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Title:
MODIFIED BLOCK COPOLYMER
Document Type and Number:
WIPO Patent Application WO/2008/025727
Kind Code:
A1
Abstract:
The invention relates to a modified block copolymer obtainable by reaction of at least a part of the cyclic anhydride groups of (i) a polycyclic methacrylic anhydride block copolymer comprising at least one block A comprising a plurality of cyclic polymerized units of methacrylic anhydride and at least one block B comprising polymerized units of vinyl monomers, wherein block B is essentially free of cyclic polymerized units of methacrylic anhydride, with (ii) a cyclic anhydride-reactive compound having at least one cyclic anhydride-reactive group.

Inventors:
VENDERBOSCH, Rudolf Anthonius Maria (Klavecimbelstraat 6, JL Duiven, NL-6922, NL)
BRINKHUIS, Richard Hendrikus Gerrit (Groot Wezenland 33, JX Zwolle, NL-8011, NL)
Application Number:
EP2007/058793
Publication Date:
March 06, 2008
Filing Date:
August 24, 2007
Export Citation:
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Assignee:
AKZO NOBEL COATINGS INTERNATIONAL B.V. (Velperweg 76, BM Arnhem, NL-6824, NL)
VENDERBOSCH, Rudolf Anthonius Maria (Klavecimbelstraat 6, JL Duiven, NL-6922, NL)
BRINKHUIS, Richard Hendrikus Gerrit (Groot Wezenland 33, JX Zwolle, NL-8011, NL)
International Classes:
C08F8/00; C08F293/00; C09D153/00; C09J153/00
Attorney, Agent or Firm:
SCHALKWIJK, Pieter Cornelis (Akzo Nobel N.V, Intellectual Property Department P.O. Box 9300, SB Arnhem, NL-6800, NL)
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Claims:

CLAIMS

1. A modified block copolymer obtainable by reaction of at least a part of the cyclic anhydride groups of (i) a polycyclic methacrylic anhydride block copolymer comprising at least one block A comprising a plurality of cyclic polymerized units of methacrylic anhydride and at least one block B comprising polymerized units of vinyl monomers, wherein block B is essentially free of cyclic polymerized units of methacrylic anhydride, with

(ii) a cyclic anhydride-reactive compound having at least one cyclic anhydride-reactive group.

2. A modified block copolymer according to claim 1 , wherein the polycyclic methacrylic anhydride block copolymer comprises at least 5% by weight of cyclic polymerized units of methacrylic anhydride, calculated on the total weight of the polycyclic methacrylic anhydride block copolymer.

3. A modified block copolymer according to claim 1 or 2, wherein block A of the polycyclic methacrylic anhydride block copolymer comprises at least

30% by weight of cyclic polymerized units of methacrylic anhydride.

4. A modified block copolymer according to any one of the preceding claims, wherein the at least one cyclic anhydride-reactive group in the cyclic anhydride-reactive compound is selected from hydroxyl groups, amino groups, thiol groups, and epoxide groups.

5. A modified block copolymer according to any one of the preceding claims, wherein the cyclic anhydride-reactive compound comprises at least one

further functional group, which may be the same as or different from the at least one cyclic an hydride- reactive group.

6. A modified block copolymer according to claim 5, wherein the at least one further functional group is different from the at least one cyclic anhydride- reactive group.

7. A modified block copolymer according to claim 6, wherein the cyclic anhydride-reactive compound comprises amino groups and hydroxyl groups.

8. A modified block copolymer according to claim 7, wherein the cyclic anhydride-reactive group comprises primary and/or secondary amino groups.

9. A modified block copolymer according to any one of the preceding claims, wherein the number average molecular weight of block A is at least 500.

10. A modified block copolymer according to any one of the preceding claims, wherein the number average molecular weight of block A does not exceed

20,000.

1 1. A modified block copolymer according to any one of the preceding claims, wherein the number average molecular weight of block B is in the range of 500 to 20,000.

