1. Isingeniso
I-EVA yisifinyezo se-ethylene vinyl acetate copolymer, i-polyolefin polymer. Ngenxa yokushisa kwayo okuphansi kokuncibilika, ukugeleza okuhle, i-polarity kanye nezinto ezingezona i-halogen, futhi ingahambisana nezinhlobo ezahlukene zama-polymer kanye ne-mineral powders, izakhiwo eziningi zemishini nezomzimba, izakhiwo zikagesi kanye nebhalansi yokusebenza kokucubungula, futhi intengo ayiphezulu, ukutholakala kwemakethe kwanele, ngakho kokubili njengezinto zokuvala ikhebula, zingasetshenziswa futhi njengezinto zokugcwalisa, zokufaka isivikelo; zingenziwa zibe izinto ze-thermoplastic, futhi zingenziwa zibe izinto zokuxhumanisa ze-thermosetting.
Uhlu olubanzi lokusetshenziswa kwe-EVA, olunezithibi zomlilo, lungenziwa lube yisithibi esingenawo umusi noma isithibi sikaphethiloli se-halogen esincane; khetha okuqukethwe okuphezulu kwe-VA kwe-EVA njengoba izinto eziyisisekelo zingenziwa futhi zibe yizinto ezingamelani namafutha; khetha inkomba yokuncibilika kwe-EVA ephakathi nendawo, engeza izikhathi ezi-2 kuya kwezi-3 zokugcwaliswa kwezithibi zomlilo ze-EVA ezingenziwa ukuze kusebenze inqubo yokukhipha kanye nentengo yezinto ezithibi zomoya-mpilo ezilinganiselayo (ukugcwalisa).
Kuleli phepha, kusukela ezimpahleni zesakhiwo se-EVA, ukwethulwa kokusetshenziswa kwayo embonini yekhebula kanye namathemba okuthuthukiswa.
2. Izakhiwo zesakhiwo
Lapho kukhishwa ukwenziwa, ukushintsha isilinganiso sezinga le-polymerisation n/m kungakhiqiza okuqukethwe kwe-VA kusuka ku-5 kuya ku-90% we-EVA; ukwandisa izinga le-polymerisation eliphelele kungakhiqiza isisindo sama-molecule kusuka kumashumi ezinkulungwane kuya kumakhulu ezinkulungwane ze-EVA; okuqukethwe kwe-VA ngaphansi kuka-40%, ngenxa yokuba khona kwe-crystallisation engaphelele, ukunwebeka okungekuhle, okwaziwa kakhulu ngokuthi ipulasitiki ye-EVA; lapho okuqukethwe kwe-VA kungaphezu kuka-40%, i-elastomer efana nerabha engena-crystallisation, yaziwa kakhulu ngokuthi irabha ye-EVM.
1. 2 Izakhiwo
Uchungechunge lwama-molecule lwe-EVA luyisakhiwo esigcwele esiqondile, ngakho-ke lunokuguga okuhle kokushisa, isimo sezulu kanye nokumelana ne-ozone.
Iketanga eliyinhloko le-molecule ye-EVA alinazo izibopho eziphindwe kabili, indandatho ye-benzene, i-acyl, amaqembu e-amine namanye amaqembu okulula ukuwabhema uma ushisa, iketanga eliseceleni nalo alinazo i-methyl, i-phenyl, i-cyano namanye amaqembu okulula ukuwabhema uma ushisa. Ngaphezu kwalokho, i-molecule ngokwayo ayinazo izakhi ze-halogen, ngakho-ke ifaneleka kakhulu isisekelo sikaphethiloli esingenantuthu ephansi ye-halogen.
