinyl alcohol backbone having one or more hydrocarbyl group substituents of from C₄ to C22 carbon chain length. Suitable method for encapsulating with such a film are known from WO 2004/031271. The polymer particles can be provided in the form of a film.

The polymer particle comprises a hydrophobically modified polymer (i), and a fabric benefit agent (ii), in a ratio of from 1 :50 to 99:1 parts by weight, preferably from 1 :40 to 95:1 parts by weight.

The polymer particle preferably has a size of greater than or equal to 50μm. Preferably the particle size is from 50μm to 2cm, preferably from 50μm to 1 cm. Alternatively the polymer particle may have a size of from 0.1 mm to 50mm; or from 0.5 to 10mm or from 1 to 10mm for example. An advantage of particles of size greater than 50μm is that they are visible to a consumer and can be used to provide a visual cue to the end consumer of the technical advantage of the surfactant composition.

The size of the polymer particle means the maximum value of the largest dimension of the particle.

The size of the polymer particle can be measured using graded sieves and it is that which is retained or passes through such sieves.

Polymers suitable for use as whole or part of the backbone of the hydrophobically modified polymer are preferably selected from the group consisting of polyvinyl alcohol, polyvinyl acetate, cellulose ethers, polyethylene oxide, starch, polyvinylpyrrolidone, polyacrylamide, polyvinyl methyl ether-maleic anhydride, polymaleic anhydride, styrene maleic anhydride, hydroxyethylcellulose, methylcellulose, polyethylene glycols, carboxymethylcellulose, polyacrylic acid salts, alginates, acrylamide copolymers, guar gum, casein, ethylene-maleic anhydride resin series, polyethyleneimine, ethyl hydroxyethylcellulose, ethyl methylcellulose and hydroxyethyl methylcellulose. Copolymeric mixtures of polymers derived from the aforementioned backbones are also suitable. Preferably the polymer has a backbone comprising side chain hydroxyl groups.

The most preferred backbone for the polymer comprises polyvinyl alcohol, and the polymer preferably has an average molecular weight of from 1 ,000 to 300,000 Daltons, preferably from 2,000 to 100,000 Daltons.

Polyvinyl alcohol (PVOH) can be supplied in a form comprising a certain amount of polyvinyl acetate (PVAc), in that a level of the hydroxyl groups (OH) of the

PVOH material is substituted with acetate groups (OCOCH₃). Hydrolysis of PVAc is a common way to make PVOH. Thus the PVOH used herein generally comprise at some PVAc. The PVOH materials (either before or after hydrophobic modification) may comprise from 0.01 to 40% PVAc, preferably from 0.01 to 20%, more preferably from 0.1 to 15%, most preferably 0.5 to 10%, based on the % of the total number of monomers making up the polymer. As used herein, the term PVOH includes PVOH compounds with a PVAc level as previously defined.

The polymer is modified to comprise hydrophobic substituents. One method of modification is detailed in example 1.

Preferred hydrophobic derivatisation groups include those based on parent groups selected from acetals, ketals, esters, fluorinated organic compounds, ethers, alkanes, alkenes and aromatics. Highly preferred hydrophobic substituents are hydrocarbyl groups of C₄ to C22 carbon chain length. These hydrocarbyl groups may be alkyl or alkenyl based, which can be straight chain, branched or comprise rings; it may also or alternatively incorporate aromatic moieties.

More preferably the hydrocarbyl group has a carbon chain length of from C₄ to C20, even more preferably from C₄ to C15, most preferably from C₄ to C10, for example, from C₄ to C₈.

Hydrocarbyl chain lengths greater than 22 are undesirable as the parent material from which the dehvatising group is obtained reacts poorly or not at all with the polymeric backbone. Hydrocarbyl groups shorter than 4 provide negligible additional hydrophobicity.

Especially preferred materials suitable for use to introduce the hydrophobic dehvatisation groups onto the polymer are aldehydes such as butyraldehyde, octyl aldehyde, dodecyl aldehyde, 2-ethyl hexanal, cyclohexane carboxy-aldehyde, citral and 4-aminobutyraldehyde dimethyl acetal.

The hydrophobic material is preferably present in the polymer at a level from 0.1 to 40% by weight, based on the total weight of the polymer, more preferably from 2 to 30%, most preferably from 5 to 15%.

