EP3538586A1

EP3538586A1 - Dual-curing coating compositions

Info

Publication number: EP3538586A1
Application number: EP17801429.6A
Authority: EP
Inventors: Jörg TILLACK; Dirk Achten; Paul Heinz; Richard MEISENHEIMER; Thomas Buesgen; Michael Ludewig; Christoph TOMCZYK; Roland Wagner
Original assignee: Covestro Deutschland AG
Current assignee: Covestro Deutschland AG
Priority date: 2016-11-14
Filing date: 2017-11-14
Publication date: 2019-09-18
Also published as: WO2018087382A1; EP3538584A1; EP3538583A1; JP2019535554A; WO2018087399A1; US20200190245A1; EP3538585A1; KR102388093B1; CN109923143B; CN109923142A; EP3538584B1; CN109963890A; JP7216644B2; CN109923143A; WO2018087395A1; US11613072B2; US20180133953A1; CN114874411A; US20190367665A1; US10449714B2

Abstract

The present invention relates to polymerizable compositions which contain components that can be crosslinked both via isocyanurate bonds and by a radical reaction mechanism. The invention further relates to methods by way of which polymers can be produced from said compositions.

Description

Dual cure coating compositions

The present invention relates to polymerizable compositions containing components that can be crosslinked by isocyanurate bonds as well as by a free-radical reaction mechanism. It further relates to methods by which polymers can be made from these compositions.

WO 2015/155195 describes a composite material obtainable from a reinforcing material and a polyurethane composition consisting of at least one polyisocyanate (PIC), a PIC-reactive component consisting of at least one polyol and at least one methacrylate having OH groups, and a radical initiator. The addition reaction between PIC and OH groups occurs simultaneously with the free-radical initiated chain polymerization of the methacrylates. A disadvantage of the method used in addition to the short pot / gel times of the polyurethane compositions, the fact that in the production of polyurethanes, the mixing ratio of the components, in particular of the polyisocyanate and the polyol is limited by the need, the molar ratio of isocyanate and Keep isocyanate-reactive groups close to 1: 1.

WO 2016/087366 describes a free-radically polymerizable composition consisting of a polyurethane which contains double bonds and a reactive diluent based on various methacrylates. Disadvantages here are the two-stage reaction procedure (in the first stage, the reaction of the hydroxymethacrylate with an isocyanate takes place, and in the second stage the reaction of the isocyanate-bound (meth) acrylates to polyacrylates takes place in order to obtain a crosslinked mass). Another disadvantage is the need to work precisely stoichiometric to avoid free unreacted isocyanate.

US Pat. No. 6,133,397 and PCT / EP2017 / 073276 describe coating compositions which are cured mainly by crosslinking of isocyanate groups with one another. Among others, isocyanurate groups are formed which impart advantageous properties to the resulting coatings.

The low monomer content polyisocyanate compositions described in these applications as starting materials have a relatively high viscosity, which may be a hindrance in some applications.

The addition of monomeric polyisocyanates as reactive diluents is undesirable for reasons of occupational safety in many cases, since these compounds are on the one hand easily volatile and on the other hand have an irritating effect. Alternatively, conventional organic solvents can be used to reduce the viscosity. However, these are for the sake of Environmental protection disadvantageous because they are released during or after the polymerization in the ambient air.

At the same time, it is desirable for coating applications if the viscosity of the coating composition can be increased as far as immediately after application to the extent that the coating is prevented from running off an inclined surface. Since the crosslinking reaction of isocyanate groups is e.g. to isocyanurate groups usually takes at least a few minutes, the compositions described in US 6,133,397 do not meet this requirement.

Desirable therefore are compositions whose viscosity can be adjusted in the unprocessed state without the use of organic solvents as freely as possible according to the requirements of each application and whose viscosity can be increased as quickly as possible after application to a surface. As far as such coatings are used for producing coatings, the resulting coatings should also have good optical properties, in particular clarity.

This object is achieved by the embodiments of the invention disclosed in the claims and in the description below.

In a first embodiment, the present invention relates to a coating composition having a ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0 to 1.0 comprising a) an isocyanate component A;

b) at least one trimerization catalyst C; and

c) at least one component selected from the group consisting of components B, D and E, wherein component B has at least one ethylenic double bond but no isocyanate-reactive group;

component D in a molecule has at least one isocyanate-reactive group and at least one ethylenic double bond; and

the component E in a molecule has both at least one isocyanate group and at least one ethylenic double bond.

The isocyanate component A allows the formation of a polymer formed by the addition of isocyanate groups. In particular, isocyanurate groups are formed. The crosslinking of the isocyanate groups contained in the isocyanate component A gives the polymer the majority its mechanical and chemical stability. The crosslinking of the isocyanate groups is mediated by the trimerization catalyst C.

Components B, D and E are each characterized by the presence of an ethylenic double bond. This double bond is prerequisite for the fact that a second crosslinking mechanism is available in addition to the polyaddition of the isocyanate groups in the polymerizable composition. Each of these components allows crosslinking by radical polymerization. This is a crosslinking mechanism that allows the buildup of viscosity over a few seconds. Here, the use of individual ones of these components or certain combinations of components has specific advantages:

Component B reduces the viscosity of the polymerizable composition and can be rapidly crosslinked by free-radical polymerization and thus used for rapid viscosity buildup. If only one component B without components D or E is present in the polymerizable composition, two different polymer networks are formed by the two different crosslinking mechanisms. This can lead to turbidity in the finished product and possibly to poorer mechanical properties.

In application fields where this is to be avoided, component B is used in combination with a component D or E. It can also be used in combination with both components. The components D and E mediate the crosslinking of the resulting by free radical polymerization network of component B with the polyaddition of the isocyanate groups resulting polymer of the isocyanate A. They ensure that the polymer is not two separate polymer networks of components A and B, but a uniform polymer network.

Even when used without an additional component B, components D and E allow the construction of a polymer network by free radical polymerization. Similar to the exclusive use of a component B, the rapid build-up of viscosity after application of the composition according to the invention is thus made possible. Unlike component B, however, components D and E are suitable only to a limited extent as reactive diluents.

In a preferred embodiment of the present invention, the polymerizable composition contains at least one of the two components D and E, but no component B.

In another preferred embodiment, the composition according to the invention contains a component B and at least one of the two components D and E. Particularly preferred is the combination of B and D. In a preferred embodiment, the proportions of components B, D and E are adjusted so that the coating composition does not after the radical polymerization of the ethylenic double bonds on a vertical surface in a period of at least 30 seconds, preferably at least 2 minutes and more preferably at least 10 minutes expires. A coating composition does not proceed if, after the aforementioned time, no difference in coating thickness is visually detectable between the upper end of the surface and the lower end thereof.

Whether a coating composition meets this criterion can be determined by simple preliminary tests. The composition is applied to a surface and treated with actinic radiation to initiate radical polymerization. Subsequently, the surface for the above period at 23 ° C (room temperature) is stored vertically and then visually inspected.

A stability of a coating results from the interaction of coating thickness and viscosity. The higher the coating thickness, the higher the viscosity of the coating must be.

According to a particular embodiment of the invention, coating thicknesses of at least 0.005 mm, preferably at least 0.02 mm and very particularly preferably at least 0.04 mm and at most 5 mm, preferably at most 0.5 mm and very particularly preferably at most 0.1 mm are desired.

According to a further preferred embodiment, the proportion of components B, D and E in the composition according to the invention is such that the viscosity of the coating after polymerization caused by actinic radiation at least doubles, preferably quadruples, and particularly preferably increases tenfold.

