Two-component lamination adhesive

Abstract

Described is a two-component lamination adhesive, wherein the first component of the lamination adhesive comprises dispersed particles of two polymers, a first polymer being producible by free-radical emulsion polymerization of specific ethylenically unsaturated, free-radically polymerizable monomers and a second polymer is a polyurethane; wherein the second component of the lamination adhesive comprises a crosslinking compound.

Description

[0001] Two-component lamination adhesive

[0002] Description

[0003] The invention relates to a two-component lamination adhesive, wherein one component of the lamination adhesive comprises dispersed particles of two polymers, a first polymer being producible by free-radical emulsion polymerization of specific ethy lenical ly unsaturated, free-radical ly polymerizable monomers and a second polymer is a polyurethane; wherein the second component of the lamination adhesive comprises a crosslinking compound. The invention also relates to a process of lamination using said lamination adhesive and to articles produced by said process.

[0004] It is known that aqueous lamination adhesives can be based on aqueous dispersions of adhesive polyacrylates or on aqueous dispersions of adhesive polyurethanes. The lamination adhesives can be used for making film-to-film laminates or film-to-paper laminates. Lamination adhesives based on specific polyacrylates are for example described in WO 98 / 23656 A1 and in WO 00 / 50480. Lamination adhesives based on specific, low-urea polyurethanes are for example described in WO 2006 / 087317 A2. Lamination adhesives based on polyurethanes are often superior and therefore preferred over lamination adhesives based on polyacrylates due to better adhesive performance of the polyurethane lamination adhesives, e.g. in terms of instant peel forces at room temperature and of peel forces at higher temperatures.

[0005] However, polyurethane with good peel force performance and sufficiently low glass transition temperatures typically form relatively soft adhesive films on polymeric carrier film substrates or on carrier paper substrates. Soft polyurethane adhesive films may lead to roll winding defects known as "telescoping” when the coated carriers are wound into a roll for storage, transportation and later further use or when unwound for further processing of the rolls for producing flexible packaging.

[0006] Telescoping is the effect of forming convex / concave rolls when the carrier web is wound into a roll due to an abrupt lateral movement of a portion of the roll and slippage of the coated carrier layers. This roll winding defect has a classic concave or convex roll shape caused by progressive misalignment of the roll edges. It is often encountered in winding of film laminates for producing flexible packaging or may only be noticed after the roll has started to unwind. Defects in the laminate rolls have serious consequences for further processing of the rolls for producing flexible packaging.

[0007] The object was to provide lamination adhesives with the good adhesive performance of polyurethane-based lamination adhesives, in particular sufficiently high instant peel force at room temperature and sufficiently high peel force at elevated temperatures (e.g. at about 65 °C), but at the same time significantly minimizing or avoiding the risk of roll winding defects such as telescoping of the produced laminates. It has now been found that the problem can be solved by the two-component lamination adhesive as claimed and described herein below.

[0008] The invention provides a two-component lamination adhesive, wherein one component of the lamination adhesive is in the form of an aqueous polymer dispersion comprising dispersed polymer particles of

[0009] (i) at least one first polymer which is producible by free-radical emulsion polymerization of ethy lenically unsaturated, free-radically polymerizable monomers comprising

[0010] (a) at least 49%, preferably from 50 to 90% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of C2- to C 12-alkyl acrylates and C2- to C12-alkyl methacrylates;

[0011] (b) 5 to 50%, preferably from 9 to 40% by weight, based on the total amount of monomers, of styrene;

[0012] (c) 0.1 to 10%, preferably from 0.5 to 10% by weight, based on the total amount of monomers, of at least one hydrophilic ethy lenical ly unsaturated monomer with at least one hydrophilic group selected from acid groups and hydroxy groups

[0013] (d) 0 to 10% by weight, based on the total amount of monomers, of at least one further ethylenically unsaturated monomer distinct from the monomers a), b) and c), wherein the glass transition temperature of the first polymer is more than minus 30 °C, preferably at least minus 25 °C, more preferably from minus 25 to + 5 °C, measured by differential scanning calorimetry at a heating rate of 20°C / min; and

[0014] (ii) at least one second polymer which is an adhesive polymer selected from polyurethanes; and wherein the second component of the lamination adhesive comprises a crosslinking compound capable of crosslinking the first component.

[0015] The invention also provides a process for lamination, in which two substrates are bonded together wherein a) a first substrate in the form of a first film or paper is provided, b) a second substrate is provided, selected from paper or a second film that may be the same or different from the first film, c) the two-component adhesive according to the invention is provided, and d) the two-component adhesive is applied onto the first substrate and / or onto the second substrate, optionally being allowed to dry, and the first substrate is laminated onto the second substrate.

[0016] The invention also provides a laminated product produced according to said process.

[0017] The invention also provides for the use of the two-component lamination adhesive as described herein for film-to-film lamination or for film-to-paper lamination. The text below occasionally uses the designation "(meth)acrylic” or "(meth)acrylate” and similar as an abbreviating notation for "acrylic or methacrylic” or "acrylate or methacrylate”. In the designation Cx-alkyl (meth)acrylate and analogous designations, x denotes the number of carbon atoms in the alkyl group.

[0018] The glass transition temperature is determined by differential scanning calorimetry (ASTM D 3418-08, so-called midpoint temperature). The glass transition temperature of the polymer in the polymer dispersion is the glass transition temperature obtained when evaluating the second heating curve (heating rate 20°C / min).

[0019] Molecular weight of polymeric diols is number average molecular weight, calculated from the OH-number, measured according to DIN 53240.

[0020] The aqueous laminating adhesive preferably comprises from 30% to 60% by weight, particularly preferably from 40% to 55% by weight, of the total of first and second polymers. The weight ratio of first polymer to second polymer is preferably from 1 :2 to 2:1, more preferably from 1:1.5 to 1.5:1.

[0021] The aqueous laminating adhesive comprises at least one first adhesive polymer which is producible by free-radical emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers, also referred to hereinbelow as acrylic emulsion polymer. This emulsion polymer is dispersed in the laminating adhesive composition. This adhesive polymer has a glass transition temperature of more than minus 30 °C, preferably at least minus 25 °C, more preferably from minus 25 to + 5 °C, measured by differential scanning calorimetry at a heating rate of 20°C / min. The glass transition temperature can be adjusted by using the appropriate monomers a) to d) as is known by the person skilled in the art.

[0022] Monomers (a)

[0023] The first polymer, the acrylic emulsion polymer, is made of (a) at least 49%, preferably from 50 to 90% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of C2- to C12- alkyl acrylates and C2- to C12-alkyl methacrylates. Preferred monomers (a) are C2- to C8-alkyl acrylates, C2- to C8- alkyl methacrylates and mixtures thereof. Preferred monomers (a) are one or multiple monomers selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2-propylheptyl acrylate. In particular, mixtures of the (meth)acrylic acid alkyl esters are also suitable. Especially particularly preferred are ethyl acrylate, n-butyl acrylate, n-butyl methacrylate, n-hexyl acrylate, 2-octyl acrylate and 2-ethylhexyl acrylate.

[0024] Monomer (b)

[0025] The first polymer, the acrylic emulsion polymer, is made of (b) 5 to 50%, preferably from 9 to 40% by weight, based on the total amount of monomers, of styrene. Monomer (c)

[0026] The first polymer, the acrylic emulsion polymer, is made of (c) 0.1 to 10%, preferably from 0.5 to 10% by weight, based on the total amount of monomers, of at least one hydrophilic ethy lenically unsaturated monomer with at least one hydrophilic group selected from acid groups and hydroxy groups. Monomers (c) with at least one acid group are preferably used in amounts of 0.5 to 6% by weight, based on the total amount of monomers. Monomers (c) with at least one hydroxy group are preferably used in amounts of 1 to 10% by weight, based on the total amount of monomers.

[0027] The monomers (c) with acid groups comprise not only monomers comprising at least one acid group but also anhydrides thereof and salts thereof. The monomers (c) include alpha, beta-monoethylenically unsaturated monocarboxylic and dicarboxylic acids, half-esters of alpha, beta-monoethylenically unsaturated dicarboxylic acids, the anhydrides of the abovementioned alpha, beta-monoethylenically unsaturated carboxylic acids and also ethy lenical ly unsaturated sulfonic acids, phosphonic acids or dihydrogenphosphates and water-soluble salts thereof, for example alkali metal salts thereof. Examples thereof are acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylacetic acid and viny llactic acid. Examples of suitable ethy lenical ly unsaturated sulfonic acids include vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, sulfopropyl acrylate and sulfopropyl methacrylate. Monomers (c) with at least one acid group are preferably selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylacetic acid, viny llactic acid, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, sulfopropyl acrylate, sulfopropyl methacrylate and mixtures of these monomers. More preferred monomers (c) are alpha, beta- monoethylenically unsaturated C3-C8-carboxylic acids and C4-C8-dicarboxylic acids, for example itaconic acid, crotonic acid, vinylacetic acid, acrylamidoglycolic acid, acrylic acid and methacrylic acid and also anhydrides thereof. Particularly preferred monomers (c) are itaconic acid, acrylic acid, methacrylic acid and mixtures thereof.

[0028] The acid groups of the monomer (c) may be present in unneutralized form at the beginning of the polymerization and may be fully or partially neutralized by feeding of a base during or after the emulsion polymerization, wherein for example the feeding of the base commences during the emulsion polymerization (i.e. after commencement of the polymerization reaction) once at least 5% by weight, preferably 10% to 70% by weight, of the total monomer mixture is present in the reaction vessel under polymerization conditions. The neutralizing agent may be added for example in a separate feed simultaneously with the feeding of the monomer mixture. After feeding of all of the monomers, the polymerization vessel preferably contains the amount of neutralizing agent required for neutralizing at least 10%, preferably 10% to 100% or 25% to 90%, of acid equivalents. Suitable bases are, for example, sodium hydroxide solution, potassium hydroxide solution, ammonia (preferably in aqueous solution) or organic amines, preferably tertiary amines, in particular trialkylamines preferably having 1 to 4 carbon atoms in the alkyl group, such as for example triethylamine.

[0029] Monomers (c) with at least one hydroxy group include, for example, the hydroxyalkyl esters of the abovementioned alpha, beta-monoethylenically unsaturated carboxylic acids, preferably hydroxyalkyl (meth)acrylates with 1 to 10 carbon atoms in the alkyl group. Preferred monomers (c) with at least one hydroxy group are selected from the group consisting of for example hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate and mixtures thereof.

[0030] Monomers (c) with acid groups and monomers with hydroxy groups can be used in combination, for example 0.5 to 6% by weight of one or more monomers with at least one acid group and 1 to 9.5% by weight of one or more monomers with at least one hydroxy group, for example acrylic acid and / or methacrylic acid in combination with at least one monomer selected from hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate.

[0031] Monomer (d)

[0032] The first polymer, the acrylic emulsion polymer, is made of (d) 0 to 10% by weight, based on the total amount of monomers, of at least one further ethy lenical ly unsaturated monomer distinct from the monomers (a), (b) and (c). The monomers (d) are preferably selected from the group consisting of methyl acrylate, methyl methacrylate, vinyl esters of carboxylic acids comprising up to 20 carbon atoms, vinylaromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols comprising 1 to 10 carbon atoms, aliphatic hydrocarbons having 2 to 8 carbon atoms and one or two double bonds, acrylamide, methacrylamide, C1-C10 aminoalkyl(meth)acrylates, nitriles of alpha, beta- monoethylenically unsaturated C3-C8 carboxylic acids, bifunctional monomers which as well as an ethylenical ly unsaturated double bond have at least one group selected from glycidyl group, oxazoline group, ureido group and, ureido-analogous group, and crosslinking monomers which have more than one radically polymerizable group, more particularly two or more (meth)acrylate groups and mixtures of these monomers. Vinyl esters of carboxylic acids having 1 to 20 carbon atoms are, for example, vinyl laurate, vinyl stearate, vinyl propionate, versatic acid vinyl esters, and vinyl acetate. Vinylaromatic compounds different from styrene include vinyltoluene, alpha- and paramethylstyrene, alpha-butylstyrene, 4-n-buty Isty rene and 4-n-decylstyrene. The vinyl halides are ethy lenically unsaturated compounds substituted by chlorine, fluorine or bromine, preferably vinyl chloride and vinylidene chloride. Examples of vinyl ethers include for example vinyl methyl ether or vinyl isobutyl ether. Vinyl ethers of alcohols comprising 1 to 4 carbon atoms are preferred. Hydrocarbons having 4 to 8 carbon atoms and two olefinic double bonds include butadiene, isoprene and chloroprene. Preferred monomers which have more than one free-radically polymerizable group are butanediol di(meth)acrylate or allyl methacrylate.