Where the polymeric backbone is based on polyvinyl alcohol (PVOH), the hydrophobic derivatisation material is preferably present at a level such that the number ratio of the hydrophobic groups to the free hydroxyl pairs on the backbone is from 1 :3 to 1 :30, more preferably from 1 :4 to 1 :20, most preferably 1 :7 to 1 :15.

Additional modifying groups may be present on the polymer backbone. For instance, amines may be preferably included as a modifying group since this makes the polymer more soluble in response to, for instance, the change in pH and/or ionic strength from the wash to the rinse liquor.

A particularly preferred polymer particle comprises a hydrophobic modified polymer of formula:

wherein the average number ratio of z to x is within the range of from 1 :200 to 1 :6, y is in the range of from 0.01 to 20% based on the % of total number of monomers making up the polymer (x + y + z), and R is a hydrophobic group being an alkyl or alkenyl group having from 3 to 21 carbon atoms, preferably from 3 to 6 carbon atoms. Most preferably R is C₃H₇.

The polymer particles themselves can further be surrounded by a shell to form core-shell type materials.

It is preferred that the polymer particles are visible, in that they are of sufficient size to be seen, and/or that they comprise a dye or pigment, which can be included in the polymer particle in addition to the fabric benefit agent. Such particles are highly preferred in laundry compositions as they provide an attractive visual cue for consumers. Benefit Agents

Various benefit agents can be incorporated into the polymer particles. Any benefit agent which can provide a benefit to a substrate which is treated with a surfactant composition can be used.

Preferred benefit agents are in the laundry field, for example fabric benefit agents, and benefit agents which provide a benefit to a laundry wash and/or rinse medium.

Preferred examples include perfumes (both free and encapsulated), enzymes, antifoams, shading dyes and/or pigments, detergency builders, fabric conditioning agents (for example water-insoluble quaternary ammonium materials and/or silicones), sunscreens, antioxidants, reducing agents, sequestrants, colour care additives, density matching polymers, photobleaches, unsaturated oils, emollients and antimicrobial agents.

A preferred embodiment of the invention includes a disintegrant in addition to the benefit agent.

The polymer particles are particularly suitable for use with particulate or water soluble benefit agents.

Plasticiser and/or Crystallinity Disruptor

The polymer particle preferably incorporates a plasticiser and/or crystallinity disruptor. It is to be understood that the term "plasticiser" and phrase "crystallinity disruptor" are interchangeable such that a reference to one is an implicit reference to the other.

The plasticiser influences the way the polymer chains react to external factors such as compression and extensional forces, temperature and mechanical shock by controlling the way that the chains distort/realign as a consequence of there intrusions and their propensity to recover to their former state. The key feature of plasticisers is that they are highly compatible with the polymer particle and are normally hydrophilic in nature. The plasticiser will depend on the nature of the polymer particle in question.

Generally, plasticisers suitable for use with PVOH-based polymer particles have - OH groups in common with the -CH₂-CH(OH)-CH₂-CH(OH)- polymer chain of the polymer particle.

Their mode of functionality is to introduce short chain hydrogen bonding within the hydroxyl groups and this weakens adjacent chain interactions which inhibits swelling of the aggregate polymer mass - the first stage of polymer dissolution.

Water itself is a suitable plasticiser for PVOH polymer particles but other common plasticisers include: polyhydroxy compounds e.g. glycerol, trimethylolpropane, diethylene glycol, triethylene glycol, sorbitol, dipropylene glycol, polyethylene glycol, starches e.g. starch ether, esterified starch, oxidized starch and starches from potato, tapioca and wheat, cellulosics/carbohydrates e.g. amylopectin, dextrin, carboxymethylcellulose and pectin. Amines are particularly preferred plasticisers. SURFACTANT COMPOSITIONS

The polymer particles of the invention can be incorporated in surfactant compositions. Various surfactants are listed below.

Preferred surfactant compositions are those in the field of home and personal care, in particular in the field of laundry, hair and oral care.

The surfactant compositions comprise from 0.05 to 10 wt.% of the polymer particles as previously described, and from 2 to 70 wt.%, preferably 10 to 30 wt.% of a surfactant selected from an anionic surfactant, a nonionic surfactant, a cationic surfactant, or a mixture thereof.