According to another preferred embodiment, the dynamic viscosity according to EN ISO 2884-1: 2006 in a cone-plate viscometer at room temperature measured after polymerization with actinic radiation at least 200 mPas, preferably at least 500 mPas, more preferably at least 1,000 mPas, most preferably at least 10,000 mPas and even more preferably at least 100,000 mPas.

In a preferred embodiment, the polymerizable composition according to the invention contains the isocyanate component A and the component B preferably in an amount ratio which the viscosity of the undiluted isocyanate component to at most 75%, preferably at most 25%, more preferably at most 5% and most preferably lower than 1% of the viscosity of an undiluted isocyanate component A. The presence of at least one component D or E is particularly preferred in this embodiment.

In a preferred embodiment, the proportion of component A to the total amount of components B, D and E is such that the polymerizable composition prior to each crosslinking has a viscosity at room temperature of at most 100,000 mPas, more preferably at most 10,000 mPas, even more preferably at most 1000 mPas, and most preferably at most 100 mPas.

The polymer obtainable by polymerization of the coating composition according to the invention obtains its advantageous properties quite substantially by crosslinking of the isocyanate groups with one another. For this reason, it is essential to the invention that the ratio of isocyanate groups to the total amount of isocyanate-reactive groups in the polymerizable composition is limited so that a clear molar excess of isocyanate groups is present. The molar ratio of isocyanate groups of the isocyanate component to isocyanate-reactive groups in the polymerizable composition is therefore at least 2.0 to 1.0, preferably at least 3.0 to 1.0, more preferably at least 4.0 to 1.0 and even more preferably at least 8.0 to 1.0. "For the purposes of the present application," isocyanate-reactive groups "are hydroxyl, thiol, carboxyl and amino groups, amides, urethanes, acid anhydrides and epoxides The isocyanate groups present are contained in the components A and, if present, E. The isocyanate-reactive groups can in principle be present in all other components with the exception of component B.

In comparison with the polyurethane resins known from WO 2015/155195 with additional radiation curing, the use of the polymerizable composition according to the invention allows greater flexibility in the selection of the proportions of the individual components. When a polyurethane or a polyurea is to be obtained, the molar ratio of isocyanate groups to isocyanate-reactive groups must be close to 1: 1 as far as possible. However, according to the present invention, there is a significant excess of isocyanate groups, which is therefore not only acceptable, but even desirable, because the resulting polymer owes its advantageous properties quite substantially to the reaction of isocyanate groups with other isocyanate groups. The resulting structures, in particular the isocyanurate groups, lead to polymers with particular hardness and particular resistance to chemicals. Isocyanate component A

For the purposes of the invention, "isocyanate component A" refers to the isocyanate component in the initial reaction mixture, in other words, the sum of all compounds in the initial reaction mixture which have isocyanate groups with the exception of component E. The isocyanate component A is therefore used as starting material If "isocyanate component A" is used here, in particular "preparation of isocyanate component A", then this means that isocyanate component A exists and is used as starting material The isocyanate component A preferably contains at least one polyisocyanate.

The term "polyisocyanate" as used herein is a collective term for compounds containing in the molecule two or more isocyanate groups (which is understood by those skilled in the art to include free isocyanate groups of general structure -N = C = O) These polyisocyanates are the diisocyanates which have the general structure O = C = NRN = C = O, where R usually stands for aliphatic, alicyclic and / or aromatic radicals.

Because of the multiple functionality (> 2 isocyanate groups), a multitude of polymers (eg polyurethanes, polyureas and polyisocyanurates) and low molecular weight compounds (eg those with uretdione, isocyanurate, allophanate, biuret, Iminooxadiazinedione and / or oxadiazinetrione structure).

In this application, the term "polyisocyanates" refers to monomeric and / or oligomeric polyisocyanates alike, but to understand many aspects of the invention it is important to distinguish between monomeric diisocyanates and oligomeric polyisocyanates. "Oligomeric polyisocyanates" are referred to in this application. then it means polyisocyanates which are composed of at least two monomeric diisocyanate molecules, ie they are compounds which are or contain a reaction product of at least two monomeric diisocyanate molecules.

The preparation of oligomeric polyisocyanates from monomeric diisocyanates is also referred to herein as modifying monomeric diisocyanates. This "modification" as used herein means the reaction of monomeric diisocyanates to oligomeric polyisocyanates having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure.

For example, hexamethylene diisocyanate (HDI) is a "monomeric diisocyanate" because it contains two isocyanate groups and is not a reaction product of at least two polyisocyanate molecules:

HDI

Reaction products of at least two HDI molecules, which still have at least two isocyanate groups, are in contrast "oligomeric polyisocyanates" in the meaning of the invention .Parents of such "oligomeric polyisocyanates" are starting from the monomeric HDI, e.g. the HDI isocyanurate and the HDI biuret, each composed of three monomeric HDI building blocks:

(CH ₂ ) ₆ -NCO

(CH ₂ ) ₆ NCO

I I H l

OCN- (H ₂ C) ₆ "^ C" ^ (CH ₂ ) ₆ -NCO ΟΟΝ (ΟΗ ₂ ) ₆ ^{/ Ν} γ ΟΗ ₂ ) ₆ ΝΟΟ

O O

- Isocyanurate

(idealized structural formulas)

According to the invention, the weight fraction of isocyanate groups based on the total amount of isocyanate component A is at least 15% by weight.

In principle, monomeric and oligomeric polyisocyanates are equally suitable for use in the isocyanate component A according to the invention. Thus, the isocyanate component A may consist essentially of monomeric polyisocyanates or substantially of oligomeric polyisocyanates. But it can also contain oligomeric and monomeric polyisocyanates in any mixing ratios.

In a preferred embodiment of the invention, the isocyanate component A used as starting material in the trimerization is low in monomer (i.e., low in monomeric diisocyanates) and already contains oligomeric polyisocyanates. The terms "low in monomer" and "low in monomeric diisocyanates" are used interchangeably herein with respect to isocyanate component A.

Particularly practical results are obtained when the isocyanate component A is a proportion of monomeric diisocyanates in the isocyanate component A of at most 20 wt .-%, in particular at most 15 wt .-% or at most 10 wt .-%, each based on the weight of the isocyanate component A, has. The isocyanate component A preferably has a content monomeric diisocyanates of at most 5 wt .-%, preferably at most 2.0 wt .-%, particularly preferably at most 1.0 wt .-%, each based on the weight of the isocyanate component A, on. Particularly good results are obtained when the isocyanate component A is substantially free of monomeric diisocyanates. Substantially free means that the content of monomeric diisocyanates is at most 0.5% by weight, based on the weight of the isocyanate component A.

According to a particularly preferred embodiment of the invention, the isocyanate component A is completely or at least 80, 85, 90, 95, 98, 99 or 99.5 wt .-%, each based on the weight of the isocyanate component A, of oligomeric polyisocyanates. Here, a content of oligomeric polyisocyanates of at least 99 wt .-% is preferred. This content of oligomeric polyisocyanates refers to the isocyanate component A as provided. That the oligomeric polyisocyanates are not formed during the process according to the invention as an intermediate, but are already present at the beginning of the reaction in the isocyanate component used as starting material A.

Polyisocyanate compositions which are low in monomer or substantially free of monomeric isocyanates can be obtained by carrying out, after the actual modification reaction, in each case at least one further process step for separating off the unreacted excess monomeric diisocyanates. This monomer removal can be carried out in a particularly practical manner by processes known per se, preferably by thin-layer distillation under high vacuum or by extraction with suitable isocyanate-inert solvents, for example aliphatic or cycloaliphatic hydrocarbons, such as pentane, hexane, heptane, cyclopentane or cyclohexane.

