WO2003068869A2 - Coatings for carrier materials for making an oxygen barrier - Google Patents

Abstract

The invention relates to a method for the production of packaging materials with oxygen-blocking properties, wherein a carrier material is coated and then hardened with a coating agent (I) containing: (A1) at least one polymerizable compound with one or more copolymerizable, ethylenically unsaturated groups; (A2) optionally at least one additional polymerizable compound with one or more copolymerizable, ethylenically unsaturated groups; (B) optionally a copolymerizable, ethylenically unsaturated group containing a reactive thinner; (C) optionally a photoinitiator and (D) optionally other additives.

Description

Coatings for carrier materials to achieve an oxygen barrier

description

The present invention relates to flat coatings of films, papers, cardboards or cartons for the production of barrier coatings.

In the packaging industry, packaging materials based on foils, paper, cardboard or cardboard are often equipped with a coating to increase the oxygen, fat and aroma density of the packaging material. Equipping the packaging material in this way is also referred to as a barrier coating. Packaging materials that are equipped with a barrier coating are used in a variety of ways, for example for packaging foods such as ready meals, dairy products, nuts, vegetables or fruit. The aroma density (aroma barrier) of the packaging material is also an important quality criterion for the packaging of food and flavored consumer goods, such as washing powder.

To date, polyvinylidene chloride (PVDC) or copolymers of vinylidene dichloride have been used to produce such barrier coatings. Such materials are, however, in view of their environmental compatibility, especially in their disposal, e.g. through combustion, problematic. There has been no shortage of attempts. To replace polyvinylidene chloride and its copolymers with chlorine-free polymers.

For example, polyvinyl acetate, polyethylene-polyvinyl alcohol copolymers and comparable substances for the production of barrier coatings have been described. However, the barrier coatings obtainable in this case have only inadequate application properties. In particular, because of their hydrophilicity, these products show a high solubility in water. The aforementioned products are therefore not acceptable for use in packaging food.

EP-A 700 731 describes a process for the production of packaging materials with oxygen barriers, in which a packaging substrate is coated with a dispersion comprising a copolymer of ethylenically unsaturated carboxylic acids, dicarboxylic acids, their half-esters or anhydrides and optionally other monomers and polyester. A disadvantage of these systems is that they are relatively sensitive to moisture.

This is evident from the fact that these coatings or those based on polyvinyl alcohol become sticky on contact with moisture or even detach from the carrier material.

The object of the present invention was to develop coated carrier materials which are moisture-stable and have low oxygen permeability.

The object was achieved by a process for the production of packaging materials with oxygen barrier properties, in which a carrier material containing a coating agent (I)

(AI) at least one polymerizable compound having one or more copolymerizable, ethylenically unsaturated groups,

(A2) optionally at least one further polymerizable compound having one or more copolymerizable, ethylenically unsaturated groups,

(B) optionally a copolymerizable reactive thinner containing ethylenically unsaturated group,

(C) optionally a copolymerizable photoinitiator containing ethylenically unsaturated group and

(D) optionally further additives,

coated and then hardened.

The carrier materials obtainable in this way generally have an oxygen permeability of not more than 100 cm ³ / (m ² xdx bar), based on a layer thickness of 100 μm. Below this value, this document speaks of an oxygen barrier property.

Suitable substrates for packaging such as e.g. Films, for example made of metal or plastic, which can also be foamed, paper, cardboard or cardboard are used.

Suitable films can, for example, consist of or contain polyolefins, for example (co) polymers of ethylene, propylene, 1-butene, 2-butene, isobutene or styrene, or of polyalkylene terephthalates, for example made of polyethylene terephthalate, polypropylene terephthalate or polybutylene terephthalate.

Examples of polyethylenes are those which are produced by the high-pressure or low-pressure process (high-pressure or low-pressure polyethylene).

These can be branched polyethylenes with low density (approx. 0.915-0.935 g / cm ³ ) and degrees of crystallinity of approx. 10 40-50% (LDPE types), or products with higher molar mass (HMW-LDPE, abbreviation after DIN 7728, Part 1, Jan. 1988).

By copolymerizing ethylene with longer-chain olefins, especially with butene and octene, products with a reduced degree of branching can be obtained (LLD-PE).

Polyethylenes from the low pressure process are largely linear and unbranched (HDPE), have degrees of crystallinity of 60-80% and a density of approx. 0.94-0.965 g / cm ³ and molar masses of approx. 20 200000-5000000 g / mol resp . 3000000-6000000 g / mol (HD-HMW-PE or UHMW-HD-PE).

Medium density (MDPE) products made from blends of low and high density polyethylenes are also commercially available.

Linear polyethylenes with densities <0.918 g / cm ³ (VLD-PE) are also conceivable.

30 examples of polypropylenes are those with an average relative molar mass of approx. 150000-600000 g / mol or also copolymers of propylene with ethylene (EPM, EPDM).

The spatial orientation of the chains in polypropylene films can be achieved by uni- or bisaxial stretching (OPP films). Stretched polypropylene films are preferred.

Examples of polybutenes are those with molar masses of 700000-3000000 g / mol, especially those with melting points of 40 125-130 ° C and a density of 0.91-0.92 g / cm ³ .

PVC films are also conceivable, the polyvinyl chloride generally having a molar mass of 30,000 to 130,000 g / mol. Soft PVC is preferred, which has a content of 45 plasticizers of generally more than 12% by weight.

Polystyrene can be used with a molecular weight of 170,000 to 1000000 g / mol and a density of approx. 1.05 g / cm ³ .

According to DIN 6730 of August 1985, paper is understood to be a flat material consisting essentially of fibers of predominantly vegetable origin, which is formed by dewatering a fibrous substance suspension on a sieve, producing a fiber felt which is then compressed and dried.

Paper with a basis weight of up to 225 g / m ² can be used, with a basis weight of more than 225 g / m ² one speaks of cardboard.

Cardboard generally has a basis weight of 150-600 g / m ² and is usually stiffer than paper of the same basis weight.

If a film made of polyolefin or polyalkylene terephthalate is used as the carrier material, the coated film system, ie carrier material and coating, generally also has a low water vapor permeability in addition to the low oxygen permeability desired according to the invention, generally below 25 g / ( m ² X d), based on 100 μm layer thickness, at 39 ° C. and 90% relative humidity, preferably below 20, particularly preferably below 15, very particularly preferably below 10 and in particular below 5 g / (m ² X d).

If paper, cardboard or cardboard is used as the carrier material, the film system has, in addition to the low oxygen permeability, a relatively high water vapor permeability of generally more than 100 g / (m ² xd), based on 100 m layer thickness, at 39 ° C. and 90% relative humidity, preferably more than 250 and particularly preferably more than 500 g / (m ² xd).

If a low water vapor permeability is also desired as the carrier material for paper, cardboard or cardboard, the carrier material or film system can also be provided with a so-called XSB coating.

These can be, for example, styrene and butadiene and, if appropriate, further monomers in copolymerized form and, if appropriate, coatings containing other constituents, such as, for example, those as claimed in DE-Al 27 41 824 or those as described in EP-AI 393 451, there in particular from column 2, line 16 to column 8, line 53. Preferred coatings are those which contain hydrogenated styrene-butadiene copolymers, as described in DE-Al 101 03 065. According to the invention, the carrier material is coated with a coating composition (I) described below in a manner known per se.

One subject of this application is the use of radiation-curable coating compositions as an oxygen barrier.

