塑料薄(bo)膜的(de)生產工藝

對塑(su)料薄膜(mo)(mo)(mo)(mo)(mo)的(de)(de)(de)(de)生(sheng)(sheng)產(chan)工藝(yi)而(er)(er)言(yan)，共(gong)有(you)擠(ji)出(chu)(chu)吹膜(mo)(mo)(mo)(mo)(mo)法(fa)(fa)、擠(ji)出(chu)(chu)流涎(xian)法(fa)(fa)、溶(rong)劑(ji)(ji)流涎(xian)法(fa)(fa)、壓(ya)延法(fa)(fa)等多種，而(er)(er)這些工藝(yi)之中(zhong)，擠(ji)出(chu)(chu)流涎(xian)法(fa)(fa)生(sheng)(sheng)產(chan)的(de)(de)(de)(de)薄膜(mo)(mo)(mo)(mo)(mo)由于(yu)(yu)縱橫向(xiang)性(xing)(xing)(xing)(xing)能(neng)平衡(heng)、無內應力、熱(re)封(feng)(feng)性(xing)(xing)(xing)(xing)優的(de)(de)(de)(de)特點最適宜用(yong)(yong)(yong)于(yu)(yu)熱(re)封(feng)(feng)。但是(shi)擠(ji)出(chu)(chu)流涎(xian)設(she)(she)備投資大，限制了實際(ji)的(de)(de)(de)(de)使(shi)用(yong)(yong)(yong)率，使(shi)用(yong)(yong)(yong)面(mian)較(jiao)(jiao)廣的(de)(de)(de)(de)是(shi)擠(ji)出(chu)(chu)吹膜(mo)(mo)(mo)(mo)(mo)法(fa)(fa)生(sheng)(sheng)產(chan)的(de)(de)(de)(de)熱(re)封(feng)(feng)膜(mo)(mo)(mo)(mo)(mo)，應當(dang)注意的(de)(de)(de)(de)是(shi)擠(ji)出(chu)(chu)吹膜(mo)(mo)(mo)(mo)(mo)時(shi)的(de)(de)(de)(de)拉伸比(bi)和(he)牽引比(bi)都應當(dang)較(jiao)(jiao)小(xiao)一(yi)點，且二者(zhe)應平衡(heng)，防止(zhi)因(yin)拉伸比(bi)或牽引比(bi)過(guo)(guo)大，引起(qi)過(guo)(guo)多的(de)(de)(de)(de)塑(su)料分子因(yin)拉力作用(yong)(yong)(yong)而(er)(er)產(chan)生(sheng)(sheng)定向(xiang)結晶，使(shi)薄膜(mo)(mo)(mo)(mo)(mo)喪失熱(re)封(feng)(feng)性(xing)(xing)(xing)(xing)。在生(sheng)(sheng)產(chan)耐熱(re)性(xing)(xing)(xing)(xing)較(jiao)(jiao)好的(de)(de)(de)(de)聚丙烯(xi)熱(re)封(feng)(feng)用(yong)(yong)(yong)膜(mo)(mo)(mo)(mo)(mo)時(shi)，應使(shi)用(yong)(yong)(yong)水(shui)冷(leng)卻法(fa)(fa)的(de)(de)(de)(de)下吹法(fa)(fa)擠(ji)吹膜(mo)(mo)(mo)(mo)(mo)，才能(neng)使(shi)PP膜(mo)(mo)(mo)(mo)(mo)有(you)良好的(de)(de)(de)(de)熱(re)封(feng)(feng)和(he)透(tou)明性(xing)(xing)(xing)(xing)。溶(rong)劑(ji)(ji)流涎(xian)法(fa)(fa)因(yin)需(xu)要(yao)使(shi)用(yong)(yong)(yong)到大量的(de)(de)(de)(de)溶(rong)劑(ji)(ji)，成本貴(gui)，溶(rong)劑(ji)(ji)回收(shou)設(she)(she)備大、投資大、耗(hao)費大，一(yi)般極少使(shi)用(yong)(yong)(yong)，只(zhi)在生(sheng)(sheng)產(chan)極薄、高性(xing)(xing)(xing)(xing)能(neng)電子包裝膜(mo)(mo)(mo)(mo)(mo)時(shi)才使(shi)用(yong)(yong)(yong)。壓(ya)延法(fa)(fa)只(zhi)使(shi)用(yong)(yong)(yong)在PVC薄膜(mo)(mo)(mo)(mo)(mo)、片材上(shang)，對熔體流動性(xing)(xing)(xing)(xing)很(hen)好的(de)(de)(de)(de)聚烯(xi)烴塑(su)料而(er)(er)言(yan)，只(zhi)適用(yong)(yong)(yong)于(yu)(yu)無機填充(chong)量較(jiao)(jiao)大時(shi)才使(shi)用(yong)(yong)(yong)。