Ubukhulu obukhulu beqembu le-vinyl acetate (VA) ku-EVA side chain kanye ne-medium polarity yayo kusho ukuthi kokubili kuvimbela ukuthambekela komgogodla we-vinyl ukuthi uqine futhi kuhambisane kahle nama-mineral fillers, okudala izimo zamafutha okuvimbela ukusebenza okuphezulu. Lokhu kuyiqiniso ikakhulukazi kuma-resistance aphansi entuthu kanye nama-halogen-free, njengoba ama-flame retardants anokuqukethwe okungaphezu kuka-50% wevolumu [isb. Al(OH) 3, Mg(OH) 2, njll.] kumele engezwe ukuze kuhlangatshezwane nezidingo zezindinganiso zekhebula zokuthi ama-flame retardants aphakathi kuya phezulu. I-EVA enokuqukethwe kwe-VA okuphakathi kuya phezulu isetshenziswa njengesisekelo sokukhiqiza amafutha aphansi entuthu kanye nama-halogen-free flame retardants anezakhiwo ezinhle kakhulu.
Njengoba iqembu le-vinyl acetate le-EVA side chain (VA) liyi-polar, uma okuqukethwe kwe-VA kuphakeme, i-polymer i-polar kakhulu futhi ukumelana kwamafutha kuba ngcono. Ukumelana kwamafutha okudingekayo embonini yezintambo kubhekisela kakhulu ekhonweni lokumelana namafutha amaminerali angewona ama-polar noma abuthakathaka. Ngokomgomo wokuhambisana okufanayo, i-EVA enokuqukethwe okuphezulu kwe-VA isetshenziswa njengezinto eziyisisekelo ukukhiqiza isithiyo sikaphethiloli esingenantuthu ne-halogen esinokumelana okuhle kwamafutha.
Ama-molecule e-EVA ekusebenzeni kwe-athomu ye-alpha-olefin H asebenza kakhulu, kuma-radical e-peroxide noma umphumela wemisebe ye-electron enamandla aphezulu kulula ukuwuthatha, ukusabela kwe-cross-linking kwe-H, kuba yipulasitiki noma irabha exhunywe nge-cross-linking, kungenziwa izidingo zokusebenza ezidingayo zezinto ezikhethekile zentambo nekhebula.
Ukwengezwa kweqembu le-vinyl acetate kwenza izinga lokushisa lokuncibilika kwe-EVA lehle kakhulu, futhi inani lamaketanga amafushane e-VA angenza ukugeleza kwe-EVA kwande. Ngakho-ke, ukusebenza kwayo kokukhipha kungcono kakhulu kunesakhiwo sama-molecule se-polyethylene efanayo, okuba yizinto eziyisisekelo ezikhethwayo zezinto zokuvikela ezisebenzisa i-semi-conductive kanye nezithiyo zikaphethiloli ezingenayo i-halogen ne-halogen.
2 Izinzuzo zomkhiqizo
2. 1 Ukusebenza okubiza kakhulu
Izakhiwo ze-EVA ezingokomzimba nezingokwemishini, ukumelana nokushisa, ukumelana nesimo sezulu, ukumelana ne-ozone, izakhiwo zikagesi zinhle kakhulu. Khetha ibanga elifanele, kungenziwa ukumelana nokushisa, ukusebenza okubambezela ilangabi, kodwa futhi namafutha, izinto ezikhethekile zekhebula ezimelana nokuncibilika.
Izinto ze-EVA ze-thermoplastic zisetshenziswa kakhulu ngokuqukethwe kwe-VA okungu-15% kuya ku-46%, kanye ne-melt index engu-0.5 kuya ku-4 grades. I-EVA inabakhiqizi abaningi, izinhlobo eziningi, izinketho eziningi, amanani aphakathi nendawo, ukuphakelwa okwanele, abasebenzisi badinga kuphela ukuvula ingxenye ye-EVA yewebhusayithi, uhlobo, ukusebenza, intengo, indawo yokulethwa ngokushesha, ungakhetha, kulula kakhulu.
I-EVA iyi-polyolefin polymer, kusukela ekuthambekeni nasekusetshenzisweni kokuqhathanisa ukusebenza, kanye nezinto ze-polyethylene (PE) kanye nezinto zekhebula ze-polyvinyl chloride (PVC) ezithambile ziyafana. Kodwa ucwaningo olwengeziwe, uzothola i-EVA kanye nezinhlobo ezimbili zezinto ezingenhla uma kuqhathaniswa nokuphakama okungenakuphindwa.
