| 摘要 |
PURPOSE:Hollow yarn useful for a heat exchanger used for controlling blood temperature, having improved adhesiveness to a resin for bonding the end part of the yarn, wherein a great number of very small holes are opened on the outer wall of the yarn and the very small holes are not passed through the inner wall. CONSTITUTION:A blend of a highly crystalline polymer having >=60% crystallinity and 5-50wt% low crystalline polymer having <60% crystallinity is subjected to melt spinning, the prepared undrawn hollow yarn is drawn at >=glass transition temperature - <=the lower melting point of the components -50 deg.C. Consequently, hollow yarn wherein >=20% very small holes with 0.01-50mum based on the area of the outer wall of the hollow yarn are opened on the wall surface and the very small holes are not passed through the inner wall surface, is obtained.
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