1. Intshayelelo
I-EVA sisifinyezo se-ethylene vinyl acetate copolymer, i-polyolefin polymer. Ngenxa yobushushu bayo obuphantsi bokunyibilika, ukunyibilika okuhle, i-polarity kunye nezinto ezingezizo ze-halogen, kwaye inokuhambelana neentlobo ngeentlobo zeepolymers kunye neepowders zeminerali, inani leempawu zoomatshini kunye nezomzimba, iimpawu zombane kunye nokulinganisela kokusebenza kokucubungula, kwaye ixabiso aliphezulu, ukubonelela ngemarike kwanele, ngoko zombini njengezinto zokukhusela intambo, zingasetyenziswa njengezinto zokugcwalisa, izinto zokubeka isigqubuthelo; zingenziwa ngezinto ze-thermoplastic, kwaye zingenziwa ngezinto zokudibanisa i-thermosetting.
Iindlela ezahlukeneyo zokusetyenziswa ze-EVA, ezine-flame retardants, zinokwenziwa zibe yi-halogen-free okanye i-halogen fuel barrier ephantsi; khetha umxholo ophezulu we-VA we-EVA njengoko izinto ezisisiseko zingenziwa zibe zizinto ezimelana neoyile; khetha i-melt index ye-EVA ephakathi, yongeza amaxesha ama-2 ukuya kwama-3 ukuzaliswa kwe-EVA flame retardants kunokwenziwa ukuze inkqubo yokukhupha ikwazi ukusebenza kunye nexabiso lezinto ezithintela ioksijini (ukuzalisa) ezilungeleleneyo.
Kule phepha, ukusuka kwiimpawu zesakhiwo se-EVA, ukuqaliswa kokusetyenziswa kwayo kushishino lweentambo kunye namathuba ophuhliso.
2. Iimpawu zesakhiwo
Xa kuveliswa i-synthesis, ukutshintsha umlinganiselo we-polymerisation degree n/m kunokuvelisa umxholo we-VA ukusuka kwi-5 ukuya kwi-90% ye-EVA; ukwandisa i-total polymerisation degree kunokuvelisa ubunzima be-molecular ukusuka kumashumi amawaka ukuya kumakhulu amawaka e-EVA; umxholo we-VA ungaphantsi kwe-40%, ngenxa yokubakho kwe-crystallisation engaphelelanga, ukuthamba okungekuhle, okwaziwa ngokuba yi-EVA plastic; xa umxholo we-VA ungaphezulu kwe-40%, i-elastomer efana nerabha engena-crystallisation, yaziwa ngokuba yi-EVM rubber.
1. 2 Iipropati
Ikhonkco le-molecular ye-EVA liyilayini egcweleyo, ngoko ke inokuguga kakuhle kobushushu, imozulu kunye nokumelana ne-ozone.
Itsheyini ephambili yemolekyuli ye-EVA ayinazo iibhondi eziphindwe kabini, indandatho yebenzene, i-acyl, amaqela e-amine kunye namanye amaqela okulula ukuwatshaya xa kutsha, iitsheyini ezisecaleni nazo azinazo i-methyl, i-phenyl, i-cyano kunye namanye amaqela. Ukongeza, imolekyuli ngokwayo ayinazo izinto ze-halogen, ngoko ke ifanelekile ngakumbi kwisiseko sepetroli esingenamsi uphantsi se-halogen.
Ubukhulu obukhulu beqela le-vinyl acetate (VA) kwi-side chain ye-EVA kunye ne-medium polarity yayo kuthetha ukuba zombini ezi zinto zithintela ukuthambekela komqolo we-vinyl ukuba uqine kwaye zihambelane kakuhle nezizalisi zezimbiwa, nto leyo edala iimeko zamafutha okuthintela ukusebenza okuphezulu. Oku kuyinyani ngakumbi kwi-smoke ephantsi kunye ne-halogen-free resists, njengoko ii-flame retardants ezinomxholo wevolumu engaphezulu kwe-50% [umz. Al(OH) 3, Mg(OH) 2, njl.njl.] kufuneka zongezwe ukuze kuhlangatyezwane neemfuno zemigangatho yekhebula ye-flame retardant. I-EVA enomxholo we-VA ophakathi ukuya phezulu isetyenziswa njengesiseko ukuvelisa amafutha okuthintela ilangatye aphantsi kunye ne-halogen-free aneempawu ezintle.
