| 摘要 |
The present invention is directed at polypropylene compositions containing a high level of filler, at a calendering process which uses the compositions to produce polypropylene films and sheets, and at the film or sheet produced from that process. The process of manufacturing polypropylene film involves formulating a polypropylene composition containing a resin, filler, matrix modifier, and processing aid. The resin comprises polypropylene resin ranging in concentration from about 100 to about 70 parts per hundred parts by weight of resin (PHR), and polyethylene resin ranging in concentration from about 0 to 30 PHR. The matrix modifier amounts to about 2 to 40 PHR. The filler ranges in concentration from about 0 to 450 PHR. The processing aid ranges in concentration for about 0 to 5.0 PHR. The composition is then mixed to obtain a homogeneous and plasticized mixture. Next, the mixture is calendered into a film using a calender unit having a multiplicity of rolls, the rolls having a surface temperature between 200 DEG C. and 250 DEG C. After calendering, the film is removed using take-off rolls and cooled to ambient temperature.
|