12. A modified block copolymer according to any one of the preceding claims, wherein the modified block copolymer comprises imide groups obtained by the reaction of cyclic anhydride groups of block A with a cyclic anhydride- reactive compound comprising at least one primary amino group.

13. Use of a modified block copolymer according to any one of the preceding claims as a binder, dispersant, surfactant, compatibilizer, or adhesion promoter in a coating composition.

14. Use according to claim 13, wherein the coating composition comprises a curing agent.

15. Use according to claim 14, wherein the modified block copolymer comprises hydroxyl groups and the curing agent comprises hydroxyl- reactive functional groups.

Description:

Modified block copolymer

The invention relates to a modified polycyclic methacrylic anhydride copolymer. The invention further relates to the use of the modified copolymer as a binder, dispersant or surfactant in a coating composition.

A modified polycyclic methacrylic anhydride copolymer of the above-mentioned type is known from EP 0537028 A. This document describes dispersants which are based on the reaction product of polyols with homo- or copolymers containing anhydride groups. In one embodiment the dispersant uses an ethylenically unsaturated carboxylic anhydride monomer. Methacrylic anhydride is mentioned as a suitable ethylenically unsaturated carboxylic anhydride monomer.

EP 0825202 A describes acid- and amine-functional polymers, and a method for their preparation. The method comprises the steps of copolymerizing an anhydride monomer with an ethylenically unsaturated monomer to produce an anhydride polymer, and allowing the copolymer to react with a diamine. Methacrylic anhydride is mentioned as a suitable anhydride monomer. The formation of cyclic polymerized units of methacrylic anhydride is not mentioned. Where an aqueous medium is utilized, dispersions of the resins may be in the form of single or multi-staged particles. Multi-staged particles comprise at least two mutually incompatible copolymers having for example a core/shell morphology.

A drawback of the known modified anhydride copolymers is that functional groups within the individual polymer molecules are distributed at random. Under the polymerization conditions of EP 0825202 A the formation of cyclic polymerized units of methacrylic anhydride is not favoured. Instead, methacrylic anhydride at least partially behaves like a difunctional ethylenically unsaturated monomer, giving rise to branching and crosslinking. Therefore, control of

molecular weight is difficult, in particular when high proportions of methacrylic anhydride are used. However, for many applications of modified anhydride copolymers it is desirable to have a controlled molecular weight, even at high proportion of methacrylic anhydride. It is also desirable that modifying and/or functional groups are not distributed at random within the individual polymer molecules, but in a controlled and well-defined manner. For example, when a functional copolymer is used as crosslinkable binder, the properties of the crosslinked material are determined by the crosslink density. In addition to the average crosslink density, it is also desirable to control the size distribution of the network loops of the crosslinked polymer.

Such control is only possible when the crosslinkable functional groups are distributed along the polymer molecules in a controlled and predictable manner, as opposed to being distributed at random. Furthermore, in the field of dispersants and compatibilizers it is often desirable to have a well-defined distribution of polar and apolar segments in individual polymer molecules.

The present invention seeks to provide modified cyclic anhydride copolymers which do not have the above-mentioned drawbacks. More in particular, the modifying and/or functional groups in the modified copolymers should be distributed in a controlled and well-defined manner.

The invention now provides a modified block copolymer obtainable by reaction of at least a part of the cyclic anhydride groups of (i) a polycyclic methacrylic anhydride block copolymer comprising at least one block A comprising a plurality of cyclic polymerized units of methacrylic anhydride and at least one block B comprising polymerized units of vinyl monomers, wherein block B is essentially free of cyclic polymerized units of methacrylic anhydride, with

(ii) a cyclic an hydride- reactive compound having at least one cyclic anhydride-reactive group.

In the modified block copolymer according to the invention the modifying and/or functional groups in the modified copolymer are distributed in a controlled and well-defined manner.