The coating compositions (I) which can be used according to the invention to achieve an oxygen barrier generally have an increased hydrophilicity. The individual components are known per se. They usually contain at least one radical polymerizable group.

Preferred coating compositions (I) are those in which (AI) and (A2) and (B) are capable of dissolving at least 2% by weight of distilled water homogeneously together at 25 ° C., particularly preferably at least 5% by weight, very particularly preferably at least 10, in particular at least 15% by weight and exceptionally preferably at least 20% by weight.

Polymerizable groups can be those which have unsaturated bonds, preferably carbon-carbon double bonds.

Radically polymerizable groups are, for example, isolated ethylenically unsaturated groups, conjugated unsaturated groups, vinylaromatic groups, vinyl and vinylidene chloride groups, N-vinylamides, vinylpyrrolidones, vinyl lactams, vinyl esters, (meth) acrylic esters or acrylonitriles.

Acrylic and methacrylic groups are preferred, particularly preferably acrylic groups.

The coating compositions which can be used according to the invention are preferably radiation-curable.

Usually, a radiation-curable coating composition (I) which can be used according to the invention contains

(AI) at least one polymerizable compound with one or more copolymerizable, ethylenically unsaturated groups,

(A2) optionally at least one further polymerizable compound having one or more copolymerizable, ethylenically unsaturated groups, (B) optionally monofunctional reactive diluent,

(C) optionally photoinitiator and

(D) optionally further additives.

Compounds (AI) which are free-radically polymerizable are compounds having one or more, i.e. at least two, copolymerizable, ethylenically unsaturated groups.

Examples of a compound (AI) with a copolymerizable, ethylenically unsaturated group are acrylic acid, methacrylic acid, (meth) acrylonitrile, (meth) acrylamide, maleic acid, fumaric acid, 3-acryloylpropionic acid, hydroxyethyl (meth) acrylate, diethylene glycol monoacrylate, triethylene glycol monoacrylate, Oligoethylene glycol monoacrylate, ethylene glycol monomethyl ether acrylate, diethylene glycol monomethyl ether acrylate, dimethylaminoethyl (meth) acrylate, phenol glycidyl ether acrylate, acrylates of glycidyl ethers of monoalcohols, such as, for example Methanol, ethanol, n-propanol, iso-propanol, n-butanol or 1-hexanol, N-vinyl pyrrolidone and N-vinyl caprolactam. These are particularly preferred when no reactive diluent (B) is used. Acrylic acid is particularly preferred.

Compounds (AI) are preferably (meth) acrylate compounds, particularly preferred are the acrylate compounds, i.e. the derivatives of acrylic acid.

Preferred (meth) acrylate compounds (AI) contain, for example, at least 2, preferably 2 to 10 and particularly preferably

2 to 5, very particularly preferably 2 to 4 and in particular 2 to

3 copolymerizable, ethylenically unsaturated double bonds.

Unless stated otherwise, the number-average molecular weight M _{n of} the compounds (AI) is preferably less than 10,000, particularly preferably less than 5000, very particularly preferably less than 3000 g / mol and more than 180 g / mol (determined by gel chromatography with polystyrene as Standard and tetrahydrofuran as eluent).

The method for determining polydispersity and the number-average and weight-average molecular weights M _n and M _w is described in the analyst's pocket book, vol. 4, pages 433 to 442, Berlin 1984.

Preferred (meth) acrylate compounds (AI) may be mentioned (Meth) acrylic acid esters and in particular acrylic acid esters of highly functional alcohols, in particular those which, besides the hydroxyl groups, contain no further functional groups or at most ether groups. Examples of such multifunctional alcohols are, for example, bifunctional alcohols, such as ethylene glycol, propylene glycol and their more highly condensed homologs, for example such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol etc., 1,2-, 1,3- or 1,4-butanediol, 1 , 5-pentanediol, 1, 6-hexanediol, 3-methyl-l, 5-pentanediol, neopentyl glycol, alkoxylated phenolic compounds such as ethoxylated or propoxylated bisphenols, 1,2-, 1,3- or 1,4-cyclohexanedi- methanol, trifunctional and higher functional alcohols, such as glycerol, trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol and the correspondingly alkoxylated, in particular ethoxylated and / or propoxylated alcohols obtainable from these by alkoxylation.

The alkoxylation products are preferred in a known manner by reacting the above alcohols with alkylene oxides

Ethylene and / or propylene oxide, particularly preferably ethylene oxide. For example, the degree of alkoxylation per hydroxyl group is 0 to 20, preferably 0 to 10 and preferably 0 to 5, i.e. 1 mol of hydroxyl groups can be alkoxylated with up to 20 mol of alkylene oxides.

Also preferred (meth) acrylate compounds (AI) are those compounds which can be obtained by reacting (meth) acrylic acid with the glycidyl ethers of the above-mentioned polyfunctional alcohols.

These epoxy (meth) acrylates can be obtained by reacting epoxides with (meth) acrylic acid. Examples of suitable epoxides are epoxidized olefins, aromatic glycidyl ethers or aliphatic glycidyl ethers, preferably those of aromatic or aliphatic glycidyl ethers.

Epoxidized olefins can be, for example, ethylene oxide, propylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, vinyl oxirane, styrene oxide or epichlorohydrin, preference is given to ethylene oxide, propylene oxide, isobutylene oxide, vinyl oxirane, styrene oxide or epichlorohydrin, particularly preferably ethylene oxide, propylene oxide or epichlorohydrin and very particularly preferably ethylene oxide and epichlorohydrin.

Aromatic glycidyl ethers are e.g. B. Bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol B diglycidyl ether, bisphe nol-S-diglycidyl ether, hydroquinone diglycidyl ether, alkylation products of phenol / dicyclopentadiene, for example 2, 5-bis [(2, 3-epoxypropoxy) phenyl] octahydro-4, 7-methano-5H-indene) (CAS no ,

[13446-85-0]), tris [4- (2, 3-epoxypropoxy) phenyljmethane isomers (CAS No. [66072-39-7]), phenol-based epoxy novolaks (CAS No.

[9003-35-4]) and cresol based epoxy novolaks (CAS no.

[37382-79-9]).

Aliphatic glycidyl ethers are, for example, ° 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1, 1, 2, 2-tetrahedron [4- (2,3-epoxypropoxy) phenyl] CAS No. [27043-37-4]), diglycidyl ether of polypropylene glycol (α, ω-bis (2, 3-epoxypropoxy) poly (oxypropylene) (CAS No. [16096-30-3]) and of hydrogenated bisphenol A (2,2-bis [4- (2,3-epoxypropoxy) cyclohexyl] propane, (CAS No. [13410-58-7]).

The epoxy (meth) acrylates preferably have a number average molecular weight M _n of 340 to 20,000, particularly preferably from 340 to 10,000 g / mol and very particularly preferably from 480 to 3000 g / mol; the content of (meth) acrylic groups is preferably 1 to 5, particularly preferably 2 to 4 per 1000 g of epoxy (meth) acrylate (determined by gel permeation chromatography with polystyrene as standard and tetrahydrofuran as eluent).

Particularly preferred compounds (AI)

Polyol (meth) acrylates, (meth) acrylates of alkoxylated polyols, polyesterol (meth) acrylates, polyol glycidyl ether (meth) acrylates and (meth) acrylates of glycidyl ethers of alkoxylated polyols.