According to a preferred embodiment of the invention, the novel isocyanate component A is obtained by modifying monomeric diisocyanates with subsequent removal of unreacted monomers.

According to a particular embodiment of the invention, however, a low-monomer isocyanate component A contains a monomeric foreign diisocyanate. Here, "monomeric foreign diisocyanate" means that it differs from the monomeric diisocyanates used to prepare the oligomeric polyisocyanates contained in the isocyanate component A.

An addition of monomeric foreign diisocyanate may be advantageous for achieving special technical effects, such as a particular hardness. Particularly practical results are obtained when the isocyanate component A is a proportion of monomeric foreign diisocyanate in the isocyanate component A of at most 20 wt .-%, in particular at most 15 wt .-% or at most 10 wt .-%, each based on the weight of the isocyanate component A, has. The isocyanate component A preferably has a monomeric foreign diisocyanate content of at most 5% by weight, preferably at most 2.0% by weight, particularly preferably at most 1.0% by weight, based in each case on the weight of the isocyanate component A.

According to a further particular embodiment of the process according to the invention, the isocyanate component A comprises monomeric monoisocyanates or monomeric isocyanates having an isocyanate functionality greater than two, i. with more than two isocyanate groups per molecule. The addition of monomeric monoisocyanates or monomeric isocyanates having an isocyanate functionality greater than two has been found to be advantageous for affecting the network density of the coating. Particularly practical results are obtained when the isocyanate component A is a proportion of monomeric monoisocyanates or monomeric isocyanates having an isocyanate functionality greater than two in the isocyanate component A of at most 20 wt .-%, in particular at most 15 wt .-% or at most 10 wt .-% , in each case based on the weight of the isocyanate component A. Preferably, the isocyanate component A has a content of monomeric monoisocyanates or monomeric isocyanates having an isocyanate functionality greater than two of at most 5 wt .-%, preferably at most 2.0 wt .-%, particularly preferably at most 1.0 wt .-%, each based on the weight of the isocyanate component A, on. Preferably, in the trimerization reaction according to the invention, no monomeric monoisocyanate or monomeric isocyanate with an isocyanate functionality greater than two is used.

According to the invention, the oligomeric polyisocyanates may in particular have uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures. According to one embodiment of the invention, the oligomeric polyisocyanates have at least one of the following oligomeric structural types or mixtures thereof:

Uretdione isocyanurate allophanate biuret iminooxadiazinedione oxadiazinetrione

According to a preferred embodiment of the invention, an isocyanate component A is used whose Isocyanuratstrukturanteil

According to a preferred embodiment of the invention, an isocyanate component A is used whose isocyanurate structure content is at least 50 mol%, preferably at least 60 mol%. %, more preferably at least 70 mole%, even more preferably at least 80 mole%, even more preferably at least 90 mole% and most preferably at least 95 mole% based on the sum of the oligomeric structures of the group consisting of uretdione , Isocyanurat-, allophanate, biuret, Iminooxadiazindion- and Oxadiazintrionstruktur in the isocyanate component A, is.

According to a further preferred embodiment of the invention, in the process according to the invention, an isocyanate component A which, in addition to the isocyanurate structure, contains at least one further oligomeric polyisocyanate with uretdione, biuret, allophanate, iminooxadiazinedione and oxadiazinetrione structure and mixtures thereof.

The proportions of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure in the isocyanate component A can be e.g. be determined by NM spectroscopy. The 13C-NMR spectroscopy, preferably proton-decoupled, may preferably be used in this case since the stated oligomeric structures give characteristic signals.

Irrespective of the underlying oligomeric structure (uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure), an oligomeric isocyanate component A to be used in the process according to the invention and / or the oligomeric polyisocyanates contained therein preferably has an (average) NCO Functionality of from 2.0 to 5.0, preferably from 2.3 to 4.5.

Particularly practical results are obtained when the isocyanate component A to be used according to the invention has a content of isocyanate groups of 8.0 to 28.0% by weight, preferably from 14.0 to 25.0% by weight, in each case based on the weight of the Isocyanate component A, has.

Preparation processes for the oligomeric polyisocyanates with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure to be used according to the invention in the isocyanate component A are described, for example, in J. Prakt. Chem. 336 (1994) 185-200, in DE-A 1 670 666, DE-A 1 954 093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053 and DE-A 3 928 503 or in EP-A 0 336 205, EP A 0 339 396 and EP-A 0 798 299.

According to an additional or alternative embodiment of the invention, the isocyanate component A according to the invention is defined by containing oligomeric polyisocyanates consisting of monomeric diisocyanates, regardless of the type of modification reaction used, while maintaining a degree of oligomerization of 5 to 45%, preferably 10 to 40% preferably 15 to 30% were obtained. By "degree of oligomerization" is the percentage of isocyanate groups originally present in the starting mixture which is consumed during the manufacturing process to form uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures.

Suitable polyisocyanates for the preparation of the isocyanate component A to be used in the process according to the invention and the monomeric and / or oligomeric polyisocyanates contained therein are any, in various ways, for example by phosgenation in the liquid or gas phase or on a phosgene-free route, such. by thermal urethane cleavage, accessible polyisocyanates. Particularly good results are obtained when the polyisocyanates are monomeric diisocyanates. Preferred monomeric diisocyanates are those which have a molecular weight in the range of 140 to 400 g / mol, with aliphatic, cycloaliphatic, araliphatic and / or aromatically bonded isocyanate groups, such as. B. 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-l, 5-diisocyanatopentane, l, 5-diisocyanato-2,2-dimethylpentane , 2,2,4- and 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,4-diisocyanato-3,3, 5-trimethylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, 1,3-diisocyanato-4-methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), isocyanato -l-methyl-4 (3) isocyanatomethylcyclohexane, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane (H12MDI), 1,3- and 1,4-bis (isocyanatomethyl) cyclohexane, bis (isocyanatomethyl) norbornane (NBDI), 4,4'-diisocyanato-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-3,3 ', 5,5'-tetramethyl-dicyclohexylmethane, 4,4'-diisocyanato-1' -bi (cyclohexyl), 4,4'-diisocyanato-3,3'-dimethyl-1, 1'-bi (cyclohexyl), 4,4'-diisocyanato-2,2 ', 5,5'-tetra-methyl -l, l'bi (cyclohexyl), 1,8-diisocyanato-p-menthane, 1,3-diisocyanato-adam Antan, l, 3-dimethyl-5,7-diisocyanatoadamantane, 1,3- and 1'-bis-fiso-cyanatomethylJbenzol (xyxlylene diisocyanate; XDI), 1,3- and 1,4-bis (1-isocyanato-1-methyl ethyl) benzene (TMXDI) and bis (4- (1-isocyanato-1-methylethyl) phenyl) carbonate, 2,4 and 2,6-diisocyanatotoluene (TDI), 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI), 1,5-diisocyanatonaphthalene and any mixtures of such diisocyanates. Other likewise suitable diisocyanates can be found, for example, in Justus Liebigs Annalen der Chemie, Volume 562 (1949) pp. 75-136.

Suitable monomeric monoisocyanates which can optionally be used in the isocyanate component A are, for example, n-butyl isocyanate, n-amyl isocyanate, n-hexyl isocyanate, n-heptyl isocyanate, n-octyl isocyanate, undecyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate, cetyl isocyanate, stearyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, 3- or 4-methylcyclohexyl isocyanate or any mixtures of such monoisocyanates. As a monomeric isocyanate having an isocyanate functionality greater than two, which may optionally be added to the isocyanate component A, is exemplified by 4-isocyanatomethyl-l, 8-octane diisocyanate (triisocyanatononane, TIN). According to one embodiment of the invention, the isocyanate component A contains at most 30% by weight, in particular at most 20% by weight, at most 15% by weight, at most 10% by weight, at most 5% by weight or at most 1% by weight. %, in each case based on the weight of the isocyanate component A, of aromatic polyisocyanates. As used herein, "aromatic polyisocyanate" means a polyisocyanate having at least one aromatic-bonded isocyanate group.

