Patent GB-544613-A (GB)
Title: Manufacture of synthetic resins
IPC: C08F8/28
Filed: 1940-05-20
Abstract: 544,613. Polyvinyl ketals. DU PONT DE NEMOURS & CO., E. I. May 20, 1940, No. 8928. Convention date, May 20, 1939. [Class 2 (iii)] Polyvinyl ketals are prepared by reacting, under substantially anhydrous conditions and in the presence of a condensation catalyst of acid reaction, polyvinyl alcohol or a partially hydrolyzed polyvinyl ester with a monomeric ketal of a ketone having the formula R-CO-R<SP>1</SP> in which R and R<SP>1</SP> are similar or dissimilar aliphatic or aromatic radicles, or (in the presence of an aliphatic alcohol containing less than four carbon atoms) with the unsaturated ether corresponding with such a ketal, or with other substances capable of generating a ketal in situ. The process may be effected in the presence of methyl or ethyl alcohol, acetic acid, ethyl acetone, methyl ethyl ketone, chloroform, or excess monomeric ketal, and may be carried out under pressure. Specified monomeric ketals are the dimethyl and' diethyl ketals of acetone, methyl ethyl ketone, methyl propyl ketones, acetophenone, methyl n-amyl ketone and ketals from diethyl ketone, propiophenone ethyl propyl ketones, di-propyl ketones, benzophenone, mesityl oxide, methyl vinyl ketone and methyl cyclohexyl ketone ; cyclic ketals derived from polyhydric alcohols such as ethylene glycol and pentaerythritol, and ketalacetals may also be employed. The monomeric ketal may be prepared in situ, e.g. by the reaction of a ketone with orthoformic esters, imino ethers, alkyl orthosilicates or dialkyl sulphites, the reaction of an unsaturated ether and an alcohol, or alcohol interchange with mercaptoles. The polyvinyl alcohol may be prepared by the hydrolysis of any polyvinyl ester, e.g. polyvinyl acetate or propionate, or mixed polyvinyl esters, e.g. tne acetate-stearate. In examples, polyvinyl ketals are prepared from polyvinyl alcohol and 2 : 2-dimethoxybutane, 2 : 2-diethoxybutane, 2 : 2-diethoxypropane, 2 : 2-diethoxypentane, the diethyl ketal of acetophenone, 2-methyl-2-ethyl dioxolane, 2-methoxybutene-1 and ethanol, ethylorthoformate and acetone, 2 : 2-diethoxybutane and 2 : 2-diethoxypropane, 2 : 2-diethoxybutane and 1 : 1-diethoxybutane, benzaldehyde and 2 : 2- diethoxybutane, and methyl acrolein and 2 : 2- diethoxybutane. The reaction product is treated with alkali to partially or completely neutralize the catalyst and the resin precipitated by water. The resin may be mixed with other resins, waxes, driers, fillers, pigments, dyes and with plasticizers, e.g. esters of phthalic or aliphatic dibasic acids ; esters of ethylene glycol, glycerol or di- and polyethylene glycols polyphenyl methanes ; toluene sulphonamides ; diphenyl ethers ; alkyl and aryl phosphates ; esters of aliphatic hydroxy acids and their ethers ; esters and ethers of xylylene glycols ; chloronaphthalenes ; and glycerol acetal esters and ethers. The resins may be used in lacquers, paints or varnishes, in coating, impregnating, sizing or adhesive compositions, and in the preparation of insulators, safety glass, gramophone records, buttons, combs, dishes and screw caps, and may be formed into threads, bands, tubes, films or sheets.