GB2037301A - Process for the manufacture of copolymers which carry hydroxyl groups and are soluble in organic solvents, using an esterification catalyst - Google Patents

Abstract

The invention relates to a process of the manufacture of copolymers from vinyl compounds, an alpha, beta- unsaturated monocarboxylic acid and a monoepoxy compound, which polymers carry hydroxyl groups and are soluble in organic solvents is characterised in that first the alpha, beta-unsaturated monocarboxylic acid is esterified with the monoepoxy compound in the presence of at least one vinyl compound and at least one esterification catalyst comprising an alkali metal compound and the copolymerisation is then carried out in the presence of an inert solvent, a further vinyl compound or further vinyl compounds optionally being added before or during the copolymerisation, with the proviso that at least two vinyl compounds must be present, in addition to the momeric esterification product, in the reaction batch when carrying out the copolymerisation stage.

Description

SPECIFICATION Process for the manufacture of copolymers which carry hydroxyl groups and are soluble in organic solvents, using an esterification catalyst German Patent Specification 1,037,754 describes a process for the manufacture of esterified polyhydroxy copolymers. This known process is characterised in that (a) a short-chain a,p-unsaturated monocarboxylic acid, (b) a vinyl monomer with only one active, terminal CH2=C=group capable of addition polymerisation and (c) a monoepoxide, which is an alkylene oxide, which is optionally substituted by alkyl, or an ether or ester with only one three-membered epoxide substituent, the monoepoxide having no other reactive group, are reacted at the same time and in the presence of an epoxy-carboxy catalyst and a catalyst for vinyl polymerisation.With this process, the reaction must always be carried out in the presence of an epoxy-carboxy catalyst and of a catalyst for vinyl polymerisation, at the same time. As repetition of the examples given in this specification has shown, these known copolymers give yellow to brownish coloured solutions. The lacquer films produced therefrom display an undesirable yellow to brown coloration after evaporation of the solvent, so that these products can find only very restricted application.

French Patent Specification 1,390,572 also describes a process for the manufacture of esterified polyhydroxy copolymers, the addition reaction between the epoxy group and the carboxy group taking place during or after the copolymerisation. The use of this process principle has been described by the inventor of the present invention in the following Patent Specifications: German Offenlegungsschrift 2,054,231, Swiss Patent Specification 523,961, German Offenlegungsschrift 2,021,141, German Patent Specification 2,626,900, German Auslegeschrift 2,603,259, German Auslegeschrift 2,659,853, Swiss Patent Specification 519,532, German Offenlegungsschrift 2,515,705, German Offenlegungsschrift 2,603,624, German Offenlegungsschrift 2,618,809 and German Offen legungsschrift 2,065,770.

The disadvantage of these known processes on an industrial scale is that relatively long reaction times (12 to 15 hours) are required for the reactions, that is to say esterification and copolymerisation, to go to completion. With these long reaction times, undesired side reactions take place, since the carboxyl group of the a,p-unsaturated monocarboxylic acid reacts, before and after its copolymerisation with the other monomers, with reactive groups, for example with the hydroxyl groups and/or glycidyl groups, with the formation of an ester, and the glycidyl groups react with one another or with the hydroxyl groups, to form structures containing an ether bond.Reaction batches of this type are therefore very sensitive to the conditions under which the reaction is carried out, so that on an industrial scale it is necessary to adhere very precisely to the reaction parameters in order reliably to manufacture copolymers with the desired characteristics in comparable quality. Moreover, even when the reaction is carried out very carefully, the formation of gel particles with particle diameters of about 5 to 25 Fwm always takes place to a certain extent; specialists in the lacquer field term these particles "specks" in the lacquer films produced from such lacquers, and the particles make it impossible to obtain a high quality lacquer coating.

German Offenlegungsschrift 1,668,510 also describes a processforthe manufacture of esterified polyhydroxy copolymers, but in this process the addition reaction between the epoxy groups and the carboxy groups is carried out before, after or during the copolymerisation. In the case of the embodiment in which the esterification is carried out during or after the copolymerisation, what has already been stated above applies and the process has the indicated disadvantages.In the case of the embodiment in which the two reactants, that is to say, the a,ss-unsaturated monocarboxylic acid and the epoxy compound, which is a glycidyl ester of a tertiary aliphatic monocarboxylic acid, are first processed on their own, in the absence of esterification catalysts, to give a precursor in the form of an ester (as is also carried out in German Patent Specifications 2,709,784 and 2,709,782), the surprising disadvantage which results is that the copolymer solutions are obtained as turbid solutions and the lacquer films produced therefrom are likewise cloudy.

Furthermore, further difficulties can very easily arise because the a,ss-unsaturated carboxylic acid tends to undergo self-polymerisation and, as a result of this, the homopolymers formed likewise cause turbidity.

Such findings are also confirmed by the statements in column 9, line 43 to column 10, line 8 of German Patent Specification 1,038,754 and in column 10, lines 1 to 39 of German Patent Specification 2,626,900.

The object of the present invention is substantially to eliminate the disadvantages, described above, of the known processes of the abovementioned type, some of which are carried out on an industrial scale, that is to say: 1. The copolymer solutions should be colourless and clear. This means that the lacquer films produced therefrom should also be "speck-free" or have a very "low speck content" and should not yellow, despite the presence of the catalyst.

2. Even on an industrial scale, the reaction conditions should be relatively non-critical for the manufacturing process, so that, after the optimum reaction parameters have been determsined, usable copolymers capable of high performance are always obtained even if there are small deviations in the reaction conditions, and undesired side reactions should also be very extensively eliminated by the catalyst, during copolymerisation and during use of the copolymers.

3. It should be possible to carry out the manufacturing process, especially on an industrial scale, by the one-pot process with a considerably shortened reaction time, in order thus to effect a quite substantial increase in the productivity of the production unit, as a result of the considerably shorter time for which the kettle is in use, and thus to lower production costs.

4. The manufacturing process should also permit the manufacture of improved copolymers based on a known or novel monomer composition.

5. The copolymers manufactured by the process should give non-tacky, water-resistant and elastic films on very diverse substrates or be suitable as binders for pigments, finishing paints and fleeces and also should be suitable for use as binder components, the coatings or sheet-like structures produced therewith having advantageous characteristics of various types.

The object of the invention has been achieved by carrying out the esterification stage in a special manner in the presence of a catalyst, the copolymerisation then taking place under specific conditions, without the esterification catalyst having an adverse effect on this reaction.

The invention relates to a process for the manufacture of copolymers which are based on vinyl compounds, a,p-unsaturated monocarboxylic acids and monoglycidyl compounds, carry hydroxyl groups and are soluble in organic solvents and in which the carboxyl group of the a,ss-unsaturated monocarboxylic acid is bonded to the monoglycidyl compound as an ester, by heating and esterifying in the presence of esterification catalysts, and copolymerisation by means of polymerisation initiators and, if desired, chain stoppers, characterised in that first the a,ss-unsaturated monocarboxylic acid is esterified with the monoglycidyl compound in the presence of at least one vinyl compound and at least one esterification catalyst based on an alkali metal compound and the copolymerisation is then carried out in the presence of inert solvents, a further vinyl compound or further vinyl compounds optionally being added before or during the copolymerisation, the proviso being that at least two further vinyl compounds must be present, in addition to the monomeric esterification product, in the reaction batch when carrying out the copolymerisation stage.

The a-p-ethylenically unsaturated monocarboxylic acids used are acrylic acid, methacrylic acid and/or crotonic acid, on their own or in a mixture. In addition, half-esters of maleic acid and fumaric acid with saturated alcohols which contain 1 to 10 carbon atoms are also suitable.

The monoepoxides include substituted alkyl compounds and also ethers and esters, if these contain a three-membered epoxide ring.

