EP2089150A1

EP2089150A1 - Microcapsules

Info

Publication number: EP2089150A1
Application number: EP07821417A
Authority: EP
Inventors: Marc Rudolf Jung; Dieter Niederberger; Hans Willax; Hans-Peter Hentze
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-10-17
Filing date: 2007-10-17
Publication date: 2009-08-19
Also published as: US20120177924A1; US8163207B2; JP5517623B2; CN101528339A; WO2008046839A1; JP2010506988A; US20090289216A1; CN101528339B

Abstract

The invention relates to microcapsules comprising a capsule core, a capsule wall and polyelectrolytes that are arranged on the outer surface of the capsule wall, said polyelectrolytes having an average molecular weight of 500 g/mol to 10 million g/mol. Said capsule wall is made of between 10 and 100% by wt. of one or more C1-C24-alkyl esters of acrylic acid and/or methacrylic acid (monomers I), between 0 and 80 % by wt. of a bifunctional or polyfunctional monomer (monomers II) which is not soluble or poorly soluble in water and between 0 to 90% by wt of other monomers (monomers III), each percentage being in relation to the total weight of the monomers. Said microcapsules have an average particle size of between 1.5 - 2.5 µm and 90 % of the particles have a particle size of ≤4 µm. The invention also relates to a method for producing said microcapsules, to its use in textiles, binding agents and heat transfer liquids and microcapsules as an intermediate product.

Description

microcapsules

description

The present invention relates to microcapsules comprising a capsule core, a capsule wall and disposed on the outer surface of the capsule wall polyelectrolytes having an average molecular weight of 500 g / mol to 10 million g / mol, wherein the capsule wall is constructed

10 to 100% by weight of one or more C 1 -C 24 -alkyl esters of acrylic and / or methacrylic acid (monomers I), 0 to 80% by weight of a bi- or polyfunctional monomer (monomers II) which is dissolved in water is insoluble or sparingly soluble and 0 to 90% by weight of other monomers (monomer III)

each based on the total weight of the monomers, wherein the microcapsules have an average particle size of 1, 5 - 2.5 microns and 90% of the particles have a particle size <4 microns.

Moreover, the present invention relates to a process for their preparation, their use in textiles, binders and heat transfer fluids and microcapsules as an intermediate.

In recent years textiles with latent heat stores have been investigated as a new combination of materials. The mode of operation of the latent heat storage, often also referred to as PCM (phase change material), is based on the transformation enthalpy occurring during the solid / liquid phase transition, which means an energy absorption or the release of energy to the environment. They can thus be used for temperature maintenance in a defined temperature range.

EP 1 029 018 teaches the use of microcapsules having a capsule wall of a highly crosslinked methacrylic acid ester polymer and a latent heat storage core in bonding building materials such as concrete or gypsum. DE-A-101 39 171 describes the use of microencapsulated latent heat storage materials in plasterboard. Furthermore, WO 2005/1 16559 teaches the use of microencapsulated latent heat storage materials in chipboard together with melamine-formaldehyde resins as binders. In the construction sector, it is often advantageous to use larger microcapsules, since they are usually less dusty or can be processed more advantageously with other additives. Other requirements, however, the textile sector. Microcapsules which are to be spun together with the fiber mass must be sufficiently small so that the fibers do not become brittle and can be processed in the spinning process. The microcapsule powder taught in EP-A-1 029 018, WO 2005/1 16559, and DE-A-101 39 171 has mean particle sizes in the range from 2 to 25 μm. The size of the powder particles corresponds to the capsule sizes in the microcapsule dispersions.

EP-A 1 321 182 teaches microencapsulated latent heat storage materials with a capsule wall of a highly crosslinked methacrylic acid ester polymer and also mentions their use in textiles. Teaching this document are microcapsule dispersions with a particularly low proportion of capsules of particle size <4 microns.

EP-A 1 251 954 teaches polymethacrylic acid-based microcapsules with particle sizes of 1.2 μm for the impregnation of fibers. Small capsules, however, often show inadequate seals, especially with respect to detergents.

The older European application no. No. 061 17092.4 teaches polyelectrolyte-modified microcapsules with average particle sizes of 4.7 μm and larger, which show improved chemical cleaning resistance in the textile sector.

It was therefore an aspect of the present invention to find microcapsules with latent heat storage materials as capsule core, which can be incorporated in the manufacture of textile fibers.

Accordingly, the abovementioned microcapsules have been found, a process for their preparation and their use in textiles, binders and heat transfer fluids. Furthermore, microcapsules were found as an intermediate, a process for their preparation and their use.

The microcapsules according to the invention comprise a capsule core and a capsule wall. The capsule core consists predominantly, to more than 95 wt .-%, of lipophilic substance. The average particle size of the capsules (Z means by means of light scattering) is 1.5 to 2.5 μm, preferably 1.7 to 2.4 μm. According to the invention, 90% of the particles have a particle size (diameter) <4 μm, preferably <3.5 μm, in particular <3 μm. The average half-width of the microcapsule distribution is 0.2 to 1.5 μm, preferably 0.4 to 1 μm. The weight ratio of capsule core to capsule wall is generally from 50:50 to 95: 5. Preferred is a core / wall ratio of 70:30 to 93: 7.

According to the invention, polyelectrolytes are arranged on the outer surface of the capsule wall. Depending on the amount of polyelectrolyte, it is a point arrangement of the polyelectrolyte to Polyelektrolytbereiche on the surface up to a uniform arrangement of the polyelectrolyte, which resembles a layer or shell.

In general, the proportion of the polyelectrolyte is 0.1 to 10 wt .-% based on the total weight of the polyelectrolyte-carrying microcapsules. The proportion of polyelectrolyte is preferably 0.5-5% by weight, in particular 1-3% by weight, based on the total weight of the polyelectrolyte-carrying microcapsules.

Depending on the field of application, different wall thicknesses may be required, so that it may also be useful to orient the amount of polyelectrolyte to the total amount of the monomers of the wall.

Thus, the amount of polyelectrolyte preferred according to one embodiment is from 10 to 30% by weight, based on the total amount of monomers of the wall material.

In another embodiment, the preferred amount of polyelectrolyte is 5 to 15% by weight, based on the total amount of monomers of the wall material.

Polyelectrolytes generally refer to polymers having ionizable or ionically dissociable groups which may be constituents or substituents of the polymer chain. Usually, the number of these ionizable or ionically dissociable groups in the polyelectrolyte is so great that the polymers in the ionic form (also called polyions) are water-soluble or swellable in water. Po are preferably lyelektrolyte, which have a solubility of> 4 g / l in water at 25 ⁰ C, par- polyelectrolytes with unlimited solubility in water. Preferred are polyelectrolytes which carry an electrolyte functionality at each repeat unit.

In contrast to protective colloids, polyelectrolytes generally have little or no emulsifying action and often have a thickening effect. In the context of the present invention, polyelectrolytes have an average molecular weight of 500 to 10 000 000 g / mol, preferably 1000 to 100 000 g / mol, in particular 1 000 to 10 000 g / mol. It can be used linear or branched polyelectrolytes. Unlike the protective colloids used in the context of the present invention, which are added prior to the polymerization to prepare the oil-in-water emulsion, polyelectrolytes in the context of the present invention are polymers having ionizable or ionically dissociable groups with the microcapsules after polymerization - in aqueous medium, preferably water, are brought into contact. By aqueous medium are meant aqueous mixtures containing up to 10 wt .-% based on the aqueous medium, a water-miscible solvent which is miscible in the desired amount at 25 ° C and 1 bar with water. These include alcohols such as methanol, ethanol, propanol, isopropanol, glycol, glycerol and methoxyethanol and water-soluble ethers such as tetrahydrofuran and dioxane and aprotic additives such as dimethylformamide or dimethylsulfoxide.

Depending on the nature of the dissociable groups, a distinction is made between cationic and anionic polyelectrolytes (also referred to as polyions). Considered is the charge of the polyion (without counterion). Cationic polyelectrolytes arise from basic group-containing polymers (polybases) by addition of protons or quaternization.

Anionic polyelectrolytes are formed from polymers containing acidic groups (polyacids) by elimination of protons.

The assignment of the polyelectrolyte is carried out according to the resulting total charge of the polyion (ie without counterion). If the polyelectrolyte has predominantly positively charged, dissociated groups, then it is a cationic polyelectrolyte. On the other hand, if it has predominantly negatively charged groups, then it is an anionic polyelectrolyte. One or more cationic or one or more anionic polyelectrolytes are preferably used. Particular preference is given to choosing one or more cationic polyelectrolytes. It is assumed that the successive addition of a plurality of differently charged polyelectrolytes leads to the formation of several layers, provided that the amount of polyelectrolyte is sufficient in each case for the construction of a layer. As a rule, a polyelectrolyte amount of at least 1% by weight of polyelectrolyte, based on the total weight of the polyelectrolyte-carrying microcapsules, leads to a coating. Preferably, however, only one polyelectrolyte layer is applied. This layer may be one or a mixture of several like charged polyelectrolytes.

