EP1115801A1

EP1115801A1 - Bonding agent hardenable by high-energy radiation and/or thermally

Info

Publication number: EP1115801A1
Application number: EP99942815A
Authority: EP
Inventors: Rainer Blum; Rodriguez Jorge Prieto; Wolfgang Reich
Original assignee: BASF Coatings GmbH
Current assignee: BASF Coatings GmbH
Priority date: 1998-08-07
Filing date: 1999-08-06
Publication date: 2001-07-18
Also published as: DE19835917A1; WO2000008108A8; US6632481B1; JP2002522588A; WO2000008108A1

Abstract

The invention relates to a bonding agent, preferably for a lacquer, which may be hardened by high-energy radiation and/or thermally and which contains a mixture of substances (a) having a monomer or polymer component including at least one vinyl ether, vinyl ester, (meth)acrylic and/or allyl group, and (b) containing saturated and/or unsaturated polymers different from component (a) as additional component, with the proviso that at least one of components (a), (b) contains structural units of general formulae (I) and/or (II) and the additional component (b) contains structural units of general formulae (I) and/or (II) at least when said component contains saturated polymers. The invention also relates to a method for the production of the bonding agent and a preparation containing the bonding agent according to the invention. Said preparation is obtained in the form of a pigmented or non-pigmented lacquer or a powder lacquer. The invention also relates to a working method for the production of lacquer coatings, wherein after application, said coatings are hardened thermally and/or by radiation with UV light or electron beams.

Description

With high-energy radiation and / or thermally curable binders

The invention relates to a binder, preferably for paints, which is curable by high-energy radiation and / or thermally, a method for its production, a preparation containing the binder and a working method relating to the preparation.

Coatings curable under UV light for use in liquid form and powder coatings are gaining more and more areas of application for reasons of solvent savings. A major problem with known UV varnishes, however, is the inhibition of curing on the surface of the varnish by atmospheric oxygen. This inhibition must be overcome by lamps with a very high energy density and an acceleration of the curing by amine coinitiators. The amines are often the cause of unpleasant smells.

With UV powder coatings, additional problems arise from the contradicting demands for good blocking resistance of the powders during storage and good flow of the melted coating film. The glass transition temperature and melting point should be as high as possible for good blocking resistance, but as low as possible for good flow and use on thermosensitive substrates in order to avoid a hardening reaction before the formation of optimal surface smoothness and damage to the substrate. To improve the surface smoothness, the melt should also have a low viscosity and only start the reaction after a delay. This It is difficult to realize ideas with powder coatings, the hardening of which is based on one of the known, thermally activated reactions between resin and hardener, for example polyepoxy resin and dicarboxylic acid hardener, because a viscosity-increasing reaction starts at the same time as the melting process. With radiation-curable powder coatings, on the other hand, it should be possible to separate the melting process and crosslinking. Various approaches have become known in the prior art for fulfilling this requirement.

US-A-4,129,488 and US-A-4,163,810 disclose UV-curable powder coatings with special spatial arrangements of ethylenically unsaturated polymers. The binder consists of an epoxy-polyester polymer in which the epoxy adduct is spatially arranged in such a way that it is spaced from the polyester adduct by means of a linear polymer chain. The polymer also contains a chemically bound photoinitiator.

EP-A 0 650 978, EP-A 0 650 979 and EP-A 0 650 985 disclose copolymers whose essential constituent is a relatively high proportion of the monomers with the structural element of methacrylic acid and which are used as binders for UV-curable powder coatings can be used. The copolymers are distinguished by a relatively narrow molecular weight distribution.

EP-A 0 410 242 discloses binders for UV-curable powder coatings which consist of polyurethanes which have certain (meth) acryloyl groups, can be crosslinked without a crosslinking component or peroxides and are therefore stable in storage. The addition of photoinitiators is required for crosslinking by means of UV radiation.

Furthermore, EP-A 0 636 669 discloses a UV-curable binder for powder coatings which consists of unsaturated polymers which may contain dicyclopentadiene and a crosslinking agent which has vinyl ether, vinyl ester or (meth) acrylic groups. DE-A 42 26 520 discloses liquid compositions which consist of unsaturated polymer in the form of unsaturated polyesters and compounds which contain (meth) acryloyl groups and / or vinyl ether groups. These compositions can be crosslinked both by means of radical images and by radiation curing and can be used as binders for paints. When crosslinking with UV radiation, it is necessary to add photo initiators.

In the case of UV lacquers according to the prior art mentioned, problems arise from the added monomeric photoinitiators and from the need to use coinitiators, generally amines, for high photosensitivity and to dub the known oxygen inhibition of the surface. The fission products of these photoinitiators remain in the hardened paintwork and are the cause of unpleasant smells.

WO 97/25724 discloses a method for coating winding and profiled wires with solvent-free polyester, polyesterimide or polyurethane resins which contain monomeric or polymeric dicyclopentadiene units.

