1 Xaiv cov roj hmab nyoos
Phaj kub exchanger roj hmab gasket tib lub sij hawm los ntawm cov roj sab ntawm qhov kub thiab txias, dej sab ntawm lub luag hauj lwm ntawm kev kub siab, thiab kuj muaj kev sib cuag nrog huab cua, cov kev ua hauj lwm tej yam kev mob xav tau ntau dua. Yog li ntawd, cov khoom yuav tsum zoo heev tshav kub compression kuj, thiab muaj peev xwm tiv taus qhov nruab nrab ntawm dej thiab nws chav. Hauv cov xwm txheej zoo li no, yuav tsum xaiv propylene pawg feem ntawm 40% ~ 50% ntawm EPDM, vim tias hom EPDM elasticity no yog qhov zoo tshaj plaws.
EPDM nrog ntau pawg ntawm peb monomer muaj elasticity zoo thiab tsis tshua muaj compression teeb; Txawm li cas los xij, vim qhov siab ntawm kev sib txuas sib txuas, lub zog tensile thiab elongation ntawm kev tawg yog qis dua, thiab kev laus kuj tseem tsis zoo. Tsis tas li ntawd, kev laus tsis kam ntawm EPDM nrog ENB raws li qhov thib peb monomer zoo dua li ntawm EPDM nrog HD.
2 Kho qhov system
Feem ntau, EPDM roj hmab tuaj yeem ua vulcanized nrog ob hom vulcanization tshuab: peroxide thiab sulfur daj vulcanization. Qhov sib txuas sib txuas cov qauv ntawm peroxide vulcanization system yog CC daim ntawv cog lus, thaum lub caij sib txuas cov qauv ntawm cov sulfur vulcanization system yog CS daim ntawv cog lus. CC daim ntawv cog lus yog ntau thermally ruaj khov tshaj li CS daim ntawv cog lus, yog li kub resistant EPDM roj hmab yog vulcanized nrog peroxide. Feem ntau siv peroxide yog DCP. Nrog rau qhov nce ntawm DCP ntau npaum, cov roj hmab vulcanized yog maj hloov los ntawm thawj zaug undersulfurization, tsis tshua muaj zog thiab loj deformation mus rau qhov nce ntawm lub zog thiab txo deformation; ces qhov degree ntawm vulcanization yog ntxiv, lub zog pib poob, thiab deformation mus txog qhov tsawg kawg nkaus; Thaum kawg, tom qab qhov dhau ntawm vulcanizing tus neeg sawv cev, ib feem ntawm cov saw hlau molecular pib tawg cov saw degradation, lub zog tseem poob qis, thiab qhov deformation yog maj mam nce.
3. Cov kua nplaum
EPDM belongs rau cov roj hmab uas tsis yog-crystalline, cov roj hmab nyoos tsis siab. Tab sis tom qab ntxiv cov khoom siv ntxiv dag zog, lub zog tau nce ntau. Kev txhawb nqa cov khoom siv feem ntau tsis tshua muaj kev cuam tshuam rau kev tiv thaiv tshav kub, tab sis ua kom cov khoom ntim ntxiv tseem pab txhim kho cov cua sov ntawm cov roj hmab, tab sis kuj txo cov nqi.
Raws li qib ntawm carbon dub nce, cov txheej txheem compression txo qis, elasticity nce, thiab lub zog txo. Lub zog ntawm N990 carbon dub yog tsawg dhau thiab nyuaj rau kev tswj hauv kev tsim khoom, yog li nws tsis siv. Los ntawm xaiv N762 carbon dub, tus nqi qis compression tuaj yeem tau txais. Txhawm rau pab txhawb kev tawg ntawm cov pa roj carbon dub thiab tau txais kev ua haujlwm zoo, xaiv ib qho me me ntawm plasticizer paraffin roj, uas yog sib xws nrog ethylene propylene roj hmab.
4. Crosslinking tus neeg saib xyuas
Tsis muaj qhov tsis txaus ntseeg ntawm cov saw tseem ceeb ntawm EPDM, txawm hais tias peroxide vulcanization tuaj yeem siv tau, tab sis qhov ceev ntawm vulcanization qeeb, crosslinking efficiency tsawg. Txhawm rau kom ruaj khov thiab ceev cov txheej txheem vulcanization, nws yog ib qho tsim nyog yuav tsum siv tus neeg sawv cev crosslinking. TAC / GR kho tau zoo dua rau kev tawg thiab hnyav.
