DE2165491C3 - Process for the production of esterification products - Google Patents

Description

30th

There are already processes for the production of hydroxyl polymers by polymerizing «, /? - ung; saturated mono- and dicarboxylic acids or their Esters and vinyl compounds and then Alkenoxylation known. However, by none of the known processes does the copolymerization of Maleic acid, its half or hydroxyl ester as the only carboxylic acid component with vinyl compounds to a non-gelled hydroxyl polymer with sufficient degrees of polymerization and more suitable Color number.

All three possible process sequences lead to unusable resins according to the known processes or are extremely difficult to carry out in terms of process technology and are therefore uneconomical:

Way 1: anhydride copolymerization - esterification - Alkenoxylation

Way 2: half esterification - half ester copolymerization - Alkenoxylation

Way 3: half esterification - alkenoxylation -
Copolymerization

45

50

Wegl

The copolymerization of maleic anhydride and vinyl aromatics, especially styrene, has been around for a long time known and is an example of a strictly alternating sequence of monomers in the copolymer. It is also known that the length of the molecular chains (the K value is determined as a measure of this) strongly depends on the so Temperature depends, for the production of the desired coating resins, the K value of the product may be Do not exceed a certain height, otherwise both the end product, the paint resin solution, will be at the required level Solids concentration has too high a toughness, as well as a quantitative esterification of the Anhydride groups is no longer guaranteed. The copolymerization can take place in aromatic solvents although still at 125 "C, due to the addition of saturated Hydrocarbons even at 135 "C, as precipitation polymerization be carried out without the precipitating polymer particles sticking to one another. at Temperatures around 150 "C, one to achieve the desired K value, preferred temperature range, one obtains lubrication that is not technically possible are more to be processed.

Way 2

Basically there are no difficulties in producing maleic acid half-esters from maleic anhydride with alcohols, although one must work under precisely defined conditions so that the residual anhydride content remains very low and, on the other hand, no diesters are formed. Under polymerization conditions, however , the maleic acid half-esters tend to disproportionate a maleic acid-I-maleic acid diester. Maleic acid diesters are, however, practically polymerization inactive under the conditions of the main reaction, copolymerization of maleic acid half-esters and styrene. This not only results in a loss of monomers, but the residual monomer content also interferes with the reaction with alkene oxides and later in the paint resin.

Way 3

The conversion of maleic acid half-esters with 1,2-epoxides is possible, but it also occurs higher molecular weight products that tend to become resinous. One side reaction is the reaction of hydroxyl groups from either hydrolyzed epoxide or the hydroxyl monomers with the double bond maleic acid or its derivatives. This is how "paint and varnish" work. 75: 523 (1969), the reaction of Glycol with the double bond of maleic acid derivatives of various types is described.

The patent 21 37 239 shows that the difficulties outlined by a modification of path 1 be overcome by allowing the copolymerization with maleic anhydride in the presence of a certain Dispersant and a high-boiling aromatic hydrocarbon. without smearing occurring, at temperatures around 150 ° C and above technically simple and a A suitable K value can be set for the use of the end products. The K value is between 16 and 22, preferably between 18 and 20. The esterification also changes the color quality of the resin solution practically not affected.

It has now been found, surprisingly, that when the high-boiling aromatic Hydrocarbon through a high-boiling hydrocarbon cut with low aromatic and Olefin content, e.g. B. a kerosene cut, which at Normal pressure between 170 and 230 "C boils, not only the copolymerization of styrene maleic anhydride, but also the two subsequent process stages - Half-esterification and alkenoxylation - can be carried out in dispersion. Another advantage consists in the fact that in the Halbveresteryng and Alkenoxylation forming solid particles are obtained as microbeads and are separated from the Allow the bulk of the liquid phase to be easily separated off by filtration. Residues of high-boiling hydrocarbons can be removed by washing with low-boiling hydrocarbons, so that the Varnish resin component without a large amount of drying time

wall can be obtained as solid resin.

According to the invention, the process according to patent 21 37 239 is used for the production of esterification products by copolymerization of vinyl aromatic hydrocarbons with 8-12 carbon atoms with maleic anhydride in an aromatic hydrocarbon and subsequent partial esterification with monohydric alcohols and alkenoxylation of the copolymer, in which the copolymerization at temperatures of 120-175 ° C in the presence of a dispersant is carried out by a copolymerization of (a) isobutylene or styrene with (b) half-esters from maleic acid and a mixture of long-chain aliphatic alcohols with 12-18 carbon atoms has been modified to the effect that is Copolymerization, half-esterification and alkenoxylation in a high-boiling hydrocarbon cut be carried out with low aromatic and olefin contents.

It was surprising that, according to the process according to the invention, the state of suspension can be maintained over all three process steps, since the polarity of the liquid phase increases in the second stage due to the addition of the alcohol required for esterification, the alcohol being used to achieve a sufficient degree of esterification must be added in a small excess, while the solubility of the copolymer in non-polar liquids increases sharply from the first to the third stage. On the other hand, the dispersant should be adapted to the polarity difference between the disperse and the continuous P..ase. The utility of the present invention ^used% sn Dispergiermitteltypen also for the third Sfife is obviously given by the fact that in the Alkenoxylierung -es Halbesterpolymeren a partially Alkenoxylierung of the dispersant occurs contrast, can not be used in the first or second stage of a previously ilkenoxyliertes dispersant since it react with esterification with the anhydride groups of the polymer and lead to complete crosslinking (gel formation).

