NL1006369C2 - Use of oxime-protected isocyanate groups in the UV curing of low-temperature resins, as well as UV-curable resins containing such oxime-protected isocyanate groups and their use in UV-curable coating compositions. - Google Patents

Description

Use of oxime-protected isocyanate groups in the UV curing of low temperature resins, as well as UV-curable resins containing such oxime-protected isocvanate greens and their use in UV-curable coating compositions.

5

The present application relates to the use of oxime-protected isocyanate groups in the curing of resins under the influence of UV radiation, in particular at low temperature, i.e. temperatures of 130 ° C or less.

The application further relates to UV curable resins bearing such oxime-protected isocyanate groups, the use of these resins in coating compositions, especially in powder coatings, and the coating compositions thus obtained.

The market for so-called powder paint compositions has grown strongly in recent years due to the many advantages that powder paints offer. For example, powder paints are environmentally friendly due to the absence of solvents and economically attractive (due to relatively low investment and operational costs), they give a good quality of the applied coatings, and they can be used for a wide variety of effects, colors, gloss grades, etc. are composed.

A drawback, however, is the high temperature at which the chemical curing reactions of commercial powder paint systems proceed (> 150 ° C). This makes the application of powder paints on, for example, wooden or plastic objects impossible, since the objects cannot withstand such temperatures. Therefore, there is a need for coating systems that can be cured quickly at a lower temperature (<110 ° C), i.e. based on chemical curing reactions that proceed rapidly at a lower temperature (<110 ° C). The object of the invention is to meet this need.

It has now been found that oxime-protected isocyanate groups can be used to impart UV-reactivity, particularly with regard to curing, to crosslinkable compounds, such as polymers, monomers incorporated into such polymers, and / or cross-linking agents.

The invention therefore relates in a first aspect to the use of an oxime-protected isocyanate group of formula I

1006369 2 - R3 - NH - CO - O - N = CR, R2 (I) wherein at least one of the groups R ,, R2 or R3 comprises or carries at least one UV absorbing group carrying the group 5 (NH - CO - O - N = C) makes it sensitive to splitting under the influence of UV radiation; in or as side chains of branched polymers or in cross-linking agents, to impart curability to these polymers or to polymeric compositions containing such polymers and / or cross-linking agents.

Preferably, in the above formula I, at least one group R or group R 2 carries or comprises the at least one UV absorbing group, or both groups R 1 and R 2 comprise and comprise at least one UV absorbing group.

The invention further relates to specific compounds, in particular polymers, monomers and / or cross-linking agents, comprising such functional groups, as well as the use of such compounds in the composition of UV-curable polymeric compositions and / or (in the case of monomers) UV cross-linkable polymers, as well as methods for cross-linking these polymers under the influence of UV radiation.

In particular, the invention relates to UV curable coating compositions obtainable by this application (s), as well as methods of curing these coating compositions under the influence of UV radiation, in particular at temperatures below 130 ° C, more in particular below 110 ° C .

Oxime-protected isocyanate groups and polymers containing such groups are known per se. They are used in the coating industry to impart thermal curability to coating compositions, especially as side fatteners in amine or hydroxyl functional resins. When the protected isocyanates are heated to temperatures of 150 ° C or more, the original isocyanate groups are reconstituted, which then cause the cross-linking reaction. The curing times depend on the nature of the oxime and isocyanate group. In addition, the course times are highly temperature-dependent. Reference is made to the following literature: US-A-4 375 539; US-A-4 596 1006369 3 744; US-A-4 997 990; US-A-4 722 969; US-A-4 824 925 (1989), EP-A-0 182 996, as well as J.S. Witzeman, Progr. Org. Coat., (1996), 27, 269 and G.B. Guise, G.N. Freeland, G.C. Smith, J. Appl. Polym. Sci., (1979), 23, 353.

It is further known to cure polymers or cross-linking agents with functional groups such as carbamate groups, formylamine groups and acyloxime groups by UV radiation. However, these are expensive specialty compounds. The oxime-protected isocyanates used according to the invention are widely used in the coating industry and can be easily and inexpensively prepared on a large scale according to conventional techniques or analogous methods.

According to the invention, it has now been found that such oxime-protected isocyanate groups can also be used for crosslinking polymers and / or curing coating compositions under the influence of UV radiation, in particular when at least one UV radiation absorbing group is present in the 15 is located near the (NH-CO-O-N = C) structural unit. It will be clear that in the prior art thermally curing compounds (polymers) such UV absorbing groups (if already present) are not present in order to sensitive the (NH - CO - 0 - N = C) - group. make for splitting under the influence of UV radiation. i.e., to impart UV-20 curability.

The UV absorbing group will usually be a group which can absorb UV radiation, i.e. electromagnetic radiation with a wavelength of 100-500 nm, in particular 200-400 nm. Such groups will be known to those skilled in the art and typically contain at least one unsaturated bond capable of absorbing UV-25 radiation.

As will be apparent to those skilled in the art, this does not necessarily require that R 1, R 2, and / or R 3 be or carry groups that are highly UV absorbing per se. It is also possible that these groups, together with the group (NH - CO -ON = C), and in particular with the (- N = C) band thereof, form a UV absorbing structural unit, whereby they form the group ( NH - CO -ON = C) susceptible to cleavage.

For example, the R 1, R 2, and / or R 3 groups may be or carry auxochromes which shift or enhance the UV absorption of the chromophore (i.e., the 1006369 4 oxime group) through interactions such as resonance. An example is acetophenone oxime, in which the phenyl and methyl groups are in themselves less strongly UV active, but in combination with the (- C = N) bond do yield a strongly UV absorbing group. Such groups or combinations thereof with the oxime-protected isocyanate group also fall within the definitions of "UV absorbing group" or the definitions of the groups R 1, R 2 and / or R 3 according to the invention.

Furthermore, according to the invention it is possible to use a separate UV-sensitizing agent ("UV-sensitizer") in combination with a compound / polymer containing oxime-protected isocyanate group (s), this UV-sensitizing agent agent makes the group (NH - CO - O - N = C) susceptible to splitting under the influence of UV radiation, whether or not in combination with UV absorbing groups present in the compound itself. This embodiment, wherein the use of a UV sensitizing compound is essentially equivalent to the introduction of UV absorbing groups into the compound / polymer itself (ie into one of the groups Rh R2 and / or R3 in Formula I) , will be discussed further below.

Preferred UV absorbing groups are: - optionally substituted unsaturated hydrocarbon residues, in particular optionally substituted alkenyl groups with 2-6 carbon atoms and optionally substituted alkynyl groups with 2-6 carbon atoms, and optionally substituted cycloalkenyl and alkylcycloalkenyl groups with a total of 4 -10 carbon atoms and preferably with 5 or 6 carbon atoms in the ring; optionally substituted aromatic groups, in particular with a total of 4-8 ring atoms selected from carbon atoms and / or optionally one or more heteroatoms O, S and N; more in particular with 4, 5 or 6 carbon atoms, optionally 1 or 2 hetero atoms, and a total of 5 or 6 ring atoms, such as phenyl, furfuryl, pyranyl, pyridinyl and the like; optionally substituted carbonyl groups with 1-10 carbon atoms, carboxyl groups, cyano groups, nitro groups, hydroxyl groups, preferably 30 cyano groups, nitro groups and / or carbonyl groups with 1-6 carbon atoms;

Furthermore, the UV absorbing group will usually be separated from the protected oxime group by at most three carbon, oxygen, nitrogen and / or sulfur atoms, especially carbon atoms; preferably by at most two of 1006369 such atoms, such as an ethyl (en) group substituted in 2 position by a UV absorbing group; more preferably by at most one further atom, such as in a methyl (en) group substituted with a UV absorbing group. The UV absorbing group can also be directly attached to the oxime-protecting isocyanate group, such as with a phenyl group.

Furthermore, in alkenyl and alkynyl groups, the unsaturated bond is preferably in the 2 position, more preferably in the 1 position; and in carbonyl and ester groups the (C = 0) bond is preferably in the 2 position, more preferably in the 1 position. Although not required, the UV absorbing group or the unsaturated bond is in the UV absorbing group preferably is positioned with respect to the protected isocyanate group such that resonance can occur between the UV absorbing group or bond and the bond (s) of the protected isocyanate group, as will be apparent to those skilled in the art. For this it is also possible that the UV-absorbing group is separated from the oxime-protected isocyanate group by a number of unsaturated bonds, heteroatoms and / or carbonyl groups, such as in a 4-position substituted with a UV-absorbing group -butadienyl group, wherein these unsaturated bonds per se can absorb UV radiation and / or can contribute to the UV absorbing capacity of the UV absorbing group and / or the group R, R2 and / or R3 as a whole, optionally in combination with the oxime-protected isocyanate group as mentioned above.

When the UV absorbing group is substituted, it may be through any substituents as mentioned below, but preferably through a substituent which itself can also absorb UV radiation, such as nitro, cyano or phenyl groups. Examples of such UV absorbing groups substituted UV absorbing groups are nitrophenyl, cyanophenyl, ethynylphenyl and the like.

