Yog vim li cas rau kev hloov xim ntawm cov kav dej pvc
Dec 31, 2022
Cov kav dej PVC yuav hloov xim vim muaj ntau yam laj thawj thaum siv. Thaum cov neeg siv khoom pom qhov hloov pauv ntawm cov kav dej PVC, lawv yuav thuam qhov zoo ntawm cov kav dej PVC. Qhov tseeb, vim li cas rau kev hloov xim ntawm cov kav dej PVC tsis yog qhov zoo ntawm cov kav dej PVC xwb. Cia peb saib seb yog vim li cas rau qhov discoloration ntawm PVC kav.
1. PVC khoom zoo
Vim tias muaj cov tshuaj tertiary chlorine thiab allyl chloride nyob rau hauv cov qauv molecular ntawm PVC, PVC cov kav dej yog nquag decompose thaum lub sij hawm tsim khoom thiab tom qab siv, ua rau cov kav dej pib hloov xim. Qhov kev txiav txim ntawm cov xim hloov yog: dawb, liab, daj, liab, dub (Carbonization), yog li qhov zoo ntawm PVC, qhov zoo ntawm stabilizer (kom tswj decomposition) thiab tus nqi tseem ceeb heev.
2. Discoloration induced los ntawm unqualified titanium dioxide
Feem ntau muaj ob hom qauv: anatase thiab rutile. Vim nws cov qauv sib txawv, siv lub zog thiab kev laus ua haujlwm. Nws yuav tsum yog hom rutile siv los ua PVC yeeb nkab. Txawm li cas los xij, vim muaj teeb meem zoo ntawm qee cov tuam txhab lossis cov txheej txheem tsis sib xws, cov xim tsis zoo (greying) tshwm sim nyob rau hauv cov xwm txheej photocatalytic.
3. Sulfur pollution thiab lead ntsev stabilizer, cadmium stabilizer
Nrog rau txoj kev loj hlob ntawm kev lag luam, cov teeb meem ntawm cov kua qaub nag thiab sulfide cov pa phem tau dhau los ua qhov hnyav dua, thiab cov profiles yuav tuaj yeem tiv nrog sulfide thaum lub sij hawm cia thiab kev thauj mus los, yog li qhov ua tau ntawm sulfide muaj kuab paug yog siab heev. Cov khoom tsim los ntawm cov tshuaj tiv thaiv kab mob sulfur yog xim dub lossis xim liab, uas tuaj yeem ua rau cov tshuaj dawb hloov xim, yog li cov hlau lead ntsev stabilizer profile yog qhov ua rau muaj kuab lom. Cadmium stabilizers yog cov khoom muaj kuab lom. Yog tias siv hauv cov kav dej, lawv yuav ua rau yellowing ntawm cov kav dej hauv ib puag ncig sulfide, yog li cadmium stabilizers tsis tshua siv.
