Fabric care composition

Abstract

 Core shell polymer particles comprising a benefit agent, preferably a sugar polyester are delivered to fabric during laundering and give long lasting adherence of the benefit agent to fabric during laundering. The core comprises a benefit agent and a polymer and is prepared using miniemulsion polymerisation. A method of depositing a benefit agent, preferably a sugar polyester, onto a substrate by means of such a composition is also disclosed, as are corresponding uses.

Description

TECHNICAL FIELD

[0001] The present invention relates to core shell polymer particles comprising a benefit agent, preferably a sugar polyester, and their uses, such as delivery to fabric during laundering and long lasting adherence of the benefit agent to fabric during laundering. Laundry treatment compositions containing particles according to the invention, provide, for example, softening benefits to fabric, which are protected from surfactants during washing. The process for preparing the particles comprises miniemulsion polymerisation. The invention further relates to a method of depositing a benefit agent, preferably a sugar polyester, onto a substrate by means of such a composition.

BACKGROUND OF THE INVENTION

[0002] The deposition of a benefit agent onto a substrate, such as a fabric, is a well known method of imparting desirable properties to the substrate. In laundry applications the range of "benefit agents" is diverse and includes fabric softeners and conditioners, soil release polymers, shape retention agents, anti-crease agents, ease of ironing aids, perfumes, lubricants, texturising agents, insecticide repellents, fungicides, photofading inhibitors, fluorescers, sunscreens and many others. Deposition of a benefit agent is used, for example, in fabric treatment processes such as fabric conditioning to confer, for example, softening and/or lubrication benefit to the fabric.

[0003] Conventionally, the deposition of the benefit agent has had to rely upon attractive forces between the oppositely charged substrate and the benefit agent. For example, cotton is negatively charged and thus requires a positively charged benefit agent in order for the benefit agent to be substantive to the cotton, i.e. to have an affinity for the cotton so as to absorb onto it.

[0004] However, adverse charge considerations can place severe limitations upon the inclusion of benefit agents in compositions where an active component thereof is of an opposite charge to that of the benefit agent. For example, cationic fabric conditioning agents are incompatible with anionic surfactants in laundry washing compositions, hence fabric conditioning products are usually separate from main wash products. Furthermore, the substantivity of the benefit agent can be severely reduced and/or the deposition rate of the benefit agent can be reduced because of the presence of incompatible charged species in the compositions. The conventional way around this problem is to add benefit agents during the rinsing step of a treatment process so as to avoid adverse effects from other charged chemical species present in the main wash compositions. This has clear cost disadvantages to the consumer and instigates the need for two separate products instead of one.

[0005] In light of these problems, it has recently been proposed to deliver a benefit agent in a form whereby it is substituted onto another chemical moiety, which itself has an affinity for the substrate in question, thereby enabling delivery of charged species during the main wash stage of the laundry process.

[0006] However, a further problem is that longevity of adherence to a surface, such as a fabric, of non-silicone lubricants, such as mineral oils and sugar polyesters, in a surfactant containing environment, such as a laundry main wash liquor, is inherently poor because surfactants are characteristically very efficient at washing away such substances. In the context of laundry products, the need for protection from surfactants of non-silicone benefit agents, which have been deposited onto a fabric surface, promotes the need for new deposition and protection systems.

PRIOR ART

[0007] EP 1502646 A1 (The Procter & Gamble Company) discloses microcapsules for use in liquid detergents having a core and a polyelectrolyte complex shell in the form of a semipermeable membrane having specific bursting force and density properties. The shell is an ionic complex of polycations and polyanions. The core is a perfume.

[0008] EP1244768 B1 (BASF Aktiengesellschaft) discloses microcapsules of 1 - 100 micron in size that have a liquid core made of a hydrophobic material including a perfume substance and a capsule envelope, which can be obtained by i) radical polymerization of ethylenically unsaturated monomers comprising 30 to 100 weight percent of one or more C1 -C24 -alkylester of acrylic and/or methacrylic acid, 0 to 70 weight percent of one bifunctional or polyfunctional monomer, 0 to 40 weight percent of other monomers or ii) acid-induced condensation of melamine formaldehyde precondensates and/or the C1 -C 4 -alkylethers thereof. Detergent or cleaning agent compositions containing the microcapsules are also disclosed.

[0009] European patent application, published under the number EP 1432782, is directed to a water dispersible particle comprising a deposition enhancing part of one or more polymeric units and a benefit agent attached to the deposition enhancing part. Preferably the deposition aid has a hydrolysable group (based on esters), such as Cellulose Mono-Acetate (CMA). The CMA grafted particles exhibit enhanced wash deposition.

[0010] WO 2004/056890 is directed towards a process for the preparation of polysaccharide grafted latex particles which comprises conventional emulsion polymerisation, and to the materials thus produced. The particles have been used as carriers for benefit agents, including softeners, for deposition under main wash conditions. However, constraints on the amount of benefit agents which can be incorporated into the particles and the types of monomer units that can be used, which are inherent to conventional emulsion polymerisation, are inevitable.

[0011] Our co-pending patent application, PCT/EP2005/004779, unpublished at the filing date of this application, is directed towards a process, which uses miniemulsion polymerisation, for the preparation of polysaccharide grafted polymer particles containing a lubricant. Certain particles produced by the process and uses thereof are also disclosed. The particles facilitate deposition of the lubricant to fabric during the main wash part of a laundering process.

[0012] Our co-pending patent application PCT/EP2005/005121, unpublished at the filing date of this application, is directed towards compositions comprising a water-soluble or dispersible polysaccharide having a hydrophobic agent bonded thereto by a hydrolytically stable bond and a sugar polyester (SPE). SPE is a biodegradable lubricating agent, which has environmental benefits over silicone.

[0013] Despite these advances, the need remains for deposition systems which are capable of delivering benefit agents to a substrate, particularly during the main wash, and protecting them from being washed away by surfactants.

[0014] We have now surprisingly found that a benefit agent, such as a sugar polyester, can be deposited onto a fabric and that the longevity of substantivity to the fabric is vastly improved, even throughout a main wash cycle containing surfactants, if a deposition system based on a core shell particle is used.

DEFINITION OF THE INVENTION

[0015] A first aspect of the invention provides a polymer particle comprising a core and a shell, wherein the core comprises a benefit agent which is a lubricant and a polymer comprising consisting of monomer units which contain at least one ethylenically unsaturated group capable of undergoing addition polymerisation and are derived from monomers selected from the group consisting of:-

a) monomers with a solubility in water of less than 0.1 g/l, and/or

b) monomers with a solubility in water of from 0.1 to 30 g/l, and

c) optionally, monomers with a solubility in water of greater than 30 g/l, and/or

d) optionally, cross linkers, and

wherein the shell comprises monomer units selected from b), and optionally c) and/or optionally d).

[0016] A second aspect of the invention provides a process for the preparation of the particles according to the first aspect, wherein the process for preparation of the core comprises miniemulsion polymerisation of monomers.

[0017] A third aspect of the invention provides a laundry treatment composition comprising the particles of the first aspect. Uses of this laundry treatment composition in the treatment of fabric and to provide a protection benefit to the benefit agent from surfactants during a laundry process are also provided.

[0018] The invention further provides methods of treating fabric, comprising contacting the fabric with the polymer particle of the first aspect of the invention, comprising a cationic or a nonionic deposition aid.

[0019] In a further aspect, the invention provides the use of a particle of the first aspect to provide a protection benefit to the benefit agent from surfactants during a laundry process, for example cotton.

[0020] Without wishing to be bound by theory, it is believed that the presence of the polymer in the core protects the benefit agent from surfactants during a wash process. The protection is conferred before and after the benefit agent has been deposited onto a surface. For example, during a laundry process, whilst the particle is present in the wash liquor, the polymer keeps the benefit agent bound up within the particle thereby preventing it from being leached out of the particle by the surfactants, thus keeping it available for deposition onto the fabric. After deposition of the particle onto fabric, the polymer in the core protects the benefit agent from being washed away by surfactants, thus enhancing longevity of substantivity of the benefit agent to the fabric. By protection benefit as used herein is meant protection of the benefit agent from the action of surfactants during a wash process, for example as suggested above.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention is directed towards core shell polymer particles, comprising a core, a shell and a benefit agent. The benefit agent is present in the core. The core and the shell comprise a polymer, which comprises monomer units.
The polymer particles of the invention are usually approximately spherical and of typical colloidal dimensions.

