甘肅纏繞膜早期LLDPE拉(la)(la)伸(shen)(shen)膜(mo)以吹(chui)膜(mo)為(wei)多，從(cong)單(dan)層(ceng)(ceng)(ceng)發展到二層(ceng)(ceng)(ceng)、三層(ceng)(ceng)(ceng)；以流(liu)(liu)延法(fa)生產(chan)LLDPE拉(la)(la)伸(shen)(shen)膜(mo)為(wei)主(zhu)，其流(liu)(liu)程見下圖，這是(shi)因為(wei)流(liu)(liu)延線生產(chan)具有厚薄均(jun)勻、透明(ming)(ming)度(du)高(gao)等(deng)優(you)(you)點，可適用(yong)于(yu)高(gao)倍(bei)率預拉(la)(la)伸(shen)(shen)的(de)要求。由(you)于(yu)單(dan)層(ceng)(ceng)(ceng)流(liu)(liu)延做(zuo)不到單(dan)面粘(zhan)，應用(yong)領域受(shou)到局限。單(dan)、雙層(ceng)(ceng)(ceng)流(liu)(liu)延在材料選擇(ze)上沒有三層(ceng)(ceng)(ceng)流(liu)(liu)延的(de)廣，配方成(cheng)本也高(gao)，所以還是(shi)以三層(ceng)(ceng)(ceng)共(gong)擠的(de)結構較為(wei)理想。優(you)(you)質的(de)拉(la)(la)伸(shen)(shen)膜(mo)應具有透明(ming)(ming)度(du)高(gao)，縱(zong)向(xiang)伸(shen)(shen)長(chang)率高(gao)，屈服點高(gao)，橫向(xiang)撕(si)裂強度(du)高(gao)，穿(chuan)刺性能好等(deng)特(te)點 

    良好的粘性使貨物外面的包裝纏繞膜層與層粘(zhan)(zhan)(zhan)(zhan)在(zai)一起使(shi)貨物(wu)牢固，粘(zhan)(zhan)(zhan)(zhan)性(xing)的獲取(qu)方(fang)法(fa)主要有(you)(you)兩種(zhong)(zhong)：一種(zhong)(zhong)是(shi)在(zai)高(gao)聚(ju)物(wu)里添(tian)加(jia)PIB或(huo)其(qi)母(mu)料(liao)；另(ling)一種(zhong)(zhong)是(shi)摻混VLDPE。PIB為半(ban)透(tou)明(ming)粘(zhan)(zhan)(zhan)(zhan)稠(chou)液體，直(zhi)接添(tian)加(jia)需(xu)有(you)(you)專(zhuan)用設(she)備或(huo)對設(she)備進行改造，一般均(jun)采(cai)用PIB母(mu)料(liao)。PIB的遷出有(you)(you)個過(guo)程，一般要三天，另(ling)外(wai)還(huan)受(shou)溫(wen)度影響，氣(qi)(qi)溫(wen)高(gao)時(shi)粘(zhan)(zhan)(zhan)(zhan)性(xing)強；氣(qi)(qi)溫(wen)低(di)時(shi)不(bu)太(tai)粘(zhan)(zhan)(zhan)(zhan)，經拉伸后粘(zhan)(zhan)(zhan)(zhan)性(xing)大大降低(di)。也(ye)因此成品膜最好(hao)貯(zhu)存(cun)在(zai)一定的溫(wen)度范圍(wei)內(建(jian)議貯(zhu)存(cun)溫(wen)度在(zai)15℃～25℃)。摻混VLDPE，粘(zhan)(zhan)(zhan)(zhan)性(xing)稍差，但對設(she)備沒有(you)(you)特殊要求(qiu)，粘(zhan)(zhan)(zhan)(zhan)性(xing)相(xiang)對穩定，不(bu)受(shou)時(shi)間控(kong)制，但也(ye)受(shou)溫(wen)度影響，氣(qi)(qi)溫(wen)高(gao)于(yu)30℃時(shi)相(xiang)對較粘(zhan)(zhan)(zhan)(zhan)，低(di)于(yu)15℃時(shi)粘(zhan)(zhan)(zhan)(zhan)性(xing)稍差，可通過(guo)調(diao)節粘(zhan)(zhan)(zhan)(zhan)層LLDPE的量，以達到所需(xu)的粘(zhan)(zhan)(zhan)(zhan)度。三層共(gong)擠多采(cai)用這(zhe)種(zhong)(zhong)方(fang)法(fa)。