Dab tsi yog PolyurethaneCuring Agent?
Hauv kev lag luam polyurethane, lo lus "kho tus neeg sawv cev" yog dav siv tab sis feem ntau to taub yuam kev. Cov chaw tsim khoom sib txawv, cov qauv tsim, thiab cov neeg siv kawg tuaj yeem siv tib lo lus los piav qhia cov khoom sib txawv. Yog li ntawd, tsis meej pem feem ntau tshwm sim thaum tham txog polyurethane systems.
Los ntawm kev pom zoo, txhua yam khoom siv uas pab cov khoom siv polyurethane kho thiab hloov los ntawm cov kua rau hauv cov khoom yuav raug hu ua tus neeg sawv cev kho. Txawm li cas los xij, los ntawm kev pom tshuaj lom neeg, cov lus txhais tau meej dua.
Ib tug polyurethane curing tus neeg sawv cev yog cov reactive Cheebtsam uas koom nyob rau hauv lub crosslinking cov tshuaj tiv thaiv thiab ua rau peb lub -siv polymer network lub luag hauj lwm rau qhov kawg mechanical zog ntawm cov khoom.
Kev nkag siab txog lub luag haujlwm ntawm cov tshuaj tua kab mob yuav tsum xub nkag siab tias polyurethane tsim li cas.
Yuav ua li cas polyurethane kho?
Polyurethane cov ntaub ntawv yog tsim los ntawm cov tshuaj tiv thaiv ntawm isocyanate pawg (-NCO) nrog cov nquag hydrogen- muaj cov tshuaj, feem ntau hydroxyl pawg (-OH) los yog amino pawg (-NH₂).
Thaum lub sij hawm no cov tshuaj tiv thaiv, ib tug neeg molecules ua chemically txuas ua ke, tsim ib tug polymer network. Cov txheej txheem no hloov cov khoom siv los ntawm cov kua lossis ib nrab -kua lub xeev mus rau hauv cov khoom elastomer, txheej, nplaum, ua npuas ncauj, los yog sealant.
Cov tshuaj tiv thaiv uas cuam tshuam nrog lub ntsiab resin thiab tsim lub network no feem ntau hu ua tus neeg sawv cev kho.
Thaum Isocyanates ua raws li tus neeg sawv cev kho?
Cov txheej txheem polyurethane feem ntau yog ob -cov txheej txheem polyurethane.
Hauv cov kab ke no:
Cheebtsam A muaj feem ntau ntawm polyether polyols lossis polyester polyols.
Cheebtsam B muaj isocyanates xws li MDI, TDI, HDI, lossis IPDI.
Cov khoom siv polyol ua haujlwm ua cov khoom qub, thaum cov khoom siv isocyanate reacts nrog hydroxyl pawg los tsim polyurethane linkages thiab crosslinks.
Nyob rau hauv no formulation, lub isocyanate tivthaiv yog suav hais tias yog tus neeg sawv cev kho.
Qhov no yog vim li cas nyob rau hauv polyurethane coatings, nplaum, cov ntaub ntawv hauv pem teb, thiab waterproofing tshuab, B tivthaiv yog feem ntau hu ua polyurethane curing agent los yog polyurethane hardener.
Thaum twg Polyols lossis Amines ua raws li tus neeg sawv cev kho?
Hauv qee lub tshuab polyurethane, qhov xwm txheej yog thim rov qab.
Ntau lub tshuab cam khwb cia polyurethane elastomer siv NCO-tawm polyurethane prepolymers ua cov khoom tseem ceeb. Cov prepolymers no twb muaj ntau tshaj isocyanate pawg thiab yog li ntawd yuav tsum tau cov tebchaw uas muaj cov nquag hydrogen kom ua tiav cov txheej txheem kho.
Lub prepolymer ua raws li lub hauv paus cob, thaum lub polyol los yog amine tivthaiv ua tus neeg sawv cev kho.
Piv txwv li, MOCA, DETDA, BDO, thiab lwm cov saw txuas ntxiv feem ntau hu ua cov tshuaj tua kab mob hauv cov cam khwb cia polyurethane elastomer vim tias lawv hnov mob nrog NCO- txiav tawm prepolymer thiab ua tiav cov kev sib txuas sib txuas.
Yog li, seb cov khoom puas raug suav hais tias yog tus neeg sawv cev kho yog nyob ntawm nws lub luag haujlwm hauv kev tsim es tsis yog nws tus kheej tshuaj.
Lwm qhov kev tsis meej pem yog qhov sib txawv ntawm cov tshuaj tua kab mob thiab cov catalysts.
Txawm hais tias ob qho tib si cuam tshuam cov txheej txheem kho, lawv cov haujlwm sib txawv kiag li.
Ib tug polyurethane curing tus neeg saib xyuas ncaj qha koom nrog cov tshuaj tiv thaiv thiab ua ib feem ntawm cov qauv polymer kawg. Nws txhawb nqa lub cev ntawm cov khoom tiav, suav nrog hardness, tensile zog, elongation, adhesion, tshuaj tsis kam, dej tsis kam, thiab kav ntev.
Ib qho polyurethane catalyst, los ntawm qhov sib txawv, tsis ua ib feem ntawm lub network polymer. Nws lub luag haujlwm tseem ceeb yog kom nrawm lossis tswj cov tshuaj tiv thaiv tus nqi.
Feem ntau polyurethane catalysts muaj xws li: Organotin catalysts, Bismuth catalysts, Tertiary amine catalysts, Hlau carboxylates
Catalysts feem ntau yog ntxiv ntawm qhov tsawg kawg nkaus thiab feem ntau cuam tshuam rau kev ua cov yam ntxwv xws li lub sijhawm gel, tack - lub sijhawm dawb, kho ceev, thiab lub lauj kaub lub neej.
Yog tsis muaj catalyst, polyurethane system tseem tuaj yeem kho, txawm tias qeeb dua.
Yog tias tsis muaj tus neeg sawv cev kho, cov tshuaj tiv thaiv polyurethane tsis tuaj yeem ua tiav, thiab cov khoom yuav nyob twj ywm kua lossis tsuas yog kho ib nrab xwb.
Qhov sib txawv tseem ceeb no qhia txog vim li cas cov tshuaj tua kab mob yog cov yam ntxwv ntawm cov polyurethane network, thaum cov catalysts ua cov khoom siv ntxiv.