2. 2 ukusebenza kahle kakhulu kokucubungula
I-EVA ekusetshenzisweni kwekhebula ivela ezintweni zokuvikela ikhebula ezisebenza ngogesi ophakathi nendawo kanye nangaphandle kokuqala, futhi kamuva yanwetshwa yaba yisithiyo sikaphethiloli esingena-halogen. Lezi zinhlobo ezimbili zezinto kusukela embonweni wokucubungula zibhekwa “njengezinto ezigcwele kakhulu”: izinto zokuvikela ngenxa yesidingo sokwengeza inani elikhulu le-carbon black eqhubayo nokwenza i-viscosity yayo ikhuphuke, uketshezi lwehle kakhulu; uphethiloli ovimbela ilangabi ongena-halogen udinga ukwengeza inani elikhulu lezinto zokuvimbela ilangabi ezingena-halogen, kanye ne-viscosity yezinto ezingena-halogen yande kakhulu, uketshezi lwehle kakhulu. Isixazululo ukuthola i-polymer engamukela imithamo emikhulu ye-filler, kodwa futhi ine-viscosity encibilikayo ephansi kanye noketshezi oluhle. Ngenxa yalesi sizathu, i-EVA iyindlela ekhethwayo.
I-EVA melt viscosity enezinga lokushisa lokucubungula i-extrusion kanye nesilinganiso sokushefa kuzokhulisa ukwehla okusheshayo, umsebenzisi udinga kuphela ukulungisa izinga lokushisa le-extruder kanye nesivinini sesikulufu, ungenza ukusebenza okuhle kakhulu kwemikhiqizo yensimbi neyekhebula. Inani elikhulu lezicelo zasekhaya nezangaphandle libonisa ukuthi, ezintweni ezigcwele kakhulu ezingenayo i-halogen engenamusi, ngoba i-viscosity inkulu kakhulu, i-melt index incane kakhulu, ngakho-ke ukusetshenziswa kwe-low compression ratio screw (compression ratio engaphansi kuka-1.3) extrusion kuphela, ukuqinisekisa ikhwalithi enhle ye-extrusion. Izinto ze-EVM ezisekelwe enjolobeni ezine-vulcanising agents zingakhishwa kokubili kuma-extruder enjoloba kanye nama-extruder ajwayelekile. Inqubo elandelayo ye-vulcanisation (cross-linking) ingenziwa nge-thermochemical (peroxide) cross-linking noma nge-electron accelerator irradiation cross-linking.
2. 3 Kulula ukuyishintsha nokuyivumelanisa nezimo
Izintambo nezintambo zikhona yonke indawo, kusukela esibhakabhakeni kuya phansi, kusukela ezintabeni kuya olwandle. Abasebenzisi bezidingo zezintambo nezintambo nabo bayahlukahluka futhi bayaxaka, kuyilapho isakhiwo sezintambo nezintambo sifana, umehluko wokusebenza kwazo ubonakala kakhulu ezintweni zokumboza i-insulation kanye ne-sheath.
Kuze kube manje, kokubili ekhaya nakwamanye amazwe, i-PVC ethambile isalokhu iyingxenye enkulu yezinto zokwakha i-polymer ezisetshenziswa embonini yezintambo. Kodwa-ke, njengoba ulwazi ngokuvikelwa kwemvelo kanye nentuthuko esimeme lukhula.
Izinto ze-PVC zivinjelwe kakhulu, ososayensi benza konke okusemandleni ukuthola ezinye izinto esikhundleni se-PVC, okuthembisa kakhulu kuzo yi-EVA.
I-EVA ingaxutshwa nezinhlobo ezahlukene zama-polymer, kodwa futhi nezinhlobo ezahlukene zezimpushana zamaminerali kanye nezinsiza zokucubungula ezihambisanayo, imikhiqizo exutshiwe ingenziwa ibe yipulasitiki ye-thermoplastic yamakhebula epulasitiki, kodwa futhi ibe yirabha exhunywe ngezintambo zerabha. Abaklami bokwenza bangasekelwa ezidingweni zomsebenzisi (noma ezijwayelekile), i-EVA njengento eyisisekelo, ukuze benze ukusebenza kwezinto kuhlangabezane nezidingo.