The polymer particles are present in the surfactant composition at a level of from 0.05 to 10 wt.%, preferably from 0.2 to 10 wt.%, more preferably from 0.2 to 5 wt.%.

LAUNDRY TREATMENT COMPOSITIONS

The polymer particles of the invention are preferably incorporated in a laundry treatment composition.

The laundry treatment composition may take the form of an isotropic liquid, a surfactant-structured liquid, a granular, spray-dried or dry-blended powder, a tablet, a paste, a molded solid or any other laundry detergent form known to those skilled in the art. The composition is preferably a liquid laundry composition.

The laundry treatment composition may be a detergent composition for use in the main wash; alternatively it may be a composition for addition to a rinse cycle, for example a fabric conditioner. A preferred laundry treatment composition comprises from 0.05 to 10 wt.% of the polymer particles as defined herein, and from 2 to 70 wt.% of a textile compatible carrier selected from an anionic surfactant, nonionic surfactant, a mixture thereof, or a cationic fabric softening compound.

The polymer particles are present in the laundry treatment composition at a level of from 0.05 to 10 wt.%, preferably from 0.2 to 10 wt.%, more preferably from 0.2 to 5 wt.%.

The laundry detergent compositions additionally comprise from 2 to 70 wt.% of an anionic surfactant, nonionic surfactant, a mixture thereof, or a cationic fabric softening compound.

PROCESS OF PREPARATION

In one embodiment, the invention provides a process for making the polymer particles of the invention, the process comprising the steps of:

A preferred embodiment of the invention provides a process for making the polymer particles of the invention, the process comprising the steps of:

(a) provision of an aqueous mixture of a hydrophobically modified polymer as defined herein, and a fabric benefit agent; (b) addition of droplets of the aqueous mixture of step (a) to an aqueous surfactant solution having a surfactant concentration of greater than 1.3 x 10^~4 mol/l, and having a temperature above that of the lower critical solution temperature of the hydrophobically modified polymer.

A particular advantage of this preferred process is that the polymer particles can be formed in-situ during the formulation of liquid laundry treatment compositions. This has the twin advantages that manufacturing costs are reduced (due to the fact that the polymer particles are not made separately from the laundry treatment compositions), and that therefore the amount of waste materials is reduced (as there is no separate manufacture of the polymer particles).

The temperature of the aqueous mixture (a) is below the LCST temperature of the hydrophobically modified polymer. Preferably the temperature is at least 5^°C lower that the LCST of the hydrophobically modified polymer.

Preferably the addition of droplets step (step (b)) is carried out by injection of mixture (a) into the aqueous surfactant solution.

Suitable injection methods include:-

• Vibrating nozzles (either single for matrix polymer particles or concentric for core-shell polymer particles (e.g. Droppo™, Rieter-Automatik) dispensing directly into the surfactant solution, the polymer particle size being governed by the nozzle size, flow rate, polymer solution viscosity and the vibration frequency. The nozzle can also be fitted with an electrostatic charge generator to enhance polymer particle separation.

• JetCutter™ (geniaLabs™), where the polymer particles are formed by cutting through the polymer stream using a cutting disk. • Direct injection into the surfactant solution through a nozzle (either single for matrix polymer particles or concentric for core-shell polymer particles). Detachment of the polymer particle from the nozzle tip is achieved by either vibrating the nozzle or by adjusting the flow rate of the surfactant solution.

In each case the nozzle can be either outside the surfactant solution or submerged in the surfactant solution.

Preferably the addition of droplets is carried out in a dropwise fashion.

Preferably the temperature of the aqueous surfactant solution having a surfactant concentration of greater than 1.3 x 10^"4 mol/l is at least 5^°C higher than the lower critical solution temperature of the hydrophobically modified polymer.

The temperature of the aqueous mixture (a) can be raised to a level of not greater than the lower critical solution temperature of the hydrophobically modified polymer. Preferably the temperature of the aqueous mixture (a) is raised to a level of not greater than 5^°C lower than the lower critical solution temperature of the hydrophobically modified polymer.

