1 Rɔba a wɔmfa nhyehyɛ mu a wɔpaw
Plate heat exchanger rubber gasket bere koro no ara mu denam gas fã a ɛyɛ hyew a ɛkorɔn, nsu fã no dwumadi a nhyɛso kɛse, na nso wɔ contact ne mframa, adwumayɛ tebea horow no yɛ nea ɛhwehwɛ kɛse. Enti, ɛsɛ sɛ ade no yɛ ɔhyew a ɛko tia yiye paa, na ebetumi agyina nsu ne ne nsuonwini ano. Wɔ tebea horow a ɛte saa mu no, ɛsɛ sɛ paw propylene mass fraction a ɛyɛ 40% ~ 50 % of EPDM, efisɛ saa EPDM elasticity yi ne nea eye sen biara.
EPDM a ɛwɔ mass fraction a ɛkorɔn a ɛyɛ monomer a ɛto so abiɛsa no wɔ elasticity pa ne compression set a ɛba fam; nanso esiane sɛ cross-linking no kɛse nti, ahoɔden a ɛtwetwe ne elongation bere a wɔabubu no sua, na onyin a ɛko tia no nso nyɛ papa. Bio nso, EPDM a ENB yɛ monomer a ɛto so abiɛsa no onyin a ɛko tia no ye sen EPDM a HD wom no.
2 Curing nhyehyɛe
Mpɛn pii no, wobetumi de vulcanization nhyehyɛe ahorow abien ayɛ EPDM rɔba: peroxide ne sulfur yellow vulcanization. Peroxide vulcanization nhyehyɛe no cross-linking bond nhyehyɛe no yɛ CC bond, bere a cross-linking bond nhyehyɛe a ɛwɔ sulfur vulcanization nhyehyɛe no mu no yɛ CS bond. CC bond no yɛ nea ɛyɛ hyew kɛse sen CS bond no, enti wɔde peroxide yɛ EPDM rɔba a ɛko tia ɔhyew a ɛkɔ soro no vulcanized. Peroxide a wɔde di dwuma kɛse ne DCP. DCP dodow a ɛkɔ soro no, vulcanized rɔba no dannan nkakrankakra fi mfiase undersulfurization, ahoɔden a ɛba fam ne deformation kɛse kɔ ahoɔden a ɛkɔ soro ne deformation so tew; afei vulcanization dodow no kɔ soro bio, ahoɔden no fi ase so tew, na deformation no du nea ɛba fam koraa; awiei koraa no, bere a wɔde vulcanizing aduru a ɛboro so akyi no, molecule nkɔnsɔnkɔnsɔn no fã bi fi ase bubu nkɔnsɔnkɔnsɔn no a ɛsɛe no, ahoɔden no kɔ so so tew, na deformation no kɔ soro nkakrankakra.
3.Filler a wɔde hyɛ mu
EPDM yɛ rɔba a ɛnyɛ ahwehwɛ dea, rɔba a wɔannoa no ahoɔden nyɛ kɛse. Nanso bere a wɔde reinforcing filler aka ho akyi no, ahoɔden no kɔ soro kɛse. Mpɛn pii no, nneɛma a wɔde hyɛ mu den no nni nkɛntɛnso kɛse biara wɔ ɔhyew a ɛko tia so, nanso sɛ wɔma nneɛma a wɔde hyɛ mu no dodow kɔ soro a, ɛda so ara boa ma ɔhyew a rɔba no gyina ano no tu mpɔn, nanso ɛtew ɛka so nso.
Bere a carbon black grade kɔ soro no, compression set no so tew, elasticity no kɔ soro, na ahoɔden no so tew. N990 carbon black ahoɔden sua dodo na ɛyɛ den sɛ wobedi so wɔ ne yɛ mu, enti wɔmfa nni dwuma. Ɛdenam N762 carbon black a wobɛpaw so no, wobetumi anya compression set value a ɛba fam. Sɛnea ɛbɛyɛ a ɛbɛyɛ mmerɛw sɛ wobɛpete carbon black na woanya adwumayɛ ho adwumayɛ pa no, paw plasticizer paraffin ngo kakraa bi, a ɛne ethylene propylene rɔba hyia yiye.
4. Crosslinking aduru a wɔde di dwuma
Nkitahodi biara nni EPDM nkɔnsɔnkɔnsɔn titiriw no so, ɛwom sɛ wobetumi de peroxide vulcanization adi dwuma de, nanso vulcanization ahoɔhare no yɛ brɛoo, crosslinking efficiency sua. Sɛnea ɛbɛyɛ a vulcanization nhyehyɛe no bɛgyina na ayɛ ntɛmntɛm no, ɛho hia sɛ wɔde crosslinking agent di dwuma. TAC/GR a wɔayɛ ho adwuma no ye ma apete ne nea wɔkari.