Preferably, the groups R 1 and R 2 are independently selected from - hydrogen; The above UV absorbing groups, in particular cyano, nitro, 1-alkynyl groups of 2-6 carbon atoms, 1-carbonyl groups of 1-4 carbon atoms and the above-defined optionally substituted aromatic groups, in particular optionally substituted phenyl groups; 1006369 6 - optionally substituted alkyl groups of 1-10 carbon atoms, especially 1-6 carbon atoms, more particularly optionally substituted methyl, ethyl, propyl or isopropyl; - optionally substituted alkenyl groups with 2-10 carbon atoms; 5 - optionally substituted alkynyl groups of 2-10 carbon atoms - optionally substituted cycloalkyl, alkylcycloalkyl, cycloalkenyl and alkylcycloalkenyl groups with a total of 3-10 carbon atoms, and preferably 5 or 6 ring carbon atoms; - halogen (fluorine, chlorine, bromine, iodine); 10 - optionally substituted alkoxyl groups of 1-10 carbon atoms or alkoxylalkyl groups of 2-10 carbon atoms; - hydroxyl; - carboxyl; - optionally substituted ester groups with 2-10 carbon atoms; - amine groups of the formula -N T, T2, wherein T, and T2 may be hydrogen or optionally substituted alkyl of 1-10 carbon atoms, or together form a ring with at most 8 ring atoms; in particular with 3, 4 or 5 carbon atoms and optionally a further nitrogen atom in the ring; sulfhydryl and optionally substituted thioalkyl groups of 1-6 carbon atoms; Wherein preferably at least one of the groups R, or R2 comprises or carries at least one UV absorbing group, as defined above.

The R 1 or R 2 groups may also form together with the carbon atom of the oxime-protected isocyanate group to which they are attached an optionally substituted ring, such as an optionally substituted cycloalkyl or cycloalkenyl ring, optionally containing, for example, one or more heteroatoms, carbonyl groups and / or ester groups (to form a lactone ring) may be interrupted.

More preferably, the groups R 1 and R 2 are independently selected from - hydrogen; the above UV absorbing groups, in particular cyano, nitro, 1-30 alkynyl groups of 2-6 carbon atoms, 1-carbonyl groups of 1-4 carbon atoms and the above-defined optionally substituted aromatic groups, in particular optionally substituted phenyl groups; optionally substituted alkyl groups of 1-10 carbon atoms, in particular 1006369 1-4 carbon atoms, more in particular optionally substituted methyl, ethyl, propyl or isopropyl; - optionally substituted alkenyl groups with 2-10 carbon atoms; - optionally substituted alkynyl groups with 2-10 carbon atoms; 5 - optionally substituted cycloalkyl groups with a total of 4-10 carbon atoms and preferably 5 or 6 carbon atoms in the ring; wherein preferably at least one of the R, or R2 comprises or carries at least one UV absorbing group, as defined above.

Most preferably, the groups R 1 and R 2 are independently selected from 10 - the above UV absorbing groups, especially cyano, nitro, 1-alkynyl groups of 2-6 carbon atoms, 1-carbonyl groups of 1-4 carbon atoms and the above defined optionally substituted aromatic groups, especially optionally substituted phenyl groups; - optionally substituted alkyl groups with 1-6 carbon atoms, more in particular optionally substituted methyl, ethyl, propyl or isopropyl; wherein preferably at least one of the groups R, or R2 comprises or carries at least one UV absorbing group, as defined above.

The groups R 1 and R 2 may in particular be selected from cyano, nitro, an optionally substituted 1-ethynyl group, an optionally substituted phenyl group, optionally substituted methyl, ethyl or propyl groups, or substituted with one or more UV absorbing groups methyl groups.

In particular, Rt and R2 can be selected from methyl, ethyl, phenyl, methylenphenyl (-CH2-C6H5), methylenediphenyl (-CH- (C6H5) 2), nitromethyl, cyanomethyl, ethynyl, more preferably at least one of R 1 and R 2 is phenyl.

Specifically, R 1 and R 2 are both phenyl, or one of R 1 and R 2 is phenyl and the other is methyl or ethyl.

Further examples of suitable groups R 1 and / or R 2 are α-30 carbonyl groups of the general formula - (C = O) - R 4, where R 4 may be as defined above for R, and R 2, and preferably an optionally substituted alkyl group with 1-6 carbon atoms. For example, these protected isocyanates can be prepared by protecting suitable isocyanates with the mono 1006369 8 oximes of α, β-diketones of the formula

R4 - (C = 0) - CR, = N - OH

5 to form protected isocyanates of the formula R4 - (C = 0) - CR, = N - O - (C = 0) - NH -

Particularly suitable oxime-protected isocyanates are ketoximes such as, for example, benzophenonoxime, acetophenonoxime and acetonaphtonoxime.

In the present description when an alkyl, alkenyl or alkynyl group is mentioned, it can be branched or unbranched or optionally together with the atom to which it is bonded and any further groups bonded to this atom form a ring, such as an optionally substituted cycloalkyl - or cycloalkenyl ring, which can optionally be interrupted by one or more heteroatoms, carbonyl groups and / or ester groups (to form a lactone ring).

When the present description refers to an optionally substituted group or an optionally substituted carbon atom, this group or atom may, for example, be substituted with the above-mentioned UV absorbing groups and / or with one or more of the following substituents; - halogen (fluorine, chlorine, bromine, iodine); alkyl of 1-6 carbon atoms, in particular methyl, ethyl, propyl or isopropyl; - alkenyl with 2-6 carbon atoms; 25 - alkynyl of 2-6 carbon atoms; cycloalkyl, alkylcycloalkyl, cycloalkenyl, aklylcycloalkenyl, aryl, alkaryl, aralkyl with a total of 3-10 carbon atoms, and in particular with 5 or 6 ring carbon atoms, such as phenyl, cyclohexyl, 1-cyclohexenyl and methylcyclopentyl; Hydroxy, cyano, nitro, -COOH; - alkoxy of 1-6 carbon atoms; sulfhydryl and thioalkyl of 1-6 carbon atoms; - amine groups of the formula -NT | T2, wherein T, and T2 can be hydrogen or optionally 1006369 9 substituted alkyl group with 1-6 carbon atoms, or together form a ring with at most 8 ring atoms, in particular with 3,4 or 5 carbon atoms and optionally a further nitrogen atom in the ring; and the like, wherein these substituents may themselves be optionally substituted with such groups.

Furthermore, it is to be understood that where the description refers to alkyl, alkenyl, alkynyl and similar groups, they may optionally also contain or be interrupted by one or more heteroatoms S, N or O. Also, all cyclic saturated, unsaturated and aromatic carbon radicals 10 may contain one or more heteroatoms N, O and S, or in such radicals one or more carbon atoms may be replaced by such heteroatoms. Furthermore, all carbonyl groups may contain or be interrupted by a further hetero atom, such as an oxygen or nitrogen atom, optionally to form an ester or amide group.

The alkyl, alkenyl and alkynyl groups, as well as the cyclic saturated and unsaturated carbon radicals, may further contain or be interrupted by at least one carbonyl group (C = O). The alkoxy, amine and thioalkyl groups can also contain a carboxyl group, optionally to form an ester, amide or thioester bond.

Preferably, the group R3 is a linking group or bridge through which the oxime-protected isocyanate group is bonded to the crosslinkable compound, i.e., the polymer to be crosslinked, preferably a side chain or an end of the polymer to be crosslinked; a monomeric unit for the preparation of such a polymer; or (the remaining part of) the cross-linking agent, with the proviso that the oxime-protected isocyanate bond, ie the group - NH - CO - O - N = CR, R2 also directly on (the side chain or the end of the) polymer , the monomer or the (the remaining part of) the cross-linking agent may be bound. In the latter cases, the group R3 will be: - a polymeric side chain, or optionally a polymeric base chain; a monomer, a structural unit which can serve as a monomer, or a 1006369 structural unit which comprises a polymerisable group; a cross-linking agent, a structural unit which, due to the further presence of the oxime-protecting isocyanate group, can serve as a cross-linking agent, or a structural unit which contains a further cross-linking group; It will be understood that in some cases the group R3 may be part of a polymer, monomer or cross-linking agent which simultaneously serves as a linking group or bridge, especially when the group R3 is the side chain of a polymer.

When the group R3 is a linking group or bridge, it will via a further bond to the rest of the molecule, ie the polymer to be cross-linked, a monomeric unit for the preparation of such a polymer or (the remaining part of) the cross-linking agent , are connected.

The group R3 may be optionally substituted with one or more UV absorbing groups or may be interrupted by a suitable such UV absorbing residue, such as an optionally substituted aromatic residue as defined above, a carbonyl residue or an optionally substituted unsaturated hydrocarbon residue or bond .

In this case, the UV absorbing group will usually pass through no more than three (carbon or hetero) atoms; preferably no more than two atoms; more preferably, by only one further atom, are separated from the oxime-protected isocyanate group, or bonded directly to the oxime-protected isocyanate group.

Furthermore, although not required, the UV absorbing group will preferably be located relative to the protected isocyanate group such that resonance can occur between the UV absorbing group or bond and (the bond (s) of) the protected isocyanate group , as will be clear to experts. Again, the UV absorbing group can be separated from the oxime-protected isocyanate group by a number of unsaturated bonds, heteroatoms and / or carbonyl groups, as will be apparent to those skilled in the art. These unsaturated bonds, heteroatoms and / or carbonyl groups will then also form part of the R3 group and / or further contribute to the UV absorbing capacity of the UV absorbing group and / or the R3 group as a whole, possibly in combination with the (bonds of the) protected isocyanate group, as will be apparent to those skilled in the art.