[0033] Examples of oxazoline group monomers are those of the formula: wherein the radicals are defined as follows: R is a C2-2o-alkeny I radical comprising at least one ethy lenically unsaturated group;

[0034] R3, R4, R5and R6are independently of one another selected from H, halogen, Ci-20-alkyl,

[0035] C2-2o-alkenyl, Ce-20-aryl, Cz-32-arylalkyl, Ci-20-hydroxyalkyl, Ci-20-aminoalkyl and Ci-20-haloalkyl, preferably selected from H, halogen and Ci-20-alkyl. The oxazoline monomers are especially preferably at least one monomer selected from the group consisting of 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-vinyl-4- ethyl-2-oxazoline, 2-vinyl-4,4-dimethyl-2-oxazoline, 2-vinyl-5,5-dimethyl-2-oxazoline, 2-vinyl-4,4,5,5-teramethyl-2- oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2- isopropenyl-4-ethyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-4,4-dimethyl-2-oxazoline, 2- isopropenyl-5,5-dimethyl-2-oxazoline and 2-isopropenyl-4,4,5,5-tetramethyl-2-oxazoline. The use of 2-vinyl-2- oxazoline and / or 2-isopropenyl-2-oxazoline is particularly preferred; 2-isopropenyl-2-oxazoline (iPOx) is especially preferred.

[0036] Examples of ureido group or ureido-analogous group monomers are, for example, those of the formula wherein X is CH2, 0, NH or NR1and R1is a C1- to C4-alkyl group, R is hydrogen or methyl, and A is a divalent linking group, preferably a C1- to C10-alkyl group or a C2- to C4-alkyl group. Particularly preferred are ureidoalkyl (meth)acrylates having 1 to 10 carbon atoms, preferably 2 to 4 carbon atoms, in the alkyl group, in particular ureidoethyl methacrylate (UMA).

[0037] Particularly preferred monomers (d) are methyl acrylate, methyl methacrylate and glycidyl methacrylate (ester of methacrylic acid and glycidol). Preferred is for example methyl (meth)acrylate in amounts of 1 to 10 wt.%, based on the total amount of monomers. Also preferred is for example glycidyl methacrylate in amounts of 1 to 4 wt.%, based on the total amount of monomers.

[0038] The first polymer of the two-component lamination adhesive is preferably producible by free-radical emulsion polymerization of ethy lenical ly unsaturated, free-radical ly polymerizable monomers comprising

[0039] (a) from 50 to 90% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tertbutyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2- propylheptyl acrylate;

[0040] (b) from 9 to 40% by weight, based on the total amount of monomers, of styrene;

[0041] (c) from 0.5 to 10% by weight, based on the total amount of monomers, of at least one hydrophilic ethylenically unsaturated monomer with at least one hydrophilic group selected from acid groups and hydroxy groups, wherein the hydrophilic monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylacetic acid, viny llactic acid, viny Isulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, sulfopropyl acrylate, sulfopropyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate, 4-hydroxy butyl acrylate and 4-hydroxybutyl methacrylate;

[0042] (d) 0 to 10% by weight, based on the total amount of monomers, of at least one further ethylenically unsaturated monomer distinct from the monomers a), b) and c).

[0043] In one embodiment, the first polymer of the two-component lamination adhesive is producible by free-radical emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers comprising

[0044] (a) from 50 to 90% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tertbutyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2- propylheptyl acrylate;

[0045] (b) from 9 to 40% by weight, based on the total amount of monomers, of styrene;

[0046] (c) from 0.5 to 6% by weight, based on the total amount of monomers, of at least one hydrophilic ethylenically unsaturated monomer selected from the group consisting of acrylic acid and methacrylic acid;

[0047] (d) 0 to 10% by weight, based on the total amount of monomers, of at least one further ethylenically unsaturated monomer distinct from the monomers a), b) and c).

[0048] In one embodiment, the first polymer of the two-component lamination adhesive is producible by free-radical emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers comprising

[0049] (a) from 50 to 85% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tertbutyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2- propylheptyl acrylate;

[0050] (b) from 9 to 40% by weight, based on the total amount of monomers, of styrene;

[0051] (c) from 2 to 6% by weight, based on the total amount of monomers, of at least one hydrophilic ethylenically unsaturated monomer selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate;

[0052] (d) 0 to 10% by weight, based on the total amount of monomers, of at least one further ethylenically unsaturated monomer distinct from the monomers a), b) and c).

[0053] In one embodiment, the first polymer of the two-component lamination adhesive is producible by free-radical emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers comprising (a) from 55 to 85% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tert- butyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2- propylheptyl acrylate;

[0054] (b) from 9 to 40% by weight, based on the total amount of monomers, of styrene;

[0055] (c) from 2 to 6% by weight, based on the total amount of monomers, of at least one hydrophilic ethylenically unsaturated monomer selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate; and no further ethylenically unsaturated monomer distinct from the monomers a), b) and c).

[0056] In one embodiment, the first polymer of the two-component lamination adhesive is producible by free-radical emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers comprising

[0057] (a) from 50 to 85% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tertbutyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2- propylheptyl acrylate;

[0058] (b) from 9 to 40% by weight, based on the total amount of monomers, of styrene;

[0059] (c) from 2 to 6% by weight, based on the total amount of monomers, of at least one hydrophilic ethylenically unsaturated monomer selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate;

[0060] (d) 1 to 4% by weight, based on the total amount of monomers, of glycidyl methacrylate.

[0061] The monomers of the polymerization for the first polymer are selected such that the measured glass transition temperature of the adhesive polymer is more than minus 30 °C, preferably at least minus 25 °C, more preferably from minus 25 to + 5 °C. Through targeted variation of monomer type and quantity, those skilled in the art are able according to the invention to produce aqueous polymer compositions whose polymers have a glass transition temperature in the desired range. Orientation is possible using the Fox equation. According to Fox (T.G. Fox, Bull. Am. Phys. Soc. 1956 [Ser. II] 1, page 123 and according to Ullmann's Encyclopedia of Industrial Chemistry, vol. 19, page 18, 4th edition, Verlag Chemie, Weinheim, 1980), the glass transition temperature of copolymers is given to a good approximation by:

[0062] 1 / Tg = X1 / Tg1+ X2 / Tg2+ .... Xn / Tgn, wherein x1, x2, .... xnare the mass fractions of the monomers 1, 2, .... n and Tg1, Tg2, .... Tgnare the glass transition temperatures in degrees kelvin of the polymers constructed from only one of the monomers 1, 2, .... n at a time. The Tgvalues for the homopolymers of the majority of monomers are known and are listed for example in Ullmann's Encyclopedia of Industrial Chemistry, vol. 5, vol. A21, page 169, VCH Weinheim, 1992; further sources for glass transition temperatures of homopolymers are, for example, J. Brandrup, E.H. Immergut, Polymer Handbook, 1stEd., J. Wiley, New York 1966, 2ndEd. J. Wiley, New York 1975, and 3rdEd. J. Wiley, New York 1989.

[0063] In one embodiment of the invention the free-radical polymerization employs at least one chain transfer agent. This makes it possible to reduce the molar mass and the gel content of the emulsion polymer through a chain termination reaction. The chain transfer agents are bonded to the polymer in this procedure, generally to the chain end. The amount of the chain transfer agents is especially 0.05 to 4 parts by weight, particularly preferably 0.05 to 0.8 parts by weight and very particularly preferably 0.1 to 0.6 parts by weight, based on 100 parts by weight of the monomers to be polymerized. Suitable chain transfer agents are, for example, compounds having a thiol group such as tert-butyl mercaptan, thioglycolic acid ethyl acryl ester, mercaptoethanol, mercaptopropyl trimethoxysilane or tert-dodecyl mercaptan. The chain transfer agents are generally compounds of low molecular mass, having a molar weight of less than 2000, in particular less than 1000 g / mol. Preferred are 2-ethylhexyl thioglycolate (EHTG), isooctyl 3- mercaptopropionate (IOMPA) and tert-dodecyl mercaptan (tDMK).

[0064] The polymerization may be carried out with seed control, i.e., in the presence of polymer seed (seed latex). Seed latex is an aqueous dispersion of finely divided polymer particles having an average particle diameter of preferably 20 to 40 nm. Seed latex is used in an amount of preferably 0.01 to 0.5 parts by weight, particularly preferably of 0.03 to 0.3 parts by weight, or of 0.03 to not more than 0.1 parts by weight based on 100 parts by weight of monomers. A latex based on polystyrene or based on polymethyl methacrylate is suitable for example. One preferred seed latex is polystyrene seed.

[0065] The emulsion polymerization comprises polymerizing ethylenically unsaturated compounds (monomers) in water using usually ionic and / or nonionic emulsifiers and / or protective colloids or stabilizers as surface-active compounds to stabilize the monomer droplets and the polymer particles subsequently formed from the monomers. The surfaceactive substances are typically used in amounts of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the monomers to be polymerized.

[0066] A detailed description of suitable protective colloids can be found in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], volume XIV / 1 , Makromolekulare Stoffe [Macromolecular Materials], Georg- Thieme-Verlag, Stuttgart, 1961 , p. 411 to 420. Useful emulsifiers include anionic, cationic and also nonionic emulsifiers. As surface-active substances it is preferable to employ emulsifiers whose molecular weight is typically below 2000 g / mol in contrast with the protective colloids. When mixtures of surface-active substances are used, the individual components must of course be compatible with one another; in case of doubt, this may be checked on the basis of a few preliminary experiments. Preference is given to using anionic and nonionic emulsifiers as surfaceactive substances. Customary accompanying emulsifiers are for example ethoxylated fatty alcohols (EC degree: 3 to 50, alkyl radical: Cs to C36), ethoxylated mono-, di- and trialkylphenols (EC degree: 3 to 50, alkyl radical: C4 to C9), alkali metal salts of dialkyl esters of sulfosuccinic acid and alkali metal and ammonium salts of alkyl sulfates (alkyl radical: Cs to C12), of ethoxylated alkanols (EC degree: 4 to 30, alkyl radical: C12 to G ), of ethoxylated alkylphenols (EO degree: 3 to 50, alkyl radical: C4 to C9), of alkylsulfonic acids (alkyl radical: C12 to G ) and of alkylarylsulfonic acids (alkyl radical: C9 to C ).

[0067] Further suitable emulsifiers are compounds of the general formula wherein R5 and R6 are hydrogen or C4- to C14-alkyl and are not simultaneously hydrogen, and X and Y may be alkali metal ions and / or ammonium ions. R5 and R6 are preferably linear or branched alkyl radicals having 6 to 18 carbon atoms or hydrogen and in particular having 6, 12 and 16 carbon atoms, wherein R5 and R6 are not both simultaneously hydrogen. X and Y are preferably sodium, potassium or ammonium ions, wherein sodium is particularly preferred. Compounds in which X and Y are sodium, R5 is a branched alkyl radical having 12 carbon atoms and R6 is hydrogen or R5 are particularly advantageous. Often employed are industrial mixtures comprising a proportion of 50% to 90% by weight of the monoalkylated product. Commercially available products of suitable emulsifiers are for example Dowfax® 2 A1 , Emulan® NP 50, Dextrol®OC 50, Emulgator 825, Emulgator 825 S, Emulan® OG, Texapon® NSC, Nekanil® 904 S, Lumiten® l-RA, Lumiten® E 3065, Disponil® FES 77, Lutensol® AT 18, Steinapol® VSL, Emulphor® NPS 25. Ionic emulsifiers or protective colloids are preferred for the present invention. Particular preference is given to ionic emulsifiers, in particular salts and acids, such as carboxylic acids, sulfonic acids and sulfates, sulfonates or carboxylates. Also employable in particular are mixtures of ionic and nonionic emulsifiers.