Bere a TAC/GR dodow kɔɔ soro no, ahoɔden a ɛtwetwe, elongation wɔ break ne compression permanent deformation a ɛwɔ vulcanized rubber mu no so tew, na MH bo a ɛwɔ tensile stress a ɛkɔ so daa no kɔɔ soro. Yebetumi ahu sɛ wɔmaa crosslinking density a ɛwɔ vulcanized rubber mu no yɛɛ yiye, mfiri no su so tew, nanso elasticity no yɛɛ kɛse. Bere koro no ara mu no, ML bo no so tew, na ɛkyerɛ sɛ Mooney viscosity no so tew, rɔba no nsu a ɛkɔ mu no yɛɛ kɛse, na na ɛnyɛ den sɛ wɔbɛyɛ ho adwuma; Na ts1 no nsakrae titiriw, na wɔtew t 90 bo no so, na ɛda adi sɛ vulcanization ahoɔhare no yɛɛ yiye. Mpanyinyɛ adwumayɛ no yɛɛ papa wɔ 1.5phr a ɛyɛ TAC/GR. Eyi betumi afi cross-linking mmoa a ɛwɔ hɔ, activate peroxide vulcanization nhyehyɛe, activate vulcanization bere, tew hokwan a ebetumi aba sɛ rɔba molecule nkɔnsɔnkɔnsɔn abubu ne disproportionation wɔ ɔhyew a ɛkorɔn. Sɛ dodow no dɔɔso dodo a, ɛma rɔba no cross-linking a ɛyɛ dedaw no yɛ kɛse na ɛtew ɔhyew a EPDM no gyina ano no so. Sɛ yɛde toto ho wie a, compression permanent deformation no ye wɔ 2phr, na wɔmfa ɔhyew a ɛko tia no mmɔ afɔre kɛse, enti wɔde TAC/GR no di dwuma wɔ 2phr.
5.Nnuru a ɛko tia ɔyare mmoawa
Wobetumi de EPDM adi dwuma bere tenten wɔ 150 °C , nanso sɛ ɛboro 150 °C so a , molecule ahorow no fi ase nyin nkakrankakra, na sɛ ɛyɛ 180 °C a, rɔba molecule nkɔnsɔnkɔnsɔn no bɛporɔw nkakrankakra. Sɛnea ɛbɛyɛ na ne dwumadi atu mpɔn kɛse wɔ ɔhyew a ɛkɔ soro mu no, ɛsɛ sɛ wɔde nneɛma a wɔde bɔ ho ban di dwuma. Wɔ nsuo a ɛyɛ nsuo a ɛyɛ hyew ho no, wobetumi de antioxidant RD a ɛko tia ɔhyew a ɛkɔ soro nanso ɛnyɛ mmerɛw sɛ ɛbɛka vulcanization no adi dwuma. Bio nso, wobetumi de 0.5phr antioxidant D adi dwuma de ahyɛ tumi a ɛko tia oxygen a ɛwɔ mframa mu no mu den na ama flexural fatigue resistance no atu mpɔn. Nkyɛmu a ɛwɔ RD/anti-butyl=1.8/0.5 mu.
Awie
Nkɔso a ɛkorɔn-ɔhyew nsu vapor-resistant high elasticity EPDM rɔba, adwene ne sɛ wobehyia mfiridwuma su ahorow ase wɔ adwene a ɛne sɛ maximizing onyin resistance na tew compression daa deformation bo.
( 1) Wɔpaw EPDM rɔba a wɔannoa no ne 40% ~ 50% propylene ne medium mass fraction of ENB sɛ monomer a ɛto so abiɛsa.
( 2) Vulcanization nhyehyɛe no fa DCP/ TAC, a ɛboa ma crosslinking efficiency, onyin resistance ne process adwumayɛ tu mpɔn.
( 3) Fa high elasticity carbon black N762 di dwuma sɛnea wubetumi, a ebetumi aboa ma sɛnea wɔko tia nsɛm ho amanneɛbɔfo a ɛtumi fa mu ne onyin adwumayɛ atu mpɔn, na ebetumi atew ɛka so.
( 4) Fa ahobammɔ nhyehyɛe a ɛne antioxidant RD/antioxidant D no tom, a ɔhyew a ɛkɔ soro a ɛko tia ɔyare mmoawa RD ne nea ɛho hia titiriw, ne flexural fatigue-resistant ne ozone-resistant antioxidant D sɛ nea ɛboa.
( 5) Adeyɛ nhyehyɛe no fa ɔhyew a ɛkorɔn vulcanization a ɛto so abien tom na ama vulcanization dodow akɔ soro.
(6) Ɛda adi sɛ sɛnea EPDM yɛ adwuma wɔ nsu a ɛyɛ hyew dodo ne nsu a ɛyɛ hyew mu no ye sen nea ɛwɔ mframa mu (ɔhyew koro). Nanso ɛno mpo no, ɔhyew a ɔde di dwuma bere tenten no da so ara ntra 150 °C ; impact temperature a ɛyɛ 165 °C no fata, nea ɛkorɔn sen biara no ntumi ntra 180 °C.