[0022] Particle diameters may range from about 30 to 500 nm (The Encyclopaedia of Polymer Science and Engineering, Second Edition, Volume 8, Page 647, John Wiley and Sons Inc. (1987)).

[0023] Where the particles of the invention are described herein as latex particles, the term "latex" or "latex particle" is defined as a stable colloidal dispersion of a polymeric substance in an aqueous medium.

[0024] The polymer particles of the invention can comprise a wide range of monomeric units. By "monomer units" as used herein is meant the monomeric units of the polymer chain, thus references to "a polymer particle comprising insoluble monomer units" as used herein means that the polymer particles is derived from insoluble monomers, and so forth.

[0025] The monomer units are derived from monomers which are suitable for free radical polymerisation. Therefore, the monomer contains at least one ethylenically unsaturated group capable of undergoing addition polymerisation.

[0026] The monomers may be selected according to their solubilities such that the core comprises a polymer comprising monomer units which are derived from monomers selected from the group consisting of:-

a) monomers with a solubility in water of less than 0.1 g/l, and/or

b) monomers with a solubility in water of from 0.1 to 30 g/l, and

c) optionally, monomers with a solubility in water of greater than 30 g/l, and/or

d) optionally, cross linkers,

and the shell comprises monomer units selected from b), and optionally c) and/or optionally d).

[0027] By insoluble as used herein in reference to monomers, is meant that the material is soluble in water (distilled or equivalent) at a concentration of less than 0.1 g/litre, at 25°C, i.e. monomers of type (a) above.

[0028] By low solubility as used herein in reference to monomers, is meant that the material is soluble in water (distilled or equivalent) at a concentration in the range of from 0.1 to 30 g/litre, at 25°C, i.e. monomers of type (b) above.

[0029] By high solubility as used herein in reference to monomers, is meant that the material is soluble in water (distilled or equivalent) at a concentration of greater than 30 g/litre, at 25°C, i.e. monomers of type (c) above.

Monomers

[0030] The core and the shell comprise monomer units which are derived from monomers that are capable of undergoing free radical polymerisation. Suitable classes of such monomers are given in the group consisting of olefins, ethylene, vinyl aromatic monomers, esters of vinyl alcohol with mono-and di-carboxylic acids, esters of α,β-monoethylenically unsaturated mono- and dicarboxylic acids with alcohols, nitriles of α,β-monoethylenically unsaturated carboxylic acids, conjugated dienes, α,β-monoethylenically unsaturated monocarboxylic and dicarboxylic acids and their amides, methacrylic acid and its esters with alcohols and diols, acrylic acid and its esters with alcohols and diols, dimethyl or di-n-butyl maleate, and vinyl-sulfonic acid and its water-soluble salts, and mixtures thereof. The monomer units of the core may be the same as or different from the monomer units of the shell and both the core and the shell may comprise mixtures of monomer units.

[0031] The core and shell may optionally comprise monomers which are cross-linkers. Such crosslinkers may have at least two non-conjugated ethylenically unsaturated double bonds. Examples are alkylene glycol diacrylates and dimethacrylates. A further type of suitable cross-linking monomers are those that are conjugated, such as divinyl benzene. If present, these monomers constitute from 0.1 to 10 % by weight, based on the total amount of monomers to be polymerised in both the core and the shell.

[0032] The monomers a), b), c) and d), as defined above, are preferably selected from the following:-

a) vinyl octate; Vinyl decanote; vinyl laurate; vinyl stearate; esters of acrylic, methacrylic, maleic, fumaric or itaconic acid with decyl, dodecyl, tetadecyl, hexadecyl and octadecyl alcohol,

b) styrene; α-methylstyrene; o-chlorostyrene vinyl acetate; vinyl propionate; vinyl n-butyrate; esters of acrylic, methacrylic, maleic, fumaric or itaconic acid with methyl, ethyl, n-butyl, isobutyl, n-hexyl and 2-ethylhexyl alcohol; 1,3-butadiene; 2,3 dimethyl butadiene; and isoprene,

c) acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, poly (alkylene oxide) monoacrylates and monomethacrylates, N-vinyl-pyrrolidone, methacrylic and acrylic acid, 2-hydroxyethyl acrylates and methacrylates, glycerol acrylates and methacrylates, poly(ethylene glycol) methacrylates and acrylates, n-vinyl pyrrolidone, acryloyl morpholine, vinyl formamide, n-vinyl acetamide and vinyl caprolactone, acrylonitrile (71 g/l), acrylamide, and methacrylamide at levels of less than 10 % by weight of the monomer unit content of the particle; 2-(dimethylamino) ethyl methacrylate, 2-(diethylamino) ethyl methacrylate, 2-(tert-butylamino) ethyl methacrylate, 2 - aminoethyl methacrylate, 2-(2-oxo-1-imidazolidinyl) ethyl methacrylate, vinyl pyridine, vinyl carbazole, vinyl imidazole, vinyl aniline, and their cationic forms after treatment with alkyl halides;

d) vinyltoluenes, divinyl benzene, ethylene glycol diacrylate, 1,2-propylene glycol diacrylate, 1,3-propylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylates, ethylene glycol dimethacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, methylenebisacrylamide, cyclopentadienyl acrylate, and triallyl cyanurate.

[0033] The core may comprise monomer units, which are derived from monomers selected from the group consisting of butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, styrene, vinyl acetate and divinyl benzene, or mixtures thereof.

[0034] Particles of the invention can be optionally comprise monomer units which are derived from monomers of solubility of greater than about 30 g/litre, preferably greater than 35 g/litre, for example 40 to 45 g/litre in water (distilled or equivalent) at 25°C. Such monomers may be utilised in a monomer mixture at levels of up to 10 % based on weight of monomers used.

[0035] The polymer and the benefit agent of the core must be compatible, i.e. phase separation should not occur when the polymerisation of the monomer (which is mixed with the benefit agent) is carried out during the process of the invention. The person skilled in the art will be able to determine which are compatible by performing simple tests, for example, a simple test would be to carry out the polymerisation to form the core, let a sample of the newly formed latex dry into a thin film and look for visual evidence of phase separation - if the film is clear, they are compatible, if opaque they are incompatible. Where an incompatibility exists, dilution of an incompatible polymer with a compatible one may improve its compatibility.

The Benefit Agent

[0036] The core comprises a benefit agent. The benefit agent is a lubricant, such as a silicone, mineral oil, vegetable oil and sugar polyester.

[0037] The invention can suitably extend to encompass a wide range of benefit agents. Suitably, the benefit agent may be selected from the group consisting of fabric softeners, conditioners, soil release polymers, shape retention agents, anti-crease agents, ease of ironing aids, quick drying aids, lubricants, texturising agents, insecticides, insect repellents, fungicides, photofading inhibitors, dyes, pigments, fluorescers, and sunscreens, or mixtures thereof. Benefit agents are preferably chemical and/or mechanical protective agents, such as fabric softeners, conditioners, shape retention agents, anti-crease agents, ease of ironing aids, lubricants, texturising agents, insecticides, insect repellents, fungicides, photofading inhibitors and sunscreens, or mixtures thereof. Cosmetic and pharmaceutical benefit agents may also be used.

[0038] Most preferably, the benefit agent is a biodegradeable lubricant, such as vegetable oils and sugar polyesters. A highly preferred lubricant in the context of the present invention is a sugar polyester (SPE). They are known in fabric conditioners and/or softeners. These materials are non-toxic and inherently biodegradable.

[0039] Typically these materials are the products obtainable by esterification of a sugar, such as a saccharide (or other cyclic polyol), with a fatty material. In the context of the invention, the sugar is preferably a disaccharide, preferably sucrose, that is esterified with fatty acid, wherein the degree of esterification is from 1 (mono) to 8 (octa). The fatty acid preferably has a chain length of from C12 to C22 and may be monounsaturated. Examples of suitable fatty acids are Lauric(C12), Myristic(C14), Palmitic(C16), Stearic(C18), Oleic(C18:1), Behenic(C22) and Erucic(C22:1).

[0040] The Hydrophilic-Lipophilic Balance (HLB) value of the SPE's that are suitable for use in the invention are suitably from 0 to 4, preferably from 0 to 2. HLB is a well known parameter to those skilled in the art and a literature reference is: "Modern Aspects of Emulsion Science", The Royal Society of Chemistry, 1998, page 179.

