Vim li cas Polyurethane ua npuas dej tig daj?
POLYURETHANE (PU) Ua npuas ncauj yog dav siv nyob rau hauv rooj tog, kev pam vov, ntim khoom, thiab lwm yam kev siv rau nws cov versatility thiab Cushioning Khoom.
Txawm li cas los xij, daj ntawm pu npuas lub sij hawm yog qhov teeb meem ib txwm muaj cuam tshuam rau kev ua kom loog thiab seb yuav txhawj xeeb txog cov khoom tsis txheeb. Qhov tshwm sim tshwm sim los ntawm cov tshuaj lom neeg thiab ib puag ncig ib puag ncig. Hauv qab no yog cov ncauj lus kom ntxaws tshuaj xyuas ntawm cov laj thawj thiab cov kev daws teeb meem rau pu npuas daj.
I. Qhov tseem ceeb ua rau daj
1. Daim duab-oxidation (UV-ua rau kev ua tsis yog)
Lub tshuab:
PU foam muaj cov pab pawg neeg tshuaj xws li cov pab pawg ua haujlwm (-Thib-) thiab ete excages (-) uas yog rhiab rau ultraviolet (UV) lub teeb. Thaum raug rau UV hluav taws xob (290-400 nm wavelengths), cov sib khi no, ua rau muaj kev ywj pheej dawb. Cov radicals ua rau cov kev sib tw uas ua rau cov qauv sib tw (cov xim muaj xim ntxiv), xws li ob npaug quinoid sib txuas, uas tau nqus lub teeb thiab tshwm xim daj.
Nraws cov khoom siv:
Lub hnub ncaj qha, teeb pom kev zoo fluorescent, lossis ib puag ncig nrog UV kis tau cov txheej txheem no ua kom nrawm dua cov txheej txheem no. Qhib-cell ua npuas ncauj, nrog thaj chaw loj dua, muaj ntau dua kev daj ntseg daj dua kaw-cell ua npuas.
2. Thermal oxidation
Thaum Tshav Kub Kub No:
At elevated temperatures (>60 degree), lub zog ntawm cov roj polymer nce, pub cov pa oxygen kom nkag mus rau cov khoom yooj yim dua. Qhov no ua rau oxidation, ua cov pab pawg carbonyL (c =}} awbb xiav lub teeb thiab muaj kev sib daj sib luag.
Sab hauv kev sib txhuam:
Rov ua dua compression ntawm npuas dej (piv txwv li, hauv cov txaj pw) tsim cov cua sov hauv zos, txhawb kev txhawb nqa thiab daj.
3. Kev tsiv teb tsaws chaw thiab kev tawm tsam
Catalyst tseem tshuav:
Amine-based catalysts (piv txwv li, trietylenediamine) siv nyob rau hauv pu synthesis yuav nyob tsis tau. Cov seem no tuaj yeem hnov mob nrog nitrogen oxides (NOx) hauv huab cua, sib sau cov xim daj nitroamine compound.
Nplaim taws retardants:
Halogenated lossis phosphorus-raws cov nplaim hluavtaws tuaj yeem ua rau ncua sijhawm, tso acidic los ntawm catymer charmess thiab disoloration.
Antioxidant depletion:
Antioxidants nyiam butylated hydroxytoluene (BHT) AVEEL AUTELETE, txo lub npaus lub peev xwm tiv thaiv oxidation.
4. Ib lub chaw tsis muaj zog
Cov pa paug pa:
Nitrogen oxides (NOX) thiab ozone (o₃) hnov nrog amine pawg nyob rau hauv PU, sib sau ua yeeb yaj kiab daj.
Hlau Ion Catalysis:
LWAC METAL (piv txwv li, tooj liab, tooj liab) los ntawm kev tuav lossis cov khoom ntim khoom tuaj yeem ua raws li catalysts, nrawm oxidation.
