Pali mitundu yambiri ya mapepala apulasitiki omwe amagwiritsidwa ntchito mosiyanasiyana. Pakali pano, mitundu yayikulu ndi polyvinyl kolorayidi, polystyrene ndi polyester (PET). Tsamba la PET limagwira ntchito bwino ndipo limakwaniritsa zofunikira zaukhondo wadziko pazinthu zowumbidwa komanso zofunikira zapadziko lonse lapansi zoteteza chilengedwe. Iwo ali pa tebulo lachitetezo cha chilengedwe. Pakadali pano, kulongedza kumayenera kukwaniritsa zofunikira zachitetezo cha chilengedwe ndi zobwezeretsanso, kotero kufunikira kwa mapepala a PET kukukulirakulira. Nkhaniyi ikufotokoza makamaka za kupanga ndi mavuto omwe amapezeka pamasamba a PET.
Tekinoloje yopanga mapepala a PET:
(1) PET pepala
Monga mapulasitiki ena, katundu wa pepala la PET ndi ofanana kwambiri ndi kulemera kwa maselo. Kulemera kwa maselo kumatsimikiziridwa ndi kukhuthala kwamkati. Apamwamba kukhuthala kwachibadwa, ndi bwino thupi ndi mankhwala katundu, koma fluidity osauka ndi zovuta kupanga. Kutsika kwa mamasukidwe amkati, kumapangitsa kuti thupi ndi mankhwala aziwoneka bwino komanso mphamvu zake. Chifukwa chake, kukhuthala kwamkati kwa pepala la PET kuyenera kukhala 0.8dl/g-0.9dl/g.
(2) Kupanga njira yoyendera
Chachikuluzida zopangira mapepala a PETzikuphatikizapo crystallization nsanja, kuyanika nsanja, extruders, kufa mitu, atatu-roll calenders ndi coilers. The ndondomeko kupanga ndi: zopangira crystallization-kuyanika-extrusion plasticization-extrusion akamaumba-calendering ndi kuumba-zokhotakhota mankhwala.
1. Crystallization. Magawo a PET amatenthedwa ndikuwunikiridwa munsanja ya crystallization kuti agwirizane ndi mamolekyu, kenako amawonjezera kutentha kwa galasi la magawowo kuti apewe kumamatira ndi kutsekeka kwa hopper panthawi yowumitsa. Crystallization nthawi zambiri ndi gawo lofunikira. Crystallization imatenga mphindi 30-90 ndipo kutentha kumakhala pansi pa 149 ° C.
2.Unikani. Pakutentha kwambiri, madzi amasungunuka ndi kuwononga PET, zomwe zimapangitsa kuchepa kwa khalidwe lake, ndipo mphamvu zake, makamaka mphamvu zowonongeka, zidzachepa pamene kulemera kwa maselo kumachepa. Choncho, musanasungunuke ndi kutulutsa, PET iyenera kuyanika kuti muchepetse chinyezi, chomwe chiyenera kukhala chocheperapo 0.005%. Dehumidification dryer imagwiritsidwa ntchito poyanika. Chifukwa cha hygroscopicity ya zinthu za PET, madzi akalowa mkati mwa kagawo kakang'ono, zomangira zamamolekyu zimapangidwa, ndipo gawo lina lamadzi lidzalowa mkati mwa kagawo, kupangitsa kuyanika kukhala kovuta. Choncho, mpweya wotentha wamba sungagwiritsidwe ntchito. Mpweya wotentha wa mame umayenera kukhala wotsika kuposa -40C, ndipo mpweya wotentha umalowa mu chowumitsira chowumitsa kudzera mu dera lotsekedwa kuti uyanike mosalekeza.
3. Finyani. Pambuyo pa crystallization ndi kuyanika, PET imasandulika kukhala polima yokhala ndi malo osungunuka. Kutentha kwa polima ndikwambiri komanso kuwongolera kutentha kumakhala kocheperako. Chotchinga chotchinga cha poliyesitala chimagwiritsidwa ntchito kulekanitsa tinthu tating'ono tomwe timasungunuka, zomwe zimathandiza kumeta ubweya wautali ndikuwonjezera kutulutsa kwa extruder. Milomo yosinthika imafa ndi ndodo yowongoka. Mutu wa nkhungu ndi tapered. Othamanga othamanga komanso milomo yopanda zokanda imasonyeza kuti mapeto ayenera kukhala abwino. Chotenthetsera nkhungu chimakhala ndi ngalande ndi ntchito zoyeretsa.
4.Kuzizira ndi kuumba. Pambuyo pa kusungunuka kumatuluka pamutu, mwachindunji amalowetsamo katatu-roll calender kwa calendering ndi kuziziritsa. Mtunda pakati pa makalenda atatu odzigudubuza ndi mutu wa makina nthawi zambiri umasungidwa pafupifupi 8cm, chifukwa ngati mtunda uli waukulu kwambiri, bolodi imagwedezeka mosavuta ndikukwinyika, zomwe zimapangitsa kuti zisawonongeke. Kuonjezera apo, chifukwa cha mtunda wautali, kutentha kwa kutentha ndi kuziziritsa kumakhala pang'onopang'ono, ndipo kristalo imasanduka yoyera, yomwe si yoyenera kugudubuza. Gawo la calendering la katatu limapangidwa ndi odzigudubuza apamwamba, apakati ndi apansi. Mtsinje wa wodzigudubuza wapakati umakhazikika. Panthawi yoziziritsa ndi kusungirako, kutentha kwa pamwamba pa chogudubuza ndi 40°c-50c. Tsinde la odzigudubuza apamwamba ndi apansi amatha kusunthira mmwamba ndi pansi.
Nthawi yotumiza: Sep-28-2023