[0041] Sugar polyesters can be represented by the formula below:-

         C₁₂H₁₄O₃(OR)_n(OH)_8-n

where R = COC_nH_2n+1 or COC_nH_2n-1 (for monounsaturated fatty acids)

[0042] Preferred sugar polyesters are sucrose polyesters. Preferred sucrose polyesters are selected from sucrose tetrastearate and sucrose tetraerucate, sucrose tetralaurate, sucrose tetraoleate, sucrose tetrapalmitate and sucrose tetrapalm kernal, most preferably sucrose tetraerucate. It should be noted that these sucrose polyesters normally contain a spread of degree of substitution on the saccharide rings, for example, sucrose tetrastearate also comprises tristearate, pentastearate, hexastearate, etc. Furthermore, the sugar polyesters may contain traces of surfactant which is separate from the main surfactant and the co-surfactant. The SPE can be a mixture of different fatty acids, such as a mixture of oleate and stearate, for example, palm kernal contains a mixture of lauric acid, stearic acid, myristic acid, palmitic acid and oleic acid.

[0043] A highly preferred sugar polyester for use in the present invention is ER-290 ex Mitsubishi Ryoto, which is a sucrose tetraerucate and according to the manufacturers spec is mainly Pentaerucate, Tetraerucate and Hexaerucate and has a HLB value of 2.

[0044] The lubricant (such as a sugar polyester) can be incorporated into the core at a wide range of levels. For example, of from 0.1 to 99 %, preferably from 50 to 99 % by weight of the total core.

[0045] Further suitable lubricants are amino functional silicone oils such as Rhodorsil Oil Extrasoft supplied by Rhodia Silicones. Other silicones may be selected from those disclosed GB 1,549,180A, EP 459,821A2 and EP 459822A. Other suitable lubricants include any of those known for use as dye bath lubricants in the textile industry.

The Optional Deposition Aid

[0046] The polymer particle of the invention may further comprise a deposition aid, which is preferably cationic or nonionic.

[0047] Preferably, the deposition aid is a polysaccharide. The polysaccharide preferably has a β-1,4-linked backbone.

[0048] Preferably the polysaccharide is a cellulose, a cellulose derivative, or another β-1,4-linked polysaccharide having an affinity for cellulose, such as polymannan, polyglucan, polyglucomannan, polyxyloglucan and polygalactomannan or a mixture thereof. More preferably, the polysaccharide is selected from the group consisting of polyxyloglucan and polygalactomannan. For example, preferred polysaccharides are locust bean gum, tamarind xyloglucan, guar gum or mixtures thereof. Most preferably, where the deposition aid is nonionic, the polysaccharide is locust bean gum.

[0049] The deposition aid may be a cationic polysaccharide or other cationic polymer. Where the deposition aid is cationic, the polysaccharide is cationically modified. Preferred cationic polysaccharides are cationically modified cellulose or guar.

[0050] The polysaccharide acts as a delivery aid/deposition agent for the particle.

[0051] Preferably, the polysaccharide backbone has only β-1,4 linkages. Optionally, the polysaccharide has linkages in addition to the β-1,4 linkages, such as β-1,3 linkages. Thus, optionally some other linkages are present. Polysaccharide backbones which include some material which is not a saccharide ring are also within the ambit of the present invention (whether terminal or within the polysaccharide chain).

[0052] The polysaccharide may be straight or branched. Many naturally occurring polysaccharides have at least some degree of branching, or at any rate at least some saccharide rings are in the form of pendant side groups (which are therefore not in themselves counted in determining the degree of substitution) on a main polysaccharide backbone.

[0053] Preferably, the polysaccharide is present at levels of between 0.1% to 10% w/w by weight of the total amount of monomer in the core and the shell.

[0054] The deposition aid, which is preferably a polysaccharide, is attached to the polymer particle. Attachment may be by means of a covalent bond, entanglement or strong adsorption, preferably by a covalent bond or entanglement and most preferably by means of a covalent bond. By entanglement as used herein is meant that the deposition aid is adsorbed onto the shell during the shell formation stage and consequently, as the polymerisation proceeds and the particle grows in size, part of the adsorbed polysaccharide becomes buried within the interior of the particle. Hence at the end of the polymerisation, part of the polysaccharide is entrapped and bound in the polymer matrix of the shell, whilst the remainder is free to extend into the aqueous phase.

[0055] By strong adsorption as used herein is meant strong adsorption of the polysaccharide to the surface of the particle; such adsorption can, for example, occur due to hydrogen bonding, Van Der Waals or electrostatic attraction between the polysaccharide chains and the particle.

[0056] The deposition aid is thus mainly attached to the particle surface and is not, to any significant extent, distributed throughout the internal bulk of the particle. This is distinct from graft copolymers in which e.g. a polysaccharide may be grafted along the length of a polymer chain. A particle which is formed from a graft copolymer would, therefore, contain polysaccharide throughout the internal bulk of the particle as well as on the particle surface. Thus the particle which is produced when using a polysaccharide as the deposition aid according to the process of the invention can be thought of as a "hairy particle", which is different from a graft copolymer. This feature of the invention provides significant cost reduction opportunities for the manufacturer as much less polysaccharide is required to achieve the same level of activity as systems which utilise polysaccharide copolymers.

[0057] Other types of particle surface morphology may be produced when a deposition aid is attached to the particle of the invention. For example, where a polysaccharide attaches to the particle surface in multiple places, loops may result, or the deposition aid may be in the form of a swollen cationic polymer layer at the particle surface.

The Core Shell Polymer Particle

[0058] When used in laundering, the core shell polymer particle deposits onto the fabric. The core shell polymer particle may be used in the treatment of fabric. Such treatment may provide a softening, conditioning, lubricating, crease reducing, ease of ironing, moisturising, colour preserving and/or anti-pilling, quick drying, UV protecting, shape retaining, soil releasing, texturising, insect repelling, fungicidal, dyeing, and/or fluorescent benefit to the fabric.

[0059] Alternatively, the core shell polymer particle may be incorporated into a laundry treatment composition and used in the treatment of fabric. Where a nonionic deposition aid is used, the fabric is preferably cotton.

[0060] The core shell polymer particle may also be used to confer a protection benefit to the benefit agent from the action of surfactants. The protection is conferred before and after the benefit agent has been deposited onto a surface. For example, during a laundry process, whilst the particle is present in the wash liquor, the polymer keeps the benefit agent bound up within the particle thereby preventing it from being leached out of the particle by the surfactants, thus keeping it available for deposition onto the fabric. After deposition of the particle onto fabric, the polymer in the core protects the benefit agent from being washed away by surfactants, thus enhancing longevity of substantivity of the benefit agent to the fabric.

[0061] The particle may be used in the manufacture of a laundry treatment composition to provide a protection benefit to the benefit agent from surfactants during a laundry process. By protection benefit is meant protection of the benefit agent from the action of surfactants during a wash process, for example as suggested above.

Processes for Preparation

[0062] A suitable process for the preparation of the core of the core shell polymer particle of the invention is one that comprises miniemulsion.

[0063] Miniemulsion polymerisation is well known in the art and the term "miniemulsion polymerisation" as used herein means the same as the term known in the art. Numerous scientific reviews of miniemulsion techniques have been published:

1) El Aasser, M.S., Miller, C.M., "Preparation of latexes using miniemulsions", In: Asua, J.M., editor. Polymeric dispersions. Principles and applications. Dordrecht: Kluwer, p. 109-126 (1997)

2) Sudol, E.D., El Aasser, M.S., "Miniemulsion polymerisation", In: Lovell, P.A., El Aasser, M.S., editors. Emulsion polymerisation and emulsion polymers. Chichester: Wiley, p. 699-722 (1997)

3) Asua, J.M., Prog. Polym. Sci., 27, 1283-1346 (2002)

[0064] Miniemulsions generally lie in between macroemulsion and microemulsions in terms of droplet size and emulsion stability. Miniemulsion droplets typically range in size from 50 to 500 nm. The emulsion can be stable for as little as a few days or for as long as a month. The droplets may be stabilised by the addition of an ionic surfactant (e.g. sodium lauryl sulphate) and a cosurfactant. The latter usually consists of either a long chain alkane (e.g. hexadecane) or an alcohol (e.g. hexadecanol). The function of the cosurfactant is twofold; it acts in combination with the surfactant to create a barrier to droplet/droplet coalescence by arranging at the oil-water interface and it also limits diffusion of the oil phase from smaller to larger droplets by virtue of its low water solubility.