Njengoko iqela le-vinyl acetate ye-EVA esecaleni likwi-polar, okukhona umxholo we-VA uphezulu, kokukhona i-polymer ikwi-polar kwaye kokukhona ukumelana neoyile kuphucuka. Ukumelana neoyile okufunekayo kushishino lweentambo kubhekisa kakhulu kubuchule bokumelana neeoyile zeminerali ezingezizo ze-polar okanye ze-polar ezibuthathaka. Ngokomgaqo wokuhambelana okufanayo, i-EVA enomxholo ophezulu we-VA isetyenziswa njengesixhobo esisisiseko ukuvelisa umqobo wamafutha ophantsi kunye ne-halogen ongenawo umsi kunye nokumelana neoyile okuhle.
Iimolekyuli ze-EVA kwi-alpha-olefin H atom ukusebenza kuyasebenza ngakumbi, kwi-peroxide radicals okanye kwi-high-energy electron-radiation effect kulula ukuyithatha i-H cross-linking reaction, ibe yiplastiki edibeneyo okanye irabha, ingenziwa imfuneko yokusebenza efunekayo yezixhobo ezikhethekileyo zentambo kunye neentambo.
Ukongezwa kweqela le-vinyl acetate kwenza ubushushu bokunyibilika kwe-EVA bunciphe kakhulu, kwaye inani lee-VA short side chains lingenza ukuhamba kwe-EVA kwande. Ke ngoko, ukusebenza kwayo kwe-extrusion kungcono kakhulu kunesakhiwo se-molecular se-polyethylene efanayo, ibe yinto ekhethwayo kwizixhobo zokukhusela ezisebenzisa i-semi-conductive kunye nezithintelo ze-halogen kunye ne-halogen-free fuel.
2 Iingenelo zemveliso
2. 1 Ukusebenza ngexabiso eliphezulu kakhulu
Iimpawu zomzimba nezoomatshini ze-EVA, ukumelana nobushushu, ukumelana nemozulu, ukumelana ne-ozone, iimpawu zombane zilungile kakhulu. Khetha uhlobo olufanelekileyo, ungenza ukumelana nobushushu, ukusebenza okubambezela ilangatye, kodwa kunye neoyile, izixhobo ezikhethekileyo zekhebula ezinganyangekiyo kwisinyibilikisi.
Izinto ze-EVA ze-thermoplastic zisetyenziswa kakhulu ngomxholo we-VA ophakathi kwe-15% ukuya kwi-46%, kunye ne-melt index ye-0.5 ukuya kwi-4 grades. I-EVA inabavelisi abaninzi, iimpawu ezininzi, uluhlu olubanzi lweendlela, amaxabiso aphakathi, unikezelo olufanelekileyo, abasebenzisi bafuna kuphela ukuvula icandelo le-EVA kwiwebhusayithi, uphawu, ukusebenza, ixabiso, indawo yokuhambisa ngokujonga nje, ungakhetha, kulula kakhulu.
I-EVA yi-polyolefin polymer, ngenxa yokuthamba nokusetyenziswa kokuthelekiswa kokusebenza, kwaye izinto ze-polyethylene (PE) kunye nezinto zekhebula ze-polyvinyl chloride (PVC) ezithambileyo ziyafana. Kodwa uphando olongezelelweyo, uza kufumana i-EVA kunye neentlobo ezimbini zezinto ezingentla xa kuthelekiswa nomgangatho ongenakutshintshwa.