Among the compounds (AI), those of the formulas are very particularly preferred

(I) R ⁱ - [0-Acr] _n (II) Rl- [0- (CHR ² -CHR ³ -0) _Itl -Acr] _n ,

(III) R ¹ - [0- (CHR -CHR ³ -0) _m -Y-0-Acr] _n ,

(IVa) R ¹ - [0- (CHR -CHR ³ -0) _m -CH ₂ -CH (OH) -CH ₂ -0-acr] _n ,

(IVb) R ¹ - [0- (CHR ² -CHR ³ -0) _m -CH ₂ -CH (OAcr) -CH ₂ -OH] _n ,

(Va) R ¹ - [0-CH ₂ -CH (OH) -CH ₂ -0-Acr] _n , (Vb) R ¹ - [0-CH ₂ -CH (OAcr) -CH ₂ -OH] _n ,

wherein

R ^{1 is} an n-times substituted, aliphatic, cycloaliphatic or aromatic organic group with 2 to 20 carbon atoms,

R ² and R ³ independently of one another are hydrogen or methyl, Y is a spacer group having 1 to 20 carbon atoms,

Acr an acrylic or methacrylic residue or a Michael addition product to an acrylic or methacrylic residue,

n is an integer between 2 and 10, preferably between 2 and 5, particularly preferably between 2 and 4 and in particular between 2 and 3, and

m is an integer between 0 and 100, preferably 0 and 50, particularly preferably between 1 and 30 and in particular between 2 and 20

mean.

Examples of n-valent alcohols, which form the basis for the n-times substituted organic group

Ethylene glycol, propylene glycol and their more highly condensed homologs, e.g. Diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol etc., 1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl- l, 5-pentanediol, alkoxylated phenolic compounds, such as ethoxylated or propoxylated bisphenols, trimethylolpropane, trimethylolethane, neopentylglycol, pentaerythritol, 2-methyl-l, 3-propanediol, glycerol, ditrimethylolpropane, dipentaerythritol, bisphenol A, bisphenol A, bisphenol B, bisphenol S, 2,2-bis (4-hydroxycyclohexyl) propane, 1,1-, 1,2-, 1,3- and 1,4-cyclohexanedimethanol, 1,2-, 1,3- or 1, 4-cyclohexanediol,

Sorbitol, Mannitol, Diglycerol, Threitol, Erythritol, Adonit (Ritbit), Arabit (Lyxit), Xylit or Dulcit (Galactit).

Y stands for example for a group of the formula

- (CO) -R ⁵ - (CO) -R ⁷ -,

in which R ⁵ and R ⁷ independently of one another denote a single bond or an alkylene or arylene radical having 1 to 18, preferably 2 to 10, particularly preferably 2 to 7 carbon atoms, for example cis-1, 2-ethenylene, .trans-1, 2 -Ethenylene, 1,2-ethylene, 1, 3-propylene, 1,4-butylene, 1,6-hexylene, 1, 10-decylene, 1, 2-phenylene, 1, 3-phenylene, 1, 4-phenylene , 4-carboxy-l, 3-phenylene, 2-carboxy-l, 4-phenylene, 4-carboxy-l, 2-phenylene, 1,2-, 1,3- or 1,4-cyclohexylene or 1,2 -Cyclohexenyls. If the group (CHR ² -CHR ³ -0-) _{m stands} for a mixed-ethoxylated / propoxylated group, the proportion of propoxylated groups, ie R ² or R ³ is methyl, is less than 50 mol%, preferably less than 20 mol%, based on the total number of ethylene oxide and propylene oxide groups, particularly preferably less than 10 mol% and very particularly preferably 0 mol%.

Among the compounds (AI), preference is given to those hydrophilic according to the invention which are capable of homogeneously dissolving at least 2% by weight of distilled water at 25 ° C., particularly preferably at least 5% by weight, very particularly preferably at least 10% by weight, in particular at least 15% by weight and exceptionally preferred at least 20% by weight.

Bisphenol A diglycidyl ether diacrylate is equally preferred.

Compounds (AI) are often used in a mixture with other polymerizable compounds having a plurality of copolymerizable, ethylenically unsaturated groups (A2) and / or with compounds (B) which serve as reactive diluents.

The further polymerizable compounds which can be used as (A2) and have one or more copolymerizable, ethylenically unsaturated groups are known per se, other than (meth) acrylate compounds as described in (A1).

These are preferably those which are able to dissolve less than 5% by weight of distilled water homogeneously at 25 ° C., particularly preferably less than 2% by weight.

Compounds (A2) with one or more copolymerizable, ethylenically unsaturated groups are, for example, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, norbornyl acrylate, stearyl acrylate, phenoxyethyl acrylate and the acrylate of trimethylolpropane formal.

The compounds (A2) can be, for example, uretha (meth) acrylates.

Urethane (meth) acrylates are e.g. obtainable by reacting polyisocyanates with hydroxyalkyl (meth) acrylates or (meth) acrylic acid and optionally chain extenders such as diols, polyols, diamines, polyamines or dithiols or polythiols.

The polyurethanes which can be used according to the invention as (A2) essentially contain as structural components: a) at least one organic aliphatic, aromatic or cycloaliphatic di-or polyisocyanate, b) at least one compound with at least one isocyanate-reactive group and at least one radically polymerizable unsaturated group and c) optionally at least one compound with at least two isocyanate-reactive groups ,

Component a) includes, for example, aliphatic, aromatic and cycloaliphatic di- and polyisocyanates with an NCO

Functionality of at least 1.8, preferably 1.8 to 5 and particularly preferably 2 to 4, as well as their isocyanurates, biurets, allophanates and uretdiones.

The diisocyanates are preferably isocyanates having 4 to 20 carbon atoms. Examples of customary diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradeca ethylene diisocyanate, tetra diisocyanate, tetramethyl diisocyanate, tetramethyl diisocyanate , 1,3- or 1,2-diisocyanatocyclohexane, 4,4'- or 2,4'-di (isocyanatocyclohexyl) ethane, l-isocyanato-3,3,5-trimethyl-5- (isocyanatomethyl) cyclohexane ( Isophorone diisocyanate), 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane or 2,4- or 2,6-diisocyanato-1-methylcyclohexane and aromatic diisocyanates such as 2,4- or 2,6-tolylene diisocyanate and their isomer mixtures, m- or p-xylylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane and their isomer mixtures, 1,3- or 1,4-phenylene diisocyanate, l-chloro-2,4,4-phenylene diisocyanate, 1,5- Naphthylend iisocyanate, diphenylene-4,4'-diisocyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 3-methyldiphenylmethane-4,4'-diisocyanate, tetramethylxylylene diisocyanate, 1,4-diisocyanate-benzene or diphenyl ether 4, '-diisocyanate.

Mixtures of the diisocyanates mentioned can also be present.

Hexa ethylene diisocyanate, 1,3-bis (isocyanato-methyl) cyclohexane, isophorone diisocyanate and di (isocyanatocyclohexyl) methane are preferred.

Suitable polyisocyanates are polyisocyanates containing isocyanurate groups, uretdione diisocyanates, polyisocyanates containing biuret groups, polyisocyanates containing urethane or allophanate groups, polyisocyanates containing oxadiazinetrione groups, uretonimine-modified polyisocyanates of linear or branched ten C ₄ -C ₂ n-alkylene diisocyanates, cycloaliphatic diisocyanates with a total of 6 to 20 C atoms or aromatic diisocyanates with a total of 8 to 20 C atoms or mixtures thereof.