By aromatically bound isocyanate groups is meant isocyanate groups which are bonded to an aromatic hydrocarbon radical.

According to a preferred embodiment of the process according to the invention, an isocyanate component A is used which has exclusively aliphatically and / or cycloaliphatically bonded isocyanate groups.

By aliphatic or cycloaliphatic bound isocyanate groups is meant isocyanate groups which are bonded to an aliphatic or cycloaliphatic hydrocarbon radical. According to another preferred embodiment of the process according to the invention, an isocyanate component A is used which consists of or contains one or more oligomeric polyisocyanates, the one or more oligomeric polyisocyanates having exclusively aliphatically and / or cycloaliphatically bonded isocyanate groups.

According to a further embodiment of the invention, the isocyanate component A is at least 70, 80, 85, 90, 95, 98 or 99 wt .-%, each based on the weight of the isocyanate component A, of polyisocyanates exclusively aliphatic and / or cycloaliphatic bound Having isocyanate groups. Practical experiments have shown that particularly good results can be achieved with isocyanate components A in which the oligomeric polyisocyanates contained therein have exclusively aliphatically and / or cycloaliphatically bonded isocyanate groups.

According to a particularly preferred embodiment of the method according to the invention, a polyisocyanate A composition is used which consists of or contains one or more oligomeric polyisocyanates, wherein the one or more oligomeric polyisocyanates based on 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), isophorone diisocyanate (IPDI) or 4,4'-diisocyanatodicyclohexylmethane (H 12MDI) or mixtures thereof.

According to a further embodiment of the invention, in the process according to the invention, isocyanate components A having a viscosity of greater than 500 mPas and less than 200,000 mPas, preferably greater than 1,000 mPas and less than 100,000 mPas, more preferably greater than 1,000 mPas and less than 50,000 mPas and even more preferably greater than 1,000 mPas and less than 25,000 mPas, measured in accordance with DIN EN ISO 3219 at 21 ° C.

Component B

As component B, all compounds are suitable which contain at least one ethylenic double bond. This ethylenic double bond is crosslinkable by a radical reaction mechanism with other ethylenic double bonds. This condition preferably fulfills activated double bonds located between the - and the β-carbon atom adjacent to an activating group. The activating group is preferably a carboxyl or carbonyl group. Most preferably, component B is an acrylate, a methacrylate, the ester of an acrylate or the esters of a methacrylate. Preferably, the component B does not contain any of the isocyanate-reactive groups as defined above in this application and also no isocyanate group.

Preferred components B are components B1 with one, components B2 with two and components B3 with three of the ethylenic double bonds described above. Particularly preferred are Bl and / or B2.

In a preferred embodiment, component B used is a mixture of at least one component B1 and at least one component B2.

In a further preferred embodiment, a mixture of at least one component Bl and at least one component B3 is used as component B.

In still another preferred embodiment, component B is a mixture of at least one component B2 and at least one component B3.

In still another preferred embodiment, as component B, a mixture of at least one component Bl, at least component B2 and at least one component B3 is used. Preferably, a mixture of at least one component Bl with at least one component B2 is used. Here, the mass ratio of the components Bl and B2 is preferably between 30: 1 and 1: 30, more preferably between 20: 1 and 1:20, even more preferably between 1:10 and 10: 1, and most preferably between 2: 1 and 1: 2.

Preferred components Bl are methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, iso-propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, iso-octyl (meth) acrylate, decyl (meth) acrylate, benzyl ( meth) acrylate, Tetrahydrofurfuryl (meth) acrylate, octadecyl (meth) acrylate, dodecyl (meth) acrylate,

Tetradecyl (meth) acrylate, oleyl (meth) acrylate, 4-methylphenyl (meth) acrylate, benzyl (meth) acrylate, furfuryl (meth) acrylate, cetyl (meth) acrylate, 2-phenylethyl (meth) acrylate, isobornyl (meth) acrylate, neopentyl (meth) acrylate, methacrylamide and n-isopropylmethacrylamide.

Preferred components B2 are vinyl (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylates, 1,6-hexanediol di (meth) acrylate, neopentyl glycol propoxylate di (meth) acrylate, tripropylene glycol di (meth) acrylate, bisphenol A ethoxylated di (meth ) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hexamethylene glycol di (meth) acrylate, bisphenol A di (meth) acrylate and 4,4'-bis (2- (meth) acryloyloxyethoxy) diphenylpropane ,

Preferred components B3 are ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated glycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane ethoxytri (meth (acrylate, trimethylolpropane tri (meth) acrylate, alkoxylated tria (meth) crylate and tris (2- (meth) acryloylethyl) isocyanurate.

Trimerization catalyst C

The trimerization catalyst C may be mixed from one or more types of catalyst but contains at least one catalyst which effects the trimerization of isocyanate groups to isocyanurates or iminooxadiazinediones.

Suitable catalysts for the process according to the invention are, for example, simple tertiary amines, such as e.g. Triethylamine, tributylamine, Ν, Ν-dimethylaniline, N ethylpiperidine or N, N'-dimethylpiperazine. Suitable catalysts are also the tertiary hydroxyalkylamines described in GB 2 221 465, e.g. Triethanolamine, N-methyldiethanolamine, dimethylethanolamine, N-isopropyldiethanolamine and 1- (2-hydroxyethyl) pyrrolidine, or those known from GB 2 222 161, from mixtures of tertiary bicyclic amines, e.g. DBU, with simple low molecular weight aliphatic alcohols existing catalyst systems.

Also suitable as trimerization catalysts for the process according to the invention is a multiplicity of different metal compounds. Suitable examples are described in DE-A 3,240,613 as catalysts octoates and naphthenates of manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium or lead or mixtures thereof with acetates of lithium, sodium, potassium, Calciu m or barium, the known from DE-A 3 219 608 sodium and potassium salts of linear or branched alkanecarboxylic acids having up to 10 carbon atoms, such as propionic, butyric, valeric, caproic, heptanoic, caprylic, pelargonic, capric and Undecylic acid, the known from EP-A 0 100 129 alkali or alkaline earth metal salts of aliphatic, cycloaliphatic or aromatic mono- and polycarboxylic acids having 2 to 20 C atoms, such as, for example, sodium or potassium benzoate, the alkali phenolates known from GB-PS 1 391 066 and British Patent 1 386 399, such as, for example, sodium or potassium phenolate, the alkali and alkaline earth oxides, hydroxides, carbonates, alcoholates and phenolates known from GB 809 809, alkali metal salts of enolisable compounds and metal salts of weak aliphatic or cycloaliphatic carboxylic acids, such as sodium methoxide, sodium acetate, potassium acetate, sodium acetoacetic ester, lead 2 ethylhexanoate and lead naphthenate, the basic alkali metal compounds known from EP-A 0 056 158 and EP-A 0 056 159 complexed with crown ethers or polyether alcohols, for example complexed sodium or potassium carboxylates, the pyrrolidinone known from EP-A 0 033 581 Potassium salt, the mono- or polynuclear complex compound of titanium, zirconium and / or hafnium known from the application EP 13196508.9 such as zirconium tetra-n-butylate, zirconium tetra-2-ethylhexanoate and zirconium tetra-2-ethylhexylate, as well as tin compounds of the type described in European Polymer Journal, Vol. 16, 147-148 (1979), such as dibutyltin dichloride, diphenyltin dichloride, triphenylstannanol, Tributyltin acetate, tributyltin oxide, tin dioctoate, dibutyl (dimethoxy) stannane and tributyltin imidazolate.

