DE1265414B - Process for making polyesters - Google Patents

Description

Process for making polyesters It is known to use dicarboxylic anhydrides with epoxies, e.g. B. ethylene and propylene oxide, in the presence of catalysts and possibly of compounds with mobile hydrogen atoms, namely hydroxyl and / or carboxyl compounds, as starter compounds to convert to polyesters.

According to the invention, valuable novel polyesters are obtained by reacting dicarboxylic anhydrides with glycidyl ethers of monohydric phenols which have a hydrocarbon radical bonded to the aromatic nucleus, optionally in a mixture with other monoepoxides, in the presence of catalysts and optionally in a mixture with compounds with mobile hydrogen atoms, if p -Vinylphenylglycidyl ether of the general formula in which R1, R.3 and R3 denote hydrogen atoms or aliphatic, cycloaliphatic or aromatic radicals, are used.

As p-vinylphenylglycidyl ether, for example, can be used: the glycidyl ethers of p-vinylphenol, p - (1 - methylvinyl) - phenol, (p - isopropenylphenol), p - (1,2 - dimethylvinyl) phenol, (p - isobutenyl phenol), p - (2 - methyl vinyl - phenol) p - (1 - ethyl vinyl) - phenol, p - (2 - ethyl vinyl) - phenol, p - (1 - Methyl - 2 - ethylvinyl) - phenol, p - (1 - propylvinyl) - phenol, p - (2 - isopropylvinyl) - phenol, p - (2,2 - dimethylvinyl) - phenol, p - (1 - methyl-2-butylvinyl) - phenol, p- (1-cyclohexylvinyl) -phenol and p- (1-phenylvinyl) -phenol.

The p-vinylphenylglycidyl ethers used according to the invention can are produced e.g. B. by converting the corresponding p-vinylphenols with Epihalohydrins in the presence of catalytic amounts of tertiary amines into the corresponding Halohydrin ether and splitting off of hydrogen halide therefrom with alkali or by Reaction of the corresponding p-vinylphenols with epihalohydrins or dihalohydrins in the presence of aqueous alkalis.

In addition to the p-vinylphenyl glycidyl ethers, other monoepoxides, such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, methyl glycidyl ether, Ethyl glycidyl ether, allyl glycidyl ether and styrene oxide can also be used.

As dicarboxylic acid anhydrides, mainly the anhydrides are more aromatic, cycloaliphatic or saturated aliphatic dicarboxylic acids are suitable. Called are for example the anhydrides of the following dicarboxylic acids: succinic acid, glutaric acid, Hexahydrophthalic acid, endomethylene tetrahydrophthalic acid, hexachloroendomethylene tetrahydrophthalic acid, phthalic acid, Naphthalic acid, naphthalene-2,3-dicarboxylic acid, tetrachlorophthalic acid.

In addition, aliphatically unsaturated dicarboxylic anhydrides, such as maleic anhydride, dichloromaleic anhydride or citraconic anhydride, be used. However, the content of aliphatically unsaturated dicarboxylic acid anhydrides should generally less than about 50 mole percent based on the sum of those used Anhydrides, because the greater the content of such in the reaction mixture unsaturated acid anhydrides the risk of discoloration of the products increases.

The applicable molar ratio between dicarboxylic anhydrides and Epoxies is 1: 1.

Organic or inorganic bases or can be used as catalysts their salts in question. These include B. tertiary amines, tertiary phosphines, quaternary Ammonium or phosphonium hydroxides or their salts as well as correspondingly structured Anion exchange resins also metal hydroxides, metal salts and basic acting Metal oxides. Of the types of compounds mentioned, the metal salts are the most suitable, because their use leads to very light-colored products. The use of neutral salts strong or moderately strong inorganic bases also has the advantage that they a reaction of dicarboxylic anhydrides and monoepoxides in a molar ratio of 1: 1 enables.

The solubility of the catalysts is a prerequisite for the effectiveness of the catalysts in the reaction mixture.

Preferred catalysts which may be mentioned are, for example: the Lithium, sodium, magnesium or cadmium salts of hydrogen chloride, hydrogen bromide, Trichloroacetic acid, alkyl sulfonic acids or phosphoric acid dialkyl esters. The catalysts can generally be used in amounts of from 0.01 to 30%.

