| 摘要 |
<p>Polypivalolactone yarn has a strength of at least 5g/denier, and an elongation of at most 70%, pref. 20%. The yarn is produced by (a) drawing polypivalolactone yarn at a temp. between 20 deg. and 220 deg.C to give a yarn with an elongation of 10-100%, (b) subjecting the yarn to thermal relaxation at 110-220 deg.C without drawing, and (c) drawing the yarn at a temp. between 100 deg. and 220 deg.C, to give a yarn with an elongation of 5-70%, pref. 5-20%. The temp. in stage (a) is pref. at least 125 deg.C. The yarns have a combination of properties which makes them very suitable for use in applications such as reinforcement of elastomers, esp. tyres, and in cables, such as ships' cables.</p> |