[0068] The emulsion polymerization may be initiated using water-soluble initiators. Water-soluble initiators are for example ammonium salts and alkali metal salts of peroxodisulfuric acid, for example sodium peroxodisulfate, hydrogen peroxide or organic peroxides, for example tert-butyl hydroperoxide. Also suitable as initiators are so-called reduction-oxidation (redox) initiator systems. Redox initiator systems consist of at least one generally inorganic reducing agent and an inorganic or organic oxidizing agent. The oxidant component is for example the emulsion polymerization initiators previously recited hereinabove. The reductant components are for example alkali metal salts of sulfurous acid, such as for example sodium sulfite, sodium hydrogensulfite, alkali metal salts of disulfurous acid such as sodium disulfite, bisulfite addition compounds of aliphatic aldehydes and ketones, such as acetone bisulfite or reducing agents such as hydroxymethanesulfinic acid and the salts thereof, or ascorbic acid. The redox initiator systems may be employed with co-use of soluble metal compounds whose metallic component may appear in a plurality of valence states. Typical redox initiator systems are, for example, ascorbic acidZiron(ll) sulfate / sodium peroxydisulfate, tert-butyl hydroperoxide / sodium disulfite, tert-butyl hydroperoxide / sodium hydroxymethanesulfinic acid. The individual components, for example the reductant component, may also be mixtures, for example a mixture of the sodium salt of hydroxymethanesulfinic acid and sodium disulfite.

[0069] The recited initiators are generally employed in the form of aqueous solutions, the lower concentration limit being determined by the amount of water acceptable in the dispersion and the upper concentration limit being determined by the solubility in water of the particular compound. The concentration of the initiators is generally 0.1% to 30% by weight, preferably 0.3% to 20% by weight, particularly preferably 0.5% to 10% by weight, based on the monomers to be polymerized. It is also possible to use two or more different initiators in the emulsion polymerization.

[0070] The emulsion polymerization is preferably carried out at 30°C to 130°C, preferably at 50°C to 90°C. The polymerization medium may consist either only of water or of mixtures of water and liquids miscible therewith such as methanol. Preference is given to using solely water. The emulsion polymerization may be carried out in the form of a feed process, including staged or gradient process modes. In the polymerization a polymer seed may be initially charged for more effective adjustment of particle size.

[0071] The manner in which the initiator is added to the polymerization vessel over the course of the free-radical aqueous emulsion polymerization is known to those of ordinary skill in the art. It may be either initially charged to the polymerization vessel in its entirety or employed continuously or in a staged manner at the rate of its consumption over the course of the free-radical aqueous emulsion polymerization. This specifically depends on the chemical nature of the initiator system and on the polymerization temperature. Preference is given to initially charging a portion and supplying the remainder to the polymerization zone at the rate of its consumption. In order to remove the residual monomers, it is common after the end of the emulsion polymerization proper, i.e., after a monomer conversion of at least 95%, to add initiator as well. In the feed process, the individual components may be added to the reactor from above, from the side or from below through the reactor floor.

[0072] The emulsion polymerization generally affords aqueous dispersions of the polymer having solids contents of from 15% to 75% by weight, preferably from 40% to 60% by weight, particularly preferably not less than 50% by weight.

[0073] The polymer thus produced is preferably used in the form of its aqueous dispersion. The size distribution of the dispersion particles may be monomodal, bimodal or polymodal and is preferably monomodal. The average particle diameter of the polymer particles dispersed in the aqueous dispersion is preferably greater than 200 nm, preferably greater than 250 nm, for example from 200 nm to 400 nm or from 250 nm to 350 nm. Average particle diameters XPCS and particle size distribution are measured by photon correlation spectroscopy (ISO standard 13321 :1996). The size distribution of the dispersion particles is monomodal when measurement of the particle size distribution contains only one single maximum.

[0074] The two-component lamination adhesive comprises in the first component at least one second polymer which is an adhesive polymer selected from polyurethanes. Suitable polyurethane dispersions are in principle obtainable by reaction of at least one polyisocyanate with at least one compound having at least two isocyanate-reactive groups and dispersion in water. Suitable polyurethanes also include so-called polyurethane-polyureas comprising not only polyurethane groups but also urea groups. The polyurethane dispersion preferably comprises at least one polyurethane which comprises at least one polyisocyanate and at least one polymeric polyol in copolymerized form. The polyurethane may in particular be formed from at least one polyisocyanate and at least one polymeric polyol. Suitable polymeric polyols are preferably selected from polyester diols, polyether diols, polycarbonate diols and mixtures thereof. The polymeric polyol preferably has a number-average molecular weight in the range from about 500 to 5000 g / mol. The molecular weight of the polymeric polyols can be determined from their OH-number which can be measured according to DIN 53 240. Polymeric diols are preferred. The polyurethane dispersion preferably comprises at least one polyurethane which comprises at least one polyisocyanate and a diol component in copolymerized form, of which a) 10-100 mol% based on the total amount of the diols have a molecular weight of 500 to 5000 g / mol and b) 0-90 mol% based on the total amount of the diols have a molecular weight of 60 to 500 g / mol.

[0075] The polyurethane is preferably constructed to an extent of at least 40% by weight, particularly preferably to an extent of at least 60% by weight and very particularly preferably to an extent of at least 80% by weight, based on the total weight of the monomers used for producing the polyurethane, from at least one diisocyanate and at least one polyether diol and / or polyester diol. Suitable further synthesis components to 100% by weight include for example the polyisocyanates recited below having at least three NCO groups and compounds distinct from the polymeric polyols having at least two isocyanate-reactive groups. These include for example diols; diamines; polymers distinct from polymeric polyols having at least two active hydrogen atoms per molecule; compounds having two active hydrogen atoms and at least one ionogenic / ionic group per molecule; and mixtures thereof.

[0076] Preferred polyurethanes are constructed from: a) at least one monomeric diisocyanate, b) at least one diol, of which b1) 10 to 100 mol%, based on the total amount of the diols (b), have a molecular weight of 500 to 5000 g / mol and b2) 0 to 90 mol%, based on the total amount of the diols (b), have a molecular weight of 60 to 500 g / mol, c) at least one monomer distinct from the monomers (a) and (b) having at least one isocyanate group or at least one isocyanate-reactive group which further bears at least one hydrophilic group or a potentially hydrophilic group, d) optionally at least one further compound distinct from the monomers (a) to (c) having at least two reactive groups selected from alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups, and e) optionally at least one monofunctional compound distinct from the monomers (a) to (d) having a reactive group which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group. It is particularly preferable when the ratio of the diols bi) to the diols b2) is 0.1 :1 to 5:1, particularly preferably 0.2:1 to 2:1. The diol b) is in particular selected from polytetrahydrofuran, polypropylene oxide and polyesterdiols selected from reaction products of dihydric alcohols with dibasic carboxylic acids and lactone-based polyesterdiols.

[0077] Compounds suitable as monomers (a) include in particular diisocyanates X(NCO)2, wherein X is an acyclic aliphatic hydrocarbon radical having 4 to 15 carbon atoms, a cycloaliphatic or aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 7 to 15 carbon atoms. Examples of such diisocyanates are tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4- diisocyanatocyclohexane, 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane (IPDI), 2,2-bis(4- isocyanatocyclohexyl)propane, trimethylhexane diisocyanate, 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, p-xylylene diisocyanate, tetramethylxylylene diisocyanate (TMXDI), the isomers of bis(4-isocyanatocyclohexyl)methane (HMDI), such as the trans / trans, the cis / cis and the cis / trans isomers, and mixtures composed of these compounds.

[0078] Such diisocyanates are commercially available. Mixtures of these isocyanates of particular importance are the mixtures of the respective structural isomers of diisocyanatotoluene and diisocyanatodiphenylmethane, the mixture of 80 mol% of 2,4-diisocyanatotoluene and 20 mol% of 2,6-diisocyanatotoluene being particularly suitable and preferred. In addition, the mixtures of aromatic isocyanates such as 2,4-diisocyanatotoluene and / or 2,6- diisocyanatotoluene with aliphatic or cycloaliphatic isocyanates, such as hexamethylene diisocyanate or IPDI, are particularly advantageous, the preferred quantitative ratio of the aliphatic isocyanates to aromatic isocyanates being 1 :9 to 9:1, in particular 4:1 to 1 :4.

[0079] The diols (b1) may be polyester polyols and these are known for example from Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, volume 19, pp. 62 to 65. Preference is given to using polyester polyols obtained by reaction of dihydric alcohols with dibasic carboxylic acids. Instead of using the free polycarboxylic acids, the polyester polyols may also be produced using the corresponding polycarboxylic anhydrides or corresponding polycarboxylic esters of lower alcohols or mixtures thereof. The polycarboxylic acids may be aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic and may optionally be substituted, for example by halogen atoms, and / or unsaturated. Examples thereof include: suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylene tetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimeric fatty acids. Preference is given to dicarboxylic acids of the general formula HOOC-(CH2)y-COOH, wherein y is a number from 1 to 20, preferably an even number from 2 to 20, for example succinic acid, adipic acid, sebacic acid and dodecane dicarboxylic acid. Suitable dihydric alcohols are, for example, ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1, 3-diol, butene-1,4-diol, butyne-1,4- diol, pentane-1,5-diol, neopentyl glycol, bis(hydroxymethyl)cyclohexanes such as 1,4- bis(hydroxymethyl)cyclohexane, 2-methylpropane-1, 3-diol, methylpentanediols, furthermore diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycols. Preferred alcohols are those of the general formula HO-(CH2)X-OH, wherein x is a number from 1 to 20, preferably an even number from 2 to 20. Examples thereof are ethylene glycol, butane-1 ,4-diol, hexane- 1 ,6-diol, octane-1, 8-diol and dodecane-1 ,12-diol. Neopentyl glycol is also preferred.

[0080] The diols (b1) may also be polycarbonate diols such as are obtainable for example by reaction of phosgene with an excess of the low molecular weight alcohols recited as synthesis components for the polyester polyols.

[0081] The diols (b1) may also be lactone-based polyester diols, specifically homopolymers or copolymers of lactones, preferably terminal hydroxyl-comprising addition products of lactones onto suitable difunctional starter molecules. Contemplated lactones preferably include those derived from compounds of the general formula HO-(CH2)Z-COOH, wherein z is a number from 1 to 20 and one hydrogen atom of a methylene unit may also be substituted by a Ci- to C4-alkyl radical. Examples include epsilon-caprolactone, beta-propiolactone, gamma-butyrolactone and / or methyl- gamma-caprolactone and mixtures thereof. Suitable starter components are, for example, the low-molecular weight- dihydric alcohols recited hereinabove as synthesis components for the polyester polyols. The corresponding polymers of epsilon-caprolactone are particularly preferred. Lower polyester diols or polyether diols may also be employed as starters for producing the lactone polymers. Instead of the polymers of lactones, the corresponding, chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones may also be employed.

[0082] The diols (b1) may also be polyether diols. Polyether diols are obtainable in particular by homopolymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin, for example in the presence of BF3, or by addition of these compounds optionally in admixture or in succession onto starting components having reactive hydrogen atoms, such as alcohols or amines, for example water, ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, 2,2-bis(4-hydroxyphenyl)propane or aniline. Polyether diols having a molecular weight of 500 to 5000 and especially 600 to 4500 are particularly preferred. Particularly preferred polyether diols are polypropylene oxide and polytetrahydrofuran. Suitable polytetrahydrofurans may be produced by cationic polymerization of tetrahydrofuran in the presence of acidic catalysts, such as for example sulfuric acid or fluorosulfuric acid. Such methods of production are known to those skilled in the art. Suitable compounds b1) further include alpha, omega-diaminopolyethers producible by amination of polyalkylene oxides with ammonia. bi) only includes polyether diols formed to an extent of less than 20% by weight, based on their total weight, of ethylene oxide. Polyether diols comprising at least 20% by weight of incorporated ethylene oxide units are hydrophilic polyether diols that are included among the monomers c).