[0065] Miniemulsions are typically formed by subjecting an oil (monomer), water, surfactant and cosurfactant system to high shear fields created by devices such as ultrasonifiers, homogenisers and microfluidisers. These devices rely on mechanical shear and/or cavitation to break the oil phase into submicron size droplets. When monomer is used as the oil phase, free radical polymerisation can subsequently be carried out by the addition of an initiator (e.g. ammonium persulphate). Such a process in which the miniemulsion droplets are converted to polymer particles is referred to as miniemulsion polymerisation. For the sake of clarity, by "miniemulsion droplet or emulsion droplet" as used herein is meant the miniemulsion droplet before it is polymerised, and "miniemulsion particles" or "emulsion particles" mean the polymerised miniemulsion droplets.

[0066] In conventional emulsion polymerisation the monomer diffuses through the aqueous phase to the surfactant formed micelles. Particle nucleation begins and proceeds in these micelles and the monomer droplets merely act as a reservoir of monomer. Whereas in miniemulsion polymerisation the presence of cosurfactant and the use of high shear results in the formation of small monomer droplets. These droplets are polymerised directly and no monomer diffusion to micelles occurs and no particle formation occurs within micelles. Such differences are well documented in the literature for example in "Emulsion Polymerisation and Emulsion Polymers", Edited by P.A. Lovell and M.S. El-Aasser, John Wiley and Sons, Chapter 20, page 700-703.

[0067] In conventional emulsion polymerisation, the benefit agent can only be incorporated at relatively low levels (typically 10 % or less by weight of the particle) and must be sparingly water soluble, have low molecular weight (typically under 1,000 g mol^-1) and have similar water solubility and diffusion rate as the monomer. However, for the miniemulsion polymerisation, none of these restraints apply. This allows the incorporation of higher levels (typically from 10 to 90%) and a wider variety of benefit agents, such as completely water insoluble benefit agents (e.g. sugar polyesters, silicone resins and thermoplastic elastomers), in polymer particles, which cannot be achieved using conventional emulsion polymerisation techniques. Furthermore, inorganic particles can also be incorporated into the polymer using miniemulsion, which cannot be achieved using conventional emulsion.

[0068] Preferably, the process comprises the steps of:

(a) preparation of a miniemulsion (comprising monomers, a benefit agent and a cosurfactant), and

(b) polymerisation of the miniemulsion of step (a) to form miniemulsion core particles, and

(c) addition of monomers and subsequent polymerisation to form a shell around the core particles of step (b),

wherein optional attachment of a deposition aid to the polymer particles occurs in step (c).

[0069] Step (a) may consist of the following sub-steps:

(i) monomers and the benefit agent are mixed with a cosurfactant to form a mixture (y),

(ii) a surfactant is dissolved in water to form a mixture (z),

(iii) (y) and (z) are combined and subjected to high shear to form an emulsion,

(iv) the emulsion of step (iii) is then subjected to further shear (such as sonication or other suitable high pressure homogeniser such as a Microfluidiser or a Manton Gaulin homogeniser) to form a miniemulsion.

[0070] By mixed is meant mixed or dissolved, depending on the physical state of the lubricant.

[0071] Preferably, an initiator is added to the miniemulsion such that polymerisation of the monomers proceeds. The initiator can be added during step (a), for example if an initiator that is soluble in the monomer is used, or in step (b), for example if the initiator is water soluble.

[0072] A preferred process comprises the steps of:

(i) mixing monomers and a benefit agent with a cosurfactant to form a mixture (y),

(ii) dissolving a mixture of surfactants in water to form a mixture (z),

(iii) combining (y) and (z) and subjecting to high shear to form a miniemulsion,

(iv) adding an initiator such that polymerisation proceeds, and

(v) adding monomers, an optional deposition aid and initiators at such a rate so as to polymerise the monomers resulting in a shell around the core (with simultaneous attachment of the optional deposition aid onto the polymer particles).

[0073] Alternatively, the surfactant of step (ii) may be a reactive surfactant, by which is meant that it comprises groups that may participate in the polymerisation and a hydrophilic group. In this case it will be combined with the monomer in step (i).

[0074] The resulting polymer cores preferably have a particle size of less than 1 micron, more preferably of less than 500 nm.

[0075] High shear as used herein is applied using any suitable apparatus such as an ultrasound sonicator, microfluidizer or homogenizer. High shear as used in step (iv) above is defined as shear of sufficiently high intensity that the emulsion of step (iii) above is reduced in particle size to sub-micron dimensions, preferably under 500 nm. Suitably, the emulsion of step (iv) is formed using a high shear homogeniser at 10,000 to 24,000 rpm for approximately 30 seconds to 5 minutes and then sonified using a probe ultrasound sonicator (at maximum power output) for 10 minutes to generate the miniemulsion. A suitable homogeniser is a Manton Gaulin homogeniser or any other make of high shear homogenizer such as an Ultra Turrax.

Cosurfactants, Initiators and Chain Transfer Agents

[0076] The monomer is mixed with a cosurfactant. Suitable cosurfactants for use in the present invention include hexadecane, cetyl alcohol, lauroyl peroxide, n-dodecyl mercaptan, dodecyl methacrylate, stearyl methacrylate, polystyrene and polymethyl methacrylate. The preferred cosurfactant comprises hexadecane.

[0077] The cosurfactant could be the benefit agent itself, if it is suitably hydrophobic.

[0078] Initiators and chain transfer agents may also be present. Those skilled in the art will recognise that a chemical initiator will generally be required but that there are instances in which alternative forms of initiation will be possible, e.g. ultrasonic initiation or initiation by irradiation.

[0079] The initiator is preferably a chemical or chemicals capable of forming free radicals. Typically, free radicals can be formed either by homolytic scission (i.e. homolysis) of a single bond or by single electron transfer to or from an ion or molecule (e.g. redox reactions).

[0080] Suitably, in context of the invention, homolysis may be achieved by the application of heat (typically in the range of from 50 to 100°C). Some examples of suitable initiators in this class are those possessing peroxide (-O-O-) or azo (-N=N-) groups, such as benzoyl peroxide, t-butyl peroxide, hydrogen peroxide, azobisisobutyronitrile and ammonium persulphate. Homolysis may also be achieved by the action of radiation (usually ultraviolet), in which case it is termed photolysis. Examples are the dissociation of 2,2'-azobis (2-cyanopropane) and the formation of free radicals from benzophenone and benzoin.

[0081] Redox reactions can also be used to generate free radicals. In this case an oxidising agent is paired with a reducing agent which then undergo a redox reaction. Some examples of appropriate pairs in the context of the invention are ammonium persulphate/sodium metabisulphite, cumyl hydroperoxide/ferrous ion and hydrogen peroxide/ascorbic acid.

[0082] Preferred initiators are selected from the following: Homolytic: benzoyl peroxide, t-butyl peroxide, hydrogen peroxide, azobisisobutyronitrile, ammonium persulphate, 2,2'-azobis (cyanopropane), benzophenone, benzoin, Redox: ammonium persulphate/sodium metabisulphite mixture, cumyl hydroperoxide/ferrous ion mixture and/or hydrogen peroxide/asorbic acid mixture. Preferred initiators are ammonium persulphate and hydrogen peroxide/asorbic acid mixture. The preferred level of initiator is in the range of from 0.1 to 5.0 % w/w by weight of monomer, more preferably, the level is in the range of from 1.0 to 3.0 % w/w by weight of monomer.

[0083] Where the benefit agent is SPE, the preferred initiator is ammonium persulphate and the aqueous phase is buffered with sodium bicarbonate.

[0084] Chain transfer agents can optionally be used to reduce the degree of polymerisation and hence the final molecular weight of the polymer. A chain transfer agent contains very labile hydrogen atoms that are easily abstracted by a propagating polymer chain. This terminates the polymerisation of the growing polymer, but generates a new reactive site on the chain transfer agent that can then proceed to initiate further polymerisation of the remaining monomer. Chain transfer agents in the context of the invention typically contain thiol (mercaptan) functionality and can be represented by the general chemical formula RS-H, such as n-dodecyl mercaptan and 2-mercaptoethanol.
Preferred chain transfer agents are monothioglycerol and n-dodecyl mercaptan, used at levels of, preferably from 0 to 5 % w/w based on the weight of the monomer and more preferably at a level of 0.25 % w/w based on the weight of the monomer.

