EP2838925A1

EP2838925A1 - Polymerizates that can be produced by the emulsion polymerization of functionalized polyurethane nanoparticles and radically curable monomers, a method for the production of said polymerizates, and use of said polymerizates

Info

Publication number: EP2838925A1
Application number: EP13721608.1A
Authority: EP
Inventors: Jorge Rodriguez Prieto; Klaus-Uwe Koch; Kirsten Siebertz
Original assignee: Dritte Patentportfolio Beteiligungs GmbH and Co KG
Current assignee: LEHMANN & VOSS & CO. KG
Priority date: 2012-04-16
Filing date: 2013-04-16
Publication date: 2015-02-25
Also published as: JP2015514155A; DE102012007823A1; US20150072080A1; WO2013156486A1

Abstract

The invention relates to polymerizates that can be obtained by a) reacting at least one polyisocyanate with at least one polyol and optionally at least one radically curable monomer A with groups reactive toward isocyanate in at least one radically curable monomer B to form polyurethane particles having an average diameter of less than 40 nm, preferably less than 20 nm, and especially preferably less than 10 nm and an average number of radically curable functionalities in a range of 2 to 4, preferably 2 to 3, and b) emulsion polymerizing the product obtained under a). By means of the emulsion polymerization, larger cross-linked polyurethane/polymer hybrid dispersions are produced, in which the nanoparticles act as a connecting member between the polymer areas and the polyurethane components. This structure results in improved chemical resistance and significantly improved mechanical properties in comparison with traditional polyurethane dispersions, in which polyurethane nanoparticles are subsequently dispersed in polyacrylates, for example by means of an acetone method. Furthermore, the content of polyurethane in the polymer can be better controlled by means of this production method. The invention further relates to a method for producing such polymerizates and the use of such polymerizates as adhesives or coatings, in particular for textiles, or as paints, or for films and foils.

Description

POLYMERISATE DERIVED BY EMULSION POLYMERIZATION OF

FUNCTIONALIZED POLYURETHANE NANOPARTICLES AND RADICALLY HARDENABLE MONOMERS ARE MANUFACTURABLE, A METHOD THEREFOR

PREPARATION AND THEIR USE.

description

The present invention relates to polymers which are obtainable by reacting at least one polyisocyanate with at least one polyol and at least one free-radically curable monomer A with isocyanate-reactive groups in at least one free-radically curable monomer B.

Polyurethane particles having an average diameter of less than 40 nm, preferably less than 20 nm and more preferably less than 10 nm and an average number of free-radically curable functionalities in the range of 2 to 4, preferably 2 to 3, and subsequent emulsion polymerization of the product obtained are. These polymers are suitable for

Application in adhesives, paints or as coating material, such as e.g. for application to sheet materials, e.g. Textiles. Another aspect of the present invention relates to a process for producing such

Polymers.

Polymer dispersions have gained in many applications, such as coating, adhesives and adhesives or in the paint sector, important because they can be processed in contrast to solvent-based suspensions or solutions without polluting and expensive solvents. For example, EP 1 015 507 A1 describes aqueous polyurethane dispersions which can be used as lacquer for a number of substrates, including wood or metals, glass, Cloth, leather, paper or plastic and can be applied by methods such as dipping, flow coating, spraying or similar methods. The aqueous carrier medium is removed from the coating after application by drying.

It is also known that the properties of polyurethane varnishes derived from aqueous dispersions can be modified by incorporating vinyl polymers, especially acrylic polymers, into the dispersions. For example, the use of acrylic polymers can result in improved hardness of the resulting paint coating. Such dispersions contain the polyurethane and vinyl polymer components as a physical mixture.

In addition, various patent applications, such as US 3,705,164, US 4,198,330 and 4,318,833, describe processes in which a vinyl polymer is formed in situ by polymerizing one or more vinyl polymers in the presence of a polyurethane containing pendant anionic groups in aqueous dispersion. Such in situ formation of the vinyl monomer has the advantage that in many cases its dispersion stability is higher and the properties of resulting coatings are markedly improved compared to simple mixtures of the polyurethanes and vinyl polymers.

EP 0 666 275 describes water-based polyurethane / acrylic polymer dispersions which are suitable for films and film laminations as well as flexible packaging materials. These polyurethane / acrylic polymer dispersions are based on polyisocyanates functionalized with carboxylic acid side chains to form anionic water-dispersible prepolymers. These can then be modified by chain extension and converted by polymerization of the acrylate monomers in the mixture to give polyurethane acrylate polymer dispersions.

US 5,371,133 describes a process for the preparation of

Polyurethane / acrylate or vinyl latexes for use in aqueous adhesives or paints where the urethane polymer has only urethane linkages (ie, no additional urea linkages). EP 0 309 114 A1 discloses an aqueous polymer dispersion containing a

Vinyl polymer and a nonionic water-dispersible polyurethane with polyethylene oxide side chains contains. The vinyl polymer is prepared by radical polymerization of at least one vinyl monomer in the presence of an aqueous dispersion of the polyurethane.

Finally, US Pat. No. 6,787,596 A1 discloses the stepwise preparation of a polyurethanepredispersion containing a proportion of additional acrylate polymer. For this purpose, an acid functionalities containing first

Polyurethane polymer prepared in aqueous dispersion, which is then added to an acrylate component and also polymerized in an aqueous phase.

Also known are nonaqueous polyurethane / acrylate dispersions (also referred to as 100% systems or reactive systems) in which

Polyurethane particles are dispersed in a reactive solvent which can be cured in a subsequent polymerization step. Such dispersions can be cured, for example by means of UV radiation and show advantageous in applications such as bonding of glass, wood, metal or plastic or in painting in the furniture and parquet area

Application properties. By way of example for such nonaqueous dispersions, reference is made to EP 1 910 436, which discloses polyurethane polymer particles in

Acrylate monomers disclosed as reactive diluents, wherein the small size of the polyurethane particles to transparent products with good at the same time

mechanical properties leads.