The polycyclic methacrylic anhydride block copolymer comprises at least one block A comprising a plurality of cyclic polymerized units of methacrylic anhydride. Block A comprises at least 2, preferably at least 3 cyclic polymerized units of methacrylic anhydride. In one embodiment, block A comprises 4 to 30 cyclic polymerized units of methacrylic anhydride. Block A suitably comprises at least 30% by weight, preferably at least 50% by weight, and more preferably at least 80% by weight of cyclic polymerized units of methacrylic anhydride, calculated on the total weight of block A. In addition to cyclic polymerized units of methacrylic anhydride, block A may also comprise polymerized units of other ethylenically unsaturated polymehzable monomers, as described below for block B, provided that the other ethylenically unsaturated polymehzable monomers for block A are essentially free of cyclic anhydride-reactive groups. It is also possible that block A will consist essentially of cyclic polymerized units of methacrylic anhydride, i.e. polymerized units of other ethylenically unsaturated polymerizable monomers may be essentially absent from block A. The number average molecular weight of block A suitably is at least 500, preferably at least 1 ,000, and more preferably at least 1 ,500. The number average molecular weight of block A suitably does not exceed 30,000, preferably it does not exceed 20,000, and more preferably it does not exceed 15,000.

Block B of the polycyclic methacrylic anhydride copolymer is essentially free of cyclic polymerized units of methacrylic anhydride.

Block B may comprise polymerized units of any ethylenically unsaturated monomers, preferably ones rich in methacrylates, and can be made, e.g., by catalytic chain transfer polymerization, high temperature polymerization, or by reversible addition fragmentation reactions. Examples of suitable ethylenically unsaturated monomers for use in block B are given below, the term (meth)acrylate embracing both acrylates and methacrylates: alkyl (meth)acrylates of straight-chain, branched or cycloaliphatic alcohols having 1 to 22 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and t-butyl (meth)acrylate; aryl (meth)acrylates, such as benzyl (meth)acrylate or phenyl acrylate, the aryl radicals in each case being unsubstituted or substituted up to four times, such as 4-nitrophenyl methacrylate; acrylic acid, methacrylic acid, maleic acid, and salts and esterified derivatives thereof; hydroxyalkyl (meth)acrylates of straight-chain, branched or cycloaliphatic diols having 2 to 36 carbon atoms, such as 3-hydroxypropyl methacrylate, 3,4-dihydroxybutyl monomethacrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)- acrylate, 2-hydroxypropyl methacrylate, and 2,5-dimethyl-1 ,6-hexanediol mono- methacrylate; mono(meth)acrylates of ethers, polyethylene glycols, polypropylene glycols or mixed polyethylene/propylene glycols having 5 to 80 carbon atoms, such as tetrahydrofurfuryl (meth)acrylate, methoxyethoxyethyl (meth)acrylate, 1 -butoxypropyl (meth)acrylate, cyclohexyloxymethyl (meth)- acrylate, methoxymethoxyethyl (meth)acrylate, benzyloxymethyl (meth)acrylate, furfuryl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)- acrylate, allyloxymethyl (meth)acrylate, 1 -ethoxybutyl (meth)acrylate, 1 - ethoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, poly(ethylene glycol) methyl ether (meth)acrylate, and polypropylene glycol) methyl ether (meth)- acrylate; caprolactone- and/or valerolactone-modified hydroxyalkyl (meth)- acrylates having an average molecular weight of from 220 to 1 ,200, the hydroxy

(meth)acrylates being derived preferably from straight-chain, branched or cycloaliphatic diols having 2 to 8 carbon atoms. However, in view of the possible reaction of hydroxyl groups with anhydride groups and the associated risk of gelation, hydroxy-functional (meth)acrylates should only be used in small amounts, if at all.

