1 Ku hlawuriwa ka rhaba leyi nga si swekiwaka
Plate heat exchanger rubber gasket hi nkarhi wun’we hi tlhelo ra gasi ra mahiselo yale henhla, tlhelo ra mati ra xiave xa ntshikelelo wale henhla, naswona nakambe va na ku hlangana na moya, swiyimo swa ntirho swilava ngopfu. Hikokwalaho, swilo leswi swifanele kuva swikota kahle swinene eka heat compression resistance, naswona swinga tiyisela medium ya mati xikan’we na steam ya wona. Eka swiyimo swotani, swifanele ku hlawula propylene mass fraction ya 40% ~ 50 % ya EPDM, hikuva muxaka lowu wa EPDM elasticity hi wona wa kahle swinene.
EPDM leyingana xiphemu xa mass xale henhla xa third monomer yina elasticity ya kahle xikan’we na low compression set; hambiswiritano, hikokwalaho ka degree yale henhla ya cross-linking, matimba ya tensile xikan’we na elongation eka break swile hansi, naswona ku tiya ka ku dyuhala na swona aswi kahle. Ku engetela kwalano, ku lwisana na ku dyuhala ka EPDM na ENB tani hi monomer ya vunharhu swa antswa kutlula ka EPDM na HD.
2 Endlelo ro horisa
Hiku angarhela, rhaba ya EPDM yinga endliwa vulcanized hi tinxaka timbirhi ta ti vulcanization systems: peroxide na sulfur yellow vulcanization. Xivumbeko xa cross-linking bond xa peroxide vulcanization system i CC bond, kasi xivumbeko xa cross-linking bond xa sulphur vulcanization system i CS bond. CC bond yitshamisekile swinene eka mahiselo kutlula CS bond, hikokwalaho rhaba ya EPDM leyi lwisanaka na mahiselo yale henhla yi vulcanized hi peroxide. Peroxide leyi tirhisiwaka ngopfu i DCP. Hiku tlakuka ka mpimo wa DCP, rhaba leyi vulcanized yi hundzuriwa hakatsongotsongo kusuka eka undersulfurization yosungula, matimba yale hansi xikan’we na deformation leyikulu kuya eka ku tlakuka ka matimba xikan’we nakuhunguteka ka deformation; kutani mpimo wa vulcanization wu engeteleriwa swinene, matimba ya sungula ku hunguteka naswona ku onhaka ku fika eka mpimo lowutsongo; eku heteleleni, endzhaku ka ku tlula mpimo ka vulcanizing agent, xiphemu xa molecular chain xi sungula ku tshoveka ku onhaka ka chain, matimba ya ya emahlweni ya hunguteka, naswona ku onhaka ka yona ku engeteleka hakatsongo-tsongo.
3.Xigwitsirisi
EPDM yi wela eka rhaba leyi nga riki ya crystalline, matimba ya rhaba yo ka yi nga swekiwanga a ya le henhla. Kambe endzhaku ko chela reinforcing filler, matimba ya engeteleka swinene. Ti fillers leti tiyisaka hi xitalo tina mbuyelo wutsongo eka ku tiya ka kuhisa, kambe ku engetela nhlayo ya filler swaha pfuneta ku antswisa ku tiya ka kuhisa ka rhaba, kambe switlhela swihunguta ku durha.
Loko grade ya carbon black yikula, compression set ya hunguteka, elasticity ya tlakuka naswona matimba ya hunguteka. Matimba ya N990 carbon black yale hansi swinene naswona swatika kuva ya lawula eka vuhumelerisi, hikokwalaho ayi tirhisiwi. Hiku hlawula N762 carbon black, nhlayo yale hansi ya compression set value yinga kumiwa. Leswaku ku olovisa ku hangalaka ka carbon black naku kuma matirhelo ya kahle ya vuhumelerisi, hlawula nhlayo yintsongo ya plasticizer paraffin oil, leyi fambelanaka swinene na ethylene propylene rubber.
4. Xiaki xa ku hlanganisa
Akuna unsaturated bond eka main chain ya EPDM, hambi leswi peroxide vulcanization yinga tirhisiwaka, kambe rivilo ra vulcanization ri nonoka, crosslinking efficiency yile hansi. Leswaku ku tiyisisiwa no hatlisisa endlelo ra vulcanization, swa laveka ku tirhisa crosslinking agent. TAC/GR leyi tshunguriweke ya antswa eka ku hangalasiwa na ku pima.