In many applications in which dispersions are applied over a large area and applied in partially inaccessible areas, subsequent curing of free-radically curable monomers is associated with difficulties, since the completeness of the polymerization can not be guaranteed in all cases. However, unpolymerized monomers present a problem because the residual monomers can be released from the material over time and are often associated with significant odor nuisance. This is problematic especially in textile applications, since the finished Textiles come in contact with skin. Likewise, complete polymerization on thick layers is problematic.

Aqueous dispersions have other important advantages over solvent-borne or 100% solids-containing dispersions (100% non-volatile content) in the application. Thus, dispersions based on high molecular weight polymers can be prepared and processed very well, since the viscosity of the dispersion is generally independent of the degree of polymerization. After removal of the water by means of physical drying very dry surfaces are obtained, which is associated with advantages for many coating processes.

Furthermore, compared to high-solids coating systems or adhesives (up to 100%), aqueous dispersions can be reproducibly applied as thin layers. Finally, aqueous dispersions are advantageous for applications in which matte surfaces are desired, since "matting" can be accomplished easily and gloss levels of less than 3E (60 ° measurement angle) can be set.

There is therefore a further need for polymers, in particular

Emulsion polymers which show advantageous properties in applications, for example in the adhesive sector, in the paint sector or for coatings.

In addition, there is a need for polymers that are available from relatively few components to make production more economical.

The objects described above are carried out with a polymer according to

Claim 1 solved. In the dependent claims 2 to 9 are advantageous

Embodiments of the polymer according to claim 1 specified. A process for the preparation of the polymer according to the invention is specified in claims 10 to 17. Claims 17 to 19 relate to uses for which the polymer according to the invention is suitable. In claim 1, only the

Monomer A, but not to consider the monomer B as an optional component.

Because of the nanostructuring of the polyurethane particles having a particle size of less than 40 nm, the polymers in the form of adhesives, lacquers or coatings have an advantageous transparency. In addition, point adhesives prepared from the polymers according to the invention have a high impact strength, are easily controllable with regard to their elasticity and have a very high adhesive strength and resistance. Accordingly, in these applications, the polyurethane particles fulfill the function of an impact modifier. In addition, paints prepared from the polymers according to the invention have a high resistance to micro-scratches. Surprisingly, it has also been found that the emulsion polymerization polymers according to the invention are distinguished, by comparison with corresponding emulsion polymers without polyurethane nanoparticles, by improved adhesive strengths on different substrates and improved wood firing.

By "Holzanfeuerung" is referred to in connection with the present invention, the color depression, which occurs during the wetting of a wood surface through the coating material and permanently emphasizing the wood grain (see.

Prieto / None, "Holzbeschichtung, Coatings Compendien, Curt Vincentz-Verlag, Hannover, 2007).

Compared with the previously widely used solutions of polyurethane impact modifiers, the polymer according to the invention is characterized in that in him, based on the total weight of

Composition, a higher proportion of polyurethane particles may be contained, as in solutions of polyurethanes in a curable solvent (reactive diluent). In the latter case, the proportion of polyurethane is limited by the strong increase in viscosity at high levels. Thus, in the

polymers according to the invention a high proportion of polyurethane than

Impact modifier with good handling and

Processability can be achieved. In addition, the polyurethane particles are functionalized with monomers with isocyanate-reactive

Covalently linked to the emulsion polymer groups, as these ensure that the particles during the emulsion in the

be formed resulting polymer. As a result, it is possible to produce emulsion polymer particles which have a uniform morphology.

The polyurethane particles consist of polyurethanes which are prepared by reaction of polyisocyanates with polyols and optionally monomers A with isocyanate-functional groups. Polyisocyanates denote in the context of the invention, low molecular weight compounds which contain two or more isocyanate groups in the molecule. Preference is given to using diisocyanates in the present invention. However, polyisocyanates having three or more isocyanate groups may additionally be added in order to set a suitable property spectrum of elongation at break and tear resistance. The higher the proportion of compounds having three or more functionalities, the higher the tensile strength becomes. However, in order to obtain a suitable elongation at break value, the proportion of polyisocyanates having three or more isocyanate groups should not be greater than about 10% by weight, preferably not greater than 5% by weight, based on the total weight of polyisocyanates.

With regard to the selection of the polyisocyanates, the present invention is not subject to any relevant restrictions. The polyisocyanates which can be used in the present invention include, in particular, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate (4,4'-methylene diphenylene diisocyanate, MDI), 4,4'-dicyclohexyl diisocyanate, 2, 4'-methylenedicyclohexyl diisocyanate, 4,4'-methylenedicyclohexyl diisocyanate, meta- and para-tetramethylxylenediisocyanate, 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), hexamethylene isocyanate, 1,5-naphthylene diisocyanate, dianisyl diisocyanate, di ( 2-isocyanatoethyl) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylate, 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanate (TMDI), triphenylmethane-4,4 ', 4 triisocyanate, tris (4-isocyanatophenyl) thiophosphate and mixtures thereof.

Suitable polyisocyanates can also be obtained, for example, by the reaction of polyhydric alcohols with diisocyanates or by the polymerization of diisocyanates (e.g., isocyanurate structure)

Polyisocyanates can be used, which can be represented by reacting hexamethylene diisocyanate with small amounts of water. These polyisocyanates contain urea groups.

In addition to polyisocyanates can in the implementation of the polyols with the

Polyisocyanates are also used small amounts of monoisocyanates, which act as a chain regulator for the polyisocyanate. However, it is preferable that the amount of the additional monoisocyanates is not more than 10 Mol .-%, in particular not more than 5 mol .-%, based on the total amount of the Isocyanatfunktionalitäten is.

The polyol is preferably a high molecular weight polyol having a statistical molecular weight distribution. As used herein, "high molecular weight polyol" means a polyol having two or more hydroxy groups wherein the weight average molecular weight of the high molecular weight polyol is in the range of> 500 to about 20,000 g / mole. It is preferably in the range of> 500 to 15,000 g / mol,

in particular in the range of> 500 to 10,000 g / mol, and very particularly preferably in the range of> 500 to 5,000 g / mol, measured with

Gel permeation chromatography.

In the above molecular masses, these are to be determined in the context of the present invention using suitable standards over GPC.