Other suitable monomers are aminoalkyl (meth)acrylates, such as N, N- dimethylaminoethyl (meth)acrylate, 2-thmethyl ammonioethyl methyl (meth)acrylate chloride, and N,N-dimethyl aminopropyl (meth)acrylate; (meth)acrylates of halogenated alcohols, such as perfluoroalkyl (meth)acrylates having 6 to 20 carbon atoms; oxiranyl (meth)acrylates such as 2,3-epoxybutyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and glycidyl (meth)acrylate; styrene and substituted styrenes, such as 4-methylstyrene, 4-vinylbenzoic acid, and sodium 4-vinylbenzene sulphonate; methacrylonithle and acrylonitrile; ethylenically unsaturated heterocycles, such as 4-vinylpyhdine and 1 -[2- (methacryloyloxy)ethyl]-2-imidazolidinone; monomers containing phosphoric or phosphonic acid, such as thpropylene glycol methacrylate phosphate, hydroxyethyl methacrylate phosphate, vinyl phosphonic acid, and styrene phosphonic acid; ethylenically unsaturated sulphonic acids and sulphates and also their salts, such as potassium [3-(meth- acryloyloxy)propyl] sulphonate and ammonium [2-(methacryloyloxy)ethyl] sulphate; vinyl esters of carboxylic acids having 1 to 20 carbon atoms, such as vinyl acetate; maleimide, N-phenyl maleimide, and N-substituted maleimides with straight-chain, branched or cycloaliphatic alkyl groups having 1 to 22 carbon atoms, such as N-ethyl maleimide and N-octyl maleimide; (meth)- acrylamide; N-alkyl- and N,N-dialkyl-substituted acrylamides with straight-chain, branched or cycloaliphatic alkyl groups having 1 to 22 carbon atoms, such as N- (t-butyl)acrylamide and N,N-dimethylacrylamide; silyl-containing (meth)- acrylates, such as (meth)acrylic acid thmethylsilyl ester and (meth)acrylic acid 3-(trimethylsilyl)propyl ester.

The number average molecular weight (Mn) of block B generally is at least 800, preferably at least 1 ,200, and more preferably at least 1 ,500. The number average molecular weight (Mn) of block B preferably is at most 20,000, more preferably at most 10,000, and even more preferably at most 5,000.

As mentioned above, the polycyclic methacrylic anhydride block copolymer comprises cyclic polymerized units of methacrylic anhydride. The amount of these cyclic polymerized units of methacrylic anhydride suitably is at least 5% by weight, or at least 10% by weight, or at least 25% by weight, calculated on the total weight of the polycyclic methacrylic anhydride block copolymer.

As mentioned above, the polycyclic methacrylic anhydride block copolymer comprises at least one block A and at least one block B. In one embodiment, the copolymer consists essentially of one block A and one block B. Alternatively, the polycyclic methacrylic anhydride block copolymer comprises a plurality of blocks A and blocks B, in such a way that blocks A and blocks B alternate. The terminating blocks may be A blocks or B blocks. It is also possible that the polycyclic methacrylic anhydride block copolymer will comprise segments or blocks of polymerized monomers different from block A and block B, i.e. a block C. Depending on the intended use of the modified polycyclic methacrylic anhydride block copolymer, it may be advantageous that A blocks and B blocks exhibit a large difference in polarity. The B block may be an apolar macromonomer, whereas the A block has a higher polarity on account of the presence of the cyclic anhydride groups. Upon modification, the polarity of the A block may be further increased by reaction of the cyclic anhydride groups with polar modifying agents, such as water, hydroxy acids, polyether amines or polyether alcohols.

The A block, containing the anhydride functionality, is suitably prepared by reacting the B block with methacrylic anhydride in the presence of an initiator. The amount of mole initiator preferably does not exceed the moles of block B.

