GB587309A - Improved process for the production of extensible contractile tubular, annular or the like film products - Google Patents

Abstract

Bottle caps, rings and like tubular film products having a basis of cellulose triesters, such as cellulose triacetate, are formed by a wet-forming process at ordinary temperatures and are impregnated while in the gelatinous state with a mixture of (a) triacetin with (b) a mono-or diester of glycol derived from a lower fatty acid, particularly glycol monoformate, monoacetate or diacetate or with (c) a derivative of glycol or glycerine in which one OH group of the glycol or glycerine molecule is replaced by halogen and which contains a second free OH group or a second OH group replaced by a methoxy or ethoxy radicle. The impregnated film products can be stretched while still moist, but shrink when dried. The impregnation may be effected by dipping the film product into the mixture after coagulation or by incorporating the mixture in both the film-forming solution and the coagulating bath. Synthetic resins, such as polyvinyl esters, polyvinyl formals or esters of polyacids and polyalcohols, may be incorporated in the cellulose ester film-forming solution. In examples: (i) bottle caps of cellulose triacetate formed by a wet-forming process at ordinary temperatures are impregnated while in the gelatinous state with an aqueous triacetin solution containing glycol monochlorhydrin or glycol diacetate, and (ii) film products are obtained from a solution of cellulose triacetate in a mixture of glycol monochlorhydrin, water and triacetin employing a coagulating bath consisting of a more dilute aqueous solution of glycolmonochlorhydrin and triacetin. Specification 477,403 is referred to. The Specification as open to inspection under Sect. 91 refers to a process for the manufacture of bottle caps, rings and like tubular film products having a basis of cellulose derivatives insoluble in water in which the formed articles are impregnated while in the gelatinous state with an ester of glycol or of glycerine in which one OH group of the glycol or glycerine molecule is esterified by either a lower fatty acid or is replaced by a halogen and which contains a second free OH group or a second OH group esterified by a lower fatty acid or replaced by a methoxy or ethoxy radicle. It is stated that the impregnating agent is preferably associated with ordinary plasticising agents of cellulose derivatives. This subject-matter does not appear in the Specification as accepted.