Thaum khawb cov yeeb nkab rwb thaiv tsev uas tau ua haujlwm rau tsib lossis rau xyoo, tej zaum koj yuav pom cov xwm txheej zoo li no: polyurethane ua npuas ncauj yog blackened, crumbles yooj yim thaum nyem, thiab txawm tias dej xau. Ntau tus neeg thawj cov tshuaj tiv thaiv yog "dej ingress" los yog "aging," tab sis raws li kev soj ntsuam ze, lub hauv paus ntawm qhov teeb meem feem ntau nyob rau hauv ib tug inconspicuous qhia- kaw - cell ratio.
Qhov kaw - cell ratio yog ib qho ntawm cov tseem ceeb tsis zoo rau kev ntsuas qhov zoo ntawm polyurethane ua npuas ncauj. Qhov zoo tshaj plaws, polyurethane ua npuas ncauj yuav tsum muaj ntau tus neeg ywj pheej, kaw -cov npuas cua ntawm tes, txhua qhov muaj cov pa roj foaming nrog cov thermal conductivity tsawg, thiab cov npuas no tsis muaj kev sib txuas. Cov qauv no muaj txiaj ntsig zoo thaiv cov hluav taws xob hluav taws xob thiab ua raws li qhov thaiv nruj kom tiv thaiv kev nkag mus ntawm noo noo. Raws li GB/T 29047, kaw - cell ratio ntawm polyurethane ua npuas ncauj siv rau ncaj qha - faus rwb thaiv tsev kav yuav tsum tsis pub tsawg tshaj 88%. Yog tias tus nqi no tsis tau raws li, qhov tshwm sim muaj ntau heev.
Ua ntej, cov nyhuv rwb thaiv tsev yog cuam tshuam. Hauv ua npuas ncauj nrog qhov qis kaw- ntawm tes piv, ntau lub hlwb nyob rau hauv ib qho kev sib txuas, tso cai rau cov pa npuas sab hauv kom yooj yim khiav, thaum huab cua sab nraud tuaj yeem nkag mus thiab tawm. Thaum tshav kub kub convection thiab hluav taws xob nce, ua rau muaj kev nce siab hauv thermal conductivity. Rau tib lub yeeb nkab txoj kab uas hla thiab rwb thaiv tsev thickness, cov kav dej uas tsis txaus kaw - xov tooj ntawm tes muaj kev kub ntxhov ntau dua piv rau cov uas muaj rwb thaiv tsev txaus. Thaum tshav kub kub poob thaum thauj, yuam cov tuam txhab cua sov kom hlawv roj ntau dua kom them, tus nqi tsim nyog rau cov nqi khiav haujlwm txhua hnub.
Txawm tias muaj teeb meem ntau dua li kev poob cua sov yog dej nqus. Cov kav dej faus yog tas li raug rau cov av ntub dej. Txawm tias tsis muaj kev puas tsuaj rau sab nrauv, noo noo tuaj yeem nkag mus rau hauv txheej txheej rwb thaiv tsev los ntawm qhov khoob me me. Thaum ua npuas ncauj nrog txaus kaw- cell ratios zoo tiv thaiv kom tsis txhob ya raws, thaum lub pores ua interconnected, dej yog absorbed rau hauv lub npuas zoo li daim txhuam cev. Dej lub thermal conductivity yog ntau tshaj nees nkaum zaug siab tshaj ntawm cov cua tseem, ua rau ib tug precipitous poob nyob rau hauv lub npuas lub rwb thaiv tsev kev ua tau zoo tom qab nqus noo noo. Ntxiv rau, cov dej ntim tau tuaj yeem hydrolyze cov polyurethane, ua rau cov npuas dej soften, acidify, thiab thaum kawg hmoov, thaum kawg poob nws lub zog. Nyob rau theem no, tag nrho cov kav dej yuav tsum tau khawb thiab hloov, nrog rau cov nqi kho kom deb tshaj qhov kev txuag cov khoom siv thawj zaug.
Lwm yooj yim overlooked lub txim yog accelerated aging. Ua npuas ncauj nrog qis kaw- cell ratio tau txo qis kev tiv thaiv tshav kub. Nyob rau hauv lub sij hawm ntev - lub sij hawm siab - kub ua hauj lwm ntawm cov kav dej cua sov, cov polymer chains nyob rau hauv ua npuas ncauj yog feem ntau yuav tawg, ua rau cov xim hloov los ntawm daj mus rau dub, thiab lub compressive zog poob sai heev. Cov kav dej qub tsim los rau lub neej 30 xyoo tuaj yeem ntsib cov txheej txheem rwb thaiv tsev tawg thiab raug cov kav hlau tsis pub dhau kaum xyoo.
Yog li ntawd, qhov kaw - cell ratio yog ib qho tseem ceeb heev uas yuav tsum tau xav txog thaum yuav cov kav dej rwb thaiv tsev. Qhov sib txawv ntawm tsuas yog ob peb feem pua ntawm cov ntsiab lus hauv qhov thib peb- tsab ntawv tshaj tawm kev sim ntawm tog neeg feem ntau txiav txim siab seb cov kav dej puas yuav ua haujlwm ruaj khov tom qab tsib xyoos lossis yuav tsum tau kho thiab hloov pauv loj.