Preferably the surfactant solution of the addition of droplets step (step (b)) of the preferred process is a liquid laundry treatment composition. This results in a liquid laundry treatment composition comprising the polymer particles. In this way the polymer particles can be formed in-situ during the processing of the liquid laundry treatment composition.

The polymer particles formed from the aqueous surfactant solution process can optionally be isolated after formation by any isolation method, for example filtration. SURFACTANT

The composition comprises between 2 to 70 wt.% of a surfactant, most preferably 10 to 30 wt.%. In general, the nonionic and anionic surfactants of the surfactant system may be chosen from the surfactants described "Surface Active Agents" Vol. 1 , by Schwartz & Perry, lnterscience 1949, Vol. 2 by Schwartz, Perry & Berch, lnterscience 1958, in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981. Preferably the surfactants used are saturated.

Suitable nonionic detergent compounds which may be used include, in particular, the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are Cβ to C22 alkyl phenol- ethylene oxide condensates, generally 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic C₈ to Ci₈ primary or secondary linear or branched alcohols with ethylene oxide, generally 5 to 40 EO.

Suitable anionic detergent compounds which may be used are usually water- soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals. Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher C₈ to Ci₈ alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl Cg to C20 benzene sulphonates, particularly sodium linear secondary alkyl C10 to C15 benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum. The preferred anionic detergent compounds are sodium Cu to Ci₅ alkyl benzene sulphonates and sodium C12 to C18 alkyl sulphates. Also applicable are surfactants such as those described in EP-A-328 177 (Unilever), which show resistance to salting-out, the alkyl polyglycoside surfactants described in EP-A-070 074, and alkyl monoglycosides.

Preferred surfactant systems are mixtures of anionic with nonionic detergent active materials, in particular the groups and examples of anionic and nonionic surfactants pointed out in EP-A-346 995 (Unilever). Especially preferred is surfactant system that is a mixture of an alkali metal salt of a C16 to C18 primary alcohol sulphate together with a C12 to C15 primary alcohol 3 to 7 EO ethoxylate.

The nonionic detergent is preferably present in amounts greater than 10%, e.g. 25 to 90 wt. % of the surfactant system. Anionic surfactants can be present for example in amounts in the range from about 5 wt.% to about 40 wt.% of the surfactant system.

CATIONIC FABRIC SOFTENING COMPOUND

Preferred cationic fabric softening compounds are water insoluble quaternary ammonium material which comprises a compound having two C12-18 alkyl or alkenyl groups connected to the nitrogen head group via at least one ester link. It is more preferred if the quaternary ammonium material has two or more ester links.

BUILDERS OR COMPLEXING AGENTS

The laundry treatment composition may optionally comprise from 0 to 50 wt.% of a detergency builder. Preferably builder is present at a level of from 1 to 40 wt.%. Builder materials may be selected from 1 ) calcium sequestrant materials, 2) precipitating materials, 3) calcium ion-exchange materials and 4) mixtures thereof.

It is preferred that when an insoluble inorganic builder, e.g., zeolite is used, the size is in the range 0.1 to 10 microns (as measured by The Mastersizer 2000 particle size analyzer using laser diffraction ex Malvern™).

Examples of calcium sequestrant builder materials include alkali metal polyphosphates, such as sodium thpolyphosphate and organic sequestrants, such as ethylene diamine tetra-acetic acid.

Examples of precipitating builder materials include sodium orthophosphate and sodium carbonate.

Examples of calcium ion-exchange builder materials include the various types of water-insoluble crystalline or amorphous aluminosilicates, of which zeolites are the best known representatives, e.g. zeolite A, zeolite B (also known as zeolite P), zeolite C, zeolite X, zeolite Y and also the zeolite P-type as described in EP-A-0,384,070.

The composition may also contain 0-50 wt.% of a builder or complexing agent such as ethylenediaminetetraacetic acid, diethylenetriamine-pentaacetic acid, alkyl- or alkenylsuccinic acid, nitrilothacetic acid or the other builders mentioned below. Many builders are also bleach-stabilising agents by virtue of their ability to complex metal ions.