Anionic polyelectrolytes are obtainable, for example, by free-radical polymerization of ethylenically unsaturated anionic monomers in an aqueous medium. Examples of ethylenically unsaturated anionic monomers are mono- ethylenically unsaturated C3- to C5-carboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid, sulfonic acids such as vinylsulfonic acid, styrenesulfonic acid and acrylamidomethylpropanesulfonic acid and phosphonic acids such as vinylphosphonic acid, and / or in each case the alkali metal, alkaline earth metal and / or ammonium salts of these acids into consideration.

Preferred anionic monomers include acrylic acid, methacrylic acid, maleic acid and acrylamido-2-methylpropanesulfonic acid. Particularly preferred are aqueous dispersions of polymers based on acrylic acid. The anionic monomers can be polymerized either alone to form homopolymers or else mixed with one another to give copolymers. Examples include the homopolymers of acrylic acid, homopolymers of methacrylic acid or copolymers of acrylic acid and maleic acid, copolymers of acrylic acid and methacrylic acid and copolymers of methacrylic acid and maleic acid.

However, the polymerization of the anionic monomers can also be carried out in the presence of at least one other ethylenically unsaturated monomer. These monomers may be nonionic or may carry a cationic charge.

Examples of nonionic comonomers are acrylamide, methacrylamide, N-Cr to C3-alkylacrylamides, N-vinylformamide, acrylic esters of monohydric alcohols having from 1 to 20 carbon atoms, in particular methyl acrylate, ethyl acrylate, isobutyl acrylate and n- Butyl acrylate, methacrylic acid esters of monohydric alcohols having 1 to 20 carbon atoms z. For example, methyl methacrylate and ethyl methacrylate, and vinyl acetate and vinyl propionate.

Suitable cationic monomers which can be copolymerized with the anionic monomers are dialkylaminoethyl acrylates, dialkylaminoethyl methacrylates, dialkylaminopropyl acrylates, dialkylaminopropyl methacrylates, dialkylaminoethylacrylamides, dialkylaminoethylmethacrylamides, dialkylaminopropylacrylamides, dialkylaminopropylmethacrylamides, diallyldimethylammonium chloride, vinylimidazole and the cationic monomers neutralized and / or quaternized with mineral acids , Specific examples of cationic monomers are dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethyaminopropyl acrylate, dimethylaminopropyl methacrylate, diethylaminopropyl acrylate and diethylaminopropyl methacrylate, dimethylaminoethylacrylamide, dimethylaminoethylmethacrylamide, dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide, diethylaminoethylacrylamide and diethylaminopropylacrylamide.

The cationic monomers may be completely or even partially neutralized or quaternized, for. B. in each case to 1 to 99%. Preferred quaternizing agent for the cationic monomers is dimethylsulfate. However, the quaternization of the monomers can also be carried out with diethyl sulfate or with alkylating agents, in particular alkyl halides such as methyl chloride, ethyl chloride or benzyl chloride. The comonomers are used in the preparation of the anionic polyelectrolytes, for example, in amounts such that the resulting polymer dispersions when diluted with water and at pH values above 7.0 and a temperature of 20 ⁰ C are water-soluble and have an anionic charge. Based on the total monomers used in the polymerization, the amount of nonionic and / or cationic comonomers z. B. 0 to 99, preferably 5 to 75 wt .-% and is usually in the range of 5 to 25 wt .-%. The cationic monomers are used at most in an amount such that the entste- Henden polyelectrolytes <6.0 and a temperature of 20 ⁰ C carry a total anionic charge at pH values. The anionic excess charge in the resulting amphoteric polymers is z. B. at least 5 mol%, preferably at least 10 mol%, in particular at least 30 mol%, very particularly preferably at least 50 mol%. Examples of preferred copolymers are copolymers of 25 to 90% by weight of acrylic acid and 75 to 10% by weight of acrylamide. Preferably, at least one ethylenically unsaturated C3 to C5 carboxylic acid is polymerized in the absence of other monoethylenically unsaturated monomers. Particular preference is given to homopolymers of acrylic acid obtainable by free-radical polymerization of acrylic acid in the absence of other monomers.

As crosslinkers for the preparation of branched polyelectrolytes, it is possible to use all compounds which have at least two ethylenically unsaturated double bonds in the molecule. Such compounds are used, for example, in the preparation of crosslinked polyacrylic acids such as superabsorbent polymers, cf. EP-A 0 858 478, page 4, line 30 to page 5, line 43. Examples of crosslinkers are triallylamine, pentaerythritol triallether, pentaerythritol tetraallyl ether, methylenebisacrylamide, N, N'-divinylethyleneurea, at least two allyl-containing allyl ethers or at least two vinyl-containing vinyl ethers of polyhydric alcohols such. B. sorbitol, 1, 2-ethanediol, 1, 4-butanediol, trimethylolpropane, glycerol, diethylene glycol and of sugars such as sucrose, glucose, mannose, completely with acrylic acid or methacrylic acid esterified dihydric alcohols having 2 to 4 carbon atoms such as ethylene glycol dimethacrylate , Ethylene glycol diacrylate, butanediol dimethacrylate, butanediol diacrylate, diacrylates or dimethacrylates of polyethylene glycols having molecular weights of 300 to 600, ethoxylated trimethylenepropane triacrylates or ethoxylated trimethylene propane trimethacrylates, 2,2-bis (hydroxymethyl) butanol trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate and triallylmethylammonium chloride. If crosslinking agents are used in the preparation of the dispersions according to the invention, the amounts of crosslinker used in each case are, for example, 0.0005 to 5.0, preferably 0.001 to 1.0,% by weight, based on the total monomers used in the polymerization. Preferred crosslinkers are pentaerythritol triallyl ether, pentaerythritol tetraallyl ether, N, ^{N'-divinylethyleneurea,} at least two allyl groups-containing allyl ethers of sugars such as sucrose, glucose or mannose, and triallylamine and mixtures of these compounds.

As anionic polyelectrolytes it is also possible to use polycondensates, for example phenolsulfonic acid resins. Suitable are aldehyde condensates, especially based on formaldehyde, acetaldehyde, isobutyraldehyde, propionaldehyde, glutaraldehyde and glyoxal, especially formaldehyde condensates based on phenolsulfonic acids. As further reacting compounds, for example Amines or amides, in particular those of carbonic acid such as urea, melamine or dicyandiamide for the production of Phenolsulfonsäureharze be used.

The phenolsulfonic acid resins are preferably present as salts. The condensation products of the invention preferably have a degree of condensation of from 1 to 20 and an average molecular weight of from 500 to 10,000 g / mol. The phenolsulfonic acid resins are preferably prepared analogously to the manner specified in EP-A 816 406.

Examples of cationic polyelectrolytes are polymers from the group of

(a) polymers containing vinylimidazolium units,

(b) polydiallyldimethylammonium halides, (c) polymers containing vinylamine units,

(d) polymers containing ethyleneimine units,

(e) polymers containing dialkylaminoalkyl acrylate and / or dialkylaminoalkyl methacrylate units, and

(f) polymers containing dialkylaminoalkylacrylamide and / or dialkylaminoalkylmethacrylamide units

into consideration. Such polymers are known and commercially available. The monomers underlying the cationic polyelectrolytes of groups a-f can be used in the form of the free base, but preferably in the form of their salts with mineral acids such as hydrochloric acid, sulfuric acid or phosphoric acid and in quaternized form for the polymerization. Suitable quaternizing agents are, for example, dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride, cetyl chloride or benzyl chloride.

Examples of cationic polyelectrolytes are

(a) homopolymers of vinylimidazolium methosulfate and / or copolymers of vinylimidazolium methosulfate and N-vinylpyrrolidone,

(b) polydiallyldimethylammonium chlorides, (c) polyvinylamines and partially hydrolyzed polyvinylformamides, (d) polyethylenimines (e) polydimethylaminoethyl acrylate, polydimethylaminoethyl methacrylate, copolymers of acrylamide and dimethylaminoethyl acrylate and copolymers of acrylamide and dimethylaminoethyl methacrylate, where the basic monomers may also be present in the form of the salts with mineral acids or in quaternized form, and

(F) polydimethylaminoethylacrylamide, polydimethylaminoethylmethacrylamide and copolymers of acrylamide and dimethylaminoethylacrylamide, wherein the cationic monomers may also be present in the form of the salts with mineral acids or in quaternized form.

The average molecular weights M _{w of} the cationic polyelectrolytes are at least 500 g / mol. They are, for example, in the range of 500 g / mol to 10 million g / mol, preferably in the range of 1,000 to 500,000 g / mol and most often 1,000 to 5,000 g / mol.

