Tam sim no, muaj ntau ntau hom ntawm ib leeg-tiv thaiv elastic sealants ntawm kev ua lag luam, feem ntau yog silicone thiab polyurethane sealant khoom.Ntau hom elastic sealants muaj qhov sib txawv hauv lawv cov pab pawg ua haujlwm zoo thiab kho cov saw hlau tseem ceeb.Raws li qhov tshwm sim, muaj ntau lossis tsawg dua kev txwv hauv nws cov khoom siv thiab thaj chaw.Ntawm no, peb qhia txog kev kho cov txheej txheem ntawm ntau qhov sib xyaw ua ke reactive elastic sealants thiab sib piv qhov zoo thiab qhov tsis zoo ntawm ntau hom elastic sealants, thiaj li ua rau peb nkag siab tob thiab xaiv qhov tsim nyog hauv kev siv tswv yim.
1. Hom ib-tivthaiv reactive elastic sealant curing mechanism
Feem ntau ib feem ntawm reactive elastic sealants feem ntau suav nrog: silicone (SR), polyurethane (PU), silyl-terminated modified polyurethane (SPU), silyl-terminated polyether (MS), Cov prepolymer muaj ntau pawg ua haujlwm sib txawv thiab sib txawv kho cov tshuaj tiv thaiv.
1.1Kho mechanism ntawm silicone elastomer sealant
Daim duab 1. Kho mechanism ntawm silicone sealant
Thaum siv silicone sealants, lub prepolymer reacts nrog cov kab ntawm noo noo nyob rau hauv cov huab cua thiab ces solidifies los yog vulcanizes nyob rau hauv qhov kev txiav txim ntawm ib tug catalyst.Cov by-products yog me me molecular tshuaj.Cov txheej txheem muaj nyob rau hauv daim duab 1. Raws li qhov sib txawv me me molecular tshuaj tso tawm thaum kho, silicone sealant kuj muab faib ua deacidification hom, deketoxime hom, thiab dealcoholization hom.Qhov zoo thiab qhov tsis zoo ntawm cov hom silicone kua nplaum no tau sau tseg hauv Table 1.
Table 1.Kev sib piv ntawm qhov zoo thiab qhov tsis zoo ntawm ntau hom silicone nplaum
1.2 Kho mechanism ntawm polyurethane elastic sealant
Ib qho khoom siv polyurethane sealant (PU) yog ib hom polymer uas muaj cov urethane rov ua ntu (-NHCOO-) hauv cov saw tseem ceeb ntawm cov molecule.Cov txheej txheem kho yog tias isocyanate reacts nrog dej los tsim ib qho tsis ruaj khov nruab nrab carbamate, uas tom qab ntawd sai sai decomposes los tsim CO2 thiab amine, thiab tom qab ntawd cov amine reacts nrog ntau tshaj isocyanate hauv lub cev, thiab thaum kawg tsim ib qho elastomer nrog lub network qauv.Nws curing cov tshuaj tiv thaiv yog raws li nram no:
Daim duab 1.Curing cov tshuaj tiv thaiv mechanism ntawm polyurethane sealant
1.3 Curing mechanism ntawm silane-hloov polyurethane sealant
Daim duab 3. Kho cov tshuaj tiv thaiv mechanism ntawm silane-hloov polyurethane sealant
Raws li kev pom ntawm qee qhov tsis txaus ntawm polyurethane sealants, polyurethane tsis ntev los no tau hloov kho los ntawm silane los npaj cov nplaum, tsim ib hom tshiab sealing nplaum nrog cov saw tseem ceeb ntawm polyurethane qauv thiab ib pawg alkoxysilane kawg, hu ua silane-modified polyurethane sealant (SPU).Kev kho cov tshuaj tiv thaiv ntawm hom sealant no zoo ib yam li cov silicone, uas yog, cov pab pawg alkoxy hnov mob nrog dej kom dhau mus rau hydrolysis thiab polycondensation los ua kom ruaj khov Si-O-Si peb-dimensional network qauv (Daim duab 3).Lub network cross-linking cov ntsiab lus thiab nruab nrab ntawm qhov sib txuas cov ntsiab lus yog polyurethane hloov tau raws ntu qauv.
1.4 Kho mechanism ntawm silyl-terminated polyether sealants
silyl-terminated polyether sealant (MS) yog ib qho khoom siv elastic nplaum raws li kev hloov kho silane.Nws muab cov txiaj ntsig zoo ntawm ob qho tib si polyurethane thiab silicone, yog lub cim tshiab ntawm cov khoom siv nplaum nplaum, tsis muaj PVC, silicone roj, isocyanate thiab hnyav.MS adhesive reacts nrog cov dej noo nyob rau hauv cov huab cua ntawm chav tsev kub, yog li ntawd cov silanized polymer nrog -Si (OR) LOSSIS -SIR (OR) - qauv yog hydrolyzed ntawm cov saw kawg thiab cross-linked rau hauv ib tug elastomer nrog Si-O- Si network qauv kom ua tiav sealing thiab bonding nyhuv.Cov txheej txheem curing yog raws li nram no:
Daim duab 4. Kho mechanism ntawm silyl-terminated polyether sealant
2. Kev sib piv ntawm qhov zoo thiab qhov tsis zoo ntawm cov khoom siv ib leeg reactive elastic sealants
2.1 Qhov zoo thiab qhov tsis zoo ntawm silicone sealants
⑴ Qhov zoo ntawm silicone sealant:
① Cov huab cua zoo heev, tiv thaiv oxygen, tiv thaiv ozone thiab ultraviolet tsis kam;② Qhov kub thiab txias hloov tau zoo.