Zeolite and carbonate (carbonate (including bicarbonate and sesquicarbonate) are preferred builders. The composition may contain as builder a crystalline aluminosilicate, preferably an alkali metal aluminosilicate, more preferably a sodium aluminosilicate. This is typically present at a level of less than 15 wt.%. Aluminosilicates are materials having the general formula:

0.8-1 .5 M₂O. AI₂O₃. 0.8-6 SiO₂

where M is a monovalent cation, preferably sodium. These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates contain 1.5-3.5 SiO₂ units in the formula above. They can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. The ratio of surfactants to aluminosilicate (where present) is preferably greater than 5:2, more preferably greater than 3:1.

Alternatively, or additionally to the aluminosilicate builders, phosphate builders may be used. In this art the term 'phosphate' embraces diphosphate, triphosphate, and phosphonate species. Other forms of builder include silicates, such as soluble silicates, metasilicates, layered silicates (e.g. SKS-6 from Hoechst).

Preferably the laundry detergent formulation is a non-phosphate built laundry detergent formulation, i.e., contains less than 1 wt.% of phosphate.

SHADING AGENT

The laundry treatment composition preferably comprises a blue or violet shading agent in the range from 0.0001 to 0.01 wt.%. The shading agents reduce the perception of damage to many coloured garments and increase whiteness of white garments.

The shading agents are preferably selected from blue and violet dyes of the solvent disperse basic, direct and acid type listed in the colour index (Society of Dyers and Colourists and American Association of Textile Chemists and Colorists

2002).

Preferably a direct violet or direct blue dyes is present. Preferably the dyes are bis-azo, tris-azo dyes or triphendioxazine dye. The carcinogenic benzidene based dyes are not preferred.

Bis-azo copper containing dyes such as direct violet 66 may be used.

The most preferred bis-azo dyes have the following structure:

or R^2

wherein: ring D and E may be independently naphthyl or phenyl as shown;

Ri is selected from: hydrogen and C1 -C4-alkyl, preferably hydrogen;

R2 is selected from: hydrogen, C1-C4-alkyl, substituted or unsubstituted phenyl and substituted or unsubstituted naphthyl, preferably phenyl;

R₃ and R₄ are independently selected from: hydrogen and C1-C4-alkyl, preferably hydrogen or methyl;

X and Y are independently selected from: hydrogen, C1-C4-alkyl and C1-C4- alkoxy; preferably the dye has X= methyl; and, Y = methoxy and n is 0, 1 or 2, preferably 1 or 2.

Preferred bis-azo dyes are direct violet 7, direct violet 9, direct violet 11 , direct violet 26, direct violet 31 , direct violet 35, direct violet 40, direct violet 41 , direct violet 51 , and direct violet 99.

Preferred solvent and disperse dyes, are selected from, mono-azo or anthraquinone dyes, most preferably, solvent violet 13, disperse violet 27 disperse violet 26, disperse violet 28, disperse violet 63 and disperse violet 77.

A preferred pigment is pigment violet 23. ENZYMES

The laundry treatment composition preferably comprises one or more enzymes which provide cleaning performance and/or fabric care benefits. Examples of suitable enzymes include, but are not limited to, hemicellulases, peroxidases, proteases, cellulases, xylanases, lipases, phospholipases, esterases, cutinases, pectinases, mannanases, pectate lyases, keratinases, reductases, oxidases, phenoloxidases,- lipoxygenases, ligninases, pullulanases, tannases, pentosanases, malanases, arabinosidases, hyaluronidase, chondroitinase, laccase, and amylases, or mixtures thereof. A typical combination is an enzyme cocktail that may comprise, for example, a protease and lipase in conjunction with amylase. When present in a cleaning composition, the aforementioned additional enzymes may be present at levels from about 0.00001 wt.% to about 2 wt.%, from about 0.0001 wt.% to about 1 wt.% or even from about 0.001 wt.% to about 0.5 wt.% enzyme protein by weight of the composition.

Preferred enzymes are cellulases.