1006369 11

When the group R3 is a linking group or a side chain of a polymer, it is for example: - an optionally substituted alkyl group with 1-10 carbon atoms, - an optionally substituted alkenyl group with 2-10 carbon atoms, 5 - an optionally substituted alkynyl group with 2- 10 carbon atoms, - an optionally substituted alkoxyl group with 1-10 carbon atoms or alkoxyalkyl group with 2-10 carbon atoms; an optionally substituted cycloalkyl, alkylcycloalkyl, cycloalkenyl or alkylcycloalkenyl group with a total of 3-10 carbon atoms, and preferably 5 or 6 carbon atoms in the ring; an optionally substituted aryl, alkylaryl, arylalkyl or alkylarylalkyl group with a total of 4-10 carbon atoms, and preferably 5 or 6 carbon atoms in the ring; wherein these groups may further contain or be interrupted by one or more heteroatoms S, N or O. In cyclic saturated, unsaturated and aromatic carbon residues, one or more carbon atoms can also be replaced by heteroatoms O, N or S.

The alkyl, alkenyl, alkynyl groups, as well as the cyclic saturated and unsaturated carbon radicals, may further contain or be interrupted by at least one carbonyl group - (C = 0) -20. The alkoxyl, alkoxyalkyl, amine and thioalkyl groups can also contain a carboxyl group, optionally to form an ester, amide or thioester bond.

Preferably, the group R3 is - an optionally substituted alkyl group of 1-10 carbon atoms; An optionally substituted alkenyl group with 2-10 carbon atoms; - an optionally substituted alkynyl group with 2-10 carbon atoms; - an optionally substituted alkoxyl group with 1-10 carbon atoms or alkoxyalkyl group with 2-10 carbon atoms; an optionally substituted cycloalkyl, alkylcycloalkyl, cycloalkenyl or alkylcycloalkenyl group with a total of 5-10 carbon atoms, and preferably 5 or 6 carbon atoms in the ring; - an optionally substituted aryl, alkylaryl, arylalkyl or alkylarylalkyl group with a total of 5-10 carbon atoms, and preferably with 5 or 6 carbon atoms in the ring; wherein these groups may further contain or be interrupted by one or more compounds of S, N or O.

More preferably, the group R3 is a branched or unbranched, optionally substituted alkyl group with 1-10 carbon atoms, especially with 1-6 carbon atoms, more particularly with 2-4 carbon atoms, which when it contains more than 2 carbon atoms is interrupted can be by an optionally substituted phenyl group, a carbonyl group - (C = 0) - οΓ an ester bond - O - (C = 0)

The group R3 may furthermore be, for example, an optionally substituted methyl methyl (-C122-C6II4-) or phenylmethyl group (-C6H4-CH2-) group.

The above-mentioned oxime-protected isocyanate groups can be used in virtually all types of compounds or materials that need to be UV curable and suitable applications will be apparent to those skilled in the art. The invention can be used in particular by providing these compounds with the oxime-cyclic thermo-isocyanate groups or by preparing analogs of the known compound / matrix compounds with the oxime-cyclic methyl isocyanate groups, both in a manner known per se.

Obviously, this does require that the oxime-bishermdc isocyanate groups can be suitably incorporated into the compounds, i.e., that they must be compatible with further structure and / or functional groups present in the compound.

The preparation of the oxime-isocyanate can be carried out in a manner known per se, for example by reaction of a ketoxime with an isocyanate according to the following reaction scheme:

Scheme 1: Formation of oxime-c isocyanate, R 'H 9, R' RN = C = 0 + HO-N = c '-► RNC-0-N = c' 'R "' R" where R ,, R2 and R3 are as defined above.

Hereby, use of oximes (HO - N = CR | R2) with R, and / or R, 1006369 13 groups comprising the at least one UV absorbing group offers the advantage that the compound to be cross-linked simultaneously with the formation of the oxime-protected isocyanate group, the UV absorbing group (s) can be provided in the correct position relative to the protected isocyanate group in a simple and suitable manner. In this way, also known per se compounds / polymers with oxime-protected isocyanate groups, but without UV-absorbing groups in the groups R, R2 and R3, can easily be provided with UV-absorbing groups, ie by the protected oxime present group to be replaced by an oxime (HO - N = CR, R2) with R, and / or R2 groups comprising or carrying a UV absorbing group, such as by exchange of the oxime group or by first removing the oxime group present ( deprotect) and then protect it again with oxime carrying UV groups.

The invention therefore relates in a further aspect to the use of oximes of the formula II

HO - N = CR, R2 (II) in which at least one of the groups R, and / or R2 comprises or carries a UV absorbing group as defined above, for protecting isocyanate groups in compounds, especially in polymers, to provide these compounds / polymers with UV curability as described herein.

Alternatively, UV-sensitive rendering compounds can also be used in combination with (known or not known per se) compounds / polymers with oxime-protected isocyanate groups, but without UV-absorbing groups, as further described below.

The oxime-protected isocyanate groups can be used in particular in all types of crosslinkable polymers, the groups usually being included in the side chains of the polymeric backbone. Herein can be mentioned acrylic polymers, vinyl polymers; polyolefins such as polyethylene, polypropylene and polystyrene; polyethers; polyesters; polyamides; polyimides; synthetic rubbers; polyurethanes and the like; which may contain any further functional groups known per se.

1006369 14

The oxime-protected isocyanate groups are particularly suitable as a UV crosslinking system for use in epoxy-functional polymers, as further explained below.

The polymers with the oxime-protected isocyanate groups can be prepared by using monomers which already contain oxime-protected isocyanate groups during the polymerization, or by suitably supplying already formed polymers with oxime-protected isocyanate groups, for example by side-chaining or convert the ends of the polymer bound isocyanate groups into oxime-protected groups.

The number of oxime-protected isocyanate groups in the polymer will depend on the desired application and final degree of cross-linking, but will generally be between 5-50% based on the total number of repeating units in the polymer.

The synthesis of certain polymers with oxime-protected isocyanate side groups has been described in the art, inter alia, in G. Clouet and T. Sadoun, J.M.S.-Pure Appl. chem., (1992), A29, 939. The invention can also advantageously be used for curing such per se known polymers under the influence of UV radiation, optionally after first suitably (further) UV-absorbing groups in the polymers are included.

This makes the system of economic importance, especially since oxime-protected isocyanates are already common cross-linking groups, for example in the coating industry. Activation of these known compounds / polymers by means of UV light can lead to completely different products and different cross-linking chemistry. In this way, by means of UV activation allows faster curing compared to thermal activation.

As already indicated, the oxime-protected isocyanate groups can also be incorporated into monomers, which are subsequently incorporated into a polymer by polymerization, usually with other suitable monomers.

In addition to the oxime-protected isocyanate group, such monomers will generally also comprise a polymerizable group, ie a group which allows the monomer to be incorporated into the polymeric base chain by / during the polymerization reaction, such as polymerizable acrylate groups, 1006369 ester groups, vinyl groups. , unsaturated groups (olefin and styrene groups) and the like. Here, the monomer is preferably such that the portion of the monomer to which the oxime-protected isocyanate group is bound in the final polymer forms a side chain.

It is also possible that the monomers comprise a functional group which, after polymerization, can be converted into an oxime-protected isocyanate group, such as an isocyanate group.

The oxime-protected isocyanate groups can be further incorporated into cross-linking agents. These cross-linking agents will generally comprise one or more further cross-linking groups, ie groups which allow the cross-linking agent to cross-link with the polymers to be cross-linked, in particular with functional groups on or in the side chains of these polymers. These may be known cross-linking groups, such as carboxylic acid, acid anhydride, hydroxy, phenol, isocyanate, amine, melamine or epoxy groups, or groups derived therefrom, but are preferably further oxime-protected isocyanate groups according to the invention.

Some of the compounds, especially polymers, monomers and crosslinkers of the invention are new, and form a further aspect of the invention, as discussed in more detail below.

In addition to what has already been described herein, the invention offers the following advantages, individually and / or in combination: a. Curing under the influence of UV radiation can be carried out at temperatures of less than 130 ° C, which makes the system suitable for application on temperature sensitive substrates such as wood and plastic.

25 b. The course times in response to UV irradiation, for example at 100/110 ° C, is very short compared to cure times with pure thermal activation of protected isocyanates (up to 50 times faster than pure thermal curing at 110 ° C and up to 10 times faster than thermal curing at 150 ° C) . This makes curing by UV irradiation economically attractive.

C. With these systems there is a lot of leeway in the composition of the resin used. To tune mechanical properties of the final coating, in addition to incorporating the functional groups that effect chemical curing, such as by copolymerization of APPIEM

1006369 16 and optionally GMA in a system based on, for example, acrylate resins, it is also possible to incorporate numerous other monomers, which can carry functional groups, such as other acrylate and other vinyl monomers.

d. The functional groups can be incorporated into the resin such as, for example, by random copolymerization of corresponding monomers or suitable derivatization of the side chain, that a homogeneous distribution of these groups is ensured, so that the curing reaction takes place more efficiently.

e. Because the protected isocyanate groups are already coupled to the resin, curing takes place more effectively. This is explained by the fact that UV protected irradiation never converts all protected isocyanate groups.