WO 97/25157 discloses a process for coating objects with UV radiation-curable powder coatings. The binder of the powder coating materials used contains copolymers of a monomer which has at least one (meth) acrylic group and special dicyclopentadiene derivatives.

WO 97/25387 discloses the use of monomer-free saturated and unsaturated polyester resins or mixtures of saturated and unsaturated polyester resins which contain monomeric or polymeric dicyclopentadiene units as low-emission binders for coatings. And WO 97/25362 discloses the use of the same compounds as impregnating, potting and coating compositions for electrotechnical and electronic components and for Carrier materials for flat insulating materials.

Based on this prior art, the present invention had the object to provide a binder that is curable by high-energy radiation and or thermally with high reactivity and can be used preferably, but not exclusively, for paints, especially for powder paints, without An oxygen inhibition of the surface occurs, so that the use of odorous amines and other coinitiators can be dispensed with.

This object is achieved according to the invention by a binder which contains a mixture of substances which, as a component, comprise monomers or polymers which have at least one vinyl ether, vinyl ester, (meth) acrylic and / or allyl group, and (b ) contain as a further component saturated and / or unsaturated polymers different from component (a), with the proviso that at least one of components (a), (b) has unit units of the general formulas (I) and / or (H),

n = 1-10

and the further component (b) has structural units of the general formulas (I) and / or (IT) at least when it contains saturated polymers.

These binders according to the invention can surprisingly be crosslinked with high reactivity under high-energy radiation, preferably under UV light, and show no oxygen inhibition of the surface even without the use of coinitiators.

In a preferred embodiment, component (a) is made from gang compounds formed, which are selected from the group consisting of vinyl ethers of mono- and polyfurictional (poly) hydroxyl compounds, (poly) urethane vinyl ethers and vinyl ether-terminated polyesters and mixtures of two or more of these compounds.

Alternatively, component (a) can also be formed from starting compounds which are selected from the group consisting of (meth) acrylates of mono- and polyfurtional (poly) hydroxyl compounds and (poly) urethane (meth) acrylates, (meth) acrylate Terrrιirιierter polyesters, (meth) acrylate functionalized epoxy compounds and mixtures of two or more of these compounds.

In a further preferred embodiment, components (a) and / or (b) can have copolymer-bonded groups which are capable of hydrogen abstraction in the triplet-excited state. Such groups are known as Norrish π type photoiators. It is particularly advantageous in the binders according to the invention that the addition of monomeric photoinitiators can be dispensed with entirely if these copolymeric photoinitiators are present.

The binder can contain the components (a) and (b) in a ratio of 99.5: 0.5 to 0.5: 99.5. Mixing ratios of 90:10 to 10:90 are preferred, and mixing ratios of 70:30 to 30:70 are particularly preferred.

The invention also relates to a process for the preparation of the binder according to the invention, in which the components (a) and optionally (b) contain the structural units of the general formulas (I) and (H) via esters of dihydrodicyclopentadienol of the general formula (HT

with monomeric or polymeric carboxylic acids and or via esters of oligodihydrodicyclopentadienol of the general formula (IV)

n = 1 - 1 0

be introduced with mono- or polyfictional carboxylic acids.

In a preferred embodiment, the structural units of the general formulas (I) and (H) are used in components (a) and optionally (b) with the use of compounds of the general formulas (V) and / or (VI)

n = 1-10

introduced.

Compounds of the formulas (V) and (VI) are obtained via the known addition of Dicyclopentadiene (DCPD) and water on anhydrides of di- or tetracarboxylic acids, preferably on maleic anhydride. The acidity of the carboxyl groups which are adjacent to the ester groups after the addition of one mole of DCPD per anhydride is so weakened that when attempts are made to add further DCPD in portions, oligostructures according to formula (H) are formed. Oligo-DCPD mixtures are also obtained by polycycloaddition of cyclopentadiene under pressure at temperatures between 170 ° C and 300 ° C. These can be worked up by distillation. However, they are preferably reacted directly with, for example, maleic anhydride and water to give mixtures of compounds of the general formulas (V) and (VI). The esterification of this carboxylic acid with, for example, polyfurtional hydroxyl compounds leads to a component (a) according to the invention which contains residues of the maleic or fumaric acid esters.

The invention also relates to preparations which contain a binder according to the invention. The binder contained in the preparation may have been obtained in accordance with the process according to the invention. The preparation preferably consists of a pigmented or unpigmented lacquer.

The preparation can contain the binder in liquid or in solvent-free form or in the form of solutions or dispersions with suitable solvents. In addition, the preparation can contain at least one auxiliary or additive customary in paint as further constituents.

The preparation as a powder coating is particularly preferred.