FLUORESCENT AGENT

The composition preferably comprises a fluorescent agent (optical brightener). Fluorescent agents are well known and many such fluorescent agents are available commercially. Usually, these fluorescent agents are supplied and used in the form of their alkali metal salts, for example, the sodium salts. The total amount of the fluorescent agent or agents used in the composition is generally from 0.005 to 2 wt.%, more preferably 0.01 to 0.1 wt.%. Preferred classes of fluorescer are: Di-styryl biphenyl compounds, e.g. Tinopal (Trade Mark) CBS-X, Di-amine stilbene di-sulphonic acid compounds, e.g. Tinopal DMS pure Xtra and Blankophor (Trade Mark) HRH, and Pyrazoline compounds, e.g. Blankophor SN. Preferred fluorescers are: sodium 2-(4-styryl-3-sulfophenyl)-2H-napthol[1 ,2- d]trazole, disodium 4,4'-bis{[(4-anilino-6-(N methyl-N-2 hydroxyethyl) amino 1 ,3,5- triazin-2-yl)]annino}stilbene-2-2' disulfonate, disodium 4,4'-bis{[(4-anilino-6- morpholino-1 ,3,5-triazin-2-yl)]amino} stilbene-2-2' disulfonate, and disodium 4,4'- bis(2-sulfoslyryl)biphenyl.

PERFUME

Preferably the composition comprises a perfume. The perfume is preferably in the range from 0.001 to 3 wt.%, most preferably 0.1 to 1 wt.%. Many suitable examples of perfumes are provided in the CTFA (Cosmetic, Toiletry and

Fragrance Association) 1992 International Buyers Guide, published by CFTA Publications and OPD 1993 Chemicals Buyers Directory 80th Annual Edition, published by Schnell Publishing Co.

It is commonplace for a plurality of perfume components to be present in a formulation. In the compositions of the present invention it is envisaged that there will be four or more, preferably five or more, more preferably six or more or even seven or more different perfume components.

In perfume mixtures preferably 15 to 25 wt.% are top notes. Top notes are defined by Poucher (Journal of the Society of Cosmetic Chemists 6(2):80 [1955]). Preferred top-notes are selected from citrus oils, linalool, linalyl acetate, lavender, dihydromyrcenol, rose oxide and cis-3-hexanol.

Perfume and top note may be used to cue the fabric care benefit of the invention.

If the laundry treatment composition takes a liquid form, then it is preferred that the composition does not contain a peroxygen bleach, e.g., sodium percarbonate, sodium perborate, and peracid. POLYMERS

The composition may comprise one or more polymers. Examples are carboxymethylcellulose, poly(ethylene glycol), polyvinyl alcohol), polycarboxylates such as polyacrylates, maleic/acrylic acid copolymers and lauryl methacrylate/ acrylic acid copolymers.

Polymers present to prevent dye deposition, for example poly(vinylpyrrolidone), poly(vinylpyridine-N-oxide), and poly(vinylimidazole), are preferably absent from the formulation.

HYDROTROBE

For compositions in the form of a liquid, it is useful to include a hydrotrope, which prevents liquid crystal formation. The addition of the hydrotrope thus aids the clarity/transparency of the composition. Suitable hydrotropes include but are not limited to propylene glycol, ethanol, urea, salts of benzene sulphonate, toluene sulphonate, xylene sulphonate or cumene sulphonate. Suitable salts include but are not limited to sodium, potassium, ammonium, monoethanolamine, triethanolamine. Preferably, the hydrotrope is selected from the group consisting of propylene glycol, xylene sulfonate, ethanol, and urea to provide optimum performance. The amount of the hydrotrope is generally in the range of from 0 to 30%, preferably from 0.5 to 30%, more preferably from 0.5 to 30%, most preferably from 1 to 15%.

BLEACH PRECURSORS

Bleach precursors (e.g. tetra-acetylene diamine and sodium percarbonate) cannot be added directly to a liquid formulation as the resulting peracid species would not be stable. By encapsulating the two precursors within beads the generation of peracid can be prevented until the bead is introduced into the main wash. Experimental

Example 1 Preparation of the Hydrophobically Modified Polymeric Material A 10wt% solution of PVOH in water was prepared by placing 10Og PVOH (Mowiol 20-98 (trade name), ex Kuraray Specialities) and 90Og demineralised water into a flask and heating to 7O⁰C. To this, 10ml of hydrochloric acid (36% aqueous solution) was added to catalyse the reaction and then butyraldehyde was added. The mixture was then stirred at 7O⁰C for 5 hours under an inert atmosphere, after which time the heating was stopped and agitation continued for a further 20 hours at room temperature. The reaction mixture was then brought to a pH of 7 using a sodium hydroxide solution.