The di- and polyisocyanates which can be used preferably have a content of isocyanate groups (calculated as NCO, molecular weight = 42) of 10 to 60% by weight, based on the di- and polyisocyanate (mixture), preferably 15 to 60% by weight and particularly preferably 20 up to 55% by weight.

Aliphatic or cycloaliphatic di- and polyisocyanates, e.g. the aliphatic or cycloaliphatic diisocyanates mentioned above, or mixtures thereof.

Are also preferred

1) Isocyanurate group-containing polyisocyanates of aromatic, aliphatic and / or cycloaliphatic diisocyanates. The corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanates and particularly those based on hexamethylene diisocyanate and isophorone diisocyanate are particularly preferred. The isocyanurates present here are in particular tris-isocyanatoalkyl or tris-isocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologues which have more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30% by weight, in particular 15 to 25% by weight, and an average NCO functionality of 3 to 4.5.

2) Uretdione diisocyanates with aromatically, aliphatically and / or cycloaliphatically bound isocyanate groups, preferably aliphatically and / or cycloaliphatically bound and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cyclic dimerization products of diisocyanates. The uretdione diisocyanates can be used in the preparations according to the invention as the sole component or in a mixture with other polyisocyanates, in particular those mentioned under 1).

3) Polyisocyanates containing biuret groups with aromatic, cycloaliphatic or aliphatic, preferably cycloaliphatic or aliphatic, isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or its mixtures with its higher homologues. This biuret polyisocyanates containing groups generally have an NCO content of 18 to 22% by weight and an average NCO functionality of 3 to 4.5.

4) Polyisocyanates containing urethane and / or allophanate groups with aromatically, aliphatically or cycloaliphatically bound, preferably aliphatically or cycloaliphatically bound, isocyanate groups, such as, for example, by reacting excess amounts of hexamethylene diisocyanate or of isophorone diisocyanate with polyhydric alcohols, such as, for example, Trimethylolpropane, neopentyl glycol, pentaerythritol, 1, 4-butanediol, 1, 6-hexanediol, 1, 3-propanediol, ethylene glycol, diethylene glycol, glycerol, 1, 2-dihydroxypropane or mixtures thereof can be obtained. These polyisocyanates containing urethane and / or allophanate groups generally have an NCO content of 12 to 20% by weight and an average NCO functionality of 2.5 to 3.

5) Polyisocyanates containing oxadiazinetrione groups, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such polyisocyanates containing oxadiazinetrione groups can be prepared from diisocyanate and carbon dioxide.

6) Uretonimine-modified polyisocyanates.

The polyisocyanates 1) to 6) can be used in a mixture, if appropriate also in a mixture with diisocyanates.

Compounds b) which have at least one group which is reactive toward isocyanate and at least one radical-polymerizable group are suitable as component b).

Groups reactive towards isocyanate can be, for example, -OH, -SH, -NH and -NHR ⁶ , where R ^{6 is} hydrogen or an alkyl group containing 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, iso-propyl, n -Butyl, isobutyl, SeJc-butyl or tert-butyl means.

Components b) can e.g. Monoesters of α, β-unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid,

Itaconic acid, fumaric acid, maleic acid, acrylamidoglycolic acid, methacrylamidoglycolic acid or vinyl ether with di- or polyols, which preferably have 2 to 20 C atoms and at least two hydroxyl groups, such as ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1, 3 Propylene glycol, l, l-dimethyl-l, 2-ethanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 2-methyl-l, 5-pentanediol, 2-ethyl-1, 4-butanediol, 1, 4-dimethylolcyclohexane, glycerol, Trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, ditrimethylolpropane, erythritol, sorbitol, poly-THF with a molecular weight between 162 and 2000, poly-1, 3-propanediol with a molecular weight between 134 and 400 or polyethylene glycol with a molecular weight between 238 and 458. Furthermore, esters or amides of (meth) acrylic acid with amino alcohols, for. B. 2-aminoethanol, 2- (methylamino) ethanol, 3-amino-l-propanol, l-amino-2-propanol or 2- (2-aminoethoxy) ethanol, 2-mercaptoethanol or polyaminoalkanes such as ethylenediamine or diethylenetriamine , or vinyl acetic acid can be used.

Unsaturated polyether or polyesterols or polyacrylate polyols with an average OH functionality of 2 to 10 are also suitable.

Examples of amides of ethylenically unsaturated carboxylic acids with amino alcohols are hydroxyalkyl (meth) acrylamides such as N-hydroxymethyl acrylamide, N-hydroxymethyl methacrylamide, N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, 5-hydroxy-3-oxapentyl (meth) acrylamide, N Hydroxyalkylcrotonamides such as N-hydroxymethylcrotonamide or N-hydroxyalkylmaleinimides such as N-hydroxyethylmaleinimide.

2-Hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, 1,5-pentanediol mono (meth) acrylate are preferably used, 1, 6-hexanediol mono (meth) acrylate, glycerol mono- and di (meth) acrylate, trimethylolpropane mono- and di (meth) acrylate, pentaerythritol ono-, di- and tri (meth) acrylate as well as 4-hydroxybutyl vinyl ether, 2 -Aminoethyl (meth) acrylate, 2-amino-propyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 4-amino-butyl (meth) acrylate, 6-aminohexyl (meth) acrylate, 2-thioethyl (meth ) acrylate, 2-aminoethyl (meth) acrylamide, 2-aminopropyl (meth) acrylamide, 3-aminopropyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-hydroxypropyl (meth) acrylamide or 3-hydroxypropyl (meth) acrylamide. 2-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- or

3-hydroxypropyl acrylate, 1, 4-butanediol monoacrylate and 3- (acryloyloxy) -2-hydroxypropyl methacrylate.

Component c) is a compound which has at least two groups which are reactive toward isocyanate, for example -OH, -SH, -NH or -NHR ⁴ , in which R ⁴ is, independently of one another, hydrogen, methyl, ethyl, isopropyl, n-propyl , n-butyl, iso-Bu- can mean tyl, sefc-butyl or tert-butyl.

These are preferably diols or polyols, such as hydrocarbon diols having 2 to 20 carbon atoms, e.g. Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,1-dimethylethane-1,2-diol, 1,6-hexanediol, 1,10-decanediol, bis- (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol , 1,2-, 1,3- or 1,4-cyclohexanediol, cyclooctanediol, norbornanediol, pinanediol, decalinediol, etc., their esters with short-chain dicarboxylic acids, such as adipic acid, cyclohexanedicarboxylic acid, their carbonates, prepared by reaction of Diols with phosgene or by transesterification with dialkyl or diaryl carbonates, or aliphatic diamines, such as methylene and isopropylidene bis (cyclohexylamine), piperazine, 1,2-, 1,3- or 1,4-diaminocyclohexane, 1,2- , 1,3- or 1,4-cyclohexane-bis- (methyla in), etc., dithiols or polyfunctional alcohols, secondary or primary amino alcohols, such as ethanolamine, diethanolamine, monopropanolamine, dipropanolamine etc. or thioalcohols, such as Thioethylene glycol.

Diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, pentaerythritol, 1,2- and 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 2-ethyl-1 are also conceivable. 4-butanediol, 1,2-, 1,3- and 1,4-dirnethylolcyclohexane, glycerin, trimethylolethane, trimethylolpropane, trimethylolbutane, dipentaerythritol, ditrimethylolpropane, erythritol and sorbitol, 2-aminoethanol, 3-amino-l- propanol, l-amino-2-propanol or 2- (2-aminoethoxy) ethanol, bisphenol A, or butanetriol.

