1 Zaɓin ɗanyen roba
Plate zafi Exchanger roba gasket a lokaci guda ta gefen gas na babban zafin jiki, ruwa gefen rawar da babban matsa lamba, da kuma samun lamba tare da iska, da aiki yanayi ne mafi wuya. Sabili da haka, kayan ya kamata ya zama mai kyau mai juriya na zafi mai zafi, kuma zai iya tsayayya da matsakaicin ruwa da tururi. A irin waɗannan yanayi, yakamata a zaɓi juzu'in taro na propylene na 40% ~ 50 % na EPDM, saboda irin wannan nau'in elasticity na EPDM shine mafi kyau.
EPDM tare da babban juzu'i mai yawa na monomer na uku yana da kyaun elasticity da ƙananan saitin matsawa; duk da haka, saboda babban matakin haɗin gwiwar haɗin gwiwa, ƙarfin ƙarfin ƙarfi da haɓakawa a lokacin hutu ya ragu, kuma juriya na tsufa kuma ba shi da kyau. Bugu da ƙari, juriya na tsufa na EPDM tare da ENB a matsayin monomer na uku ya fi na EPDM tare da HD.
2 Tsarin warkewa
Gabaɗaya, roba EPDM za a iya vulcanized da nau'i biyu na vulcanization tsarin: peroxide da sulfur yellow vulcanization. Tsarin haɗin giciye na tsarin vulcanization na peroxide shine CC bond, yayin da tsarin haɗin giciye na tsarin vulcanization na sulfur shine CS bond. Haɗin CC ya fi ƙarfin zafi fiye da haɗin CS, don haka robar EPDM mai jure zafin zafi yana ɓarna da peroxide. Mafi yawan amfani da peroxide shine DCP. Tare da karuwar adadin DCP, rubber vulcanized sannu a hankali yana canzawa daga rashin ƙarfi na farko, ƙarancin ƙarfi da babban nakasawa zuwa haɓaka ƙarfi da rage nakasawa; sa'an nan kuma matakin vulcanization yana ƙara ƙaruwa, ƙarfin ya fara raguwa, kuma nakasar ta kai ƙarami; a ƙarshe, bayan wuce haddi na vulcanizing wakili, wani ɓangare na kwayoyin halitta ya fara karya lalacewar sarkar, ƙarfin yana ci gaba da raguwa, kuma nakasa yana karuwa a hankali.
3.Filler
EPDM na roba ne wanda ba na crystalline ba, ƙarfin roba mai ƙarfi ba shi da ƙarfi. Amma bayan ƙara ƙarfafa filler, ƙarfin yana ƙaruwa sosai. Ƙarfafa filaye gabaɗaya yana da ɗan tasiri akan juriya na zafi, amma haɓaka adadin filler har yanzu yana taimakawa wajen haɓaka juriyar zafi na roba, amma kuma yana rage farashi.
Yayin da darajar baƙar fata na carbon ke ƙaruwa, saitin matsawa yana raguwa, haɓaka yana ƙaruwa, kuma ƙarfin yana raguwa. Ƙarfin N990 carbon baƙar fata yana da ƙarancin ƙarfi kuma yana da wahalar sarrafawa a samarwa, don haka ba a amfani da shi. Ta zaɓar N762 baƙar fata na carbon, ana iya samun ƙimar saita ƙarancin matsawa. Don sauƙaƙe watsawar carbon baƙar fata da kuma samun kyakkyawan aiki, zaɓi ƙaramin adadin man fetur na paraffin na filastik, wanda ya dace sosai da roba ethylene propylene.
4. Wakilin Crosslinking
Babu wani haɗin da ba a yarda da shi ba akan babban sarkar EPDM, kodayake ana iya amfani da ɓarna peroxide, amma saurin vulcanization yana jinkirin, haɓakar haɗin gwiwa yana da ƙasa. Domin daidaitawa da kuma hanzarta aiwatar da vulcanization, wajibi ne a yi amfani da wakili na crosslinking. TAC/GR ɗin da aka bi da shi ya fi kyau don tarwatsawa da aunawa.