I.g.v. This means that a large percentage of the crosslinker does not contribute to the curing reaction because bifunctional low molecular weight photolinkers (as used in the lithography) do not use both crosslinker molecules with no and only one converted photogroup.

f. The system, in particular the copolymer of APPIEM with methyl methacrylate, can be used, for example, in powder coatings together with epoxy-functional resins. There is a wide choice of commercially available epoxy-acrylate resins and epoxies based on, for example, polyester or bisphenol resins, which makes the applicability of, for example, poly (MMA-co-APPIEM) very great.

g. The starting materials are relatively inexpensive and the synthesis and further reactions required for the application of the invention are easy to carry out.

h. Without UV irradiation, the resin can be kept at an elevated temperature, such as about 100 ° C, for some time, such as 15 minutes, without cross-linking. This means that the resin is suitable as a powder coating resin, where extrusion takes place at approx. 100 ° C during production (residence time in extruder ± 2 min).

The oxime-protected isocyanate groups according to the invention, the polymers and cross-linking agents with these groups, polymeric mixtures containing such polymers and / or cross-linking agents, as well as the curing of such polymers or polymeric mixtures under the influence of UV radiation, can suitable purpose. For example, the invention can be used in the manufacture of plastic objects such as films by means of UV curing; use in photolithography, including making photoresist coatings, and the like.

These are in particular applications in which curing under the influence of UV radiation can be suitably applied. This means, among other things, that the polymer and the polymer mixture must be resistant to the UV radiation to be used and that the UV radiation must be able to penetrate into the polymer mixture in such a way that all oxime-protected isocyanate groups can be cross-linked to the desired extent. . The person skilled in the art will be able to determine the correct conditions (wavelength, duration, intensity, etc.) for the UV curing on the basis of the present description, possibly after a number of simple preliminary tests.

The invention is suitable, for example, for the curing of polymers or polymeric mixtures which, because of their properties, cannot or cannot be cured at high (er) temperatures, for instance because of aging, discoloration or other deterioration in the desired properties of the polymer or polymeric mixture, or because it is not possible to obtain the desired properties in the final product at such temperatures. According to the invention analogs of these known polymers or polymeric mixtures will be used, which are provided with oxime-protected isocyanate groups according to the invention and which are subsequently cured under the influence of UV radiation. Also, cross-linking agents with oxime-protected isocyanate groups according to the invention can simply be used with these polymers or in these polymeric mixtures.

The polymeric mixtures according to the invention can further be formulated in a manner known per se, ie by using known additives in amounts known per se. The polymers with the cross-linking groups and / or the cross-linking agents according to the invention can also be used in amounts known per se, for example 20-30, 100 wt. % of the polymer or 5-50 wt. % of the cross-linking agent, based on the total composition.

It is of course required here that the oxime-protected isocyanate groups be compatible with the other components of the mixture, in particular 1006369 18 functional groups which may be present thereon, and that after UV irradiation a cross-reaction can be initiated with the desired constituents in the mixture.

The invention is particularly suitable for manufacturing coating compositions and curing these compositions on substrates 5 by UV irradiation to form a coating (beat) on the substrate. Here, the invention can be applied to all known polymeric coating compositions, including waterborne systems, organic solventborne systems, oil based systems, alkyd resins, photoresists, latices, and the like, as well as the further systems listed below.

The invention can be used herein with all types of base polymers for coating compositions, such as acrylic polymers, vinyl polymers, epoxies, polyurethanes, and polyesters, to impart UV curability to these polymers, especially where these polymers have hitherto been treated by other means, such as thermally cured, or as an alternative to UV sensitive cross-linking groups already used in such polymers, such as the aforementioned carbamate, formylamine and acyloxy groups.

These coating compositions can further be formulated in a manner known per se, that is to say by using known additives for coating compositions in amounts known per se, for which reference is made to the known manuals. The polymers and / or cross-linking agents according to the invention can be used in amounts known per se, for example 20-100% by weight of the polymer or 5-50% by weight of the cross-linking agent, based on the total coating composition.

Curing is carried out by applying the coating to the substrate to be coated and then exposing it to UV radiation of an appropriate wavelength and intensity. The suitable wavelength will mainly depend on the UV absorbing groups present, but it is in particular in the range of 200-400 nm. Here, the final degree of cross-linking can optionally be controlled on the basis of the duration and / or the intensity of the irradiation. As a rule, the coating will be irradiated within 1 hour, preferably less than 20 minutes of irradiation, preferably within 1 second to 10 minutes of irradiation, and fully cured.

1006369 19

It is optionally possible to use oxime-protected isocyanate groups with different UV absorbing groups (ie sensitive to UV radiation with 5 different wavelengths) in a polymer mixture (ie in different components of the mixture or even in the same compound on the same polymer). ) which can then be cross-linked simultaneously or separately by simultaneous or sequential exposure to UV radiation at the appropriate specific wavelengths.

The coating compositions of the invention can be applied to any substrate to which the coating composition (after curing) 10 adheres adequately and which is compatible with the coating composition. As already mentioned, the cross-linking system of the invention hereby offers the great advantage that the UV-curing can be carried out at temperatures below 130 ° C, more in particular below 110 ° C, which makes the coating compositions according to the invention particularly suitable for application to temperature sensitive substrates, such as wood or temperature sensitive plastics such as thermoplastics.

In this way, the invention makes it possible to use known coating compositions with oxime-protected isocyanate groups on such substrates, where hitherto this has not been possible due to the temperature required for thermal curing.

The invention is particularly suitable for use in systems that contain little or no solvent, such as high-solid paints, and more particularly for use in powder coatings, as further explained below.

This is generally understood to mean thermoplastic and / or duromeric plastics, which are applied in powder form on the substrate to be coated.

Such powder coatings can be formulated on the basis of various types of polymers, including acrylate resins, epoxy resins, epoxy acrylate resins, polyester resins, epoxy / polyester and polyurethane resins, and the like. The invention can be used in all these known types of powder coatings, in particular with acrylate resins, epoxide resins and epoxy acrylate resins. Although the system is self-curing, and thus can form hard coatings without further additives, it will be economically advantageous to use the system as a curing agent for epoxy-functional resins. Because these epoxy resins (based on acrylate, bisphenol-A or polyester) form one of the largest market segments within the 1006369 powder coating market, the invention is widely applicable.

The powder coatings may further contain any known powder coating additives in amounts known per se, such as fillers, pigments and dyes, flow improvers, catalysts, effects (e.g. 5 for obtaining metallic appearance) and the like.

The powder coatings of the invention can be formulated in a manner known per se, usually by mixing the above ingredients in the above amounts.

The powder coatings thus obtained can then be applied to the substrate in any manner known per se, for example by hand application (sprinkling); by means of electrostatic techniques such as electrostatic spraying (corona or tribo spraying), by fluidized bed sintering (electrostatic or not) and then curing for a suitable time by exposure to UV radiation of a suitable wavelength and intensity.

The coating thus applied can have any desired thickness, as a rule usual thicknesses for coatings based on powder coatings such as 1-4000 μτη, preferably 20-400 μτη.

As mentioned, a number of polymers, monomers and cross-linking agents of the invention are new compounds.

20 This concerns in particular polymers that are repeating structural units

containing the general formula III

-f Rs - * - 25 | R3 - NH - CO - O - N = CR, R2 (III) where R1, R2, and R3 are as defined above, and R5 is a repeating unit of the polymeric backbone derived from polymerization monomer used, for example an optionally substituted olefin, vinyl, ester or urethane unit.

In particular, R5 is an optionally substituted acrylate or methacrylate unit and R3 is an optionally substituted alkyl bridge with 1-10 carbon atoms, especially 2-6 carbon atoms. Such structure units 1006369 21 have the general formula IV: -KHrCRe * - ii 5 C = 0 (IV) 0 - (CH2) - - NH - CO - 0 - N = CR, R2 10 where η 1 to 10, preferably 2 -6; and R * is hydrogen or methyl.

The polymer may comprise further suitable repeating base chain structural units in appropriate / desired amounts based on the total number of monomer units. These further structural units may optionally comprise functional groups known per se, especially in their side chains, for imparting desirable properties to the polymer, and are preferably derived from the same type of monomer as the structural unit of formula III or IV. As a rule, these further structural units will be derived from monomers known per se.

The polymers according to the invention can here be both random copolymers and copolymers with a specific, predetermined order of the monomer units, depending on the monomer units used and the method of preparation / polymerization.

A special class of polymers according to the invention are copolymers based on acrylate or methacrylate units, which contain the oxime-protected isocyanate groups according to the invention in the side chain, in particular those acrylic copolymers which also contain side chains with epoxy-functional groups, with which the oxime -protected isocyanate groups can initiate a cross-linking reaction. These polymers are generally composed of the following structural units, among others: 1006369 22 -ίοΗ2-ΗΜοΗ2-Γ-! 4; Κ-Γ- ^ Γ Γ t °

CH3 CH2 CH

oV

NH U'ch2 c = o o 10 t @% Η3

The invention further relates to monomers for the preparation of the above-mentioned polymers. These are generally monomers of the general formula V.

