Yellowing ntsiab ntawm daim txhuam cev
Kev tsom xam ntawm cov tub ntxhais tseem cuam tshuam rau kev yellowing ntawm polyurethane daim txhuam cev
Kev yelling ntawm polyurethane so ua npuas dej tau ntev tau sib tw rau ob qho tib si ua npuas ncauj thiab cov khoom siv polyol. Ntau tus neeg tsim khoom ua npuas dej, tshwj xeeb yog cov tshwj xeeb hauv kev ua npuas dej, tau sim txhim kho cov tshuaj tiv thaiv kab mob, tab sis cov txiaj ntsig kev txhim kho kom tau zoo dua qub tau txais kev tsis txaus siab.
Feem ntau, los ntawm qhov kev pom ntawm cov kev sib ntxiv, kev cog qoob loo ntawm daim txhuam cev suav nrog plaub hom hauv qab no:
Plaub hom loj ntawm yellowing thiab lawv cov tshuab
1. Thermal oxidative yellowing
Cause: Thaum tsim kev ua npuas ncauj (cov tshuaj tiv thaiv txias tuaj yeem tshaj 100 degree), xws li kev ua kom kub (xws li tsim cov roj ntsha (xws li tsim cov qauv kub (piv txwv li cov qauv oxiDethen (piv txwv li cov qauv kub (piv txwv li, quinone qauv) uas ua rau daj.
Kev suav ntxiv: Qhov no yog cov tshuaj tiv thaiv kab mob tiv thaiv ua si lub luag haujlwm zoo los ntawm kev cuam tshuam oxidative cajd cov tshuaj tiv thaiv los tiv thaiv kev ua kom tsis txhob muaj kev tawm tsam.
2. Gas fum gelling
Cause: Thaum daim txhuam cev raug rau cov pa uas muaj cov pa roj ntsha (NOx, feem ntau yog {} l}
Kev tawm tsam: Zam lossis txo cov tshuaj amine uas tau yooj yim hnov mob nrog NOEx.
3. Ntaub npog staining
Cause: Qee yam cov tshuaj molecular me me (feem ntau yog cov kab mob volatile) nyob rau hauv daim txhuam cev mided rau kev sib chwv nrog nws (xws li cov kab txaij thiab daim ntaub plaub hau ntawm cov ntaub.
Thawj Qhov: Cov ntaub ntawv qhia meej qhia tias antioxidant BHT yog lub ntsiab ua rau cov ntaub npuag. BHT nws tus kheej tuaj yeem oxidize los tsim cov tshuaj daj, thiab nws cov kev sib cav sib koom ua ke tsiv teb tsaws rau cov ntaub saum npoo.
4. UV kev sib daj sib deev
Cause: qee yam qauv nyob rau hauv Polyurethane molecular charets (xws li cov neeg kho siab tshaj plaws (TDI) yauv ua lub teeb ci ntsa iab hauv qab.
Kev suav ntxiv: Ntxiv cov teeb ruaj ruaj (xws li UV nqus lossis cuam tshuam cov amine teeb citilivizizers) yog qhov mus dhau qhov muaj peev xwm ntawm cov tshuaj tiv thaiv kab mob antioxidants zoo.
Cov tub ntxhais kev tsis sib haum: lub "ob lub luag haujlwm" ntawm Antioxidants
Cov nyhuv zoo: tiv thaiv cov thermal oxidative yellowing thaum ua. Yog tsis muaj cov tshuaj antioxidants, tus txhuam hniav yuav ua rau pom thiab daj thaum tsim khoom. Qhov no yog qhov tseem ceeb vim li cas vim li cas polyol tuam ntxhab yuav tsum ntxiv tshuaj tua kab mob tshuaj tua kab mob.
Cov teebmeem tsis zoo: Qee cov antioxidants lawv tus ua "catalysts" lossis "reactants" rau lwm hom daj.
Amine -} based antioxidants: Thaum ua tau zoo tiv thaiv cov pa roj oxidation, lawv tau ua cov roj daj daj ntsuab thiab teeb {1} - ua rau yellowing.
BHT -} Raws antioxidants: txawm hais tias tsawg- tus nqi, lawv yog thawj tus nqi, lawv yog thawj tus neeg ua txhaum tom qab npuag staining.
Hauv paus ua rau thiab daws cov lus qhia
Cov chaw tsim tshuaj ua npuas ncauj feem ntau saib cov khoom cuam tshuam zoo tshaj plaws ntawm lub tshuab hluav taws xob presetekas hauv cov dej daj cua dub ntawm cov khoom cog qoob loo ntawm cov khoom kawg.
Kev daws cov lus qhia:
Pib nrog raw khoom (polyol) xaiv:
Nug nrog polyol cov chaw muag khoom txog cov tshuab tshuaj antioxidant lawv siv. Txog siab -}}} Cov tshuab ua kom muaj zog, ua kom muaj zog}}} bht thiab tsis {} Am6 6} Am6.
Niaj hnub nimno siab - Kev Ua Haujlwm Antioxidants Thaum zam BHT cov teeb meem tsis ruaj khov
Txhim kho cov qauv thiab kev ua haujlwm:
Ua tib zoo xav txog post -}}}} · stabilizant system yog feem ntau tsis muaj peev xwm,
Xav txog hom ntawm isocyanate siv: rau cov khoom lag luam sab nraum zoov uas yuav tsum tau ua kom zoo nkauj oocyanates (piv txwv li, HDI) raws li lub hauv paus rau Polyurethane. Lawv txoj kev yellowing yog farior zoo tshaj plaws uas siv aromatic isocyanates (TDI / MDI), txawm hais tias ntawm tus nqi siab dua.
Hauv cov ntsiab lus xaus, daws qhov teeb meem daj tsis tuaj yeem cia siab rau "kev ntsuas" kev sib ntxiv thaum ua npuas ncauj. Hloov chaw, nws yuav tsum tau tshuaj xyuas txoj kev kuaj xyuas tag nrho ntawm tag nrho cov khoom siv muab cov khoom siv los ntawm kev pom ntawm cov ntaub ntawv kev tshawb fawb. Xaiv cov polyols nrog cov tshuab tshuaj tiv thaiv kab mob uas phim rau cov khoom yaig