Examples of monoepoxides substituted by alkyl are propylene oxide, but-2-ene oxide, hex-2-ene oxide, oct-2-ene oxide and styrene oxide.

Examples of substituted ether,monoepoxides are butyl glycidyl ether, hexyl glycidyl ether, octyl glycidyl ether and phenyl glycidyl ether.

Examples of ester monoepoxides are the glycidyl esters of the following acids: acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, 2-ethyl-hexanoic acid, isononanoic acid and a,a-dialkylalkanemonocarboxylic acids in which the hydrogen atoms of the alkanemonocarboxylic acid which are in the a-position relative to the carboxyl group are replaced by alkyl radicals, so that there is a tertiary carbon atom having the formula

in which R1, R1, R2 and R3 denote alkyl groups, the total sum of the carbon atoms of all the alkyl groups being 3 to 25. The g lycidyl esters of a,a-dialkylalkane-monocarboxylic acids having 9 C atoms to 13 C atoms in the radical containing the alkyl groups are preferred.

The most preferred glycidyl ester of a n sa-dia an a,a-dialkylalkanemonocarboxylic acid has the empirical formula C13H2403.

Vinyl compounds which can be used are the aromatic vinyl compounds, for example styrene, vinyl-toluene, a-methylstyrene and halogenostyrene, which, apart from the vinyl group, do not possess any group capable of reaction with the carboxyl group.

Vinyl compounds which can be used are the esters of acrylic, methacrylic and crotonic acid with saturated alcohols which contain 1 to 10 carbon atoms in the alcohol radical, such as, for example, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, amyl, hexyl, heptyl, octyl, nonyl and decyl radicals, on their own or as a mixture.

Examples of vinyl esters which can be used are: vinyl esters of a,a-dialkylalkanemonocarboxylic acids having the formula

in which R1, R2 and R3 denote alkyl groups and the total sum of the carbon atoms in all alkyl groups is 3 to 25, and amongst these compounds vinyl esters having the following empirical formula CgH19-CO-O-CH=CH2 are preferred. Vinyl acetate and vinyl propionate can also be used as vinyl esters.

a,ss-Ethylenically unsaturated compounds carrying hydroxyl groups which can be used are hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and also butanediol monoacrylate and/or butanediol monomethacrylate, on their own or as a mixture. Furthermore, ether-esters carrying hydroxyl groups, such as polypropylene glycol monomethacrylate and/or polyethylene glycol monomethacrylate with average molecular weights of between about 175 and about 390, can also be used.

The special procedure for carrying out ester formation by means of the addition reaction is first described.

In the most common procedure, the a,ss-unsaturated monocarboxylic acid is reacted with the monoglycidyl compound in the presence of at least one other vinyl compound, by heating to 80 to 185"C, by means of a 1:1 addition reaction between the carboxyl group and the monoepoxy group to form the ester. If desired, a polymerisation inhibitor is also used. With this procedure it is preferred to carry out the reaction with the a,ss-unsaturated monocarboxylic acid in a range which extends from an amount which is very slightly less than the equivalent amount up to the equivalent amount, the molar ratio of monoepoxide: a,ss-unsaturated monocarboxylic acid being 1 0.98 to 1.

The esterification catalysts, based on an alkali metal compound, which can be employed are all sodium, lithium, potassium, rubidium and caesium compounds - on their own or in a mixture - which are soluble in the reaction mixture consisting of the a,ss-unsaturated monocarboxylic acid, the monoglycidyl compound and at least one further vinyl compound or at least go into solution when they are added and/or when the reaction batch is kept at the reaction temperature; however, the alkali metal compound employed should be free from those constituents which can have an adverse effect during the further processing of the addition product, which is an ester.

Examples of compounds which can be used are the carbonates, bicarbonates and formates and the hydroxides of the abovementioned alkali metals.

On an industrial scale, lithium hydroxide and potassium hydroxide - on their own or as a mixture - have proved most suitable.

For use on an industrial scale, potassium hydroxide is particularly advantageously employed, because of the inexpensive price and the outstanding catalyst characteristics. Appropriately, the alkali metal hydroxide employed, or the alkali metal compound or mixtures of alkali metal compounds employed, is dissolved in the a, p-unsaturated monocarboxylic acid to be esterified.However, it is also possible first to manufacture the alkali metal salt of the a, ss-unsaturated monocarboxylic acid, for use as the catalyst, from the alkali metal compound, for example alkali metal hydroxides, alkali metal carbonates or alkali metal bicarbonates, and the said acid and then to dissolve the alkali metal salt of the a, ss-unsaturated carboxylic acid in the reaction mixture or to bring the said salt into solution by heating, whilst carrying out the addition reaction.

In general, it suffices to add from about 0.005% by weight to about 0.5% by weight of an alkali metal compound of the type already mentioned, the % by weight being based on the alkali metal content of the compound employed, based on the weight of the ester-forming component, for the addition reaction.

Preferably, however, about 0.01% by weight to about 0.3% by weight of the alkali metal compound is added.

The most preferred range for the addition is about 0.02% by weight to about 0.1% by weight of alkali metal compounds, and amongst the alkali metal compounds, potassium compounds and lithium compounds are then very particularly advantageously used.

In a more preferred embodiment of the addition reaction, the procedure is as already described, but an inert organic solvent, or a mixture of inert organic solvents, is additionally used and the addition reaction is preferably carried out in the temperature range of 100 to 180"C. Inert solvents which can be used are those which do not contain any active hydrogen atoms, for example toluene, xylene or other aromatic compounds with a boiling range of about 100 C to about 180"C, butyl acetate, monoglycol ether-acetates, for example ethylglycol acetate, or mixtures of monoglycol acetate and xylene, examples of monoglycol acetates which may be mentioned being methylglycol acetate, ethylglycol acetate, isopropylglycol acetate or n-butylglycol acetate.When this preferred embodiment is carried out, the inert organic solvents can be employed in two to four times the amount by weight, based on the weight of the monoepoxide compound.

In a more specific embodiment of the above preferred addition process for the manufacture of the ester, the reaction is carried out with the use of organic solvents and the proportions of the total monomers employed are so chosen that 50 to 95 per cent by weight of addition product are formed in the reaction batch intended for the addition reaction, and 5 to 50 per cent by weight (preferably 5 to 20 per cent by weight) of another monomeric vinyl compound, or several other monomeric vinyl compounds, are present.

Surprisingly, the presence of the other monomeric vinyl compounds during the manufacture of the addition product prevents troublesome homopolymerisation of the addition product, as special investigations carried out by the Applicant Company have shown.

If copolymers with low average molecular weights of about 10,000 to about 20,000 are to be manufactured in the subsequent copolymerisation stage, the addition reaction must be carried out in the range indicated above and, in addition, chain regulators should be present in the reaction batch before and during the addition reaction.

If, however, copolymers with higher average molecular weights of about 20,000 to about 100,000 are to be manufactured in the subsequent copolymerisation stage, the addition reaction is carried out in the presence of all the vinyl compounds capable of polymerisation reactions, in the absence of chain regulators.

In all variants of the procedure for carrying out the addition reaction, the formation of the addition product is monitored analytically and as soon as acid numbers of about 3 to about 20 are obtained the addition reaction is regarded as ended if the addition product is copolymerised to copolymers which contain hydroxyl groups and are intended for crosslinking with polyisocyanates.

The above statements show that the conditions chosen in respect of the type and amount of the other vinyl compounds when carrying out the addition reaction (before the copolymerisation) and also the presence or absence of chain regulators exert a considerable influence on the characteristics of the copolymers to be manufactured in the subsequent copolymerisation stage. A possibility of this type for already controlling at the addition reaction stage the characteristics for the subsequent copolymerisation stage has not been disclosed hitherto for the monomer mixture in question and thus permits the manufacture of copolymers with a known or novel monomer composition with improved characteristics.