Laundry Treatment Compositions

[0085] The core shell polymer particles of the invention may be incorporated into laundry compositions.

[0086] The core shell polymer particles are typically included in said compositions at levels of from 0.001% to 10%, preferably from 0.005% to 5%, most preferably from 0.01% to 3% by weight of the total composition.

[0087] The active ingredient in the compositions is preferably a surface active agent or a fabric conditioning agent. More than one active ingredient may be included. For some applications a mixture of active ingredients may be used.

[0088] The compositions of the invention may be in any physical form e.g. a solid such as a powder or granules, a tablet, a solid bar, a paste, gel or liquid, especially, an aqueous based liquid. In particular the compositions may be used in laundry compositions, especially in liquid, powder or tablet laundry composition.

[0089] The compositions of the present invention are preferably laundry compositions, especially main wash (fabric washing) compositions or rinse-added softening compositions. The main wash compositions may include a fabric softening agent and the rinse-added fabric softening compositions may include surface-active compounds, particularly non-ionic surface-active compounds.

[0090] The detergent compositions of the invention may contain a surface-active compound (surfactant) which may be chosen from soap and non-soap anionic, cationic, non-ionic, amphoteric and zwitterionic surface-active compounds and mixtures thereof. Many suitable surface-active compounds are available and are fully described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.

[0091] The preferred detergent-active compounds that can be used are soaps and synthetic non-soap anionic, and non-ionic compounds.

[0092] The compositions of the invention may contain linear alkylbenzene sulphonate, particularly linear alkylbenzene sulphonates having an alkyl chain length of from C8 to C15. It is preferred if the level of linear alkylbenzene sulphonate is from 0 wt% to 30 wt%, more preferably from 1 wt% to 25 wt%, most preferably from 2 wt% to 15 wt%, by weight of the total composition.

[0093] The compositions of the invention may contain other anionic surfactants in amounts additional to the percentages quoted above. Suitable anionic surfactants are well-known to those skilled in the art. Examples include primary and secondary alkyl sulphates, particularly C8 to C15 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.

[0094] The compositions of the invention may also contain non-ionic surfactant. Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the C8 to C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C10 to C15 primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide).

[0095] It is preferred if the level of non-ionic surfactant is from 0 wt% to 30 wt%, preferably from 1 wt% to 25 wt%, most preferably from 2 wt% to 15 wt%, by weight of the total composition.

[0096] Any conventional fabric conditioning agent may be used in the compositions of the present invention. The conditioning agents may be cationic or non-ionic. If the fabric conditioning compound is to be employed in a main wash detergent composition the compound will typically be non-ionic. For use in the rinse phase, typically they will be cationic. They may for example be used in amounts from 0.5% to 35%, preferably from 1% to 30% more preferably from 3% to 25% by weight of the composition.

[0097] Suitable cationic fabric softening compounds are substantially water-insoluble quaternary ammonium materials comprising a single alkyl or alkenyl long chain having an average chain length greater than or equal to C20 or, more preferably, compounds comprising a polar head group and two alkyl or alkenyl chains having an average chain length greater than or equal to C14. Preferably the fabric softening compounds have two long chain alkyl or alkenyl chains each having an average chain length greater than or equal to C16. Most preferably at least 50% of the long chain alkyl or alkenyl groups have a chain length of C18 or above. It is preferred if the long chain alkyl or alkenyl groups of the fabric softening compound are predominantly linear.

[0098] Quaternary ammonium compounds having two long-chain aliphatic groups, for example, distearyldimethyl ammonium chloride and di(hardened tallow alkyl) dimethyl ammonium chloride, are widely used in commercially available rinse conditioner compositions. Other examples of these cationic compounds are to be found in "Surfactants Science Series" volume 34 ed. Richmond 1990, volume 37 ed. Rubingh 1991 and volume 53 eds. Cross and Singer 1994, Marcel Dekker Inc. New York".

[0099] Any of the conventional types of such compounds may be used in the compositions of the present invention.

[0100] The fabric softening compounds are preferably compounds that provide excellent softening, and are characterised by a chain melting Lβ to Lα transition temperature greater than 250°C, preferably greater than 350°C, most preferably greater than 450°C. This Lβ to Lα transition can be measured by differential scanning calorimetry as defined in "Handbook of Lipid Bilayers", D Marsh, CRC Press, Boca Raton, Florida, 1990 (pages 137 and 337).

[0101] Substantially water-insoluble fabric softening compounds are defined as fabric softening compounds having a solubility of less than 1 x 10^-3 wt % in demineralised water at 20°C. Preferably the fabric softening compounds have a solubility of less than 1 x 10^-4 wt%, more preferably from less than 1 x 10^-8 to 1 x 10^-6 wt%.

[0102] Especially preferred are cationic fabric softening compounds that are water-insoluble quaternary ammonium materials having two C12-22 alkyl or alkenyl groups connected to the molecule via at least one ester link, preferably two ester links. An especially preferred ester-linked quaternary ammonium material can be represented by the formula:

wherein each R5 group is independently selected from C1-4 alkyl or hydroxyalkyl groups or C2-4 alkenyl groups; each R6 group is independently selected from C8-28 alkyl or alkenyl groups; and wherein R7 is a linear or branched alkylene group of 1 to 5 carbon atoms, T is

and p is 0 or is an integer from 1 to 5.

[0103] Di(tallowoxyloxyethyl) dimethyl ammonium chloride and/or its hardened tallow analogue is an especially preferred compound of this formula.

[0104] A second preferred type of quaternary ammonium material can be represented by the formula:

wherein R5, p and R6 are as defined above.

[0105] A third preferred type of quaternary ammonium material are those derived from triethanolamine (hereinafter referred to as 'TEA quats') as described in for example US 3915867 and represented by formula:

         (TOCH₂CH₂)₃N+(R9)

wherein T is H or (R8-CO-) where R8 group is independently selected from C8-28 alkyl or alkenyl groups and R9 is C1-4 alkyl or hydroxyalkyl groups or C2-4 alkenyl groups. For example N-methyl-N,N,N-triethanolamine ditallowester or dihardened-tallowester quaternary ammonium chloride or methosulphate. Examples of commercially available TEA quats include Rewoquat WE18 and Rewoquat WE20, both partially unsaturated (ex. WITCO), Tetranyl AOT-1, fully saturated (ex. KAO) and Stepantex VP 85, fully saturated (ex. Stepan).

[0106] It is advantageous if the quaternary ammonium material is biologically biodegradable.

[0107] Preferred materials of this class such as 1,2-bis(hardened tallowoyloxy)-3-trimethylammonium propane chloride and their methods of preparation are, for example, described in US 4 137 180 (Lever Brothers Co). Preferably these materials comprise small amounts of the corresponding monoester as described in US 4 137 180, for example, 1-hardened tallowoyloxy-2-hydroxy-3-trimethylammonium propane chloride.

[0108] Other useful cationic softening agents are alkyl pyridinium salts and substituted imidazoline species. Also useful are primary, secondary and tertiary amines and the condensation products of fatty acids with alkylpolyamines.

[0109] The compositions may alternatively or additionally contain water-soluble cationic fabric softeners, as described in GB 2 039 556B (Unilever).

[0110] The compositions may comprise a cationic fabric softening compound and an oil, for example as disclosed in EP-A-0829531.

[0111] The compositions may alternatively or additionally contain nonionic fabric softening agents such as lanolin and derivatives thereof.

[0112] Lecithins and other phospholipids are also suitable softening compounds.

[0113] In fabric softening compositions nonionic stabilising agent may be present. Suitable nonionic stabilising agents may be present such as linear C8 to C22 alcohols alkoxylated with 10 to 20 moles of alkylene oxide, C10 to C20 alcohols, or mixtures thereof. Other stabilising agents include the deflocculating polymers as described in EP 0415698 A2 and EP 0458599 B1.

[0114] Advantageously the nonionic stabilising agent is a linear C8 to C22 alcohol alkoxylated with 10 to 20 moles of alkylene oxide. Preferably, the level of nonionic stabiliser is within the range from 0.1 to 10% by weight, more preferably from 0.5 to 5% by weight, most preferably from 1 to 4% by weight. The mole ratio of the quaternary ammonium compound and/or other cationic softening agent to the nonionic stabilising agent is suitably within the range from 40:1 to about 1:1, preferably within the range from 18:1 to about 3:1.