Preferably used as cationic polymers

(a) homopolymers of vinylimidazolium methosulfate and / or copolymers of vinylimidazolium methosulfate and N-vinylpyrrolidone having an average molar mass M _w of in each case 500 to 10,000 g / mol,

(b) polydiallyldimethylammonium chlorides having an average molecular weight M _{w of} from 1000 to 10 000 g / mol,

(c) polyvinylamines and partially hydrolyzed polyvinylformamides having an average molecular weight Mw of 500 to 10,000 g / mol and (d) polyethyleneimines having an average molecular weight Mw of 500 to 10,000 g / mol.

The copolymers of vinylimidazolium methosulfate and N-vinylpyrrolidone listed under (a) contain, for example, 10 to 90% by weight of N-vinylpyrrolidone polymerized. Instead of N-vinylpyrrolidone can be used as comonomer at least one compound from the group of ethylenically unsaturated C3 to Cs carboxylic acids such as acrylic acid or methacrylic acid or esters of these carboxylic acids with 1 to 18 carbon atoms containing monohydric alcohols such as methyl acrylate, ethyl acrylate , Isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate or n-butyl methacrylate. Polymers of group (b) are preferably polydiallyldimethylammonium chloride. Also suitable are copolymers of diallyldimethylammonium chloride and dimethylaminoethyl acrylate, copolymers of diallyldimethylammonium chloride and dimethylaminoethyl methacrylate, copolymers of diallyldimethylammonium chloride and diethylaminoethyl acrylate, copolymers of diallyldimethylammonium chloride and dimethylaminopropyl acrylate, copolymers of diallyldimethylammonium chloride and dimethylaminoethylacrylamide and copolymers of diallyldimethylammonium chloride and dimethylaminopropylacrylamide. The Copoylmeri- sate of diallyldimethylammonium chloride contain, for example, 1 to 50, usually 2 to 30 mol% of at least one of said comonomers in copolymerized form.

Vinylamine-containing polymers (c) are obtainable by polymerizing N-vinylformamide optionally in the presence of comonomers and hydrolysis of the polyvinylformamides with elimination of formyl groups to form amino groups. The degree of hydrolysis of the polymers may be, for example, 1 to 100% and is preferably in the range of 60 to 100%. For the purposes of this application, partially hydrolyzed polyvinylformamides mean a degree of hydrolysis of> 50%, preferably of> 90%. The preparation of homopolymers and copolymers of N-vinylformamide and the hydrolysis of these polymers to form polymers containing vinylamine units are described in detail, for example, in US Pat. No. 6,132,558, column 2, line 36 to column 5, line 25. The statements made there are hereby incorporated by reference into the disclosure of the present invention. Vinylamine-containing polymers are sold, for example as Catiofast® ^® and Polymin® ^® trademarks of BASF Aktiengesellschaft.

Ethylenimine units containing polymers of group (d) such as polyethyleneimines are also commercial products. They are, for example, under the name Polymin® ^® from BASF Aktiengesellschaft sold eg Polymin® ^® SK. These cationic polymers are polymers of ethyleneimine obtained by polymerizing ethyleneimine in an aqueous medium in the presence of small amounts of acids or acid-forming compounds such as halogenated hydrocarbons, e.g. As chloroform, carbon tetrachloride, tetrachloroethane or ethyl chloride or condensation products of epichlorohydrin and amino-containing compounds such as mono- and polyamines z. As dimethylamine, diethylamine, ethylenediamine, diethylenetriamine and triethylenetetramine or ammonia. They have for example molar masses M _w of 500 to 1 million, preferably 1000 to 500 000 g / mol. To this group of cationic polymers also include graft polymers of ethyleneimine on compounds having a primary or secondary amino group, for. B. polyamidoamines from dicarboxylic acids and polyamines. If appropriate, the polyamidoamines grafted with ethyleneimine can also be reacted with bifunctional crosslinkers, for example with epichlorohydrin or bis-chlorohydrin ethers of polyalkylene glycols.

Suitable cationic polymers of group (e) are polymers containing dialkylaminoalkyl acrylate and / or dialkylaminoalkyl methacrylate units. These monomers may be used in the form of the free bases, but preferably in the form of the salts with mineral acids such as hydrochloric acid, sulfuric acid or phosphoric acid and in quaternized form in the polymerization. Suitable quaternizing agents are, for example, dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride, cetyl chloride or benzyl chloride. Both homopolymers and copolymers can be prepared from these monomers. Suitable comonomers are, for example, acrylamide, methacrylamide, N-vinylformamide, N-vinylpyrrolidone, methyl acrylate, ethyl acrylate, methyl methacrylate and mixtures of the monomers mentioned.

Cationic polymers of group (f) are polymers containing dimethylaminoethylacrylamide or dimethylaminoethylmethacrylamide units and containing the cationic monomers preferably in the form of salts with mineral acids or in quaternized form. These may be homopolymers and copolymers. Examples are homopolymers of dimethylaminoethylacrylamide which is completely quaternized with dimethyl sulfate or with benzyl chloride, homopolymers of dimethylaminoethylmethacrylamide which is completely quaternized with dimethylsulphate, methyl chloride, ethyl chloride or benzyl chloride, and copolymers of acrylamide and dimethylaminoethylacrylamide quaternized with dimethylsulphate.

Besides such polycations, which are composed solely of cationic monomers, amphoteric polymers can also be used as cationic polymers, provided that they carry a total cationic charge. The cationic excess charge in the amphoteric polymers is for example at least 5 mol%, preferably at least 10 mol%, and is usually in the range from 15 to 95 mol%. Examples of amphoteric polymers with a cationic excess charge are Copolymers of acrylamide, dimethylaminoethyl acrylate and acrylic acid containing at least 5 mol% more dimethylaminoethyl acrylate copolymerized than acrylic acid, - copolymers of vinylimidazolium methosulfate, N-vinylpyrrolidone and acrylic acid containing polymerized at least 5 mol% more Vinylimidazoliummethosulfat than acrylic acid, hydrolyzed from copolymers N-vinylformamide and an ethylenically unsaturated C3 to Cδ carboxylic acid, preferably acrylic acid or methacrylic acid, with a content of vinylamine units which is at least 5 mol% higher than

Units of ethylenically unsaturated carboxylic acids

Copolymers of vinylimidazole, acrylamide and acrylic acid, wherein the pH is selected so that at least 5 mol% more vinylimidazole is cationically charged than acrylic acid is copolymerized.

Polyelectrolytes which are suitable according to the invention can also be biopolymers, such as alginic acid, gum arabic, nucleic acids, pectins, proteins, and chemically modified biopolymers, such as ionic or ionizable polysaccharides, eg. As carboxymethyl cellulose, chitosan, chitosan sulfate, and lignin sulfonate.

The polyelectrolyte is preferably selected from the group comprising polyacrylic acids, phenolsulfonic acid precondensates, polydiallyldimethylammonium chlorides, polyvinylamines, partially hydrolyzed polyvinylformamides and polyethyleneimine.

According to one embodiment, anionic polyelectrolytes are preferred, in particular the polyacrylic acids and phenolsulfonic acid resins.

According to one embodiment, cationic polyelectrolytes are preferred, in particular groups (b), (c) and (d), ie polydiallyldimethylammonium chlorides, polyvinylamines and partially hydrolyzed polyvinylformamides and polyethyleneimines. Polydiallyldimethylammonium chlorides are particularly preferably used as cationic polyelectrolytes.

It is believed that the polyelectrolytes attach to the electrostatically charged microcapsule wall due to electrostatic interactions. However, it was observed that not only cationic polyelectrolytes were denser Microcapsule walls but also the addition of anionic polyelectrolytes increases the tightness of the capsule walls. These are believed to interact with the microcapsule wall via hydrogen bonds or via counterions.

The microcapsules according to the invention are obtained by constructing microcapsules comprising a capsule core and a capsule wall

10 to 100% by weight of one or more C 1 -C 24 -alkyl esters of acrylic and / or methacrylic acid (monomers I),

0 to 80% by weight of a bifunctional or polyfunctional monomer (monomer II) which is insoluble or sparingly soluble in water and 0 to 90% by weight of other monomers (monomer III)

each based on the total weight of the monomers, wherein the microcapsules have an average particle size of 1, 5 - 2.5 microns and 90% of the particles have a particle size <4 microns, in contact with one or more polyelectrolytes in water or an aqueous medium , Preferably, a microcapsule dispersion is contacted with one or more polyelectrolytes.

Preferably, they are obtained by a) preparing an oil-in-water emulsion containing the monomers, the lipophilic substance and polyvinyl alcohol and / or partially hydrolyzed polyvinyl acetate, the average size of the oil droplets being 1.5- 2.5 μm, b) the monomers of the oil-in-water emulsion obtained in a) are radically polymerized and the microcapsules optionally isolated c) the microcapsules or microcapsule dispersion obtained according to b) with one or more polyelectrolytes, if appropriate in water or an aqueous medium Contact brings.