2. 2 ukusebenza kakuhle kakhulu kokucubungula
I-EVA kwisicelo sentambo ivela kwizinto zokukhusela intambo ezisebenzisa umbane ophakathi nophezulu ngaphakathi nangaphandle ekuqaleni, kwaye kamva zandiswa ukuya kwisithintelo sepetroli esingena-halogen. Ezi ntlobo zimbini zezinto ngokwembono yokucubungula zithathwa njengezinto "ezizaliswe kakhulu": izinto zokukhusela ngenxa yesidingo sokongeza inani elikhulu le-carbon black eqhubayo kwaye zenze i-viscosity yayo inyuke, ulwelo lwehle kakhulu; i-halogen-free flame retardant fuel kufuneka yongezwe inani elikhulu le-halogen-free flame retardants, kunye ne-halogen-free material viscosity inyuke kakhulu, ulwelo lwehle kakhulu. Isisombululo kukufumana i-polymer enokwamkela iidosi ezinkulu ze-filler, kodwa ikwanayo ne-viscosity ephantsi yokunyibilika kunye nolwelo oluhle. Ngenxa yesi sizathu, i-EVA lukhetho olukhethwayo.
I-EVA melt viscosity enobushushu bokucubungula i-extrusion kunye nesantya sokucheba iya kunyusa ukwehla ngokukhawuleza, umsebenzisi kufuneka alungise ubushushu be-extruder kunye nesantya sesikrufu, ungenza ukusebenza okuhle kakhulu kweemveliso zentambo kunye neentambo. Inani elikhulu lezicelo zasekhaya nezangaphandle zibonisa ukuba, kwizinto ezingenayo i-halogen yomsi ezaliswe kakhulu, kuba i-viscosity inkulu kakhulu, i-melt index incinci kakhulu, ngoko ke ukusetyenziswa kwe-low compression ratio screw (compression ratio engaphantsi kwe-1.3) extrusion kuphela, ukuqinisekisa umgangatho olungileyo we-extrusion. Izixhobo ze-EVM ezisekwe kwirabha ezinee-agents ze-vulcanising zinokukhutshelwa kuzo zombini ii-raber extruders kunye nee-general purpose extruders. Inkqubo elandelayo ye-vulcanisation (cross-linking) inokwenziwa nokuba yi-thermochemical (peroxide) cross-linking okanye nge-electron accelerator irradiation cross-linking.
2. 3 Kulula ukuyitshintsha nokuyilungisa
Iingcingo kunye neentambo zikho kuyo yonke indawo, ukusuka esibhakabhakeni ukuya emhlabeni, ukusuka ezintabeni ukuya elwandle. Abasebenzisi beemfuno zengcingo kunye neentambo nabo bayahluka kwaye bangaqhelekanga, ngelixa ulwakhiwo lwengcingo kunye neentambo lufana, umahluko wokusebenza kwayo ubonakala kakhulu kwizinto zokugquma kunye ne-sheath.
Okwangoku, ekhaya nakwamanye amazwe, i-PVC ethambileyo isasebenza kakhulu kwizixhobo zepolymer ezisetyenziswa kushishino lweentambo. Nangona kunjalo, ngenxa yokwanda kolwazi malunga nokukhuselwa kwendalo kunye nophuhliso oluzinzileyo.
Izinto zePVC zithintelwe kakhulu, izazinzulu zenza konke okusemandleni azo ukufumana ezinye izinto endaweni yePVC, eyona ithembisayo kuzo yi-EVA.
I-EVA ingaxutywa nee-polymers ezahlukeneyo, kodwa kunye neendidi ezahlukeneyo zeepowders zeminerali kunye nezixhobo zokucubungula ezihambelanayo, iimveliso ezixutyiweyo zingenziwa iplastiki ye-thermoplastic kwiintambo zeplastiki, kodwa zenziwe irabha edibeneyo kwiintambo zerabha. Abayili befomyula banokusekelwe kwiimfuno zomsebenzisi (okanye ezisemgangathweni), i-EVA njengesixhobo esisisiseko, ukwenza ukusebenza kwento kuhambelane neemfuno.
