TW201341416A - Low-solvent polyacrylate copolymer dispersions - Google Patents

Abstract

The present invention relates to an aqueous secondary copolymer dispersion comprising a copolymer (P) synthesized from a mixture of free-radically polymerizable monomers (M) comprising (M1) cycloaliphatic esters of acrylic and/or methylacrylic acid; (M2) vinyl esters of aliphatic carboxylic acids; (M3) hydroxy-functional, free-radically polymerizable monomers; (M4) carboxyl-functional, free-radically polymerizable monomers and (M5) hydroxyl- and carboxyl-free (meth)acrylic esters having C1 to C12 hydrocarbon radicals in the alcohol moiety and/or vinylaromatics. The mixture further comprises glycidyl esters of aliphatic carboxylic acids. The invention also relates to a method for the production of such a dispersion, to the use of the dispersion as a coating and as a binder in 2K polyurethane coatings.

Description

Low solvent polyacrylate copolymer dispersion

The present invention relates to an aqueous secondary copolymer dispersion comprising a copolymer (P) synthesized from a mixture of radical polymerizable monomers (M) comprising (M1) acrylic acid and/or methyl group a cycloaliphatic ester of acrylic acid; (M2) a vinyl ester of an aliphatic carboxylic acid; (M3) a hydroxy functional, radically polymerizable monomer; (M4) a carboxyl functional group, a radically polymerizable monomer, and (M5) in the alcohol moiety There are hydroxyl-free and carboxyl-free (meth) acrylates and/or vinyl aromatics having a C1 to C12 hydrocarbon group. The mixture further includes a glycidyl ester of an aliphatic carboxylic acid. The invention also relates to a method of making the dispersion, and to the use of a dispersion as a coating and as a binder in a 2K polyurethane coating.

Aqueous secondary copolymer dispersions are widely used in the art as coating materials and adhesives. In this regard, the term "secondary dispersion" refers to such aqueous dispersions which are generally polymerized in a homogeneous organic medium without prior addition of a foreign emulsifier and thereafter redispersed in an aqueous medium.

For example, US 2007/282049 A1 relates to a novel aqueous secondary copolymer dispersion, to a process for its preparation and to an advanced coating for the manufacture of especially wood. The dispersion comprises a copolymer (P) synthesized from a mixture of radical polymerizable monomers (M) comprising (M1) a cycloaliphatic ester of acrylic acid and/or methacrylic acid and also (M2) a vinyl ester of an aliphatic carboxylic acid.

No. 6,399,691 describes a hydroxy-functional copolymer P in the form of a dispersion and/or a solution of water obtained by successively carrying out process steps A to D: A) initially introducing a hydrophobic polymer containing a hydroxyl group into a reaction vessel, B) will initiate Introducing the ingredients into the container, C) subsequently polymerizing the hydrophobic monomer mixture containing the hydroxyl groups in the container D) A hydrophilic monomer mixture containing a hydroxyl group and an acid group is then polymerized in a vessel. The invention also relates to a process for preparing a copolymer P following the previously proposed procedure, and to a coating composition comprising such a copolymer P and one or more crosslinking agents.

US 2005/165145 A1 relates to a process for preparing a copolymer dispersion comprising A) one or more vinyl monomer mixtures [which contain a) OH-free (meth) acrylate and/or vinyl aromatic, b) a hydroxy-functional vinyl monomer and/or a hydroxy-functional (meth) acrylate, c) a radical copolymerizable ion and/or a latent ionic monomer, and d) a compound component a) to c) capable of free radicals Copolymerization as the case may further be a monomer] in the presence of a compound according to formula (I) e) wherein R1 is an aliphatic, araliphatic or aromatic group having from 1 to 18 carbon atoms, R2 is H Or CH ₃ , R ₃ , R 4 are the same or different aliphatic radicals having 1 to 7 carbon atoms, n is 1 to 4] undergo radical polymerization; then the dispersion is obtained before or after the neutralizing agent C) is added to the water. Copolymer B). The resulting dispersion can be used to coat a substrate.

US 2004/034164 A1 relates to a binder dispersion comprising at least one copolymer (P) comprising a carboxylic acid and/or carboxylate group. The copolymer (P) comprises a structural unit of a carboxyl group-free (meth) acrylate having a cycloaliphatic structure, and at least 25 mol% of the carboxylic acid group of the copolymer (P) in the dispersion is present in a neutralized form of triethanolamine. . Aqueous adhesives can be used to coat aqueous coating materials for substrates.

Due to environmental, health and safety considerations, it is desirable to have a copolymer dispersion with a coating purpose and with as low an organic (co) solvent as possible without compromising coating properties. The present invention has the goal of providing such a low solvent dispersion.

