EVOH yog dab tsi?
Hauv kev lag luam ntim khoom noj, siv cov khoom sib xyaw ua ke uas ua kom lub neej ntev txee yog ib qho tseem ceeb ntawm kev ua kom muaj kev ruaj ntseg ntawm cov khoom thiab khaws cov saj ntawm cov khoom noj. Tsis tas li ntawd, siv cov khoom ntim khoom uas ua rau lub neej ntev ntawm cov khoom txee tuaj yeem txo cov khoom pov tseg ntawm cov khoom puas tsuaj, thiab tsim lub qhov rais ntev dua rau cov khw muag khoom noj rau cov khoom lag luam ua ntej nws mus txog ntawm cov neeg siv khoom. Ib txoj hauv kev zoo kom ua tiav qhov no yog los ntawm kev siv cov khoom ntim uas txo cov pa oxygen uas nkag mus rau hauv cov yas, xws li EVOH, muab cov khoom siv rau hauv cov txheej txheem ntau txheej coextruded rollstock, lossis cov txheej txheem extrusion laminated.
Thaum cov khoom siv thermoplastic resin ib txwm muaj, xws li polypropylene, polyethylene thiab HIPS, txhua tus muaj qee qhov kev cuam tshuam ntawm cov khoom, lawv feem ntau tsis pom zoo li "barrier" cov ntaub ntawv. Polypropylene, piv txwv li, yog ib qho zoo heev noo noo barrier tab sis tsis ua tau zoo thaum nws los txog rau oxygen permeability. Txhawm rau tiv thaiv cov ntsiab lus ntawm lub ntim los ntawm ob qho tib si oxygen thiab noo noo, cov khoom thaiv yuav tsum tau muab tso rau hauv cov ntawv sib xyaw - thiab qhov no yog cov khoom siv xws li EVOH tuaj.
Yog li EVOH zaj duab xis yog dab tsi thiab nws yuav ua li cas thiaj li txhawb nqa lub txee lub neej ntawm cov khoom ntim khoom noj?
EVOH sawv cev rau Ethylene-vinyl cawv copolymer thiab yog hloov tau, siv lead ua ntshiab, glossy thermoplastic copolymer. Cov khoom no muaj qhov zoo tshaj plaws flex-crack tsis kam, thiab muaj kev tiv thaiv siab rau hydrocarbons, roj thiab cov kuab tshuaj organic. EVOH paub txog tias muaj qee qhov kev tiv thaiv zoo tshaj plaws rau cov pa roj xws li oxygen, nitrogen, thiab carbon dioxide uas ua rau nws tshwj xeeb tshaj yog haum rau ntim khoom noj, tshuaj, tshuaj pleev ib ce, thiab lwm yam khoom puas tsuaj. Thaum piv rau lwm cov yeeb yaj kiab, EVOH raug suav hais tias muaj qhov cuam tshuam zoo tshaj plaws. Txawm li cas los xij, thaum raug cov dej noo, EVOH poob nws cov khoom siv roj zoo. Vim li no, EVOH feem ntau yog siv nyob rau hauv ib tug multilayer co-extruded zaj duab xis qauv nrog cov ntaub ntawv xws li HDPE, PP thiab PET, tag nrho cov uas muaj superior noo noo barrier zog.
Cia peb saib peb cov khoom EVOH:
