It is to provide a porous film which is excellent in gas permeability (air permeability) and moisture permeability (water vapor permeability), and is excellent in anti-leakage properties and anti-bleeding properties against a liquid, hiding properties and masking properties at an adhesion portion, and a process for producing it. A porous film obtained by melting and kneading a resin composition containing a polyolefin resin {component (A)} and a bulking agent {component (B)} as the main components, and a silicone {component (C)}, or a silicone {component (C)} and castor oil {component (D)}, followed by drawing, which shrinks by from 40 to 95% in one direction and expands by from 5 to 40% in a direction transverse thereto, when soaked in a silicone oil of 200 C for 60 seconds, and a process for producing the above porous film, are provided.
本发明旨在提供一种气体渗透性(透气性)和湿气渗透性(
水蒸气渗透性)优异、对液体的防渗漏性和防渗漏性、粘合部分的遮盖性和掩蔽性优异的多孔薄膜及其生产工艺。一种多孔薄膜,通过熔化和捏合一种
树脂组合物而获得,该
树脂组合物的主要成分是聚烯烃
树脂(A 组分)和
膨松剂(B 组分),以及
硅酮(C 组分)或
硅酮(C 组分);和
蓖麻油 {component (D)},然后进行拉伸,当在 200 C 的
硅油中浸泡 60 秒时,在一个方向上收缩 40% 至 95%,在横向上膨胀 5% 至 40%,并提供了生产上述多孔薄膜的工艺。