发明授权
- 专利标题: Process for the production of polypropylene films
- 专利标题(中): 生产聚丙烯薄膜的方法
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申请号: US641637申请日: 1996-05-02
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公开(公告)号: US5716570A公开(公告)日: 1998-02-10
- 发明人: Herbert Peiffer , Gunter Schlogl , Karl-Heinz Kochem , Detlef Busch , Robert Schmidt
- 申请人: Herbert Peiffer , Gunter Schlogl , Karl-Heinz Kochem , Detlef Busch , Robert Schmidt
- 申请人地址: DEX
- 专利权人: Hoechst Aktiengesellschaft
- 当前专利权人: Hoechst Aktiengesellschaft
- 当前专利权人地址: DEX
- 优先权: DEX19515599.8 19950502
- 主分类号: B29C47/06
- IPC分类号: B29C47/06 ; B29C47/04 ; B29C47/14 ; B29C55/12 ; B29C69/00 ; B29K23/00 ; B29L7/00 ; B29L9/00 ; B29C47/16 ; B29C55/14
摘要:
A process for the production of biaxially oriented polypropylene films which include at least one layer is described, in which a propylene polymer B is heated in an extruder and the melt of the propylene polymer B is extruded through a flat sheet die and the melt emerging from the flat sheet die is taken off on one or more rolls and is solidified to give a prefilm and this prefilm is stretched in the longitudinal and transverse direction. A propylene polymer or a propylene polymer mixture A is heated and melted in a second extruder and the melt of the propylene polymer or of the propylene polymer mixture A is fed to the two sides of the propylene polymer melt B so that both melts are extruded together and simultaneously through the flat sheet die. The propylene polymer or the propylene polymer mixture A forms the edge region of the film during the production process, and the edge regions including the propylene polymer or the propylene polymer mixture A are cut off after the longitudinal and transverse stretching of the film.
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