Optionally, a solvent may be used. It has been found that the formation of cyclic polymerized units of methacrylic anhydride is favoured by a high viscosity of the reaction medium. At lower viscosities methacrylic anhydride behaves more like a normal difunctional ethylenically unsaturated monomer, leading to the formation of branches and/or crosslinks. Therefore, it is preferred to carry out the preparation of block A at high viscosity. The reaction is performed at elevated temperature, such as 8O 0 C, at least at 1 1 O 0 C, or at least at 13O 0 C. Reaction temperatures generally will not exceed 19O 0 C, or 17O 0 C. The methacrylic anhydride is preferably dosed under starved conditions in preferably at least one hour, more preferably at least two hours, and most preferably at least three hours, with the macro-monomer block B being pre-added to the reactor.

The methacrylic anhydride is dosed preferably as a mixture containing at least 50% by weight of methacrylic anhydride and optionally other ethylenically unsaturated polymehzable monomers. The total amount of solvent during the preparation of the A block preferably is less than 50% by weight, more preferably less than 25% by weight, or even more preferably less than 10% by weight. The solvent used in the process should not significantly interfere with the radical polymerization or with the functional groups present in the monomers and/or the polymer formed. Water or solvent mixtures containing water can cause hydrolysis of anhydride groups. Therefore, aqueous solvents are not preferred. Examples of suitable solvents include esters, such as butyl acetate, N, N- dimethylformamide, xylene, toluene, and ketones.

The B block is suitably provided in the form of a polymer or oligomer having an end group capable of initiating or maintaining a radical polymerization. In one embodiment, block B is provided in the form of a macro-monomer, i.e. a polymer having an ethylenically unsaturated end group. The macro-monomer has the following general structure:

wherein X is a phenyl, ester or acid group.

In a different embodiment, block B is provided in the form of a polymer having an end group capable of forming radicals. Block B may be prepared by a living radical polymerization technique. Such techniques are generally known to the skilled person. The polymer may consist of any ethylenically unsaturated monomers, preferably ones rich in methacrylates, and can be made by various polymerization techniques, such as catalytic chain transfer polymerization, high temperature polymerization, and reversible addition-fragmentation-reactions. For the person skilled in the art it will be obvious that it may not contain a too high proportion of monomers with functionalities which can react with anhydrides, because otherwise gelation will occur and functionality will be lost. Anhydride-reactive monomers can be used in the A block or in the B block, however, to deliberately introduce branching in the polycyclic methacrylic anhydride block copolymer.

The polycyclic methacrylic anhydride block copolymer is modified by reaction of at least a part of the cyclic anhydride groups with a cyclic anhydride-reactive compound having at least one cyclic anhydride-reactive group. Examples of suitable cyclic anhydride-reactive groups are hydroxyl groups, primary and secondary amino groups, thiol groups, and epoxide groups. The modification reaction can be performed at any moment, depending on the intended application, and at any temperature, depending on the nature of the at least one cyclic anhydride-reactive group. In one embodiment, the modification can be carried out in situ, e.g. for pigment dispersants in the presence of a pigment.

The modification reaction can be carried out in one or more steps, using one or more modifying agents. In one embodiment, a first step of the modification reaction can be carried out wherein a part of the cyclic anhydride groups is reacted with a first cyclic anhydride-reactive compound, followed by a second step wherein at least a part of the remaining cyclic anhydride groups is reacted with a second cyclic anhydride-reactive compound which is different from the first cyclic anhydride-reactive compound. It is also possible to carry out the modification with a mixture of two or more different cyclic anhydride-reactive compounds. Alternatively, a first step can be carried out wherein at least a part of the cyclic anhydride groups is reacted with a cyclic anhydride-reactive compound, forming a carboxylic acid derivative, such as an ester or amide, and a carboxylic acid group, followed by a second step wherein the carboxylic acid group thus formed is reacted with a carboxylic acid-reactive compound. Examples of suitable carboxylic acid-reactive compounds are basic compounds capable of salt formation with the carboxylic acid groups and epoxy group- containing compounds.

