GB430409A - Improvements in and relating to cellulose esters of dicarboxylic acid and composition containing these esters - Google Patents

Abstract

Cellulose esters of dicarboxylic acids are made by directly reacting upon cellulose or an esterifiable cellulose derivative such as a cellulose acetate or acetate-propionate with a non-resinous acid dicarboxylic acid ester of a monohydroxy compound or of a non-saccharide polyhydroxy compound. The acid esters employed may be derived from aliphatic, aromatic, saturated, unsaturated or substituted dicarboxylic acids on the one hand, and from mono-, di- or tri-hydroxy compounds on the other; they may be ethyl hydrogen adipate, the corresponding esters of succinic and maleic acids in particular methyl and benzyl acid succinate, and ethylene glycol acid diphthalate. The esterification may be assisted by an impeller such as chlor- or alkoxy fatty acid anhydride, by heating say to 100--125 DEG C., and by the presence of a catalyst such as magnesium perchlorate. The reaction mixture containing a solvent may be spread out in the form of a film, and then brought to reaction subsequently. Similarly moulded articles may be obtained directly by mixing together the cellulose derivative, the acid ester and a plasticizer, and moulding under heat and pressure, the reaction taking place during the moulding operation. Specification 429,915 is referred to. The Specification as open to inspection under Sect. 91 refers to the preparation of non-resinous dicarboxylic acid esters of a non-saccharide polyhydroxy compound by directly reacting on a polyhydroxy compound such as ethylene glycol with an acid monobasic alcohol ester of a dicarboxylic acid, for example, ethyl acid phthalate, the reaction being carried out at a temperature not sufficiently high to cause resin formation. This subject-matter does not appear in the Specification as accepted.