Unsaturated polyether or polyesterols or polyacrylate polyols with an average OH functionality of 2 to 10 are also suitable, as are polyamines, e.g. Polymers containing polyethyleneimine or free amine groups, e.g. Poly-N-vinylformamide.

The cycloaliphatic diols, such as e.g. Bis- (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1,2-, 1,3- or 1-cyclohexanediol, cyclooctanediol or norbornanediol.

The polyurethanes which can be used according to the invention as (A2) are obtained by reacting components a), b) and c) with one another.

The molar composition a): b): c) per 3 mol reactive isocyanate groups in a) is usually as follows: b) 1.5-3.0, preferably 2.0-2.9, particularly preferably 2.0-2.5 and in particular 2.0-2.3 mol of isocyanate-reactive groups and

c) 0-1.5, preferably 0.1-1.0, particularly preferably 0.5-1.0 and in particular 0.7-1.0 mol of isocyanate-reactive groups.

It may also make sense not to react all isocyanate groups with groups of components b) and c) which are reactive toward isocyanate groups, e.g. if the hardening should not be done exclusively by radiation.

After the reaction of components a), b) and c), the urethane (meth) acrylates can still contain free isocyanate groups, but more than 70% of the isocyanate groups present in a) before the reaction are preferably completely reacted, particularly preferably more than 80%, entirely particularly preferably more than 90% and in particular more than 95%.

In this case, the proportion of components b) and c) is adjusted accordingly in accordance with the desired proportion of free isocyanate groups.

Furthermore, it may also be useful to use an excess of component c) in order to obtain free groups which are reactive toward isocyanate groups.

If this is desired, the same stoichiometry of c) results for component b) with the same composition:

c) 0.5-2.5, preferably 0.6-2.0, particularly preferably 1.0-1.5 and in particular 1.2-1.5 mol of isocyanate-reactive groups.

The general production of urethane (meth) acrylates is known per se to the person skilled in the art.

The urethane (meth) acrylates preferably have a number average molecular weight M _n of 500 to 20,000, in particular from 750 to 10,000, particularly preferably 750 to 3000 g / mol (determined by gel permeation chromatography with tetrahydrofuran and polystyrene as standard).

The urethane (meth) acrylates preferably have a content of 1 to 5, particularly preferably 2 to 4, moles of (meth) acrylic groups per 1000 g urethane (meth) acrylate.

Suitable reactive diluents (compounds (B)) are free-radically polymerizable compounds, preferably radiation-curable compounds, having an ethylenically unsaturated, copolymerizable group, or mixtures thereof.

Examples include α, ß-unsaturated carboxylic acids, C 1 -C ₂₀ alkyl (meth) acrylates, vinyl atenas with up to 20 C atoms, vinyl esters of carboxylic acids containing up to 20 C atoms, ethylenically unsaturated nitriles, vinyl ethers from 1 to Alcohols containing 10 carbon atoms and aliphatic hydrocarbons with 2 to 8 carbon atoms and 1 or 2 double bonds.

The term (meth) acrylic acid is used in the context of this document for acrylic acid and methacrylic acid.

Examples of α, β-unsaturated carboxylic acids which can be used are acrylic acid, methacrylic acid, maleic acid or its half-ester, 3-acrylic oxypropionic acid, maleic anhydride, fumaric acid or its half-ester or crotonic acid.

Preferred (meth) acrylic acid alkyl esters are those having a C 1 -C 8 -alkyl radical, such as methyl methacrylate, methyl acrylate and ethyl acrylate.

Mixtures of the (meth) acrylic acid alkyl esters are also particularly suitable.

Vinyl esters of carboxylic acids with 1 to 20 C atoms are e.g. Vinyl laurate, vinyl stearate, vinyl propionate and vinyl acetate.

As vinyl aromatic compounds e.g. Vinyl toluene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene and preferably styrene are considered.

Examples of nitriles are acrylonitrile and methacrylonitrile.

Suitable vinyl ethers are e.g. Vinyl methyl ether, vinyl isobutyl ether, vinyl hexyl ether and vinyl octyl ether.

Butadiene, isoprene, as well as ethylene, propylene and isobutylene may be mentioned as non-aromatic hydrocarbons with 2 to 8 carbon atoms and one or two olefinic double bonds.

N-vinylformamide, N-vinylpyrrolidone and N-vinylcaprolactam can also be used. Preferred compounds (B) are acrylic acid esters and α, β-unsaturated carboxylic acids.

Those compounds (B) which are particularly preferred are those which

Capable of homogeneously dissolving at least 10% by weight of distilled water at 25 ° C., particularly preferably at least 20% by weight and very particularly preferably at least 50% by weight.

Photoinitiators known to those skilled in the art can be used as photoinitiators (C), e.g. those in "Advances in Polymer Science", Volume 14, Springer Berlin 1974 or in K.K. Dietiker, Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints, Volume 3; Photoinitiators for Free Radical and Cationic Polymerization, P.K.T. Oldring (Eds), SITA Technology Ltd, London.

For example, mono- or bisacylphosphine oxides such as are described in EP-A 7 508, EP-A 57 474, DE-A 196 18 720, EP-A 495 751 or EP-A 615 980, for example 2.4 , 6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO), ethyl 2, 4, 6-trimethylbenzoylphenylphosphinate, Irgacure® 819 from Ciba Specialty Chemicals (bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide), benzophenone, hydroxyacetophenone, hydroxyacetophenone xylic acid and its derivatives or mixtures of these photoinitiators. Examples include benzophenone, acetophenone, acetone naphthoquinone, methylethyl ketone, valerophenone, hexanophenone, α-phenylbutyrophenone, p-morpholinopropiophenone, dibenzosuberon, 4-morpholinobenzophenone, 4-morpholinodeoxybenzyl, pinophenonylbenzyl, p '-Methoxyacetophenone, ß-methylanthraquinone, tert-butylanthraquinone, anthraquinonecarboxylic acid ester, benzaldehyde, tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 10-thioxanthenone, 3-acetylphenanthrene, 3-acetylindole, 9-fluoro-non, 1 , 3, 4-triacetylbenzene, thioxanthene-9-one, xanthen-9-one, 2, 4-dimethylthioxanthone, 2, 4-diethylthioxanthone, 2, 4-di-iso-propylthioxanthone, 2, 4-dichlorothioxanthone, benzoin , Benzoin iso-butyl ether, chloroxanthenone, benzoin tetrahydropyra- nyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin iso propyl ether, 7-H-benzoin methyl ether, benz [de] anthracen-7 -one, 1-naphthaldehyde, 4,4'-bis (dimethylamino) benzophenone, 4-phenylbenzophenone, 4- Chlorobenzophenone, Michler's ketone, 1-acetonaphthone, 2-acetonaphthone, 1-benzoylcyclohexan-1-ol, 2-hydroxy-2, 2-dimethylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2, 2-diethoxy -2-phenylacetophenone, 1, 1-dichloroacetophenone, 1-hydroxyacetophenone, acetophenone dimethyl ketal, o-methoxybenzophenone, triphenylphosphine, tri-o-tolylphosphine, benz [a] anthracen-7, 12-dione, 2, 2-diethoxyacethen . Benzil ketals such as benzil dimethyl ketal, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-l-one, anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1- Chloroanthraquinone, 2-amylanthraquinone and 2, 3-butanedione.

