GB599669A - Improvements in or relating to the production of artificial filaments, foils and like shaped articles - Google Patents

Abstract

Artificial filaments, threads, yarns, films, foils and like shaped articles are obtained by shaping a solution of a fibre- or film-forming polyamide in a phenolic solvent and setting it in an organic liquid medium which comprises a substantial proportion of a ketone of the formula R1.CO.R2, where R1 is the methyl radical or a substitution derivative thereof, and R2 is the methyl or ethyl radical or a substitution derivative thereof. The polyamide may be obtained from a diamine and a dicarboxylic acid, or from an aminocarboxylic acid by selfcondensation. The polymer may have a molecular weight of 4000-10,000 or more. The phenolic solvent may be phenol, a xylenol, a cresol, a - or b -naphthol, resorcinol, a halogenated phenol, e.g. o- and p-chlorphenol, 2 : 4-dichlorphenol and 3-hydroxy-6-chlortoluene, an amino phenol, salicylic acid, o-hydroxy benzyl alcohol, or an oxy-di-phenyl. The solution is in a fluid or highly plastic state while it is being shaped and if necessary it is heated. The solution may be formed directly in the process of producing the polymer. The ketone used for the setting operation may be acetone, methyl ethyl ketone, chloracetone, acetol, acetol methyl ether, or acetol acetate. Other non-solvents may be present in the setting medium, e.g. acetophenone, methyl alcohol, ethyl acetate, diethyl ether, petroleum ether, or toluene. A small proportion of water may be present. Solvents or swelling agents may be incorporated in the setting medium, e.g. formic, acetic, lactic, stearic, succinic, adipic or citric acid, or methyl formamide, acetamide, adipamide or p-toluene sulphonamide. The shaping may be effected at 200 DEG C. or more, but the setting medium is preferably maintained at a p lower temperature, e.g. 15-30 DEG C. The spinning orifices are preferably arranged just above the setting medium in an atmosphere of inert gas such as nitrogen, hydrogen or carbon dioxide. The filaments may be submitted to stretching during production. They may be passed through one or more washing baths, e.g. of low boiling petroleum hydrocarbons or dried by passage through a hot gaseous medium before being wound up. The filaments may be twisted or doubled to produce yarns, or they may be united by means of softening agents, heat or pressure to form bristles, straws and the like. Bristles or straws may be obtained directly by extrusion. Sheet materials may be used for wrapping purposes or as intermediate layers in safety glass manufacture. In an example, a fibre-forming polyamide is prepared by refluxing hexamethylene diamine with adipic acid in xylenol, oxygen being excluded. The resulting polymer is fed through narrow heated tubes and through spinning orifices situated just above a bath containing acetone. The orifices are heated electrically. Specifications 529,510, 540,967 and 599,668 are referred to.