1. Kev Taw Qhia
EVA yog lub npe luv rau ethylene vinyl acetate copolymer, uas yog ib hom polymer polyolefin. Vim nws qhov kub yaj qis, fluidity zoo, polarity thiab non-halogen, nws tuaj yeem sib xws nrog ntau yam polymers thiab minerals hmoov, muaj ntau yam khoom siv kho tshuab thiab lub cev, khoom siv hluav taws xob thiab kev ua haujlwm sib npaug, thiab tus nqi tsis siab, kev muab khoom hauv khw txaus, yog li nws tuaj yeem siv ua cov khoom rwb thaiv tsev cable, kuj tuaj yeem siv ua cov khoom ntim, cov khoom siv sheathing; tuaj yeem ua rau cov khoom siv thermoplastic, thiab tuaj yeem ua rau cov khoom siv thermosetting cross-linking.
EVA muaj ntau yam kev siv, nrog rau cov tshuaj tiv thaiv hluav taws, tuaj yeem ua rau cov pa luam yeeb tsawg lossis cov roj halogen; xaiv EVA uas muaj VA siab ua cov khoom siv hauv paus kuj tseem tuaj yeem ua rau cov khoom siv tiv thaiv roj; xaiv EVA uas muaj cov ntsuas yaj nruab nrab, ntxiv 2 txog 3 zaug ntawm EVA cov tshuaj tiv thaiv hluav taws tuaj yeem ua rau cov txheej txheem extrusion ua tau zoo thiab tus nqi ntawm cov khoom siv oxygen barrier (filling).
Hauv tsab ntawv no, los ntawm cov khoom siv ntawm EVA, kev qhia txog nws daim ntawv thov hauv kev lag luam cable thiab kev cia siab ntawm kev txhim kho.
2. Cov khoom siv ntawm cov qauv
Thaum tsim cov khoom siv synthesis, hloov qhov piv ntawm polymerisation degree n / m tuaj yeem tsim cov ntsiab lus VA ntawm 5 txog 90% ntawm EVA; kev nce tag nrho cov degree polymerisation tuaj yeem tsim qhov hnyav molecular ntawm kaum tawm txhiab txog pua pua txhiab tus EVA; cov ntsiab lus VA hauv qab 40%, vim muaj qhov muaj ib feem ntawm crystallisation, tsis zoo elasticity, feem ntau hu ua EVA yas; thaum cov ntsiab lus VA ntau dua 40%, cov roj hmab zoo li elastomer tsis muaj crystallisation, feem ntau hu ua EVM roj hmab.
1. 2 Cov Khoom Vaj Tse
Cov saw hlau molecular ntawm EVA yog cov qauv linear saturated, yog li nws muaj kev laus zoo thaum tshav kub, huab cua thiab ozone tsis kam.
Cov saw hlau tseem ceeb ntawm EVA tsis muaj ob txoj hlua khi, benzene rings, acyl, amine pawg thiab lwm pawg uas yooj yim haus luam yeeb thaum hlawv, thiab cov saw hlau sab kuj tsis muaj methyl, phenyl, cyano thiab lwm pawg uas yooj yim haus luam yeeb thaum hlawv. Tsis tas li ntawd, cov molecule nws tus kheej tsis muaj cov ntsiab lus halogen, yog li nws tsim nyog rau cov roj tsis muaj pa luam yeeb halogen tsawg.
Qhov loj ntawm cov vinyl acetate (VA) pawg hauv EVA sab saw thiab nws qhov nruab nrab polarity txhais tau tias nws ob qho tib si inhibits qhov kev nyiam ntawm vinyl backbone kom crystallise thiab khub zoo nrog cov mineral fillers, uas tsim cov xwm txheej rau cov roj barrier siab. Qhov no yog qhov tseeb tshwj xeeb rau cov pa luam yeeb tsawg thiab halogen-free resists, raws li flame retardants nrog ntau dua 50% ntim cov ntsiab lus [piv txwv li Al (OH) 3, Mg (OH) 2, thiab lwm yam] yuav tsum tau ntxiv kom ua tau raws li cov kev cai ntawm cable qauv rau flame retardancy. EVA nrog cov ntsiab lus VA nruab nrab mus rau siab yog siv ua lub hauv paus los tsim cov pa luam yeeb tsawg thiab halogen-free flame retardant roj nrog cov khoom zoo heev.
Vim tias EVA sab saw vinyl acetate pawg (VA) yog polar, qhov siab dua VA cov ntsiab lus, qhov ntau polar polymer yog thiab qhov zoo dua qhov tsis kam roj. Qhov tsis kam roj uas kev lag luam cable xav tau feem ntau yog hais txog lub peev xwm los tiv taus cov roj av uas tsis yog polar lossis tsis muaj zog polar. Raws li lub hauv paus ntsiab lus ntawm kev sib raug zoo sib xws, EVA nrog cov ntsiab lus VA siab yog siv ua cov khoom siv hauv paus los tsim cov pa luam yeeb tsawg thiab halogen-dawb roj teeb nrog kev tiv taus roj zoo.