According to the invention, this object is achieved by an aqueous secondary copolymer dispersion comprising a copolymer (P) synthesized from a mixture of radical polymerizable monomers (M), the monomer (M) comprising : (M1) a cycloaliphatic ester of acrylic acid and/or methacrylic acid (M2), a vinyl ester of an aliphatic carboxylic acid (M3), a hydroxyl functional group, a radically polymerizable monomer (M4), a carboxyl functional group, a radically polymerizable monomer (M5) a hydroxyl group-free and carboxyl group-free (meth) acrylate and/or vinyl aromatic group having a C1 to C12 hydrocarbon group in the alcohol moiety, wherein the mixture further comprises a glycidyl ester of an aliphatic carboxylic acid.

The dispersion according to the invention results in a coating having a high gloss and high hardness compared to a dispersion having a high (about 8% by weight) (co)solvent. Without wishing to be bound by theory, it is believed that the glycidyl ester acts at least as a reactive diluent.

For the purposes of the present invention, acrylic acid or methacrylic acid is also defined as (meth)acrylic acid.

Suitable monomers (M1) are, for example, cyclohexyl (meth)acrylate, cyclohexyl (meth)acrylate substituted with an alkyl group, 4-tert-butylcyclohexyl (meth)acrylate, (methyl) As the decyl acrylate, isodecyl (meth) acrylate, it is preferred to give isodecyl acrylate and/or isodecyl methacrylate, and it is particularly preferable to give isodecyl methacrylate. It is also possible to use a mixture comprising isodecyl acrylate and isodecyl methacrylate with other monomers (M1). The monomer (M1) different from isodecyl acrylate and isodecyl methacrylate may be used in an amount of less than 10% by weight, based on the sum of (M1) to (M5).

Suitable monomers (M2) are esterification products of vinyl alcohol with linear or branched aliphatic carboxylic acids, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl octanoate, Vinyl citrate, vinyl dodecanoate (vinyl laurate) or vinyl stearate.

Suitable hydroxy-functional monomers (M3) comprise an ethylenically unsaturated hydroxyl-containing monomer, such as a hydroxyalkyl ester of an unsaturated carboxylic acid, preferably having from 2 to 12, preferably from 2 to 6 carbon atoms in the hydroxyalkyl group. Hydroxyalkyl (meth)acrylate. Examples of particularly preferred compounds are 2-hydroxyethyl (meth)acrylate, hydroxypropyl isomeric (meth)acrylate, 2-, 3- and 4-hydroxybutyl (meth)acrylate, and (meth)acrylic acid. Hydroxyhexyl ester.

Suitable carboxyl functional free-radically polymerizable monomers (M4) are ethylenically unsaturated monomers containing carboxylic acid or carboxylic anhydride groups, such as acrylic acid, methacrylic acid, β-carboxyethyl acrylate, crotonic acid, fumaric acid A monoalkyl ester of maleic anhydride, itaconic acid, or a dibasic acid or anhydride (for example, a monoalkyl maleate). Acrylic and / or Methacrylic acid is preferred.

The hydroxy-free- and carboxy-free-free monomers (M5) used are acrylates and methacrylates having 1 to 12 carbon atoms in the alcohol moiety of the ester group. The alcohol moiety is preferably aliphatic and can be linear or branched.

Examples of suitable monomers for the component (M5) are methyl (meth)acrylate, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, isobutyl ester, tert-butyl ester, isomeric amyl ester, hexyl ester, 2-ethylhexyl ester, octyl ester and dodecyl ester. Particularly suitable for vinyl aromatic is styrene, optionally substituted styrene and vinyl toluene. Preferred monomers (M5) are methyl (meth)acrylate, n-butyl ester, isobutyl ester, tert-butyl ester and 2-ethylhexyl acrylate and styrene.

Optionally, monomer (M6) such as ethionylethyl methacrylate, acrylamide, acrylonitrile, vinyl ether, methacrylonitrile or vinyl acetate may also be present. Further, it is possible to use a monofunctional polyalkylene oxide having a molecular weight of 200 to 3000 g/mol, preferably 350 to 1000 g/mol, or an esterified (meth)acrylic acid, which is suitable as a nonionic hydrophilic group. Suitable alkylene oxides comprise the preferred ethylene oxide or a mixture of ethylene oxide and propylene oxide. However, the hydrophilization of the copolymer preferably takes place by means of an ion-based means monomer (M4).

The ratio of the synthetic components (M1) to (M6) may be selected such that the copolymer (P) has an OH value of 35 to 200 mg KOH/g, preferably 50 to 125 mg KOH/g solid, and an acid value of 10 to 50 mg KOH/ g, preferably 15 to 30 mg KOH / g solids. The acid number is determined as stated in DIN 53402. The OH number is determined as stated in DIN 53240.

The preparation of the copolymer (P) can in principle be carried out in the organic phase by means of conventional free radical polymerization methods. The copolymer (P) is preferably prepared in a multistage operation of the kind already described in EP-A 0 947 557 (p. 31.2 to p. 41.15) or EP-A 1 024 184 (p. 21.53 to p. 41.9). In this operation, a hydrophobic monomer mixture (M1) having no acid group or a low acid group content is first metered in, and then a more hydrophilic monomer mixture (MII) containing an acid group is metered in at a later point in the polymerization, containing The more hydrophilic monomer mixture (MII) of the acid group does not contain monomers of the types (M1) and (M2).