Further possibilities for variation of this principle will also be explained and illustrated by examples.

After the addition product of the a-ss-unsaturated monocarboxylic acid and the monoepoxide compound has been manufactured in the presence of at least one vinyl compound, the copolymerisation can take place, if desired after adjusting the monomer composition or after feeding in further monomers and polymerisation initiators and, if desired, chain regulators.

In a preferred embodiment, the abovementioned addition product is manufactured in the presence of an inert solvent or solvent mixture (for example xylene and ethylglycol acetate) in the presence of several (for example four) other monomeric vinyl compounds and a chain regulator, under reflux in the course of 2 hours. The polymerisation reaction can be carried out by continuing to keep the batch of the addition product, with the vinyl compounds contained therein, under reflux and adding a mixture of the requisite further amount of vinyl monomers and polymerisation initiators in small portions in the course of 1 to 6 hours and copolymerising. Preferred embodiments of this type are illustrated by Example 1.

In another preferred em bodiment the abovementioned addition product is manufactured, in the manner just explained, and kept under reflux and a mixture of the requisite further amount of vinyl monomers, chain stoppers and polymerisation initiators is added in small portions in the course of 2 to 4 hours and the resulting mixture is copolymerised and further copolymerised for about 2 to 6 hours. This procedure is distinguished by the addition of chain regulators to the batch containing the addition product and by the addition of chain regulators in the feed of the further vinyl monomers during the copolymerisation. This embodiment is illustrated by Examples 2,4 and 5.

In a further preferred embodiment the addition product is manufactured as indicated above but in the absence of a chain regulator; however, the feed of the further vinyl monomers contains a chain regulator. In this case the feed is added to the reaction batch in the course of 2 to 6 hours and the resulting batch is then further copolymerised for a further 1 to 6 hours. A procedure of this type is illustrated in Example 3.

Polymerisation initiators which can be employed are, for example,-a diacyl peroxide, for example dibenzyl peroxide, peresters, for example tertiary butyl peroctoate, and dialkyl peroxides, for example di-tert.-butyl peroxide, and also all peroxides which have half-lives in a temperature range of 50 to 150"C.

The proportion of peroxide is about 0.5 to 5% by weight, based on the total proportion of the a,ss-ethylenically unsaturated monomers, including the esterified monoepoxides.

The chain regulators optionally employed are, for example, octylmercaptan, decylmercaptan, laurylmercaptan and the branched dodecylmercaptan. The proportion of chain regulators, based on the total proportion of the ethylenically unsaturated monomers, including the esterified monoepoxides, is0 to 2.5% by weight.

As soon as 95 to 100% of the addition product have been manufactured, the feed of the polymerisation initiator and/or the mixture of the remaining a,ss-ethylenically unsaturated monomers and the polymerisation initiator and, if desired, chain regulator is started. The feed times are in general 15 minutes to 5 hours.

After this feed has ended, the reaction batch is kept under reflux for a further 2 to 3 hours until the copolymerisation reaction has gone to completion.

The invention is illustrated by the following examples but is not intended to be restricted to these examples: Example 1 A mixture consisting of 294 g of xylene, 150 g of ethylglycol acetate and 160 g of the glycidyl ester of an a,a-dialkylalkanemonocarboxylic acid of the following empirical formula C13H2403 with an epoxide equivalent of 245 to 253 (boiling range 5% - 90% at 760 mm Hug, 251" - 278"C) (= 24.3% by weight = 0.64 epoxide equivalent). (The glycidyl ester is described in "Technical bulletin RES/CAX/1"from Shell Chemicals under the title: "Shell Resin Intermediates Cardura E 10".Its structure can be represented by the following formula, which is based on a synthetic, saturated, highly branched monocarboxylic acid having 10 C atoms

in which R1, R2 and R3 represent straight-chain alkyl groups, at least one of which is always a methyl group), and 0.1 g of potassium hydroxide, dissolved in 46 g of acrylic acid (= 6.99% by weight = 0.638 equivalent), 5 g of propylene glycol monomethacrylate with an average molecular weight of 350 - 387 and a hydroxyl number of 145 - 160 (= 0.76% by weight) (the product can be represented by the following formula

in which n denotes numerical values of 5 or 6), 29 g (= 4,4% by weight) of hydroxyethyl methacrylate, 47.6 g (= 7.23% by weight) of styrene, 31.5 g (= 4.78% by weight) of methyl methacrylate and 7.4 of dodecylmercaptan is kept under reflux at 140 to 146"C in a reaction vessel fitted with a stirrer, a reflux condenser and a thermometer, for three hours until an acid number of 14.7 is obtained, in order to form the addition product. The calculated value is given by the sum of the monomers employed, that is to say glycidyl ester, acrylic acid, polypropylene glycol monomethacrylate, hydroxyethyl methacrylate, styrene and methyl methacrylate. The value obtained is 41.8% by weight.

After the preparation of the addition product has taken place, the following mixture, which is at room temperature in a dropping funnel and consists of 14.6 g (= 2.22% by weight) of polypropylene glycol monomethacrylate of the type mentioned above, 87.2 g (= 13.25% by weight) of hydroxyethyl methacrylate, 142.8 g (= 21.7% by weight) of styrene, 94.5 g (= 14.36% by weight) of methyl methacrylate, 7.4 g of di-tert.-butyl peroxide and 2.0 g of dodecylmercaptan, is added dropwise at a uniform rate, in the course of two hours, to the mixture which is still 140 to 142"C and the resulting mixture is then copolymerised for a further 2 hours in addition, by heating under reflux.

The resulting solution of the copolymer containing hydroxyl groups has a solids content of 62.5% by weight and a viscosity of 115 seconds, measured at 20"C in a flow cup with a 4 mm outlet nozzle, the copolymer solution having first been diluted to a concentration of 50% by weight with xylene. The acid number of the copolymer is 4.5.

In this Example 1, the reaction of 160 g of glycidyl ester and 46 g of acrylic acid to give the addition product is carried out in the presence of 5 g of propylene glycol monomethacrylate, 29 g of hydroxyethyl methacrylate, 97.6 g of styrene and 31.5 g of methyl methacrylate, the ratio of the additional produce to the other vinyl monomers being 64.55% by weight to 35.45% by weight. In addition, the formation of the monomeric addition product is carried out in the presence of tertiary dodecylmercaptan.

Further investigations have shown that the process illustrated above can be carried out as a one-pot process on an industrial scale, in which case about 3 hours are required for formation of the addition product and about 4 hours are required for formation of the copolymer, so that the total manufacturing time at the boil is only about 7 hours.

Example 1 The procedure is as indicated in Example 1, except that the following reactants are employed: 294.0 g of xylene, 150.0 g of ethylglycol acetate, 160.0 g of the g lycidyl ester of an a,a-dialkylalkane-monocarboxylic acid of the type mentioned in Example 1 (= 24.35% by weight = 0.64 epoxide equivalent) and 0.3 g of lithium hydroxide, dissolved in 45.0 g of acrylic acid (= 6.85% by weight = 0.625 acid equivalent), 47.6 g (= 7.24% by weight) of styrene, 31.5 g (= 4.79% by weight) of methyl methacrylate and 7.5 of dodecyl mercaptan are reacted for about 3 hours at about 144"C until an acid number of 11 is obtained, to give the addition product, the reaction being carried out as described in Example 1 but the calculated value in this case being 39% by weight, and the following mixture, which is at room temperature and consists of 20.0 g (= 3.04% by weight) of polypropylene glycol monomethacrylate, as described in Example 1, 116.0 g (= 17.65% by weight) of hydroxyethyl methacrylate, 142.6 g (= 21.7% by weight) of styrene, 94.5 g (= 14.38% by weight) of methyl methacrylate, 2.0 g of dodecylmercaptan and 7.5 g of di-tert.-butyl peroxide, is added dropwise at a uniform rate in the course of 3 hours, and the resulting mixture is then copolymerised for about a further 2 hours at the same temperature. The resulting copolymer solution has a solids content of 61.1% by weight an an acid number of 3.1, based on the solids content.The flow time measured when determining the viscosity of a copolymer solution previously diluted to 50% by weight with xylene is 118 seconds at 20"c, the measurement being carried out in a flow cup with an outlet nozzle 4 mm in diameter.

