| 摘要 |
Filamentary material made from an oxymethylene polymer is subjected to a temperature between 45 and 5 DEG C. below the crystalline melting-point of the polymer for a time sufficient to increase the crystallite size of the polymer while maintaining the material under sufficient tension, if necessary, to prevent surface fusion thereof. The material may be filaments, yarns or knitted or woven fabrics of oxymethylene polymer, or copolymer comprising oxymethylene and oxyethylene groups. The process, while imparting strength and creep resistance to filaments (Division B4-B5) may be used to set yarn or fabric in a predetermined shape. Yarn may be bulked, voluminised or textured by being held in a crimped, curled or looped configuration, as by knitting, twisting, or use of meshed gears or stuffing box, while heat is applied. An increase on crystallite size of at least 15% may be achieved by heating the material for e.g. 0.5-15 minutes at 150-160 DEG C. Heating may be effected by e.g. steam or air. In Example 1, a yarn melt-spun from a copolymer of trioxane and ethylene oxide is, drawn, twisted, heated on the bobbin at constant length for 15 minutes at 160 DEG C. and the twist is then removed by back twisting, resulting in a bulked yarn. In Example 4, ladies stockings, knitted from the same co-polymer are pre-boarded at 115 DEG C. for 1 minute, dyed, and post-boarded at 160 DEG C. for 5 minutes.
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