[0083] Optionally co-usable as monomers bi) are also polyhydroxyolefins, preferably those having 2 terminal hydroxyl groups, for example alpha-omega-dihydroxypolybutadiene, alpha-omega-dihydroxypolymethacrylate esters or alpha- omega-dihydroxypolyacrylate esters as monomers. Such compounds are disclosed in EP-A 622 378 for example. Further suitable polyols are polyacetals, polysiloxanes and alkyd resins. It is preferable that at least 95 mol% of the diols bi) are polyether diols, in particular polypropylene glycol.

[0084] The hardness and the modulus of elasticity of the polyurethanes can be increased when as diols (b) not only the diols bi) but also low-molecular-weight diols b2) having a molecular weight of about 60 to 500, preferably of 62 to 200 g / ml, are employed. Employed monomers b2) especially include the synthesis components of the short-chain alkanediols recited for the production of polyester polyols, wherein the unbranched diols having 2 to 12 carbon atoms and an even number of carbon atoms and also pentane-1 ,5-diol and neopentyl glycol are preferred. Contemplated diols b2) include for example ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1 , 3-diol, butene-1 ,4-diol, butyne-1 ,4-diol, pentane-1, 5-diol, neopentyl glycol, bis(hydroxymethyl)cyclohexanes such as 1,4- bis(hydroxymethyl)cyclohexane, 2-methylpropane-1, 3-diol, methylpentanediols, furthermore diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycols. Preferred alcohols are those of the general formula HO-(CH2)X-OH, wherein x is a number from 1 to 20, preferably an even number from 2 to 20. Examples thereof are ethylene glycol, butane-1, 4-diol, hexane- 1 ,6-diol, octane-1, 8-diol and dodecane-1 ,12-diol. Neopentyl glycol is also preferred.

[0085] In order to ensure that the polyurethanes are water-dispersible, the polyurethanes comprise as a synthesis component monomers (c) which are distinct from the components (a) and (b) and bear at least one isocyanate group or at least one isocyanate-reactive group and moreover bear at least one hydrophilic group or a group which can be converted into a hydrophilic group. Hereinbelow, the term "hydrophilic groups or potentially hydrophilic groups" is abbreviated to "(potentially) hydrophilic groups". The (potentially) hydrophilic groups react with isocyanates substantially more slowly than the functional groups of the monomers used to construct the polymer main chain. The proportion of components comprising (potentially) hydrophilic groups in the total amount of components (a) to (f) is generally measured such that the molar amount of the (potentially) hydrophilic groups (preferably anionic or potentially anionic groups) based on the amount by weight of all monomers (a) to (e) is 30 to 1000, preferably 50 to 500 and particularly preferably 80 to 300 mmol / kg. The (potentially) hydrophilic groups may be nonionic or preferably (potentially) ionic hydrophilic groups.

[0086] Contemplated nonionic hydrophilic groups include in particular polyethylene glycol ethers composed of preferably 5 to 100, preferably 10 to 80, ethylene oxide repeating units. The content of polyethylene oxide units is generally 0% to 10% by weight, preferably 0% to 6% by weight, based on the amount by weight of all monomers (a) to (e). Preferred monomers comprising nonionic hydrophilic groups are polyethylene oxide diols comprising at least 20% by weight of ethylene oxide, polyethylene oxide monools and the reaction products of a polyethylene glycol and a diisocyanate which bear a terminally etherified polyethylene glycol radical. Such diisocyanates and processes for their production are recited in patent documents US-A 3,905,929 and US-A 3,920,598.

[0087] Ionic hydrophilic groups are especially anionic groups, such as the sulfonate, carboxylate and the phosphate group in the form of their alkali metal or ammonium salts, and cationic groups, such as ammonium groups, in particular protonated tertiary amino groups or quaternary ammonium groups. Potentially ionic hydrophilic groups are especially those which may be converted into the abovementioned ionic hydrophilic groups by simple neutralization, hydrolysis or quaternization reactions, i.e. carboxylic acid groups or tertiary amino groups for example. (Potentially) ionic monomers (c) are described in detail for example in Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, volume 19, pp. 311-313 and for example in DE-A 1 495745.

[0088] (Potentially) cationic monomers (c) of particular practical importance are especially monomers comprising tertiary amino groups, for example: tris(hydroxyalkyl)amines, N,N'-bis(hydroxyalkyl)alkylamines, N-hydroxyalkyl dialkylamines, tris(aminoalkyl)amines, N, N'-bis(aminoalkyl)alkylamines, N-aminoalkyl dialkylamines, wherein the alkyl radicals and alkanediyl units of these tertiary amines are independently of one another composed of 1 to 6 carbon atoms. Also contemplated are polyethers comprising tertiary nitrogen atoms and preferably two terminal hydroxyl groups, such as are obtainable in a manner customary per se for example by alkoxylation of amines comprising two hydrogen atoms attached to amine nitrogen, for example methylamine, aniline or N,N'- dimethylhydrazine. Such polyethers generally have a molar weight of between 500 and 6000 g / mol. These tertiary amines are converted into the ammonium salts either with acids, preferably strong mineral acids such as phosphoric acid, sulfuric acid, hydrohalic acids, or strong organic acids or by conversion with suitable quaternization agents such as Ci- to Ce-alky I halides or benzyl halides, for example bromides or chlorides.

[0089] Contemplated monomers comprising (potentially) anionic groups typically include aliphatic, cycloaliphatic, araliphatic or aromatic carboxylic acids and sulfonic acids bearing at least one alcoholic hydroxyl group or at least one primary or secondary amino group. Preference is given to dihydroxyalkylcarboxylic acids, especially comprising 3 to 10 carbon atoms, as also described in US 3,412,054. Preferred compounds include in particular compounds of the general formula (ci) in which R1and R2represent a Ci- to C4-alkanediyl (unit) and R3represents a Ci- to C4-alkyl (unit), especially dimethylolpropionic acid (DMPA). Corresponding dihydroxysulfonic acids and dihydroxyphosphonic acids such as 2,3-dihydroxypropanephosphonic acid are also suitable. Also suitable are dihydroxy compounds having a molecular weight of more than 500 to 10 000 g / mol and comprising at least 2 carboxylate groups, as disclosed in DE-A 39 11 827. These are obtainable by reacting dihydroxy compounds with tetracarboxylic dianhydrides, such as pyromellitic dianhydride or cyclopentanetetracarboxylic dianhydride in a molar ratio of 2:1 to 1.05:1 in a polyaddition reaction. Suitable dihydroxy compounds are in particular the monomers (b2) cited as chain extenders and the diols (b1).

[0090] Contemplated monomers (c) comprising isocyanate-reactive amino groups also include aminocarboxylic acids such as lysine, beta-alanine or the adducts, cited in DE-A 20 34479, of aliphatic diprimary diamines onto alpha, betaunsaturated carboxylic or sulfonic acids. Such compounds for example conform to the formula (C2) H2N-R4-NH-R5-X (C2) in which R4and R5independently of one another represent a Ci- to Ce-alkanediy I unit, preferably ethylene; and X represents COOH or SO3H. Particularly preferred compounds of formula (c2) are N-(2-aminoethyl)-2- aminoethanecarboxylic acid and N-(2-aminoethyl)-2-aminoethanesulfonic acid and the corresponding alkali metal salts, wherein sodium is a particularly preferred counterion. Also particularly preferred are the adducts of the abovementioned aliphatic diprimary diamines onto 2-acrylamido-2-methylpropanesulfonic acid, as described for example in DE-B 1 954090.

[0091] Where monomers containing potentially ionic groups are employed, their conversion into the ionic form may take place before, during, but preferably after the isocyanate polyaddition, since the solubility of the ionic monomers in the reaction mixture is frequently no more than poor. Neutralizing agents are for example ammonia, NaOH, triethanolamine (TEA), triisopropylamine (TIPA) or morpholine, and derivatives thereof. The sulfonate or carboxylate groups are especially preferably present in the form of their salts with an alkali metal ion or with an ammonium ion as the counterion.

[0092] The monomers (d) which are distinct from the monomers (a) to (c), and which are optionally also constituents of the polyurethane are generally used for crosslinking or chain extension. They are generally more than dihydric nonphenolic alcohols, amines comprising 2 or more primary and / or secondary amino groups and compounds bearing one or more primary and / or secondary amino groups in addition to one or more alcoholic hydroxyl groups. Alcohols having a hydricity greater than 2 and which may be used to establish a certain degree of branching or crosslinking are, for example, trimethylolpropane, glycerol and sugar.

[0093] Also contemplated are monoalcohols which carry not only the hydroxyl group but also a further isocyanate-reactive group such as monoalcohols having one or more primary and / or secondary amino groups, for example monoethanolamine. Polyamines having 2 or more primary and / or secondary amino groups are primarily used when the chain extension and / or crosslinking is to take place in the presence of water since amines generally react with isocyanates more rapidly than alcohols or water. This is often necessary when aqueous dispersions of crosslinked polyurethanes or polyurethanes of high molecular weight are desired. The procedure in such cases comprises producing prepolymers comprising isocyanate groups, rapidly dispersing said prepolymers in water and subsequently chain-extending or crosslinking said prepolymers by adding compounds comprising a plurality of isocyanate-reactive amino groups.

[0094] Amines suitable for this purpose are generally polyfunctional amines in the molecular weight range from 32 to 500 g / mol, preferably from 60 to 300 g / mol, which comprise at least two amino groups selected from the group of the primary and secondary amino groups. Examples thereof are diamines such as diaminoethane, diaminopropanes, diaminobutanes, diaminohexanes, piperazine, 2,5-dimethylpiperazine, amino-3-aminomethyl-3,5,5- trimethylcyclohexane (isophoronediamine, IPDA), 4,4'-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, aminoethyl ethanolamine, hydrazine, hydrazine hydrate or triamines such as diethylenetriamine or 1 ,8-diamino-4- aminomethyloctane. The amines may also be employed in blocked form, for example in the form of the corresponding ketimines (see, for example, CA-A 1 129 128), ketazines (cf. , for example, US-A 4,269,748) or amine salts (see US-A 4,292,226). Oxazolidines, as are used, for example, in US-A 4,192,937, also represent capped polyamines which can be used for producing the polyurethanes according to the invention for chain extension of the prepolymers. Use of such capped polyamines generally comprises mixing said polyamines with the prepolymers in the absence of water and subsequently mixing this mixture with the dispersion water or a portion of the dispersion water, thus releasing the corresponding polyamines hydrolytically. It is preferable to use mixtures of di- and triamines, particularly preferably mixtures of isophorone diamine (IPDA) and diethylene triamine (DETA).

[0095] The polyurethanes preferably comprise 1 to 30 mol%, particularly preferably 4 to 25 mol%, based on the total amount of the components (b) and (d) of a polyamine comprising at least 2 isocyanate-reactive amino groups as monomers (d). Higher than difunctional isocyanates may also be used as monomers (d) for the same purpose. Commercially available compounds are, for example, the isocyanurate or the biuret of hexamethylene diisocyanate.

[0096] Monomers (e) that are optionally co-used are monoisocyanates, monoalcohols and monoprimary and -secondary amines. The proportion thereof is generally not more than 10 mol%, based on the total molar amount of the monomers. These monofunctional compounds typically bear further functional groups such as olefinic groups or carbonyl groups and serve to introduce functional groups into the polyurethane which make the dispersal or crosslinking or further polymer-analogous reaction of the polyurethane possible. Contemplated therefor are monomers such as isopropenyl-a,a’-dimethylbenzyl isocyanate (TMI) and esters of acrylic or methacrylic acid such as hydroxyethyl acrylate or hydroxyethyl methacrylate.