In this Example 2,205 g of monomeric addition product are prepared in the first stage, from the glycidyl ester and acrylic acid in the presence of 47.6 g of styrene and 31.5 g of methyl methacrylate. The ratio of addition product to the other monomers is 72.15% by weight to 27.85% by weight. A small amount of dodecylmercaptan is present during the preparation of the addition product. During the preparation of the copolymer, the monomer feed likewise contains dodecylmercaptan. The above example can also be carried out as a one-pot process on the industrial scale, the total boiling time being about 7 hours.

Example 3 The procedure is as indicated in Example 1, except that the following reactants are employed: 294.0 g of xylene, 150.0 g of ethylg lycol acetate, 160.0 g of the g lycidyl ester of an a,a-dialkylalkane-monocarboxylic acid (= 24.1% by weight = 0.64 epoxide equivalent) of the type mentioned in Example 1, and 0.3 g of lithium hydroxide, dissolved in 46.0 g of acrylic acid (= 6.98% by weight = 0.638 acid equivalent), 20.0 g (= 3.04% by weight) of styrene, 12.0 g (= 1.82% by weight) of methyl methacrylate and 7.4 g of dodecylmercaptan are esterified for about 3 hours at 144"C until an acid number of 14 is obtained, as described in Example 1.In this case the calculation for the determination of the acid number is based on a solids content of 34.9. 19.6 g (= 2.97% by weight) of polypropylene glycol monomethacrylate, as described in Example 1, 116.2 g (= 17.65% by weight) of hydroxyethyl methacrylate, 170.4 g (= 25.88% by weight) of styrene,114.0 g (= 17.32% by weight) of methyl methacrylate, 2.0 g of dodecylmercaptan and 6.4 g of di-tert.-butyl peroxide are added dropwise at a uniform rate in the course of 3 hours at 1460C and the resulting mixture is then copolymerised for a further 2.5 hours at the same temperature. The copolymer solution has a solids content of 61.6% by weight and an acid number of 3.9.The flow time measured when determining the viscosity of a solution previously diluted to 50% by weight with xylene is 135 seconds, measured at 20 C in a flow cup with a 4 mm outlet nozzle.

In this example 206 g of monomeric addition product are prepared from the glycidyl ester and acrylic acid in the presence of 20 g of styrene and 12 g of methyl methacrylate. The ratio of the addition product to the four other vinyl monomers is 86.55% by weight to 13.45% by weight. The preparation of the addition product was carried out in the absence of dodecylmercaptan.

Example 4 The procedure is as indicated in Example 1, except that the following reactants are employed: 294.0 g of xylene, 150.0 g of ethylglycol acetate, 155.0 g of the glycidyl ester of an a.a-dialkylalkane-monocarboxylic acid (= 23.5% by weight = 0.627 epoxide equivalent) of the type described in Example 1, and 0.2 g of lithium hydroxide, dissolved in 45.0 g of acrylic acid (6.82% by weight = 0.625 acid equivalent), 12.0 g of methyl methacrylate, 25.0 g (= 3.79% by weight) of styrene and 7.4 g of dodecylmercaptan are reacted for 3 hours at about 145"C until an acid number of 11 is obtained, to give the addition product, as described in Example 1, and the following mixture, which is at room temperature and consists of 142.6 g (= 21.63% by weight) of hydroxyethyl methacrylate, 133.2 g (= 20.21% by weight) of styrene, 146.2 g (= 24% by weight) of methyl methacrylate, 6.7 g of di-tert.-butyl peroxide and 2.0 g of dodecylmercaptan is added at a uniform rate in the course of 3 hours at about 146"C and the resulting mixture is then copolymerised for a further 2.5 hours at the same temperature.

The copolymer solution has a solids content of 60.5% and an acid number of 4.5. The flow time measured when determining the viscosity of a solution previously diluted to 50% by weight with xylene is 150 seconds, measured at 20"C in a flow cup with a 4 mm outlet nozzle, In this example 200 g of monomeric addition product are prepared from the glycidyl ester and acrylic acid in the presence of 25 g of styrene and 12 g of methyl methacrylate. The ratio of the addition product to styrene is 84.38% by weight to 15.62% by weight. The preparation of the addition product was carried out in the presence of dodecylmercaptan. In addition, the feed of the monomer mixture for the copolymerisation reaction contained dodecylmercaptan.

Example 5 The procedure is as indicated in Example 1, except that the following reactants are employed: 400.0 g of xylene, 209.0 g of the glycidyl ester of an a,a-dialkyalkanemonocarboxylic acid of the type mentioned in Example 1 (= 34.83% by weight = 0.853 epoxide equivalent) and 0.2 g of potassium hydroxide, dissolved in 61.0 g of acrylic acid (= 10.16% by weight = 0.847 acid equivalent), 40.0 g (= 6.66% by weight) of styrene, 40.0 g (= 6.66% by weight) of butyl acrylate and 0.7 g of dodecylmercaptan.The mixture was reacted in the manner described in Example 1, for 2 hours at 1420C until an acid number of 6.0 was obtained, to give the addition product, and the following mixture, which was at room temperature and consisted of 125.0 g (= 20.83% by weight) of styrene, 125.0 g (= 20.83% by weight) of butyl acrylate, 5.0 g of dodecylmercaptan and 6.5 g of di-tert.-butyl peroxide, was added dropwise at a uniform rate in the course of 2 hours and the resulting mixture was then polymerised at 143"C for 2.5 hours. The copolymer solution has a solids content of 60% by weight and an acid number of 3. The flow time measured when determining the viscosity of a solution previously diluted to 50% with xylene is 60 seconds, measured at 20"C in a flow cup with a 4 mm outlet nozzle.

In this example 270 g of addition product are prepared from the glycidyl ester and acrylic acid in the presence of 50 g styrene and 50 g of butyl acrylate. The ratio of the addition product to the styrene and butyl acrylate is 77.14% by weight to 22.86% by weight.

Example 6 Preparation of a reactive lacquer: The viscosity of 100 parts by weight of copolymer solution from Example 2 and 40 parts by weight of a 75% strength solution of an aliphatic triisocyanate which contains biuret groups, has been obtained by reacting 3 mols of hexamethylene diisocyanate with one mol of water and has a NCO content of 21% by weight, dissolved in 1:1 xylene/ethylglycol acetate, is adjusted to give a flow time of 18 seconds, measured at 20"C in a DIN cup with a 4 mm outlet nozzle, using a solvent mixture consisting of 1 1 xylene and butyl acetate.

Example 7 The procedure is as indicated in Example 1, except that the following reactants are employed: 294.0% of xylene, 150.0g of ethylglycol acetate,150.0 of phenyl glycidyl ether(= 22.79% by weight = 1 epoxide equivalent) and 0.2 g of lithium hydroxide dissolved in 72.0 g of acrylic acid (= 10.93% by weight = 1 acid equivalent), 60.0 g (= 9.12% by weight) of styrene, 60.0 g (= 9.12% by weight) of n-butyl acrylate and 5.0 g of dodecylmercaptan.