The invention further relates to a method for producing lacquer coatings, in which a preparation according to the invention is applied to the surface to be coated and is cured thermally and / or by irradiation with UV light or electron beams. If the coating is carried out with a preparation in the form of a powder coating, components (a) and (b) can be solid substances which are cured thermally and / or by irradiation with UV light or electron beams. The binders can also be hardened by baking, in which case hardening catalysts or initiators can also be used. Known initiators for thermal curing are peroxides, azo compounds and CC-labile substances, for example of the pinacole type.

A considerable acceleration of the UV curing, or a lowering of the curing temperature, is possible with a combined application of heat and UV light. This makes it possible to use UV-curable powder coatings on heat-sensitive substrates such as plastic and wood. Only the surface is preferably heated by LR radiation as far as it is

Melting the powder is required. Then UV light is irradiated. The hardening by the combination of heat and UV radiation takes place so quickly that damage to the substrate can be excluded.

It is also possible to use one or more hardening mechanisms known per se in the hardening process, for example, co-crosslinking with polyfunctional isocyanates, aminoplast resins such as maleic urea or benduanamine formaldehyde resins, polyfurictional epoxies or the like. The additionally applicable crosslinking mechanisms can also be used for training purposes penetrating networks in the coatings, which often leads to the achievement of special, desirable properties, such as particularly high chemical resistance.

Examples of compounds of component (a) of the binder according to the invention are:

(Poly) urethanes, which are made in a manner known per se from polyfurictional isocyanates and are available with isocyanate-reactive substances. The unsaturated groups are incorporated by using unsaturated compounds, preferably unsaturated hydroxyl compounds, such as hydroxy-functional (meth) acrylates, such as, for example, hydroxyalkyl (meth) acrylates, hydroxycycloalkyl (meth) acrylates, hydroxy-functional vinyl esters or vinyl ethers and hydroxy-functional allyl compounds, such as, for example, allyl alcohol. The term polyurethanes is intended to include not only those compounds whose main chain is linked via urethane bonds, but also those compounds which have ester or ether chain links, ie the so-called polyester urethanes and polyether urethanes. The structural units of the general formulas (I) and / or (11) can be introduced by using, for example, dihydrodicyclopentadienol.

Compounds of component (a) which have proven advantageous are those which, in addition to the structural units of the general formulas (I) and / or (IT), contain residues of the maleic or fumaric acid esters. It is advantageous to introduce these by using compounds of the general formulas (V) and / or (VI). If, according to an embodiment of the invention, component (a) also has active structural residues of a Norrish LI-type photoinitiator, this can be introduced by using, for example, 4-hydroxybenzophenone and / or benzophenonetetracarboxylic acid compounds. If compounds which are polyfunctionally reactive with isocyanate are also used, polymers or oligomers are formed.

Preferred compounds of component (a) are those which, in addition to the structural units of the general formulas (I) and / or (LT), residues of the maleπV-fumaric acid esters and active StxTjJ residues have a photoinitiator of the Norrish LI type.

As compounds of component (a) there are also vinyl ether resins, e.g. Vinyl ether urethanes well suited, such as those in EP-A 0 505 803 and

EP-A 0 636 669 are given. In addition, vinyl ether terminated polyesters well suited, as specified in WO 89/10346. Compounds which are particularly suitable are those in which hydroxyl- and / or isocyanate-reactive benzophenone compounds, such as, for example, benzophenonecarboxylic acid anhydrides, are also used in their preparation.

Further examples of compounds of component (a) of the binder according to the invention are

(Poly) epoxides, which are made from known, preferably multifunctional, epoxy compounds, e.g. of the bisphenol-A epoxy compound type or of the bisphenol-A epoxy resin type (such as available under the brand names Epikote) by reaction with compounds that are reactive with epoxy groups. The unsaturated groups are introduced by reaction with compounds which have unsaturated groups. The (meth) acrylic acid is preferred. If such compounds of component (a) preferably have residues of maleic or fumaric acid esters, these residues can be introduced by compounds of the general formulas (V) and / or (VT). If the compounds of component (a) also have active structural residues of a photoinitiator of the Norrish LI type, they can be added via 4-hydroxybenzophenone or benzophenone tetracarboxylic acid,

Benzophenone tetracarboxylic acid anhydrides, benzophenone tetracarboxylic acid esters and benzophenone tetracarboxylic acid amides are introduced. If polyfunctionally reactive compounds or polymeric epoxy resins are also used with epoxides, polymers or oligomers are formed.

In general, compounds of component (a) can be obtained by reacting compounds which contain functional groups with unsaturated compounds which can react with them. Such compounds may also have been modified with residues of maleic or fumaric acid esters and may have active structural residues of a photo initiator of the Norrish LI type. Examples of compounds of component (a) with such a structure are polyfunctional isocyanate compounds which are reacted with hydroxyl functional unsaturated compounds or polyfunctional hydroxyl compounds which are esterified with unsaturated carboxylic acids, such as, for example, those of the general formulas (V) and (VI).