Nrog rau qhov nce ntawm TAC / GR, lub zog tensile, elongation ntawm kev tawg thiab compression mus tas li deformation ntawm vulcanized roj hmab txo, thiab MH tus nqi ntawm qhov tensile kev nyuaj siab tau nce. Nws tuaj yeem pom tias crosslinking ceev ntawm vulcanized roj hmab tau txhim kho, cov khoom siv kho tshuab txo qis, tab sis qhov elasticity tau loj dua. Nyob rau tib lub sijhawm, tus nqi ML poob qis, qhia tias Mooney viscosity poob qis, fluidity ntawm cov roj hmab tau txhim kho, thiab nws yooj yim rau kev ua tiav; ts1 yeej tsis hloov pauv, thiab tus nqi t 90 tau luv luv, thiab qhov ceev ntawm vulcanization tau pom tseeb. Kev laus kev ua haujlwm tsis zoo ntawm 1.5phr ntawm TAC / GR. Qhov no yuav yog vim muaj kev sib txuas ntawm kev sib txuas, qhib cov txheej txheem peroxide vulcanization, txo lub sijhawm vulcanization, txo qhov muaj peev xwm ntawm cov roj hmab molecular saw tawg thiab disproportionation ntawm qhov kub thiab txias. Thaum cov nyiaj ntau dhau, nws txhim kho qhov kev laus ntawm kev sib txuas ntawm cov roj hmab thiab txo cov cua sov ntawm EPDM. Tom qab sib piv, compression mus tas li deformation yog qhov zoo dua ntawm 2phr, thiab qhov kub tsis kam yog tsis txi ntau, yog li TAC / GR yog siv ntawm 2phr.
5.Antioxidant
EPDM tuaj yeem siv tau ntev ntawm 150 ℃ , tab sis dhau 150 ℃ , cov molecules pib muaj hnub nyoog maj mam, thiab ntawm 180 ℃ , cov roj hmab molecular saw yuav maj mam decompose. Txhawm rau txhim kho nws cov kev ua tau zoo ntawm qhov kub thiab txias, cov tshuaj tiv thaiv yuav tsum tau siv. Nyob rau hauv cov ntaub ntawv ntawm dej-vapor media, cov tshuaj tua kab mob RD tuaj yeem siv tau, uas tiv taus qhov kub thiab txias tab sis tsis yooj yim cuam tshuam rau vulcanization. Tsis tas li ntawd, 0.5phr antioxidant D tuaj yeem siv los ua kom muaj peev xwm tiv taus cov pa oxygen hauv huab cua thiab txhim kho cov flexural qaug zog tiv thaiv. Qhov piv ntawm RD / anti-butyl = 1.8 / 0.5.
Xaus
Txoj kev loj hlob ntawm high-temperature water vapor-resistant high elasticity EPDM roj hmab, lub hom phiaj yog ua kom tau raws li cov neeg kho tshuab cov khoom nyob rau hauv lub premise ntawm maximizing cov laus kuj thiab txo cov compression mus tas li deformation tus nqi.
(1) Cov roj hmab raw EPDM raug xaiv nrog 40% ~ 50% ntawm propylene thiab nruab nrab pawg ntawm ENB ua tus thib peb monomer.
(2) Lub tshuab vulcanization tau txais DCP / TAC, uas pab txhim kho kev sib txuas ntawm kev sib txuas, kev laus ua haujlwm thiab kev ua haujlwm ntawm cov txheej txheem.
(3) Siv siab elasticity carbon dub N762 kom ntau li ntau tau, uas tuaj yeem pab txhim kho kev tiv thaiv kev tawm tsam thiab kev laus, thiab tuaj yeem txo tus nqi.
(4) Txais kev tiv thaiv kev tiv thaiv ntawm antioxidant RD / antioxidant D, nrog kub-kub antioxidant RD ua lub ntsiab, thiab flexural qaug zog-resistant thiab ozone-resistant antioxidant D raws li ib tug pab.
(5) Cov txheej txheem tsim khoom tau txais qhov kub-kub theem nrab vulcanization kom nce qib ntawm vulcanization.
(6) Kev ua haujlwm ntawm EPDM hauv dej superheated thiab dej vapor yog pom tseeb zoo dua li hauv huab cua (tib yam kub). Tab sis txawm li ntawd los, nws siv sijhawm ntev ntawm qhov kub thiab txias tseem tsis tshaj 150 ℃ ; Qhov ntsuas kub ntawm 165 ℃ yog qhov tsim nyog, qhov siab tshaj plaws tsis tuaj yeem tshaj 180 ℃.