Hiku tlakuka ka nhlayo ya TAC/GR, matimba ya tensile, elongation at break xikan’we na compression permanent deformation ya vulcanized rubber swihunguteke, naswona MH value ya constant tensile stress yi tlakukile. Swinga voniwa leswaku crosslinking density ya vulcanized rubber yi antswisiwile, swivumbeko swa michini swihunguteke, kambe elasticity yive yikulu. Hi nkarhi lowu fanaka, nhlayo ya ML yi hungutekile, leswi kombaka leswaku viscosity ya Mooney yi hungutekile, ku khuluka ka rhaba ku antswisiwile, naswona a swi olova ku endliwa; ts1 hi xisekelo a yi cincanga, naswona ntikelo wa t 90 wu hungutiwile, naswona rivilo ra vulcanization swi le rivaleni leswaku ri antswisiwile. Matirhelo ya ku dyuhala a ya nga ri kahle eka 1.5phr ya TAC/GR. Leswi swinga vangiwa hi vukona bya cross-linking aid, ku endla leswaku peroxide vulcanization process yi tirha, ku pfuxeta nkarhi wa vulcanization, ku hunguta ku koteka ka ku tshoveka ka rubber molecular chain xikan’we na disproportionation eka mahiselo yale henhla. Loko nhlayo yitele ngopfu, swiendla leswaku ku dyuhala ka cross-linking ya rhaba naswona swihunguta ku tiya ka kuhisa ka EPDM. Endzhaku ko pimanisa, compression permanent deformation ya antswa eka 2phr, naswona ku tiya ka kuhisa aswi endliwi magandzelo ngopfu, hikokwalaho TAC/GR yitirhisiwa eka 2phr.
5.Xidlaya-switsongwatsongwana
EPDM yinga tirhisiwa nkarhi woleha eka 150 °C , kambe endzhaku ka 150 °C , ti molecules tisungula ku dyuhala hakatsongotsongo, naswona eka 180 °C , rubber molecular chain yita bola hakatsongotsongo. Leswaku yi ya emahlweni yi antswisa matirhelo ya yona eka mahiselo yale henhla, swiengeteri swo sirhelela swifanele kutirhisiwa. Eka water-vapor media, antioxidant RD yinga tirhisiwa, leyi tiyiselaka mahiselo yale henhla kambe ayi khumbi vulcanization hiku olova. Ku engetela kwalano, 0.5phr antioxidant D yinga tirhisiwa ku tiyisisa vuswikoti byo lwisana na oxygen emoyeni xikan’we naku antswisa ku lwisana na flexural fatigue. Nhlayo ya RD/anti-butyl=1.8/0.5.
Mahetelelo
Ku tumbuluxiwa ka rhaba ya EPDM ya high-temperature water-resistant high elasticity, nhlokomhaka i ku hlangana na swivumbeko swa michini ehansi ka xisekelo xo kurisa ku lwisana na ku dyuhala na ku hunguta nkoka wa compression permanent deformation.
( 1) Raba ya EPDM yo ka yi nga swekiwanga yi hlawuriwa hi 40%~50% ya propylene na xiphemu xa medium mass xa ENB tanihi monomer ya vunharhu.
( 2) Endlelo ra vulcanization ri amukela DCP/ TAC, leyi pfunetaka ku antswisa vukorhokeri bya crosslinking, ku lwisana na ku dyuhala na matirhelo ya phurosese.
( 3) Tirhisa high elasticity carbon black N762 hilaha swinga kotekaka hakona, leswinga pfunaka ku antswisa ku lwisana na media permeability na matirhelo ya ku dyuhala, naswona swinga hunguta ntsengo.
( 4) Amukela sisiteme ya nsirhelelo wa antioxidant RD/antioxidant D, na antioxidant ya mahiselo yale henhla ya RD tani hi yona leyikulu, na flexural fatigue-resistant na ozone-resistant antioxidant D tani hi leyi pfunetaka.
( 5) Endlelo ra vuhumelerisi ri amukela vulcanization ya vumbirhi ya mahiselo yale henhla ku engetela mpimo wa vulcanization.
(6) Swi le rivaleni leswaku matirhelo ya EPDM eka mati lama hiseke ngopfu ni le ka mpfula ya mati ya antswa ku tlula lama nga emoyeni (ku hisa loku fanaka). Kambe hambi swi ri tano, ku tirhisiwa ka yona ka nkarhi wo leha ka mahiselo ya ha ri ku tlula 150 °C ; mahiselo ya impact ya 165 °C ya lulamerile, yale henhla swinene ayi nge hundzi 180 °C.