The copolymerization is carried out usually at 40 to 180 ° C, preferably 80 to 160 ° C. Suitable for The initiator (I) for the polymerization reaction comprises an organic peroxide such as di-tert-butyl peroxide, for example, or a third butyl peroxy-2-ethylhexanoate and an azo compound. The dosage used will depend on the desired molecular weight. For reasons of operational reliability and ease of handling, it is also possible to use a peroxide initiator in the form of a solution in a suitable type of organic solvent.

The rate of addition of initiator (I) in the process of the invention can be controlled so that it continues until the monomer feed (M) is complete, and the amount of solvent in steps one and two is selected such that the organic solvent content is less than 5% by weight.

It is preferred to calculate the amount of the components so as to cause a mass ratio (V): (M) is 1:9 to 3:7 and (M1): (MII) is 9:1 to 6:4, and particularly good mass ratio (V): (M) is 1.2:8.8 to 2:8 and (M1): (MII) is 8.5:11.5 to 7:3.

Free radical polymerization can be carried out in the presence of a solvent or solvent/water mixture charged in the reaction vessel. Suitable organic solvents include any solvent known in the art of lacquering, preferably those which are typically employed as cosolvents in such aqueous dispersions, such as alcohols, ethers, ethers containing alcohols, esters, ketones or non-polar hydrocarbons, or A mixture of solvents. The solvent is used in an amount of from 0% by weight to 5% by weight, preferably from 0.1% by weight to 5% by weight, based on the level of the whole dispersion.

It is further possible to prepare a copolymer by using a hydrophobic copolymer as a preliminary feed by the method of EP-A 1 024 184.

Instead of a multi-stage polymerization process, it is also possible to carry out the inventive process (gradient polymerization) continuously, that is to say that the monomer mixture is added to the varying composition, and the hydrophilic (acid-functional) monomer fraction feed is higher at the end than at the beginning.

The number average molecular weight Mn of the copolymer (P) can be controlled by specific selected operating parameters, such as molar monomer/initiator ratios, such as reaction time or temperature, and generally in the range of from 500 g/mol to 30 000 g/mol. Preferably, it is between 1000 g/mol and 15 000 g/mol, more preferably between 1500 g/mol and 10 000 g/mol. The hydroxyl group content of the copolymer (P) in a 100% form is preferably from 1% by weight to 5% by weight, preferably from 1.5% by weight to 4.5% by weight, particularly preferably from 1.75% by weight to 3.5% by weight.

The acid group present before, during or after the copolymer (P) is dispersed in water It is converted to its salt form at least proportionally by the addition of a suitable neutralizing agent. Suitable neutralizing agents are organic amines or water-soluble inorganic bases such as soluble organic hydroxides, metal carbonates or metal hydrogencarbonates such as sodium hydroxide or potassium hydroxide.

Examples of suitable amines are butyldiethanolamine, N-ethylmorpholine, triethylamine, ethyldiisopropylamine, N,N-dimethylethanolamine, N,N-dimethylisopropanolamine, N- Methyldiethanolamine, diethylethanolamine, triethanolamine, butanolamine, morpholine, 2-aminomethyl-2-methylpropanol or isophoronediamine. Ammonia may also be used in proportion to the mixture. Particularly preferred are triethanolamine, N,N-dimethylethanolamine and ethyldiisopropylamine.

The theoretical degree of neutralizing agent addition amount [acid group] is 40% to 150%, preferably 60% to 120%. The degree of neutralization here is the ratio of the acid functionality of the base pair copolymer to which the neutralizing component is added. The aqueous copolymer dispersion of the present invention generally has a pH of from 6 to 10, preferably from 6.5 to 9.

The invention will be further described with reference to a number of specific examples and other aspects. They may be freely combined unless the context clearly indicates otherwise. If a plurality of monomers of the same name (for example, (M1)) are used in a specific example, this does not mean that the monomers need to be the same. Moreover, the use of plural numbers with respect to monomers when describing the present invention does not imply that more than one type of monomer under the name present is required.

In a specific example of the dispersion according to the invention, the solids content of the dispersion ranges from 10% by weight to 90% by weight (preferably from 40% by weight to 60% by weight) based on the total weight of the dispersion, and The organic solvent is present in an amount of 5% by weight (preferably 4% by weight, more preferably 2% by weight) based on the total weight of the dispersion. The solids content is determined as stated in DIN-EN ISO 3251. The organic solvent to be reduced or avoided comprises acetone and other solvents having a boiling point below 100 °C.

In a further embodiment of the dispersion according to the invention, the carboxylic acid in the glycidyl ester of the aliphatic carboxylic acid comprises 8, 9, and/or 10 carbon atoms. Preferred is a glycidyl ester of neodecanoic acid.