The mixture was reacted for 3 hours at 146DC to give the addition product with an acid number of 75 and the following mixture of 185.1 g (= 24.02% by weight) of styrene, 158.1 g (= 24.02% by weight) of n-butyl acrylate, 2.0 g of dodecylmercaptan and 6.5 g of di4ert.-butyl peroxide was then added dropwise at a uniform rate in the course of three hours and the resulting mixture was then copolymerised for three hours at 145"c. The copolymer solution has a viscosity of 470 seconds flow time, measured at 20"C in a flow cup with a 4 mm nozzle. The finished copolymer has an acid number of 36.

Example 8 Preparation of a stoving lacquer: 100 parts by weight of the copolymer solution obtained according to Example 7 were mixed cold with 45 parts by weight of a solution, containing 50% solids, of a melamine/formaldehyde resin etherified with butanol and the mixture was applied to iron sheets to give a dry film coating thickness of 50 m and the coatings were stoved for 30 minutes at 1 200C. Clear films, which have a hard surface, are stable to xylene and also display good adhesion and flexibility were obtained.

Example 9 The procedure was as indicated in Example 7, except that 130 g of n-butyl glycidyl ether were employed in place of phenyl glycidyl ether.

The resulting copolymer solution had a viscosity of 185 seconds flow time, measured at 20"C in a flow cup with a 4 mm nozzle.

Example 10 Preparation of a stoving lacquer 100 parts by weight of the copolymer solution obtained according to Example 9 were mixed cold with 45 parts by weight of a solution, containing 50% solids, of a urea-formaldehyde resin etherified with isobutanol and the mixture was applied to steel sheets to give a dry film coating thickness of 60 cm and the coatings were stoved for 30 minutes at 140"C. Clear films, which have a hard surface, are stable to xylene and also display good adhesion to very diverse metal substrates, such as aluminium and copper, were obtained.

Example 71 The procedure is as indicated in Example 1, except that the following reactants are employed: 290 g of xylene, 150 g of ethylglycol acetate, 178 g of clycidyl benzoate (= 27.04% by weight = 1 epoxide equivalent), 0.1 g of potassium hydroxide and 0.2 g of lithium hydroxide dissolved in 70 g of acrylic acid (= 10.85% by weight = 0.97 acid equivalent), 60 g (= 9.12% by weight) of styrene, 60 g (= 9.12% by weight) of n-butyl acrylate and 4 g of dodecylmercaptan.

The mixture was reacted for three hours at 145'C to give the addition product with an acid number of 48 and a mixture of 144.1 g (21.89% by weight) of styrene, 144.1 g (21.89% by weight) of n-butyl acrylate and 7.0 g of di-tert.-butyl peroxide was then added dropwise at a uniform rate in the course of three hours and the resulting mixture was then polymerised at 1460C. The copolymer solution has a viscosity of 285 seconds flow time, measured at 20"C in a flow cup with a 4 mm nozzle. The copolymer has a hydroxyl number of 85 and an acid number of 15.

Example 12 Preparation of a reactive lacquer: The viscosity of 100 g of copolymer solution, obtained according to Example 11, and 20 g of a 75% strength solution of an aliphatic triisocyanate which contains biuret groups, has been obtained by reacting three mols of hexamethylene diisocyanate with one mol of water and has a NCO content of 21% by weight, dissolved in 1:1 xylene/ethylglycol acetate, is adjusted to the spraying viscosity with a solvent mixture consisting of 1:1 xylene/butyl acetate and the resulting mixture is used to coat steel sheets to give a dry film coating thickness of 45 cm and the coatings are cured for 10 days at room temperature. The films have an excellent gloss and good stability towards xylene.

Example 13 The procedure was as indicated in Example 11, except that 128 g of oct-2-ene oxide were employed in place of glycidyl benzoate.

The resulting copolymer solution had a viscosity of 135 seconds flow time, measured at 20"C in a flow cup with a 4 mm nozzle.

Example 14 Preparation of a stoving lacquer: 100 parts by weight of the copolymer solution obtained according to Example 13 were mixed with 60 parts by weight of a solution, containing 50% solids, of a urea/formaldehyde resin etherified with isobutanol and the mixture was applied to steel sheets to give a dry film coating thickness of 50 um, and the coatings were stoved for 30 minutes at 1 50"c.

The copolymers obtainable by the process of the invention can be used as component A in reactive lacquers, together with a polyisocyanate component B.

Glossy films which are stable to xylene and super fuels and also have a high flexural strength were obtained.

Further advantageous embodiments of the invention are described in Patent Claims 1 to 23.

Polyisocynates which can be employed as component B are, for example, the following: toluylene 2,4-diisocyanate, toluylene 2,6-diisocyanate, cyclohexylene 1 ,4-diisocyanate, diphenylmethane 4,4'diisocyanate, naphthylene 1 ,5-diisocyanate, 1 -(isocyanatophenyl)-ethyl isocyanate or xylylene diisocyanate, fluorine-substituted diisocyanates, ethylene glycol diphenyl ether 2,2'-diisocyanate, diethylene glycol diphenyl ether2,2'-diisocyanate, l,l'-dinaphlthyl 2,2'-diisocyanate, biphenyl 2,4'-diisocyanate, biphenyl 4,4'-diisocyanate, benzophenone 3,3'-diisocyanate, fluorene 2,7-diisocyanate, anthraquinone 2,6diisocyanate, pyrene 3,8-diisocyanate, chrysene 2,8-diisocyanate, 1 -methylbenzene 2,4,6-triisocyanate, naphthalene 1 ,3,7-triisocyanate, biphenyl-methane 2,4,4'-triisocyanate, triphenylmethane 4,4',4"triisocyanate, 3'-methoxyhexane diisocyanate, octane diisocyanate, o,w-diisocyanato-l ,4-diethyl benzene, co,o-diisocyanato-l ,4-dimethylnaphthalene, cyclohexane 1 ,2-diisocyanate, 1 -isopropylbenzene 2,4 diisocyanate, 1 -chlorobenzene 2,4-diisocyanate, 1 -fluorobenzene 2,4-di-isocyanate, 1-nitrobenzene 2,4 diisocyanate, 1-chlorn-4-methoxybenzene 1,4-diisocyanate, azobenzene 4,4'-diiso-cyanate, benzeneazonaphthalene 4,4'-diisocyanate, diphenyl ether 2,4-diisocyanate and diphenyl ether 4,4'-diisocyanate and also polyisocyanates based on isophorone diisocyanate with isocyanurate structures and a functionality between 3and4.

Further compounds which may be mentioned are reaction products which contain isocyanate groups and are obtained from polyhydric alcohols and polyisocyanates, for example the reaction product of 1 mol of trimethylolpropane with 3 mols of toluylene diisocyanate, and also trimerised or polymerised isocyanates.

In addition, a reaction product which contains biuret groups and is obtained from 1 mol of water and 3 mols of hexamethylene diisocyanate and has a NCO content of 16 to 17 % by weight can also be used. The last-mentioned reaction product of water and hexamethylene diisocyanate is particularly preferred. The NCO content of the reaction product is that for a 75 % strength solution in xylene/ethylglycol acetate.

For use of the copolymers, the mixtures of solvent-containing copolymers A, which contain hydroxyl groups, and polyisocyanate B are applied by the simplest conceivable means, say after the addition of known auxiliaries, such as levelling agents, pigments or dyes, by spraying, dipping, coating, brushing or other suitable means, to the corresponding substrates and the sheet-like structure is dried at room temperature; in special cases, the coatings can be baked; this essentially depends on the substrates used and on the requirements which the coatings have to meet in practice. The additional use of reactive melamine resins can also be advantageous.The reactive melamine resins can be added, say, in amounts of 1 to 10 % by weight, based on the weight of the binder component, and as a result of this, in particular, an increase in the gloss of the sheet-like structure can be observed.

