Blownfilm grade showing superior stiffness, transparency and processing behaviour
申请人:Borealis AG
公开号:EP2338930A1
公开(公告)日:2011-06-29
Extrusion blown film comprising a polypropylene composition, said polypropylene composition comprises a random propylene copolymer, a high melt strength polypropylene, a polypropylene and optionally a α-nucleating agent, wherein
(a) the random propylene copolymer comprises units derived from propylene and at least another C2 to C20 α-olefin,
(b) the high melt strength polypropylene has a branching index g' of less than 1.0,
(c) the polypropylene has a MFR2 (230 °C) of at least 400 g/10min,
wherein further
• the random propylene copolymer (R-PP), the high melt strength polypropylene (HMS-PP), and the polypropylene (B) are chemically different, and
• the extrusion melt blown film fulfills the equation Tm-Tc≤30
wherein
Tm
is the melting temparetaure [°C] making up more than 50% of the total melting enthalpy Hm of the extrusion melt blown film or of the polypropylene composition measured by DSC according to ISO 11357-3;
Tc
is the crystallization temperature [°C] of the extrusion melt blown film or of the polypropylene composition measured by DSC according to ISO 11357-3.
由聚丙烯组合物组成的挤出吹塑薄膜,所述聚丙烯组合物包括无规丙烯共聚物、高熔体强度聚丙烯、聚丙烯和可选α-成核剂,其中
(a) 无规丙烯共聚物由丙烯和至少另一种 C2 至 C20 α-烯烃衍生单元组成、
(b) 高熔体强度聚丙烯的支化指数 g'小于 1.0、
(c) 聚丙烯的 MFR2(230 °C)至少为 400 克/10 分钟、
其中
- 无规丙烯共聚物(R-PP)、高熔体强度聚丙烯(HMS-PP)和聚丙烯(B)的化学性质不同,以及
- 挤出熔融吹塑薄膜符合公式 Tm-Tc≤30
其中
Tm
是挤出熔融吹塑薄膜或聚丙烯组合物的总熔融焓 Hm 的 50%以上的熔融温度[°C],由 DSC 根据 ISO 11357-3 测得;
Tc
是挤出熔融吹塑薄膜或聚丙烯组合物的结晶温度[°C],由 DSC 根据 ISO 11357-3 测得。