Further suitable trimerization catalysts for the process according to the invention are, for example, the quaternary ammonium hydroxides known from DE-A 1 667 309, EP-A 0 013 880 and EP-A 0 047 452, such as, for example, US Pat. tetraethylammonium,

Trimethylbenzylammonium hydroxide, N, N-dimethyl-N-dodecyl-N- (2-hydroxyethyl) ammonium hydroxide, N- (2-hydroxyethyl) -N, N-dimethylN- (2,2'-dihydroxymethylbutyl) -ammonium hydroxide and (2-hydroxyethyl) -l, 4-diazabicyclo [2.2.2] octane hydroxide (monoadduct of ethylene oxide and water on 1,4-diazabicyclo [2.2.2] octane) obtained from EP-A 37 65 or EP -A 10 589 known quaternary hydroxyalkylammonium hydroxides, such as N, N, N-trimethyl-N- (2-hydroxyethyl) -ammonium hydroxide, the trialkylhydroxyalkylammonium carboxylates known from DE-A 2631733, EP-A 0 671 426, EP-A 1 599 526 and US 4,789,705, such as e.g. N, N, N-trimethyl-N-2-hydroxypropylammonium p-tert-butylbenzoate and N, N, N-trimethyl-N-2-hydroxypropylammonium 2-ethylhexanoate, those known from EP-A 1 229 016 quaternary Benzylammonium carboxylates, such as N-benzyl-N, N-dimethyl-N-ethylammonium pivalate, N-benzyl-N, N-dimethyl-N-ethylammonium 2-ethylhexanoate, N-benzyl-N, N, N-tributylammonium 2-ethylhexanoate, N, N-dimethyl-N-ethyl-N- (4-methoxybenzyl) ammonium 2-ethylhexanoate or N, N, N-tributyl-N- (4-methoxybenzyl) ammonium pivalate, which are known from WO 2005/087828 tetrasubstituted ammonium a-hydroxycarboxylates, such as Tetramethylammonium lactate, the quaternary ammonium or phosphonium fluorides known from EP-A 0 339 396, EP-A 0 379 914 and EP-A 0 443 167, e.g. N-methyl-N, N, N-trialkylammonium fluorides with C 8 -C 10 -alkyl radicals, N, N, N, N-tetra-n-butylammonium fluoride, Ν, Ν, Ν-trimethyl-N-benzylammonium fluoride, tetramethyl phosphonium fluoride .

Tetraethylphosphonium fluoride or tetra-n-butylphosphonium fluoride, the known from EP-A 0 798 299, EP-A 0 896 009 and EP-A 0 962 455 known quaternary ammonium and Phosphoniumpolyfluoride, such as benzyl-trimethylammoniumhydrogenpolyfluorid, from EP-A 0 668 271 known tetraalkylammonium alkyl carbonates, which are obtainable by reaction of tertiary amines with dialkyl, or betaine structurized quaternary Ammonioalkylcarbonate known from WO 1999/023128 known quaternary ammonium bicarbonates, such as choline bicarbonate, known from EP 0,102,482, from tertiary Amines and alkylating esters of acids of phosphorus available quaternary ammonium salts, such as reaction products of triethylamine, DABCO or N-methylmorpholine with Methanphosphonsäuredimethylester, or known from WO 2013/167404 tetrasubstituted ammonium salts of lactams, such as Trioctylammoniumcaprolactamat or Dodecyltrimethylammoniumcaprolactamat.

Further trimerization catalysts C which are suitable for the process according to the invention can be found, for example, in J.H. Saunders and K.C. Frisch, Polyurethanes Chemistry and Technology, p. 94 ff (1962) and the literature cited therein.

Particular preference is given to carboxylates and phenolates with metal or ammonium ions as the counterion. Suitable carboxylates are the anions of all aliphatic or cycloaliphatic carboxylic acids, preferably those with mono- or polycarboxylic acids having 1 to 20 C atoms. Suitable metal ions are derived from alkali or alkaline earth metals, manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium, tin, titanium, hafnium or lead. Preferred alkali metals are lithium, sodium and potassium, more preferably sodium and potassium. Preferred alkaline earth metals are magnesium, calcium, strontium and barium.

Very particular preference is given to the octoates and naphthenates described in DE-A 3 240 613 as catalysts of manganese, iron, cobalt, nickel, copper, zinc, zirconium, cerium or lead or mixtures thereof with acetates of lithium, sodium, potassium, calcium or barium.

Also very particularly preferred are sodium or potassium benzoate, the alkali phenolates known from GB-PS 1 391 066 and GB-PS 1 386 399, such as. As sodium or potassium phenolate, and known from GB 809 809 alkali and alkaline earth oxides, hydroxides, carbonates, alkoxides and - phenolates.

The trimerization catalyst C preferably contains a polyether. This is especially preferred when the catalyst contains metal ions. Preferred polyethers are selected from the group consisting of crown ether, diethylene glycol, polyethylene and polypropylene glycols. In the process according to the invention, it has proven to be particularly practical to use a trimerization catalyst B which contains as polyether a polyethylene glycol or a crown ether, more preferably 18-crown-6 or 15-crown-5. Preferably, the Trimiersierungskatalysator B contains a polyethylene glycol having a number average molecular weight of 100 to 1000 g / mol, preferably 300 g / mol to 500 g / mol and in particular 350 g / mol to 450 g / mol. Very particularly preferred is the combination of the above-described carboxylates and phenolates of alkali or alkaline earth metals with a polyether.

Component D

Component D is a compound which defines in a molecule at least one isocyanate-reactive group as defined earlier in this application and has at least one ethylenic double bond. The isocyanate-reactive group of component D may also be a uretdione group. Ethylenic double bonds are preferably those which are crosslinkable by a radical reaction mechanism with other ethylenic double bonds. Corresponding activated double bonds are defined in more detail for component B above in this application.

Preferred components D are alkoxyalkyl (meth) acrylates having 2 to 12 carbon atoms in the hydroxyalkyl radical. Particular preference is given to 2-hydroxyethyl acrylate, the isomer mixture or 4-hydroxybutyl acrylate formed in the addition of propylene oxide onto acrylic acid.

Component E

Component E is a compound which has both at least one isocyanate group and at least one ethylenic double bond in one molecule. It can advantageously be obtained by crosslinking a component D described in the preceding section with a monomeric or oligomeric polyisocyanate as described above in this application. This crosslinking is effected by the reaction of the isocyanate-reactive groups, in this case in particular a hydroxyl, amino or thiol group, and an isocyanate group of the polyisocyanate. This is preferably catalyzed by a component G, which is described later in this application. But it is also any other suitable and known in the art catalyst conceivable. Also can be completely dispensed with a catalyst.

The isocyanate group of component E may also be reversibly blocked. The reversible blocking of isocyanate groups is preferably carried out with splitter-free blocking agents.

In a further preferred embodiment, the free-radically crosslinkable building material contains blocked or unblocked NCO groups. When the NCO groups are blocked, the process of the invention further comprises the step of deblocking these NCO groups. After their deblocking they are available for further reactions.

