GB922406A - Improved fibres and filaments and fabrics made therefrom - Google Patents

Abstract

Crimped drawn tow of synthetic polymer, e.g. polyester and copolyester, polyamide or polypropylene, filaments, before any stapling or conversion to top by cutting or stretchbreaking and heat-setting of the continuous filaments or stapled fibres to reduce residual shrinkage (in boiling water for one minute) to less than 1% and for setting the imparted crimp, is treated by uniform application of a chemical agent under such conditions that the filaments are weakened, i.e. tenacity is reduced by at least one third, at intervals corresponding to the apexes of their crimp. Lubricants and/or antistatic agents may be applied before or after heat-setting. The permanent deformations, occurring with a frequency of 5-18 crimps per inch, are such as to produce compression beyond the elastic limit on the inner curvature of the bent filament and a tension on the outer curvature not beyond 5% of the elastic limit, and these localized stress conditions concentrate the selective weakening action of the chemical agent at the apexes of the crimps, the portions of the filament there-between remaining substantially unaffected. Fabrics knitted or woven from yarns of the continuous or stapled filaments are resistant to "pilling" because loosely held fibres which migrate to the surface are broken at the weakened intervals under mechanical stress encountered during wear, and may be removed as by brushing. The chemical agent may be an alkaline solution such as sodium hydroxide solution, ammonia, solutions of a quaternary ammonium salt, e.g. cetyl trimethyl ammonium bromide and lauryl dimethyl benzyl ammonium chloride, or methyl alcohol, which may be added to the sodium hydroxide solution, diamines such as a solution of hexamethylene diamine, anhydrous glycols including high molecular weight glycols their esters and ethers such as polyethylene glycols and nonyl phenyl polyethylene glycol ethers which are still liquid at room temperature. Inert diluents and/or accelerators may be added. Melt-spun, drawn or undrawn filaments of polyethylene terephthalate, prior or subsequent to the crimping and weakening treatment, may be treated by spraying or immersion with hot substantially anhydrous polyethylene glycols or nonyl phenyl polyethylene glycol ethers of molecular weight of 200-2,000 at a temperature above 80 DEG C. but at least 30 DEG C. below the melting temperature of polyethylene terephthalate, in order to improve the dye uptake. The filaments may be of circular or non-circular, e.g. cruciform, y-shaped, trilobal, dog-bone, cross-section. Specifications 917,497 and 919,860 are referred to.ALSO:Crimped drawn tow of synthetic polymer, e.g. polyester and capolyester, polyamide or polypropylene, filaments (see Groups IV(a) and IX) is treated by uniform application of a chemical agent under such conditions that the filaments are weakened, i.e. tenacity is reduced by at least one third, at intervals corresponding to the apexes of their crimp. Lubricants and/or antistatic agents may be applied before or after heat-setting. The permanent deformations, occurring with a frequency of 5-18 crimps per inch, are such as to produce compression beyond the elastic limit on the inner curvature of the bent filament and a tension on the outer curvature not beyond 5% of the elastic limit, and these localized stress conditions concentrate the selective weakening action of the agent at the apexes of the crimps, the portions of the filament therebetween remaining substantially unaffected. Fabrics knitted or woven from yarns of the continuous or staple filaments are resistant to "pilling" because loosely held fibres which migrate to the surface are broken at the weakened intervals under mechanical stress encountered during wear, and may be removed as by brushing. The agent may be an alkaline solution such as sodium hydroxide solution, ammonia, solutions of a quaternary ammonium salt, e.g. cetyl trimethyl ammonium bromide and lauryl dimethyl benzyl ammonium chloride, or methyl alcohol, which may be added to the sodium hydroxide solution, diamines such as a solution of hexamethylene diamine, anhydrous glycols including high molecular weight glycols their esters and ethers such as polyethylene glycols and nonyl phenyl polyethylene glycol ethers which are still liquid at room temperature. Inert diluents and/or accelerators may be added. Melt-spun, drawn or undrawn filaments of polyethylene terephthalate, prior or subsequent to the crimping and weakening treatment, may be treated by spraying or immersion with hot substantially anhydrous polyethylene glycols or nonyl phenyl polyethylene glycol ethers of molecular weight of 200-2000 at a temperature above 80 DEG C. but at least 30 DEG C. below the melting temperature of polyethylene terephthalate, in order to improve the dye uptake. The filaments may be of circular or non-circular, e.g. cruciform, Y-shaped, trilobal, dog-bone, crosssection. Specifications 917,497 and 919,860 are referred to.