Exemplary of high molecular weight polyols are the polyether polyols.

Polyether polyols are polyalkylene ether polyols of the structural formula

wherein the substituent R is hydrogen or an alkyl group having 1-5

Carbon atoms, including mixed substituents, and n is typically an integer between 2-6 and m is 2 to 100 or higher. Preferred polyether polyols are the poly (oxytetramethylene) glycols (= polytetrahydrofurans), poly (oxyethylene) glycols, poly (oxy-l, 2-propylene) glycols and the reaction products of ethylene glycol with a mixture of 1,2-propylene oxide, ethylene oxide and alkyl glycidyl ethers.

Also as high molecular weight polyols can medium molecular weight

Copolyester diols, or linear copolyesters with terminal primary

Hydroxyl groups are used. Your weight-average molecular weight is preferably at 3000-5000 g / mol. Such polyols are available by

Esterification of an organic polycarboxylic acid or a derivative thereof with organic polyols and / or an epoxide. In general, the

Polycarboxylic acids and polyols aliphatic or aromatic dibasic acids and diols.

As the diol in the copolyester diol, alkylglycols such as

Ethylene glycol, neopentyl glycol, or glycols such as bisphenol A,

Cyclohexanediol, cyclohexanedimethanol, caprolactone-derived diols, e.g. the reaction product of epsilon-caprolactone and ethylene glycol, hydroxy-alkylated bisphenols, polyether glycols, such as poly (oxytetramethylene) glycol used. Polyols of higher functionality can also be used. They include, for example, trimethylolpropane, trimethylolethane, pentaerythritol, and also higher molecular weight polyols, such as those made by oxyalkylation of low molecular weight polyols.

As the acid component in the copolyester diol, it is preferable to use monomeric carboxylic acids or anhydrides having 2 to 36 carbon atoms per molecule. Usable acids are e.g. Phthalic acid, isophthalic acid,

Terephthalic acid, tetrahydrophthalic acid, decanedioic acid, dodecanedioic acid. The polyesters may contain minor amounts of monobasic acids, e.g. Benzoic acid, stearic acid, acetic acid and oleic acid. Also usable are higher polycarboxylic acids, such as trimellitic acid.

Another class of high molecular weight polyols that can be used in the present invention are the lactone-type polyesters. These are formed by the reaction of a lactone, e.g. epsilon-caprolactone, with a polyol. The product of a lactone with an acidic polyol can also be used.

In a particularly preferred embodiment, the polyol for the polyurethane (meth) acrylate particles consists of a mixture of at least one high molecular weight polyol and at least one low molecular weight polyol. A low molecular weight polyol is understood according to the invention to mean a compound which has two or more hydroxyl functionalities and has a molar mass of from 50 to 500 g / mol and preferably 50 to 250 g / mol. The molecular weight may be uniform (single compound), or it may be randomly distributed (oligomer), in the latter case below the

Molecular weight is the weight average molecular weight to understand. Preferred as a low molecular weight polyol is one having a uniform molecular weight, wherein the aliphatic diols having 2 to 18 carbon atoms, such as. Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,2-hexanediol and 1,6-hexanediol, and the cycloaliphatic polyols, such as 1,2-cyclohexanediol and Cyclohexanedimethanol are particularly preferred. Likewise usable are polyols with ether groups, such as diethylene glycol,

Triethylene glycol and dipropylene glycol. Exemplary of low molecular weight polyols having more than two hydroxyl groups are trimethylolmethane,

Trimethylolethane, trimethyloipropane, glycerol and pentaerythritol. Most preferably, the low molecular weight polyol used is 1,4-butanediol and 1,3-propanediol. In a further embodiment, as

low molecular weight polyol used 1,4-butanediol or 1,3-propanediol. The molar ratio of the OH groups of the low molecular weight polyol to the OH groups of the high molecular weight polyol is suitably in the range of 0.3 to 1.2.

In addition to polyols, in the reaction of the polyols with the

Polyisocyanates are also used small amounts of monohydric alcohols, which act as monoisocyanates as a chain regulator for the polyisocyanate. However, it is preferred if the amount of additional monoalcohol is not more than 10 mol%, in particular not more than 5 mol%, calculated on the total amount of OH functionalities based on polyols and monoalcohol.

It is likewise possible to use polythiols, polyamines or alkanolamines in addition to the polyols. Aliphatic, alkene or alkynediols which have at least two or more -SH groups, in particular polythiols such as the 2,2'-oxytris (ethanethiol) and di- and tri-groups, are particularly preferably aliphatic thiols. Mercaptoproprionate ester of Poly (oxyethylene) diol thiodigiycols and trioenes. As polyamines, a wide range of compounds can also be used. Examples of suitable linear diamides include, in particular, Jeffami ™ as the

Polyoxypropylene diamines, commercially available as Jeffamine ™ D230, Jeffamine ™ D400 and Jeffamine ™ D2000, and as Jeffamine ™ EDR-148 (a

Triethylene glycol diamine) are available. Examples of alkyl-substituted branched diamines are the 2-methyl-l, 5-pentanediamine, 2,2,4-trimethyl-l, 6-hexanediamine and the 2,4,4-trimethyl-l, 6-hexanediamine. Cyclic diamines may also be used, such as isophoronediamine, for example.

Cyclohexanediamine, piperazine and 4,4'-methylenebis (cyclohexylamine), 4,4'-, 2,4'- and 2,2'-diaminodiphenylmethane, 2,2,4-trimethyl-1,6-hexanediamine, 2 , 4,4-trimethyl-l, 6-hexanediamine and polyoxypropylenediamines. Alkanolamines are compounds that have amine functionalities and hydroxyl functionalities. Further examples of alkanolamines are 2- (methylamino) ethanol and N-methyldiethanolamine. Suitable examples of compounds that have a

Amino group and another group selected from amino and hydroxyl are diamines, Akanoiamine and amine-terminated polyamides or polyethers. Likewise, mixtures of such compounds can be used. It is preferred if the amount of the polyamines, polythiols and alkanolamines is not more than 50 mol%, in particular not more than 20 mol% and particularly preferably not more than 10 mol%, based on the total amount of the OH, NH and SH functionalities in the isocyanate-reactive compounds.

