Stretch film ndi zinthu za polima zomwe zimagwiritsidwa ntchito kwambiri pakuyika zinthu. Njira yake yophatikizira imakhudza mwachindunji magwiridwe antchito ndi mpikisano wamsika wazinthu. Ndi kusintha kwa zofunikira zachitetezo cha chilengedwe komanso kusiyanasiyana kwa zosowa zamapaketi, ukadaulo wa kaphatikizidwe ka filimu yotambasulira umakhalanso wakupanga zatsopano. Nkhaniyi ifotokoza mozama za kaphatikizidwe ka filimu yotambasulira kuchokera ku zopangira zopangira, polima mpaka ukadaulo wopanga filimu.
Kusankha kwazinthu zopangira: maziko amatsimikizira magwiridwe antchito
Zopangira zazikulu za filimu yotambasula ndi polyethylene (PE). Kutengera cholinga, otsika-kachulukidwe polyethylene (LDPE), linear low-density polyethylene (LLDPE) kapena high-density polyethylene (HDPE) angasankhidwe. LDPE imapatsa filimuyo kusinthasintha kwabwino komanso kuwonekera, pomwe LLDPE imatha kupititsa patsogolo kulimba kwamphamvu komanso kukana nkhonya. M'zaka zaposachedwa, metallocene polyethylene (mPE) yomwe imateteza zachilengedwe pang'onopang'ono yasanduka filimu yomwe anthu amaikonda kwambiri- chifukwa cha mawonekedwe ake ofanana a ma molekyulu komanso momwe amachitira bwino. Kuphatikiza apo, kukwaniritsa zosowa zenizeni, zinthu zina zimawonjezera zowonjezera monga tackifiers, UV inhibitors kapena antioxidants.
Njira ya polymerization: kuchokera ku monomer kupita ku polima
The synthesis wa polyethylene makamaka zimatheka mwa polymerization anachita ethylene. Njira zodziwika bwino zimaphatikizira-kupanikizika kwambiri kwa polymerization ndi kutsika{{2}kutsika kwa polymerization. High{{4}pressure polymerization (monga tubular method kapena ketulo) ndiyoyenera kupanga LDPE. The anachita zinthu ndi ankhanza ndi ufulu ankafuna kwambiri polymerization chofunika pansi pa kutentha ndi kuthamanga. Low{{7}pressure polymerization (monga gasi gawo kapena njira yothetsera) amagwiritsidwa ntchito kupanga LLDPE ndi HDPE. Ziegler-Natta catalyst kapena metallocene catalyst amagwiritsidwa ntchito. Zochita zinthu ndi wofatsa ndi maselo kulemera kugawa ndi controllable. Njira zamakono zimagwiritsa ntchito ukadaulo wa gasi{12}}phase fluidized bed kulimbikitsa kupanga bwino komanso kuchepetsa kugwiritsa ntchito mphamvu.
Ukadaulo wopanga mafilimu: masewera pakati pa kuwomba ndi kuponya filimu
Kupanga kuzimata filimu makamaka zimadalira njira ziwiri: kuwomba akamaumba ndi kuponya filimu. Njira yopangira nkhonya imawomba utomoni wosungunuka kukhala filimu ya tubular kupyolera mu mutu wa annular kufa, ndiyeno umazizira, kuukoka ndi kuugwedeza. Njirayi ndiyotsika-yotsika mtengo ndipo ndiyoyenera kupanga-zopanga zazikulu, koma kufanana kwa makulidwe a kanema ndikotsika pang'ono. Njira yopangira filimuyi imagwiritsa ntchito mutu wakufa kuti utulutse filimuyo, yomwe imapangidwa mofulumira ndi chogudubuza chozizira. Chomalizidwacho chimakhala ndi makulidwe a yunifolomu komanso kuwonekera kwambiri, koma ndalama zogulira zida ndi zazikulu. M'zaka zaposachedwa, ukadaulo-wosiyanasiyana{8}}wakhala wofala kwambiri. Ndi superimposing zigawo utomoni ndi katundu zosiyanasiyana, mphamvu mkulu, mkulu transparency ndi mamasukidwe akayendedwe zabwino chingapezeke pa nthawi yomweyo.
Njira yoteteza chilengedwe: yowonongeka komanso yobwezeretsanso
Ndi kukhwimitsa kwa malamulo a chilengedwe padziko lonse lapansi, ukadaulo wa kaphatikizidwe ka filimu yotambasula ukulowera pakuwonongeka komanso kukonzanso kosavuta. Kugwiritsa ntchito - polyethylene yochokera ku bio (monga PE yopangidwa kuchokera ku nzimbe ethanol) ndi zowonjezera zowonongeka zikulowa m'malo mwa zinthu zakale za petrochemical. Nthawi yomweyo, kuchepetsa kutulutsa kwachilengedwe kwachilengedwe (VOCs) pakuwongolera kaphatikizidwe kameneka kwakhalanso chidwi chamakampani.
Ukadaulo wophatikizika wa filimu yotambasula umaphatikiza kupita patsogolo kwa magawo angapo a chemistry ya polima, uinjiniya wazinthu ndi sayansi yachilengedwe. M'tsogolomu, ndi kupambana kwa zowonjezera zatsopano ndi njira zobiriwira, machitidwe ndi kukhazikika kwa filimu yotambasula zidzapitilizidwa bwino, ndikupereka mayankho ogwira mtima pamakampani opanga ma CD padziko lonse lapansi.