When the copolymers are used in the reactive lacquers already mentioned, the reaction and the application of the sheet-like structure to the substrate are carried out in solution. Suitable solvents are, for example, ethyl acetate, butyl acetate, ether-acetates, diethylglycol diacetate and also aromatic compounds, such as benzene, toluene or xylene. The concentration of the solutions can vary within wide limits and essentially depends on the solubility of the components. Solutions with a solids content of 20 to 80 % by weight are preferably used.

When the copolymers are used in reactive lacquers, components A and B are preferably used in the following amounts: (A) 60 to 95 % by weight of hydroxyl group-containing copolymers prepared according to the invention and (B) 5 to 40 % by weight of an organic polyisocyanate, the numerical values for (A) and (B) together having to add up to 100 % by weight.

A particularly preferred reactive lacquer contains: (A) 63 to 68% by weight of prepared copolymers containing hydroxyl groups and (B) 32 to 37% by weight of the organic triisocyanate which has been obtained by reacting 3 mols of hexamethylene diisocyanate with 1 mol of water, the numerical values for (A) and (B) having to add up to 100% by weight.

The main fields of application for the copolymers - in combination with aliphatic and aromatic polyisocyanates or mixtures thereof - are air-drying and oven-drying lacquer coatings on metal, wood and plastic. Two-component lacquers of this type are preferably used when the characteristics expected from the air-dried or force-dried lacquers are those which customarily are offered only by stoving lacquers.

These new reactive lacquers are employed as binders, especially for the car repair lacquer field and for lacquers for buses and lorries.

In combination with aliphatic polyisocyanates, yellowing-free lacquer coatings of good body and with excellent stability to weathering and gloss retention are obtaned.

A certain degree of yellowing must be expected when aromatic polyisocyanates are used for crosslinking.

In accordance with their higher crosslinking density, reactive lacquers on the basis of the invention display a high scratch-resistance and abrasion-resistance, coupled with good stability to solvents, compared with comparable good commercially available products for the same purpose.

The good stability to water and chemicals should also be singled out.

Lacquers of this type can not only be air-dried but can also be stoved within a wide temperature range; thus, for example, the films are completely cured in 30 minutes at 130"C.

The resistance to weathering of the lacquer coatings cured at room temperature is not inferior to that of the stoved films.

The copolymers have a high pigment pick-up. All neutral pigments and fillers are suitable for pigmenting.

Strongly basic pigments and also pigments with soluble metal compounds can exert a catalytic action on the crosslinking, as a result of which the processing time of the lacquer batches, after mixing, is shortened.

Tests on the reaction solution obtained according to Example 6, in order to demonstrate the technical advance achieved: 1. Determination of the pot life, that is to say the stability of the two-component lacquer at 20"C: Flow time in seconds (4 mm outlet nozzle) Start 18 after 24 hours 27 after48hours 70 after 50 hours 90 This result shows that these lacquers have a surprisingly long pot life. On the basis of the processing conditions customary in practice - rise in the viscosity to twice the initial viscosity, that is to say a flow time of at most 36 seconds - this lacquer has a processing time of more than 60 hours. Moreover, lacquer residues which are 96 hours old can be diluted by adding freshly made-up lacquer solutions and can still be processed well.

2. Determination of the curing time of the lacquer films: This manufactured two-component lacquer solution is applied to a glass plate in such a way that a dry film coating thickness of about 40 cm results.

2a Determination of the König pendulum hardness at 20"C: Pendulum hardness after one day 78 seconds after two days 120 seconds after three days 200 seconds The surprising feature in this case is that the clear lacquer has reached its virtually complete film hardness of more than 200 seconds after only a 3 day curing time at 20"C. If this result is compared with the two day open pot life, that is to say no gelling of the lacquer solution takes place within this period, this result was surprising and not foreseeable.

2b Determination of the König pendulum hardness after stoving at 80048C with a 30 minute stoving time: Pendulum hardness 80"C 30 minutes 120 seconds after one day at 20"C 150 seconds after two days at 20"C 200 seconds As a result of the 30 minute drying time at 80"C, the complete film hardness of 200 seconds pendulum hardness is obtained after only a further two days drying at 20oC.

The lacquer films resulting therefrom have a very high surface hardness and cannot be damaged by testing with a fingernail. Moreover, these coatings are distinguished by very good fastness to light and stability to solvents, such as xylene, toluene or acetone. When sheet metal samples placed facing south are subjected to weathering in Florida for 11/2 years at 5"C, these lacquer films display no cracking and the gloss is reduced by only 10% compared with the starting gloss, which is 110%, measured by the Lange method.

Comparison tests to demonstrate the technical advance achieved compared with the best, commercially available competitive products, in respect of the pot life: Copolymer according Analogous reactive Analogous to Example 2 of the lacquer, but co- reactive lacinvention - reactive polymer according quer, but lacquer according to to Example 2 of copolymer Example 6 of the German Patent according to invention Specification Example 1 of 2,603,259 German Patent Specification 2,626,900 Determination of the pot life of the reactive lacquer by measuring the flow time in a DIN cup with an outlet nozzle 4 mm in diameter, at 20"C in seconds Time at the start 18 18 18 after 24 hours 26 25 28 after 48 hours 72 75 155 after 56 hours 270 280 not measur able, gelled after 60 hours & not measurable, gelled Comparison tests to demonstrate the technical advance achieved compared with the best, commercially available competitive products, in respect of the pot life: In order to determined the pot life, the copolymers prepared according to the invention which are listed in the table above and, for comparison, the best commercially available competitive products were mixed with the aliphatic triisocyanate which had been obtained by reacting 3 mols of hexamethylene diisocyanate with 1 mol of water. The mixing ratios of the copolymers with the polyisocyanate were, based on the solids content, 70% by weight of copolymer: 30% by weight of polyisocyanate.The mixtures were diluted with a solvent mixture consisting of xylene/butyl acetate in a weight ration of 1:1 to a viscosity of 18 seconds flow time, measured in a DIN cup with a 4 mm outlet orifice, and the rise in viscosity was determined as a function of time at 200C. As can be seen from the above table, the copolymers prepared according to the invention are very similar to the known copolymers according to German Patent Specification 2,603,259 and German Patent Specification 2,626,900.

The copolymers, containing hydroxyl groups, which are obtainable according to the invention can also be used with blocked polyisocyanates, instead of with the polyisocyanates, for the manufacture of stoving lacquers, as is described, for example, in German Offenlegungsschrift 2,623,081 under the title "Stoving lacquers based on film-forming copolymers which contain hydroxyl groups and are soluble in inert organic solvents".Blocked polyisocyanates for this purpose have, for example, also been described by the inventor of the present invention in German Offenlegungsschrift and Auslegeschrift 2,612,786 under the title "Blocked diisocyanates, their manufacture from diisocyanatomethyl-norbornane and alkyl acetoacetates and their use as crosslinking agents", in German Offenlegungsschrift and Auslegeschrift 2,612,785 "Blocked diisocyanates, their manufacture from 4,4'-diisocyanato-dicyclohexylmethane and alkyl aceto-acetates and their use as crosslinking agents", in German Offenlegungsschrift and Auslegeschrift 2,612,784 "Blocked diisocyanates, their manufacture from hexamethylene 1,6-diisocyanate and acetoacetates and their use as crosslinking agents", in German Offenlegungsschrift and Auslegeschrift 2,612,783 "Blocked polyisocyanates obtained from biuret group-containing polyisocyanate and alkyl acetoacetates" and in German Offenlegungsschrift and Auslegeschrift 2,612,638 "Blocked diisocyanates obtained from 2,2,4-trimethylhexamethylene diisocyanate and alkyl acetoacetates and their use as crosslinking agents".