Non-yellowing or little yellowing photoinitiators of the phenylglyoxalic acid ester type are also suitable, as described in DE-A 198 26 712, DE-A 199 13 353 or WO 98/33761.

Preferred among these are the listed acylphosphine oxides, benzophenones, hydroxyacetophenones and phenylglyoxylic acids.

In particular, mixtures of different photoinitiators can also be used.

Installable photoinitiators can also be used. Installable photoinitiators have polymerizable groups bonded to the basic photoinitiator structure via spacer groups. Such built-in photoinitiators are described, for example, in DE-A 195 24 812, EP-A 281 941, WO 00/24527. Preferred among these are 4-acryloxy-2'-chlorobenzophenone, 4-acryloxy-3'-chlorobenzophenone, 4-acryloxy-4'-chlorobenzophenone, 4- (6'-acrylic-oxy-2 '-oxa-1' -oxo-hexyloxy) benzophenone or 1, l-dimethyl-l-hydroxy- '- (2' '-acryloxyethoxy) -acetophenone.

The photoinitiators can be used alone or in combination with a photopolymerization promoter, e.g. of the benzoic acid, amine or similar type can be used.

Additives (D) include, for example, antioxidants, oxidation inhibitors, stabilizers, activators (accelerators), fillers, pigments, dyes, degassing agents, brighteners, antistatic agents, flame retardants, thickeners, thixotropic agents, flow control agents, binders, antifoams, fragrances, surface-active agents , Viscosity modifiers, plasticizers, plasticizers, tackifying resins (tackifiers), chelating agents or compatibilizers.

Furthermore, one or more initiators which can be activated photochemically and / or thermally can be added, for example potassium peroxodisulfate, dibenzoyl peroxide, cyclohexanone peroxide, di-tert.-butyl peroxide, azobis-isobutyronitrile, cyclohexylsulfonylacetyl peroxide, di-isopropyl percarbonate, f -Butyl peroctoate or benzopinacol, as well as, for example, those thermally activatable initiators which have a half-life at 80 ° C. of more than 100 hours, such as di-t-butyl peroxide, cumene hydroperoxide, dicumyl per- oxide, t-butyl perbenzoate, silylated pinacoles, e.g. B. are commercially available under the trade name ADDID 600 from Wacker or amine N-oxides containing hydroxyl groups, such as 2, 2, 6, 6-tetra-methylpiperidine-N-oxyl, 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-N-oxyl etc.

Further examples of suitable initiators are described in "Polymer Handbook", 2nd edition, Wiley & Sons, New York.

In addition to radical (co) polymerized thickeners

(Co) polymers, conventional organic and inorganic thickeners such as hydroxyethyl cellulose or bentonite.

As chelating agents e.g. Ethylenediamine acetic acid and its salts and β-diketones are used.

Suitable fillers include silicates, e.g. B. by hydrolysis of silicon tetrachloride available silicates such as Aerosil from Degussa, silica, talc, clay, mica, aluminum silicates, magnesium silicates, calcium carbonates, calcium and barium sulfates, aluminum hydroxides and oxides etc. or organic fillers such as e.g. Polyacrylic acids, for example with a molecular weight between 2000 and 300000, or cellulose.

Suitable stabilizers include typical UV absorbers such as oxanilides, Tπazme and Benzotπazol (the latter available as Tmuvm brands from Ciba specialty chemistry) and Benzophenone. These may be used alone or together with suitable free-radical scavengers, examples being sterically hindered amines such as 2, 2, 6, 6-tetra- ^{'methylpiperidine,} 2, 6-di-tert. -butylpiperidine or its derivatives, e.g. B. bis- (2, 2, 6, 6-tetra-methyl-4-piperidyl) sebacinate can be used. Stabilizers are usually used in amounts of 0.1 to 5.0% by weight, based on the solid components contained in the preparation.

Other suitable stabilizers are, for example, N-oxyls, such as 4-hydroxy-2, 2, 6, 6-tetramethyl-piperidine-N-oxyl, 4-oxo-2, 2,6, 6-tetramethyl-piperidine-N-oxyl , 4-acetoxy-2, 2,6, 6-tetramethyl-piperidine-N-oxyl, 2,2,6, 6-tetramethyl-piperidine-N-oxyl, 4, 4 ', 4''tris ( 2,2,6, 6-tetramethyl-piperidine-N-oxyl) phosphite or 3-oxo-2, 2.5, 5-tetramethyl-pyrrolidine-N-oxyl, phenols and naphthols, such as p-aminophenol , p-nitrosophenol, 2-tert. -Butylphenol, 4- e. -Butylphenol, 2, 4-di-ter. -Butylphenol, 2-methyl-4-tert. -Butylphenol, 4-methyl-2, 6-er. -Butylphenol (2,6-er.-Butyl-p-cresol) or 4-er. -Butyl-2, 6-dimethylphenol, quinones such as hydroquinone or hydroquinone monomethyl ether, aromatic amines such as N, N-diphenylamine, N-nitrosodipheny- lamin, phenylenediamines, such as N, N'-dialkyl-para-phenylenediamine, where the alkyl radicals can be the same or different and each independently consist of 1 to 4 carbon atoms and can be straight-chain or branched, hydroxylamines, such as N, N-diethylhydroxylamine, urea derivatives such as urea or thiourea, phosphorus-containing compounds such as triphenylphosphine, triphenylphosphite or triethylphosphite or sulfur-containing compounds such as diphenyl sulfide or phenothiazine.

Typical compositions for coating compositions (I) are, for example

(AI) 20-100% by weight, preferably 40-90, particularly preferably 50-90 and in particular 60-80% by weight,

(A2) 0-80% by weight, preferably 0-60, particularly preferably 0-50 and in particular 0- = ^" 40% by weight, (B) 0-70% by weight, preferably 5-50, particularly preferably 6-40 and in particular 10 - 30% by weight, (C) 0 - 20% by weight, preferably 0.5 - 15, particularly preferably 1 - 10 and in particular 2 - 5% by weight and (D) 0 - 50% by weight, preferably 2 - 40, particularly preferably 3 - 30 and in particular 5 - 20% by weight,

with the proviso that (AI), (A2), (B), (C) and (D) together make up 100% by weight.

Preferred among these are coating compositions (I) in which (Al) and (A2) and (B) together can dissolve at least 2% by weight of distilled water homogeneously, particularly preferably at least 5% by weight, very particularly preferably at least 10, in particular at least 15 wt%, and exceptionally preferably at least 20 ^"wt%.

To prepare the mixtures according to the invention, components (AI), (A2), (B), (C) or (D), but also (I), if appropriate, can be dispersed in a suitable solvent (III).

Dispersion is used in this document as a generic term according to Rö pp Chemie Lexikon - CD Version 1.0, Stuttgart / New York: Georg Thieme Verlag, 1995, and includes emulsions, suspensions and solutions.

Suitable solvents (III) are, for example, water, methanol, ethanol, isopropanol, n-propanol, n-butanol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, Ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, acetone, isobutyl methyl ketone, diethyl ketone,. Dimethylformamide, dimethyl sulfoxide, dioxane, tetrahydrofuran, tert-butyl methyl ether, tert-butyl ethyl ether, toluene, xylene, pentane, hexane, methyl acetate, ethyl acetate, butyl acetate,

Methyl propionate, ethyl propionate, butyl propionate, ethylene carbonate, 1, 2-propylene carbonate or 1, 3-propylene carbonate, water is preferred.