[0097] Preferred are polyurethanes, wherein the diisocyanates a) are selected from diisocyanates of the formula X(NCO)2, wherein X represents an acyclic aliphatic hydrocarbon radical having 4 to 15 carbon atoms, a cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms, an aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 7 to 15 carbon atoms, preferably selected from the group consisting of hexamethylene diisocyanate, 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, 2,6- diisocyanatotoluene, 2,4-diisocyanatotoluene and tetramethylxylylene diisocyanate or a mixture thereof; the diols b1) are selected from polyester diols, polycarbonate diols and polyether diols; and the compound c) is selected from dihydroxycarboxylic acids, diaminocarboxylic acids and diaminosulfonic acids.

[0098] The way in which the molecular weight of the polyurethanes may be adjusted through choice of the proportions of the mutually reactive monomers and of the arithmetic mean of the number of reactive functional groups per molecule is common general knowledge in the field of polyurethane chemistry. The components (a) to (e) and their respective molar amounts are normally chosen such that the ratio A : B where

[0099] A is the molar amount of isocyanate groups and B is the sum of the molar amount of hydroxyl groups and the molar amount of functional groups which are capable of reacting with isocyanates in an addition reaction, is

[0100] 0.5:1 to 2:1, preferably 0.8:1 to 1.5:1, particularly preferably 0.9:1 to 1.2:1. It is very particularly preferable when the ratio A: B is very close to 1 : 1 .

[0101] The monomers (a) to (e) employed bear on average typically from 1.5 to 2.5, preferably from 1.9 to 2.1 and particularly preferably 2.0 isocyanate groups or functional groups capable of reacting with isocyanates in an addition reaction.

[0102] The polyurethane is preferably characterized by being amorphous, non-crystalline. The polyurethane preferably has a K-value between 20 to 80. The K value is a relative viscosity number which is determined in analogy to DIN 53726 at 25°. It comprises the flow rate of a 1% strength by weight solution of polyurethane in DMF relatively to the flow rate of pure DMF and characterizes the average molecular weight of the polyurethane.

[0103] The polyurethane preferably has a glass transition temperature of minus 60 °C to minus 10 °C, measured by differential scanning calorimetry at a heating rate of 20°C / min.

[0104] The polyaddition of the components (a) to (e) to produce the polyurethane is preferably carried out at reaction temperatures of up to 180°C, preferably up to 150°C, under standard pressure or under autogenous pressure. The production of polyurethanes and of aqueous polyurethane dispersions is known to those skilled in the art.

[0105] In the context of the present invention an aqueous polyurethane dispersion is to be understood as meaning a dispersion which has an aqueous solvent as the continuous phase. Suitable aqueous solvents are water and mixtures of water with water-miscible solvents, for example alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-hexanol and cyclohexanol; glycols, such as ethylene glycol, propylene glycol and butylene glycol; the methyl or ethyl ethers of dihydric alcohols, diethylene glycol, triethylene glycol, polyethylene glycols having number-average molecular weights up to about 3000, glycerol and dioxane, and ketones, such as acetone in particular. In one specific embodiment the polyurethane dispersion is substantially free from organic solvents. "Substantially free from organic solvents” is to be understood as meaning that the proportion of organic solvents is not more than 5% by weight, particularly preferably not more than 1% by weight, in particular not more than 0.1% by weight, based on the total weight of the solvent.

[0106] In a preferred embodiment the production of the polyurethanes is carried out in the presence of at least one organic solvent. Preferred organic solvents for production of the polyurethanes are ketones, such as acetone and methyl ethyl ketone, and N-methylpyrrolidone. Particular preference is given to using acetone. If an at least partially water- miscible solvent is used to produce the polyurethanes, the polyurethane dispersion according to the invention may contain not only water but also the organic solvent used for production. It will be appreciated that the production of the polyurethane dispersions according to the invention may be carried out in the presence of at least one organic solvent, with said solvent subsequently being partially or completely replaced with water.

[0107] The pH of the component of the lamination adhesive which is in the form of an aqueous polymer dispersion, is preferably adjusted to a pH greater than 5, in particular to a pH between 5.5 and 8.

[0108] The aqueous polymer dispersions may be employed as such or after formulating with customary further auxiliaries (additives). Typical auxiliaries are, for example, defoamers, preservatives, UV stabilizers, catalysts, drying agents, antistatic agents, flame retardants, thickeners (preferably associative thickeners), thixotropic agents, surface-active agents, viscosity modifiers, plasticizers, levelling agents, tackifiers, wetting agents or chelating agents. For better wetting of surfaces the polymer dispersions may include in particular wetting agents, for example fatty alcohol ethoxylates, alkylphenol ethoxylates, nonylphenol ethoxylates or sodium dodecyl sulfonates. The amount of further auxiliaries is preferably 0.05% to 5% by weight, especially 0.25% to 3% by weight, based on the total weight of the aqueous polymer dispersion.

[0109] The first component of the two-component lamination adhesive is an aqueous composition preferably comprising

[0110] (i) from 25% to 70% by weight of the at least one first polymer;

[0111] (ii) from 25% to 70% by weight of the at least one second polymer;

[0112] (iii) from 0.25% to 5% by weight of one or more additives, preferably selected from the group consisting of defoamers, preservatives, UV stabilizers, catalysts, drying agents, antistatic agents, flame retardants, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, plasticizers levelling agents, tackifiers, wetting agents or chelating agents.

[0113] For sustainability reasons it is preferred to use bio-based materials for producing the at least one first polymer and / or the at least one second polymer. The term "bio-based” indicates that the material is of biological origin and comes from a biomaterial / renewable resource. A material of renewable origin or biomaterial is an organic material wherein the carbon comes from the CO2 fixed recently (on a human scale) by photosynthesis from the atmosphere. A biomaterial (carbon of 100% natural origin) has an isotopic ratio14C / 12C greater than 10-12, typically about 1 .2x10-12, while a fossil material has a zero ratio. Indeed, the isotopic14C is formed in the atmosphere and is then integrated via photosynthesis, according to a time scale of a few tens of years at most. The half-life of the14C is 5,730 years. Thus, the materials coming from photosynthesis, namely plants in general, necessarily have a maximum content in isotope14C. The determination of the content of biomaterial or of bio-carbon can be carried out in accordance with the standards ASTM D 6866-12, the method B (ASTM D 6866-06) and ASTM D 7026 (ASTM D 7026-04). The polymers of the first component of the two-component lamination adhesive preferably consists to an extent of at least 5 weight%, more preferably at least 10 weight% of bio-based materials, based on the sum total of all polymers of the first and second polymers. Suitable bio-based materials for producing the first polymer by emulsion polymerization are for example (meth)acrylic esters, wherein the (meth)acrylic acid component or the alcohol component or both are bio-based. Various methods of producing bio-based acrylic acid from renewable plant materials are mentioned in EP 2626397 A1. Suitable biobased alcohols are for example bio-based iso-butanol, bio-based n-butanol, bio-based ethanol, bio-based isopentanol (3-methylbutan-1-ol), bio-based 2-octanol, bio-based 1-octanol and bio-based n-heptanol. Preferred partly biobased monomers are esters of (meth)acrylic acid and bio-based alcohols, preferably bio-based 2-octanol, biobased 1-octanol, bio-based ethanol, bio-based iso-butanol, bio-based n-butanol, bio-based iso-pentanol (3- methylbutan-1 -ol), bio-based and bio-based n-heptanol. Preferred fully biobased monomers are esters of bio-based acrylic acid and bio-based alcohols as mentioned above. Preferably at least the carbon atoms of the alkyl group of at least one of the monomers 2-octyl acrylate, 1 -octyl acrylate, isobutyl acrylate and ethyl acrylate is of biological origin. Preferably, at least 50 wt.%, more preferred 100 wt.% of 2-octyl acrylate monomer is made from bio-based 2-octanol and non-bio-based or bio-based acrylic acid, i.e. preferably at least the carbon atoms of the 2-octyl group of 2-octyl acrylate are of biological origin. Preferably, monomers comprise iso butyl acrylate wherein at least the carbon atoms of the iso butyl group are of biological origin.

[0114] Suitable bio-based materials for producing polyurethanes are for example alcohols (in particular diols and polyols) and organic acids (in particular diacids) derived from natural materials such as starch, saccharose, glucose, lignocellulose, natural rubber or plant oils. Suitable alcohols and organic acids derived from natural materials are for example ethanol, monoethylene glycol, polyethylene glycol, isosorbide, 1 ,3-propanediol, 1 ,4-butanediol, glycerol, adipic acid or succinic acid. Preferably at least part of the polyurethane is made of bio-based materials.

[0115] For sustainability reasons it is preferred to use recycled raw materials for producing the at least one first polymer and / or the at least one second polymer. Polyurethanes can be found in many products, for example, in soft foams (mattresses, sponges, upholstered furniture), hard foams (insulation materials, building materials), thermoplastics (sports shoes), coatings (varnishes, paints) or adhesives. There is a need for sustainable recycling of polyurethane waste, which allows the building blocks of polyurethane polymers to be reused. To do this, the bonds in the polyurethanes are split in order to be able to obtain defined degradation products and thus make them recyclable and reusable in the production of new polyurethanes. The polyurethane adhesive preferably consists to an extent of at least 5 weight%, more preferably at least 10 weight% of recycled materials, based on the sum total of all polyurethane adhesive synthesis components. One method of recycling of polyurethanes is thermal recycling. This process takes place at high temperatures, as well as with the use of catalysts to recover monomers or building blocks. For example, thermal glycolysis, which is currently the most common chemolysis for recycling of polyurethanes has already been implemented industrially. It allows the recovery of polyols. DE 102004014165 describes a method for the production of polyols from waste polyurethane by reacting a mixture of waste polyurethane, glycols or oligo-ester mixture (from polyester production) and primary and / or secondary aliphatic amines. EP 0733669 A2 describes a method for the utilization of plastic waste containing mixtures of polyurethanes and other plastics, comprising (a) reacting the waste with a mixture of low-molecular weight, at least difunctional alcohols (I) and polyether-polyol(s) (II), and (b) separating the polyol glycolysis products from the rest of the waste by mechanical methods. The glycolysis polyols obtained by this process can be used to manufacture new polyurethanes. Low-amine glycolysis products from polyurethane waste is preferably used as the recycled polyol. For economic reasons, preferably at least 5% by weight, more preferably at least 10% by weight, of recycled polyol, based on the total amount of isocyanate-reactive compounds are used for producing new polyurethanes.

[0116] The recycled polyols can be obtained by glycolysis of polyurethane waste with short-chain, hydroxyl-containing compounds, such as for example ethylene oxide-propylene oxide copolymers, OH-functionalized polybutadienes), ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, oligoethylene glycols, propylene glycol, dipropylene glycol, tripropylene glycol, oligopropylene glycols, ethylene oxide-propylene oxide copolymers, butanediol, OH-functionalized polybutadienes, neopentyl glycol, glycerol, diethanolamine and triethanolamine, optionally obtained in the presence of organometallic catalysts at higher temperatures. Non-enzymatic hydrolysis at high temperature and high pressures allows recovery of both polyols and amines as re-usable products.

[0117] Another method is enzymatic degradation of polyurethanes into defined monomers which can be reused for production of new polyurethanes, for example by urethanases as described in WO 2019 / 243293. The recycled raw materials from enzymatic degradation for producing new polyurethanes preferably are low molecular weight degradation products, preferably of polyester-based polyurethanes, preferably with a molecular weight of at most 1,000 g / mol.

[0118] Suitable recycled raw materials are for example

[0119] (I) polyols and polycarboxylic acids which were used to synthesize the polyester polyols used for the synthesis of the polyurethane in question; and

[0120] (II) amines which are derived from the isocyanates used in the production of the polyurethane in question, for example in the case of 2,4-tolylene diisocyanate, 2,4-tolylene diamine.