As, for example, Examples 8, 10 and 14 of the present invention show, 70 to 95% by weight of hydroxyl group-containing copolymers, manufactured according to the invention, can be used with 5 to 30% by weight of aminoplast resins as stoving lacquers, the % by weight data having to add up to 100% by weight.

Aminoplast resins which can be used are all aminoplast resins which are compatible with acrylate copolymer resins; these are available commercially in large numbers and frequently are synthesised on the basis of urea/formaldehyde and/or melamine/formaldehyde and are in the form of the products etherified with lower alkanols.

The solution of the finished copolymer is cooled and the aminoplast solution is introduced, the solvent content being so adjusted that the desired concentration is obtained. Pigments can then be added.

After stoving at 90 to 180"C, the stoving lacquers according to the invention give films which have excellent stability characteristics towards chemicals of all types, such as solvents, acids and alkalis and also super fuels.

The stoving lacquers can be dried at room temperatures. It is not essential that curing is carried out at 120 to 140"C over a period of 30 minutes. At 160"C, for example, the stoving time is reduced to about 15 minutes.

Preferred aminoplasts are condensation products of formaldehyde and melamine, about 4 to 6 mols of formaldehyde per mol of melamine having been reacted, either under weakly acid or under weakly basic conditions, and the products should be 80 to 100% etherified with butanol or isobutanol. The reaction products resulting therefrom should have a molecular weight of 400 to 1,200 and be soluble in organic solvents such as xylene and butanol or isobutanol and other alcohols.

The copolymer and the aminoplast are dissolved in a ratio of 70 to 95 parts of the copolymer and 5 to 30 parts of the aminoplast in the organic solvent. The ratios of the copolymer and of the alkylated aminoplast must be so chosen that the two components are compatible not only in the coating solution but also in the finished film. Any suitable concentration of the copolymer and of the aminoplast in the solvent, for example from 1 to 50 per cent by weight, can be used. If a pigment is present, the total solids content in the coating composition is between 5 and 75 per cent by weight. The ratio of pigment to binder (copolymer plus aminoplast) can be between 1: 20 and 1:1.

Solvents which can be used are: hydrocarbons, such as benzene, toluene, xylenes and aromatic naphthenes or mixtures of such solvents; esters, such as ethyl acetate, lactate or propionate, butyl acetate, lactate or propionate, amyl acetate, lactate or propionate, ethoxy-ethyl acetate, lactate or propionate or methoxyethyl acetate, lactate or propionate; ketones, such as acetone, methyl isopropyl ketone, methyl isobutyl ketone, dioxane, isophorone or cyclohexanone; alcohols, such as n-butanol, t-butanol, isopropyl alcohol, n-propyl alcohol, amyl alcohols and cyclohexanol; ethers, such as diethyl ether and the monoethyl, monomethyl and monobuty ethers of ethylene glycol, and various other solvents, such as dimethylformamide, dimethylacetamide, acetonitrile, nitromethane, nitroethane, nitropropane or nitrobutane, as well as mixtures of 2 or more solvents of the same group and also of several or all of the groups mentioned above.

Pigments which can be added are: inorganic pigments, such as Chrome Yellow, Prussian Blue and Brunswick Green; titanium pigments, for example titanium dioxide, extended titanium pigments (which are extended either with precipitated or natural extenders, such as alkaline earth metal sulphates, for example calcium sulphate and barium sulphate); shaded titanium pigments and titanates, such as the titanates of barium, zinc, lead and magnesium. Other types of organic pigments can also be used, for example zinc sulphide pigments, such as zinc sulphide, lithopone, extended zinc sulphide pigments, such as lithopone on a calcium base, zinc sulphide extended with natural extenders, zinc oxide or antimony oxide or organic pigments, that is to say organic dyes which are free from sulphonic acid groups, carboxylic acid groups or other groups conferring solubility in water. The term "pigment" also includes other water-insoluble organic dyes, for example the calcium or barium lacquers of azo dyes for lacquers.

The new stoving lacquers can be applied to the substrates in any desired manner, for example by spreading, spraying, dipping or rolling. They are then dried and cured by heating.

The calculation of reaction batches for the manufacture of copolymers with a specific hydroxyl group content has been described by the same inventor in columns 5 and 6 of German Auslegeschrift 2,603,259 and in columns 5 to 8 of German Auslegeschrift 2,626,900.

Claims (1)

1. Process for the manufacture of copolymers which are based on vinyl compounds, a,ss-unsaturated monocarboxylic acids and monoglycidyl compounds, carry hydroxyl groups and are soluble in organic solvents and in which the carboxyl group of the a,ss-unsaturated monocarboxylic acid is bonded to the monoglycidyl compound as an ester, by heating and esterifying in the presence of esterification catalysts, and copolymerisation by means of polymerisation initiators and, if desired, chain stoppers, characterised in that first the (x-ss-unsaturated monocarboxylic acid is esterified with the monoglycidyl compound in the presence of at least one vinyl compound and at least one esterification catalyst based on alkali metal compound and the copolymerisation is then carried out in the presence of inert solvents, a further vinyl compound or further vinyl compounds optionally being added before or during the copolymerisation, the proviso being that at least two further vinyl compounds must be present, in addition to the monomeric esterification product, in the reaction batch when carrying out the copolymerisation stage.

2. Process according to Claim 1, characterised in that first 2 to 50% by weight of addition product are manufactured by esterifying the a-p-unsaturated monocarboxylic acid with the monoglycidyl compound and then the reaction batch used to manufacture the addition product is copolymerised with 98 to 50% by weight of other vinyl compounds, the sum of the reactants having to add up to 100% by weight.

3. Process according to Claim 1 or 2, characterised in that first 2 to 50% by weight of addition product are manufactured by esterifying the a-ss-unsaturated monocarboxylic acid with the glycidyl compound and then the reaction batch used to manufacture the addition product is copolymerised with 98 to 50% by weight of other vinyl compounds, 0 to 30% by weight of which can be one or more vinyl compounds having a hydroxyl group in the molecule.

4. Process according to one of Claims 1 to 3, characterised in that styrene or acrylates and/or methacrylates having 1 to 12 carbon atoms in the alcohol radical are employed as other vinyl compounds.

5. Process according to one of Claims 1 to 4, characterised in that the compounds employed as other vinyl compounds containing a hydroxyl group in the molecule are hydroxyethyl acrylate, hydroxypropyl acrylate, butanediol monoacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, butanediol monomethacrylate, polypropylene glycol monomethacrylate and/or polyethylene blycol monomethacrylate with average molecular weights of between about 175 and about 390.

6. Process according to one of Claims 1 to 5, characterised in that first 10 to 40% by weight of addition product are manufactured by esterifying acrylic acid and/or methacrylic acid with a monoglycidyl ester, or mixture of monoglycidyl esters, of aliphatic, saturated monocarboxylic acids having 2 to 19 carbon atoms in the presence of a mixture of 30 to 88% by weight of styrene, vinyl esters of saturated monocarboxylic acids, or mixtures of such esters, having 4 to 19 carbon atoms in the carboxylic acid molecule, ethyl acrylate, n-butyl acrylate, iso-butyl acrylate, sec.-butyl acrylate, tert.-butyl acrylate, methyl acrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec.-butyl methacrylate, tert.-butyl methacrylate and/or methyl methacrylate and 2 to 30% by weight of hydroxyethyl acrylate, hydroxy-propyl acrylate, butanediol monoacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and/or butanediol monomethacrylate and the reaction batch is the copolised, the percentages by weight mentioned above having to add up to 100% by weight.