If appropriate, the microcapsules according to the invention can subsequently be isolated by spray drying. The process step of radical polymerization b) produces an initial microcapsule dispersion as an intermediate, which is brought into contact with the polyelectrolyte in step c). The particle size distribution of the polyelectrolyte-modified microcapsule dispersion is unchanged from the initial microcapsule dispersion. Preference is given to the obtained from process step b) Microcapsule dispersion brought into contact with one or more polyelectrolytes, so without intermediate isolation of the microcapsules. Since in this case an aqueous dispersion is present, one already has the desired medium in which the microcapsules and the polyelectrolyte can be brought into contact. By bringing into contact is meant, for example, mixing with conventional stirrers or mixers.

The polyelectrolyte is added to the starting microcapsule dispersion in bulk or in solution, preferably as an aqueous solution. The amount of polyelectrolyte is 0.1 to 5 wt .-%, preferably 0.25 to 1, 5 wt .-% based on the Ausgangsmik- rokapselmenge.

The capsule wall of the microcapsules is composed of 10 to 100 wt .-%, preferably 30 to 99 wt .-% of one or more Ci-C24-alkyl esters of acrylic and / or methacrylic acid as monomers I. In addition, the polymers may contain up to 80% by weight, preferably from 1 to 70% by weight, particularly preferably from 5 to 60% by weight, in particular from 10 to 50% by weight, of a bi- or polyfunctional monomer as monomers II, which is insoluble or sparingly soluble in water, in copolymerized form. In addition, the polymers may contain up to 90% by weight, preferably 0.5 to 50% by weight, in particular 1 to 30% by weight, of other monomers III in copolymerized form.

Suitable monomers I are C 1 -C 24 -alkyl esters of acrylic and / or methacrylic acid. Particularly preferred monomers I are methyl, ethyl, n-propyl and n-butyl acrylate and / or the corresponding methacrylates. Iso-propyl, isobutyl, sec-butyl and tert-butyl acrylate and the corresponding methacrylates are preferred. Further, methacrylonitrile is mentioned. Generally, the methacrylates are preferred.

Suitable monomers II are bi- or polyfunctional monomers which are insoluble or sparingly soluble in water but have good to limited solubility in the lipophilic substance. Low solubility is to be understood as meaning a solubility of less than 60 g / l at 20 ^° C. By bi- or polyfunctional monomers is meant compounds having at least 2 non-conjugated ethylenic double bonds. In particular, divinyl and polyvinyl monomers come into consideration, which cause cross-linking of the capsule wall during the polymerization.

Preferred bifunctional monomers are the diesters of diols with acrylic acid or methacrylic acid, furthermore the diallyl and divinyl ethers of these diols. Exemplary Ethanediol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, methallyl methacrylamide and allyl methacrylate. Particular preference is given to propanediol, butanediol, pentanediol and hexanediol diacrylate or the corresponding methacrylates.

Preferred polyvinyl monomers are trimethylolpropane triacrylate and methacrylate, pentaerythritol triallyl ether and pentaerythritol tetraacrylate.

Suitable monomers III are other monomers III which are different from the monomers I and II, such as vinyl acetate, vinyl propionate, vinylpyridine and styrene. Particular preference is given to charge-bearing or ionizable group-carrying monomers IIIa which are different from the monomers I and II, such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, 2-hydroxyethyl acrylate and methacrylate, acrylamido-2-methylpropanesulfonic acid, acrylonitrile, Methacrylamide, N-vinylpyrrolidone, N-methylolacrylamide, N-methylolmethacrylamide, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate.

An embodiment in which the capsule wall of the microcapsules is constructed is particularly preferred

30 to 99 wt .-% of one or more Ci-C24-alkyl esters of acrylic and / or methacrylic acid as monomers I 1 to 70 wt .-%, preferably 5 to 60 wt .-%, in particular 10 to 50 wt. %, of a bi- or polyfunctional monomer as monomers II, which is insoluble or sparingly soluble in water,

0.5 to 50 wt .-%, preferably 1 to 30 wt .-% of other monomers purple

in each case based on the total weight of the monomers.

According to a further preferred embodiment, the wall-forming polymers of 30 to 90 wt .-% methacrylic acid, 10 to 70 wt .-% of an alkyl ester of (meth) acrylic acid, preferably methyl methacrylate, tert-butyl methacrylate, Phenylmethacrylat and cyclohexyl methacrylate, and 0 to 40 wt .-% further ethylenically unsaturated monomers formed. These further ethylenically unsaturated monomers may be the monomers I, II and / or III not previously mentioned for this embodiment. As they usually have no significant effect on the microcapsules formed this Embodiment, their proportion is preferably <20 wt .-%, in particular <10% by weight. Such monomer compositions and the preparation of microcapsule dispersions EP-A 1 251 954 described, to which reference is expressly made.

The microcapsules according to the invention can be prepared by a so-called in situ polymerization. The principle of microcapsule formation is based on preparing a stable oil-in-water emulsion from the monomers, a radical initiator, a protective colloid and the lipophilic substance to be encapsulated. Subsequently, the polymerization of the monomers is initiated by heating and optionally controlled by further increase in temperature, the resulting polymers forming the capsule wall which encloses the lipophilic substance. This general principle is described, for example, in DE-A-10 139 171, the content of which is expressly incorporated by reference.

According to the invention, an oil-in-water emulsion is prepared containing the monomers, the lipophilic substance and polyvinyl alcohol and / or partially hydrolyzed polyvinyl acetate, the average size of the oil droplets being 1.5- 2.5 μm (step a). The size of the oil droplets corresponds almost to the size of the microcapsules present after the polymerization.

It has been found that polyvinyl alcohol and / or partially hydrolyzed polyvinyl acetate as protective colloids leads to the microcapsule distributions according to the invention. In general, polyvinyl alcohol or partially hydrolyzed polyvinyl acetate are used in a total amount of at least 3% by weight, preferably from 6 to 8% by weight, based on the microcapsules (without protective colloid). It is possible to add conventional protective colloids as mentioned in WO 2005/1 16559 in addition to the amounts of polyvinyl alcohol or partially hydrolyzed polyvinyl acetate which are preferred according to the invention.

The microcapsules according to the invention are preferably prepared only with polyvinyl alcohol and / or partially hydrolyzed polyvinyl acetate and without the addition of further protective colloids.

Polyvinyl alcohol is obtainable by polymerizing vinyl acetate, optionally in the presence of comonomers, and hydrolysing the polyvinyl acetate with cleavage the acetyl groups to form hydroxyl groups. The degree of hydrolysis of the polymers may be, for example, 1 to 100%, and is preferably in the range of 50 to 100%, more preferably 65 to 95%. For the purposes of this application, partially hydrolyzed polyvinyl acetates are to be understood as meaning a degree of hydrolysis of <50% and polyvinyl alcohol of> 50 to 100%. The preparation of homo- and copolymers of vinyl acetate and the hydrolysis of these polymers to form polymers containing vinyl alcohol units are well known. Vinyl alcohol units-containing polymers are sold, for example as Mowiol ^® brands from Kuraray Specialties Europe (KSE).

Preferred are polyvinyl alcohols or partially hydrolyzed polyvinyl acetates, deren- viscosity of a 4 wt .-% aqueous solution at 20 ⁰ C in accordance with DIN 53015 has a value in the range from 3 to 56 mPa * s, preferably a value of 14 to 45 mPa * s, in particular from 22 to 41 mPa ^* s. Preference is given to polyvinyl alcohols having a degree of hydrolysis of> 65%, preferably> 70%, in particular> 75%.

The use according to the invention of polyvinyl alcohol or partially hydrolyzed polyvinyl acetate leads to a stable emulsion. This allows the polymerization, ie the wall formation to be carried out only with stirring, which only applies to better temperature compensation. The dispersing conditions for preparing the stable oil-in-water emulsion are preferably chosen as described in DE-A-10230581. In general, it is necessary to disperse until the oil droplets have the size of the desired microcapsules, since at most insignificant changes in size occur during the wall-forming process.

As free-radical initiators for the free-radical polymerization reaction, the usual peroxo and azo compounds, advantageously in amounts of 0.2 to 5 wt .-%, based on the weight of the monomers used.

Depending on the state of aggregation of the radical initiator and its solubility behavior, it can be fed as such, but preferably as a solution, emulsion or suspension, as a result of which, in particular, small amounts of radical initiator can be metered more precisely.