In one embodiment, the cyclic anhydride-reactive compound comprises any compound, or mixture of compounds, with a reactivity towards anhydride, e.g. compounds with the general formula Z-Q, wherein Q is hydroxy, primary amino, NHR 1 or SH wherein R 1 is Cl-, -alkyl and especially C-4-alkyl, and Z is an aliphatic group with from 2 to 10 carbon atoms containing at least one tertiary amino group or a heterocyclic group containing at least one basic ring nitrogen atom which carries no hydrogen atom, and where the heterocyclic group may be attached to Q by an alkylene group containing up to 10 carbon atoms. Preferably, Z is a mononuclear or dinuclear heterocyclic group having a ring nitrogen atom which is attached to Q, preferably by an alkylene group. Preferred heterocyclic groups are optionally substituted triazole, pyrimidine, imidazole, pyridine, morpholine, pyrrolidine, piperazine, benzimidazole, benzothiazole and/or thazine. Substituents may be C 6 - and especially C 4 -alkyl or alkoxy or amino.

As noted hereinbefore, Q may be attached to Z via an alkylene group containing up to 10 carbon atoms, preferably C 2 -8-alkylene and especially C 2 - 4 -alkylene. Q may also be attached to Z via a polyether group containing the same number of carbon atoms as the alkylene group. Examples of Z-Q are N,N-diethyl-1 ,4-butane diamine, 1 -(2-aminoethyl)- piperazine, 2-(1 -pyrrolidyl)-ethylamine, 4-amino-2-methoxypyrimidine, 2- dimethylaminoethanol, 1 -(2-hydroxyethyl)-piperazine, 4-(2-hydroxyethyl)- morpholine, 2-mercaptopyhdine, 2-mercaptobenzimidazole, N,N-dimethyl-1 ,3- propane diamine, 4-(2-aminoethyl)-pyridine, 2-amino-6-methoxy-benzo-thiazole, 4-(aminomethyl)-pyridine, N,N-diallylmelamine, 3-amino-1 ,2,4-triazole, 1 -(3- aminopropyl)-imidazole, 4-(2-hydroxyethyl)-pyhdine, 1 -(2-hydroxyethyl)- imidazole, 3-mercapto-1 ,2,4-thazole. It is a characteristic of these compounds that they contain at least one Zerewitinoff-active hydrogen atom per molecule, which hydrogen atom preferably reacts with the anhydride group. Optionally, it is possible to modify the resins to comprise imide groups. The imide groups are suitably obtained by reaction of the cyclic anhydride of block A with a cyclic anhydride-reactive compound comprising at least one primary amino group. In a first step of the reaction an amic acid is formed. By heat treatment ring closure of the amic acid to imide will take place. Also functionalization to quaternary ammonium salts is possible, e.g., reaction of the anhydride with N,N-diethyl-1 ,4-butane diamine followed by a reaction with benzyl chloride.

It also possible to modify the anhydride polymer with a mixture of the mentioned amines and a polymer which is reactive towards anhydrides for compatibility with a desired matrix, e.g. polyethylene oxides, Jeffamines for an aqueous environment or poly-caprolactone for organic systems or a combination of both. Modification with amino (poly)ethers or alkoxy (poly)ethers will result in surfactants which can give electrostehc stabilization. Such modified compounds can for example be used in emulsion polymerizations or in emulsification processes.

Also here the acid groups may be used for further modification, such as esterification and/or salt-formation, if desired.

In one embodiment, the cyclic anhydride-reactive compound comprises at least one further functional group, which may be the same as or, preferably, different from the at least one cyclic anhydride-reactive group. It is preferred that the two or more functional groups have different reactivities towards cyclic anhydride groups.