In a further embodiment of the dispersion according to the invention, (M1) is isodecyl (meth)acrylate (M2) with the formula H ₂ C=CH-OC(=O)-C(R1)(R2) ( CH ₃ ) represents, wherein R 1 and R 2 represent a saturated alkyl group (M 3 ) having a total of 6, 7 or 8 carbon atoms of hydroxyethyl (meth)acrylate and/or hydroxypropyl (meth)acrylate (M 4 ) (Meth)acrylic acid (M5) is styrene, methyl (meth)acrylate and/or n-butyl (meth)acrylate.

In a further embodiment of the dispersion according to the invention, the monomers (M1) to (M5) are used in the following amounts: (M1) ≧ 0.1% by weight to ≦ 3% by weight (preferably ≧ 0.5% by weight to ≦ 1.5% by weight) %) (M2) from 0.1% by weight to about 3% by weight (preferably from about 0.5% by weight to about 1.5% by weight) (M3) from 10% by weight to about 30% by weight (preferably from 15% by weight to ≦25% by weight) %) (M4) from 1% by weight to about 10% by weight (preferably from 3% by weight to 8% by weight) (M5) from 40% by weight to ≦80% by weight (preferably from 50% by weight to ≦65% by weight) %) and the epoxy propyl ester of the aliphatic carboxylic acid is used in an amount of from 5% by weight to 20% by weight (preferably from 7% by weight to 15% by weight) based on the total weight of the solids in the dispersion. The total amount is up to 100% by weight. In a further embodiment of the dispersion according to the invention, the copolymer (P) is synthesized by first synthesizing a copolymer (P1) from a mixture of radically polymerisable monomers (M), the monomer (M) comprising: (M1) Vinyl ester (M3) hydroxy functional (M3) hydroxy-functional, radically polymerizable monomer (M5) having a C1 to C12 hydrocarbon group in the alcohol moiety of the cycloaliphatic ester (M2) aliphatic carboxylic acid of acrylic acid and/or methacrylic acid a hydroxyl-free-without carboxyl-(meth)acrylate and/or vinyl aromatic, followed by addition of a mixture of free-radically polymerizable monomers (M) to the copolymer (P1) in one or more subsequent steps, The monomer (M) includes: (M3) hydroxy-functional, free-radically polymerizable monomer (M4) carboxyl functional, radical-polymerizable monomer (M5) having a C1 to C12 hydrocarbon group in the alcohol moiety, hydroxy-free and carboxy-free (meth)acrylic acid Ester and/or vinyl aromatic and include a glycidyl ester of an aliphatic carboxylic acid.

In a further embodiment of the dispersion according to the invention: - for the synthesis of the copolymer (P1): (M1) is isodecyl (meth)acrylate (M2) with the formula H ₂ C=CH-OC (=O ) -C (R1) (R2) (CH 3) , where R1 and R2 represents a saturated alkyl group having a total of 6, 7 or 8 carbon atoms (M3) is a (meth) acrylate, hydroxyethyl methacrylate and / or ( Hydroxypropyl methacrylate (M5) is styrene, methyl (meth)acrylate and/or n-butyl (meth)acrylate - for one or more subsequent steps: (M3) is (meth)acrylic acid The hydroxyethyl ester and/or hydroxypropyl (meth)acrylate (M4) is (meth)acrylic acid (M5) which is styrene, methyl (meth)acrylate and/or n-butyl (meth)acrylate.

Vinyl monomer H ₂ C=CH-OC(=O)-C(R1)(R2)(CH ₃ ) (wherein R 1 and R 2 represent a saturated alkyl group having a total of 6, 7 or 8 carbon atoms) Available as VeoVa® Monomer 9, 10 and 11 (Hexion Specialty Chemicals BV, Rotterdam, NL) with VeoVa® Monomer 9 as the best. In terms of the glass transition temperature of its homopolymer, the stated monomers are different: VeoVa® 9 (+70 ° C), VeoVa® 10 (-3 ° C), VeoVa® 11 (-40 ° C).

Preferred monomers (M1) to (M5) are used herein in the following amounts: - for synthetic copolymer (P1): (M1) ≧ 10% by weight to ≦ 30% by weight (preferably ≧ 15% by weight to ≦25) weight%) (M2) from 5 wt% to 25 wt% (preferably from 10 wt% to 20 wt%) (M3) from 10 wt% to 30 wt% (preferably from 15 wt% to 25 wt%) (M5) ≧ 30% by weight to ≦60% by weight (preferably ≧40% by weight to ≦50% by weight) based on the total weight of solids in (P1), a given amount of up to 100% by weight - for one or more Subsequent steps: (M3) ≧ 10% by weight to ≦30% by weight (preferably ≧15% by weight to ≦25% by weight) (M4) ≧1% by weight to ≦10% by weight (preferably ≧3% by weight to ≦ 8% by weight) (M5) ≧ 40% by weight to ≦80% by weight (preferably ≧50% by weight to ≦65% by weight) and the epoxy propyl ester of the aliphatic carboxylic acid is present in an amount of from 5% by weight to ≦20 by weight % (preferably ≧ 7 wt% to ≦ 15 wt%), based on the total weight of solids in the dispersion, a total amount of up to 100% by weight.