Uluhlu lwesicelo se-EVA olu-3
3. 1 Isetyenziswa njengesixhobo sokukhusela esisebenza ngombane esingenamthungo kwiintambo zamandla ezine-voltage ephezulu
Njengoko sonke sisazi, izinto eziphambili zezinto zokukhusela yi-conductive carbon black, kwiplastiki okanye kwisiseko serabha ukuze kongezwe inani elikhulu le-carbon black kuya konakalisa kakhulu ukugeleza kwezinto zokukhusela kunye nokuthamba kwenqanaba lokukhupha. Ukuthintela ukukhutshwa okungaphelelanga kwiintambo ze-voltage ephezulu, izikhuselo zangaphakathi nezangaphandle kufuneka zibe zincinci, zikhazimle, zikhanye kwaye zifane. Xa kuthelekiswa nezinye iipolymers, i-EVA ingakwenza oku ngokulula. Isizathu soku kukuba inkqubo yokukhupha i-EVA ilungile kakhulu, ihamba kakuhle, kwaye ayithambekeli ekuqhekekeni. Izinto zokukhusela zahlulwe zibe ziindidi ezimbini: zisongelwe kwi-conductor ngaphandle ebizwa ngokuba yi-inner shield - ngezinto zesikrini sangaphakathi; zisongelwe kwi-insulation ngaphandle ebizwa ngokuba yi-outer shield - ngezinto zesikrini sangaphandle; izinto zesikrini sangaphakathi ikakhulu ziyi-thermoplastic. Izinto zesikrini sangaphakathi ikakhulu ziyi-thermoplastic kwaye zihlala zisekelwe kwi-EVA enomxholo we-VA we-18% ukuya kwi-28%; izinto zesikrini sangaphandle zihlala ziqhagamshelwe kwaye ziyaxobuka kwaye zihlala zisekelwe kwi-EVA enomxholo we-VA we-40% ukuya kwi-46%.
3. 2 Amafutha athintela ilangatye asebenzisa i-thermoplastic kunye nalawo adityaniswe ne-cross-linked flame retardant fuels
I-polyolefin ethintela ilangatye ye-thermoplastic isetyenziswa kakhulu kushishino lweentambo, ikakhulu kwiimfuno ze-halogen okanye i-halogen kwiintambo zaselwandle, iintambo zombane kunye nemigca yokwakha yodidi oluphezulu. Amaqondo obushushu azo okusebenza ixesha elide aqala kwi-70 ukuya kwi-90 °C.
Kwiintambo zamandla ezisebenza ngombane eziphakathi neziphezulu ze-10 kV nangaphezulu, ezineemfuno eziphezulu kakhulu zokusebenza kombane, iipropati zokurhoxisa ilangatye zithwalwa kakhulu yi-external sheath. Kwezinye izakhiwo okanye iiprojekthi ezifuna indalo esingqongileyo, iintambo kufuneka zibe nomsi omncinci, ezingenayo i-halogen, ezinobuthi obuphantsi okanye umsi omncinci kunye neepropati ze-halogen ephantsi, ngoko ke iipolyolefins ezirhoxisa ilangatye ezisebenzisa i-thermoplastic zisisombululo esisebenzayo.
Ngeenjongo ezithile ezikhethekileyo, ububanzi bangaphandle abubukhulu, ukumelana nobushushu kwi-105 ~ 150 ℃ phakathi kwentambo ekhethekileyo, izinto ze-polyolefin ezithintela ilangatye ezidityanisiweyo ngakumbi, uqhagamshelo lwayo lunokukhethwa ngumvelisi wentambo ngokweemeko zabo zemveliso, zombini umphunga wendabuko oxinzelelweyo ophezulu okanye ubhavu wetyuwa obushushu obuphezulu, kodwa ikwafumaneka ne-electron accelerator room temperature irradiation cross-linked way. Ubushushu bayo bokusebenza bexesha elide bahlulwe baba yi-105 ℃, 125 ℃, 150 ℃ iifayile ezintathu, isityalo semveliso singenziwa ngokweemfuno ezahlukeneyo zabasebenzisi okanye imigangatho, umqobo wamafutha ongenayo i-halogen okanye i-halogen.