(I) and optionally components (AI), (A2), (B), (C) and / or (D) can be dispersed in the solvent (III). The proportion of (III) in the respective solution is determined by its solution properties. It can be between 10 and 99% by weight, preferably between 20 and 98% by weight and particularly preferably between 30 and 95% by weight.

The mixtures according to the invention are prepared by intimately mixing components (I), or their individual components (A) to (D), and, if appropriate, the solvent (III) in any order. If necessary, this can be done under protective gas.

The temperature during production is not restricted and is generally limited by the freezing or glass transition temperature and by the boiling point or the curing temperature of the respective components or mixtures. For example, the temperature is from 0 ° C to 80 ° C, preferably from 10 ° C to 70 ° C and particularly preferably from 20 ° C to 60 ° C.

The coating materials (I) are coated with the coating materials by customary methods known to the person skilled in the art, at least one mixture according to the invention, for example in the form of a dispersion or without solvent (III), onto the substrate to be coated in the desired

Starch is applied and the volatile constituents of the dispersion are removed, if appropriate with heating. If desired, this process can be repeated one or more times.

The application to the carrier material can in a known manner, for. B. by spraying, spraying, dipping, filling, knife coating, air blade, brushing, rolling, rolling or pouring, or using the so-called reverse gravure process.

In order to improve the adhesion on the film even further, the carrier film can be subjected to a corona treatment beforehand. The coating thickness is generally in a range from about 2 to 500 g / m ² and preferably 2 to 100 g / m ² . Films are coated in particular with quantities of up to 50, preferably 1-20 and particularly preferably between 1 and 10 g / m ² , papers, cardboards and cartons with quantities between 2 and 30, preferably 10 to 20 g / m ² (calculated in each case without Solvent (III)).

After the polymer dispersion has been applied to the flat substrates. the solvent (III) evaporates. For this purpose, the carrier film can be passed through a dryer channel, for example, in the case of continuous work, which can be equipped with an infrared radiation device. The coated and dried film is then passed over a cooling roll and finally wound up. The thickness of the dried coating is preferably up to 50 µm, particularly preferably 1 to 20 and very particularly preferably 1-10 µm.

The preferred viscosity of the coating compositions (I) is not limited per se, but is determined by the chosen method of application at the respective application temperature. For example, when applied over rollers, it should generally not be more than 500 mPas. When applying using a doctor blade, 1000 mPas should not be exceeded. In the case of rolling, rolling or casting, the viscosity is preferably set so that a continuous, continuous film is obtained on the support.

Furthermore, a method for coating carrier materials is disclosed, in which a coating composition (I), onto which carrier material is applied, optionally dried, thermally treated at the curing temperature indicated above and then, if appropriate at temperatures up to the curing temperature, with electron beams or UV Exposure cures under an oxygen-containing atmosphere or preferably under an inert gas.

The method of coating of substrates may also be carried out so that cured after application of the coating composition initially with electron ^beams' or UV exposure under oxygen or, preferably, under inert gas and subsequently at the curing temperature is thermally treated.

Thermal and radiation curing can of course also take place in parallel.

If desired, the films formed on the carrier material can only be cured thermally. In general, however, the coatings are cured both by irradiation treatment with high-energy radiation as well as thermally, or only by radiation.

If necessary, if several layers of the coating agent are applied one on top of the other, thermal and / or radiation curing can take place after each coating process.

The finished coating has a glass transition temperature above the usage temperature, usually above room temperature.

Furthermore, the coating of carrier materials can also be carried out as follows, where:

i) coating a carrier material with a coating composition, as described above,

ii) volatile constituents of the coating composition are removed for film formation under conditions in which the initiator (C) essentially does not yet form any free radicals,

iii) optionally irradiating the film formed in step ii) with high-energy radiation, the film being prehardened, and then, if appropriate, mechanically processing the object coated with the prehardened film or bringing the surface of the precured film into contact with another substrate,

iv) thermally cures the film.

Steps iv) and iii) can also be carried out in the reverse order. H. the film can first be cured thermally and then with high-energy radiation.

Typical curing temperatures for oriented polypropylene (OPP) are 40-120 ° C, preferably 50-110 ° C and particularly preferably 60-100 ° C. In the case of polyethylene films, the temperature should not exceed 80 ° C., preferably 60 ° C., in the case of paper, cardboard and cardboard the temperature can also be up to 150 ° C., preferably up to 140 ° C., particularly preferably from up to 120 and very particularly preferably be raised up to 100 ° C.

The temperature can remain the same or be raised during the course of the hardening process.

The curing time is usually between a few minutes and several hours, for example from 1 minute to 5 hours, preferably 2 minutes to 3 hours, particularly preferably 5 minutes to 2 hours and in particular from 10 minutes to 1 hour.

Examples of active energy rays are ultraviolet, X-ray and electron beams; ultraviolet and electron beams are preferred.

Suitable radiation sources for radiation curing are, for example, low-pressure mercury lamps, medium-pressure lamps and high-pressure lamps as well as fluorescent tubes, pulsed lamps, metal halide lamps, xenon lamps, electrodeless discharge lamps, carbon arc lamps, electron flash devices, which enables radiation curing without a photoinitiator, or radiation. Radiation curing is effected by the action of high-energy radiation, that is to say UV radiation or daylight, preferably light in the wavelength range from λ = 150 to 700 nm, particularly preferably from λ = 200 to 500 nm and very particularly preferably λ = 250 to 400 nm, or by irradiation with high-energy electrons (electron radiation; 50 to 1000 keV, preferably 100 to 500 and particularly preferably 150 to 300 keV) with devices, for example of the Cockroft-Walton type, van de Graaff type or resonance type. High-pressure mercury vapor lamps, lasers, pulsed lamps (flashing light), halogen lamps or excimer lamps are used as radiation sources, for example. The radiation dose usually sufficient for crosslinking in UV curing is in the range from 80 to 3000 mJ / cm ² .

Of course, several radiation sources can also be used for curing, e.g. two to four.

These can also radiate in different wavelength ranges.

The irradiation can optionally also be carried out with the exclusion of oxygen, e.g. B. are carried out under an inert gas atmosphere. Suitable inert gases are preferably nitrogen, noble gases, carbon dioxide or combustion gases. Irradiation can also be carried out by covering the coating material with transparent media. Transparent media are e.g. B. plastic films, glass or liquids, eg. B. water. Irradiation in the manner as described in DE-A 199 57 900 is particularly preferred.

Another preferred form of coating and curing is the application of the coating materials between two carrier materials, at least one of which is transparent to the radiation used for radiation curing. The loading Layering compound also act as a lamination adhesive.

The substrates coated with the coating composition show an excellent barrier effect against oxygen, even when exposed to moisture. The coated substrates can be used as such as packaging. The coatings have very good mechanical properties and show e.g. Gloss, transparency and good blocking behavior and show essentially no cracking.

To obtain ^'special surface or coating properties of the packaging means, for example, good printability, even better sealing and blocking behavior, good water resistance, it can be advantageous to exceed the barrier zubeschichten with the oxygen coated substrates with cover layers that give these desired properties in addition. The substrate pre-coated with the oxygen barrier shows good top coatability. It can be overcoated again using a method mentioned above, or it can be coated several times in a continuous process without intermediate winding and unwinding, for example the film. The oxygen barrier layer is thus inside the system, the surface properties are then determined by the top layer. The top layer adheres well to the oxygen barrier layer.