The invention also relates to a process for the manufacture of a dispersion according to the invention comprising the step of free-radical polymerization of a mixture of monomers (M) comprising: (M1) cycloaliphatic acid of acrylic acid and/or methacrylic acid The vinyl ester (M3) hydroxy functional group of the ester (M2) aliphatic carboxylic acid, the carboxyl functional group of the radically polymerizable monomer (M4), and the radically polymerizable monomer (M5) have a C1 to C12 hydrocarbon group in the alcohol moiety. Hydroxyl-free and non-carboxy-(meth) acrylate and/or vinyl aromatic to obtain copolymer (P), wherein the mixture further comprises a glycidyl ester of an aliphatic carboxylic acid.

The solids content of the dispersion is preferably in the range of from 10% by weight to 90% by weight based on the total weight of the dispersion, wherein the organic solvent is present in an amount of 5% by weight, based on the total weight of the dispersion.

In a further embodiment of the process according to the invention, the synthesis of the copolymer (P) The copolymer (P1) is synthesized by first mixing a mixture of radically polymerizable monomers (M) comprising: (M1) a cycloaliphatic ester (M2) ester of acrylic acid and/or methacrylic acid. a vinyl ester of a carboxylic acid (M3), a hydroxyl-functional, radically polymerizable monomer (M5) having a C1 to C12 hydrocarbon group in the alcohol moiety, a hydroxyl-free and a carboxyl-free (meth) acrylate and/or a vinyl group Aromatic, followed by addition of a mixture of free-radically polymerizable monomers (M) to the copolymer (P1) in one or more subsequent steps, the monomer (M) comprising: (M3) hydroxy-functional, free-radical polymerization The (M4) carboxyl functional, radically polymerizable monomer (M5) having a C1 to C12 hydrocarbon group in the alcohol moiety without hydroxyl group-and carboxyl group-free (meth) acrylate and/or vinyl aromatic and including a fat a glycidyl ester of a carboxylic acid.

In a further embodiment of the process according to the invention, the monomers (M1) to (M5) are used in the following amounts: - for the synthetic copolymer (P1): (M1) ≧ 10% by weight to ≦ 30% by weight (preferably ≧15% by weight to ≦25% by weight) (M2) ≧ 5% by weight to ≦ 25% by weight (preferably ≧ 10% by weight to ≦ 20% by weight) (M3) ≧ 10% by weight to ≦ 30% by weight (preferably ≧15% by weight to ≦25% by weight) (M5) ≧ 30% by weight to ≦60% by weight (preferably ≧40% by weight to ≦50% by weight) based on the total weight of solids in (P1), given a total amount Up to 100% by weight - for one or more subsequent steps: (M3) ≧ 10% by weight to ≦ 30% by weight (preferably ≧ 15% by weight to ≦ 25% by weight) (M4) ≧ 1% by weight to ≦ 10% by weight % (preferably ≧3 wt% to ≦8 wt%) (M5) from 40% by weight to 80% by weight (preferably from 50% by weight to ≦65% by weight) and the epoxy propyl ester of the aliphatic carboxylic acid is from 5% by weight to ≦20% by weight (preferably ≧ 7 wt% to ≦ 15 wt%), based on the total weight of the solids in the dispersion, a total amount of up to 100% by weight.

A further aspect of the invention uses the dispersion according to the invention as a coating material.

The invention further relates to the use of a dispersion according to the invention as a binder for an aqueous two-component polyurethane coating in combination with a crosslinking agent (X). The crosslinking agent (X) used is preferably a polyisocyanate. Such polyisocyanates have two or more NCO groups per molecule and are based, for example, on isophorone diisocyanate, hexamethylene diisocyanate, 1,4-diisocyanatocyclohexane, bis(4-isocyanato) Cyclohexane)methane, 1,3-diisocyanatobenzene, triisocyanatodecane or isomeric 2,4- and 2,6-TDI, and may further contain urethane, trimer Isocyanate and/or biuret groups. The polyisocyanate may also be blocked as appropriate.

Particularly preferred is the use of low viscosity polyisocyanates of the above type based on aliphatic or cycloaliphatic isocyanates. These may also be hydrophilized as appropriate.

The polyisocyanate used as a crosslinking agent generally has a viscosity of 10 to 5000 mPas at 23 ° C, and may be blended with a small amount of an inert solvent if necessary in order to adjust the viscosity.

The copolymers of the present invention are generally sufficiently hydrophilic to disperse the hydrophobic crosslinker resin even without additional emulsifiers. However, this does not exclude the use of a foreign emulsifier.

