| 摘要 |
PROBLEM TO BE SOLVED: To improve orientation formability and to facilitate molding of an oriented sheet of a high orientation ratio by using anα-olefin (co)polymer becoming a specific weight-average molecular weight and a melted state or a liquid state at a specific temperature as a sub-component of an orientation molding polyethylene raw fabric sheet. SOLUTION: A resin composition obtained by mixing 1.0 pt.wt. of an ethylene- propylene copolymer (weight-average molecular weight: 2×104 and a viscosity at 60 deg.C: 210 poises (liquid state)) with 100 pts.wt. of a crystalline high-density polyethylene is melt kneaded at a resin temperature of 200 deg.C by using an isotropic biaxial kneading extruder. Then, the composition is molded to a sheet having a width of 70 mm and a thickness of 2.5 mm by a calendering machine (roll temperature: 90 deg.C), wound, and rolled 10 times by using hot rolls (125 deg.C), thereby obtaining a rolled polyethylene raw fabric sheet. An oriented polyethylene sheet having an orientation temperature of 100 deg.C, an orientation ratio of first stage of 2.0 times, an orientation ratio of second stage of 1.6 times, and a total orientation ratio of 32 times is formed by a hot air heating type orienting machine.
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