According to the described method, oxygen-impermeable coatings can be easily applied to the carrier materials mentioned at the beginning, e.g. on films made of oriented polypropylene or polyethylene, the polyethylene having been produced both by the high pressure and by the low pressure polymerization processes of ethylene. Other suitable carrier films are, for example, films made of polyester, such as polyethylene terephthalate, films made of polyamide, polystyrene and polyvinyl chloride. Papers and metal foils such as aluminum foil are also suitable as carrier foils. The thickness of the carrier films is generally in the range from 10 to 200 μm, for films made of polyamide 30 to 50 μm, for films made of polyethylene terephthalate 10 to 40 μm, for films made of polyvinyl chloride about 200 μm and for films made of polystyrene at around 20 μm.

The coated carrier material system according to the invention generally has an oxygen permeability below 100 cm ³ / (m ² xdx bar) based on 100 μm, particularly preferably below 50 and very particularly preferably below 20 and in particular below 10. Furthermore, the coated film systems according to the invention act as fat barriers against migration of fats, oils and waxes through the coated film system, and as aroma barriers against the migration of aroma substances, especially terpenes and terpenoid flavors and aroma substances.

The coating can equally improve water resistance, gloss, non-blocking, sliding behavior, hardness and bondability. For this purpose, additives (D) known per se to the person skilled in the art can optionally be added to the coating composition (I).

The coatings of the invention are water resistant, i.e. they show on contact with moisture, e.g. in the Cobb test (DIN 53132), no detachment or stickiness.

The coated carrier materials according to the invention are particularly suitable as packaging systems, particularly preferably in the food sector.

For packaging materials used in the food sector, the coating is preferably on the side facing outwards, i.e. on the side facing away from the food.

The carrier material can be coated in another way before or after the coating, e.g. be printed. If desired, after coating with the coating composition (I) e.g. there is a gloss coating.

The following examples are intended to illustrate the properties of the invention, but without restricting it.

Examples

Unless otherwise stated, "parts" in this document are understood to mean "parts by weight".

The coating compositions used in the examples and comparative examples were solvent-free, i.e. used as 100% systems. 4% by weight of Irgacure® 184 from Ciba Specialty Chemicals were used as photoinitiators. The UV radiation was carried out using a system from the IST company using a medium-pressure mercury lamp with an output of 120 W / cm and a distance of 15 cm from the substrate at a belt feed of 5 m / min.

The oxygen permeability was determined on coatings on a oriented polypropylene film determined at 0% relative humidity. First, the oxygen permeability is measured, which is then converted to a layer thickness of 100 μm and specified as oxygen permeability with the unit cm ³ / (m ² xdx bar), where d is the time in days. The determination is based on ASTM-D 3985-81.

Comparative Example 1

Urethane acrylate of average molecular weight 3000 g / mol based on isophorone diisocyanate, tripropylene glycol and hydroxyethyl acrylate, mixed with tripropylene glycol diacrylate.

example 1

Polyether acrylate based on trimethylolpropane, reacted with approx. 3 equivalents of propylene oxide and 0.5 equivalents of ethylene oxide, amine-modified with 4% by weight of monoethanolamine.

Example 2

100% by weight 1,4-butanediol diglycidyl ether diacrylate

Example 3

The aliphatic urethane acrylate from Comparative Example 1 was mixed 1: 1 (w / w) with acrylic acid.

Example 4

55% by weight of bisphenol A diglycidyl ether diacrylate and 45% by weight of the triacrylate of triple ethoxylated trimethylolpropane (product of the reaction of 3 mol of ethylene oxide with 1 mol of trimethylolpropane).

Claims

claims

1. A process for the production of packaging materials with 5 oxygen barrier properties, characterized in that a

Containing carrier material with a coating agent (I)

(AI) at least one polymerizable compound having one or more copolymerizable, ethylenically unsaturated groups,

(A2) optionally at least one further polymerizable compound having one or more copolymerizable, ethylenically unsaturated groups, 15

(B) optionally reactive diluents containing a copolymerizable, ethylenically unsaturated group,

(C) optionally photoinitiator and 20

(D) optionally further additives,

coated and then hardened.

25 2. The method according to claim 1, characterized in that the coating composition (I) is radiation-hardened.

3. The method according to any one of the preceding claims, characterized in that (AI) is selected from compounds of the formula 30

(I) Ri-tO-Acr n

(II) R ¹ - [0- (CHR ² -CHR ³ -0) _m -Acr] _n , 35

(III) R ¹ - [O- (CHR -CHR -0) _m -Y-0-Acr] _n ,

(IVa) R ¹ - [0- (CHR ² -CHR ³ -0) _m -CH ₂ -CH (OH) -CH ₂ -0-acr] _n ,

-40 (IVb) R ¹ - [0- (CHR ² -CHR ³ -0) _m -CH ₂ -CH (OAcr) -CH ₂ -OH] _n ,

(Va) R ¹ - [0-CH ₂ -CH (OH) -CH ₂ -0-acr] _n ,

(Vb) R ¹ - [0-CH ₂ -CH (OAcr) -CH ₂ -OH] _n ,

45 where R ^{1 is} an n-times substituted, aliphatic, cycloaliphatic or aromatic organic group with 2 to 20 carbon atoms,

R ² and R ³ independently of one another are hydrogen or methyl,

Y is a spacer group having 1 to 20 carbon atoms,

Acr an acrylic or methacrylic residue or a Michael addition product to an acrylic or methacrylic residue,

n is an integer between 2 and 10 and

m is an integer between 0 and 100

mean.

4. The method according to any one of claims 1 to 3, characterized in that at 25 ° C.

(AI) at least 5% by weight,

(A2) less than 5% by weight,

(B) at least 10% by weight and

(AI), (A2) and (B) together at least 5% by weight

are able to dissolve distilled water homogeneously.

5. Coating composition (I) containing

(AI) at least one polymerizable compound with one or more copolymerizable, ethylenically unsaturated groups,

(A2) optionally at least one further polymerizable compound having one or more copolymerizable, ethylenically unsaturated groups,

(B) optionally reactive diluents containing a copolymerizable, ethylenically unsaturated group,

(C) optionally photoinitiator and

(D) optionally further additives, with the proviso that at 25 ° C

(AI) at least 5% by weight,

(A2) less than 5% by weight,

(B) at least 10% by weight and

(AI), (A2) and (B) together at least 5% by weight

are able to dissolve distilled water homogeneously.

6. The method according to any one of claims 1 to 4 or coating composition according to claim 5, characterized in that (AI) is selected from bisphenol A diglycidyl ether (meth) acrylate, bisphenol F diglycidyl ether, 1,4-butanediol diglycidyl ether, 1, 6-hexanediol diglyoidyl ether, trimethylolpropane triglycidyl ether or pentaerythritol tetraglycidyl ether.

7. Packaging means, characterized in that a carrier material is coated by a process according to one of claims 1 to 4 or 6.

8. Packaging means according to claim 7, characterized in that cardboard, paper, cardboard, plastic or metal foil is used as the carrier material.

9. Use of packaging materials according to claim 7 or 8 for packaging food.

10. Use of radiation-curable coating compositions as an oxygen barrier.