R7 20! (V) R3 - NH - CO - O - N = CR, R2 in which R1, R2 and R3 have the above meanings and R7 is a polymerizable group as defined above, such as an alkenyl group, vinyl group or ester group, or a monomeric structural unit bearing such a polymerizable group.

In particular, R7 is an optionally substituted acrylate or methacrylate unit and R3 is an optionally substituted alkyl bridge with 1-10 carbon atoms, especially 2-6 carbon atoms. Such structure units have the general formula VI: 1006369 23 ch2 = cr * 5 C = 0 0 (VI) (CH2) n - NH - CO - O - N = CR, R2 10 where R ,, R2 and R3 have the above meanings , η is 1 to 10, preferably 2-6; and R1 is hydrogen or methyl.

The invention further relates to a process for the production of polymers and copolymers, in particular by polymerization in a manner known per se, using the above-mentioned monomers, as well as the polymers thus obtained. Here, the amount of oxime-protected isocyanate groups can be easily controlled by the amount of the corresponding monomer (ie, with the oxime-protected isocyanate group or a precursor thereof) included in the polymerization starting mixture.

Finally, the invention relates to cross-linking agents containing at least one oxime-protected isocyanate group according to the invention, and at least one further cross-linking group as described above.

The cross-linking agents according to the invention have the general formula Vil R8 - R3 - NH - CO - O - N = CR, R2 (VII), where R, R2 and R3 are as defined above, and Rg is the further cross-linking group, or a structural unit carrying a further cross-linking group. This further cross-linking group Rg is preferably a second oxime-protected isocyanate group.

The group R3 is preferably an optionally substituted linking alkyl group. Such cross-linking compounds with two oxime-protected 1006369 24

isocyanate groups have the general formula VIII

NH - CO - O - N = CR, R2

5 I

(CH2) „I (VIII)

R, R 2 C = N - O - CO - NH

10 wherein R, / R |, R2 / R2 and R3 are as defined above wherein η is 1 to 10, preferably 4 to 6.

Here, R, R, and R 2 and R 2 are preferably all phenyl, or R, R, both 15 and R 2 and R 2 are both methyl. Examples of such cross-linking agents are: c6h5 ^ "c6h5 C = N-0-C0-NH- (CH2) n-NH-C0-0-N = C 20 C6H 'n C6H5 C6H5 ^ x C6H5

C = N-O-CO-NH- (CH2) n-NH-CO-O-N = C

Me y s Me

These cross-linking agents can be incorporated in appropriate proportions into polymers with cross-linkable functional groups, including coating compositions such as commercially available epoxy resins, after which these compositions can then be cured by exposure to UV radiation.

The invention further relates to cured polymeric articles, in particular cured coatings, obtained by UV-curing polymeric compositions comprising compounds with the oxime-protected isocyanates of the invention. The invention also relates to substrates provided with such a coating.

These articles and coatings will generally be distinguished from articles and coatings obtained by thermal curing of the same 1006369 starting materials (polymers), in particular in that the UV curing will usually proceed according to other cactic mechanisms, resulting in other cliclic products. / or another structure of the cured product.

Although the invention is not particularly limited, it is believed that the UV-radiation radiation according to the invention proceeds via at least one of the following mechanisms, or a combination thereof: - formation of nmradradicals; - formation of free primary amines; - formation of hydrazines.

CO2 lock / climates of CO2 in which free amines, hydrazines or radicals can be formed which can form a linkage with further functional groups present, such as coxoxy functional groups. In this way, a system can be fully cured around 1 () () ° C within a few minutes.

The chemistry behind the UV ractics of oxime-bcsehcrmdc isocyanalcne is complicated by the many possible reactions that can occur. The UV-rcactic is probably analogous to UV-rcactics of carbamatcn and aeyloximes:

Scheme 2: Supposed mechanism of UV-rcactic of oximc-bcschcrmdc 20 isocyanalcn | Ri IN * + * N = C 1 -ANN = C Rl INC-0-N = C - ^ co2 * H R2 * H R2 HO R2 v 25 \ An · Διλ Λ ί '\ I — nh2 f — nh-nii2 IJ *,%

-N = C = 0 + HO-N = C

R2 30

Metigation of the original isocyanal by heat treatment is used in commercial systems. However, hydrazines or amines are formed by UV radiation. The hydrolyscstnp resulting in a 100 6369 26 hydrazine already passes through small traces of water in the system. Therefore, adding extra water to the system is generally not necessary.

The self-ow curing of resins containing protected isocyanal groups can be explained in various ways. During UV irradiation at 100 ° C, most of the groups of tol amines or hydrazines will disintegrate. However, a smaller proportion will react to isocyanate due to the elevated temperature and may couple with amine or hydrazine groups (Scheme 3). During a thermal cure, only isocyanate groups will be formed, which can react with a protected isocyanate group (Scheme 4). Less likely, but possible in principle, is the cross-linking of resin chains by recombination of radicals generated under UV irradiation (Scheme 5).

Scheme 3: Self-owl curing, reaction of a hydrazine with an isocyanate, analogous to aminc-isoeyanal ractic 15 t i I H O H t t-NH-NH2 + 0 = C = N-1 -► I-NH-N-C-N-1

Scheme 4: Self-owl curing, reaction of an isocyanate with an oxime-bcschcrmdc 20 isocyanate

Ir OH

, K1 · μ t -N = C = 0 + C = N-0-C-N-j r2 'i R1. ° i 25 C = N-0-C-N-1 * 2 '0 = C *

N-H

tVVVVTVYV »

Scheme 5: Self-curing, recombinatic of radicals 30 * Η Η! n f 3-N + + Ν-1 -f-N-N-1 i ί H * 1006369 27

The reaction of amines or hydrazines formed with epoxy groups is well known (Scheme 6).

Scheme 6: Reaction of an amine group with epoxy groups

5 O

/ \ v.v.vv CH CH2 H2N w *.

OH

10 y .-. Www CH CH2 NH '‘w o Λ \ ν \\ CII CMj

T

OH

v / .vwwA CH CHj N

15 9h2

HO CH

l;

Hydrazines are more reactive to esters than amines. It is therefore good to imagine that ester groups in the resin are attacked by hydrazines, which can lead to cross-linking:

Scheme 7: Reaction between a hydrazine and a methacrylate group? O | > o <I — nh-nh2 * H3C-0-C-I -► I-NH-NH-C j 25 f ïi |

In principle, the radical intermediates during the UV reaction also offer the possibility of cross-linking of resins containing double bonds. This may explain the curing of poly (MMA-co-APPlEM) / Viaktin VAN 1743 mixtures. A radical generated by UV light can attack a double bond and effect coupling of double bonds (Scheme 8).

1006369 28

Scheme 8: Cross-linking of unsaturated resins by free-radical mechanisms. M f * II C

N-N. + ÏÏ -► 1-N-C wCrC ^ - »> NETTING

5 C I i

In addition, amines or hydrazines can also add to double bonds: 10 Scheme 9: Reaction of a hydrazine with a double bond # i t i cl h

-NI 1-NI 12 +, r - ► I-NH-NII-CH

c i i 15

The reaction with amines is analogous.

However, other variants are also possible, for example: UV-ow curing of a mixture of 2 resins consisting of a resin with coxy side groups and a resin 20 with protected isocyanate side groups, or UV curing of a low molecular weight cpoxy-lunctionccl resin. vemctlcr containing multiple protected isocyanate groups:

Compounds containing kloximc-bcschcrmdc isocyanate groups can crosslink epoxy-functional resins by proper selection of the ketoxime under the influence of UV-radiation. The oxime-bcschcrmdc isocyanate group must absorb UV light in the correct range (200-300 nm). This is achieved with ketoximes such as benzophenonoxime, acctophcnonoximc and acclonaphtonoximc.

The oxime-isocyanate groups can be incorporated into a resin as a side chain, optionally together with polyoxy side groups. However, the use of low molecular weight compounds with protected isocyanate groups is also possible.

The system is interesting from an economic point of view, especially since oximc-bcschrmdc isocyanatcn are already common groups in the contingindustric. However, 1006369 29 are only thermally activated. Activation by UV light leads to completely different products and different cross-linking chemistry. In this way, by means of UV activation allows faster curing compared to thermal activation. The choice of oxime is decisive for an efficient UV reaction.

The oxime-protected isocyanate group must show good absorption of UV light between about 200 and 300 nm, since lamps with light in this range are generally used. UV-active protected isocyanates can be realized, for example, with acetophenone, benzophenone or acetoneaphtonoxime. However, it is likely that isocyanates protected with UV inactive oximes (eg 10 MEK, or acetone oxime) in the presence of a suitable sensitizer (eg benzophenone) are still capable of UV reaction.

According to a further embodiment of the invention, it is also possible not to include the UV absorbing groups in the same compound as the oxime-protected isocyanate group (ie in one of the groups R 1, R 2 or R 3), but a compound having a oxime-protected isocyanate group with at least one further compound which makes the group (NH - CO - O - N = C) susceptible to splitting under the influence of UV radiation.

