| 摘要 |
<p>Polyethylene terephthalate yarn is prepared by spinning under very high-stress conditions wherein oriented-crystalline undrawn yarns are obtained. Selection of process parameters yields a partially oriented semicrystalline undrawn yarn with a crystallinity of 16 to 24 percent and a melting point elevation of 14 to 22°C which is drawn to produce the resulting unique combination of properties: (A) a terminal modulus of at least 20 g/d, (B) a dimensional stability defined by E4.5 +FS < 11.5 percent, (C) a tenacity of at least 5 grams per denier, (D) a melting point elevation of 14 to 22°C, preferably 17 to 20°C, and (E) an amorphous orientation function of less than 0.75. The resulting treated tire cord unexpectedly provides high ultimate elongation and high toughness in combination with improved dimensional stability.</p> |