Furthermore, urethane particles having particularly advantageous properties are obtained when the molar ratio of the isocyanate groups of the polyisocyanate to the hydroxy groups of the polyol is in the range of 1.03 to 1.7.

In the polymers, it is expedient if the proportion of the polyurethane particles, based on the total weight of the organic components in the

Polymer is about 5 to 70 wt .-%, preferably 20 to 60 wt .-% and particularly preferably 30 to 50 wt .-% is.

In the polymers, the polyurethane particles can be functionalized with free-radically curable, in particular with vinylic monomers A. These are preferably (meth) acrylates. These polyurethane particles are available by reacting at least one polyisocyanate with at least one polyoi and at least one nukieophii functionalized monomer A, in particular a nukieophii functionalized (meth) acrylic acid ester.

The term "nukieophii functionalized (meth) acrylic acid ester" in the context of this invention means a (meth) acrylic acid ester which carries in its radical derived from the alcohol a nucleophilic functional group which can be reacted wholly or partly with free isocyanate groups. This is preferably a hydroxy, amine or mercapto functionality, more preferably a hydroxy functionality. The latter nucleophil-functionalized (meth) acrylic esters are also referred to as "hydroxyfunctional (meth) acrylic acid esters". By this composition will be

Polyurethane particles are obtained which carry on their surface acrylate functionalities, and thus enter into an interaction with the radically curable monomers in the dispersion. Such particles are also referred to as polyurethane (meth) acrylates.

The term "polyurethane (meth) acrylate" in the context of this invention means a polyurethane whose free terminal isocyanate groups have been completely or partially reacted with a nukieophii functionalized (meth) acrylic acid ester. The isocyanate groups react with the nucleophilic group of the nukieophii functionalized (meth) acrylic ester, e.g. Hydroxy, amino or mercapto, and there are formed terminal ethylenically unsaturated functionalities derived from (meth) acrylates. The term (meth) acrylic acid

here denotes methacrylic acid or acrylic acid, as well as mixtures of these acids. The nukieophii functionalized methacrylic acid esters with the free

Isocyanate groups of the polyurethane react, ie they "cap", are also referred to as "capping reagents" or "capping reagents".

Particularly preferred nukieophii functionalized (meth) acrylic esters are hydroxy-functional (meth) acrylic esters. A "hydroxy-functional (meth) acrylic acid ester" is understood according to the invention to mean a (meth) acrylic acid ester which, after esterification with (meth) acrylic acid, still carries at least one hydroxyl functionality in the residue derived from the alcohol. Different said, it is the ester of a (meth) acrylic acid and a diol or polyol, wherein the diols are preferred.

A particularly preferred group of the "hydroxyfunctional

(Meth) acrylic acid esters "are the hydroxyalkyl (meth) acrylic esters.

Hydroxyalkyl (meth) acrylates which can be used according to the invention are monoesters of (meth) acrylic acid with dihydric, aliphatic alcohols. These

Compounds are known in the art. They can be obtained, for example, by the reaction of (meth) acrylic acid with oxiranes.

With regard to the proportion of nucleophilically functionalized (meth) acrylic acid esters, there are no relevant restrictions within the scope of the present invention. However, it should be ensured that the polyurethane nanoparticles have on average at least one vinyl functionality. The average functionality of free-radically curable groups per nanoparticle is preferably in the range from about 2 to 4, in particular in the range from 2 to 3. In a preferred

In the embodiment, the proportion of nucleophilic groups in the vinylic monomer to be incorporated into the particles is based on the total amount of all the functional groups in the precursors of the polyurethane, i. in particular the OH groups from the polyols, in the range of about 0.1 to 70%, in particular about 25 to 50%. In a further embodiment, the proportion of the functional groups, based on the total amount of all functional groups in the precursors of the polyurethane, is about 0.1 to 10%, in particular 0.5 to 7%.

While the Applicant does not cite any particular theory in this regard, it is believed that the functionalized nanoparticles form "nano-centers" that are integrated (ie, polymerized in) during the polymerization of the free-radically curable monomers into classical acrylic / polyurethane dispersions are usually considered physical

Mixtures in which there are essentially no covalent bonds between the polyurethane constituents and acrylates (chain transfer may also lead to a slight extent in the polymerization of the acrylate fractions to link acrylates and polyurethanes). By the

However, functionalization of the polyurethane particles, the particles are integrated at least proportionately in the acrylate matrix. As a result, the mechanical technological properties compared to non-covalently linked polyacrylate / polyurethane hybrids significantly improved.

In a further embodiment, excess isocyanate functionalities in the polyurethane particles can also be reacted with monohydric alcohols, such as methanol, ethanol, n- or iso-propanol, butanol, etc., so that the resulting polyurethane particles do not react with respect to the radically curable monomer B groups exhibit. In some cases, such polyurethane particles can contribute to a further stabilization of the emulsion. If monohydric alcohols are used to react the remaining isocyanate functionality in the polyurethane particles, instead of the above

Quantity restrictions for monohydric alcohols as chain regulators the

To set quantitative limits for vinylic monomers to be included in the particles.

The functionalized polyurethanes, which are then subjected to emulsion polymerization with free-radically curable monomers B, have an average molecular weight Mn of about 3,000 g / mol to 800,000 g / mol and preferably from 3,000 g / mol to 600,000 g / mol. The functionalized polyurethanes preferably have high average molecular weights, since this is advantageous for the chemical resistance of the particles. In addition, high molecular weight functionalized polyurethanes also have better mechanical and technological properties, such as improved adhesion, adhesiveness, tensile and tear strength, and excellent ductility. For this reason, the average molecular weight of the functionalized polyurethanes is preferably in the range from 100,000 to 800,000 g / mol,

in particular 200,000 - 600,000 g / mol.