[0115] The composition can also contain fatty acids, for example C8 to C24 alkyl or alkenyl monocarboxylic acids or polymers thereof. Preferably saturated fatty acids are used, in particular, hardened tallow C16 to C18 fatty acids. Preferably the fatty acid is non-saponified, more preferably the fatty acid is free, for example oleic acid, lauric acid or tallow fatty acid. The level of fatty acid material is preferably more than 0.1% by weight, more preferably more than 0.2% by weight. Concentrated compositions may comprise from 0.5 to 20% by weight of fatty acid, more preferably 1% to 10% by weight. The weight ratio of quaternary ammonium material or other cationic softening agent to fatty acid material is preferably from 10:1 to 1:10.

[0116] It is also possible to include certain mono-alkyl cationic surfactants which can be used in main-wash compositions for fabrics. Cationic surfactants that may be used include quaternary ammonium salts of the general formula R1R2R3R4N+ X- wherein the R groups are long or short hydrocarbon chains, typically alkyl, hydroxyalkyl or ethoxylated alkyl groups, and X is a counter-ion (for example, compounds in which R1 is a C8-C22 alkyl group, preferably a C8-C10 or C12-C14 alkyl group, R2 is a methyl group, and R3 and R4, which may be the same or different, are methyl or hydroxyethyl groups); and cationic esters (for example, choline esters).

[0117] The choice of surface-active compound (surfactant), and the amount present, will depend on the intended use of the detergent composition. In fabric washing compositions, different surfactant systems may be chosen, as is well known to the skilled formulator, for handwashing products and for products intended for use in different types of washing machine.

[0118] The total amount of surfactant present will also depend on the intended end use and may be as high as 60 wt%, for example, in a composition for washing fabrics by hand. In compositions for machine washing of fabrics, an amount of from 5 to 40 wt% is generally appropriate. Typically the compositions will comprise at least 2 wt% surfactant e.g. 2-60%, preferably 15-40% most preferably 25-35%, by weight of the composition.

[0119] Detergent compositions suitable for use in most automatic fabric washing machines generally contain anionic non-soap surfactant, or non-ionic surfactant, or combinations of the two in any suitable ratio, optionally together with soap.

[0120] The compositions of the invention, when used as main wash fabric washing compositions, will generally also contain one or more detergency builders. The total amount of detergency builder in the compositions will typically range from 5 to 80 wt%, preferably from 10 to 60 wt%, by weight of the compositions.

[0121] Inorganic builders that may be present include sodium carbonate, if desired in combination with a crystallisation seed for calcium carbonate, as disclosed in GB 1 437 950 (Unilever); crystalline and amorphous aluminosilicates, for example, zeolites as disclosed in GB 1 473 201 (Henkel), amorphous aluminosilicates as disclosed in GB 1 473 202 (Henkel) and mixed crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250 (Procter & Gamble); and layered silicates as disclosed in EP 164 514B (Hoechst). Inorganic phosphate builders, for example, sodium orthophosphate, pyrophosphate and tripolyphosphate are also suitable for use with this invention.

[0122] The compositions of the invention preferably contain an alkali metal, preferably sodium, aluminosilicate builder. Sodium aluminosilicates may generally be incorporated in amounts of from 10 to 70% by weight (anhydrous basis), preferably from 25 to 50 wt%.

[0123] The alkali metal aluminosilicate may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8-1.5 Na₂O. Al₂O₃. 0.8-6 SiO₂

[0124] 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 Si02 units (in the formula above). Both the amorphous and the crystalline materials can be prepared readily by reaction between sodium silicate and sodium aluminate, as amply described in the literature. Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are described, for example, in GB 1 429 143 (Procter & Gamble). The preferred sodium aluminosilicates of this type are the well-known commercially available zeolites A and X, and mixtures thereof.

[0125] The zeolite may be the commercially available zeolite 4A now widely used in laundry detergent powders. However, according to a preferred embodiment of the invention, the zeolite builder incorporated in the compositions of the invention is maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070A (Unilever). Zeolite MAP is defined as an alkali metal aluminosilicate of the zeolite P type having a silicon to aluminium weight ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, and more preferably within the range of from 0.90 to 1.20.

[0126] Especially preferred is zeolite MAP having a silicon to aluminium weight ratio not exceeding 1.07, more preferably about 1.00. The calcium binding capacity of zeolite MAP is generally at least 150 mg CaO per g of anhydrous material.

[0127] Organic builders that may be present include polycarboxylate polymers such as polyacrylates, acrylic/maleic copolymers, and acrylic phosphinates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-, di and trisuccinates, carboxymethyloxy succinates, carboxymethyloxymalonates, dipicolinates, hydroxyethyliminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts. This list is not intended to be exhaustive.

[0128] Especially preferred organic builders are citrates, suitably used in amounts of from 5 to 30 wt%, preferably from 10 to 25 wt%; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt%, preferably from 1 to 10 wt%.

[0129] Builders, both inorganic and organic, are preferably present in alkali metal salt, especially sodium salt, form.

[0130] Compositions according to the invention may also suitably contain a bleach system. Fabric washing compositions may desirably contain peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, capable of yielding hydrogen peroxide in aqueous solution.

[0131] Suitable peroxy bleach compounds include organic peroxides such as urea peroxide, and inorganic persalts such as the alkali metal perborates, percarbonates, perphosphates, persilicates and persulphates. Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate.

[0132] Especially preferred is sodium percarbonate having a protective coating against destabilisation by moisture. Sodium percarbonate having a protective coating comprising sodium metaborate and sodium silicate is disclosed in GB 2 123 044B (Kao).

[0133] The peroxy bleach compound is suitably present in an amount of from 0.1 to 35 wt%, preferably from 0.5 to 25 wt%. The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. The bleach precursor is suitably present in an amount of from 0.1 to 8 wt%, preferably from 0.5 to 5 wt%.

[0134] Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and pernoanoic acid precursors. Especially preferred bleach precursors suitable for use in the present invention are N,N,N',N',-tetracetyl ethylenediamine (TAED) and sodium nonanoyloxybenzene sulphonate (SNOBS). The novel quaternary ammonium and phosphonium bleach precursors disclosed in US 4 751 015 and US 4 818 426 (Lever Brothers Company) and EP 402 971A (Unilever), and the cationic bleach precursors disclosed in EP 284 292A and EP 303 520A (Kao) are also of interest.

[0135] The bleach system can be either supplemented with or replaced by a peroxyacid. Examples of such peracids can be found in US 4 686 063 and US 5 397 501 (Unilever). A preferred example is the imido peroxycarboxylic class of peracids described in EP A 325 288, EP A 349 940, DE 382 3172 and EP 325 289. A particularly preferred example is phthalimido peroxy caproic acid (PAP). Such peracids are suitably present at 0.1 - 12%, preferably 0.5 - 10%.

[0136] A bleach stabiliser (transition metal sequestrant) may also be present. Suitable bleach stabilisers include ethylenediamine tetra-acetate (EDTA), the polyphosphonates such as Dequest (Trade Mark) and non-phosphate stabilisers such as EDDS (ethylene diamine di-succinic acid). These bleach stabilisers are also useful for stain removal especially in products containing low levels of bleaching species or no bleaching species.

[0137] An especially preferred bleach system comprises a peroxy bleach compound (preferably sodium percarbonate optionally together with a bleach activator), and a transition metal bleach catalyst as described and claimed in EP 458 397A, EP 458 398A and EP 509 787A (Unilever).

[0138] The compositions according to the invention may also contain one or more enzyme(s).

[0139] Suitable enzymes include the proteases, amylases, cellulases, oxidases, peroxidases and lipases usable for incorporation in detergent compositions. Preferred proteolytic enzymes (proteases) are, catalytically active protein materials which degrade or alter protein types of stains when present as in fabric stains in a hydrolysis reaction. They may be of any suitable origin, such as vegetable, animal, bacterial or yeast origin.

[0140] Proteolytic enzymes or proteases of various qualities and origins and having activity in various pH ranges of from 4-12 are available and can be used in the instant invention. Examples of suitable proteolytic enzymes are the subtilisins which are obtained from particular strains of B. Subtilis B. licheniformis, such as the commercially available subtilisins Maxatase (Trade Mark), as supplied by Genencor International N.V., Delft, Holland, and Alcalase (Trade Mark), as supplied by Novozymes Industri A/S, Copenhagen, Denmark.