⑵ Disadvantages ntawm silicone sealant:
① Kev kho kom zoo nkauj tsis zoo thiab tsis tuaj yeem pleev xim;② Lub zog tsim kua muag tsawg;③ Cov roj tsis txaus;④ Tsis puncture-resistant;⑤ Cov nplaum nplaum yooj yim tsim cov roj ntsha uas muaj paug rau cov pob zeb, pob zeb thiab lwm yam xoob substrates.
2.2 Qhov zoo thiab qhov tsis zoo ntawm Polyurethane Sealants
⑴ Qhov zoo ntawm polyurethane sealant:
① Zoo adhesion rau ntau yam substrates;② Kev ua haujlwm zoo ntawm qhov kub thiab txias;③ Zoo elasticity thiab zoo heev rov qab zog, haum rau dynamic pob qij txha;④ Lub zog txhua yam muaj zog, zoo heev hnav tsis kam, roj tsis kam thiab kev laus ua haujlwm;⑤ Feem ntau cov khoom siv dej-kho polyurethane sealants yog hnyav-dawb thiab tsis muaj kuab paug rau substrate thiab ib puag ncig;⑥ Qhov saum npoo ntawm lub sealant tuaj yeem pleev xim thiab siv tau yooj yim.
⑵ Qhov tsis zoo ntawm polyurethane sealant:
① Thaum kho hauv qhov kub thiab txias ib puag ncig ntawm qhov nrawm nrawm, npuas tau yooj yim tsim, uas cuam tshuam rau kev ua haujlwm ntawm sealant;② Thaum sib txuas thiab sib khi cov khoom ntawm cov khoom tsis muaj qhov ntxeem tau (xws li iav, hlau, thiab lwm yam), feem ntau yuav tsum muaj primer;③ Plua plav Cov xim xim muaj qhov cuam tshuam rau UV kev laus, thiab qhov ruaj khov ntawm cov kua nplaum yog cuam tshuam zoo heev los ntawm kev ntim khoom thiab lwm yam kev mob;④ Lub tshav kub tsis kam thiab kev laus tsis kam yog me ntsis tsis txaus.
2.3 Qhov zoo thiab qhov tsis zoo ntawm silane-hloov polyurethane sealants
⑴ Qhov zoo ntawm silane hloov polyurethane sealant:
① Curing tsis tsim npuas;② Muaj qhov yooj yooj yim, hydrolysis tsis kam thiab tshuaj lom neeg ruaj khov;③ Cov huab cua zoo heev, tiv thaiv tshav kub, tiv thaiv kev laus, khoom ruaj khov;④ Kev hloov pauv dav dav rau cov substrates, thaum sib txuas Feem ntau, tsis tas yuav tsum muaj primer;⑤ Cov nplaim tuaj yeem pleev xim.
⑵ Disadvantages ntawm silane hloov polyurethane sealant:
① UV tiv thaiv tsis zoo li silicone sealant;② Lub kua muag tsis kam yog me ntsis phem dua li ntawm polyurethane sealant.
2.4 Qhov zoo thiab qhov tsis zoo ntawm silyl-terminated polyether sealants
⑴ Qhov zoo ntawm silyl-terminated polyether sealant:
① Nws muaj cov khoom sib txuas zoo heev rau feem ntau cov substrates thiab tuaj yeem ua tiav kev sib txuas ua haujlwm tsis muaj primer;② Nws muaj kev tiv thaiv tshav kub zoo dua thiab UV kev laus ua haujlwm zoo dua li qub polyurethane;③ Nws tuaj yeem pleev xim rau ntawm nws qhov chaw.
⑵ Qhov tsis zoo ntawm silyl-terminated polyether sealant:
① Cov huab cua tiv thaiv tsis zoo li cov silicone silicone, thiab cov kab nrib pleb tshwm rau saum npoo tom qab kev laus;② Lub adhesion rau iav tsis zoo.
Los ntawm cov lus qhia saum toj no, peb muaj kev nkag siab ua ntej ntawm kev kho cov txheej txheem ntawm ntau hom kev siv ib leeg-tiv thaiv elastic sealants, thiab los ntawm kev sib piv lawv qhov zoo thiab qhov tsis zoo, peb tuaj yeem ua tiav kev nkag siab tag nrho ntawm txhua yam khoom.Hauv kev siv cov tswv yim, cov sealant tuaj yeem xaiv tau raws li qhov kev thov tiag tiag ntawm qhov sib txuas kom ua tiav zoo sealing lossis kev sib txuas ntawm daim ntawv thov.
Post lub sij hawm: Nov-15-2023