Ububanzi besicelo se-EVA obungu-3
3. 1 Isetshenziswa njengento yokuvikela eqhuba kancane izintambo zamandla ezinamandla aphezulu
Njengoba sonke sazi, izinto eziyinhloko zezinto zokuvikela zingumnyama wekhabhoni oqhubayo, epulasitikini noma esisekelo serabha ukuze kufakwe inani elikhulu lekhabhoni emnyama kuzolimaza kakhulu ukugeleza kwezinto zokuvikela kanye nokushelela kwezinga lokukhipha. Ukuze kuvinjelwe ukukhishwa okungaphelele ezintanjeni ezinamandla aphezulu, izihlangu zangaphakathi nezangaphandle kumele zibe zincane, zicwebezele, zikhanye futhi zifane. Uma kuqhathaniswa namanye ama-polymer, i-EVA ingakwenza lokhu kalula. Isizathu salokhu ukuthi inqubo yokukhipha i-EVA inhle kakhulu, igeleza kahle, futhi ayithambekeli ekuqhekekeni. Izinto zokuvikela zihlukaniswe ngezigaba ezimbili: zigoqwe kumqhubi ngaphandle obizwa ngokuthi isihlangu sangaphakathi - ngezinto zesikrini sangaphakathi; zigoqwe ku-insulation ngaphandle obizwa ngokuthi isihlangu sangaphandle - ngezinto zesikrini sangaphandle; izinto zesikrini sangaphakathi ikakhulukazi ziyi-thermoplastic. Izinto zesikrini sangaphakathi ikakhulukazi ziyi-thermoplastic futhi ngokuvamile zisekelwe ku-EVA enokuqukethwe kwe-VA okungu-18% kuya ku-28%; izinto zesikrini sangaphandle zixhumene kakhulu futhi ziyaqhekeka futhi ngokuvamile zisekelwe ku-EVA enokuqukethwe kwe-VA okungu-40% kuya ku-46%.
3. 2 Amafutha avimbela ilangabi asebenzisa i-thermoplastic kanye nahlanganisiwe
I-polyolefin evimbela ilangabi ye-thermoplastic isetshenziswa kabanzi embonini yezintambo, ikakhulukazi ngezidingo zezintambo zasolwandle, izintambo zikagesi kanye nezintambo zokwakha zezinga eliphezulu. Amazinga okushisa azo okusebenza isikhathi eside asukela ku-70 kuya ku-90 °C.
Ngezintambo zamandla ezisebenza ngogesi eziphakathi nendawo neziphezulu ezingama-10 kV nangaphezulu, ezinezidingo eziphezulu kakhulu zokusebenza kukagesi, izakhiwo ezivimbela ilangabi zithwalwa kakhulu yi-external sheath. Kwezinye izakhiwo noma amaphrojekthi adinga imvelo, izintambo ziyadingeka ukuthi zibe nentuthu encane, ezingenayo i-halogen, ubuthi obuphansi noma intuthu encane kanye nezakhiwo ze-halogen ephansi, ngakho-ke ama-polyolefin avimbela ilangabi e-thermoplastic ayisisombululo esisebenzayo.
Ngezinhloso ezithile ezikhethekile, ububanzi bangaphandle abubukhulu, ukumelana nokushisa ku-105 ~ 150 ℃ phakathi kwekhebula elikhethekile, izinto ze-polyolefin ezixhumene kakhulu nezivimbela ilangabi, ukuxhumanisa kwayo kungakhethwa ngumkhiqizi wekhebula ngokuya ngezimo zabo zokukhiqiza, kokubili umusi wendabuko ocindezelwe kakhulu noma ubhavu kasawoti oshisayo kakhulu, kodwa futhi kuyatholakala ngendlela yokushisa ye-electron accelerator room temperature irradiation. Izinga lokushisa layo lokusebenza lesikhathi eside lihlukaniswe ngamafayela amathathu angu-105 ℃, 125 ℃, 150 ℃, isitshalo sokukhiqiza singenziwa ngokuya ngezidingo ezahlukene zabasebenzisi noma amazinga, isithiyo sikaphethiloli esingenalo i-halogen noma esiqukethe i-halogen.