Water soluble or dispersible polyisocyanates can be obtained, for example, by modifying carboxylic acid esters, sulfonate and/or polyethylene oxide groups and/or polyethylene oxide/polyoxypropylene groups. The polyisocyanate can be rendered hydrophilic by, for example, reacting with a substoichiometric monohydric hydrophilic polyether alcohol. The preparation of such a hydrophilized polyisocyanate is described, for example, in EP-A 0 540 985 (p. 3, 1.55 to p. 4, 1.5). Also highly suitable are the polyisocyanates containing urea groups as described in EP-A 959 087 (p. 3, 1.39 to 51), which are low monomer content under allophanatization conditions. The polyisocyanate is prepared by reacting with a polyethylene oxide polyether alcohol. Also suitable for use in water based on triisocyanate decane as described in DE-A 100 078 21 (p. 2, 1.66 to p. 31.5) Disperse the isocyanate mixture. Particularly suitable and preferred are polyisocyanates which are hydrophilized with ionic groups, in particular sulfonate groups, for example of the type described in DE-A 100 24 624 (p. 3 11.13 to 33).

It is of course also possible in principle to use mixtures of different crosslinker resins.

The ratio of the hydroxyl group of the binder component to the isocyanate group of the crosslinking agent (X) is typically from 3:1 to 1:5, preferably from 2:1 to 1:3, particularly preferably from 1:1 to 1:2.

A further aspect of the invention is an aqueous two-component polyurethane coating material comprising a dispersion according to the invention and an isocyanate group-containing crosslinking agent (X).

Preferred crosslinkers (X) include oligomers or reactions of 1,6-hexamethylene diisocyanate and/or diphenylmethane diisocyanate and/or hexamethylene diisocyanate and/or diphenylmethane. product.

The coating material comprising the aqueous secondary dispersion of the present invention can be applied to any desired substrate, such as wood, metal, plastic, paper, leather, fabric, felt, glass or mineral substrates, and also coated substrates. . A particularly preferred application is the use of aqueous coating materials for the manufacture of coatings for absorbent substrates such as wood or open-hole mineral substrates. A preferred substrate is wood.

The invention also provides wood articles coated with a coating material comprising an aqueous secondary dispersion of the invention.

The coating material may be used as such or in combination with further adjuvants and adjuvants known in the coating art, such as fillers and pigments.

The coating material comprising the secondary dispersion of the invention can be applied in a known manner, for example by spreading, pouring, knife coating, injection, spraying, spin coating, rolling or dipping.

The invention will be described by the following examples without wishing to be limited thereto.

Word exchange:

The nature of the determination is solids content (thick film method: capped, 1 g sample, 1 h at 125 ° C, convection oven, shown in DIN EN ISO 3251); acid value (mg KOH / g sample, with 0.1 mol / l NaOH solution Titration, as stated in DIN 53402); OH value (mg KOH/g sample, acetylated, hydrolyzed, titrated with 0.1 mol/l NaOH, as indicated in DIN 53240).

MEK wiping test

The cotton dough soaked with methyl ethyl ketone (MEK) was moved back and forth 100 times on a coating film at a constant pressure (100 double rubs). If severe damage or delamination is observed even after less than 100 double rubs, the test is interrupted. After the test, the sheet was visually evaluated for turbidity and/or film delamination.

The pendulum hardness is determined in accordance with DIN 53157.

The Buchholz hardness is determined according to DIN 53153.

The Erichsen test was carried out in accordance with DIN 53156.

The pencil hardness is determined according to DIN EN ISO 13523-4.

Example 1: Precursor

Polyacrylate precursors were prepared using the following ingredients:

Part 1 was loaded into a 10 L reactor equipped with a stirrer, reflux condenser, temperature measurement and monomer feed (dropper funnel) and covered with a gentle nitrogen stream for 1 hour. The batch was then heated with stirring to 148 °C. After the temperature has been reached, part 2 is added during 20 minutes. Immediately thereafter, portions 3 and 4 were metered in parallel during 4.5 hours, optionally cooled so that the temperature did not exceed 153 °C. After the addition was completed, the batch was kept at 148 ° C for 1 hour. Cooling produces a high viscosity resin with a solids content of 68.5 ± 1% by weight.

Example 2: Copolymer dispersion

The polyacrylate copolymer dispersion was prepared using the following ingredients:

Part 1 was loaded into a 30 L reactor equipped with a stirrer, reflux condenser, temperature measurement and monomer feed (dropper funnel) and covered with a gentle nitrogen stream for 1 hour. The batch was then heated with stirring to 148 °C. After the temperature has been reached, part 2 is added during 20 minutes. Immediately thereafter, portions 3 and 4 were metered in parallel during 4.5 hours, optionally cooled. After the addition was completed, the batch was held at 148 ° C for 0.5 hours. Parts 5 and 6 were then metered in during 1.5 hours. The batch was then held at 148 ° C for one hour and then cooled to 120 ° C. Reduce the pressure to less than 2.5 bar and take 5000 g of sample. After cooling to 95 ° C, Part 7 was added and the mixture was stirred for 30 minutes. Finally, Part 8 was added for dispersion during 30 minutes, followed by stirring at 80 ° C for 2 hours and passing through a filter.