As is known per se, the additional use is advantageous of compounds with mobile hydrogen atoms, preferably mono- or / and polyvalent Alcohols or carboxylic acids.

These compounds act as starter molecules for the implementation resulting polyester chains and allow the use of lower reaction temperatures and shorter reaction times as well as a defined structure of the polyester molecules.

Are temperatures used in the implementation at which none Reaction between carboxyl and hydroxyl groups takes place - these are usually Temperatures below about 140 "C, the number of moles of polyester molecules formed equal to the number of moles of starter compounds used.

With trifunctional or higher functional alcohols or carboxylic acids arise branched polyesters, while with monoalcohols or monocarboxylic acids as starter compounds linear polyesters with monoset indifferent end groups are formed.

The molar amount of compounds with mobile hydrogen atoms should be smaller than the number of moles of dicarboxylic acid anhydrides or epoxy compounds.

The process of the invention can be carried out at temperatures between 80 and 180 "C. In the presence of compounds with mobile hydrogen atoms Temperatures below 150 ° C. are generally preferred as starter molecules. If higher temperatures are used in order to achieve sufficiently short reaction times, so it can be advantageous to use polymerization inhibitors, such as Hydroquinone, 3,6-dipropylpyrocatechol or 2,6-di-tert-butyl-p-cresol, in lower amounts Amount, e.g. B. from 0.005 to 0.1 O / o to be added.

It is advisable, with the exclusion of oxygen in an inert atmosphere, z. B. nitrogen or carbon dioxide atmosphere to work.

The reaction components can under normal pressure or increased pressure be implemented with each other in different ways, for example by the fact that a mixture of all components is heated to the desired temperature and the occurring heat of reaction dissipates by cooling or by the epoxides at the Reaction temperature in the mixture of dicarboxylic anhydrides, catalyst and optionally enters starter compounds in accordance with the rate of conversion. Especially when you use different dicarboxylic anhydrides and one If you want to achieve a defined polyester structure, it is advantageous to also use the anhydrides to be added in portions to the reaction mixture.

The method of the invention is characterized in that it the Production of valuable unsaturated polyesters with, if desired, extremely low Acid numbers and with any but defined arrangement of the monomer units at low temperatures and within short reaction times enables. Another The advantage is that the implementation can be carried out with simple means can, because no condensation products have to be separated off during the reaction, so that the process can easily be operated in a continuous manner.

The process products or mixtures thereof which can be prepared according to the invention with monomeric vinyl and / or allyl compounds can lead to insoluble masses with very good properties.

It is known from US Pat. No. 2,966,479 using certain catalysts by reacting dicarboxylic acid anhydrides with glycidyl esters or ethers of unsaturated aliphatic alcohols or carboxylic acids of high molecular weight Manufacture polyesters with molecular weights above 8000.

However, this gives products which because of their low reactivity of the ethylenic double bonds with monomeric vinyl compounds such as styrene the otherwise usual temperatures cannot be copolymerized, or, for example when using maleic anhydride as the dicarboxylic acid anhydride, strongly discolored products are obtained which cannot be used further without further ado can.

Also the glycidyl ethers mentioned in British Patent 824 302 monohydric phenols, which on the aromatic nucleus are the residues of higher unsaturated Contain hydrocarbons with 10 to 28 carbon atoms and the rest there Used to make epoxy resins are at normal temperatures Cannot be copolymerized with monomeric vinyl compounds.

In contrast, according to the invention, surprisingly, largely colorless unsaturated polyesters with possibly an extremely low acid number obtained, which with monomeric vinyl and / or allyl compounds in the usual way to moldings with excellent properties, in particular with excellent mechanical strength and very good water and chemical resistance, cured can be.

Example 1 In one with stirrer, internal thermometer, nitrogen supply line and attached heatable dropping funnel provided reaction flask, which by means of after a mercury immersion has been completed against the external atmosphere Generation of a nitrogen atmosphere 40.3 g of 2-phenoxyethanol and 237 g of phthalic anhydride melted and heated to 125 "C.

