GB603839A - Improvements in the production of crepe and like effects in fabrics - Google Patents

Abstract

Crape and like effects are produced in fabrics which contain in the warp or weft highly twisted, highly shrinkable yarn composed essentially of one or more highly polymerized linear esters which may be obtained by heating one or more glycols of the type HO(CH2)nOH, where n is greater than 1 but not greater than 10, with terephthalic acid or an ester-forming derivative thereof. The filaments of the yarns of these polymers are subjected to drawing so as to produce the high shrinkability, prior to fabric formation. To produce the crape effects, the fabrics are heated while free from tension to a temperature at least 5 DEG C. higher than that at which the filaments of high shrinkability were heated during or after the drawing operation, but lower than the melting point of the polymer. In forming the polymer, ethylene, trimethylene, tetramethylene, hexamethylene, or decamethylene glycol may be heated with terephthalic acid or its aliphatic, cycloaliphatic, or aryl esters, its acid halides, or ammonium or amine salt. The filaments are preferably drawn when heated to a p temperature above 60 DEG C. but at least 30 DEG C. less than the melting point. The yarns may be produced from continuous filaments or from staple fibres. Partially drawn filaments may be twisted and the yarn so formed may be further drawn so as to complete the stretching of the filaments. Single or plied yarns may have their twist set by subjecting them to a temperature at least as high as the temperature of drawing but less than the melting point, while maintaining them under a tension sufficiently low only to prevent retraction in length, or sufficiently low to allow controlled shrinkage. The degree of twist is of the order of 50 to 80 turns per inch. In the case of polyethylene terephthalate yarns which have been drawn at 80 DEG C., the fabrics containing them may be craped by heating at temperatures between 85 DEG and 160 DEG C. The fabrics may be heated with hot water, steam, hot metal surfaces such as hot rollers, any hot inert liquid or gas, or by infra red radiation. The poly ester yarns may be associated with yarns of any other fibrous material such as viscose yarns, in the fabric to be craped. Preferably the highly twisted yarns of the polyesters are woven in pairs, each pair having a twist opposite to the pair of yarns lying next to it in the fabric. This arrangement leads to a more even crimping effect. Specification 603,840 is referred to.ALSO:Crape and like effects are produced in fabrics which contain in the warp or weft, highly twisted, highly shrinkable yarn composed essentially of one or more highly polymerized linear esters which may be obtained by heating one or more glycols of the type HO(CH2)nOH, where n is greater than 1 but not greater than 10, with terephthalic acid or an ester-forming derivative thereof. The filaments of the yarns of these polymers are subjected to drawing so as to produce the high shrinkability, prior to fabric formation. To produce the crape effects, the fabrics are heated while free from tension to a temperature at least 5 DEG C., higher than that at which the filaments of high shrinkability were heated during or after the drawing operation, but lower than the melting point of the polymer. In forming the polymer, ethylene, trimethylene, tetramethylene, hexamethylene, or decamethylene glycol may be heated with terephthalic acid or its aliphatic, cycloaliphatic, or aryl esters, its acid halides, or ammonium or amine salts. The filaments are preferably drawn when heated to a temperature above 60 DEG C. but at least 30 DEG C. less than the melting point. The yarns may be produced from continuous filaments or from staple fibres. Partially drawn filaments may be twisted and the yarn so formed may be further drawn so as to complete the stretching of the filaments. Single or plied yarns may have their twist set by subjecting them to a temperature at least as high as the temperature of drawing but less than the melting point, while maintaining them under a tension sufficiently low only to prevent retraction in length, or sufficiently low to allow controlled shrinkage. The degree of twist is of the order of 50 to 80 turns per inch. In the case of polyethylene terephthalate yarns which have been drawn at 80 DEG C., the fabrics containing them may be craped by heating at temperatures between 85 DEG and 160 DEG C. The fabrics may be heated with hot water, steam, hot metal surfaces such as hot rollers, any hot inert liquid or gas, or by infra red radiation. The poly ester yarns may be associated with yarns of any other fibrous material such as viscose yarns, in the fabric to be craped. Preferably the highly twisted yarns of the polyesters are woven in pairs, each pair having a twist opposite to the pair of yarns lying next to it in the fabric. This arrangement leads to a more even crimping effect. Specification 603,840, [Group IV (a)], is referred to.