Example 3: Copolymer dispersion

The polyacrylate copolymer dispersion was prepared using the following ingredients:

Part 1 was loaded into a 30 L reactor equipped with a stirrer, reflux condenser, temperature measurement and monomer feed (dropper funnel) and covered with a gentle nitrogen stream for 1 hour. The batch was then heated with stirring to 148 °C. After the temperature has been reached, part 2 is added during 20 minutes. Immediately thereafter, portions 3 and 4 were metered in parallel during 4.5 hours, optionally cooled. After the addition was completed, the batch was held at 148 ° C for 0.5 hours. Parts 5 and 6 were then metered in during 1.5 hours. The batch was then held at 148 ° C for one hour and then cooled to 120 ° C. Reduce the pressure to less than 2.5 bar and take 5000 g of sample. After cooling to 95 ° C, Part 7 was added and the mixture was stirred for 30 minutes. Finally, Part 8 was added for dispersion during 30 minutes, followed by stirring at 80 ° C for 2 hours and passing through a filter.

Example 4: Coating test

The coating formulation is prepared using the following ingredients in a given amount by weight:

The test results of the coatings are summarized in the table below. RT = dried at room temperature, 30 '60 ° C = stored at 60 ° C for 30 minutes.

Claims (15)

An aqueous secondary copolymer dispersion comprising a copolymer (P) synthesized from a mixture of radical polymerizable monomers (M) comprising: (M1) acrylic acid and/or methacrylic acid Cycloaliphatic ester (M2) aliphatic carboxylic acid vinyl ester (M3) hydroxy functional, radically polymerizable monomer (M4) carboxyl functional, radically polymerizable monomer (M5) having a C1 to C12 hydrocarbon group in the alcohol moiety The hydroxy-free and carboxyl-free (meth) acrylate and/or vinyl aromatic groups are characterized in that the mixture further comprises a glycidyl ester of an aliphatic carboxylic acid. The dispersion according to claim 1, wherein the solid content in the dispersion ranges from 10% by weight to 90% by weight based on the total weight of the dispersion, and wherein the organic solvent is in an amount of 5% by weight Exist, based on the total weight of the dispersion. The dispersion according to claim 1, wherein the carboxylic acid comprises 8, 9, and/or 10 carbon atoms in the glycidyl ester of the aliphatic carboxylic acid. According to the dispersion of claim 1, wherein: (M1) is isodecyl (meth)acrylate (M2) is a formula of H ₂ C=CH-OC(=O)-C(R1)(R2) (CH ₃ ) represents wherein R 1 and R 2 represent a saturated alkyl group (M 3 ) having a total of 6, 7 or 8 carbon atoms of hydroxyethyl (meth)acrylate and/or hydroxypropyl (meth)acrylate (M 4 ) (M)acrylic acid (M5) is styrene, methyl (meth)acrylate and/or n-butyl (meth)acrylate. The dispersion according to claim 1, wherein the monomers (M1) to (M5) are used in the following amounts: (M1) ≧ 0.1% by weight to ≦ 3 by weight (M2) ≧ 0.1% by weight to ≦ 3 by weight (M3) from 10% by weight to ≦30 weight (M4) from 1% by weight to 10% by weight (M5) ≧ 40% by weight to ≦80% by weight and the epoxy propyl ester of the aliphatic carboxylic acid is present in an amount of from 5% by weight to 20% by weight, based on the dispersion Based on the total weight of the solids, the given amount is up to 100% by weight. The dispersion according to claim 1, wherein the copolymer (P) is synthesized by first synthesizing a copolymer (P1) from a mixture of radically polymerizable monomers (M), the monomer (M) comprising : (M1) Vinyl ester (M3) of a cycloaliphatic acid (M2) aliphatic carboxylic acid of acrylic acid and/or methacrylic acid. The hydroxy functional, radically polymerizable monomer (M5) has a C1 to C12 hydrocarbon group in the alcohol moiety. a hydroxy-free group with no carboxyl-(meth) acrylate and/or vinyl aromatic, followed by addition of a mixture of free-radically polymerizable monomers (M) to the copolymer (P1) in one or more subsequent steps The monomer (M) comprises: (M3) a hydroxyl functional group, a radical polymerizable monomer (M4) carboxyl function, and a radical polymerizable monomer (M5) having a hydroxyl group of a C1 to C12 hydrocarbon group in the alcohol moiety - It is a non-carboxy-(meth) acrylate and/or vinyl aromatic and includes a glycidyl ester of an aliphatic carboxylic acid. A dispersion according to claim 6 wherein: - for the synthesis of the copolymer (P1): (M1) is