Tare da haɓakar adadin TAC / GR, ƙarfin ƙarfin ƙarfi, haɓakawa a lokacin hutu da matsawa nakasar dindindin na roba mai ɓarna ya ragu, kuma ƙimar MH na damuwa na yau da kullun ya karu. Ana iya ganin cewa an inganta girman giciye na roba vulcanized, kayan aikin injiniya sun ragu, amma elasticity ya zama mafi girma. A lokaci guda, ƙimar ML ta ragu, yana nuna cewa dankowar Mooney ya ragu, an haɓaka ruwan roba, kuma yana da sauƙin sarrafawa; ts1 a zahiri bai canza ba, kuma an gajarta ƙimar t 90, kuma an inganta saurin vulcanization a fili. Ayyukan tsufa sun fi talauci a 1.5phr na TAC/GR. Wannan na iya zama saboda kasancewar taimakon haɗin kai, kunna tsarin vulcanization peroxide, rage lokacin vulcanization, rage yiwuwar raguwar sarkar kwayoyin roba da rashin daidaituwa a babban zafin jiki. Lokacin da adadin ya yi yawa, yana haɓaka haɓaka haɓakar haɗin gwiwa na roba kuma yana rage juriya na zafi na EPDM. Bayan kwatantawa, matsawa nakasar dindindin ta fi kyau a 2phr, kuma ba a sadaukar da juriya mai zafi sosai, don haka ana amfani da TAC/GR a 2phr.
5.Antioxidant
Ana iya amfani da EPDM na dogon lokaci a 150 ℃ , amma bayan 150 ℃ , kwayoyin suna fara tsufa a hankali, kuma a 180 ℃ , sarkar kwayoyin roba za ta rushe a hankali. Don ƙara haɓaka aikin sa a yanayin zafi mai girma, dole ne a yi amfani da abubuwan da ke kare kariya. Game da kafofin watsa labarai na tururi, ana iya amfani da antioxidant RD, wanda ke da juriya ga yanayin zafi amma ba ya yin tasiri cikin sauƙi. Bugu da ƙari, ana iya amfani da 0.5phr antioxidant D don ƙarfafa ikon yin tsayayya da iskar oxygen a cikin iska da kuma inganta juriya na gajiya. Rabon RD/anti-butyl=1.8/0.5.
Kammalawa
Haɓaka babban zafin jiki na ruwa mai juriya mai ƙarfi na roba na EPDM, mayar da hankali shine saduwa da kaddarorin inji a ƙarƙashin yanayin haɓaka juriya na tsufa da rage ƙimar nakasar dindindin.
( 1) An zaɓi ɗanyen roba na EPDM tare da 40% ~ 50% na propylene da matsakaicin juzu'i na ENB a matsayin monomer na uku.
(2) Tsarin vulcanization yana ɗaukar DCP/TAC, wanda ke taimakawa haɓaka haɓakar haɗin gwiwa, juriyar tsufa da aikin aiwatarwa.
(3) Yi amfani da babban elasticity carbon baki N762 kamar yadda zai yiwu, wanda zai iya taimakawa wajen inganta juriya ga aikin watsa labaru da aikin tsufa, kuma zai iya rage farashin.
(4) Dauki tsarin kariya na antioxidant RD/antioxidant D, tare da babban zafin jiki antioxidant RD a matsayin babban daya, da flexural gajiya-resistant da ozone-resistant antioxidant D a matsayin mai taimako daya.
( 5) Tsarin samarwa yana ɗaukar vulcanization na biyu na zafin jiki mai zafi don ƙara ƙimar vulcanization.
(6) Ayyukan EPDM a cikin ruwa mai zafi da tururin ruwa a fili ya fi na iska (zazzabi iri ɗaya). Amma duk da haka, amfani da zafin jiki na dogon lokaci har yanzu bai wuce 150 ℃ ba ; tasirin zafin jiki na 165 ℃ ya dace, mafi girman ba zai iya wuce 180 ℃ ba.
