发明名称 SYSTEM AND METHOD FOR LANGUAGE EDUCATION USING PERSONAL INFORMATION COMMUNICATION TERMINAL
摘要 A uniaxially heat-shrinkable, biaxially oriented, multilayer film having a polypropylene-containing core layer comprising at least 70 wt.% of said multilayer film and optionally, at least one polyolefin- containing skin layer adjacent said core layer, is prepared by biaxially orienting a coextrudate and thereafter orienting said coextrudate by stretching 10 to 40 % in the machine direction. The core layer contains isotactic polypropylene and a sufficient amount of syndiotactic polypropylene to inhibit uniaxial heat shrinkage at temperatures below 50 °C. The skin layer can be selected from the group consisting of polypropylene, ethylene-propylene copolymer, polyethylene, and ethylene- propylene-butylene terpolymer.
申请公布号 KR20010112704(A) 申请公布日期 2001.12.21
申请号 KR20000032076 申请日期 2000.06.12
申请人 KIM, YOUNG HO 发明人 KIM, YOUNG HO
分类号 H04W4/00 主分类号 H04W4/00
代理机构 代理人
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