Preferred free-radical initiators are tert-butyl peroxoneodecanoate, tertiary

Amyl peroxypivalate, dilauroyl peroxide, tert-amyl peroxy-2-ethylhexanoate, 2,2'-azobis (2,4-dimethyl) valeronitrile, 2,2'-azobis (2-methylbutyronitrile), dibenzoyl peroxide, tert-butyl per-2-ethylhexanoate, di-tert-butyl peroxide, tert-butyl hydroperoxide, 2,5-dimethyl 2,5-di- (tert-butylperoxy) hexane and cumene hydroperoxide.

Particularly preferred radical initiators are di (3,5,5-trimethylhexanoyl) peroxide, 4,4'-azobisisobutyronitrile, tert-butyl perpivalate and dimethyl 2,2-azobisisobutyrate. These have a half-life of 10 hours in a temperature range of 30 to 100 ⁰ C.

Furthermore, it is possible to add to the polymerization known to those skilled controller in conventional amounts such as tert-dodecylmercaptan or Ethylhexylthioglycolat.

In general, the polymerization is carried out at 20 to 100 ⁰ C, preferably at 40 to 95 ° C. Depending on the desired lipophilic substance, the oil-in-water emulsion is to be formed at a temperature at which the core material is liquid / oily. Accordingly, a radical initiator must be selected whose decomposition temperature above this temperature and the polymerization are also carried out 2 to 50 ⁰ C above this temperature, so that optionally selects radical initiator whose decomposition temperature is above the melting point of the lipophilic substance.

A common process variant for lipophilic substances with a melting point up to about 60 ° C is a reaction temperature starting at 60 ° C, which is increased in the course of the reaction to 85 ° C. Advantageous free radical initiators have a 10-hour half life in the range of 45 to 65 ° C, such as t-butyl perpivalate.

After a further process variant for lipophilic substances having a melting point above 60 ⁰ C, one chooses to choose a temperature program which starts at correspondingly higher reaction temperatures. Radical initiators are preferred with a 10-hour half-life in the range of 70 to 90 ⁰ C, such as t-butyl per-2-ethylhexanoate for initial temperatures of around 85 ° C.

Conveniently, the polymerization is carried out at atmospheric pressure, but it is also possible at reduced or slightly elevated pressure z. B. at a polymerization temperature above 100 ° C, work, that is about in the range of 0.5 to 5 bar. The reaction times of the polymerization are normally 1 to 10 hours, usually 2 to 5 hours.

The inventive method using polyvinyl alcohol and / or partially hydrolyzed polyvinyl acetate allows a simplified procedure. So it is not necessary - but possible - to disperse at room temperature, but it can be dispersed and polymerized directly at elevated temperature, so that can be dispensed with the otherwise usual controlled first heating phase after the dispersion.

Following the actual polymerization reaction at a conversion of 90 to 99% by weight, it is generally advantageous to make the aqueous microcapsule dispersions substantially free of odor carriers, such as residual monomers and other volatile organic constituents. This can be achieved physically in a manner known per se by distillative removal (in particular via steam distillation) or by stripping with an inert gas. Furthermore, it can be done chemically, as described in WO 99/24525, advantageously by redox-initiated polymerization, as described in DE-A 44 35 423, DE-A 44 19 518 and DE-A 44 35 422.

Depending on the lipophilic substance, the microcapsules according to the invention are suitable for copying paper, in cosmetics, for the encapsulation of fragrances, flavorings or adhesives, or in crop protection. The microcapsules according to the invention are particularly suitable for latent heat storage materials.

By definition, latent heat storage materials are substances which have a phase transition in the temperature range in which heat transfer is to be carried out. The lipophilic substance preferably has a solid / liquid phase transition in the temperature range from -20 to 120 ^° C.

Suitable substances may be mentioned by way of example:

aliphatic hydrocarbon compounds, such as saturated or unsaturated C 10 -C 40 -hydrocarbons, which are branched or preferably linear, such as n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n- Heneicosane, n-docosane, n-tricosane, n-tetracosane, n-pentacosane, n-hexacosane, n-heptacosane, n-octacosane and cyclic hydrocarbons, eg cyclohexane, cyclooctane, cyclodecane; aromatic hydrocarbon compounds such as benzene, naphthalene, biphenyl, o- or n-terphenyl, Ci-C4o-alkyl-substituted aromatic hydrocarbons such as dodecylbenzene, tetradecylbenzene, hexadecylbenzene, hexylnaphthalene or

decylnaphthalene; saturated or unsaturated Cβ-Cso fatty acids such as lauric, stearic, oleic or behenic acid, preferably eutectic mixtures of decanoic acid with e.g. Myristic, palmitic or lauric acid; Fatty alcohols such as lauryl, stearyl, oleyl, myristyl, cetyl alcohol, mixtures such as coconut fatty alcohol and the so-called oxo alcohols, which are obtained by hydroformylation of α-olefins and further reactions; C 6 -C 30 fatty amines, such as decylamine, dodecylamine, tetradecylamine or hexadecylamine; Esters, such as C 1 -C 10 -alkyl esters of fatty acids, such as propyl palmitate, methyl stearate or ethylphenyl, and preferably their eutectic mixtures or methyl cinnamate; natural and synthetic waxes such as montan acid waxes, montan ester waxes, carnauba wax, polyethylene wax, oxidized waxes, polyvinyl ether wax, ethylene vinyl acetate wax or Fischer-Tropsch wax waxes.

Method; halogenated hydrocarbons such as chlorinated paraffin, bromoctadecane, bromopentadecane, bromononadecane, bromeicosane, bromodocosan.

Furthermore, mixtures of these substances are suitable, as long as it does not come to a melting point lowering outside the desired range, or the heat of fusion of the mixture is too low for a meaningful application.

For example, it is advantageous to use pure n-alkanes, n-alkanes having a purity of greater than 80%, or alkane mixtures, such as are obtained as a technical distillate and are commercially available as such.

Furthermore, it may be advantageous to add soluble compounds to the lipophilic substances so as to prevent the freezing point depression which sometimes occurs with the nonpolar substances. It is advantageous to use, as described in US Pat. No. 5,456,852, compounds having a melting point 20 to 120 K higher. point as the actual core substance. Suitable compounds are the fatty acids mentioned above as lipophilic substances, fatty alcohols, fatty amides and aliphatic hydrocarbon compounds. They are added in amounts of from 0.1 to 10% by weight, based on the capsule core.

Depending on the temperature range in which the heat storage are desired, the latent heat storage materials are selected. For example, it is preferred for heat storage in building materials in a moderate climate latent heat storage materials whose solid / liquid phase transition in the temperature range of 0 to 60 ⁰ C. Thus, one usually chooses for indoor applications, or mixtures with conversion temperatures of 15 to 30 ⁰ C. In solar applications as a storage medium or to avoid overheating of transparent thermal insulation, as described in EP-A-333 145, are mainly conversion temperatures of 30-60 ° C suitable. For applications in the textile sector, especially transition temperatures of 0 to 40 ⁰ C advantageous for heat transfer fluids from -10 to 120 ⁰ C.

Preferred latent heat storage materials are aliphatic hydrocarbons, particularly preferably those listed above by way of example. In particular, aliphatic hydrocarbons having 14 to 20 carbon atoms and mixtures thereof are preferred.

The present invention further relates to microcapsules comprising a capsule core and a capsule wall constructed from

10 to 100 wt .-% of one or more Ci-C24-alkyl esters of acrylic and / or methacrylic acid (monomers I), 5 to 60 wt .-% of a bi- or polyfunctional monomer (monomers II), which in water is insoluble or sparingly soluble and 0 to 85% by weight of other monomers (monomer III)

wherein the microcapsules have an average particle size of 1, 5 - 2.5 microns and 90% of the particles have a particle size <4 microns, preferably <3.5 microns, in particular <3 microns have as an intermediate. The half-width of the microcapsule distribution is 0.2 to 1.5 μm, preferably 0.4 to 1 μm. The intermediate is obtained according to the method described above. The aqueous dispersions of the microcapsules obtained according to the invention allow a reaction without further intermediate isolation. tion of the microcapsules to the electrolyte-carrying microcapsules according to the invention. In addition, it also has advantageous properties even in some applications of microencapsulated latent heat storage materials.

The application of the microcapsule powder according to the invention is diverse. Thus, it is advantageous to use for modifying fibers and fabrics, for example, textile fabrics and nonwovens (e.g., nonwovens), etc. In particular, microcapsule coatings, foams with microcapsules and microcapsule-modified textile fibers may be mentioned as application forms. For coatings, the microcapsules are applied to a fabric together with a polymeric binder and optionally other excipients, usually as a dispersion. Typical textile binders are film-forming polymers having a glass transition temperature in the range from -45 to 45 ° C, preferably -30 to 12 ° C. The preparation of such microcapsule coatings is described, for example, in WO 95/34609, to which reference is expressly made. The modification of foams with microcapsules is carried out in a similar manner as described in DE 981576T and US 5,955,188. The prefoamed substrate, preferably a polyurethane or polyether, is surface-treated with a binder-containing microcapsule dispersion. Subsequently, the binder-microcapsule mixture passes by applying a vacuum in the open-pore foam structure in which the binder hardens and binds the microcapsules to the substrate. Another processing option is the modification of the textile fibers themselves, e.g. by spinning from a melt or an aqueous dispersion as described in US 2002/0054964. Melt spinning processes are used for nylon, polyester, polypropylene fibers and similar fibers, while the wet spinning process is mainly used for the production of acrylic fibers.

