A process for producing a foam comprising subjecting a foaming composition to foaming conditions, said foaming composition comprising (A) from 1 to 99% by weight, based on the total weight of (A) and (B), of a random copolymer comprising units derived from propylene, from 0.1 to 15 mol% of units derived from a non-conjugated diene represented by formula (I):
wherein R1, R2, R3, R4, and R5 each independently represents a hydrogen atom or an alkyl group having from 1 to 8 carbon atoms; and n represents a number of from 2 to 10,
and, if desired, up to 4 mol% of units derived from ethylene, said random copolymer having a degree of crystallinity of at least 20% as measured by X-ray diffractometry, a melt flow rate of from 0.01 to 200 g/10 min as measured according to ASTM D1238-1986, and an elastic modulus of from 1,000 to 15,000 kg/cm2 as measured according to JIS K-7203, and (B) from 99 to 1% by weight, based on the total weight of (A) and (B), of a homopolymer of an a-olefin having from 3 to 12 carbon atoms or a copolymer mainly comprising said a-olefin, wherein the melting point of the minor resin component (A) or (B) is less than 15 °C higher than that of the major resin component (A) or (B), and the ratio of the melt flow rate of resin component (A) to that of (B) is between 0.02 and 50, utilizes a foaming composition having a low melt viscosity and provides a uniform foam having a uniform cell size and a high foaming rate.
一种生产泡沫的工艺,包括将发泡组合物置于发泡条件下,所述发泡组合物包括 (A) 以(A)和(B)的总重量为基准,按重量计为 1 至 99%的无规共聚物,该共聚物由衍生自
丙烯的单元、0.1 至 15 摩尔%的衍生自式(I)代表的非共轭二烯的单元组成:
其中 R1、R2、R3、R4 和 R5 各自独立地代表氢原子或具有 1 至 8 个碳原子的烷基;n 代表 2 至 10 的数字、
如果需要,还有高达 4 摩尔%的
乙烯衍生单元,所述无规共聚物的结晶度经 X 射线衍射仪测量至少为 20%,熔体流动速率经 X 射线衍射仪测量为 0.(B) 以(A)和(B)的总重量为基准,以重量计,具有 3 至 12 个碳原子的 a-olefin 均聚物或主要由所述 a-olefin 组成的共聚物的 99 至 1%、其中次要
树脂组分(A)或(B)的熔点比主要
树脂组分(A)或(B)的熔点高 15℃以下,
树脂组分(A)的熔体流动速率与(B)的熔体流动速率之比介于 0.02 至 50 之间,利用这种发泡组合物具有较低的熔体粘度,并提供具有均匀泡孔尺寸和较高发泡速率的均匀泡沫。