Kwaziwa kahle ukuthi ama-polyolefin angama-polymer angewona ama-polar noma abuthakathaka. Njengoba efana namafutha amaminerali ku-polarity, ama-polyolefin abhekwa kakhulu njengangamelani kakhulu namafutha ngokwesimiso sokuhambisana okufanayo. Kodwa-ke, izindinganiso eziningi zekhebula ekhaya nakwamanye amazwe nazo zithi ukumelana okuxhumene kufanele futhi kube nokumelana okuhle namafutha, izinyibilikisi ngisho nakuma-slurry kawoyela, ama-acid nama-alkali. Lokhu kuyinselele kubacwaningi bezinto ezibonakalayo, manje, kungakhathaliseki ukuthi eShayina noma kwamanye amazwe, lezi zinto ezidinga amandla sezithuthukisiwe, futhi izinto eziyisisekelo zazo ziyi-EVA.
3. 3 Izinto zokuvimbela umoya-mpilo
Izintambo eziningi ezinama-stranded zinezikhala eziningi phakathi kwama-cores okudingeka zigcwaliswe ukuqinisekisa ukubukeka kwekhebula eliyindilinga, uma ukugcwalisa ngaphakathi kwe-sheath yangaphandle kwenziwe ngesithiyo sikaphethiloli esingenayo i-halogen. Lolu ngqimba lokugcwalisa lusebenza njengesithiyo somlilo (i-oxygen) lapho ikhebula lisha ngakho-ke lwaziwa ngokuthi “isithiyo sika-oxygen” embonini.
Izidingo eziyisisekelo zezinto ezivimbela umoya-mpilo yilezi: izakhiwo ezinhle zokukhipha umoya-mpilo, ukubambezeleka komlilo okungenalo i-halogen (inkomba yomoya-mpilo ngokuvamile ingaphezu kuka-40) kanye nezindleko eziphansi.
Lesi sivimbelo se-oxygen sisetshenziswe kakhulu embonini yezintambo iminyaka engaphezu kweshumi futhi siholele ekuthuthukisweni okukhulu ekubambezelekeni komlilo kwezintambo. Isivimbelo se-oxygen singasetshenziswa kokubili izintambo ezivimbela umlilo ezingenayo i-halogen kanye nezintambo ezivimbela umlilo ezingenayo i-halogen (isb. i-PVC). Umkhuba omkhulu ukhombisile ukuthi izintambo ezinesivimbelo se-oxygen cishe ziphumelela ekuhlolweni okukodwa kokushiswa okuqondile kanye nokushiswa kwenqwaba.
Ngokombono wokwakheka kwezinto, le nto yokuvimbela umoya-mpilo empeleni "iyi-filler ephezulu kakhulu", ngoba ukuze kuhlangatshezwane nezindleko eziphansi, kuyadingeka ukusebenzisa i-filler ephezulu, ukuze kufezwe i-oxygen index ephezulu kumele futhi wengeze isilinganiso esiphezulu (izikhathi ezi-2 kuya kwezi-3) se-Mg (OH) 2 noma i-Al (OH) 3, futhi ukuze kukhishwe okuhle futhi kumele ukhethe i-EVA njengezinto eziyisisekelo.
3. 4 Izinto zokubopha ze-PE eziguquliwe
Izinto zokubopha i-polyethylene zithambekele ezinkingeni ezimbili: okokuqala, zithambekele ekuqhekekeni (okungukuthi i-sharkskin) ngesikhathi sokukhipha; okwesibili, zithambekele ekuqhekekeni kokucindezeleka kwemvelo. Isixazululo esilula ukwengeza ingxenye ethile ye-EVA ekwakhiweni. Uma isetshenziswa njenge-EVA eguquliwe isebenzisa kakhulu okuqukethwe kwe-VA okuphansi kwebanga, inkomba yayo yokuncibilika ephakathi kuka-1 kuya ku-2 iyafaneleka.