Polyacrylates as compounds of component (a) are preferably used for the production of UV powder coatings. They are obtained by copolymerization of acrylic esters and, if appropriate, further compounds which can be copolymerized with them. Structural units of the general formulas (I) and / or (H) can be introduced, for example, through the dihydrodicyclopentadienyl (meth) acrylate, dihydrodicyclopentadienyl ethacrylate and dihydrodicyclopentadienylcinnamate. If at the same time residues of the maleic or fumaric acid esters are to be contained in these compounds, these can be combined with structural units of the general formulas (I) and / or (U) via compounds copolymerizable with acrylic esters according to the general formulas (V) and / or ( VI) are introduced. Active structural residues of a Norrish LI-type photoinitiator can be introduced via aromatic or partially aromatic compounds which are copolymerizable with acrylates and which are ethylenically unsaturated before and / or after the polymerization in the triplet-excited state, for example via copolymerizable derivatives of benzophenone and such compounds as described by EP-A 0 486 897, DE-A 38 20 463 and DE-A 40 07 318 are known. These compounds are in particular those which are derived from aromatic or partially aromatic ketones or have thioxanthone structures. The active starch residues of the photoinitiator of the Norrish II type are copolymerized in component (a) in amounts of 5-80, preferably 5-30,% by weight. The proportion of these compounds which may be polymerized and capable of hydrogen abstraction is kept as low as possible, for example for cost reasons. Since they strongly influence the sensitivity of the finished binder to light, it is expedient to determine the adjusted optimum proportion individually by experiments in accordance with the intended use. The unsaturated groups are introduced in a manner known per se by polymer-analogous reaction of copolymeric reactive groups with unsaturated compounds which can react with them. Examples of these are hydroxyl-functional polyacrylates which are reacted with unsaturated isocyanates or methacrylic anhydride or are esterified with (meth) acrylic acid, carboxyl-functional polyacrylates which are reacted with unsaturated epoxy compounds, preferably glycidyl methacrylate, or are esterified with unsaturated hydroxyl compounds and epoxy-functional polyacrylates which are preferred with unsaturated carboxylic acids (Meth) acrylic acid.

These polyacrylates are preferably produced by solvent-free radical bulk polymerization in the stirred reactor, if appropriate under pressure, or particularly preferably in continuous flow reactors at temperatures above the melting temperature of the polymer formed, preferably below 140 ° C.

In this way, polyacrylates with a low molecular weight and a narrow molecular weight distribution are obtained, which is desirable in powder coatings because of the resulting narrower melting range and the lower melt viscosity. In addition, there is no need to remove an auxiliary solvent during bulk polymerization, and it is possible to incorporate pigments and coating aids directly into the melt. The very good thermal stability of the resins according to the invention is advantageous. However, the binders according to the invention also include those acrylic unsaturated polyacrylate resins which have been prepared in solvents or by the abovementioned solvent-free technology and which can be obtained, for example, by reaction of (meth) acrylic acid with copolymerized glycidyl (meth) acrylate. However, the greater sensitivity to heat during processing and powder assembly must be taken into account. The monomers or polymers to be combined are selected in accordance with the requirements placed on the UV-cured coatings. The basic principles in the selection and mixing of the corresponding monomers or polymers for adjusting the basic properties of the coatings are known to the polymer chemist and coating specialist. These requirements can be quite different. For example, the highest levels of yellowing and weather resistance, scratch resistance and gloss retention with high hardness are required for clear top coats of metallic paintwork in automobiles.

With a coil coat lacquer, i.e. A varnish, with which sheet metal sheets are coated, then wound up and later processed with deformation, depends on maximum elasticity and adhesion.

The price of the monomers or polymers can also be a selection criterion if the high quality of the coatings is not required for certain applications, but a low price is required.

In principle, the hardness, the glass transition temperature and the softening temperature of the polymers can be increased by higher proportions of "hard" monomers; e.g. Styrene or the (meth) acrylates of Cl to C3 alcohols, e.g. Butyl acrylate, ethylhexyl acrylate or tridecyl acrylate as "soft" monomers lower these properties, but improve their elasticity. It is also known that minor amounts of (meth) acrylic acid or (meth) acrylamide improve the adhesion.

The influences of the molecular weight and the molecular weight distribution, the control of the polymerization by regulator, temperature control and catalyst selection are known per se to the person skilled in the art.