The blocking agent is chosen so that when heated in the process according to the invention, the NCO groups deblock at least partially. Examples of blocking agents are alcohols, Lactams, oximes, malonates, alkylacetoacetates, triazoles, phenols, imidazoles, pyrazoles and amines, such as butanone oxime, diisopropylamine, 1,2,4-triazole, dimethyl-l, 2,4-triazole, imidazole, diethyl malonate, acetoacetic ester, acetone oxime, 3,5-dimethylpyrazole, ε-caprolactam, N-methyl, N-ethyl, N- (iso) propyl, Nn-butyl, N-iso-butyl, N-tert-butylbenzylamine or 1 , 1-Dimethylbenzylamine, N-alkyl-N-1,1-dimethylmethylphenylamine, adducts of benzylamine to compounds with activated double bonds such as malonic acid esters, N, N-dimethylaminopropylbenzylamine and other optionally substituted benzylamines and / or dibenzylamine containing tertiary amino groups or any mixtures of these blocking agents ,

Particularly preferred are combinations in which an oligomeric polyisocyanate based on hexamethylene diisocyanate or pentamethylene diisocyanate is combined with a component D selected from the group consisting of 2-hydroxyethyl acrylate, the mixture of isomers resulting from the addition of propylene oxide to acrylic acid and 4-hydroxybutyl acrylate.

Further preferred components E are 2-isocyanatoethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanate tri (meth) acrylate, vinyl isocyanate, allyl isocyanate and 3-isopropenyl, - dimethylbenzyl isocyanate

Component F

In principle, the free-radical polymerization of the ethylenically unsaturated compounds present in the reaction mixture can be effected by actinic radiation with sufficient energy content. This is in particular UV-VIS radiation in the wave range between 200 and 500 nm. In this case, the polymerizable composition according to the invention need not contain any component F.

However, if it is desired to dispense with the use of appropriate radiation, then the presence of at least one component F is necessary, which is suitable as an initiator of a radical polymerization of the ethylenic double bonds present in the polymerizable composition according to the invention. This component F is preferably a radiation-activated initiator.

Preferred radiation-activated initiators F are compounds of the unimolecular type (I) and of the bimolecular type (II). Suitable type (I) systems are aromatic ketone compounds, such as. As benzophenones in combination with tertiary amines, alkylbenzophenones, 4,4'-bis (dimethylamino) benzophenone (Michler's ketone), anthrone and halogenated benzophenones or mixtures of the types mentioned. Also suitable are type (II) initiators such as benzoin and its Derivatives, benzil ketals, acylphosphine oxides, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bisacylphosphine oxides, phenylglyoxylic acid esters, camphorquinone, α-aminoalkylphenones, α, α-dialkoxyacetophenones and hydroxyalkylphenones. Specific examples are lrgacur ^® (phenyl ketone, a mixture of benzophenone and (l-hydroxycyclohexyl), Messrs. Ciba, Lampertheim, DE) 500, Irgacure ^® 819 DW (Phenylbis- (2, 4, 6-trimethylbenzoyl) phosphine oxide, Fa. Ciba, Lampertheim, DE) or Esacure ^® KIP EM (oligo- [2-hydroxy-2-methyl-l- [4- (l-methylvinyl) phenyl] -propanone], Fa. Lamberti, Aldizzate, Italy) and bis ( 4-methoxybenzoyl) diethylgerman. It is also possible to use mixtures of these compounds.

Care should be taken with the photoinitiators to have sufficient reactivity with the source of radiation used. There are a variety of photoinitiators known in the market. Commercially available photoinitiators cover the wavelength range in the entire UV-VIS spectrum.

Component G

Component G is a catalyst which catalyzes the crosslinking of an isocyanate group with an isocyanate-reactive group. This is preferably a urethane group, a Thiourethangruppe or a urea group.

The polymerizable composition preferably contains a component G when a component D with at least one isocyanate-reactive group is present. However, the use of a component G also in this case is not mandatory, since the crosslinking of isocyanate groups with isocyanate-reactive groups, the trimerization catalysts used C can be accelerated and runs well without catalysis sufficiently fast, if the reaction temperature is high enough. The addition of a component G can be dispensed with in particular if the crosslinking of the isocyanate groups present in the isocyanate component A is carried out at temperatures of at least 60 ° C., preferably at least 120 ° C.

Preferred components G are the typical urethanization catalysts, as indicated, for example, in Becker / Braun, Kunststoffhandbuch Volume 7, Polyurethanes, Chapter 3.4. The catalyst used may in particular be a compound selected from the group of tertiary amines, tertiary amine salts, metal salts and organometallic compounds, preferably from the group of tin salts, tin organyls and bismuth organyls. Component H

The viscosity of the polymerizable composition according to the invention is preferably adjusted by the use of a component B in a suitable concentration. These act as reactive diluents and fundamentally make it possible to dispense with the use of additional solvents for lowering the viscosity of the isocyanate component A.

In particular embodiments, however, it may be desirable to additionally add a solvent suitable for isocyanates to the polymerizable composition according to the invention. This can e.g. be desirable if the proportion of component B in the polymerizable composition to be limited and a viscosity reduction is sought, which is not achievable with this limited proportion of component B. In this case, the polymerizable composition according to the invention may contain all solvents known to those skilled in the art for the dilution of isocyanates. These are preferably hexane, toluene, xylene, chlorobenzene, ethyl acetate, butyl acetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl or ethyl ether acetate, diethylene glycol ethyl and butyl ether acetate, propylene glycol monomethyl ether acetate, 1-methoxypropyl 2-acetate, 3-methoxy-n- butyl acetate, propylene glycol diacetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, lactones such as β-propiolactone, γ-butyrolactone, ε-caprolactone and ε-methylcaprolactone, but also solvents such as N-methylpyrrolidone and N-methylcaprolactam, 1,2-propylene carbonate, methylene chloride , Dimethyl sulfoxide, triethyl phosphate or any mixtures of such solvents.

Component I

In a preferred embodiment, the polymerizable composition according to the invention additionally comprises at least one additive I selected from the group consisting of UV stabilizers, antioxidants, mold release agents, water scavengers, slip additives, defoamers, leveling agents, rheology additives, flame retardants and pigments. These auxiliaries and additives, with the exception of the flame retardants, are usually present in an amount of at most 20% by weight, preferably at most 10% by weight and particularly preferably at most 5% by weight, based on the polymerizable composition according to the invention. Flame retardants can be present in higher dosages of up to at most 40% by weight after use.

Component J

In a particularly preferred embodiment of the present invention, the polymerizable composition contains at least one organic filler and / or at least an inorganic filler. Said fillers can be present in any shape and size known to those skilled in the art.

Preferred organic fillers are dyes and organic nanoparticles, for example based on carbon.

Preferred inorganic fillers are pigments, AlOH ₃ , CaC0 ₃ , silicon dioxide, magnesium carbonate, TiO ₂ , ZnS, minerals containing silicates, sulfates, carbonates and the like, such as magnesite, barite, mica, dolomite, kaolin, talc, clay minerals, and carbon black, boron nitride, Glass, basalt, boron, ceramics and silicic acid.

The coating composition according to the invention particularly preferably comprises at least one organic or inorganic pigment.

use

In another embodiment, the present invention relates to the use of at least one component selected from the group consisting of components B, D and E to prepare a coating composition having a ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0 to 1.0 which contains an isocyanate component A and is polymerizable both by radical polymerization and by crosslinking of isocyanate groups with one another.

Preferably, additionally at least one component B is used as defined above in this application.