This can be done, for example, by including such UV activating compounds ("UV sensitizers") in appropriate amounts in a polymer composition having oxime-protected isocyanate groups in the side chain, and then the compositions thus obtained under the influence of UV - curing radiation in a manner known per se.

This embodiment can be applied to all compounds with oxime-protected isocyanate groups, such as those in which R 1, R 2 and / or R 3 have the meanings given above, but without the (further) presence of a further UV-absorbing group in a of the groups R 1, R 2 and / or R 3 is required.

This embodiment is particularly suitable for use in known polymers with oxime-protected isocyanate groups, which furthermore contain no or only weak UV-absorbing groups in the vicinity of the (NH - CO - O - N = C) structural unit. It will be appreciated by those skilled in the art that the use of a UV sensitizing compound in combination with such a polymer is essentially equivalent to introducing UV absorbing groups into this polymer itself, ie, into one of the R groups. R2 and / or R3 as described above.

In principle, all per se known UV sensitizing agents can be used, such as the sensitizers which are already used in known UV systems based on carbamate groups, formylamine groups and acyloxime groups, such as benzophenone. The person skilled in the art will be able to determine by simple tests which UV sensitizing agent is suitable for use with a specific oxime-protected isocyanate compound, as well as what conditions are suitable for this particular combination (such as concentration / amount of the sensitizing the wavelength to be used, the intensity and the irradiation duration). For example, benzophenone can be used as a sensitizer with, for example, isocyanates protected as aliphatic oxime, such as acetone oximes or MEK oximes.

The invention will now be elucidated by means of the non-limiting examples below, as well as by means of the figures, which show the results of curing tests of oxime-protected isocyanates under the influence of UFV radiation according to the invention.

Example 1: Synthesis of low molecular weight oxime-protected isocyanate crosslinkers 20

Acetophenonoxime was obtained by refluxing a solution of 23.3 mL acetophenone, 16.1 mL pyridine, 13.9 g hydroxylamine hydrochloride in 200 mL ethanol overnight. The solution was then evaporated to about 50 mL and poured into demineralized water. The solid product was recrystallized 2 times from water / methanol.

9.4 g of acetophenonoxime and a catalytic amount of triethylamine were dissolved in 65 mL of dry toluene. 5 mL of hexamethylene diisocyanate was added slowly while the solution was stirred vigorously under N2. The solution turned cloudy white. After stirring at room temperature for 1 hour, the solution was stirred at 80 ° C for an additional 5 hours. The solution was evaporated and the crude product recrystallized from dichloromethane / toluene.

1006369 31

Example 2: Synthesis of resins with oxime-protected isocyanate side groups

Acrylic resin with oxime-protected isocyanate side groups, poly (MMA-co-APPIEM): 2.8 g of acetophenone oxime (see 2.1) and a catalytic amount of dibutyltin dilaurate were dissolved in 15 mL of dry toluene. 3 mL of 2-isocyanatoethyl methacylate was added dropwise slowly and the solution was stirred at 60 ° C under nitrogen for 3 hours. After 3 hours, 0.5 mL of glycidyl isopropyl ether was added and the solution was stirred for an additional 30 minutes to allow any aminomethacrylates to react.

9 mL of the solution was added to a solution of 13.5 mL of methacrylate in 50 mL of dry toluene. 0.16 g of AIBN was added and the solution was degassed by purging dry nitrogen. The polymerization was carried out by stirring at 70 ° C overnight. The polymer solution was concentrated and precipitation of the product took place in n-hexane. After drying in vacuo at 30 ° C, a quantitative yield was obtained.

Example 3: Synthesis of acrylic resin with both epoxy and oxime-protected isocyanate groups, poly (MMA-co-GMA-co-APPIEM).

The synthesis was carried out analogously to Example 2, but glycidyl methacrylate was also added before the polymerization.

Example 4: Characterization of Synthesized Polymers. The polymers of the invention were analyzed for composition by 1 H-NMR. Table 1 lists the percentages of functional monomer units in the polymers.

1006369 32 TABLE 1

Theoretical polymer compositions (based on added monomer ratios) compared to the using H-NMR certain compositions

Polymer% GM-% GM% AP-% APPIE-

Ath Ade. PIEL * Mdet

Poly (MMA-co-GMAlO) 10.8 12.8

Poly (MMA-co-GMA30) 32.8 36.2

Poly (MMA-co-GMA65) 64.9 - PGMA 100 100

Poly (MMA-co-APPIEMlO) - - 7.4 7.7

Poly (MMA-co-GMA30-co- 22.7 21.3 19.6 18.5 APPIEM30)

The molecular weights of the copolymers were determined using gel permeation chromatography in chloroform, using polystyrene calibration curves. Table 2 provides an overview.

1006369 33 TABLE 2

Molecular weights of the copolymers, measured by G.P.C. in chloroform. Calculation of molecular weights using polystyrene calibration curves

Polymer Mn Mw Mw / Mn

Poly (MM A-co-GM A10) 11200 21800 1.9

Poly (MMA-co-GMA30) 3600 6400 1.8

Poly (MMA-co-GMA65) 4000 9400 2.4

Poly (MMA-co-APPIEMlO) 28000 70000 2.5

Poly (MMA-co-GMA30-co- 20800 35000 1.7 APPIEM30)

Example 5: UV curing of epoxy functional resins using low molecular weight oxime-protected isocyanate compounds

Acrylic resins with varying percentages of glycidyl methacrylate, poly (MMA-co-GMA) were cross-linked with acetophenonoxime-protected hexamethylene diisocyanate (AOPDIC). In Figure 1, showing the insoluble fraction as a function of epoxy content in acrylic resin for poly (MM A-co-GM A) with 0.3 moles AOPDIC / mole epoxy groups, under UV irradiation at 100 ° C for 10 minutes and post cure at 90 minutes 120 ° C, the results are shown. The best results were obtained with acrylate resins with higher epoxy contents (> 50 mol%), where a reasonable degree of cross-linking could be observed.

1006369 34

Example 6: Cross-linking with acrylate resins with oxime-protected isocyanate side groups, poly (MMA-co-APPIEM10) / Self-sealing of poly (MMA-co-APPIEM10)

PoIy (MMA-co-APPIEMlO) can be cured without further additives. Reference is made to Figure 2, which shows the results of self-cross-linking, for poly (MMA-co-APPIEM10), by UV irradiation at 100 ° C and (for comparison) thermal at 120 ° C.

Figure 2 shows that poly (MMA-co-APPIEM10) can be fully cured at 100 ° C within minutes. Thermal curing is also possible but is slower 10 even at higher temperature (120 ° C).

Example 7: Curing of poly (MMA-co-APPIEMlO) with triglycidyl isocyanurate (TGIC)

Films of poly (MMA-co-APPIEMlO) with 7.5% by weight TGIC were cured under UV irradiation as well as purely thermally. Reference is made to Figure 3, which shows the results for curing poly (MMA-co-APPIEM10) with 7.5% by weight TGIC, by UV irradiation at 100 ° C or (for comparison) thermally at 120 ° C.

Figure 3 shows that UV curing in the presence of TGIC is faster than UV curing of pure poly (MMA-co-APPIEMlO) as shown in Figure 2. 20 Furthermore, in the presence of TGIC, an induction period is observed when the system is thermally cured .

Example 8: Curing of poly (MMA-co-APPIEM10) with poly (MMA-co-GMA65)

Mixtures of poly (MMA-co-APPIEM10) / poly (MMA-co-GMA65) (1/1) were cured both thermally and with UV irradiation. Reference is made to 1006369 Figure 4, which shows the results for curing poly (MMA-co-APPIEM10) / poly (MMA-co-GMA65), by UV irradiation at 100 ° C or thermally at 120 ° C.

Curing of mixtures of poly (MMA-co-APPIEMlO) and poly (MMA-co-5 GMA65) is slower in both UV and thermal curing than when poly (MMA-co-APPIEMlO) cured with TGIC or without further additives is going to be. This can probably be attributed to the lesser degree of homogeneity of these films. Nevertheless, relatively fast curing is observed, especially with UV irradiation. The thermal curing curve again shows an induction period, as can also be observed with the TGIC-containing system.

Example 9: Curing of poly (MMA-co-APPIEMlO) with an unsaturated polyester resin

Because it is plausible that the oxime-protected isocyanate reaction is also possible.

UV light travels through radical intermediates, it was tested whether mixtures of poly (MMA-co-APPIEM10) with an unsaturated polyester resin were cured. The radicals generated can in principle initiate a polymerization of the unsaturated system. Viaktin VAN 1743 (Vianova Resins, Hoechst) was chosen as the polyester resin. The results are shown in Figure 5 for curing poly (MMA-co-APPIEM10) / Viaktin VAN 1743 mixtures as a function of the composition, under UV irradiation at 100 ° C for 4 minutes and post-cure at 100 ° C for 1 hour.

Figure 5 shows that Viaktin VAN 1743 does not cure properly under the imposed conditions without further additives. However, an improved cure is obtained by the presence of poly (MMA-co-APPIEM10). The highest degree of curing is found in films containing 70% by weight poly (MMA-co-APPIEM10). The optimum in the graph shows that the unsaturated polyester resin actually participates in the curing reaction and is not inert.