The resulting solution was precipitated into acetone to yield the acetalised PVOH polymer and washed repeatedly with acetone (500ml) and then water (50ml). It was then dried under vacuum at 7O⁰C overnight to yield a white polymer.

Example 2

A solution comprising 1 part hydrophobically modified PVOH solution (15% active) was mixed with 2 parts of a slurry containing an encapsulated perfume (53% solids, 20% perfume loading) with a trace of Pigment Violet 23. The resulting solution was then added dropwise through a 22-guage hypodermic needle to a surfactant solution containing approximately 65% nonionic/anionic surfactants at a temperature of 50⁰C. At this temperature, the PVOH/perfume encap slurry forms polymer particles of approximately 1.5mm in diameter. When the desired quantity of polymer particles have been formed, the surfactant solution is cooled to ambient temperature.

No evidence of leakage of fabric benefit agent is observed after 14 days. Example 3

A solution comprising 1 part hydrophobically modified PVOH solution (15% active) was mixed with 2 parts of a slurry containing an encapsulated perfume (53% solids, 20% perfume loading) plus 5ml of a 1g/l Acid Blue 98 solution. The resulting solution was then added dropwise through a 22-guage hypodermic needle to a surfactant solution containing approximately 65% nonionic/anionic surfactants at a temperature of 50⁰C. At this temperature, the PVOH/perfume encap slurry forms polymer particles of approximately 1.5mm in diameter. When the desired quantity of beads have been formed, the surfactant solution is cooled to ambient temperature.

No evidence of leakage of fabric benefit agent is observed after 14 days.

Example 4 1g of polymer particles containing perfume encapsulates and Pigment Violet 23 were formed in 35ml of a concentrated liquid detergent containing approximately 45% nonionic/anionic surfactants in a similar method to examples 1 and 2. The resulting mixture of polymer particles in surfactant was then added to a washing machine (Miele Novotronic W844) containing a 3kg load (1 kg woven cotton sheeting, 1 kg knitted cotton, 1 kg 65:32 woven cotton/polyester) and washed using the standard 40⁰C cotton wash cycle using Prenton water (26°FH, 2:1 Ca:Mg ratio). After washing, half of the load was line dried, half was tumble dried (Miele drier, normal setting). On drying, the presence of perfume encaps was determined by rubbing the fabric. In both cases, perfume was released. Visual analysis of the fabric revealed no residues and none were observed inside the machine.

Example 5

1g of polymer particles in the form of a polymer film was shaped into 6mm star shapes. These particles contained perfume encapsulates (85% by weight). The stars were added to 35ml of a concentrated liquid detergent containing approximately 45% nonionic/anionic surfactants. This was then added to a washing machine (Miele Novotronic W844) containing a 3kg load (1 kg woven cotton sheeting, 1 kg knitted cotton, 1 kg 65:32 woven cotton/polyester) and washed using the standard 40⁰C cotton wash cycle using Prenton water (26°FH, 2:1 Ca:Mg ratio). After washing, half of the load was line dried, half was tumble dried (Miele drier, normal setting). On drying, the presence of perfume encapsulates was determined by rubbing the fabric. In both cases, perfume was released. Visual analysis of the fabric revealed no residues and none were observed inside the machine.

This shows that the polymer matrix releases its benefit agents onto the fabric under wash conditions without leaving residues on the fabric.

Example 6

Two polymer particles in the form of films were prepared as follows:-

Polvmer Film 1 (according to the invention)

10ml Mowiflex LPFX416 (15% solution) + 5ml water + 2ml 0.1 g/l Solvent Blue 37 solution containing 1 % Neodol 25-7 (to produce a stable dye dispersion in the water). Mowiflex LPFX416 is a hydrophobically modified PVOH available from Kuraray.

Polymer Film 2 (reflecting the subject matter of US 2005/075261 ) As above but replacing 10ml of Mowiflex with 5ml Mowiol 3-85 (15% solution) and 5ml glycerol (15% solution). Mowiol 3-85 is a standard PVOH material without any hydrophobic substitution, available from Kuraray. The Mowiol grade used is a close as possible to that used in US 2005/0075261 paragraph [0025] - "Mowiol 8- 83"; the comparative example thus shows the technical effect for the hydrophobic modification. Both particles were in the form of films, and were dried at room temperature for 72 hours, and cut into shapes for inclusion into surfactant compositions.