4. Amathemba entuthuko
(1) I-EVA isetshenziswe kabanzi embonini yekhebula, inani lonyaka ekukhuleni kancane kancane nangokuzinzile. Ikakhulukazi eminyakeni eyishumi edlule, ngenxa yokubaluleka kokuvikelwa kwemvelo, ukumelana nophethiloli okusekelwe ku-EVA kube yintuthuko esheshayo, futhi kuye kwathatha indawo ngokwengxenye yesitayela sekhebula elisekelwe ku-PVC. Ukusebenza kwayo okuhle kakhulu kwezindleko kanye nokusebenza okuhle kakhulu kwenqubo yokukhipha kunzima ukukushintsha noma yiziphi ezinye izinto.
(2) ukusetshenziswa kwe-resin ye-EVA minyaka yonke embonini yekhebula cishe ngamathani ayi-100,000, ukukhetha izinhlobo ze-resin ye-EVA, okuqukethwe kwe-VA kusukela phansi kuya phezulu kuzosetshenziswa, kuhlanganiswe nezinto zekhebula. Usayizi webhizinisi awukhulu, usakazeke ebhizinisini ngalinye minyaka yonke kuphela ezinkulungwaneni zamathani e-resin ye-EVA phezulu naphansi, ngakho-ke ngeke kube ukunakwa okukhulu kwebhizinisi embonini ye-EVA. Isibonelo, inani elikhulu kakhulu lezinto eziyisisekelo ezivimbela ilangabi ezingenalo i-halogen, ukukhetha okuyinhloko kwe-VA / MI = 28 /2 ~ 3 ye-resin ye-EVA (njenge-US DuPont's EVA 265 #). Futhi leli banga lokucaciswa kwe-EVA kuze kube manje alikho abakhiqizi basekhaya abangakhiqiza futhi banikeze. Ingasaphathwa eyokuqukethwe kwe-VA okungaphezu kwama-28, kanye nenkomba yokuncibilikisa engaphansi kwama-3 kwezinye izinhlobo zokukhiqizwa kwe-resin ye-EVA kanye nokuhlinzekwa.
(3) izinkampani zakwamanye amazwe ezikhiqiza i-EVA ngenxa yokungabikho kwabancintisani basekhaya, futhi intengo ibilokhu iphakeme isikhathi eside, icindezela kakhulu umdlandla wokukhiqiza iziteshi zekhebula zasekhaya. Ngaphezu kuka-50% wokuqukethwe kwe-VA kwe-EVM yohlobo lwerabha, yinkampani yakwamanye amazwe ebusa, futhi intengo ifana nokuqukethwe kwe-VA komkhiqizo izikhathi ezimbili kuya kwezingu-3. Amanani aphezulu kangaka, nawo, athinta inani lalolu hlobo lwerabha lwe-EVM, ngakho-ke imboni yekhebula ifuna abakhiqizi be-EVA basekhaya, ukuthi bathuthukise izinga lokukhiqizwa kwe-EVA ekhaya. Ukukhiqizwa okwengeziwe kwemboni kube ukusetshenziswa kakhulu kwe-resin ye-EVA.
(4) Ithembele egagasini lokuvikelwa kwemvelo enkathini yomhlaba wonke, imboni yezintambo ibheka i-EVA njengesisekelo esingcono kakhulu sokumelana nophethiloli onobungani nemvelo. Ukusetshenziswa kwe-EVA kukhula ngesilinganiso esingu-15% ngonyaka futhi umbono uyathembisa kakhulu. Inani kanye nesilinganiso sokukhula kwezinto zokuvikela kanye nokukhiqizwa kwekhebula lamandla kagesi eliphakathi neliphezulu kanye nesilinganiso sokukhula, cishe ngo-8% kuya ku-10% phakathi; ukumelana kwe-polyolefin kukhula ngokushesha, eminyakeni yamuva nje kuhlale ku-15% kuya ku-20% phakathi, futhi eminyakeni emi-5 kuya kweyishumi ezayo, kungase futhi kulondoloze lesi silinganiso sokukhula.
Isikhathi sokuthunyelwe: Julayi-31-2022