[0141] Particularly suitable is a protease obtained from a strain of Bacillus having maximum activity throughout the pH range of 8-12, being commercially available, e.g. from Novozymes Industri A/S under the registered trade-names Esperase (Trade Mark) and Savinase (Trade-Mark). The preparation of these and analogous enzymes is described in GB 1 243 785. Other commercial proteases are Kazusase (Trade Mark obtainable from Showa-Denko of Japan), Optimase (Trade Mark from Miles Kali-Chemie, Hannover, West Germany), and Superase (Trade Mark obtainable from Pfizer of U.S.A.).

[0142] Detergency enzymes are commonly employed in granular form in amounts of from about 0.1 to about 3.0 wt%. However, any suitable physical form of enzyme may be used. The compositions of the invention may contain alkali metal, preferably sodium carbonate, in order to increase detergency and ease processing. Sodium carbonate may suitably be present in amounts ranging from 1 to 60 wt%, preferably from 2 to 40 wt%. However, compositions containing little or no sodium carbonate are also within the scope of the invention.

[0143] Powder flow may be improved by the incorporation of a small amount of a powder structurant, for example, a fatty acid (or fatty acid soap), a sugar, an acrylate or acrylate/maleate copolymer, or sodium silicate. One preferred powder structurant is fatty acid soap, suitably present in an amount of from 1 to 5 wt%.

[0144] Other materials that may be present in detergent compositions of the invention include sodium silicate; antiredeposition agents such as cellulosic polymers; soil release polymers; inorganic salts such as sodium sulphate; or lather boosters as appropriate; proteolytic and lipolytic enzymes; dyes; coloured speckles; fluorescers and decoupling polymers. This list is not intended to be exhaustive. However, many of these ingredients will be better delivered as benefit agent groups in materials produced according to the first aspect of the invention.

[0145] The detergent composition when diluted in the wash liquor (during a typical wash cycle) will typically give a pH of the wash liquor from 7 to 10.5 for a main wash detergent.

[0146] Particulate detergent compositions are suitably prepared by spray-drying a slurry of compatible heat-insensitive ingredients, and then spraying on or post-dosing those ingredients unsuitable for processing via the slurry. The skilled detergent formulator will have no difficulty in deciding which ingredients should be included in the slurry and which should not.

[0147] Particulate detergent compositions of the invention preferably have a bulk density of at least 400 g/litre, more preferably at least 500 g/litre. Especially preferred compositions have bulk densities of at least 650 g/litre, more preferably at least 700 g/litre.

[0148] Such powders may be prepared either by post-tower densification of spray-dried powder, or by wholly non-tower methods such as dry mixing and granulation; in both cases a high-speed mixer/granulator may advantageously be used.

[0149] Processes using high-speed mixer/granulators are disclosed, for example, in EP 340 013A, EP 367 339A, EP 390 251A and EP 420 317A (Unilever).

[0150] Liquid detergent compositions can be prepared by admixing the essential and optional ingredients thereof in any desired order to provide compositions containing components in the requisite concentrations. Liquid compositions according to the present invention can also be in compact form which means it will contain a lower level of water compared to a conventional liquid detergent.

Product Forms

[0151] Product forms include powders, liquids, gels, tablets, any of which are optionally incorporated in a water-soluble or water dispersible sachet. The means for manufacturing any of the product forms are well known in the art. If the core shell polymer particles are to be incorporated in a powder (optionally the powder to be tableted), and whether or not pre-emulsified, they are optionally included in a separate granular component, e.g. also containing a water soluble organic or inorganic material, or in encapsulated form.

Substrate

[0152] When used in laundering, the substrate may be any substrate onto which it is desirable to deposit polymer particles and which is subjected to treatment such as a washing or rinsing process.

[0153] In particular, the substrate may be a textile fabric. It has been found that particularly good results are achieved when using a natural fabric substrate such as cotton, or fabric blends containing cotton.

Treatment

[0154] The treatment of the substrate with the material of the invention can be made by any suitable method such as washing, soaking or rinsing of the substrate.

[0155] Typically the treatment will involve a washing or rinsing method such as treatment in the main wash or rinse cycle of a washing machine and involves contacting the substrate with an aqueous medium comprising the material of the invention.

Examples

[0156] The present invention will now be explained in more detail by reference to the following non-limiting examples:-

[0157] In the following examples where percentages are mentioned, this is to be understood as percentage by weight.

[0158] The following abbreviations are used:

SPE -

sugar polyester, the type used in these examples was

ER290 -

ex. Mitsubishi Ryoto (sucrose tetraerucate)

LBG -

locust bean gum

THF -

Tetrahydrofuran

PBMA -

Polybutylmethacrylate

PVAc -

PolyvinylAcetate

Example 1 - Preparation of an aqueous suspension of core shell particles, D12 (core = SPE + PBMA, shell = PVAc, deposition aid = LBG)

[0159] 

1. Synperonic A20 (1.0 g) and Sodium Dodecyl Sulphate (0.25 g) were dissolved in water (425 g) to produce Solution A.

2. Butyl methacrylate (25.0 g), SPE (25.0 g) and hexadecane (2.0 g) were mixed together with stirring (Solution B).

3. Solution A was stirred with an Ultratorax mixer at 22,000 rpm and solution B was added slowly over 1 minute. The mixture was stirred for a further 5 minutes. The resulting mixture was then sonicated for 10 minutes at full power to form a pre-emulsion.

4. The pre-emulsion was placed in a suitable vessel for emulsion polymerisation fitted with a condenser and an over head stirrer and placed in a thermostatically controlled oil bath and heated to 75°C. Sodium bicarbonate (0.5 g) in water (10 ml) and ammonium persulphate (0.5 g) in water (10 ml) were then added.

5. After 2.5 hours, vinyl acetate (25 g) and LBG (1 g) in water (50 ml) were added, and the mixture stirred for 30 minutes. To the pre-emulsion was then added an initiator (33% hydrogen peroxide (0.77 g) in water (5 ml) added followed by ascorbic acid (0.25 g) in water (5 ml)).

6. The reaction mixture was allowed to cool down after a further 2.5 hours and Tween 80 (2 g) in water (10 ml) was added. An aqueous suspension of ca. 10 % by weight of core shell particles D12 resulted.

[0160] Using this basic method, various control particles were prepared according to Table 1.

[0161] To prepare control particles A1, butyl methacrylate was omitted from solution B and steps 5 and 6 were omitted.
To prepare control particles A12, butyl methacrylate was omitted from solution B.

[0162] To prepare control particles B1, toluene was substituted for the butyl methacrylate and steps 5 and 6 were omitted.
To prepare control particles B12, toluene was substituted for the butyl methacrylate.

[0163] To prepare control particles D1, steps 5 and 6 were omitted.

Table 1 - Composition of Particles

Particle	Core composition		shell composition	Deposition Aid
	SPE	polymer
A1	SPE	-	-	-
A12	SPE	-	PVAc	LBG
B1	SPE	toluene	-	-
B12	SPE	toluene	PVAc	LBG
D1	SPE	BMA	-	-
D12	SPE	BMA	PVAc	LBG

[0164] D12 is a particle in accordance with the invention.

Example 2 - Protection of Benefit Agent Deposited on Fabric

[0165] The amount of benefit agent deposited onto fabric was determined as follows:-

[0166] 50 microlitres of the 10 % by weight aqueous suspension of the particles were spotted onto fabric (cotton sheeting). 50 microlitres of the same suspension was placed into a glass vial as a control (C1). The fabric was washed at 40 °C in a front loading automatic washing machine before being line dried, then cut up into small pieces and placed in a second glass vial. THF (10 ml) was added to both glass vials, which were then left for 16 hours to fully dissolve the polymer and SPE. The level of SPE and polymer thus extracted into the THF were quantified using GPC (using a Plgel 100Δ column).

Table 2 - Amount (%) of SPE Remaining on the Fabric After Washing

Particle	% SPE
A1	8.1
A12	0
B1	0
B12	0
D1	23.9
D12	28.4

[0167] It will be seen that the particle according to the invention (D12) gives greater protection of SPE deposited on the fabric against surfactants than all the control particles.

Example 3 - Other particle compositions and performance

[0168] The following compositions were prepared as per the aforementioned method, using 25g of monomer (or 12.5g each of the 50:50 mix). The performance of the particles as regards the benefit of retention of the SPE was also ascertained. the method used was the same as for example 2.