The polymers according to the invention are by emulsion polymerization of the polyurethane particles described above, the free-radically curable

Have functionalities, with at least one free-radically curable monomer B available. In this case, the polyurethane particles have an average diameter of less than 40 nm, preferably a mean diameter of less than 20 nm and in particular a mean diameter of less than 10 nm. While the Applicant does not invoke any particular theory, the small particle size that the resulting polymer has a favorable transparency. Depending on the polyols and polyisocyanates included in the polyurethane particles, the polyurethane particles may also function as an emulsifier for free-radically curable monomers in emulsion polymerization of these monomers without the need for modification of the pendant anionic polyurethane.

With regard to the radically curable monomers B to be used, the present invention is not subject to any relevant restrictions. However, it is preferred if, as the radically curable monomer B, a vinyl monomer,

in particular styrene and substituted styrenes, such as substituted styrenes having an alkyl substituent in the side chain, e.g. alpha-methylstyrene and alpha-ethylstyrene, substituted styrenes having an alkyl substituent on the ring, such as vinyltoluene, halogenated styrenes, such as

Monochlorostyrenes, dichlorostyrenes, tribromostyrenes or tetrabromostyrenes.

Further advantageously used free-radically curable monomers B are

Vinyl acetate, vinyl chloride and vinylidene chloride. A preferred free-radically curable monomer is vinylidene chloride (1,1-dichloroethylene). In a further preferred embodiment, the radically curable monomer B comprises dienes, in particular isoprene, butadiene or a mixture thereof.

In other cases, it is preferred that the free-radically curable monomer B is (meth) acrylate. These are to be understood in the context of the invention, both methacrylates and acrylates. The (meth) acrylates may have one or more double bonds. (Meth) acrylates which have two or more double bonds are referred to in the context of the invention as polyvalent (meth) acrylates and serve above all to establish a desirable degree of crosslinking. The alcohol-derived residue of the (meth) acrylates may contain heteroatoms, for example in the form of ethers, alcohols, carboxylic acids, esters or urethane groups.

The radical curable monomer B may be used in the form of a single compound or two or more radical curable monomers. Particularly preferred free-radically curable monomers B in the context of the invention include alkyl (meth) acrylates which are derived from saturated

Alcohols such as methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acryiate, n-propyl (meth) acrylate, n-, iso- or tert-butyl (meth) acrylate, pentyl (meth) acrylate , n-hexyl (meth) acrylate, n-octyl (meth) acrylate, n-decyl (meth) acrylate, isooctyl (meth) acrylate, tetra-decyl (meth) acrylate, phenoxyethyl (meth) acrylate, allyl (meth ) acrylate, glycidyl (meth) acrylate, neopentyl (meth) acrylate, isobornyl (meth) acrylate, hexanedioic diacrylate (HDDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), cyclohexyl (meth) acrylate, tert-butyl (meth) acrylate , Tetrahydrofurfuryl (meth) acrylate, maleic acid mono-2- (meth) acryloylmethyl ester, 7,7,9-trimethyl-4,13-dioxo-3,14-dioxa-12-diazahexanecan-1, 16-dioledi ( meth) acrylate, 3- [2 - ((meth) acryloyloxy) ethoxycarbonyl] -propionic acid or mixtures thereof. Most preferred free-radically curable monomers B are methyl acrylate (MMA), 2-phenoxyethyl methacrylate (POEMA), isobornyl acrylate (IBOA), 2-ethylhexyl acrylate (2-EHA), and tetrahydrofurfuryl methacrylate (THFMA).

In addition, vinyl ethers may also be copolymerized in, e.g. 2-ethylhexyl vinyl ether, 4-hydroxybutyl vinyl ether, butanediol divinyl ether, cyclohexyl vinyl ether, diethylene glycol divinyl ether, dodecyl vinyl ether, isobutyl vinyl ether (bar 0.1% DEA), N-butyl vinyl ether, octadecyl vinyl ether, triethylene glycol divinyl ether and tert-butyl vinyl ether.

In the emulsion polymerization with which the polymer according to the invention is obtainable, it is possible to add conventional emulsifiers, for example alkyl sulfate salts such as sodium dodecyl sulfate, alkyldiphenyl oxide disulfonates, ethoxylates of secondary alcohols, ethylene oxide /

Propylene oxide copolymers, diphenol ethoxylates or polyether phosphate esters.

Other conventional emulsifiers used in emulsion polymerizations

can be included, are familiar to the expert. Also, polymerizable emulsifiers such as e.g. Sodium vinyl sulfonate can be used.

The addition of an emuigator is not mandatory. When using suitable polyols (for example, long-chain polyoxyalkylene polyols) in the polyurethane, the polymerization can be carried out in the absence of additional emulsifiers be carried out as an emulsifying effect is ensured on the one hand by the nano-structure of the polyurethane particles and on the other by the interaction of the polyol chains with water. Alternatively, the use of additional emulsifiers can be reduced compared to conventional emulsion polymerizations.

The polymerization is conveniently started by conventional polymerization initiators, which are preferably water-soluble and after

Energy intake to form free radicals. Illustrative of such initiators are hydrogen peroxide, sodium persulfate, potassium persulfate and

Ammonium persulfate or corresponding peroxodisulfates and tert-butyl hydroperoxide, wherein the catalyst is useful in amounts ranging from 0.01 wt .-% to 3 wt .-%, preferably 0.01 to 1 wt .-%, based on the total solids content the emulsion is to be used.

As the initiator, a single compound may be used or a combination with reducing agents such as sodium formaldehydesulfoxylate, iron salts,

Sodium dithionite, sodium bisulfite, sodium sulfite or sodium thiosulfate, which act as redox catalysts and can be used in amounts ranging from 0.01 to 3 wt.%, Preferably 0.01 to 1 wt.%, Based on the total solids content of the emulsion , The free-radical initiators can be completely added to the aqueous emulsion at the beginning of the polymerization or added in several batches.

The polymerization is usually carried out at a pH of between 2 and 7, preferably 3 to 5. In order to remain in this pH range, it may be appropriate to work in the presence of a buffer system, such as alkali metal acetates, alkali metal carbonates or alkali metal phosphates. Also regulators, such as mercaptans, aldehydes, chloroform,

Ethylene chloride and trichlorethylene, are added.