[0121] A "polyol” is understood to mean any compound having at least two hydroxyl groups.

[0122] Said low molecular weight polyol preferably has a molecular weight of at most 300 g / mol. Preferred recycled low molecular weight polyols are selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1 ,2-di-propylene glycol, neopentyl glycol, glycerol, 1,1,1 -trimethylolpropane, sucrose, sorbitol and pentaerythritol.

[0123] A "polycarboxylic acid” is understood to mean any compound which contains at least two carboxyl groups. Said low molecular weight polycarboxylic acid preferably has a molecular weight of at most 300 g / mol. Preferred recycled low molecular weight polycarboxylic acids, are selected from the group consisting of succinic acid, glutaric acid, adipic acid, phthalic acid, terephthalic acid, benzene tricarboxylic acid, oleic acid and ricinoleic acid.

[0124] A "poly amine” is understood to mean any compound which contains at least two amino groups. Said low molecular weight polyamine preferably has a molecular weight of at most 300 g / mol. Preferred low molecular weight recycled polyamines, are selected from the group consisting of 4,4'-methylenediamine, 2,4'-methylenediamine, 2,2'- methylenediamine, 2,4-tolylenediamine, 2,6-tolylenediamine, hexamethylenediamine, isophoronediamine, xylylenediamine, pentamethylenediamine, para-phenylenediamine, butylenediamine and H12-methylenediamine.

[0125] The polyamines are particularly preferably selected from the group consisting of 4,4'-methylenediamine, 2,4'- methylenediamine, 2,2'-methylenediamine, 2,4-tolylenediamine and 2,6-tolylenediamine. In one aspect of the invention the two-component lamination adhesive comprises the first polymer, the second polymer or both which are at least partly made of bio based or recycled material.

[0126] The second component of the lamination adhesive comprises a crosslinking compound capable of crosslinking the first component, i.e. crosslinking at least one of the first and second polymers of the first component.

[0127] The weight amount ratio of the crosslinking compound to the first and second polymer is preferably from 1 to 5 parts by weight per 100 parts by weight of the sum of the polymers.

[0128] The crosslinking compound of the second component of the lamination adhesive is preferably at least one compound selected from the group consisting of polyisocyanates and polycarbodiimides.

[0129] Suitable crosslinking compounds are at least one, for example one to three, preferably one to two, and more preferably precisely one, polyisocyanate which is obtainable by reacting at least one monomeric isocyanate. The monomeric isocyanates used to obtain the polyisocyanate may be aromatic, aliphatic or cycloaliphatic, preferably aliphatic or cycloaliphatic, which is referred to for short in this text as (cyclo)aliphatic; aliphatic isocyanates are particularly preferred. Aromatic isocyanates are those which comprise at least one aromatic ring system, i.e. both purely aromatic and araliphatic compounds. Cycloaliphatic isocyanates are those which comprise at least one cycloaliphatic ring system. Aliphatic isocyanates are those which comprise exclusively linear or branched chains, in other words acyclic compounds. The monomeric isocyanates are preferably diisocyanates bearing exactly two isocyanate groups.

[0130] In principle, higher isocyanates having an average of more than 2 isocyanate groups are also an option. Suitable examples of these include triisocyanates such as triisocyanatononane, 2'-isocy anatoethy I 2,6- diisocyanatohexanoate, 2,4,6-triisocyanatotoluene, triphenylmethane triisocyanate or 2,4,4'-triisocyanatodiphenyl ether, or the mixtures of diisocyanates, triisocyanates, and higher polyisocyanates that are obtained, for example, by phosgenating corresponding aniline / formaldehyde condensates and constitute polyphenyl polyisocyanates having methylene bridges. These monomeric isocyanates do not contain any substantial products of reaction of the isocyanate groups with themselves.

[0131] The monomeric isocyanates are preferably isocyanates having 4 to 20 C atoms. Examples of typical diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, pentamethylene 1 ,5-diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, derivatives of lysine diisocyanate, (e.g., methyl or ethyl 2, 6-diisocy- anatohexanoate), trimethylhexane diisocyanate or tetramethylhexane diisocyanate, cycloaliphatic diisocyanates such as 1,4-, 1,3- or 1,2-diisocyanatocyclohexane, 4,4'- or 2,4'-di(isocyanatocyclohexyl)methane, 1-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 also 3(or 4),8(or 9)- bis(isocyanatomethyl)tricyclo[5.2.1 ,026]decane isomer mixtures, and also 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, 1 -chloro-2,4-phenylene diisocyanate, 1 ,5-naphthylene diisocyanate, diphenylene 4,4'-di-isocyanate, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, 3-methyldiphenylmethane 4,4'-diisocyanate, tetramethylxylylene diisocyanate, 1,4-diisocyanatobenzene, or diphenyl ether 4,4'-diisocyanate. Particular preference is given to 1,6-hexamethylene diisocyanate, 1,3- bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, and 4,4'- or 2,4'-di-(isocyanatocyclohexyl)methane, very particular preference to isophorone diisocyanate and 1,6-hexamethylene diisocyanate, and especial preference to 1,6-hexamethylene diisocyanate. It is also possible for mixtures of the isocyanates mentioned to be present.

[0132] Isophorone diisocyanate is usually in the form of a mixture, specifically a mixture of the cis and trans isomers, generally in a proportion of about 60:40 to 80:20 (w / w), preferably in a proportion of about 70:30 to 75:25, and more preferably in a proportion of approximately 75:25. Dicyclohexylmethane 4,4'-diisocyanate may likewise be in the form of a mixture of the different cis and trans isomers.

[0133] The polyisocyanates which can be formed by oligomerizing the monomeric isocyanates, are generally characterized as follows: The average NCO functionality of such compounds is generally at least 1 .8 and may be up to 8, preferably 2 to 5, and more preferably 2.4 to 4. The content of isocyanate groups after oligomerization, calculated as NCO = 42 g / mol, is generally 5% to 25% by weight, unless indicated otherwise. Preferably, the polyisocyanates are the following compounds:

[0134] 1) Polyisocyanates which have isocyanurate groups and derive from aromatic, aliphatic and / or cycloaliphatic diisocyanates. Particular preference here is given to the corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanurates and in particular to those based on hexamethylene diisocyanate and isophorone diisocyanate. These present isocyanurates are, in particular, trisisocyanatoalkyl and / or trisisocy anatocycloalky I isocyanurates, which are cyclic trimers of the diisocyanates, or are mixtures with their higher homologs containing more than one isocyanurate ring. The isocyanatoisocyanurates generally have an NCO content of 10% to 30% by weight, in particular 15% to 25% by weight, and an average NCO functionality of 2.6 to 8.

[0135] 2) Polyisocyanates having uretdione groups, with aromatically, aliphatically and / or cycloaliphatically bonded isocyanate groups, preferably aliphatically and / or cycloaliphatically bonded, and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cyclic dimerization products of diisocyanates. The polyisocyanates having uretdione groups are obtained in the context of this invention in a mixture with other polyisocyanates, especially those mentioned under 1). To this end, the diisocyanates are converted under reaction conditions under which both uretdione groups and the other polyisocyanates are formed, or the uretdione groups are formed first and these are subsequently converted to the other polyisocyanates, or the diisocyanates are first converted to the other polyisocyanates and these are then converted to products containing uretdione groups. 3) Biuret group-containing polyisocyanates having aromatically, cycloaliphatically or aliphatically bonded, preferably cycloaliphatically or aliphatically bonded, isocyanate groups, especially tris(6-isocyanatohexyl)biuret or mixtures thereof with higher homologs thereof. These polyisocyanates having biuret groups preferably (particularly in the case of HDI) have an NCO content of 18% to 23.5% by weight and an average NCO functionality of 2.8 to 6.

[0136] 4) Urethane and / or allophanate group-containing polyisocyanates having aromatically, aliphatically or cycloaliphatically bonded, preferably aliphatically or cycloaliphatically bonded, isocyanate groups, as can be obtained, for example, by reaction of excess amounts of diisocyanate, for example hexamethylene diisocyanate or isophorone diisocyanate, with mono- or polyhydric alcohols (A). These polyisocyanates having urethane and / or allophanate groups generally have an NCO content of 12% to 24% by weight and an average NCO functionality of 2.3 to 4.5. Polyisocyanates of this kind containing urethane and / or allophanate groups may be prepared uncatalyzed or, preferably, in the presence of catalysts, such as ammonium carboxylates or ammonium hydroxides, for example, or allophanatization catalysts, such as Zn(ll) compounds, for example, in each case in the presence of monohydric, dihydric or polyhydric, preferably monohydric, alcohols.

[0137] 5) Polyisocyanates comprising oxadiazinetrione groups, derived preferably from hexamethylene diisocyanate or isophorone diisocyanate. Such polyisocyanates comprising oxadiazinetrione groups are obtainable from diisocyanate and carbon dioxide.

[0138] 6) Polyisocyanates comprising iminooxadiazinedione groups, derived preferably from hexamethylene diisocyanate or isophorone diisocyanate. Such polyisocyanates comprising iminooxadiazinedione groups are preparable from diisocyanates by means of specific catalysts. They are typically present in a mixture with polyisocyanates 1), optionally also with 2) and / or 4).

[0139] 7) Uretonimine-modified polyisocyanates.

[0140] 8) Carbodiimide-modified polyisocyanates.

[0141] 9) Hyperbranched polyisocyanates, as known for example from DE-A1 10013186 or DE-A1 10013187.

[0142] 10) Polyurethane-polyisocyanate prepolymers, from di- and / or polyisocyanates with alcohols.

[0143] 11 ) Polyurea-polyisocyanate prepolymers.

[0144] 12) The polyisocyanates 1)-11), preferably 1), 3), 4) and 6), after preparation thereof, can be converted to biuret group-containing or urethane / allophanate group-containing polyisocyanates having aromatically, cycloaliphatically or aliphatically bonded, preferably (cyclo)aliphatically bonded, isocyanate groups. Biuret groups are formed, for example, by addition of water or reaction with amines. Urethane and / or allophanate groups are formed by reaction with monohydric, dihydric or polyhydric, preferably monohydric, alcohols, optionally in the presence of suitable catalysts. These biurets or urethane / allophanate group-containing polyisocyanates generally have an NCO content of 18% to 22% by weight and an average NCO functionality of 2.8 to 6.

[0145] 13) Hydrophilically modified polyisocyanates, i.e. polyisocyanates which, as well as the groups described under 1- 12, comprise those which arise in a formal sense through addition of molecules having NCO-reactive groups and hydrophilizing groups onto the isocyanate groups of the above molecules. The latter groups are nonionic groups such as alkylpolyethylene oxide and / or ionic groups derived from phosphoric acid, phosphonic acid, sulfuric acid or sulfonic acid, and / or their salts, with organic modification. They may be used here, untypically but in accordance with the invention, in solventborne systems, more particularly as a co-component of the isocyanate component.

[0146] 14) Modified polyisocyanates for dual-cure applications, i.e. polyisocyanates which, as well as the groups described under 1-13, comprise those which arise in a formal sense through addition of molecules having NCO-reactive groups and groups crosslinkable by UV or actinic radiation onto the isocyanate groups of the above molecules. These molecules are, for example, hydroxyalkyl (meth)acrylates and other hydroxyl-vinyl compounds.

[0147] The diisocyanates or polyisocyanates listed above may also be at least partly in blocked form. Classes of compound used for blocking are described in D. A. Wicks, Z. W. Wicks, Progress in Organic Coatings, 36, 148-172 (1999), 41, 1-83 (2001) and 43, 131-140 (2001). Examples of classes of compound used for blocking are phenols, imidazoles, triazoles, pyrazoles, oximes, N-hydroxy imides, hydroxybenzoic esters, secondary amines, lactams, CH-acidic cyclic ketones, malonic esters or alkyl acetoacetates.