Examples of such compounds are diols and polyols, in particular diols wherein the two hydroxyl groups have different reactivities. For example, one hydroxyl group may be a primary hydroxyl group, and the second hydroxyl group may be a secondary or tertiary hydroxyl group. Also, the absence or presence of branching in the proximity of the hydroxyl groups can influence the reactivity due to stehcal effects. Diamines, dicarboxylic acids, amino alcohols, amino carboxylic acids, and hydroxy carboxylic acids are further examples of compounds having a cyclic anhydride-reactive group and one further functional group. Amino alcohols comprising primary and/or secondary amino groups and hydroxyl groups may be mentioned in particular.

The modified block copolymer according to the invention can be used for a large variety of different purposes. This suitability for particular purposes depends, among other factors, on the type of modification reaction carried out, as described above. The modified block copolymer can for example be used as a surfactant or as a precursor for surfactants, as an emulsifier, compatibilizer, adhesion promoter, and dispersing agent, such as a dispersing agent for pigments. The modified block copolymer can also be used as a film-forming binder, for example in coating and adhesive compositions. Such compositions may be organic solvent based compositions, solvent-free compositions, high- solids compositions, or water based compositions.

As mentioned above, the modified block copolymer can have functional groups susceptible to crosslinking of the modified block copolymer. Examples of

suitable functional groups are hydroxyl groups, amine groups, carboxylic acid groups. When the modified block copolymer is used in a coating composition, it is preferred that the coating composition additionally comprises a curing agent. In one embodiment, the curing agent is capable of crosslinking the modified block copolymer by reaction with the functional groups thereof. For instance, when the modified block copolymer comprises hydroxyl groups, the curing agent suitably comprises hydroxyl- reactive functional groups, such as isocyanate groups. Also etherified melamine-formaldehyde condensates or similar amino resins are suitable as curing agents for hydroxyl-functional modified block copolymers.

Examples:

The molecular weights were determined by size exclusion chromatography using polystyrene as standard.

The following raw materials were used:

Perkadox AMBN: 2,2' azobis(2-methylbutyronitrile), ex Akzo Nobel NOR 3: a nitroxyl polymerization mediator as indicated in Figure 1 of F. O. H. Pirrung and C. Auschra in Polymer Preprints 2005, 46, pp. 316 - 317.

Example 1 Preparation of methyl methacrylate based macro-monomer

Into a 3-litre four-necked, round-bottomed flask equipped with a mechanical stirrer, a cooler, a dropping funnel, a N 2 -inlet, and a temperature sensor 200 grams (2.00 moles) of methyl methacrylate and 236.36 grams of α-methyl styrene dimer were weighed. The mixture was heated to reflux, 1 14 Q C, when the addition of a mixture of 1 ,800.00 grams (17.98 moles) of methyl methacrylate,

236.36 grams (1.00 mole) of α-methyl styrene dimer, 30.00 grams of azobisisobutyronitile, and 191.82 grams of o-xylene was dosed at a rate of 2.8 grams/minute.

After one hour, during which the temperature was gradually raised to 142 Q C, the dosing speed was raised to 5.6 grams per minute. All monomers were added in 6 hours and 40 minutes and this was followed by a boost in which 6.00 grams of azobisisobutyronitrile in 56.32 grams of o-xylene were added over a period of 40 minutes. After 30 minutes the reaction medium was diluted by adding 149.19 grams of o-xylene to a non-volatile content of 85% by weight. The conversion of methyl methacrylate was above 96.5 mole%. The number average molecular weight (Mn) was 1 ,820, the weight average molecular weight (Mw) was 3,030.

Example 2 Preparation of butyl methacrylate based macro-monomer

Into a 5-litre four-necked, round-bottomed flask equipped with a mechanical stirrer, a cooler, a dropping funnel, a N 2 -inlet, and a temperature sensor 300 grams of butyl methacrylate and 236.36 grams of α-methyl styrene dimer were weighed. The mixture was heated to reflux, 143 Q C, when the addition of a mixture of 2,700.00 grams of butyl methacrylate and 45.00 grams of azobisisobutyronitrile was dosed over a period of 5.5 hours. After 30 minutes, 4.50 grams of azobisisobutyronitrile in 45.00 grams of o- xylene were added over a period of 30 minutes. The non-volatile content was 98.7% by weight, the conversion of butyl methacrylate was 93.1 mole%, Mn 2,645, Mw 4,180.