All of the definitions given for the coating composition above in this application are also applicable to this embodiment. This applies in particular to the proportions of components A, B, D and E and the ratio of isocyanate groups to the total amount of isocyanate-reactive groups in the polymerizable composition.

method

In a further embodiment, the present invention relates to a process for the preparation of a coating comprising the steps of a) providing a coating composition as described above in this application;

b) applying the coating composition to a surface; c) crosslinking at least part of the ethylenic double bonds contained in said polymerizable composition; and d) crosslinking the isocyanate groups contained in said polymerizable composition; wherein first process step b), then process step c) and finally process step d) is performed.

All definitions given above for the polymerizable composition according to the invention also apply to the process according to the invention, unless otherwise stated below.

When the polymerizable composition contains at least one component D, it is preferred that the method according to the invention comprises a further process step e) in which the isocyanate-reactive group of component D is crosslinked with an isocyanate group of the isocyanate component A or a reaction product of the isocyanate component A. Said process step e) is preferably carried out after process step c). However, in most cases it will be carried out in parallel to process step e), since both the crosslinking of isocyanate groups with one another and the reaction of isocyanate groups with isocyanate-reactive groups take place at similar temperatures.

A method of making an adhesive bond comprising the steps of a) providing a coating composition as defined in earlier in this application;

b) applying the coating composition to a surface;

c) polymerizing at least part of the ethylenic double bonds contained in said polymerizable composition;

d) pressing the at least one coated surface with another surface; and

e) crosslinking of the reactive isocyanate groups contained in said polymerizable composition and the ethylenic double bonds not yet reacted in process step c); wherein the method steps c), d) and e) are carried out in any order after the method step b).

It is preferred that the method step c) before the method steps d) and e) is performed. As far as not all ethylenic double bonds have been polymerized in process step c), the unreacted double bonds are reacted in process step e).

Apply to a surface

The application of the composition according to the invention can be carried out by various methods known per se. These are preferably spraying, brushing, dipping, pouring, flooding or application by means of brushes, rollers, nozzles or doctor blades. Particularly preferred are printing technologies, in particular screen printing, Valvejet, Bubblejet and piezo printing. The surface to be coated must be adequately wetted by the composition according to the invention. The sufficient wettability of a surface is preferably defined by the maximum contact angle of the liquid on the surface being 100 °, wherein the contact angle measurement is preferably carried out by means of a Wilhelmy method tensiometer.

Preferably, the surface to be coated consists of a material selected from the group consisting of mineral substances, metal, hard plastics, flexible plastics, textiles, leather, wood, wood derivatives and paper. Mineral substances are preferably selected from the group consisting of glass, stone, ceramic materials and concrete. In a particularly preferred embodiment, these materials already exist as surfaces modified with customary organic or inorganic or hybrid paints, primers, waxes.

Crosslinking of the ethylenic double bonds

The crosslinking of the ethylenic double bonds contained in the polymerizable composition according to the invention is carried out by a free-radical polymerization. This polymerization reaction is initiated according to the invention by the use of radiation which is suitable for activating the radiation-activated initiator F. In principle, however, the use of sufficiently high-energy radiation, as defined above in this application, is sufficient for initiation of the radical polymerization in process step c), irrespective of the presence of an initiator F.

It is preferred that process step c) is carried out at most 120 and more preferably at most 30 seconds after process step b).

Crosslinking of isocyanate groups

The "crosslinking" of the isocyanate component A in process step d) is a process in which the isocyanate groups contained therein with formation of at least one structure selected from the Group consisting of uretdione, isocyanurate, allophanate, biuret, Iminooxadiazindion- and Oxadiazintrionstrukturen with each other or react with existing urethane groups. Here, the isocyanate groups originally present in the isocyanate component A are consumed. As a result of the formation of the abovementioned groups, the monomeric and oligomeric polyisocyanates contained in isocyanate component A are combined to form a polymer network.

Since a marked molar excess of isocyanate groups over isocyanate-reactive groups is present in the polymerizable composition according to the invention, the crosslinking reaction results in at most 20%, preferably at most 10%, particularly preferably at most 5%, very particularly preferably at most 2% and in particular at most 1 % of the total nitrogen content of the isocyanate component A in urethane and / or allophanate groups.

In a particularly preferred embodiment of the invention, however, the cured isocyanate component A is not completely free of urethane and allophanate groups. It therefore preferably contains at least 0.1% of urethane and / or allophanate groups, based on the total nitrogen content, taking into account the upper limits defined in the preceding paragraph.

It is preferred that the crosslinking of the isocyanate groups present in the polymerizable composition according to the invention predominantly by cyclotrimerization of at least 50%, preferably at least 60%, more preferably at least 70%, especially at least 80% and most preferably 90% of present in the isocyanate component A. free isocyanate groups to Isocyanuratstruktureinheiten takes place. Thus, in the finished material, corresponding proportions of the nitrogen originally contained in the isocyanate component A are bound in isocyanurate structures. Side reactions, especially those to uretdione, allophanate, and / or iminooxadiazinedione structures, however, usually occur and can even be used selectively, e.g. to favorably influence the glass transition temperature (Tg) of the resulting polyisocyanurate resin. However, the above-defined content of urethane and / or allophanate groups is preferably also present in this embodiment.

The crosslinking of the isocyanate groups is preferably carried out at temperatures between 50 ° C and 220 ° C, more preferably between 80 ° C and 200 ° C and even more preferably between 100 ° C and 200 ° C.

The abovementioned temperatures are maintained in process step d) until at least 50%, preferably at least 75% and even more preferably at least 90% of the free isocyanate groups present in the isocyanate component A at the beginning of process step b) are consumed. The percentage of isocyanate groups still present can be determined by comparing the content of isocyanate groups in% by weight at the beginning of process step b). present isocyanate component A with the content of isocyanate groups in wt .-% in the reaction product, for example by the aforementioned comparison of the intensity of the isocyanate at about 2270 cm-1 by means of I spectroscopy, are determined.

The exact duration of process step d) of course depends on the geometry of the workpiece to be produced, in particular the ratio of surface area and volume, since in the core of the resulting workpiece, the required temperature for the required minimum period must be achieved. The person skilled in the art can determine these parameters by simple preliminary tests.

In principle, crosslinking of the abovementioned proportions of free isocyanate groups is achieved if the abovementioned temperatures are kept for 1 minute to 4 hours. Particularly preferred is a period between 1 minute and 15 minutes at temperatures between 180 ° C and 220 ° C or a period of 5 minutes to 120 minutes at a temperature of 120 ° C.

polymer

In yet another embodiment, the present invention relates to a coating obtainable by the method described above.

A "coating" is preferably characterized by being applied to a substrate, this substrate preferably being selected from the group consisting of wood, plastic, metal, natural stone, concrete, paper and glass The coating is particularly preferably characterized in that the layer thickness is at least 0.005 mm and at most 5 mm and preferably in at least one of the other two dimensions is a dimension of at least a factor 10, particularly preferably factor 100 of the layer thickness in both the above factors are achieved in both further dimensions.

In a further embodiment, the present invention relates to at least one coating applied to at least one substrate, which is pressed between two substrates and subsequently polymerized and crosslinked and thus acts as an adhesive.

In a particular embodiment, before pressing between the two substrates of which at least one has been coated according to the invention, the at least one coating is prepolymerized by use of actinic radiation and / or heat with the aim of obtaining a stable adhesive coating according to the invention prior to compression. The following examples serve only to illustrate the invention. They are not intended to limit the scope of the claims in any way.

Examples

General Information:

Unless otherwise specified, all percentages are by weight (% by weight).

The prevailing ambient temperature of 23 ° C. at the time of the experiment is referred to as RT (room temperature).