The microcapsule powder according to the invention has a good chemical cleaning resistance.

Another broad field of application are binders with mineral, silicate or polymeric binders. A distinction is made between moldings and coating compositions. They are characterized by their resistance to hydrolysis against the aqueous and often alkaline aqueous materials. A mineral shaped body is understood to be a shaped body which is formed from a mixture of a mineral binder, water, additives and, if appropriate, auxiliaries after shaping by hardening the mineral binder / water mixture as a function of time, optionally under the effect of elevated temperature. Mineral binders are well known. It is finely divided inorganic substances such as lime, gypsum, clay, loam and / or cement, which are transferred by mixing with water in their ready-to-use form, the latter being left to itself, in the air or under water, optionally under the action elevated temperature, as a function of time stone-like solidify.

The aggregates are usually made of granular or fibrous natural or artificial rock (gravel, sand, glass or mineral fibers), in special cases also of metals or organic aggregates or mixtures of said aggregates, with grain sizes or fiber lengths, the respective purpose in are adapted in a known manner. Frequently, for the purpose of coloring and colored pigments are also used as surcharges.

Suitable auxiliaries are, in particular, those substances which accelerate or retard the hardening or which influence the elasticity or porosity of the solidified mineral shaped body. These are in particular polymers, as z. For example, from US-A 4,340,510, GB-PS 1 505 558, US-A 3,196,122, US-A 3,043,790, US-A 3,239,479, DE-A 43 17 035, DE-A 43 17 036 , JP-A 91/131 533 and other writings are known.

The polyelectrolyte-modified microcapsules according to the invention and their unmodified intermediate are suitable for modifying mineral binders (mortar-like preparations) containing a mineral binder consisting of 70 to 100% by weight of cement and 0 to 30% by weight of gypsum. This is especially true when cement is the sole mineral binder. The effect according to the invention is essentially independent of the type of cement. Depending on the project so blast furnace cement, oil shale cement, Portland cement, hydrophobic Portland cement, quick-setting cement, swelling cement or alumina cement can be used, with the use of Portland cement proves to be particularly favorable. For further details, reference is made to DE-A 196 23 413. Typically, the dry compositions of mineral binders, based on the amount of mineral binder, contain 0.1 to 20 wt .-% microcapsules. The polyelectrolyte-modified microcapsules according to the invention and their unmodified intermediate are preferably used as additives in mineral coating compositions such as plaster. Such a plaster for the interior is usually composed of gypsum as a binder. As a rule, the weight ratio of gypsum / microcapsule is from 95: 5 to 70: 30. Higher microcapsule proportions are, of course, possible.

Exterior coatings such as exterior facades or damp rooms may contain cement (cementitious plasters), lime or waterglass (mineral or silicate plasters) or plastic dispersions (synthetic resin plasters) as binders together with fillers and optionally coloring pigments. The proportion of microcapsules in the total solids corresponds to the weight ratios for gypsum plasters.

Furthermore, the polyelectrolyte-modified microcapsules according to the invention and their unmodified intermediate are suitable as additives in polymeric moldings or polymeric coating compositions. These are thermoplastic and thermosetting plastics to understand in their processing, the microcapsules are not destroyed. Examples are epoxy, urea, melamine, polyurethane and silicone resins and also paints both solvent-based, high-solids-based, powder coating or water-based paint and dispersion films. The microcapsule powder is also suitable for incorporation in plastic foams and fibers. Examples of foams are polyurethane foam, polystyrene foam, latex foam and melamine resin foam.

Furthermore, the polyelectrolyte-modified microcapsules according to the invention and their unmodified intermediate are suitable as additives in lignocellulose-containing moldings, such as chipboard.

Advantageous effects can also be achieved if the polyelectrolyte-modified microcapsules according to the invention and their unmodified intermediate are processed in mineral moldings which are foamed.

Furthermore, the polyelectrolyte-modified microcapsules according to the invention and their unmodified intermediate are suitable for modifying plasterboard. In this case, preferably 5 to 40 wt .-%, in particular 20 to 35 wt .-%, microcapsule powder based on the total weight of the gypsum plasterboard (dry matter) incorporated. The production of plasterboard with microencapsulated latent heat storage is well known and described in EP-A 1 421 243 which is incorporated herein by reference. Alternative fibrous structures may also be used as double-sided covers for the "gypsum board" instead of cellulose-based board Alternative materials include polymer fibers made from, for example, polypropylene, polyester, polyamide, polyacrylates, polyacrylonitrile and the like The alternative materials can be used as fabric and as so-called "nonwovens", ie as fleece-like structures. Such structural panels are known for example from US 4,810,569, US 4,195,110 and US 4,394,411.

Furthermore, the polyelectrolyte-modified microcapsules according to the invention and their unmodified intermediate are suitable for the production of heat transfer fluid. The term heat transfer fluid in the context of this application, both liquids for the transport of heat as well as liquids for the transport of cold, ie cooling liquids meant. The principle of heat energy transfer is the same in both cases and differs only in the direction of transfer.

The following examples are intended to explain the invention in more detail. The percentages in the examples are by weight unless otherwise specified.

The particle size of the microcapsule powder was determined with a Malvern Particle Sizer Type 3600E according to a standard measuring method documented in the literature. The half-width is the width of the distribution halfway up the maximum. The D (0, 9) value indicates that 90% of the particles have a particle size (by volume) less than or equal to this value. The D (0, 1) value indicates that 10% of the particles have a particle size (by volume average) up to this value. Correspondingly, D (0, 5) means that 50% of the particles have a particle size (by volume) less than or equal to this value. The span value results from the quotient of the difference (D (0, 9) - D (0, 1)) and D (0, 5).

Determination of the exhaust steam rate

For pretreatment, 2 g of the microcapsule dispersion were dried in a metal dish at 105 ^° C. for two hours in order to remove any residual water. Then the weight (m ₀ ) was determined. After heating for one hour at 180 ^° C., the weight (mi) is again determined after cooling. The weight difference (mo - mi) with respect to mθ indicates the evaporation rate.

Preparation of the microcapsule dispersion

Example 1 (without polyelectrolyte)

Water phase 330 g of water

220 g of a 10 wt .-% aqueous solution of polyvinyl alcohol (with a viscosity of a 4 wt .-% solution at 20 ⁰ C of 40 mPa * s according to DIN 53015 and a degree of saponification of 88%; Mowiol 40-88 the company Kuraray Specialties Europe (KSE)), 4.4 g of decanoic acid

oil phase

440 g paraffin with melting point 62 to 64 ° C

58.2 g of methyl methacrylate 19.4 g of butanediol diacrylate

0.8 g of ethylhexyl thioglycolate

Addition 1

0.92 g of a 75% strength by weight solution of tert-butyl perpivalate in aliphatic hydrocarbons,

Addition 2

7.63 g of a 10 wt .-% aqueous solution of tert-butyl hydroperoxide

Inlet 1

28.34 g of a 1, 1 wt .-% aqueous solution of ascorbic acid

a) At 70 ⁰ C, the above water phase was presented and after addition of the oil phase was dispersed with a high-speed Dissolverrührer at 6000 rpm. After 40 minutes of dispersion, a stable emulsion of mean particle size D [4.3] = 1.9 μm was obtained. b) Addition 1 was added and the emulsion was kept under stirring at 2500 rpm for 60 minutes at a temperature of 70 ⁰ C. The mixture was then heated to a temperature of 85 ⁰ C over a period of 60 minutes and held the emulsion for another hour at this temperature. Addition 2 was added and the resulting microcapsule dispersion was cooled to 20 ^° C. with stirring over 30 minutes while feed 1 was added.

The resulting microcapsule dispersion had a solids content of 49% and an average particle size D [4.3] = 1.94 μm (measured by Fraunhoferbeugung). The half-width of the distribution was 0.65 μm, the D (0, 9) = 2.26 and the evaporation rate 4.2%.