[0148] Preferred polyisocyanate crosslinking compounds are at least one polyisocyanate selected from the group consisting of isocyanurates, iminooxadiazinediones, biurets, uretdiones, urethanes, and allophanates; preferably from the group consisting of isocyanurates, urethanes and allophanates, more preferably from the group consisting of isocyanurates and allophanates, and it is especially a polyisocyanate containing isocyanurate groups. In one particularly preferred embodiment, the polyisocyanate comprises polyisocyanates which comprise isocyanurate groups and derive from 1,6-hexamethylene diisocyanate. In a further particularly preferred embodiment, the polyisocyanate is a mixture of polyisocyanates which comprise isocyanurate groups and derive from 1,6-hexamethylene diisocyanate and from isophorone diisocyanate.

[0149] Preferred polyisocyanate crosslinking compounds are obtainable by reacting at least one monomeric isocyanate, wherein the monomeric isocyanate is at least one monomeric isocyanate preferably selected from the group consisting of 1,6-hexamethylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, and 4,4'- or 2,4'-di(isocyanatocyclohexyl)methane, preferably 1,6-hexamethylene diisocyanate or isophorone diisocyanate.

[0150] Preferably, the polyisocyanate crosslinker has viscosity of 1000 to 4000 mPa s (at 23°C, DIN ISO 3219), shear D 1000 sec1. Preferably the polyisocyanate crosslinker has an NCO content (DIN EN ISO 11909) of 15 to 20%.

[0151] The invention provides a process of lamination, in which two substrates are bonded together wherein a) a first substrate in the form of a first film or paper is provided, b) a second substrate is provided, selected from paper and a second film that may be the same or different from the first film, c) the two-component adhesive as described herein is provided, and d) the two-component adhesive is applied onto the first substrate and / or onto the second substrate, optionally being allowed to dry, and the first substrate is laminated onto the second substrate.

[0152] In the process according to the invention the adhesive-coated articles may be selected, for example, from laminates, preferably in processes for bonding large-surface-area substrates. Said articles are preferably composite films or glossy films. In the case of composite films, at least two films are bonded to one another using the aqueous dispersion adhesive composition, wherein preferably one or both films are transparent. In the case of glossy films, a transparent film is laminated onto paper or card.

[0153] For applications in laminating processes the laminating adhesive is preferably non-self-adhesive. Non-self-adhesive adhesives are adhesives which, unlike pressure-sensitive adhesives, have only very little, if any, tack at room temperature and are preferably employed with application of pressure and / or elevated temperature. The tack measured as loop tack is preferably less than 1 .7 N / 25 mm (adhesive applied at an application thickness of 20 pm to a 12 pm thick polyester film, measured on steel at room temperature (20°C) at a peeling speed of 300 mm / min).

[0154] A preferred process is a process for producing composite films which comprises bonding at least two films to one another using the aqueous laminating adhesive composition.

[0155] The laminating adhesive composition or a preparation formulated accordingly is preferably applied to the large-surface- area substrates to be bonded at a layer thickness of 0.1 to 20 g / m2, particularly preferably 1 to 7 g / m2or 1 to 5 g / m2. After a short time for evaporation of the dispersion water (preferably after 1 to 60 seconds) the coated substrate may then be laminated with a second substrate, wherein the temperature may be for example 20°C to 200°C, preferably 20°C to 100°C, and the pressure may be for example 100 to 3000 kN / m2, preferably 300 to 2000 kN / m2.

[0156] In the process according to the invention for composite film lamination at least two films are bonded to one another with the two-component lamination adhesive wherein the instant peel force at 23°C is preferably more than 1 .0 N / 15mm, and the peel force after 5 minutes at 65°C is more than 4 N / 15 mm, measured as described in the examples.

[0157] In the process according to the invention at least one of the films may be printed or metallized on the side coated with the lamination adhesive. Suitable film substrates are, for example, polymer films, in particular made of thermoplastic polyolefins (TPO) such as polyethylene (PE), polypropylene (PP), for example oriented, preferably biaxially oriented, polypropylene (OPP) or unoriented polypropylene (OPP), ethylene / vinyl acetate copolymers (EVA), ASA (acrylonitrile / styrene / acrylate copolymers), PUR (polyurethane), polyamide (PA), polyester, preferably polyethylene terephthalate (PET), polyvinyl chloride (PVC) especially plasticized PVC, polyacetate, poly(meth)acrylates, polycarbonates or their plastic alloys, cellulose acetate, cellophane, polymer films coated (by vapor deposition) with metal, for example aluminium, (metallized films for short) such as metallized polyolefin films or metallized polyester films for example or metal foils, for example made of tin or aluminium. The film substrate is preferably selected from the group consisting of polyethylene, oriented polypropylene, unoriented polypropylene, polyamide, polyethylene terephthalate, polyacetate, cellophane, metallized films and metal foils. The polymer films, in particular polyolefin films, may optionally have been corona pre-treated. The films (carrier film) are particularly preferably selected from polyethylene, oriented polypropylene, unoriented polypropylene, polyamide, polyethylene terephthalate, polyacetate and cellophane.

[0158] The recited films may be bonded to one another or to a film of another type, for example polymer films to metal foils, different polymer films to one another, etc. The recited films may also have been printed with printing inks for example. The thickness of the film substrates may be for example from 5 to 100 pm, preferably from 5 to 40 pm.

[0159] In the case of composite films, the material of a first film is preferably selected from OPP, OPP, PE, PET and PA and the material of a second film is preferably selected from OPP, OPP, PE, PET, PA and metal foil. In one embodiment of the invention the first film and / or the second film is printed or metallized on the respective side which is coated with the dispersion adhesive composition.

[0160] The composite films obtainable according to the invention are suitable especially for the production of flexible packaging, for example for packaging foodstuffs.

[0161] Surface treatment of the film substrates before coating with the lamination adhesive is not absolutely necessary. However, better results can be obtained if the surfaces of the film substrates are modified prior to coating. Customary surface treatments may be employed in this case to amplify the adhesive effect, for example primers, plasma treatment or corona treatment. The corona treatment or other surface treatments are carried out to the extent required for sufficient wettability with the coating composition. Customarily, corona treatment of approximately 10 watts per square meter per minute is sufficient for this purpose. Alternatively, or in addition it is optionally also possible to use primers or tie coats between film substrate and adhesive coating. Furthermore, other, additional functional layers may be present on the composite films, examples being barrier layers, print layers, colour layers or varnish layers, or protective layers. These functional layers may be located externally, i.e., on the side of the film substrate facing away from the adhesive-coated side, or internally, between film substrate and adhesive layer.

[0162] Suitable exemplary application weights for composite film production are: from 0.1 to 20 g, particularly preferably 1 to 7 g, 1 to 6 g or 1 to 5 g of solid per m2for other technical laminates: from 0.5 to 100 g, preferably from 2 to 80 g, very particularly preferably from 10 to 70 g of solid per m2.

[0163] In addition to the composite film lamination the process according to the invention may also be employed in further industrial lamination processes, for example for producing automotive interior parts, for furniture lamination and for glossy film lamination. Contemplated substrates for bonding then include for example those made of wood, metal, plastic, leather, fibre moldings, for example MDF sheets, or paper. In glossy film lamination transparent polymer films are bonded to paper substrates. When used for surface decoration of a solid carrier with a film substrate coated according to the invention, for example a decorative film, the film substrate coated according to the invention is bonded for example to articles made of wood, including bound wood fibre materials such as fibreboards or other boards made of cellulose materials, metal or plastic. For example, furniture or furniture parts are laminated with the coated film substrate or automotive interior parts are coated with the coated film substrate made of PVC or TPO for example. Polyurethane dispersions are particularly suitable as an adhesive for lamination of rigid shaped articles with flexible decorative films.

[0164] In the process of lamination, the lamination adhesive is applied to the surface-area substrates to be bonded, by means, for example, of knife coating, spreading, etc. Customary coating techniques may be employed, examples being roller coating, reverse roller coating, gravure roller coating, reverse gravure roller coating or flexo coating. The coated substrate may then be laminated with a second substrate, the temperature can for example be 20 to 200°C, preferably 20 to 100°C, and the pressure can, for example, be 100 to 3000 kN / m2, preferably 300 to 2000 kN / m2. A film coated with lamination adhesive preferably runs through a dryer before a second substrate is co-laminated. The web speed of the film substrate is preferably from 50 to 500 m / min, for example at least 100 m / min, for example from 100 to 400 m / min or from 100 to 300 m / min.

[0165] A subject of the invention is also the use of the two-component lamination adhesive as described herein for film-to- film lamination or for film-to-paper lamination.

[0166] A subject of the invention is also a laminated product produced according to the process as described herein wherein the article produced by the process is a composite film, wherein at least two films are bonded to one another using the two-component lamination adhesive; or wherein the article produced is a glossy film wherein a transparent film is bonded to a paper substrate.

[0167] Examples

[0168] Materials:

[0169] Basonat® LR9056 crosslinker; emulsifier modified polyisocyanate based on isocyanurated hexamethylene diisocyanate

[0170] Lupranol® 1000 polypropylene glycol with molecular weight of 2000; OH number 55 mg KOH / g (DIN 53 240)

[0171] Example 1 (comparison)

[0172] Aqueous polyacrylate dispersion according to example 4 of WO 98 / 23656, polymer made of 56 wt.% n-butyl acrylate, 28 wt.% ethyl hexyl acrylate, 10 wt.% methyl methacrylate, 3 wt.% styrene and 3 wt.% acrylic acid; Tg: -34 °C.

[0173] Addition of 2 wt.% of Basonat® LR9056 crosslinker Example 2 (comparison)

[0174] Aqueous polyacrylate dispersion according to example 5 of WO 98 / 23656, polymer made of 51 wt.% n-butyl acrylate, 33 wt.% ethyl hexyl acrylate, 13 wt.% styrene and 3 wt.% acrylic acid; Tg: -34°C

[0175] Addition of 2 wt.% of Basonat® LR9056 crosslinker

[0176] Example 3 (comparison)

[0177] Aqueous polyacrylate dispersion according to example 4 of WO 00 / 50480, polymer made of 84 wt.% n-butyl acrylate, 15 wt.% methyl methacrylate, 1 wt.% acrylic acid;

[0178] Tg: -30 °C

[0179] Addition of 2 wt.% of Basonat® LR9056 crosslinker

[0180] Example 4 (comparison)

[0181] Aqueous polyacrylate dispersion; polymer made by free-radical emulsion polymerization of:

[0182] 57 wt.% 2-ethyl hexyl acrylate, 33 wt.% styrene, 6 wt.% 2-hydroxyethyl methacrylate, 2 wt.% n-butyl acrylate, 2 wt.% glycidyl methacrylate; Tg: -12 °C

[0183] Addition of 2 wt.% of Basonat® LR9056 crosslinker

[0184] Example 5 (comparison)

[0185] Aqueous polyurethane dispersion: polyurethane made of

[0186] 0.36 mole propylene glycol (OH number 56), 0.79 mole toluene diisocyanate (80% 2,4-isomer, 20% 2,6-isomer), 0.43 mole dimethylolpropionic acid, neutralized with 0.11 mole NaOH.

[0187] Final solids content 53%, pH of 7.

[0188] Addition of 2 wt.% of Basonat® LR9056 crosslinker

[0189] Example 6

[0190] Aqueous polymer dispersion of a blend of polymers, 1 :1 weight ratio:

[0191] First polymer: polyacrylate polymer of example 4

[0192] Second polymer: polyurethane polymer of example 5

[0193] Addition of 2 wt.% of Basonat® LR9056 crosslinker

[0194] Tego® Antifoam 2291 0.56 parts by weight per 100 parts by weight of polymers

[0195] Example 7

[0196] Aqueous polymer dispersion of a blend of polymers, 1 :1 weight ratio:

[0197] First polymer: polyacrylate made by free-radical emulsion polymerization of:

[0198] 79 wt.% 2-octyl acrylate, 15 wt.% styrene, 6 wt.% 2-hydroxyethyl methacrylate; Tg: -25 °C

[0199] Second polymer: polyurethane polymer of example 5

[0200] Addition of 2 wt.% of Basonat® LR9056 crosslinker Performance tests:

[0201] Film-to-film laminates are produced from two clear, transparent films.