Ii. Cov tswv yim los ua kev sib tsoo daj
1. Molecular tsim kev txhim kho
Siv aliphatic isocyanates:
Hloov cov ntxhiab isocyanates (piv txwv li, mdi, tdi) nrog cov kev xaiv aliphatic zoo li Hexamethylene Diisocyanate (HDI), uas tsis muaj UV-nkag siab daj.
Teeb tsa pab pawg ruaj khov:
Hloov polyols nrog ua kom UV Stabilizers, xws li tabkov amine teeb cigilizers (hales) lossis benzotriazole derivatives, txhawm rau txhim kho kev cuam tshuam.
2. Additive Tshuab
UV nqus:
Ntxiv nrog UV {-326}}}}}}}}}}}}}}}}} absor absor absor absor absor absor rad rad u from from from from from from from from Decadation.
Synergistic antioxidants:
Muab cov yeeb yaj kiab tseem ceeb (piv txwv li, cov kab mob phoschaw) nrog cov tshuaj tiv thaiv theem nrab (piv txwv li phosphites) kom cuam tshuam oxidation saw kev sib tw.
Lub teeb txhab:
Yog vim tias scavenge dawb radicals, rhuav qhov kev ua tsis taus pa. Lawv ua haujlwm Synergistically nrog UV nqus rau kev tiv thaiv zoo dua.
3. Cov txheej txheem optimization
Tom Qab Kho:
Ncua lub sijhawm kho kom meej kom paub meej cov kev siv ua tiav ntawm cov khoom seem, txo cov ntsiab lus amine.
Cov Khaub Ncaws Tiv Thaiv:
Thov siv cov txheej txheem UV-resistant (piv txwv li, silicone lossis polyurethane zaj duab xis) los tsim cov kev thaiv kev oxygen thiab cov pa paug.
4. Ib puag ncig tswj hwm
UV Shielding:
Siv UV-thaiv kev ntim khoom lossis cov quav ntxiv zoo li cov carbon dub kom txwv lub teeb kis thaum lub sijhawm khaws cia.
Kev Nyab Xeeb Tswjhwm:
Khw ua npuas ncauj rau hauv txias (<30°C), dry (RH <50%) environments to slow oxidative reactions.
III. Kev Lag Luam Kev Lag Luam thiab Cov Qauv
Nrov Cov Laus Kev Ntsuas:
QUV sim: Simulates UV raug siv ASTM G154 los kwv yees kev ya mus ntev.
Xenon Arc Kuaj: Ua raws li iso 4892-2} kom cov kev cuam tshuam puv ntoob tshav ntuj.
Kev ntsuas xim:
Spectrophhottometers qua qhov xim hloov ntawm Δe qhov tseem ceeb; ΔE 2 qhia tau yellowing.
Kev Kawm Txog:
Dow tshuaj lub voranol ™ polyols, optimized rau UV kuj, tuaj yeem txuas ua npuas service lub neej los ntawm 3-5 × hauv cov kev pabcuam hauv tsheb.
IV. Tag
Yellowing hauvPU npausQhov tshwm sim los ntawm kev sib xyaw ntawm UV kis, cua sov, oxidation, kev sib txuas lus ntxiv, thiab ib puag ncig cov pa paug. Cov kev daws teeb meem niaj hnub no tsom rau cov khoom siv rov qab (piv txwv li, aliphatic isocyanates), advi privilizers, thiab kev tswj hwm cov txheej txheem tshiab. Ua ke inserently ruaj polymers nrog kev tiv thaiv cov ntaub ntawv tiv thaiv zoo li cov rooj zaum cov khoom lag luam zoo nkauj tuaj yeem ua tiav cov xim ntev ntev.
Cov neeg tsim khoom lag luam yuav tsum muaj nqi nqi thiab ua tau zoo rau kev siv cov kev siv rau kev siv tshwj xeeb. Kev tshuaj xyuas ib txwm ua dhau los ntawm kev soj ntsuam nrawm ua raws li cov qauv kev lag luam thiab cov neeg siv khoom ntiag tug.