1006369 36

Example 10: Crosslinking with acrylic resins with oxime-protected isocyanate side groups and epoxy side groups, poly (MMA-co-GMA30-co-APPIEM30)

When both oxime-protected isocyanate groups and epoxy groups are incorporated in an acrylate resin, a very efficient curing reaction can be expected, for instance by UV irradiation, because the functional groups are distributed very homogeneously throughout the resin. Reference is made to Figure 6 which shows the results of UV curing of poly (MMA-co-GMA30-co-APPIEM30) as a function of UV irradiation time at 100 ° C.

Indeed, as can be seen in Figure 6, the UV curing reaction is faster than commonly observed with poly (MMA-co-APPIEM10). Almost complete curing takes place within 1 minute. Too long UV irradiation apparently leads to poorer film properties (overcure).

The thermal curing behavior was also investigated for poly (MMA-co-GMA30-co-APPIEM30). Reference is made to Figure 7, which shows the insoluble fraction of poly (MMA-co-GMA30-co-APPIEM30) as a function of temperature, under curing for 15 minutes.

Figure 7 shows that no significant reaction occurs below 100 ° C within 15 minutes. Around 120 ° C, the curve rises rapidly and the system begins to cure thermally.

Example 11: Applying a coating under the influence of UV cross-linking.

a. Film formation:

A solution of the respective resin with optional coreagents was made in chloroform or methylene chloride (40 mg solid per mL). Glass slides (25x25 mm or 26x76 mm) were cleaned with an alcoholic solution and washed with demineralized water. After drying, polymer solution was dripped onto the plates and the solvent evaporated. The resulting thin films 1006369 37 (± 60 µl) were dried in an air-flow oven at 40 ° C overnight and then in vacuum at 40 ° C for 6 hours.

b. UV curing:

Films were irradiated with a Philips Mercury HOK 20/100 (100 W / cm2). The distance between films and the lamp was 30-35 cm so that the temperature of the films was 100 ° C.

c. Determination of insoluble fraction:

The weight of the empty clean glass slides and the weight of the glass slides with the film before and after curing were weighed. After UV or 10 thermal curing, the films were placed in DMSO for 48 hours. After this, the films were dried in vacuum at 100 ° C for 5 hours and the weight was determined again. The insoluble fraction was calculated from the various weightings.

The results of the solubility test were found to be in good agreement with the standard rub test. For the acrylic systems described here, an insoluble fraction greater than 75% usually meant 100 or more chloroform double-rubs. The solubility test was used because this test allowed more accurate comparison within measurement series.

d. Chloroform rub test: 20 Films were formed on 26x76 mm glass slides as described above.

A cotton-wrapped swab had been used. The cotton surface pressure on the coating was constant throughout all experiments (100 N / m2). The tested surface was 0.5x4 cm. The number of double rubs needed to reach the surface was counted. After 100 rubs, the test was stopped and the film was considered fully cured.

1006369

Claims (39)