Kuyaziwa ukuba iipolyolefins ziipolymers ezingezizo iipolar okanye ezibuthathaka. Njengoko zifana neoyile yeminerali kwi-polarity, iipolyolefins zithathwa njengezingaxhathisi kakhulu kwioyile ngokomgaqo wokuhambelana okufanayo. Nangona kunjalo, imigangatho emininzi yeentambo ekhaya nakwamanye amazwe ikwachaza ukuba ukumelana okunxibeleleneyo kufuneka kube nokuxhathisa okuhle kwioyile, izinyibilikisi kwanakwi-slurry yeoyile, ii-asidi kunye nee-alkali. Lo ngumceli mngeni kubaphandi bezinto eziphathekayo, ngoku, nokuba kuseTshayina okanye kwamanye amazwe, ezi zinto zinzima ziye zaphuhliswa, kwaye izinto ezisisiseko ziyi-EVA.
3. 3 Izinto ezithintela ioksijini
Iintambo ezixineneyo ezinee-core ezininzi zineendawo ezininzi phakathi kwee-cores ekufuneka zizaliswe ukuqinisekisa ukubonakala kwentambo ejikelezileyo, ukuba ukuzaliswa ngaphakathi kwesheath yangaphandle kwenziwe ngesithintelo samafutha esingena-halogen. Olu layer lokuzalisa lusebenza njengesithintelo selangatye (i-oksijini) xa intambo itsha kwaye ke ngoko yaziwa ngokuba “sisithintelo se-oksijini” kushishino.
Iimfuno ezisisiseko zezinto ezithintela ioksijini zezi: iipropati ezilungileyo zokukhupha umoya, ukubambezeleka komlilo okungenalo i-halogen (isalathisi seoksijini sidla ngokuba ngaphezulu kwama-40) kunye nexabiso eliphantsi.
Esi sithintelo seoksijini sisetyenziswe kakhulu kwishishini leentambo kangangeminyaka engaphezu kweshumi kwaye sikhokelele ekuphuculeni okukhulu ekuthintelweni komlilo kweentambo. Isithintelo seoksijini singasetyenziselwa zombini iintambo ezithintela umlilo ezingenayo i-halogen kunye neentambo ezithintela umlilo ezingenayo i-halogen (umz. i-PVC). Uqheliso oluninzi lubonise ukuba iintambo ezinesithintelo seoksijini zinokwenzeka ukuba ziphumelele uvavanyo olunye lokutsha ngokuthe nkqo kunye nokutshisa ngebhanti.
Ngokwembono yokwenziwa kwezinto, le nto yokuthintela ioksijini ngokwenene "yi-filler ephezulu kakhulu", kuba ukuze kuhlangatyezwane nexabiso eliphantsi, kuyimfuneko ukusebenzisa i-filler ephezulu, ukuze kufezekiswe i-oxygen index ephezulu kufuneka wongeze inani eliphezulu (ka-2 ukuya ku-3) le-Mg (OH) 2 okanye i-Al (OH) 3, kwaye ukuze kukhutshwe okulungileyo kufuneka ukhethe i-EVA njengezinto ezisisiseko.
3. 4 Izinto eziguquliweyo ze-PE sheathing
Izinto zokugquma i-polyethylene zinokuba neengxaki ezimbini: okokuqala, zinokuba nokuqhekeka kokunyibilika (oko kukuthi, isikhumba se-sharkskin) ngexesha lokukhutshelwa ngaphandle; okwesibini, zinokuba nokuqhekeka koxinzelelo lokusingqongileyo. Isisombululo esilula kukongeza umlinganiselo othile we-EVA kwifomyula. Isetyenziswa njenge-EVA eguquliweyo ikakhulu kusetyenziswa umxholo we-VA ophantsi wenqanaba, i-melt index yayo ukuya phakathi kwe-1 ukuya kwi-2 ifanelekile.