The polymer can with regard to its proportion of free-radically curable

Monomers B have functional groups, in particular hydroxyl or carboxyl groups, which are available for subsequent crosslinking. Such crosslinking can be achieved by self-crosslinking or by adding external crosslinking agents such as melamine resins, polyaziridines, polycarbodiimides, hydrophobized and / or hydrophilic polyisocyanates.

The present invention also relates to a process for preparing a polymer as described above, comprising a) the reaction of at least one polyisocyanate with at least one polyol and optionally at least one free-radically curable monomer A with isocyanate-reactive groups in at least one free-radically curable monomer B to polyurethane particles with an average diameter of less than 40 nm, preferably less than 20 nm and more preferably less than 10 nm, and an average number of radically curable functionalities in the range of 2 to 4, preferably 2 to 3, and b) emulsion polymerization of the under a ) obtained product.

It has proven to be advantageous over comparable prior art processes when the polyisocyanate in the radically curable monomer B, which in this case acts as a reactive diluent, is reacted with the polyols and the radically curable monomer A with isocyanate-reactive functionality , In this case, the free-radically curable monomer which acts as a reactive diluent expediently has no functional groups which react with isocyanates. This procedure has the advantage that, on the one hand, no additional solvent has to be used. On the other hand, the production of polyisocyanates in water is always associated with a degree of hydrolysis of the isocyanates, which is due to the formation of

Urea linkages in the resulting polymer negative on the

Properties, especially in unfavorable resistance to outdoor weathering or UV radiation, can affect. By the polymerization in the radically curable monomer, this side reaction is suppressed and the properties of the polyisocyanate can be better adjusted.

Preferably, the reaction a) is carried out in a stirred tank at a Rührerumfangsgeschwindigkeit of at least 5 m / s, wherein the ratio of stirrer diameter to vessel diameter 0.3 to 0.80 and the distance of the stirrer from the bottom of the vessel from 0.25 to 0.5 times the stirrer diameter. The geometry of the stirrer and its speed can be expertly designed by the person skilled in the art on the basis of the above information. However, it has been found to be expedient for the stirrer peripheral speed to be in the range of 100 to 500 rpm, preferably 150 to 300 rpm. Alternatively, the method according to the present invention can be advantageously designed by the stirrer peripheral speed being at least 12 m / s. In addition, it is preferred that a dispersing disk, a Turrax stirrer (eg Unidrive X 1000 D CAT, Zipperer GmbH Co. with G20 20 mm V shank) or a KPG stirrer is used as the stirrer.

In the emulsion polymerization with the polymer of the invention produced in step b), it is expedient to polymerize the radically curable monomer B with the aid of an initiator, as listed above.

It is also advantageous if the reaction of the polyisocyanate with the polyol in step a) of the process is carried out in the presence of a catalyst which may be selected from tertiary organic amines and / or organic tin compounds. In particular, the use of

Dibutyltin laurate as a catalyst particularly useful.

The emulsion polymers according to the invention preferably have a particle size of the secondary particles obtainable from the emulsion polymerization in the range from about 50 to about 150 nm, more preferably from about 70 to about 120 nm. In these secondary particles, the polyurethane nanoparticles are involved in the form of inclusions.

Polymers obtainable by emulsion polymerization have a very high market importance and are especially established for use in adhesives, textiles and coatings. According to the process of the present invention, such polymers can be prepared much easier, less expensive and more targeted, in particular the use of organic

Solvents such as acetone is dispensable. Therefore, another aspect of the method described above is that the use of organic solvents, in particular acetone is dispensed with. Due to the adhesive strength, the polymers of the invention are particularly suitable as an adhesive. Accordingly, a further aspect of the present invention relates to the use of a polymer as described above as an adhesive, in particular as a dispersion adhesive. to

Formulation of the adhesive, the polymer can be used in pure form (i.e., as described above), or with other reactive adhesives on an aqueous basis or with reactive adhesives on reactive adhesive base, in particular (meth) acrylate-based added. In addition, a use of the polymers as adhesive layer on adhesive tapes is the subject of the present invention.

Another aspect of the present invention relates to the use of the above-described polymers as a lacquer or constituent of a lacquer.

For example, polymers of the invention in the wood or

Furniture coating can be used as a primer and / or topcoats (TopCoats). In this industry, the highest level of transparency is required for clearcoat systems (ie.

no obscuring the wood grain) sought to be a very good

To achieve wood firing. The term "Holzanfeuerung" is the

Color depression referred to, which occurs during the wetting of the wood surface through the coating material and permanently emphasizes the wood grain. When inorganic nanoparticles are used, turbidity is often visible from an effective concentration.

With the polymers according to the invention and aqueous paints prepared therefrom, moreover, primed or unprimed plastics such as. ABS, AMMA, ASA, CA, CAB, EP, UF, CF, MF, MPF, PF, PAN, PA, PC, PE, HDPE, LOPE, LLDPE, UHMWPE, PET, PMMA, PP, PS, SB, PUR, PVC, RF, SAN, PBT, PPE, POM, PUR-RIM, SMC, BMC, PP-EPDM and UP (curve designations according to DIN 7728 Tl) are coated. The coating of plastics serves one

Improvement of the adhesion and scratch resistance of the paint systems used.

In addition, the paint systems must have a certain elasticity to remain crack-free at high and low temperatures at impact stress (eg bumpers). Another area of application is, for example, PVC and linoleum floors. For embossable linoleum floors, the prior art is UV-curing

Polyurethane dispersions used. In such applications, the polymers according to the invention are used to improve the abrasion resistance or service life.

Automotive paints (primers, fillers, etallic basecoats, topcoats or clearcoats) are mainly applied by spraying. As a rule, such paints are shiny. Such high quality surfaces are expected to have a clear, brilliant appearance. The use of inorganic and nanoscale fillers or nanoparticles in clearcoats leads to slightly milky / cloudy phenomena. This effect is referred to as a haze or "haze." The haze only occurs in high-gloss surfaces

Polymers are used to prevent such haze and, moreover, for improvements, "scrub brush resistance" to micro-scratching.

