塑料(liao)薄膜的生產工(gong)藝

對(dui)塑料薄膜(mo)的(de)(de)(de)生(sheng)(sheng)(sheng)產(chan)工(gong)藝而言，共(gong)有擠(ji)(ji)(ji)(ji)出吹膜(mo)法(fa)、擠(ji)(ji)(ji)(ji)出流涎(xian)(xian)法(fa)、溶劑流涎(xian)(xian)法(fa)、壓(ya)延(yan)法(fa)等多(duo)種(zhong)，而這些工(gong)藝之中(zhong)，擠(ji)(ji)(ji)(ji)出流涎(xian)(xian)法(fa)生(sheng)(sheng)(sheng)產(chan)的(de)(de)(de)薄膜(mo)由于(yu)縱橫向性(xing)能平衡(heng)、無(wu)內(nei)應(ying)(ying)力(li)、熱(re)封(feng)性(xing)優的(de)(de)(de)特點(dian)最適(shi)宜用(yong)(yong)(yong)于(yu)熱(re)封(feng)。但是擠(ji)(ji)(ji)(ji)出流涎(xian)(xian)設(she)備投資(zi)大(da)(da)，限制(zhi)了實際(ji)的(de)(de)(de)使(shi)(shi)(shi)用(yong)(yong)(yong)率，使(shi)(shi)(shi)用(yong)(yong)(yong)面較廣(guang)的(de)(de)(de)是擠(ji)(ji)(ji)(ji)出吹膜(mo)法(fa)生(sheng)(sheng)(sheng)產(chan)的(de)(de)(de)熱(re)封(feng)膜(mo)，應(ying)(ying)當(dang)注(zhu)意的(de)(de)(de)是擠(ji)(ji)(ji)(ji)出吹膜(mo)時(shi)(shi)的(de)(de)(de)拉(la)(la)伸比(bi)(bi)和牽引比(bi)(bi)都應(ying)(ying)當(dang)較小一點(dian)，且二(er)者應(ying)(ying)平衡(heng)，防止因(yin)拉(la)(la)伸比(bi)(bi)或牽引比(bi)(bi)過大(da)(da)，引起過多(duo)的(de)(de)(de)塑料分子因(yin)拉(la)(la)力(li)作(zuo)用(yong)(yong)(yong)而產(chan)生(sheng)(sheng)(sheng)定向結晶(jing)，使(shi)(shi)(shi)薄膜(mo)喪失熱(re)封(feng)性(xing)。在(zai)生(sheng)(sheng)(sheng)產(chan)耐(nai)熱(re)性(xing)較好(hao)的(de)(de)(de)聚丙烯(xi)熱(re)封(feng)用(yong)(yong)(yong)膜(mo)時(shi)(shi)，應(ying)(ying)使(shi)(shi)(shi)用(yong)(yong)(yong)水冷卻法(fa)的(de)(de)(de)下(xia)吹法(fa)擠(ji)(ji)(ji)(ji)吹膜(mo)，才能使(shi)(shi)(shi)PP膜(mo)有良好(hao)的(de)(de)(de)熱(re)封(feng)和透(tou)明性(xing)。溶劑流涎(xian)(xian)法(fa)因(yin)需要使(shi)(shi)(shi)用(yong)(yong)(yong)到大(da)(da)量(liang)(liang)的(de)(de)(de)溶劑，成(cheng)本貴，溶劑回收設(she)備大(da)(da)、投資(zi)大(da)(da)、耗費大(da)(da)，一般(ban)極少使(shi)(shi)(shi)用(yong)(yong)(yong)，只在(zai)生(sheng)(sheng)(sheng)產(chan)極薄、高(gao)性(xing)能電(dian)子包裝膜(mo)時(shi)(shi)才使(shi)(shi)(shi)用(yong)(yong)(yong)。壓(ya)延(yan)法(fa)只使(shi)(shi)(shi)用(yong)(yong)(yong)在(zai)PVC薄膜(mo)、片材上，對(dui)熔體流動性(xing)很好(hao)的(de)(de)(de)聚烯(xi)烴塑料而言，只適(shi)用(yong)(yong)(yong)于(yu)無(wu)機填充量(liang)(liang)較大(da)(da)時(shi)(shi)才使(shi)(shi)(shi)用(yong)(yong)(yong)。