At this temperature, 1.4 g of lithium chloride and then within 3 hours at a constant dropping rate 283 g of liquefied p-isopropenylphenyl glycidyl ether (melting point 44 to 45 "C). The Mixture is then heated for a further 2 hours at 125 to 1300C and 1 hour at 145 "C, to convert the last parts of the glycid ether. After that there is an almost colorless one Resin with an acid number of 14 and a softening point of 700 C (according to the method von K rä m e r -Sarnow).

Example 2 In a mixture of 37.4 g of 2-ethylhexanol, 88.8 g of phthalic anhydride, 20.0g succinic anhydride and 1.22g magnesium chloride, which are found in one Reaction vessel, as described in Example 1, is at 125 to 1300C within 60 minutes 153 g of p-isopropenylphenyl glycidyl ether with uniform Speed dripped in. The reaction is allowed to continue for 1 hour at the same temperature, then adds another 88.8 g of phthalic anhydride and 20.0 g of succinic anhydride all at once and carries another 153 g of p-isopropenylphenyl glycidyl ether in the course of 80 minutes.

The mixture is 2 hours at 125 to 130 "C and then at 140 "C, until the acid number of the product no longer changes. The The final value of the acid number is about 6, the softening point is 68 ° C.

Example 3 42.4 g sebacic acid, 186.5 g phthalic anhydride, 283 g of p-isobutenylphenyl glycidyl ether (melting point 540 ° C.) and 2.87 g of the cadmium salt of the phosphoric acid diethyl ester are in an apparatus equipped with a reflux condenser under a nitrogen atmosphere Stirred for 1 hour at 110 "C and 2 hours at 125 or 135" C. Then drips one at 125 "C within 30 minutes 43 g of liquid propylene oxide to the mixture and allowed to react for a further 30 minutes at the same temperature. Last will Excess propylene oxide by connecting the reaction vessel to a water pump deducted. The resulting curable polyester has an acid number of 1 to 2.

Example 4 207 g of 2-phenoxyethanol, 444 g of phthalic anhydride and 10 g of lithium chloride were heated to 130 ° C. under nitrogen. Within 30 minutes, one third of one of 1422 g of p-isopropenylphenyl glycidyl ether is worn and 78 g of butylene oxide existing mixture in the reaction mixture and leaves React for another hour at unchanged temperature. Then 462 g Add hexahydrophthalic acid to the reaction vessel.

Then another third of the epoxy mixture is applied to the one described Way to implement.

Finally, a further 444 g of phthalic anhydride are added and the mixture is set with the last third of the mixture of the epoxy compounds. Finally the reaction mixture is heated to 140 ° C. for a further 2 hours. A polyester is obtained from the acid number 16, with the hexahydrophthalic anhydride groups in the middle the polyester molecules are arranged.

Example 5 In a reaction flask fitted with a reflux condenser are 32.2 g of 2-ethylhexanol-1, 123.5 g of hexahydrophthalic anhydride under nitrogen, 80 g of succinic anhydride and 371 g of p- (n-phenyl) vinylphenyl glycidyl ether vom Melting point 58 to 59 "C together with 1.45 g of lithium chloride for 1 hour each 110, 120 and 1300C stirred and then heated to 140 "C for two more hours.

45 g of propylene oxide are then added dropwise at 125 ° C. in the course of 30 minutes into the reaction mixture and leaves at the same temperature with stirring for about React for 1/2 hour. The unreacted propylene oxide is then in a vacuum distilled off. A curable polyester remains as the reaction product Acid number is about 2 and copolymerized with monomeric vinyl compounds can be.

Claims (1)

Claim: Process for producing polyesters by reacting dicarboxylic acid anhydrides with glycidyl ethers of monohydric phenols which have a hydrocarbon radical bonded to the aromatic nucleus, optionally in a mixture with other monoepoxides, in the presence of catalysts and optionally in a mixture with compounds with mobile hydrogen atoms, characterized in that one p-Vinylphenylglycidyläther of the general formula in which R1, R2 and R2 are hydrogen atoms or aliphatic, cycloaliphatic or aromatic radicals, are used. Documents considered: British Patent No. 824 302; U.S. Patent No. 2,966,479.