Examples of components for the construction of polyacrylate resins are the esters of acrylic acid and methacrylic acid with aliphatic, cycloaliphatic, araliphatic and aromatic alcohols with 1 to 40 carbon atoms, for example: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate n-butyl (meth ) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, Tetrahydrofurfüryl (meth) acrylate, furfuryl (meth) acrylate and the esters of 3-phenyl acrylic acid, and their various isomeric forms, for example, methyl cinnamate, ethyl cinnamate, butyl cinnamate, benzyl cinnamate, Cyclohexylcinnamat, Isoamylcinnamat, Tefrahydrofürfurylcinnamat, Furfurylcinnamat, as acrylamide, methacrylamide, methylolacrylamide, methylolmethacrylamide , Acrylic acid, methacrylic acid, 3-phenylacrylic acid, hydroxyalkyl (meth) acrylates, such as ethyl glycol mono (meth) acrylate, butyl glycol mono (meth) acrylate, hexanediol mono (meth) acrylate, glycol ether (meth) acrylates, such as metho xyethylglycol mono (meth) acrylate, ethyloxyethylglycolomono (meth) acrylate, glycidyl acrylate, glycidyl methacrylate, amino (meth) acrylates such as 2-aminoethyl (meth) acrylate.

Radical copolymerizable monomers, such as styrene, 1-methylstyrene, 4-tert. Butylstyrene, 2-chlorostyrene, vinyl esters of fatty acids with 2 to 20 carbon atoms, vinyl acetate, vinyl propionate, vinyl ethers of alkanols with 2 to 20 carbon atoms, such as vinyl isobutyl ether, further vinyl chloride, vinylidene chloride, vinyl alkyl ketones, dienes, such as butadiene and isoprene, and esters of maleic and Crotonic acid. Suitable monomers are also cyclic vinyl compounds, such as vinylpyridine, 2-methyl-1-vinylimidazole, 1-vinylimidazole, 5-vinylpyrrolidone and N-vinylpyrrolidone. Monomers which are unsaturated in the allyl position can also be used, such as allyl alcohol, allyl alkyl esters, monoallyl phthalate and allyl phthalate. Acrolein, methacrolein and polymerizable isocyanates are also suitable.

Of particular importance are the monomers which contain easily abstractable hydrogen atoms. These are especially monomers with the following Groups: isoalkyl groups with 3 to 12 carbon atoms, such as isopropyl, isobutyl or ethylhexyl groups, aminoisoalkyl groups with 3 to 12 carbon atoms, such as diisopropylaminoethyl, N-isobutylisopropylaminoalkyl, cycloisoalkyl groups with 5 to 8 carbon atoms, such as methylcyclohexyl, isopropylcyclohexyl, cycloalkyl, furfuryl and tetrydrurfurfuryl groups, p-menthyl, terpin and thymol groups. Particularly suitable compounds are, for example, isobornyl acrylate, isobornyl methacrylate, isobomyl methacrylate, isobornyl cinnamate, adamantane acrylate, adamantane methacrylate, adamantane ethyl acrylate and adamantane cinnamate in the various forms of isomerism. Portions of these compounds increase the photosensitivity of the polymers.

Monomers which have other functional groups in addition to the double bond can be used for an additional thermally activatable crosslinking reaction and are then present in proportions of 1 to 60% of the monomers. As a rule, however, they are used in rather minor quantities and then improve e.g. the adhesion, the electrostatic chargeability, the flow behavior of the paints and the surface smoothness. Descendants of 3-phenylacrylic acid further improve the weather resistance of paints than built-in stabilizers. Maleic anhydride can be copolymerized in portions with (meth) acrylates and styrene, such copolymers add water and dicyclopentadiene and adducts, which are likewise to be classified under component (a) according to the invention.

Examples of compounds of component (b) of the binder according to the invention:

For the further component (b), when the binder according to the invention is used for UV powder coatings, polyacrylate resins are preferred which have structural units of the general formulas (I) and or (U) and active structural residues of a photo initiator of the Norrish LI type. By appropriate selection of the connections solid, soft or liquid Polymer settings result. They are constructed in principle as described for the polyacrylates of component (a), without the introduction of double bonds necessary for component (a). If component (b) consists of such polyacrylate resins, it is preferably combined with component (a) in the form of vinyl ethers. Particularly solid vinyl ethers such as vinyl carbazole and divinylethylene urea are suitable for UN powder coatings.

Further preferred components (b) are liquid or solid, saturated and / or unsaturated polyesters which are obtained by the polycondensation of saturated and / or unsaturated dicarboxylic acids and / or their anhydrides and polyhydric alcohols known per se. It can also be advantageous to start from the esters of the carboxylic acids and to produce the polyesters by transesterification at higher temperatures because in some cases such transesterifications are easier and faster than the direct esterification. Furthermore, poly (amide) structures can also be obtained by using multifunctional amines. The additional use of monofunctional connections is also possible, e.g. to regulate the molecular weight.

In the binder according to the invention, component (a) contains structural units of the general formulas (I) and / or (II), while component (b) does not necessarily have to contain these structural units. However, it has proven advantageous if polyesters are used as component (b) which also contain structural units of the general formulas (I) and / or (LT). The easily accessible ester-like dicyclopentadiene adducts according to formulas (ELI) and (IV) on polycarboxylic acids are preferred. The adducts of maleic anhydride and water with dicyclopentadiene according to the formulas (V) and (VI) are very easily accessible. Furthermore, the dihydrodicyclopentadienol according to formula (VLI), as indicated below, is commercially available and can also be used in the construction of the polyesters, the structural units according to general formulas (I) and / or (IL) are introduced.

