Multilayer low-density polyethylene (MMLDPE) yog cov khoom siv polymer tsim los ntawm kev tsim thiab ua tiav ob lossis ntau txheej ntawm polyethylene lossis hloov polymers nrog cov yam ntxwv sib txawv. Lub hauv paus ntawm nws cov muaj pes tsawg leeg yog nyob rau hauv kev xaiv thiab kev sib txuas ntawm cov khoom siv rau txhua txheej ua haujlwm raws li daim ntawv thov, thiab ua kom muaj kev sib raug zoo ntawm interlayer thiab kev sib koom ua ke los ntawm cov txheej txheem molding tsim nyog, yog li kov yeej cov kev ua haujlwm tsis zoo ntawm ib qho - txheej qis - ntom polyethylene (LDPE).
Hais txog kev xaiv cov khoom siv, cov qauv ntawm MMLDPE feem ntau yog siv qis-polyethylene ntom ntom lossis nws cov khoom siv los ua cov matrix, suav nrog cov pa LDPE, linear low-density polyethylene (LLDPE), thiab metallocene-catalyzed low-density{1}PE (LDPE). Cov ntaub ntawv no muaj qhov sib txawv ntawm qhov sib txawv, qhov yooj yim, thiab cua sov- sealing zog vim qhov sib txawv ntawm lawv cov qauv saw molecular. Cov txheej txheem tseem ceeb feem ntau siv LLDPE lossis m-LDPE kom sib npaug zoo txhua yam muaj zog thiab kev ua haujlwm ntws. Cov khaubncaws sab nraud povtseg suav nrog cov ntaub ntawv thaiv (xws li ethylene-vinyl cawv copolymer EVOH, polyamide PA), huab cua- tiv thaiv kev hloov pauv, tiv thaiv- cov tshuaj tiv thaiv, lossis cov pob tshab hloov kho LDPE, nyob ntawm kev tiv thaiv lossis kev ua cov hom phiaj, txhawm rau txhim kho cov pa oxygen thiab dej noo.
Layer sequence design yog ib qho tseem ceeb ntawm txoj kev sib xyaw. Ib qho qauv zoo ib yam yog hom sandwich, piv txwv li, txheej txheej txheej ntawm pob tshab lossis huab cua- tiv taus hloov LDPE, ib txheej nruab nrab ntawm LLDPE / m-LDPE nrog zoo toughness thiab tshav kub- sealing zog, thiab ib txheej sab hauv lossis nruab nrab barrier. Qhov chaw ntawm txheej txheej thaiv yuav tsum tau txiav txim siab raws li cov txheej txheem permeation thiab kev ua tau zoo, feem ntau muab tso rau nruab nrab thiab sab hauv txheej kom tsis txhob ntog txhua yam puas tsuaj thiab ua rau txoj kev permeation luv. Qhov sib piv ntawm cov txheej thicknesses sib txawv yuav tsum tau ua kom zoo dua los ntawm kev simulation thiab kev sim kom ntseeg tau tias muaj kev sib npaug ntawm cov khoom siv thauj khoom, kev ua haujlwm txaus, thiab tsis muaj kev cuam tshuam rau cov cua sov- sealing kev ua tau zoo.
Cov txheej txheem molding feem ntau yog siv cov co-extrusion technology, uas yog txoj kev ncaj ncees thiab ua tau zoo tshaj plaws kom ua tiav ntau txheej txheej. Lub co-extrusion system yog nruab nrog ntau lub extruders, uas cais yaj thiab xa cov ntaub ntawv raw rau txhua txheej rau cov khoom sib xyaw. Los ntawm kev tswj qhov kub thiab txias thiab ntws channel tsim, laminar flow superposition thiab interfacial fusion tiav. Qhov zoo ntawm cov txheej txheem no yog tias nws tuaj yeem ua kom tiav cov txheej txheem ntawm ntau- txheej txheej hauv ib txheej txheem molding, tsis txhob siv cov nplaum nplaum, txo cov kuab tshuaj residue, thiab txhim kho interlayer bonding zog. Rau qee cov qauv tshwj xeeb (xws li cov uas xav tau ultra- siab barrier lossis conductive functions), post-txoj kev sib xyaw kuj siv tau, kev sib txuas ua ntej- tsim ib qho - txheej zaj duab xis los ntawm kub nias lossis nplaum txheej. Txawm li cas los xij, kev saib xyuas yuav tsum tau them rau kev sib txuas ntawm lub ntsej muag thiab tag nrho cov thickness tswj.
Thaum lub sij hawm txheej txheem muaj pes tsawg leeg, cov ntaub ntawv compatibility thiab ua qhov rais yuav tsum tau muab xam comprehensively. Qhov sib txawv tseem ceeb hauv melting kub, viscosity, thiab shrinkage tus nqi ntawm cov polymers sib txawv tau yooj yim ua rau interlayer kev nyuaj siab concentration los yog txias warping. Yog li ntawd, kev sib txuas lus sib txuas yuav tsum tau txhim kho los ntawm kev tsim kho kom zoo -tuning lossis siv cov compatibilizers. Tsis tas li ntawd, kev ntsuas hauv online thickness thiab kev tawm tswv yim tswj qhov system tuaj yeem saib xyuas qhov sib xws ntawm txhua txheej txheej tuab hauv lub sijhawm, ua kom ruaj khov ua tiav cov khoom tiav.
Hauv cov ntsiab lus, txoj kev sib xyaw ua ke ntawm MMLDPE yog ua raws li kev ua haujlwm - kev xaiv cov khoom siv, kev tshawb fawb txheej txheej ua ntu zus thiab cov txheej txheem molding precision xws li co-extrusion. Los ntawm kev sib koom ua ke ntawm cov qauv tsim thiab kev tswj cov txheej txheem, nws ua tiav ntau- kev sib koom ua ke thiab kev tsim khoom tsim tau, muab cov khoom siv txhim khu kev qha rau siab - kawg ntim thiab kev lag luam.