7. Process according to one of Claims 1 to 6, characterised in that first 6 to 12% by weight of acrylic acid are esterified with 18 to 39% by weight of the glycidyl ester of an a-a-dialkylalkanemonocarboxylic acid which has the empirical formula C13H2403 and the structure of which approximately corresponds to

in which R1, R2 and R3 represent straight-chain alkyl groups, at least one of which is a methyl group, to give the addition product with acid numbers of 15 to 22, the molar ratio of glycidyl ester to acrylic acid being 1::0.98 to 1, and then the resulting reaction batch is reacted with 30 to 15% by weight of styrene and or vinyl-toluene, 15 to 25% by weight of methyl methacrylate and 15 to 25% by weight of hydroxyethyl methacrylate and the reaction is continued until an acid number of 6 to 9 is obtained, the given percentages by weight having to add up to 100% by weight.

8. Process according to one of Claims 1 to 6, characterised in that first5 to 7% by weight of acrylic acid are esterified with 17 to 25% by weight of the glycidyl ester of an α-α-dialkylalkanem o n oca an a-a-dialkylalkanemonocarboxylic acid which has the empirical formula C13H24O3 and the structure of which approximately corresponds to

in which R1, R2 and R3 represent straight-chain alkyl groups, at least one of which is a methyl group, to give the addition product with acid numbers of up to 18 + 1, the molar ratio of glycidyl ester to acrylic acid being 1::0.98 to 1, and then the resulting reaction batch is copolymerised with 25 to 30% by weight of styrene, 15 to 20% by weight of methyl methacrylate, 15 to 20% by weight of hydroxyethyl methacrylate, 2 to 6% by weight of polypropylene glycol monomethacrylate, which has a structure which approximately corresponds to the formula

in which n denotes numbers of 5 to 6, and an average molecular weight of about 350 to 387, and 10 to 3% by weight of the vinyl ester of an a-a-dialkylalkane-monocarboxylic acid which has the approximate formula C9H1s-CO-O-CH=CH2, in which the grouping C9H19 largely has the structure

the percentages by weight having to add up to 100% by weight and the copolymerisation being continued until acid numbers of 6 to 7 are obtained.

9. Process according to one or more of Claims 1 to 8, characterised in that the addition reaction of the a-p-unsaturated monocarboxylic acid with the monoglycidyl compound is carried out in the presence of 5 to 70% by weight of another vinyl compound or of other vinyl compounds, the percentages by weight of the components for the addition product and the other vinyl compound or compounds having to add up to 100% by weight and the further requisite amount of vinyl compounds being added during the copolymerisation reaction, so that, at the end of the copolymerisation reaction, 2 to 50% by weight of addition product and 98 to 50% by weight of other vinyl compounds are in the form of a copolymer.

10. Process according to one of Claims 1 to 9, characterised in that the reaction of the a-a-unsaturated monocarboxylic acid with the monoglycidyl compound to give the monomeric addition product is carried out in the presence of at least one inert organic solvent, which does not contain any active hydrogen atoms, by heating to the reflux temperature.

11. Process according to one of Claims 1 to 10, characterised in that the reaction of the a,-unsaturated monocarboxylic acid with the monoglycidyl compound to give the monomeric addition product is carried out in the presence of a chain regulator.

12. Process according to one of Claims 1 to 10, characterised in that the copolymerisation is effected by heating the reaction batch, which contains the monomeric addition product formed, in the presence of inert organic solvents, which do not contain any active hydrogen atoms, to the reflux temperature in the presence of polymerisation initiators.

13. Process according to one of Claims 1 to 12, characterised in that the copolymerisation is effected by heating the reaction batch, which contains the monomeric addition product fbrmed, in the presence of inert organic solvents, which do not contain any active hydrogen atoms, under reflux and with the addition of polymerisation initiator and vinyl compounds and, after all the components have been added, the reaction batch is further heated until the copolymerisation has ended.

14. Process according to one of Claims 1 to 13, characterised in that the copolymerisation is carried out with the addition of a chain regulator.

15. Reactive lacquers based on copolymers, which are based on vinyl compounds, a- & nsaturated monocarboxylic acids and monoglycidyl compounds, the two latter being bonded as esters by an addition reaction, and carry hydroxyl groups, polyisocyanates, inert organic solvents and, if desired, further additives customary in reactive lacquers, characterised in that the lacquers contain components (A) and (B) in amounts of (A) 60 to 95% by weight of copolymers which contain hydroxyl groups and have been manufactured according to the invention and (B) 5 to 40% by weight of an organic polyisocyanate, the numerical values of (A) and (B) together having to add upto 100% by weight.

16. Stoving lacquers based on copolymers, which are based on vinyl compounds, a-ss-unsaturated monocarboxylic acids and monoglycidyl compounds, the two latter being bonded as esters by an addition reaction, and carry hydroxyl groups, aminoplast resins, organic solvents, and if desired, further additives customary in stoving lacquers, characterised in that the lacquers contain components (A) and (C) in amounts of (A) 70 to 95% by weight of copolymers which contain hydroxyl groups and have been manufactured according to the invention and (C) 5 to 30% by weight of aminoplast resins, the numerical values of (A) and (C) together having to add up to 100% by weight.

17. Process according to Claim 6, characterised in that copolymers are manufactured from a) 20 to 32% by weight of styrene and/or vinyltoluene, b) 16 to 26% by weight of methyl methacrylate, c) 26 to 16% by weight of hydroxyethyl methacrylate, up to 7% by weight of the hydroxyethyl methacrylate optionally being replaced by polypropylene glycol monomethacrylate which has the formula

in which n denotes numbers of 5 to 6, and an average molecular weight of about 350 to 387, d) 6 to 7% by weight of acrylic acid and/or methacrylic acid and e) 23 to 25% by weight of glycidyl esters of aliphatic saturated monocarboxylic acids having 9 to 15 carbon atoms, components d) and e) first being reacted in the presence of at least one of components a) and/or b) and optionally c), to give the addition product, and the components then being copolymerised in the presence of inert solvents, and components a, bc, d and e being so chosen that they make up 100% by weight.

20. Process according to Claim 1, characterised in that copolymers are manufactured from 3 to 40% by weight of a) styrene and/or vinyltoluene and/or b) methyl meth-acrylate, 10 to 40% by weight of b1) acrylates and/or methacrylates of aliphatic saturated monoalcohols having 2 to 12 C atoms, 10 to 30% by weight of c) hydroxyethyl acrylate and/or hydroxyethyl methacrylate or polypropylene glycol monomethacrylate which has the formula

in which n denotes numbers of 5 to 6, and an average molecular weight of about 350 to 387, 5to 12% by weight of d) acrylic acid and/or methacrylic acid and 35 to 15% by weight of e) glycidyl esters of aliphatic saturated monocarboxylic acids having 9 to 15 carbon atoms, components d) and e) first being reacted in the presence of at least one of components a) and/or b) and optionally c), to give the addition product, and the components then being copolymerised in the presence of inert solvents, and components a, b, c, d and e being so chosen that they make up 100% by weight.

21. Process according to Claim 1 or to one of Claims 17 to 20, characterised in that, for copolymers which are intended for crosslinking polyisocyanate, the starting components are so chosen and reacted that copolymers with a hydroxyl group content of about 2 to about 6% by weight, based on the weight of the starting monomers, are obtained.

22. Process according to Claim 21, characterised in that the starting components are so chosen, and reacted for such a time, that copolymers with acid numbers of 2 to 12 and preferably 3 to 6 are obtained.

23. Process according to Claim 20, characterised in that, for copolymers which are intended for crosslinking with aminoplast resins, the starting components are so chosen and reacted that copolymers with a hydroxyl group content of 2 to 4.5% by weight, based on the weight of the starting monomers, and with an acid number of 10 to 50 are obtained.