The additional advantage of the method according to the invention is that in a range from 140 to 175 ° C can be copolymerized, according to known Procedure is technically not possible.

The subsequent partial esterification (half-esterification is sought) is carried out by adding monohydric, preferably aliphatic alcohols with 3-12 C atoms, especially of aliphatic monoethers such as glycols, with the addition of acidic catalysts, preferably phosphoric acid or its acidic esters and preferably in the temperature range of 150-175 ° C. Of the vinyl aromatic hydrocarbons with 8-12 and especially 8 to 10 carbon atoms as copolymerization partners of maleic anhydride are, in addition to styrene, the kernalkyüerten styrenes, such as the vinyl toluenes and vinyl xylenes are suitable. Styrene is preferably used.

The reaction medium used is high-boiling hydrocarbon cuts with low aromatic and olefin contents, in particular technical mixtures of these hydrocarbons, such as those found in kerosene, for example, the kerosene fraction having a boiling range of 170 ° C-280 ° C, preferably 170 ° C-230 ° C, at normal pressure, as well as an aromatic ^{content of approx. 15 vol- 1} Vb and an olefin content of approx. 2 vol .-%. The aromatics and olefins are in the same boiling range as the aliphatic hydrocarbons. The higher-boiling hydrocarbons are preferred because the reaction temperatures can be carried out at normal pressure. In principle, however, the reaction can also be carried out at excess pressure.

The aromatic content of the hydrocarbon cuts can be up to z »? 0% by volume, that of olefins up to 3% by volume.

The dispersant is composed of a copolymerization of (a) isobutylene or styrene with (b) half-esters Maleic acid and a mixture of long-chain, aliphatic alcohols with 12-18 carbon atoms been received.

example 1

420 g kerosene, which contains 20 vol% aromatics and 3 Vol-% contained olefins and the 2 g of a copolymer of isobutene and the maleic acid half ester of n-Alkanols with 12-18 carbon atoms are added was heated to 165 ° C. In the course of 1 hour, 104 g of styrene and 98 g of maleic anhydride were added to this solution and 4 g of benzoyl peroxide (as a 40% suspension) metered in evenly, the temperature increasing The beginning rose by approx. 5 ° C. After a further hour of post-reaction at the reaction temperature, the Temperature increased to 175 ° C and it wuide inside a mixture of 118 g of 2-butoxyethanol for 1 hour (Butyl glycol) and 0.8 g of 89% phosphoric acid evenly metered in. The reaction mixture, in which the copolymer was still present in disperse form, was allowed to React for a further 2 hours at 175 ° C., then gave 183 g of n-butanol for post-esterification with cooling 120 ° C and held for 1 hour at this temperature. A mixture of was then cooled to 90 ° C 10 g of dimethylformamide and 10 g of water were added and 116 g of propylene oxide were added over the course of 1 hour and leave to react for 8 hours at 95 ° C. The reaction mixture now consisted of finely divided Microbeads and liquid phase. The solid was separated from the liquid phase by filtration and washed with petroleum ether. After drying, a solid resin with an acid number of 43 and was obtained a melting range of 100-115 ° C.

Example 2

840 g of kerosene (composition see Example 1), to which 8 g of a copolymer of isobutene and the maleic acid half-ester of n-alkanols with 12-18 carbon atoms had been added, was ^{heated to 165 °} C. In this solution, 208 g of styrene were added over the course of 1 hour , 196 g of maleic anhydride and 8 g of benzoyl peroxide (as a 40% suspension) were evenly metered in, the temperature rising by about 5 ° C. at the beginning. After a further hour of post-reaction time at 170 ° C., the temperature was increased to 175 ° C. a mixture of 236 g of butyl glycol and 1.6 g of 89% phosphoric acid was metered in uniformly over a period of 1 hour. The reaction mixture, in which the copolymer was still present in disperse form, was allowed to react for a further 2 hours at 175.degree. C., 37 g of n-butanol were then added to the postesterification with cooling to 120.degree. C. and kept at this temperature for 1 hour cooled to 80 ° C., a mixture of 20 g of dimethylformamide and 20 g of water was added and 176 g of ethylene oxide were added over the course of 1 hour and allowed to react for 6 hours at 75 °. The solid was separated off as in Example 1

carried out The solid resin had an acid number of 3 and a melting range of HO-125 "C,

The solid resin to be obtained in this way can - if appropriate after pigmentation in the melt and additives suitable hardener - used for electrostatic powder coating.

Claims (2)

Patent claims: 1. Modification of the process according to the patent 21 37 239 for the preparation of esterification products by copolymerization of vinyl aromatic Hydrocarbons with 8-12 carbon atoms with maleic anhydride in an aromatic Hydrocarbon and subsequent partial esterification with monohydric alcohols and alkenoxylation of the copolymer in which the copolymerization carried out at temperatures of 120-175 "C in the presence of a dispersant which is produced by a copolymerization of (a) isobutylene or styrene with (b) half-esters from is Maleic acid and a mixture of long-chain aliphatic alcohols containing 12-18 carbon atoms has been obtained, characterized in that copolymerization, half-esterification and alkenoxylation in a high-boiling hydrocarbon cut with low aromatic and Oiefingehaiten are carried out. 2. The method according to claim 1, characterized in that that with a kerosene fraction that boils at normal pressure between 170 and 230 ° C, is being worked on.