0.5g of each film was cut into 5mm squares and placed into 20ml detergent formulation (45 wt.% surfactant) and placed on a bottle roller. The absorption at 580nm was measured after 48 hours to determine the amount of dye leakage from the film. This shows whether the polymer particles in the form of a film are unstable due to leakage of their benefit agent into the formulation. The integrity of the shapes was also observed.

Absorption data:

After 48 hours film 1 = 0.15585 film 2 = 0.29322

So the dye loss from film 2 is approximately twice that from film 1. This shows that the polymer particles of polymer film 1 (according to the invention) display a leakage improvement over the polymer particles of polymer film 2 (un-modified PVOH according to the closest prior art US 2005/075261 ).

Also, the shapes formed from film 2 had broken up after 48 hours while those from film 1 were still intact.

Claims

1. A polymer particle comprising (i) a hydrophobically modified polymer having a lower critical solution temperature of from 5 to 60^°C, which has a polyvinyl alcohol backbone having one or more hydrocarbyl group substituents of from C₄ to C22 carbon chain length; the polymer particle is provided as a polymer matrix comprising multiple discrete benefit agent(ii) entities embedded in the polymer matrix, wherein, the ratio of (i) to (ii) is from 1 :50 to 99:1 parts by weight.

2. A polymer particle according to claim 1 , wherein the polyvinyl alcohol backbone has an average molecular weight of from 1 ,000 to 300,000 Daltons.

3. A polymer particle according to claim 1 or claim 2, wherein the particle size is from 50μm to 2 cm.

4. A polymer particle according to any one of the preceding claims, wherein the benefit agent is selected from the group consisting of:- free perfumes, encapsulated perfumes, enzymes, antifoams, shading dyes and/or pigments, detergency builders, water-insoluble quaternary ammonium materials, bleach precursors, silicones, sunscreens, antioxidants, reducing agents, sequestrants, colour care additives, density matching polymers, photobleaches, unsaturated oils, emollients and antimicrobial agents.

5. A polymer particle according to claim 4, additionally comprising a disintegrant.

6. A polymer particle according to any one of claims 1 to 5, wherein the polymer particle is itself encapsulated by a film of a film-forming polymer having a polyvinyl alcohol backbone having one or more hydrocarbyl group substituents of from C₄ to C22 carbon chain length.

7. A polymer particle according to any one of claims 1 to 6 which is in the form of a film.

8. A surfactant composition comprising from 0.05 to 10 wt.% of the polymer particles of any one of claims 1 to 7, and from 2 to 70 wt.% of a surfactant selected from an anionic surfactant, a nonionic surfactant, a cationic surfactant, or a mixture thereof.

9. A surfactant composition according to claim 8, wherein the composition is a liquid laundry detergent composition comprising an anionic surfactant, a nonionic surfactant, or a mixture thereof.

10. A process of forming the polymer particles of claims 1 to 4, comprising the steps of:

(a) provision of an aqueous mixture of a hydrophobically modified polymer as defined in claim 1 , and a benefit agent;

11. A process of forming the polymer particles of any one of claims 1 to 14, comprising the steps of: (a) provision of an aqueous mixture of a hydrophobically modified polymer as defined in claim 1 , and a benefit agent;

(b) addition of droplets of the aqueous mixture of step (a) to an aqueous surfactant solution having a surfactant concentration of greater than 1.3 x 10^~4 mol/l, and having a temperature above that of the lower critical solution temperature of the hydrophobically modified polymer.

12. A process according to claim 11 , wherein the addition step (b) is carried out by injection.

13. A process according to claim 11 or claim 12, wherein the temperature of the surfactant solution is at least 5^°C higher than the lower critical solution temperature of the hydrophobically modified polymer.

14. A process according to any one of claims 11 to 13, wherein the temperature of the aqueous mixture (a) is raised to a level of not greater than the lower critical solution temperature of the hydrophobically modified polymer.

15. Use of the polymer particles according to any one of claims 1 to 7, to deliver a benefit agent to fabric or to a wash and/or rinse medium during a wash process.