In the field of industrial coatings, a wide variety of crosslinking processes are used (ΙΚ-oxidative, IK-melamine resin crosslinking, IK-blocked

Polyisocyanates, 2K-polyisocyanate, 1K self-crosslinking, 1K physically

drying). At present, solvent-dilutable paints dominate this field of application. However, water-based paints are becoming increasingly important. The

Polymers according to the invention can be functionalized in such a way that the above-mentioned crosslinking processes are possible. They are therefore compatible with appropriate formulation with melamine resins, blocked and unblocked polyisocyanates.

Other important fields of application are single-coat primers, single-coat paints and clearcoat systems. The polymers of the invention are also for

Corrosion protection coatings suitable. Those used in the prior art

Primary dispersions (polyacrylates) have the disadvantage that no higher gloss levels can be achieved with them. Finally, dispersions of the invention can be further processed on films. Of particular interest are in particular films based on polyvinylidene chloride, as barrier films for food and

Pharmaceutical packaging can be used. Another field of application for the polymers according to the invention are corrosion protection applications.

The varnishes and adhesives described above may be formulated with conventional additives depending on their use. Exemplary but not exhaustive for such additives are coalescing agents such as ethylene glycol, defoamers, for example based on polyether siloxane copolymers, wetting agents, for example based on polyether-modified siloxanes and thickeners, for example based on polyurethanes. In addition, it may be expedient to adjust the pH of the emulsion so that the most stable possible emulsion is obtained. A suitable pH in the context of the present invention is in the range of 7 to 9.

Another aspect of the present invention relates to the application of a polymer according to the invention to a textile.

Finally, another aspect of the present invention relates to

Use of polymers according to the invention for the production of films and cast films, wherein the polymers can be used either alone or as a mixture with other components.

The uses described above may include applying the polymers of the invention to a corresponding substrate and optionally curing the dispersion by physical drying. This can be done for example by applying a vacuum or by heating. The person skilled in the art is familiar with further alternatives for physical drying, which require no further explanation here.

The polymers according to the invention described above are characterized in many applications by advantageous properties, in particular a desirable transparency, high impact strength and elongation at break and good adhesion to materials such as PVC, glass, wood and metal. The degree of crosslinking can be advantageously adjusted within the scope of the invention, so that sufficient flowability is ensured. In addition, there is a good opportunity for the specific application desirable properties to realize by the possible high flexibility in terms of usable acrylates, methacrylates, diols and diisocyanates.

In addition, by selecting suitable starting materials, an addition of dispersion stabilizers can be avoided. Because of these properties, such polymers are highly interesting in a variety of industrial applications.

In the following, the present invention will be illustrated in more detail by way of some examples, which, however, are not relevant to the determination of the scope of the present invention.

Examples:

Example 1: Synthesis of the primary particles in the reactive diluent

The experiments were carried out in a vacuum circuit dissolver type V KDV 30-3.0 from Niemann (D-49326 mile). The container size, disk diameter, number of revolutions and temperature used are given in Table 1.

The synthesis was carried out as follows: 0.2692 mol of diisocyanate (TM DI) and 2.31 mol of (reactive) diluent (methyl methacrylate (MMA) or vinylidene chloride (VCD)) are weighed out on an overhead balance and are heated at 60.degree C or 20 ° C at the specified speed of rotation for 2 h. Subsequently, 0.072 mol of polyol (Lupranol VP 9358 (PPG), PTHF 2000, Dynacoll 7250), 0.085 mol of chain extender (1,4-butanediol) and optionally 1.36 mol

(Reactive) diluent (MMA, VCD) added. The mixture was heated slightly and then added dropwise for 1 h into the reactor with the aid of a dropping funnel heated to 60 ° C. Then 0.728 mmol of catalyst (DBTDL or DABCO) were added to the reaction mixture and stirred for a further hour at 60 ° C / 20 ° C. This is followed by the determination of the free isocyanate groups in accordance with DIN EN 1242.

For the "capping", an equimolar amount of capping reagent (hydroxyethyl methacrylate (HEMA), methanol, or to the determined isocyanate content

Hydroxyethyl acrylate (HEA)) was added and the mixture was cooled to 23 ° C.

After synthesis and endcapping, 25 ppm of 5% hydroquinone solution was added as a stabilizer.

Table 1 :

When samples 3 to 6 were stored at 23.degree. C., it could be observed that a slight sediment forms in the clear, slightly viscous product. The sediment is significantly lower than the polyurethane content (5 wt .-%) of the samples. The VDC-based products with 5% polyurethane content could be produced with different polyols. Example 2: Preparation of Emulsion Polymers

In a dropping funnel, the emulsion of the monomers is generated by stirring. 97.44 g of water, 13.33 g of sodium dodecyl sulfate (15%) and 200 g of the respective starting material are weighed in (emulsion feed). In a second dropping funnel, the initiator is dissolved in water. 39.00 g of water and 1.0 g of sodium peroxodisulfate are weighed in (initiator). In the nitrogen-purged reactor now 55.90 g of water, 15.54 g

Emulsion feed and 4 g initiator feed submitted. This mixture is then heated with stirring to 85 ° C. This starts the polymerization. After 5 minutes at 85 ° C, the contents of the two dropping funnels are added uniformly in 1.5 hours with stirring in the reactor. The temperature must be maintained very accurately by cooling to 85 ° C +/- 1 ° C. After the end of the feed, the temperature is maintained at 85 ° C. for a further 1 h and then cooled.

In the synthesis, about 400 g of a 50.2% aqueous dispersion and 5 g of coagulate were formed. The particle size has been adjusted by the amount of emulsion in the original to 190 nm diameter with narrow distribution.

If you want to change the particle size, so you can change the amount of initial charge in the polymerization, or the Emulgatorkonzentration or give additional emulsifier in the template.

The conditions for various emulsion polymerizations are shown in Table 2 below. Table 2;

In the comparative and the two samples according to the invention, a viscous, but flowable, milk-colored liquid was obtained. Small amounts of (polymeric) solid (few grams) formed could be easily separated and posed no problems on the scale described.

