| 摘要 |
<p>Artificial filaments, films, or similar articles, having a basis of a linear polymerized ester (obtained by heating one or more glycols of the series HO(CH2)nOH, where n is an integer greater than 1 but not greater than 10, with terephthalic acid or an ester-forming derivative thereof) are heated to a temperature which is below and preferably at least 30 DEG C. below the melting point, and subjected to a tension sufficient to cause permanent elongation. The glycol used in making the polymer may be ethylene, tri-methylene, tetramethylene, hexamethylene, or decamethylene glycol, and it may be condensed with terephthalic acid or an aliphatic, cycloaliphatic, or aryl ester, or acid halide, or ammonium or amine salt thereof. Continuous filaments or yarns may be obtained from the polymer by melt spinning, or from solutions of the polymer in solvents such as cresols, nitrobenzene, and tetrachloroethane. Films may be obtained by extrusion of the molten polymer and quenching the extruded polymer by jets of cold air or other inert gas, or by immersion in a cold liquid such as water, or by contact with a cooled metal surface. The polymer may be extruded as a large diameter but thin walled tube which may be flattened on cutting so as to provide one or more films. The films are preferably stretched after extrusion while they are being quenched. Films may also be obtained by casting a solution of the polymer and evaporating the solvent. The drawing to effect molecular orientation is preferably carried out as soon as possible after the formation of the filaments and films. Fine filaments are preferably drawn at a temperature greater than 60 DEG C. but thicker filaments suited for use as bristles are preferably drawn initially at a temperature of 40 DEG C. or less. Drawing may be effected in two or more stages. The drawing is preferably followed by a heat setting treatment which is at least as high as the maximum drawing temperature. This treatment may comprise the initial stage of cooling filaments which have been drawn, or may be a separate treatment. Heat setting may be effected under a tension which allows relaxation, e.g. 10-15 per cent. Twisted yarns such as high twist yarns suited for the production of crape fabrics, or sewing threads may be subjected to heat setting. Films may be stretched longitudinally and transversely. Specifications 533,307, 536,379, 536,380, 542,509, 567,358, 578,079, 588,411, 590,451, 603,839, 603,842 and 603,843 are referred to.</p> |
