Lub teeb pib

Lub teeb pib

Hauv cov txheej txheem photocurable, suav nrog UV kua nplaum, UV txheej, UV number case, thiab lwm yam, cov tshuaj hloov pauv tshwm sim tom qab tau txais lossis nqus lub zog sab nraud, thiab decompose rau hauv cov dawb radicals lossis cations, yog li ua rau cov tshuaj tiv thaiv polymerization.

Photoinitiators yog cov khoom uas tuaj yeem tsim cov dawb radicals thiab pib ua polymerization ntxiv los ntawm illumination.Tom qab qee cov monomers illuminated, lawv nqus photons thiab tsim lub xeev zoo siab M * : M + HV → M *;

Tom qab homolysis ntawm activated molecule, lub dawb radical M * → R· + R '· yog generated, thiab ces lub monomer polymerization yog pib los tsim cov polymer.

Radiation curing thev naus laus zis yog lub zog txuag hluav taws xob tshiab thiab kev tiv thaiv ib puag ncig, uas yog irradiated los ntawm ultraviolet light (UV), electron beam (EB), infrared teeb, pom lub teeb, laser, tshuaj fluorescence, thiab lwm yam, thiab tag nrho raws li "5E" Cov yam ntxwv: Ua tau zoo, Ua kom muaj txiaj ntsig, txuag hluav taws xob, thiab ib puag ncig tus phooj ywg. Yog li ntawd, nws yog hu ua "Green Technology".

Photoinitiator yog ib qho tseem ceeb ntawm photocurable adhesives, uas plays lub luag hauj lwm txiav txim siab nyob rau hauv curing npaum li cas.

Thaum lub photoinitiator yog irradiated los ntawm ultraviolet lub teeb, nws absorbs lub zog ntawm lub teeb thiab splits mus rau hauv ob active dawb radicals, uas pib cov saw polymerization ntawm photosensitive resin thiab lub active diluent, ua rau cov nplaum cross-linked thiab solidified. Lub photoinitiator muaj cov yam ntxwv ntawm kev ceev ceev, kev tiv thaiv ib puag ncig thiab txuag hluav taws xob.

Tus thawj molecules tuaj yeem nqus lub teeb hauv thaj tsam ultraviolet (250 ~ 400 nm) lossis pom thaj tsam (400 ~ 800 nm). Tom qab absorbing lub teeb lub zog ncaj qha los yog tsis ncaj, tus pib molecules hloov ntawm lub xeev hauv av mus rau lub xeev siab singlet, thiab tom qab ntawd mus rau lub xeev zoo siab triplet los ntawm kev hloov pauv.

Tom qab lub singlet los yog triplet xeev zoo siab los ntawm monomolecular los yog bimolecular tshuaj cov tshuaj tiv thaiv, cov active fragments uas yuav pib monomer polymerization yuav dawb radicals, cations, anions, thiab lwm yam.

Raws li cov txheej txheem pib sib txawv, photoinitiators tuaj yeem muab faib ua dawb radical polymerization photoinitiator thiab cationic photoinitiator, ntawm cov dawb radical polymerization photoinitiator yog siv dav tshaj plaws.