| 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 DEG to 22 DEG 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 DEG to 22 DEG C., preferably 17 DEG to 20 DEG 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> |