Example 3 Preparation of a block copolymer containing 50% by weight of polymethyl methacrylate and 50% by weight of polymerized methacrylic anhydride

Into a four-necked round-bottomed flask equipped with a mechanical stirrer, a cooler, a dropping funnel, and a temperature sensor 612.14 grams of a solution of Example 1 , containing 520.32 grams of resin, were weighed and brought to 142 Q C. Over a period of 5.5 hours a mixture of 520.32 grams (3.375 moles) of methacrylic anhydride, 346.88 grams of o-xylene, and 7.80 grams of Perkadox AMBN was dosed. 1.95 grams of AMBN in 78.05 grams of o-xylene were next run in over a period of 20 minutes. 30 Minutes later the reaction was stopped and the resin discarded from the reactor. Conversion double bonds methacrylic anhydride: >94.2 mole% Molecular weight: Mn 2,835, Mw 9,130

This block copolymer can be modified as described for the block copolymer of Example 4.

Example 4 Preparation of a AB block copolymer containing 80% by weight of polybutyl methacrylate and 20% by weight of polymerized methacrylic anhydride

Into a four-necked round-bottomed flask equipped with a mechanical stirrer, a cooler, a dropping funnel, and a temperature sensor 162.40 grams of a solution of Example 2, containing 160.29 grams of resin, were weighed and brought to

142 Q C.

Over a period of 5.5 hours a mixture of 40.07 grams of methacrylic anhydride,

13.36 grams of o-xylene, and 0.60 grams of Perkadox AMBN was dosed. 0.15 grams of Perkadox AMBN in 10.00 grams of o-xylene were next run in over a period of 30 minutes. 30 Minutes later the reaction was stopped and the resin discarded from the reactor.

Conversion double bonds methacrylic anhydride: 91 mole %

Molecular weight: Mn 3,025, Mw 6,540

Example 5 Silane modified block copolymer

Into 77.02 grams of a 69.4% solution of the copolymer of Example 4 in o- xylene, 38.86 grams of o-xylene were weighed together with 1 1.78 grams of aminopropyl trimethoxysilane, at room temperature. Amine value: 5.8 mg KOH/gram

Example 6

To 1 10.25 grams of a 70.7% solution of the copolymer of Example 4 in o- xylene, 1 1.86 grams (94.8 mmoles) of 3-aminopropyl imidazole were added.

After heating the reaction mixture for 1 hour at 100 Q C the reaction was stopped.

Acid value: 29.7 mg KOH/g

Amine value: 39.7 mg KOH/g Mn 780; Mw 3,860

Example 7

To 116.50 grams of a 70% solution of the copolymer of Example 4 in o-xylene were added 12.53 grams of 3-aminopropyl imidazole. After heating the reaction mixture for 1 hour at 100 Q C the reaction was stopped. The reaction mixture was heated to 120 Q C and 9.93 grams of ethyl oxazoline were added. After 8 hours the reaction was stopped.

Acid value: 4.0 mg KOH/g Amine value: 27.8 mg KOH/g

Mn 760; Mw 4,430

Example 8

To a mixture of 5.38 grams of Epomine SP200 (polyethylene imine) in 45 grams of o-xylene/5.0 grams of methanol a mixture of 89.41 grams of a 20.0% solution of the copolymer of Example 4 in o-xylene was added over a period of 1.5 hours. The reaction mixture was heated to 100 Q C and a part of the solvents was distilled off. After 2 hours the reaction was stopped. Non-volatile content: 22.4% by weight Acid value: 15.0 mg KOH/g Amine value: 12.4 mg KOH/g Mn 3,990; Mw 13,400