According to the invention, further compounds, e.g. are used: adipic acid, cork acid, phthalic acid isomer, tetrahydrophthalic acid, endomethylene tetrahydrophthalic acid, fumaric acid, maleic acid, itaconic acid, ethylene glycol, hexylene glycol, trimethylene glycol, hexylene glycol, polypropylene glycol, polypropylene glycol A, hydrogenated bisphenol A, OH-polyfunctional polymers, such as hydroxyl group-modified polybutadienes or hydroxyl-group-containing polyurethane prepolymers and epoxy resins, polyfunctional natural products or their derivatives, such as linseed oil fatty acid, dimer and polymeric linoleic fatty acid, castor oil, castor oil fatty acid. Also important are alkoxylated OH-functional compounds, e.g. the ethoxylation and propoxylation products of the polyols mentioned.

Polyester resins into which amide or imide structures have been introduced are also suitable for component (b). The introduction of such amide or imide structures in polyester resins is known per se and is disclosed, for example, in DE 15 700273 and DE 17 200 323.

The structural units of the general formulas (I) and / or (LT) can preferably be introduced via the acidic esters according to the formulas (V) and (VI) during the polycondensation.

Oligodicyclopentadiene mixtures are obtained in a manner known per se by polycycloaddition of cyclopentadiene under pressure at temperatures between 170 ° C and 300 ° C. These can be worked up by distillation. However, they are preferably reacted directly with, for example, maleic anhydride and water to give compounds of the formulas (V) and (VI) and condensed into the polyesters of component (b).

It is also possible to prepare polyester with an excess of acid and then to react it with dicyclopentadiene. For a high turnover, the use of catalysts, such as e.g. Boron trifluoride etherate necessary. Oligodicyclopentadiene structures are also formed at higher temperatures and under pressure.

Do the polyesters contain double bonds in the polymer chain during this reaction, e.g. in the form of the maleic or fumaric acid esters, endomethylene tefrahydrophthalic acid structures according to formula (VLLI) are produced by grafting with cyclopentadiene.

Of particular importance for component (b) of the binders according to the invention are those polyesters which are obtained via hydroxy-functional allyl ethers and which are described in DE 43 21 533. These polyesters have a significantly better photosensitivity.

Also important as component (b) are those polyesters which are reacted on carboxyl groups which have remained free during the polycondensation with unsaturated epoxy compounds, preferably glycidyl (meth) acrylate. This also increases the photosensitivity. In addition, of importance as component (b) are those polyesters which contain groups which, in the triplet-excited state, are capable of abstracting hydrogen atoms and have structures of a photoinitiator of the Norrish II type. Benzophenone structures are preferred here. Benzophenone structures can be incorporated, for example, via benzophenone carboxylic acids or hydroxyl compounds of benzophenone. It has proven to be advantageous to first prepare hydroxyl-terminated polyester precursors with an excess of hydroxyl compounds and to react these with benzophenonetetracarboxylic acid dianhydride. The benzophenone structures are incorporated in the chain in the polyesters of component (b) and carboxyl groups are generated. These carboxyl groups are then preferably reacted with unsaturated epoxy compounds, preferably glycidyl (meth) acrylate.

In experiments, unsaturated polyesters as component (b), which contain units of the formulas (I) and / or (LT) together with residues of the maleic or fumaric acid esters and which contain compounds of the general formulas (IV) and / or (V) were introduced, in which further residues of the maleic or fumaric acid ester were incorporated via maleic or fumaric anhydride and which additionally had structural residues of a photoinitiator of the Norrish LI type.

As saturated polyesters of component (b), preference is given to those which, in addition to structural units of the general formulas (I) and / or (E), also have active structural residues and a photoinitiator of the Norrish LI type.

Basically, the polyester of component (b) is built up according to the special requirements such as hardness, elasticity, viscosity or softening point, which are placed on the binder according to the desired application, according to rules known to the person skilled in the art by selecting the build-up components and adjusting the Degree of condensation. The invention will be explained in more detail below with the aid of examples.

Examples

Compound 1 (preparation of a monocarboxylic acid according to the general formula (V))

In a stirred flask with heating and reflux condenser

710.81 g dicyclopentadiene 93% (5.0 mol) and 490.30 g maleic anhydride (5.0 mol)

weighed in.

The mixture is heated to 125 ° C under a gentle stream of nitrogen. Then over a dropping funnel within an hour

95.00 g water (5.0 mol + 5g)

admitted. The mixture is left to react for one hour at 125 ° C., a monocarboxylic acid of the general formula (V) being formed.

Example 1:

Production of a polyester according to component (b) with structural units of the general formulas (I) or (V), which additionally has active structural residues of a photo initiator of the Norrish II type.