isodecyl (meth)acrylate (M2) with the formula H ₂ C=CH-OC ( =O)-C(R1)(R2)(CH ₃ ) represents wherein R1 and R2 represent a saturated alkyl group (M3) having a total of 6, 7 or 8 carbon atoms which is hydroxyethyl (meth)acrylate and/or Or hydroxypropyl (meth)acrylate (M5) is styrene, methyl (meth)acrylate and/or n-butyl (meth)acrylate - for one or more subsequent steps: (M3) is (A) Hydroxyethyl acrylate and/or hydroxypropyl (meth)acrylate (M4) is (meth)acrylic acid (M5) as styrene, methyl (meth)acrylate and/or n-butyl (meth)acrylate ester. The dispersion according to claim 6 wherein the monomers (M1) to (M5) are used in the following amounts: - for the synthesis of the copolymer (P1): (M1) ≧ 10% by weight to ≦ 30 by weight (M2) ≧ 5 wt% to ≦ 25 wt% (M3) ≧ 10 wt% to ≦ 30 wt% (M5) ≧ 30 wt% to ≦ 60 wt% based on the total weight of the solid in (P1), the given amount A total of up to 100% by weight - for the one or more subsequent steps: (M3) ≧ 10% by weight to ≦ 30% by weight (M4) ≧ 1% by weight to ≦ 10% by weight (M5) ≧ 40% by weight to ≦80 The wt% and the epoxy propyl ester of the aliphatic carboxylic acid are present in an amount of from 5% by weight to 20% by weight, based on the total weight of the solids in the dispersion, which amounts to 100% by weight. A method of producing a dispersion according to one or more of items 1 to 8 of the patent application, comprising the step of radically polymerizing a mixture of monomers (M) comprising: (M1) acrylic acid and/or Vinyl ester of methacrylic acid (M2) aliphatic carboxylic acid (M3) hydroxy functional, radically polymerizable monomer (M4) carboxyl functional, radically polymerizable monomer (M5) having in the alcohol moiety a hydroxyl group-free and/or carboxyl-free (meth) acrylate and/or vinyl aromatic group of a C1 to C12 hydrocarbon group to obtain a copolymer (P), characterized in that the mixture further comprises a glycidyl ester of an aliphatic carboxylic acid . The method of claim 9, wherein the copolymer (P) is synthesized by first synthesizing a copolymer (P1) from a mixture of radically polymerizable monomers (M), the monomer (M) comprising: (M1) Vinyl ester (M3) hydroxy functional (M3) hydroxy-functional, radically polymerizable monomer (M5) having a C1 to C12 hydrocarbon group in the alcohol moiety of the cycloaliphatic ester (M2) aliphatic carboxylic acid of acrylic acid and/or methacrylic acid a hydroxyl-free-without carboxyl-(meth)acrylate and/or vinyl aromatic, followed by addition of a mixture of free-radically polymerizable monomers (M) to the copolymer (P1) in one or more subsequent steps, The monomer (M) comprises: (M3) a hydroxyl functional group, a radical polymerizable monomer (M4) carboxyl function, and a radically polymerizable monomer (M5) having a hydroxyl group of a C1 to C12 hydrocarbon group in the alcohol moiety - Carboxyl-(meth)acrylate and/or vinyl aromatic and includes a glycidyl ester of an aliphatic carboxylic acid. The method according to claim 9 wherein the monomers (M1) to (M5) are used in the following amounts: - synthesis of the copolymer (P1): (M1) ≧ 10% by weight to ≦ 30% by weight (M2) ≧ 5 wt% to ≦25 wt% (M3) ≧ 10 wt% to ≦ 30 wt% (M5) ≧ 30 wt% to ≦ 60 wt% based on the total weight of the solid in (P1), the give Quantitative total up to 100% by weight - for the one or more subsequent steps: (M3) ≧ 10% by weight to ≦ 30% by weight (M4) ≧ 1% by weight to ≦ 10% by weight (M5) ≧ 40% by weight to ≦ 80% by weight and the epoxy propyl ester of the aliphatic carboxylic acid is present in an amount of from 5% by weight to 20% by weight, based on the total weight of the solids in the dispersion, the total amount being up to 100% by weight. A use of a dispersion according to one or more of claims 1 to 8 of the patent application as a coating material. A use of a dispersion according to one or more of claims 1 to 8 as a binder for an aqueous two-component polyurethane coating and in combination with a crosslinking agent (X). An aqueous two-component polyurethane coating material comprising a dispersion according to one or more of items 1 to 8 of the patent application and an isocyanate group-containing crosslinking agent (X). The coating material according to claim 14, wherein the crosslinking agent (X) comprises 1,6-hexamethylene diisocyanate and/or diphenylmethane diisocyanate and/or hexamethylene diisocyanate and/or Or an oligomer or reaction product of diphenylmethane.