[0202] A first film is a polyethylene terephthalate film of 250 pm thickness.

[0203] A second film is a polyethylene film of 85 pm thickness.

[0204] Application weight: 2 - 3 g / m2

[0205] Web speed: 19 m / min; 3 bar pressure at room temperature (23 °C)

[0206] A 2-component lamination adhesive is made by mixing the polymer dispersion with the crosslinker. The 2-component adhesive is coated onto the first film with an application weight of 2 - 3 g / m2. The second film is laminated onto the coated first film at a web speed of 9 m / min, applying 3 bar pressure at room temperature (23 °C). For the high temperature peel force measurements, the film-to-film laminate is subsequently stored for 24 h at room temperature under standard conditions (23 °C, 50% relative humidity).

[0207] Peel force measurement

[0208] The film-to-film laminate is cut into strips 15 millimeters wide. The laminate strip is pulled apart on a Zwick tensile testing machine and the force required to achieve this is recorded. The test takes place on a tensile testing machine at an angle of 90 degrees (T-test) and a removal velocity of 100 mm / min. The test strip is opened up on one side, with one of the resultant ends being clamped into the upper jaw and the other into the lower jaw of the tensile testing machine, and the test is commenced. The result reported is the average maximum of the force from 3 individual measurements, in N / 15 mm.

[0209] The instant peel force is the result as measured at 23 °C immediately after lamination without storing of the laminate. The high temperature peel force is the result after storage of the laminate for 24 h at room temperature under standard conditions and then heating the laminate to 65°C for 5 minutes.

[0210] Assessment of risk of telescoping, static shear strength

[0211] The effect of telescoping of wound-up rolls of laminates can be correlated with a static shear test at higher temperature as this is a measure for the softness of the adhesive film. The test is designed to measure the shear strength of the adhesive by applying a force parallel to the surface of the bonded materials. It is tested without crosslinker as the effect is more pronounced but can be correlated to crosslinked systems.

[0212] For the test a PET film (250 pm thickness) is coated with 2 to 3 g (dry) / m2of the adhesive and then laminated to a PET film (250 pm) at room temperature and 3 bar lamination pressure. The length of the laminated area is 20 mm. After storing for 24 h at room temperature, the laminate is cut into test strips of 15 mm in width. To determine the shear strength the test strips are subjected to hanging stress with a 0.5 kg weight at 50°C. The measure of shear strength is the time until the weight falls off.

[0213] The results are summarized in Table 1. Table 1 : appliciation test results x> Comparative example

[0214] Good peel force values are more than 1.0 N / 15 mm for the instant peel force and more than 4 N / 15 mm for the high temperature peel force. The data show that examples 6 and 7 provide high instant peel force and high high temperature peel force while simultaneously providing a low risk for telescoping. Comparative examples 1 to 4 provide low risk for telescoping but low peel forces. Comparative example 5 provides high peel forces but also a high risk of telescoping.

Claims

Claims1 . A two-component lamination adhesive, wherein one component of the lamination adhesive is in the form of an aqueous polymer dispersion comprising dispersed polymer particles of(I) at least one first polymer which is producible by free-radical emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers comprising(a) at least 49%, preferably from 50 to 90% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of C2- to C12-alkyl acrylates and C2- to C 12-alkyl methacrylates;(b) 5 to 50%, preferably from 9 to 40% by weight, based on the total amount of monomers, of styrene;(c) 0.1 to 10%, preferably from 0.5 to 10% by weight, based on the total amount of monomers, of at least one hydrophilic ethylenically unsaturated monomer with at least one hydrophilic group selected from acid groups and hydroxy groups(d) 0 to 10% by weight, based on the total amount of monomers, of at least one further ethylenically unsaturated monomer distinct from the monomers a), b) and c), wherein the glass transition temperature of the first polymer is more than minus 30 °C, preferably at least minus 25 °C, more preferably from minus 25 to + 5 °C, measured by differential scanning calorimetry at a heating rate of 20°C / min; and(II) at least one second polymer which is an adhesive polymer selected from polyurethanes; and wherein the second component of the lamination adhesive comprises a crosslinking compound capable of crosslinking the first component.

2. The two-component lamination adhesive according to claim 1 , wherein the weight ratio of first polymer to second polymer is from 1 :2 to 2:1, preferably from 1 :1.5 to 1.5:1.

3. The two-component lamination adhesive according to claim 1 or 2, wherein monomer (a) is at least one monomer selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2-propylheptyl acrylate.

4. The two-component lamination adhesive according to any of claims 1 to 3, wherein monomer (c) is an ethylenically unsaturated monomer with at least one acid group and is at least one monomer selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylacetic acid, vinyllactic acid, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, sulfopropyl acrylate, sulfopropyl methacrylate; or wherein monomer (c) is an ethylenically unsaturated monomer with at least one hydroxy group and is selected from the group consisting of hydroxyethyl acrylate, hydroxyethylmethacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate, 4-hydroxy butyl acrylate and 4-hydroxy butyl methacrylate.

5. The two-component lamination adhesive according to any of claims 1 to 4, wherein monomer (d) is at least one monomer selected from the group consisting of methyl acrylate, methyl methacrylate, vinyl esters of carboxylic acids comprising up to 20 carbon atoms, vinyl aromatics having up to 20 carbon atoms, vinyl halides, vinyl ethers of alcohols comprising 1 to 10 carbon atoms, aliphatic hydrocarbons having 2 to 8 carbon atoms and one or two double bonds, acrylamide, methacrylamide, C1-C10 aminoalkyl(meth)acrylates, nitriles of alpha-, beta- monoethylenically unsaturated C3-C8 carboxylic acids, bifunctional monomers which as well as an ethylenically unsaturated double bond have at least one group selected from glycidyl group, oxazoline group, ureido group and ureido-analogous group, and crosslinking monomers which have more than one radically polymerizable group, more particularly two or more (meth)acrylate groups.

6. The two-component lamination adhesive according to any of claims 1 to 5, wherein the first polymer is producible by free-radical emulsion polymerization of ethylenically unsaturated, free-radically polymerizable monomers comprising(a) from 50 to 90% by weight, based on the total amount of monomers, of at least one monomer selected from the group consisting of ethyl acrylate, propyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-hexyl acrylate, cyclohexyl (meth)acrylate, 2-octyl acrylate, 2-ethylhexyl acrylate and 2-propylheptyl acrylate;(b) from 9 to 40% by weight, based on the total amount of monomers, of styrene;(c) from 0.5 to 10% by weight, based on the total amount of monomers, of at least one hydrophilic ethylenically unsaturated monomer with at least one hydrophilic group selected from acid groups and hydroxy groups, wherein the hydrophilic monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylacetic acid, vinyllactic acid, vinylsulfonic acid, styrenesulfonic acid, acrylamidomethylpropanesulfonic acid, sulfopropyl acrylate, sulfopropyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate or hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate;(d) 0 to 10% by weight, based on the total amount of monomers, of at least one further ethylenically unsaturated monomer distinct from the monomers a), b) and c).

7. The two-component lamination adhesive according to any of claims 1 to 6, wherein the second polymer is a polyurethane constructed from a) at least one monomeric diisocyanate, b) at least one diol, of which b1) 10 to 100 mol%, based on the total amount of the diols (b), have a molecular weight of 500 to 5000 g / mol and b2) 0 to 90 mol%, based on the total amount of the diols (b), have a molecular weight of 60 to 500 g / mol,c) at least one monomer distinct from the monomers (a) and (b) having at least one isocyanate group or at least one isocyanate-reactive group which further bears at least one hydrophilic group or a potentially hydrophilic group, and d) optionally at least one further compound distinct from the monomers (a) to (c) having at least two reactive groups selected from alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups, and e) optionally at least one monofunctional compound distinct from the monomers (a) to (d) having a reactive group which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group.

8. The two-component lamination adhesive according to any of claims 1 to 7, wherein the diisocyanates a) are at least one diisocyanate selected from diisocyanates of the formula X(NCO)2, wherein X represents an acyclic aliphatic hydrocarbon radical having 4 to 15 carbon atoms, a cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms, an aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 7 to 15 carbon atoms, preferably selected from the group consisting of hexamethylene diisocyanate, 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, 2,6-diisocyanatotoluene, 2,4- diisocyanatotoluene and tetramethylxylylene diisocyanate or a mixture thereof; the diols b1) are at least one diol selected from polyester diols, polycarbonate diols and polyether diols; and the compound c) is at least one compound selected from dihydroxycarboxylic acids, diaminocarboxylic acids and diaminosulfonic acids.

9. The two-component lamination adhesive according to any of claims 1 to 8, wherein the second polymer is characterized by being amorph, and / or has a K-value between 20 to 80, and / or has a glass transition temperature of minus 60 °C to minus 10 °C, measured by differential scanning calorimetry at a heating rate of 20°C / min.

10. The two-component lamination adhesive according to any of claims 1 to 9, wherein the first polymer, the second polymer or both are at least partly made of bio based or recycled material.

11. The two-component lamination adhesive according to any of claims 1 to 10, wherein the crosslinking compound of the second component of the lamination adhesive is at least one compound selected from the group consisting of polyisocyanates and carbodiimides; the polyisocyanates are preferably at least one polyisocyanate selected from the group consisting of isocyanurates, iminooxadiazinediones, biurets, uretdiones, urethanes, and allophanates, and are obtainable by reacting at least one monomeric isocyanate, wherein the monomeric isocyanate is at least one monomeric isocyanate preferably selected from the group consisting of 1,6-hexamethylene diisocyanate, 1,3- bis(isocyanatomethyl)cyclohexane, isophorone diisocyanate, and 4,4'- or 2,4'-di(isocyanatocyclohexyl)methane, preferably 1,6-hexamethylene diisocyanate or isophorone diisocyanate; wherein the crosslinking compound of the second component of the lamination adhesive is used in a weight amount ratio of the crosslinking compoundto the first and second polymer of preferably from 1 to 5 parts by weight per 100 parts by weight of the sum of the polymers.

12. The two-component lamination adhesive according to any of claims 1 to 11, wherein the instant peel force at 23°C is more than 1.0 N / 15 mm, and the peel force after 5 minutes at 65°C is more than 4 N / 15 mm, measured as described in the examples.

13. The two-component lamination adhesive according to any of claims 1 to 12, wherein the first component of the two-component lamination adhesive is an aqueous composition comprising(I) from 25% to 70% by weight of the at least one first polymer;(ii) from 25% to 70% by weight of the at least one second polymer;(ill) from 0.25% to 5% by weight of one or more additives, preferably selected from the group consisting of defoamers, preservatives, UV stabilizers, catalysts, drying agents, antistatic agents, flame retardants, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, plasticizers, levelling agents, tackifiers, wetting agents or chelating agents.

14. Process of lamination, in which two substrates are bonded together wherein a) a first substrate in the form of a first film or paper is provided, b) a second substrate is provided, selected from paper and a second film that may be the same or different from the first film, c) the two-component adhesive according to any of claims 1 to 13 is provided, and d) the two-component adhesive is applied onto the first substrate and / or onto the second substrate, optionally being allowed to dry, and the first substrate is laminated onto the second substrate.

15. The process according to the preceding claim, wherein the process is a film-to-film lamination or a film-to-paper lamination and the material of a carrier film is selected from the group consisting of polyethylene, oriented polypropylene, unoriented polypropylene, polyamide, polyethylene terephthalate, polyacetate, cellophane.

16. A laminated product produced according to the process according to any of claims 14 to 15, wherein the article produced by the process is a composite film, wherein at least two films are bonded to one another using the two-component lamination adhesive; or wherein the article produced is a glossy film wherein a transparent film is bonded to a paper substrate.

17. Use of the two-component lamination adhesive of any of claims 1 to 13 for film-to-film lamination or for film-to- paper lamination.

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