4. Amathuba ophuhliso
(1) I-EVA isetyenziswa kakhulu kushishino lweentambo, isixa sonyaka ekukhuleni kancinci nangokuzinzileyo. Ingakumbi kwiminyaka elishumi edlulileyo, ngenxa yokubaluleka kokukhuselwa kwendalo, ukumelana nepetroli esekwe kwi-EVA kuye kwaba luphuhliso olukhawulezileyo, kwaye ngokuyinxenye ithathe indawo yendlela yezixhobo zentambo esekwe kwi-PVC. Ukusebenza kwayo kakuhle kweendleko kunye nokusebenza kakuhle kwenkqubo yokukhupha kunzima ukutshintsha naziphi na ezinye izinto.
(2) ukusetyenziswa konyaka kwe-EVA resin kushishino lweentambo kufutshane neetoni ezili-100,000, ukhetho lweentlobo ze-EVA resin, umxholo we-VA ukusuka ezantsi ukuya phezulu uya kusetyenziswa, kunye nezinto zentambo ubungakanani beshishini abubukhulu, busasazeka kwishishini ngalinye minyaka le kuphela kumawaka eetoni ze-EVA resin phezulu nasezantsi, kwaye ngaloo ndlela akuyi kuba yingqwalasela enkulu kwishishini le-EVA. Umzekelo, inani elikhulu lezinto ezisisiseko ze-halogen-free flame retardant, ukhetho oluphambili lwe-VA / MI = 28 /2 ~ 3 ye-EVA resin (njenge-US DuPont's EVA 265 #). Kwaye olu didi lweenkcukacha ze-EVA ukuza kuthi ga ngoku akukho bavelisi basekhaya bokuvelisa nokubonelela. Ingasathethwa ke umxholo we-VA ongaphezulu kwama-28, kwaye i-index ye-melt engaphantsi kwama-3 yezinye iimveliso ze-EVA resin kunye nokubonelela.
(3) iinkampani zangaphandle ezivelisa i-EVA ngenxa yokuba kungekho baphikisi basekhaya, kwaye ixabiso beliphezulu ixesha elide, licinezela kakhulu umdla wokuveliswa kwezityalo zekhebula zasekhaya. Ngaphezulu kwe-50% yomxholo we-VA we-EVM yohlobo lwerabha, yinkampani yangaphandle elawulwayo, kwaye ixabiso lifana nomxholo we-VA wophawu izihlandlo ezi-2 ukuya kwezi-3. Amaxabiso aphezulu anjalo, nawo, achaphazela ubungakanani bolu hlobo lwerabha lwe-EVM, ngoko ke ishishini leentambo lifuna abavelisi be-EVA basekhaya, ukuba baphucule izinga lemveliso yasekhaya ye-EVA. Imveliso engaphezulu yoshishino ibisoloko isetyenziswa kakhulu yi-resin ye-EVA.
(4) Ixhomekeke kwiliza lokhuseleko lokusingqongileyo kwixesha lehlabathi, i-EVA ithathwa lishishini leentambo njengeyona nto iphambili yokumelana nepetroli enobuhlobo nokusingqongileyo. Ukusetyenziswa kwe-EVA kukhula ngesantya se-15% ngonyaka kwaye imbonakalo ithembisa kakhulu. Ubungakanani kunye nesantya sokukhula kwezinto zokukhusela kunye nemveliso yekhebula lamandla aphakathi naphezulu kunye nesantya sokukhula, malunga ne-8% ukuya kwi-10% phakathi; ukumelana kwe-polyolefin kukhula ngokukhawuleza, kwiminyaka yakutshanje kuhlale kwi-15% ukuya kwi-20% phakathi, kwaye kwiminyaka emi-5 ukuya kwe-10 ezayo, nayo inokugcina esi santya sokukhula.
Ixesha lokuthumela: Julayi-31-2022