Paint formulations were formulated from the aqueous dispersions of the comparative sample and the inventive samples 8 and 9, and corresponding paint films were produced. Table 3 lists the formulations used (parts by weight, 100%). To the stability and compatibility of the used

To increase dispersions, the dispersions were adjusted to pH 8-9 with ammonia. Table 3: prepared paint formulations

1 coalescing agent for the filming of the dispersions, 2 antifoams in the form of a polyethersiloxane copolymer, silicic acid containing silicic acid, 3 substrate wetting agents in the form of a solution of a polyether-modified siloxane, 4 polyurethane thickeners.

Due to the high glass transition temperature, the comparative dispersion required, as expected, the highest coalescing agent content. The watery

Formulations were applied to black PVC film, glass and wood (beech veneer) with a box wiper (200 μm wet application). After the order, the formulations filmed foam-free. Thereafter, the coated substrates at 40 ° C (circulating air temperature) in the laboratory oven for 8

Hours dried. Subsequently, the paint films were different Subjected to tests. The results of these tests are shown in Table 4 below.

Table 4:

* The term "wood firing" refers to the color deepening which occurs when the wood surface wets through the coating material and permanently emphasizes the wood grain (Prieto / Kiene: Fachbuch "Holzbeschichtung", Coatings Compendien, Curt Vincentz-Verlag Hannover, 2007)

As can be seen from Table 4, the aqueous dispersions paint 2 and paint 3, compared to the comparative sample paint 1 to improve the adhesion to glass and PVC film. In the "Chemical Test", based on DIN 68861 Part 1 B / C, the coated surfaces with Lacquer 2 and Lacquer 3 also tend to perform better than the Comparative Sample Lacquer 1. The best chemical resistance (water, alcohol) has the Dispersion Lacquer 3 , At the same time, this dispersion also shows the lowest pendulum attenuation values (softer than varnish 1 and varnish 2, the aqueous dispersions varnish 1 and varnish 2 show very similar oscillation damping values). The highest gloss level based on DIN EN ISO 1522 is shown by the formulations according to paint 1 (38) and paint 2 (46). When comparing the "tempering" on beech (veneered) shows surprisingly, the dispersion varnish 3 a particularly good "start-up", which exceeds the current level of the known aqueous polyacrylate.

The results of the experiments have shown that the modification of aqueous polyacrylate dispersions with polyurethane polymers (nanoscale) leads to coating films with improved property profiles. The adhesion, chemical resistance (water, alcohol) and the

"Onfeuerung" be improved by wooden substrates.

Claims

claims

1. A polymer can be prepared by a process comprising a) reacting at least one polyisocyanate with at least one polyol and optionally at least one free-radically curable monomer A with isocyanate-reactive groups in at least one free-radically curable monomer B to polyurethane particles having an average diameter of less than 40 nm , preferably less than 20 nm and more preferably less than 10 nm, and an average number of free-radically curable

Functionalities in the range of 2 to 4, preferably 2 to 3,

b) emulsion polymerization of the product obtained under a).

2. A polymer according to claim 1, characterized in that the at least one radically curable monomer A with isocyanate-reactive groups a vinyl monomer with isocyanate-reactive groups, preferably a (meth) acrylate with isocyanate-reactive groups.

3. Polymer according to one of claims 1 to 2, characterized in that the proportion of the polyurethane particles in the composition according to step a) 20 to 70% by weight, based on the organic components of the composition.

4. A polymer according to any one of claims 1 to 3, characterized in that the radically curable monomer B is a vinyl monomer which is unreactive to isocyanates, preferably a (meth) acrylate, a mixture of (meth) acrylates or vinylidene chloride.

5. A polymer according to any one of claims 1 to 4, characterized in that the molar ratio of the isocyanate groups to the hydroxyl groups from the polyol in step a) is 1.03 to 1.7.

6. Polymer according to one of claims 1 to 5, characterized in that the polyol is a high molecular weight polyol with a weight average of

Molecular weight (Mw) of> 500 to 20,000 g / mol.

7. Polymer according to claim 6, characterized in that the

high molecular weight polyol is selected from Poiyetherpolyolen, in particular polytetrahydrofurans, and polyester polyols.

8. Polymer according to claim 6 or 7, characterized in that in addition to the high molecular weight polyol, a low molecular weight polyol having a molecular weight of 50 to 500 g / mol is used, preferably 1,4-butanediol, 1,3-propanediol or a mixture thereof.

9. Polymer according to claim 8, characterized in that the molar ratio of the OH groups of the low molecular weight polyol to the OH groups of

high molecular weight polyol 0.3 to 1.2.

10. A process for preparing a polymer as described in claims 1 to 9, comprising a) the reaction of at least one polyisocyanate with at least one polyol and at least one free-radically curable monomer A with isocyanate-reactive groups in at least one radically curable monomer B to polyurethane particles with an average diameter of less than 40 nm, preferably less than 20 nm and more preferably less than 10 nm, and an average number of free-radically curable functionalities in the range of 2 to 4, preferably 2 to 3, and b) emulsion polymerization of the under a ) obtained product.

11. The method according to claim 10, characterized in that the reaction a) is carried out in a stirred tank at a Rührerumfangsgeschwindigkeit of at least 5 m / s, preferably at least 12 m / s, the ratio of stirrer diameter to vessel diameter 0.3 to 0, Is 80 and the distance of the stirrer from the bottom of the vessel is 0.25 to 0.5 times the stirrer diameter.

12. The method according to claim 10 or 11, characterized in that the

Emulsion polymerization with the aid of a water-soluble radical initiator, in particular with hydrogen peroxide, sodium persulfate, potassium persulfate,

Ammonium persulfate corresponding Peroxodisulfaten or tert-butyl hydroperoxide.

13. Use of a polymer according to any one of claims 1 to 9, as an adhesive, preferably as a dispersion adhesive, as part of an adhesive or

Dispersion adhesive or as part of an adhesive tape.

14. Use of a polymer according to one of claims 1 to 9 for

Coating of a substrate, preferably as a lacquer or constituent of a lacquer or for coating textiles.

15. Use of a polymer according to one of claims 1 to 9 as a film or cast film.

16. Use of a polymer according to any one of claims 1 to 9, comprising applying the dispersion to a substrate followed by a physical drying, in particular a convection drying, and optionally a crosslinking.

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