The methods listed below for determining the corresponding parameters were used for carrying out or evaluating the examples and are also the methods for determining the parameters relevant to the invention in general.

starting compounds

Polyisocyanate A: HDI trimer (NCO functionality> 3) with an NCO content of 23.0 wt .-% of the company. Covestro AG. The viscosity is about 1200 mPa-s at 23 ° C (DIN EN ISO 3219 / A.3).

Acrylate 1: hexanediol diacrylate (HDDA) was obtained with a purity of 99% by weight from the company but GmbH or in a purity of <= 100% by weight from Sigma-Aldrich.

Acrylate 2: hydroxypropyl methacrylate (HPMA) was obtained with a purity of 98 wt .-% of Fa. GmbH, but.

Potassium acetate was obtained with a purity of> 99 wt .-% of the company. ACROS.

Lucirin TPO-L is an ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate from BASF.

Polyethylene glycol (PEG) 400 was obtained with a purity of> 99 wt .-% of the company. ACROS.

All raw materials except the catalyst and HPMA were degassed before use in a vacuum.

Preparation of the catalyst:

Potassium acetate (5.0 g) was stirred in the PEG 400 (95.0 g) at r.t. until everything was dissolved. There was thus obtained a 5 wt .-% solution of potassium acetate in PEG 400 and used without further treatment as a catalyst. Preparation of the reaction mixture

The reaction mixture was, unless otherwise indicated, by mixing polyisocyanate (A1-A2) and the acrylate / acrylates with a corresponding amount of catalyst, initiator and optionally additive at 23 ° C in a Speedmixer DAC 150.1 FVZ Fa. Hauschild 2750th min ^"1 produced.

This was then on a glass plate (tin-free side, 250 μιη) geräkelt.

In a first cross-linking step, the applied layer was treated by UV curing with a gallium-doped mercury vapor lamp and a non-doped mercury vapor lamp, both operated at 80 W / cm and at a belt speed of 5 m / min. The dose obtained under these conditions is 1400 mJ / cm ² .

After the first crosslinking step, the plate was placed upright and observed whether or not the UV-treated coating expired.

Subsequently, the coating was completely cured. For this purpose she came for 15 min at 180 ° C in a convection oven.

Test Methods

procedure

The coated plate was placed on a paper towel upright for 10 minutes and it was visually judged whether the coating was drained. Upon noticeable change in coating by placement (e.g., formation of a lower edge wasting), the coating is classified as "running off".

acetone resistance

A small cotton ball is soaked in acetone and placed on the coating surface. Each minute, the cotton ball was soaked again with acetone to compensate for the evaporation. For this purpose, the acetone was added by means of a squeeze bottle, so that the cotton ball is not moved during the Einwirkvorgangs. After 1 min and 5 min, the cotton wool impregnated with acetone is removed, the exposed area dried and immediately scraped off in order to prevent regeneration. One examines the test surface visually and by palpation by hand

Changes. It then assesses whether and what changes have occurred on the test area.

Softening or discoloration of the paint surface are assessed.

• 0 no changes detectable

• 1 swelling ring, surface hard, only visible change / trace of one

color change

• 2 swelling ring, low softening / slight color change

• 3 distinct softening (possibly slight blistering) / medium

Color change • 4 strong softening (possibly strong blistering), pierceable to the end

Underground / strong color change

• 5 coating completely destroyed without external influence / very strong

color change

hardness

Hardness is the mechanical resistance of a body to the penetration of another body. It is the quotient of the measured indentation force and the contact surface of the indenter when penetrating into the surface. The contact area is calculated with the known geometry of the indenter and the measured penetration depth.

In the instrumented penetration test (Martens hardness), the indentation force and penetration depth are measured during the deformation and thereby the elastic and plastic deformation

considered. A pyramid-shaped indenter (Vickers tip) presses with increasing test force into the coating.

A hardness value according to Martens (HM) is calculated from indentation force, penetration depth and indentor geometry.

The hardness was determined by means of Fischerscope H100C in accordance with DIN EN ISO 14577-1.

The samples are in standard climate 23 ° C and 50% rel. Humidity conditioned for at least 16h and then measured. Choice of maximum indentation force either for all samples within the

Test series equal or individual determination and setting for each sample. The setting criterion here is the bending angle, according to which the maximum indentation force is set so that the penetration depth achieved is at most 10% of the coating thickness.

The measurement result in Table 1 is the Marten hardness HM (F) in N / mm ² as the mean value of 5

Measurements indicated.

Visual assessment

After complete cure, the film was visually inspected and briefly described. EXAMPLES

The amounts of polyisocyanate, acrylate, catalyst solution indicated in Table 1 were determined according to the above mentioned. Preparation procedure for reaction mixtures treated.

The reaction mixture was 250 μιη thick geräkelt on the tin-free side of a glass plate and then with a gallium-doped and a non-doped mercury vapor lamp UV-treated as described above. Subsequently, the samples were cured at 180 ° C for 15 min in a convection oven.

Table 1: Compositions and material properties of the embodiments 1-10

All examples whose number a B projects are according to the invention. All examples whose number is preceded by a V are comparative examples and not according to the invention. Comparative Example 1 is prophetic.

All examples show a high Marten hardness HM (F) after complete curing.

Examples Bl to B5 show that after-cure films are made to be leak-resistant and homogeneous clear hard films are obtained after complete cure.

Comparative Example VI shows that the pure isocyanate forms no leakproof layer after radiation curing.

Claims

claims

A coating composition having a ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0 to 1.0 comprising a) an isocyanate component A;

b) at least one trimerization catalyst C; and

2. The composition of claim 1, comprising at least one component D or E.

3. The composition according to claim 1 or 2, comprising at least one component B.

The composition of any one of claims 1 to 3, wherein the molar ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 4.0 to 1.0.

5. The composition according to any one of claims 1 to 4, further comprising a component F, which is suitable as a radiation-activated initiator of a radical polymerization of the ethylenic double bonds present in the polymerizable composition according to the invention.

6. The composition according to any one of claims 1 to 5, wherein the proportion of components B, D and E is selected so that the coating does not proceed after radical polymerization of the ethylenic double bonds contained therein on a vertical surface.

Use of at least one component selected from the group consisting of components B, D and E for the preparation of a coating composition having a ratio of isocyanate groups to isocyanate-reactive groups of at least 2.0 to 1.0 which contains an isocyanate component A and both by radical Polymerization and polymerizable by crosslinking of isocyanate groups with each other.

8. A method for producing a coating comprising the steps of a) providing a coating composition as defined in any one of claims 1 to 6;

b) applying the coating composition to a surface;

c) crosslinking at least part of the ethylenic double bonds contained in said polymerizable composition; and d) crosslinking the isocyanate groups contained in said polymerizable composition; wherein first process step b), then process step c) and finally process step d) is performed.

9. The process according to claim 8, wherein the polymerizable composition contains at least one component D and the process comprises a further process step d) in which the isocyanate-reactive group of the component D is crosslinked with an isocyanate group of the isocyanate component A or a reaction product of the isocyanate component A. becomes.

10. The process according to claim 8 or 9, wherein in process step d) at least 50% of the free isocyanate groups present in the isocyanate component A are converted to isocyanurate structural units.

11. The method of claim 8, wherein the method step b) and c) are carried out at intervals of at most 120 seconds.

12. Coating obtainable by the method according to one of claims 8 to 11.

13. A method for producing an adhesive bond comprising the steps of a) providing a coating composition as defined in any one of claims 1 to 6;

b) applying the coating composition to a surface;

c) polymerizing at least part of the ethylenic double bonds contained in said polymerizable composition; d) pressing the at least one coated surface with another surface; and

14. Coated product obtainable by Method 8.

15 Bonded product obtainable by Method 13.