In a stirring flask with heating and distillation attachment

240.00 g dicyclohexanol propane (1 mol) 236.00 g hexanediol 1, 6 (2 mol)

194.00 g of dimethyl terephthalate (1 mol) and 0.67 g of tin acetate

weighed in.

It is rapidly heated to 120 ° C. under a gentle stream of nitrogen and the temperature is then gradually increased to 190 ° C. within 3 hours, the water of condensation formed being distilled off.

The contents of the flask are cooled to 90 ° C and there are

516.80 g of compound 1 (2 mol)

98.60 g of fumaric acid (0.85 mol) 87.36 g of benzophenonetetracarboxylic acid di (ethylhexyl ester) (0.15 mol)

4.00 g dibutyltin dilaurate (DBTL) and 0.50 g hydroquinone

added.

It is quickly heated to 130 ° C. under a gentle stream of nitrogen and the

The temperature is then gradually increased to 190 ° C. in the course of 6 hours, the water of condensation formed being distilled off.

The resin obtained in this way has an acid number of 11, solidifies on cooling and, after grinding, does not give caking powder.

Example 2:

Production of a polyester according to component (b) with structural units of the general formulas (I) or (V), which additionally has active structural residues of a photo initiator of the Norrish II type. In a stirring flask with heating and distillation attachment

300.00 g triethylene glycol (2 mol) 134.00 g diethylene glycol monoethyl ether (1 mol)

516.80 g of compound 1 (2 mol)

156.60 g fumaric acid (1.35 mol) 87.36 g benzophenonetetracarboxylic acid di (ethylhexyl ester) (0.15 mol) 4.00 g dibutyltin dilaurate (DBTL) and 0.50 g hydroquinone

weighed in.

It is rapidly heated to 130 ° C. under a gentle stream of nitrogen and the temperature is then gradually increased to 190 ° C. over the course of 4.5 hours, the water of condensation formed being distilled off.

The liquid resin thus obtained has an acid number of 27 and a viscosity of 7,800 mPas / 25 ° C.

Example 3:

Production of a polyester according to component (b) with structural units of the general formulas (I) or (V)

In a stirring flask with heating and distillation attachment

300.00 g triethylene glycol (2 moles)

134.00 g diethylene glycol monoethyl ether (1 mol)

516.80 g of compound 1 (2 mol) 174.00 g fumaric acid (1.50 mol) 4.00 g dibutyltin dilaurate (DBTL) and 0.50 g hydroquinone

weighed in.

It is rapidly heated to 130 ° C. under a gentle stream of nitrogen and the temperature is then gradually increased to 190 ° C. over the course of 4.5 hours, the water of condensation formed being distilled off. The liquid resin thus obtained has an acid number of 22 and a viscosity of 2360 mPas / 25 ° C.

Example 4:

Preparation of a polyacrylate according to component (b) with structural units of the general formula I and copolymer-bound photoinitiator

In a stirred flask with heating, reflux condenser and nitrogen supply

243 g of isopropanol and

243 g toluene

weighed and heated in reflux to about 85 ° C. Then be fed through an inlet funnel within two hours

300 g dihydrodicyclopentadienyl acrylate 370 g methyl methacrylate 120 g glycidyl methacrylate 219 g butyl acrylate and 10 g mercaptoethanol

and via a second feed funnel within 2.5 hours 30 g Wako V 59 (company Wako, Azostarter) and 180 g toluene

added and postpolymerized at reflux for 2 hours. It is cooled to about 50 ° C and then

166 g of 4-hydroxybenzophenone and 1 g of dimethylarninopyridine

admitted.

The cooler is replaced by a distillation attachment and the temperature is raised to about 160 ° C. in the course of 8 hours, the solvent distilling off. A vacuum is then applied and the contents of the flask are kept at 160 ° C. for a further 2 hours. The result is a resin melt which solidifies after pouring onto an aluminum foil and, after grinding, gives non-blocking powder at 25 ° C.

The resin shows a glass transition temperature of 52 ° C and a melting temperature of 62 ° C, which was measured by DSC (Differential Scanning Colorimetry).

Example 5:

Production of a polyurethane resin with vinyl ether functions, which additionally has active structural residues of a photo initiator of the Norrish II type.

In a stirred flask with heating, reflux condenser and nitrogen feed

588.0 g 1,6-hexamethylene diisocyanate (4.5 mol) 900.0 g butyl acetate

96.7 g benzophenonetetracarboxylic acid dianhydride (0.3 mol) and 0.5 g dibutyltin dilaurate

weighed and heated with stirring and nitrogen atmosphere under reflux. Gas evolution begins, which ends after approximately 1 hour. Then at about 60 ° C within about 1 hour

118 g of hexanediol 1, 6 and

696 g 1,4-butanediol monovinyl ether (6 mol)

admitted. The reaction solution is then kept at 60 ° C. for a further 4 hours. To react the residual isocyanate, 50 g of methanol are added and stirring is continued at 60 ° C. for 2 hours. The cooler is exchanged for a still, vacuum is applied and the temperature is slowly increased to 110 ° C in order to distill off the solvent. The result is a liquid viscous resin.