Example 2 (without polyelectrolyte)

a) A mixture of 309 g of a 10% strength by weight aqueous polyvinyl alcohol solution (Mowiol 40-88), 2.1 g of a 2.5% strength by weight aqueous solution of sodium nitrite and 250 g of water was initially charged. To this water phase, a mixture of 431 g techn. Octadecane, (91% purity), 9 g Sasolwax 6805

(higher melting paraffin from Sasol Wax), 50.4 g of methyl methacrylate, 19.4 g of butanediol diacrylate, 7.8 g of methacrylic acid, 0.76 g of ethylhexyl thioglycolate and 0.7 g of a 75 wt .-% solution of tert-butyl perpivalate in metered aliphatic hydrocarbons and the mixture with a high-speed Dissolverrührer dispersed at 4000 rpm. After 40 minutes of dispersion, a stable emulsion of average particle size D [4.3] = 2.36 μm (diameter) was obtained.

b) Subsequently, 250 g of water were added and the emulsion was heated with stirring with an anchor ram over a period of 60 minutes at 70 ⁰ C and over a period of 60 minutes at 85 ⁰ C and held at this temperature for one hour. 5.38 g of a 10% strength by weight aqueous tert-butyl hydroperoxide solution were added and the resulting microcapsule dispersion was cooled to 20.degree. C. with stirring within 30 minutes, while 28.3 g of a 1.1% by weight aqueous ascorbic acid solution were added. In addition, 2.00 g of 25% sodium hydroxide solution, 1.43 g of water and 5.03 g of a 30 % strength by weight aqueous thickener solution (Viscalex HV 30) added in order to prevent creaming of the dispersion.

The resulting microcapsule dispersion had a solids content of 40% and an average particle size D [4.3] = 2.36 μm (measured by Fraunhoferbeugung), D (0, 9) = 2.88 microns, the half-width of the distribution was 0.68 microns , the chip 0.39, the evaporation rate was 7.0%.

Example 3 (without polyelectrolyte)

a) A mixture of 206 g of a 10 wt .-% aqueous solution of polyvinyl alcohol (Mowiol 15-79), 2.1 g of a 2.5 wt .-% aqueous solution of sodium nitrite and 350 g of water submitted. To this water phase, a mixture of 431 g techn. Octadecane (91% pure), 9 g Sasolwax 6805 (higher melting paraffin, 31, 9 g) methyl methacrylate, 12.3 g butanediol diacrylate, 4.9 g methacrylic acid, 0.76 g ethylhexyl thioglycolate, 0.7 g of a 75 wt .-% solution of tert-butyl perpivalate added in aliphatic hydrocarbons and the mixture with a high-speed Dissolverrührer dispersed at 6000 rpm. After dispersing for 60 minutes, a stable emulsion of the mean particle size D [4.3] = 2.57 μm was obtained.

b) Subsequently, 150 g of water and 103 g of a 10% strength by weight aqueous polyvinyl alcohol solution (Mowiol 15-79) were added. The emulsion ^'is now heated with stirring with an anchor stirrer over a period of 60 minutes at 70 ⁰ C and over a period of 60 minutes at 85 ⁰ C and held for one hour at this temperature. There were added 5.38 g of a 10 wt .-% aqueous tert-butyl hydroperoxide solution and the resulting microcapsule dispersion was cooled within 30 minutes with stirring to 20 ⁰ C, while 28.3 g of a 1, 1 wt .-% aqueous ascorbic acid were added to adjust the pH to 7.

The resulting microcapsule dispersion had a solids content of 39% and an average particle size D [4.3] = 1.98 μm (measured by Fraunhoferbeugung), D (0, 9) = 2.34 .mu.m, the half-width of the distribution was 0.55 μm, the chip 0.35, the evaporation rate was 35.7%. Example 4 (without polyelectrolyte)

water phase

425 g of water 412 g of a 10% strength by weight aqueous polyvinyl alcohol solution (Mowiol 40-88)

2.1 g of a 2.5% strength by weight aqueous sodium nitrite solution

oil phase

431 g techn. Octadecane, (purity 91%) 9 g Sasolwax 6805 (higher melting paraffin

50.4 g of methyl methacrylate

19.4 g of butanediol diacrylate

7.8 g of methacrylic acid

0.76 g Ethylhexylthioglycolat 0.7 g of a 75 wt .-% solution of tert-butyl perpivalate in aliphatic hydrocarbons

Addition 1

5.38 g of a 10% by weight aqueous tert-butyl hydroperoxide solution

Inlet 1

28.3 g of a 1, 1 wt .-% aqueous ascorbic acid

Addition 2 1, 00 g of a 25% sodium hydroxide solution

1, 43 g of water

a) At 40 ⁰ C, the above water phase was presented and after addition of the oil phase was dispersed with a high-speed Dissolverrührer at 6000 rpm. After 40 minutes of dispersion, a stable emulsion of average particle size D [4,3] = 1, 96 microns in diameter was obtained.

b) The emulsion was heated with stirring with an anchor crater over a period of 60 minutes to a temperature of 70 ⁰ C and heated to a temperature of 85 ⁰ C for a further 60 minutes. Subsequently, the mixture was kept at this temperature for one hour. Addition 1 was added. and the resulting microcapsule dispersion was cooled to 20 ^° C. with stirring within 30 minutes while feed 1 was added thereto. Addition 2 was added to adjust the pH to pH = 7.

The resulting microcapsule dispersion had a solids content of 40% and an average particle size D [4.3] = 2.17 μm (measured by Fraunhoferbeugung), D (0, 9) = 2.64 microns, the half-width of the distribution was 0.58 μm, the chip 0.42, the evaporation rate was 21, 4%.

Example 5 (with polyelectrolyte)

100 g of the obtained according to Example 4 microcapsule dispersion (solids content 40% by weight) was then added with stirring with 2 g of a 20 wt .-% aqueous solution of a phenol sulfonic acid polycondensate (Tamol ^® DN, BASF Aktiengesellschaft). The evaporation rate was only 3.6%, with unchanged particle size distribution in comparison to Example 4.

Example 6 (with polyelectrolyte)

100 g of the obtained according to Example 4 microcapsule dispersion (solids content 40% by weight) was then with stirring with 1, 33 g of a 30% aqueous solution of a poly (N, N-diallyl-N, N-dimethylammonium chloride) based cationic polymer with a viscosity of 500 mPa ^* s according to ISO 2555 (Catiofast ^® CS, BASF Aktiengesellschaft). The evaporation rate was only 5.8%, with unchanged in comparison to Example 4 particle size distribution.

Example 7 (without polyelectrolyte)

Water phase 425 g of water

412 g of a 10% strength by weight aqueous polyvinyl alcohol solution (Mowiol 40-88) 2.1 g of a 2.5% strength by weight aqueous sodium nitrite solution

oil phase

431 g techn. Octadecane, (purity 91%)

9 g Sasolwax 6805 (higher melting paraffin 50.4 g methyl methacrylate

19.4 g of butanediol diacrylate 7.8 g of methacrylic acid

0.76 g of ethyl hexyl thioglycolate

0.7 g of a 75 wt .-% solution of tert-butyl perpivalate in aliphatic hydrocarbons

Addition 1

5.38 g of a 10% strength by weight aqueous tert-butyl hydroperoxide solution,

Feed 1 28.3 g of a 1, 1 wt .-% aqueous ascorbic acid

Addition 2

1, 00 g of 25% sodium hydroxide solution 1, 43 g of water

a) At 70 ⁰ C, the above water phase was presented and after addition of the oil phase was dispersed with a high-speed Dissolverrührer at 6000 rpm. After 40 minutes of dispersion, a stable emulsion of mean particle size D [4.3] = 2.3 μm diameter was obtained.

b) The emulsion was kept under stirring with an anchor butt for 60 minutes at 70 ⁰ C, heated to 85 ⁰ C within another 60 minutes and held at this temperature for one hour. Addition 1 was added and the resulting microcapsule dispersion was cooled to 20 ^° C. with stirring within 30 minutes while feed 1 was added. Addition 2 was added to adjust the pH to 7.

The resulting microcapsule dispersion had a solids content of 40% and an average particle size D [4.3] = 2.25 μm (measured by Fraunhoferbeugung), D (0, 9) = 2.55 microns, the half-width of the distribution was 0.68 μm, the chip 0.26, the evaporation rate was 9.6%. Example 8 (without polyelectrolyte) water phase 437 g of water

12 g of a 32% strength by weight ionic emulsifier (Disponil® FES77, Cognis)

412 g of a 10% strength by weight aqueous polyvinyl alcohol solution (Mowiol 40-88), 10% in water

2.1 g of a 2.5% strength by weight aqueous sodium nitrite solution

oil phase

431 g techn. Octadecane, (purity 91%)

9 g Sasolwax 6805 (higher melting paraffin

50.4 g of methyl methacrylate 19.4 g of butanediol diacrylate

7.8 g of methacrylic acid

0.76 g of ethyl hexyl thioglycolate

Addition 1

5.38 g of a 10% by weight aqueous tert-butyl hydroperoxide solution

Feed 1 28.3 g of a 1, 1 wt .-% aqueous ascorbic acid

Addition 2

1.50 g of 25% strength by weight sodium hydroxide solution 1.43 g of water

a) At 40 ⁰ C, the above water phase was presented and after addition of the oil phase was dispersed with a high-speed Dissolverrührer at 6000 rpm. After 40 minutes of dispersion, a stable emulsion of mean particle size D [4,3] = 1.81 μm diameter was obtained. b) The emulsion was brought with stirring with an anchor crusher within 60 minutes at 70 ⁰ C, heated within another 60 minutes at 85 ⁰ C and held at this temperature for one hour. Addition 1 was added and the resulting microcapsule dispersion was cooled to 20 ^° C. with stirring within 30 minutes while feed 1 was added. Addition 2 was added to adjust the pH to pH = 7.