Use of an oxime-protected isocyanate group of the formula I - R3 - NH - CO - O - N = CR, R2 (I) wherein at least one of the groups R, R2 or R3 has at least one The use according to claim 1, wherein at least the group R or the group R2 carries or comprises the at least one UV absorbing group, or wherein both groups R and R2 comprise or carry at least one UV absorbing group . Use according to any one of the preceding claims, wherein the UV absorbing group is selected from 15. optionally substituted unsaturated hydrocarbon radicals, in particular optionally substituted alkenyl groups with 2-6 carbon atoms and optionally substituted alkynyl groups with 2-6 carbon atoms, as well as cycloalkenyl - and alkylcycloalkenyl groups having a total of 4-10 carbon atoms and preferably 5 or 6 ring carbon atoms; 20. optionally substituted aromatic groups, in particular with a total of 4-8 ring atoms selected from carbon atoms and / or optionally one or more heteroatoms O, S and N; more in particular having 4, 5 or 6 carbon atoms, optionally 1 or 2 hetero atoms, and a total of 5 or 6 ring atoms, such as 1006369 phenyl, furfuryl, pyranyl, pyridinyl and the like; optionally substituted carbonyl groups of 1-10 carbon atoms, carboxyl groups, cyano groups, nitro groups, hydroxyl groups, preferably cyano groups, nitro groups and / or carbonyl groups of 1-6 carbon atoms; 5 wherein the UV absorbing group of the oxime-protected isocyanate group is separated by at most three atoms; preferably by at most two atoms; more preferably by only a further atom; or directly attached to the oxime-protecting isocyanate group; and / or wherein the UV absorbing group is in a position relative to the protected isocyanate group such that resonance can occur between the UV absorbing group and the protected isocyanate group. Use according to any one of the preceding claims, wherein the groups R 1 and R 2 are independently selected from hydrogen; The UV absorbing groups according to claim 3, in particular cyano, nitro, 1-alkynyl groups of 2-6 carbon atoms, 1-carbonyl groups of 1-4 carbon atoms and the above-defined optionally substituted aromatic groups, in particular optionally substituted phenyl groups; optionally substituted alkyl groups of 1-10 carbon atoms, especially 1-6 carbon atoms, more particularly optionally substituted methyl, ethyl, propyl or isopropyl; optionally substituted alkenyl groups of 2-10 carbon atoms; optionally substituted alkynyl groups of 2-10 carbon atoms; optionally substituted cycloalkyl, alkylcycloalkyl, cycloalkenyl and alkylcycloalkenyl groups having a total of 3-10 carbon atoms, and preferably having 5 or 6 ring carbon atoms; halogen; 1006369 optionally substituted alkoxyl groups of 1-10 carbon atoms or alkoxylalkyl groups of 2-10 carbon atoms; hydroxyl; carboxyl; 5. optionally substituted ester groups with 2-10 carbon atoms; amine groups of the formula -N T, T2, wherein T, and T2 may be hydrogen or optionally substituted alkyl of 1-10 carbon atoms, or together form a ring having up to 8 ring atoms; in particular with 3, 4 or 5 carbon atoms and optionally a further nitrogen atom in the ring; sulfhydryl and optionally substituted thioalkyl groups of 1-6 carbon atoms; wherein the groups R, or R2 may also, together with the carbon atom of the oxime-protected isocyanate group to which they are attached, form an optionally substituted ring optionally formed by one or more heteroatoms, carbonyl groups and / or ester groups (to form a lactone ring ) may be interrupted; wherein the above groups may optionally also contain or be interrupted by one or more heteroatoms S, N or O; or optionally further may contain or be interrupted by at least one carbonyl group - (C = 0) - optionally to form an ester, amide or thioester group; and wherein preferably at least one of the groups R, or R2 comprises or carries at least one UV absorbing group. R3 - NH - CO - O - N = CR, R2 (I) wherein Rh are R2 and R3 as defined in claims 1-11, in the side chain. Use according to any one of the preceding claims, wherein the groups R 1 and R 2 are independently selected from hydrogen; 1006369 the UV absorbing groups according to claim 3, in particular cyano, nitro, 1-alkynyl groups of 2-6 carbon atoms, 1-carbonyl groups of 1-4 carbon atoms and the above-defined optionally substituted aromatic groups, especially optionally substituted phenyl groups; 5. optionally substituted alkyl groups of 1-10 carbon atoms, especially 1-4 carbon atoms, more particularly optionally substituted methyl, ethyl, propyl or isopropyl; optionally substituted alkenyl groups of 2-10 carbon atoms; optionally substituted alkynyl groups of 2-10 carbon atoms; 10. optionally substituted cycloalkyl groups having a total of 4-10 carbon atoms and preferably 5 or 6 carbon atoms in the ring; wherein the above groups may optionally also contain or be interrupted by one or more heteroatoms S, N or O; or optionally further may contain or be interrupted by at least one carbonyl group - (C = 0) - optionally to form an ester, amide or thioester group; and wherein preferably at least one of the groups R, or R2 comprises or carries at least one UV absorbing group. 5 comprises or carries a UV absorbing group which makes the group (NH - CO - O - N = C) sensitive to splitting under the influence of UV radiation; in or as side chains of branched polymers or in cross-linking agents, for imparting UV curability to these polymers or to polymeric compositions containing such polymers and / or cross-linking agents. 6. Use according to any one of the preceding claims, wherein the groups R | and R2 are independently selected from the UV absorbing groups according to claim 3, in particular cyano, nitro, 1-alkynyl groups with 2-6 carbon atoms, 1-carbonyl groups with 1-4 carbon atoms and the above-defined optionally substituted aromatic groups, especially optionally substituted phenyl groups; 25. optionally substituted alkyl groups of 1-6 carbon atoms, more particularly optionally substituted methyl, ethyl, propyl or isopropyl; and wherein preferably at least one of the groups R, or R2 comprises or carries at least one UV absorbing group. 1006369 Use according to any one of the preceding claims, wherein the groups R 1 and R 2 are independently selected from methyl, ethyl, phenyl, methylenphenyl (-CH2-C6H5), methylenediphenyl (-CH- (C6H5) 2), nitromethyl, cyanomethyl, ethynyl and α-carbonyl groups of the general formula - (C = O) - R4, wherein R4 is an optionally substituted alkyl group of 1-6 carbon atoms. Use according to any one of the preceding claims, wherein R 1 and R 2 are both phenyl or one of R 1 and R 2 is phenyl and the other is methyl or ethyl. Use according to any one of the preceding claims, wherein the group R 3 is a linking group or bridge, and preferably an optionally substituted alkyl group of 1-10 carbon atoms, an optionally substituted alkenyl group of 2-10 carbon atoms, an optionally substituted alkynyl group of 2 -10 carbon atoms, 15. an optionally substituted alkoxyl group of 1-10 carbon atoms or alkoxyalkyl group of 2-10 carbon atoms; an optionally substituted cycloalkyl, alkylcycloalkyl, cycloalkenyl or alkylcycloalkenyl group having a total of 3-10 carbon atoms, and preferably 5 or 6 ring carbon atoms; 20. an optionally substituted aryl, alkylaryl, arylalkyl or alkylarylalkyl group having a total of 4-10 carbon atoms, and preferably 5 or 6 ring carbon atoms; wherein the above groups may optionally also contain or be interrupted by one or more heteroatoms 25 S, N or O; or optionally 1006369 further may contain or be interrupted by at least one carbonyl group - (C = 0) - optionally to form an ester, amide or thioester group; wherein the group R3 may be optionally substituted with one or more UV-5 absorbing groups according to claim 3 or interrupted by one or more UV absorbing groups according to claim 3; the UV absorbing group usually by no more than three atoms; preferably no more than two atoms; more preferably by only a further atom, separated from the oxime-protected isocyanate group, or bound directly to the oxime-protected isocyanate group, and / or wherein the UV absorbing group is in such a position relative to the protected isocyanate group that resonance can occur between the UV absorbing group and the protected isocyanate group. R3 - NH - CO - O - N = CR, R2 (I) wherein R 1, R 2 and R 3 are as defined in claims 1-11, including a further polymerisable group, and / or wherein R 1 and R 2 as defined in claims 1-8 and R3 is a monomer, a structural unit which can serve as a monomer, or a structural unit comprising a polymerizable group. 10. Use according to any one of the preceding claims, wherein the group R3 is a linking group or bridge being an optionally substituted alkyl group of 1-10 carbon atoms; an optionally substituted alkenyl group of 2-10 carbon atoms; an optionally substituted alkyne group of 2-10 carbon atoms; an optionally substituted alkoxyl group of 1-10 carbon atoms or alkoxyalkyl group of 2-10 carbon atoms; an optionally substituted cycloalkyl, alkylcycloalkyl, cycloalkenyl or alkylcycloalkenyl group having a total of 5-10 carbon atoms, and preferably 5 or 6 ring carbon atoms; an optionally substituted aryl, alkylaryl, arylalkyl, or alkylarylalkyl group having a total of 5-10 carbon atoms, and preferably having 5 or 6 carbon atoms in the ring; wherein these groups may further contain or be interrupted by one or more heteroatoms S, N or O; or optionally further may contain or be interrupted at least one 1006369 carbonyl group - (C = 0) - optionally to form an ester, amide or thioester group. Use according to any one of the preceding claims, wherein the group R3 is a branched or unbranched, optionally substituted alkyl group with 1-10 carbon atoms, in particular with 1-6 carbon atoms, more in particular with 2-4 carbon atoms, which when it contains more than 2 carbon atoms may be interrupted by an optionally substituted phenyl group, a carbonyl group - (C = 0) - or an ester bond - O - (C = 0) -; or an optionally substituted methylphenyl (-CH2-C6H4-) or phenylmethyl group (-C6H4-CH2-) group. Use according to any one of claims 1-8, wherein the group R3 has a polymeric side chain; a monomer, a structural unit that can serve as a monomer, or a structural unit that comprises a polymerizable group; 15. a cross-linking agent, a structural unit which, due to the further presence of the oxime-protecting isocyanate group, can serve as a cross-linking agent, or a structural unit containing a further cross-linking group; is. Use of a compound containing at least one oxime-protected isocyanate group of the formula I - R3 - NH - CO - O - N = CR, R2 (I), wherein R1, R2 and R3 as defined in claims 1 -12 are, 1006369 in imparting UV curability to polymeric compositions and / or in the preparation of UV curable polymeric compositions. Use according to claim 13, wherein the compound is a polymer having at least one oxime-protected isocyanate group of the formula I Use according to any one of claims 13-14, wherein the polymer is an acrylate or methacrylate based polymer. Use according to any one of claims 13-15, wherein the polymer 10 further contains side chains with functional epoxide groups. Use according to claim 13, wherein the compound is a cross-linking agent comprising at least one oxime-protected isocyanate group of the formula - R 3 - NH - CO - O - N = CR, R2 (I) 15 wherein R 1, R 2 and R 3 as defined in claims 1-11, and contains at least one further cross-linking group. The use of claim 17, wherein the further cross-linking group is a further oxime-protected isocyanate group of 1006369 formula -NH - CO - O - N = CR, R2, wherein R 1 and R 2 are as defined in claims 1-8 . Use of a polymerizable monomer containing at least one oxime-protected isocyanate group of the formula I - R3 - NH - CO - O - N = CR, R2 (I) wherein R1, R2 and R3 as defined in claims 1- 11, as well as a further polymerizable group, in the preparation of UV crosslinkable polymers and / or polymers to impart UV curability to polymeric compositions. The use of claim 19, wherein the monomer is such that the polymerizable group is included in the polymer base chain, while at least the portion of the monomer containing the oxime-protected isocyanate group forms a side chain of the polymer. A UV-curable cross-linkable polymer, comprising a polymeric base chain and at least one side chain, the side chain having at least one oxime-protected isocyanate group of the formula - R3 - NH - CO - O - N = CR, R2 (I) wherein R1, R2 and R3 are as defined in claims 1-11, 1006369 * and / or R1, R2 and R3 are as defined in claims 1-8 and R3 is a side chain of the polymer. A polymer according to claim 21, which is an acrylate polymer. 23. A polymer according to claim 21 or 22, further comprising side chain with functional epoxide groups. 24. Monomer, for the preparation of UV crosslinkable polymers and / or of polymers for imparting UV curability to polymeric compositions, containing at least one oxime-protected isocyanate group of the formula I The monomer of claim 24, wherein the monomer is such that the polymerizable group is included in the polymer base chain, while at least forming the portion of the monomer containing the oxime-protected isocyanate group in the side chain of the polymer. Crosslinking agent, comprising at least one oxime-protected isocyanate group of the formula 1006369> - R3 - NH - CO - O - N = CR, R2 (I) wherein R1, R2 and R3 are as defined in claims 1-11, and at least one further cross-linking group, or wherein R 1 and R 2 are as defined in claims 1-8 and R 3 is a cross-linking agent, a structural unit which can serve as a cross-linking agent due to the further presence of the oxime-protecting isocyanate group, or a structural unit a further cross-linking group is. Use according to any one of claims 1-12 or 13-20, of a polymer according to any one of claims 21-23 or of a cross-linking agent according to claim 10 26, for imparting UV curability to polymeric coating compositions and / or for the preparation of UV curable polymeric coating compositions. Use according to claim 27, for imparting UV curability to polymeric powder coatings and / or for preparing UV curable polymeric powder coatings. A UV-curable polymeric composition obtained or obtainable by the use according to any one of claims 1-12, 13-20 or 27-28, or comprising a polymer according to claims 21-23 or a cross-linking agent according to claim 26. 30. A UV-curable polymeric composition according to claim 29, being a coating composition. The UV-curable polymeric composition according to claim 29 or 30, which is a powder coating. 100 6369> A method for curing / cross-linking a polymeric composition according to any one of claims 29-31, or for curing / cross-linking a polymer according to any one of claims 21-23, comprising exposing the polymeric composition or polymer to suitable UV radiation. The method of claim 31, wherein the curing / crosslinking is performed at a temperature of less than 130 ° C, more particularly less than 110 ° C. A cured polymeric article obtained or obtainable according to the method of claims 32-33. The article of claim 34, which is a coating and / or a coated article / substrate. 36. Use of oximes of the formula II HO - N = CR, R2 (II) in which at least one of the groups R, and / or R2 comprises or carries a UV absorbing group as defined above, for protecting isocyanate groups in compounds, especially in polymers, to provide these compounds / polymers with UV curability. 37. Use of a UV activating agent in a composition containing at least one further compound with an oxime-protected isocyanate group of the formula I, 100 6369 - R3 - ΝΗ - CO - Ο - Ν = CR, R2 (I) wherein R 1, R 2 or R 3 may be as defined in claims 1-11, wherein the UV activating agent makes the group (NH-CO-O-N = C) sensitive to cleavage under the influence of UV-5 radiation. The use of claim 37, wherein the further compound having the oxime-protected isocyanate group of formula I is a polymer with the oxime-protected isocyanate group in the side chain. A polymeric composition, at least comprising a polymer with oxime-10 protected isocyanate groups of the formula I, - R 3 - NH - CO - O - N = CR, R2 (I) wherein R 1, R 2 or R 3 as defined in claims 1 -11, in the side chain, as well as a UV activating agent that makes the group (NH - CO - O - N = C) sensitive to cleavage under the influence of υνί 5 radiation. 1006369