Checking the examples:

To produce powder coatings, resin mixtures are prepared in a heated laboratory kneader under nitrogen at 100 ° C. by kneading, which are discharged onto aluminum foil and allowed to cool. The resins are then ground in a laboratory hammer mill and sieved to a grain size of <30 µm. The powder coatings obtained are sprinkled with a sieve onto cleaned steel sheets. The steel sheets are then placed on a temperature-controlled heating plate at a temperature of 130 ° C. and tempered for 5 minutes. The powder coating melts into a running layer, which is then irradiated with a UN quartz lamp with an emission maximum at approx. 365 nm and an energy output (measured in the level of the coating films) of 17 mW / cm for about 2 minutes. The samples are then removed from the hotplate and rubbed 30 times with an acetone-damp cotton ball approximately one hour after cooling. Liquid paints are added in a stirring flask Homogenized 50 ° C, doctored on degreased steel sheets (about 40 in the dry) and then irradiated with UV quartz lamp also with 17 mW / cm ² for about 2 minutes.

The results are shown in Table 1.

Table 1:

DVEDH = divinylethylene urea; TEGDVE = triethylene glycol divinyl ether; BDK = benzil dimethyl ketal grade values acetone strength: 0 = no attack to 5 = soluble, uncrosslinked)

The solid and liquid lacquers of the examples described here have due the binders according to the invention have good photo-crosslinkability.

Lacquer No. 5 shows a lower UV sensitivity, which is due to the fact that component (b) of the binder according to the invention has structural units of the general formula (I) and / or (IT) and residues of the maleic / fumaric acid esters, but no active structural remnants of a Norrish LT-type photoinitiator.

Claims

claims

1. Binder, preferably for paints, which is curable by high-energy radiation and / or thermally and contains a mixture of substances that

(a) as a component monomers or polymers which have at least one vinyl ether, vinyl ester, (meth) acrylic and or allyl group,

and

(b) contain as a further component saturated and / or unsaturated polymers different from component (a),

with the proviso that

at least one of the components (a), (b) has fruity units of the general formulas (I) and / or (LI), and

n = 1-10

the further component (b) has structural units of the general formulas (I) and / or (II) at least when it contains saturated polymers.

2. Binder according to claim 1, characterized in that the component (a) is formed from starting compounds which are selected from the group consisting of vinyl ethers of mono- and polyfurictional (poly) hydroxyl compounds, (poly) urethane vinyl ethers and vinyl ether-terminated polyesters and mixtures of two or more of these compounds.

3. Binder according to claim 1, characterized in that component (a) is formed from starting compounds which are selected from the group consisting of (meth) acrylates of mono- and polyfurictional (poly) hydroxyl compounds and (poly) urethane (meth ) acrylates and (meth) acrylate-terminated polyesters and (meth) acrylate-functionalized epoxy compounds and mixtures of two or more of these compounds.

4. Binder according to one of claims 1 to 3, characterized in that the components (a) and / or (b) have copolymer-bonded groups which are capable of hydrogen abstraction in the triplet-excited state.

5. Binder according to one of claims 1 to 4, characterized in that components (a) and (b) are contained in a ratio of 99.5: 0.5 to 0.5: 99.5.

6. A process for the preparation of a binder according to any one of claims 1 to 5, characterized in that in components (a) and or (b) the structural units of the general formulas (1) and (LT) via esters of dihydrodicyclopentadienol of the general formula ( ILL)

with monomeric or polymeric carboxylic acids and / or via esters of oligodihydrodicyclopentadienol of the general formula (IV)

be introduced with mono- or polyfictional carboxylic acids.

7. The method according to claim 6, characterized in that in components (a) and optionally (b) the structural units of the general formulas (I) and (LT) with the use of compounds of the general formulas (V) and / or (VI)

n = 1-10

be introduced.

8. Preparation containing a binder according to any one of claims 1 to 5.

9. A preparation according to claim 8, wherein the binder has been obtained according to the method of claim 6 or 7.

5 10. Preparation according to claim 8 or 9 in the form of a pigmented or unpigmented paint.

11. Preparation according to claim 10, which the binder in liquid or solvent-free form or in the form of solutions or dispersions

Contains 10 suitable solvents.

12. Preparation according to claim 10 or 11, which contains at least one conventional auxiliary or additive as further constituents.

15 13. Preparation according to one of claims 10 to 12 in the form of a powder coating.

14. A method for producing paint coatings, in which a preparation according to one of claims 8 to 13 is applied to the surface to be coated and is cured thermally and or by irradiation with UN light or 0 electron beams.