Particle	Core Composition		Shell composition	Deposition Aid	% SPE remaining on the fabric after washing
	SPE	Polymer
E1	SPE	-	-	-	0
F1	SPE	BMA	PVAc	LBG	52.1
G1	SPE	BMA/SMA 50:50	PVAc	LBG	76.0
H1	SPE	LMA	PVAc	LBG	74.4
I1	SPE	SMA	PVAc	LBG	64.2
J1	SPE	BA	PVAc	LBG	57.9
K1	SPE	HA	PVAc	LBG	73.2
L1	SPE	LA	PVAc	LBG	49.4

[0169] The following abbreviations were used:

SPE -

sugar polyester, the type used in these examples was ER290 - ex. Mitsubishi Ryoto (sucrose tetraerucate)

LBG -

locust bean gum

BMA -

butylmethacrylate

SMA -

stearylmethacrylate

LMA -

laurylmethacrylate

BA -

butylacrylate

HA -

hexylacrylate

LA -

laurylacrylate

PVAc -

PolyvinylAcetate

Claims

1. A polymer particle comprising a core and a shell,
wherein the core comprises a benefit agent which is a lubricant and a polymer comprising monomer units which contain at least one ethylenically unsaturated group capable of undergoing addition polymerisation and are derived from monomers selected from the group consisting of:-

a) monomers with a solubility in water of less than 0.1 g/l, and/or

b) monomers with a solubility in water of from 0.1 to 30 g/l, and

c) optionally, monomers with a solubility in water of greater than 30 g/l, and/or

d) optionally, cross linkers, and

wherein the shell comprises monomer units selected from b), and optionally c) and/or optionally d).

2. A particle as claimed in claim 1, wherein the benefit agent is selected from a silicone, mineral oil, vegetable oil and sugar polyester.

3. A particle as claimed in claim 1 or claim 2, wherein the benefit agent comprises a biodegradable lubricant.

4. A particle as claimed in claim 3 wherein the lubricant is a sugar polyester.

5. A particle as claimed in claim 4 wherein the sugar polyester is a sucrose polyester, preferably selected from sucrose tetrastearate, sucrose tetraerucate, sucrose tetralaurate, sucrose tetraoleate, sucrose tetrapalmitate and sucrose tetrapalm kernal.

6. A particle as claimed in claim 4 wherein the core comprises from 0.1 to 99 %, preferably from 50 to 99 % of sugar polyester, by weight.

7. A particle as claimed in claim 1 wherein the core and/or the shell comprise monomer units which are derived from monomers selected from the group consisting of olefins, ethylene, vinylaromatic monomers, esters of vinyl alcohol with mono- and dicarboxylic acids, esters of α,β-monoethylenically unsaturated mono- and dicarboxylic acids with alcohols, nitriles of α,β-monoethylenically unsaturated carboxylic acids, conjugated dienes, α,β-monoethylenically unsaturated monocarboxylic and dicarboxylic acids and their amides, methacrylic acid and its esters with alcohols and diols, acrylic acid and its esters with alcohols and diols, dimethyl or din-butyl maleate, and/or vinyl-sulfonic acid and its water-soluble salts and mixtures thereof.

8. A particle as claimed in claim 1 wherein the monomers a), b), c) and d) comprise the following:-

a) vinyl octate; Vinyl decanote, vinyl laurate; vinyl stearate; esters of acrylic, methacrylic, maleic, fumaric or itaconic acid with decyl, dodecyl, tetadecyl, hexadecyl and octadecyl alcohol,

b) styrene; α-methylstyrene; o-chlorostyrene vinyl acetate; vinyl propionate; vinyl n-butyrate; esters of acrylic, methacrylic, maleic, fumaric or itaconic acid with methyl, ethyl, n-butyl, isobutyl, n-hexyl and 2-ethylhexyl alcohol; 1,3-butadiene; 2,3 dimethyl butadiene; and isoprene,

c) acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, poly (alkylene oxide) monoacrylates and monomethacrylates, N-vinyl-pyrrolidone, methacrylic and acrylic acid, 2-hydroxyethyl acrylates and methacrylates, glycerol acrylates and methacrylates, poly(ethylene glycol) methacrylates and acrylates, n-vinyl pyrrolidone, acryloyl morpholine, vinyl formamide, n-vinyl acetamide and vinyl caprolactone, acrylonitrile (71 g/l), acrylamide, and methacrylamide at levels of less than 10 % by weight of the monomer unit content of the particle; 2-(dimethylamino) ethyl methacrylate, 2-(diethylamino) ethyl methacrylate, 2-(tert-butylamino) ethyl methacrylate, 2 - aminoethyl methacrylate, 2-(2-oxo-1-imidazolidinyl) ethyl methacrylate, vinyl pyridine, vinyl carbazole, vinyl imidazole, vinyl aniline, and their cationic forms after treatment with alkyl halides,

d) vinyltoluenes, divinyl benzene, ethylene glycol diacrylate, 1,2-propylene glycol diacrylate, 1,3-propylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylates, ethylene glycol dimethacrylate, 1,2-propylene glycol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, divinylbenzene, vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, methylenebisacrylamide, cyclopentadienyl acrylate, and triallyl cyanurate.

9. A particle as claimed in claim 1 wherein the core comprises monomer units, which are derived from monomers selected from the group consisting of butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate, dodecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, styrene, vinyl acetate and divinyl benzene, or mixtures thereof.

10. A particle as claimed in claim 1, having a particle size of less than 1 micron, preferably of less than 500 nm.

11. A particle as claimed in claim 1 which further comprises a deposition aid.

12. A particle as claimed in claim 11, wherein the deposition aid is nonionic.

13. A particle as claimed in claim 12, wherein the deposition aid is a polysaccharide having β-1,4 linkages.

14. A particle as claimed in claim 13, wherein the polysaccharide is selected from the group consisting of a polymannan, a polyglucan, a polyglucomannan, a polyxyloglucan and a polygalactomannan or a mixture thereof.

15. A particle as claimed in claim 14, wherein the polysaccharide is locust bean gum.

16. A particle as claimed in claim 11, wherein the deposition aid is cationic.

17. A particle as claimed in claim 16, wherein the deposition aid is a polysaccharide.

18. A particle as claimed in claim 17, wherein the polysaccharide comprises β-1,4 linkages.

19. A particle as claimed in claim 18, wherein the polysaccharide is selected from the group consisting of cationically modified polymannan, a polyglucan, a polyglucomannan, a polyxyloglucan and a polygalactomannan or a mixture thereof.

20. A particle as claimed in claim 19, wherein the polysaccharide is a cationically modified cellulose or guar.

21. A process for the preparation of polymer particles as claimed in claim 1, wherein the process for preparation of the core comprises miniemulsion polymerisation of monomers.

22. A process as claimed in claim 21 which comprises the steps of:

(a) preparation of a miniemulsion (comprising monomers, a benefit agent and a cosurfactant), and

(b) polymerisation of the miniemulsion of step (a) to form miniemulsion core particles, and

(c) addition of monomers and subsequent polymerisation to form a shell around the core particles of step (b),

wherein optional attachment of a deposition aid to the polymer particles occurs in step (c).

23. A process as claimed in claim 22 which comprises the steps of:

(i) mixing monomers and a benefit agent with a cosurfactant to form a mixture (y),

(ii) dissolving a mixture of surfactants in water to form a mixture (z),

(iii) combining (y) and (z) and subjecting to high shear to form a miniemulsion,

(iv) adding an initiator such that polymerisation proceeds, and

(v) adding monomers, an optional deposition aid and initiators at such a rate so as to polymerise the monomers resulting in a shell around the core (with simultaneous attachment of the optional deposition aid onto the polymer particles).

24. A laundry treatment composition comprising the particle as claimed in any of claims 1 to 20.

25. Use of a laundry treatment composition as claimed in claim 24 in the treatment of fabric.

26. Use as claimed in claim 25 wherein the use provides a protection benefit to the benefit agent from surfactants during a laundry process.

27. A method of treating fabric, comprising contacting the fabric with the polymer particle according to any one of claims 16 to 20.

28. A method of treating fabric, preferably cotton, comprising contacting the fabric with the polymer particle according to any one of claims 12 to 15.

29. Use of a particle as claimed in claims 1 to 20 in the treatment of a fabric to provide a protection benefit to the benefit agent from surfactants during a laundry process.

30. Use of a particle as claimed in claims 12 to 15 in the treatment of cotton, to provide a protection benefit to the benefit agent from surfactants during a laundry process.