The resulting microcapsule dispersion had a solids content of 40% and an average particle size D [4.3] = 1.88 μm (measured by Fraunhoferbeugung), D (0, 9) = 2.15 microns, the half-width of the distribution was 0.65 μm, the chip 0.28, the evaporation rate was 15.3%.

Example 9 (without polyelectrolyte)

water phase

437 g of water

1 g of an ionic emulsifier (Tween 20)

412 g of a 10% strength by weight aqueous polyvinyl alcohol solution (Mowiol 40-88),

2.1 g of a 2.5% strength by weight aqueous sodium nitrite solution

oil phase

431 g techn. Octadecane, (91% purity)

9 g Sasolwax 6805 (higher melting paraffin

50.4 g of methyl methacrylate 19.4 g of butanediol diacrylate

7.8 g of methacrylic acid

0.76 g of ethyl hexyl thioglycolate

Addition 1

5.38 g of a 10% strength by weight aqueous tert-butyl hydroperoxide solution,

Feed 1 28.3 g of a 1, 1 wt .-% aqueous ascorbic acid Addition 2

, , 00 g of 25% sodium hydroxide solution 1, 43 g of water

a) At 40 ⁰ C, the above water phase was presented and after addition of the oil phase was dispersed with a high-speed Dissolverrührer at 6000 rpm. After 40 minutes of dispersion, a stable emulsion of mean particle size D [4.3] = 2.09 μm in diameter was obtained.

b) The emulsion was brought with stirring with an anchor crusher within 60 minutes at 70 ⁰ C, heated within another 60 minutes at 85 ⁰ C and held at this temperature for one hour. Addition 1 was added and the resulting microcapsule dispersion was cooled to 20 ^° C. with stirring within 30 minutes while feed 1 was added. Addition 2 was added to adjust the pH to pH = 7.

The resulting microcapsule dispersion had a solids content of 40% and an average particle size D [4.3] = 2.08 μm (measured by Fraunhoferbeugung), D (0, 9) = 2.45 .mu.m, the half-width of the distribution was 0.71 μm, the chip 0.36, the evaporation rate was 12.2%.

Example 10 (without polyelectrolyte, not according to the invention)

Water phase 380 g of water

190 g of a 5 wt .-% aqueous dispersion of methyl hydroxypropyl cellulose

(Culminal MHPC ^® 100) 47.5 g of a 10 wt .-% aqueous polyvinyl alcohol (Mowiol 15-79)

2.1 g of a 2.5% strength by weight aqueous Na nitrite solution

oil phase

431 g techn. Octadecane, (91% purity)

9 g Sasolwax 6805 (higher melting paraffin)

19.6 g of methyl methacrylate 19.6 g of butanediol diacrylate

9.8 g of methacrylic acid 0.7 g of a 75 wt .-% solution of tert-butyl perpivalate in aliphatic hydrocarbons

Addition 1 5.38 g of a 10% strength by weight aqueous solution of tert-butyl hydroperoxide

Inlet 1

28.3 g of a 1, 1 wt .-% aqueous solution of ascorbic acid

a) At 40 ⁰ C, the above water phase was presented and after addition of the oil phase was dispersed with a high-speed Dissolverrührer at 6000 rpm. After 40 minutes of dispersion, a stable emulsion of mean particle size D [4.3] = 3.6 μm diameter was obtained.

b) The emulsion was heated with stirring with an anchor crusher over a period of 60 minutes at 70 ⁰ C, heated to a temperature of 85 ⁰ C within another 60 minutes and held at this temperature for one hour. It Addition 1 was added and the resulting microcapsule dispersion is cooled within 30 minutes with stirring to 20 ⁰ C, while feed 1 was added dazu-.

The resulting microcapsule dispersion had a solids content of 44% and an average particle size D [4.3] = 3.5 μm (measured by Fraunhoferbeugung), D (0, 9) = 5.67 microns, the half-width of the distribution was 2.8 μm, the chip 1, 33, the evaporation rate was 3.8%.

Claims

claims

1. microcapsules comprising a capsule core, a capsule wall and arranged on the outer surface of the capsule wall polyelectrolytes having a median molecular weight of 500 g / mol to 10 million g / mol, the capsule wall is constructed from

10 to 100 wt .-% of one or more Ci-C24-alkyl esters of acrylic and / or

Methacrylic acid (monomers I), 0 to 80 wt .-% of a bifunctional or polyfunctional monomer (monomers II), which is insoluble or sparingly soluble in water and 0 to 90 wt .-% of other monomers (monomer III)

in each case based on the total weight of the monomers, characterized in that the microcapsules have an average particle size of 1, 5-2.5 μm and 90% of the particles have a particle size <4 μm.

2. microcapsules according to claim 1, wherein the Polyelektrolytmenge 0.1 to 10% by weight based on the total weight of the microcapsules.

3. Microcapsules according to one of claims 1 or 2, wherein it is one or more cationic polyelectrolytes.

4. microcapsules according to one of claims 1 to 3, wherein the capsule wall is built up from

10 to 100 wt .-% of one or more Ci-C24-alkyl esters of acrylic and / or

Methacrylic acid (monomers I),

5 to 60 wt .-% of a bifunctional or polyfunctional monomer (monomers II), which is insoluble or sparingly soluble in water, and

0 to 85% by weight of other monomers (monomer III)

in each case based on the total weight of the monomers.

5. Microcapsules according to one of claims 1 to 4, wherein the capsule core is a populist material with a solid / liquid phase transition in the temperature range from -20 to 120 ⁰ C.

6. A process for the preparation of microcapsules according to claims 1-5, comprising microcapsules comprising a capsule core and a capsule wall constructed from

10 to 100 wt .-% of one or more Ci-C24-alkyl esters of acrylic and / or

Methacrylic acid (monomers I),

each based on the total weight of the monomers, wherein the microcapsules have an average particle size of 1, 5 - 2.5 microns and 90% of the particles have a particle size <4 microns, in contact with one or more polyelectrolytes in water or an aqueous medium ,

A process for the preparation of microcapsules according to claim 6, by bringing a microcapsule dispersion in contact with one or more polyelectrolytes.

8. A process for the preparation of microcapsules according to claim 6, by

a) an oil-in-water emulsion containing the monomers, the lipophilic substance and polyvinyl alcohol or partially hydrolyzed polyvinyl acetate produces, wherein the average size of the oil droplets is 1, 5 - 2.5 microns, b) the monomers of the obtained according to a) Free-radically polymerizing oil-in-water emulsion and c) bringing the microcapsule dispersion obtained according to b) into contact with one or more polyelectrolytes.

9. microcapsules obtainable according to the methods of claims 6 to 8.

10. microcapsules comprising a capsule core and a capsule wall constructed from

10 to 100 wt .-% of one or more Ci-C24-alkyl esters of acrylic and / or

Methacrylic acid (monomers I), 5 to 60% by weight of a bifunctional or polyfunctional monomer (monomer II) which is insoluble or sparingly soluble in water and 0 to 85% by weight of other monomers (monomer III)

each based on the total weight of the monomers, characterized in that the microcapsules have an average particle size of 1, 5 - 2.5 microns and 90% of the particles have a particle size <4 microns.

1 1. microcapsules according to claim 10 in the form of an aqueous dispersion.

12. A process for the preparation of microcapsules according to claim 10 or 1 1, by

a) an oil-in-water emulsion containing the monomers which produces lipophilic substance and polyvinyl alcohol and / or partially hydrolyzed polyvinyl acetate, wherein the average size of the oil droplets is 1, 5-2.5 μm, and b) the monomers the obtained in a) oil-in-water emulsion radically polymerized.

13. Use of the microcapsules according to claims 1 to 5 and 9 for incorporation in textiles.

14. Use of the microcapsules according to claims 1 to 5 and 9 in bindings.

15. Use of the microcapsule dispersion according to claims 1 to 5 and 9 in heat transfer fluids.

16. Use of the microcapsules according to claim 10 or 1 1 for incorporation in textiles.

17. Use of the microcapsules according to claim 10 or 11 in bindings.

18. Use of the microcapsule dispersion according to claim 10 or 11 in heat transfer fluids.