Cov tshuaj EVA hauv alpha-olefin H atom ua haujlwm tau zoo dua, hauv cov peroxide radicals lossis cov electron-radiation muaj zog heev, nws yooj yim rau kev sib txuas H, ua rau cov yas lossis roj hmab sib txuas, thiab tuaj yeem ua rau cov khoom siv hlau thiab cable tshwj xeeb xav tau kev ua haujlwm siab.
Qhov ntxiv ntawm pawg vinyl acetate ua rau qhov kub yaj ntawm EVA poob qis heev, thiab tus lej ntawm VA luv luv sab saw tuaj yeem ua rau EVA ntws nce. Yog li ntawd, nws qhov kev ua tau zoo extrusion zoo dua li cov qauv molecular ntawm cov polyethylene zoo sib xws, dhau los ua cov khoom siv tseem ceeb rau cov ntaub ntawv semi-conductive shielding thiab halogen thiab halogen-free roj barriers.
2 Qhov zoo ntawm cov khoom
2. 1 Kev ua tau zoo heev
Cov khoom siv lub cev thiab lub tshuab ntawm EVA zoo heev, tiv taus kub, tiv taus huab cua, tiv taus ozone, thiab hluav taws xob. Xaiv qib tsim nyog, tuaj yeem ua tau tiv taus kub, tiv taus hluav taws, thiab kuj ua tau roj, thiab cov khoom siv tshwj xeeb uas tiv taus cov kuab tshuaj.
Cov khoom siv thermoplastic EVA feem ntau yog siv nrog cov ntsiab lus VA ntawm 15% txog 46%, nrog rau cov ntsuas yaj ntawm 0.5 txog 4 qib. EVA muaj ntau lub chaw tsim khoom, ntau hom, ntau yam kev xaiv, tus nqi nruab nrab, kev muab khoom txaus, cov neeg siv tsuas yog yuav tsum qhib ntu EVA ntawm lub vev xaib, lub hom, kev ua tau zoo, tus nqi, qhov chaw xa khoom ntawm ib qho kev pom, koj tuaj yeem xaiv, yooj yim heev.
EVA yog ib hom polymer polyolefin, los ntawm kev siv qhov mos mos thiab kev ua tau zoo sib piv, thiab cov khoom siv polyethylene (PE) thiab cov khoom siv cable mos mos polyvinyl chloride (PVC) zoo sib xws. Tab sis kev tshawb fawb ntxiv, koj yuav pom EVA thiab ob hom khoom saum toj no piv rau qhov zoo tshaj plaws.
2. 2 kev ua tau zoo heev
EVA hauv daim ntawv thov cable yog los ntawm cov khoom siv tiv thaiv cable nruab nrab thiab siab voltage sab hauv thiab sab nraud, thiab tom qab ntawd nthuav dav mus rau cov roj tsis muaj halogen. Ob hom khoom no los ntawm qhov pom ntawm kev ua tiav raug suav hais tias yog "cov khoom puv nkaus": cov khoom tiv thaiv vim qhov xav tau ntxiv ntau cov pa roj carbon dub conductive thiab ua rau nws cov viscosity nce, cov kua dej poob qis heev; roj tsis muaj halogen xav tau ntxiv ntau cov nplaim taws retardants, thiab cov khoom tsis muaj halogen viscosity nce siab, cov kua dej poob qis heev. Kev daws teeb meem yog nrhiav cov polymer uas tuaj yeem ntim cov khoom ntim ntau, tab sis kuj muaj viscosity yaj qis thiab fluidity zoo. Vim li no, EVA yog qhov kev xaiv zoo tshaj plaws.
EVA yaj viscosity nrog extrusion ua kub thiab shear tus nqi yuav ua rau kom sai poob, tus neeg siv tsuas yog yuav tsum tau kho qhov kub thiab txias ntawm extruder thiab lub hau ntswj ceev, koj tuaj yeem ua tau zoo heev ntawm cov hlau thiab cable khoom. Muaj ntau daim ntawv thov hauv tsev thiab txawv teb chaws qhia tias, rau cov khoom uas muaj pa luam yeeb tsawg halogen-free, vim tias viscosity loj dhau, cov ntsuas yaj me dhau, yog li tsuas yog siv cov ntsia hlau compression ratio qis (compression ratio tsawg dua 1.3) extrusion, txhawm rau kom ntseeg tau tias extrusion zoo. Cov roj hmab-raws li EVM cov ntaub ntawv nrog cov neeg sawv cev vulcanising tuaj yeem extruded ntawm ob qho tib si roj hmab extruders thiab cov extruders dav dav. Cov txheej txheem vulcanisation (cross-linking) tom qab tuaj yeem ua tiav los ntawm thermochemical (peroxide) cross-linking lossis los ntawm electron accelerator irradiation cross-linking.
2. 3 Yooj yim hloov kho thiab hloov kho
Cov xov hlau thiab cov cables nyob txhua qhov chaw, txij ntawm lub ntuj mus rau hauv av, txij ntawm lub roob mus rau hiav txwv. Cov neeg siv cov xov hlau thiab cov cable xav tau kuj sib txawv thiab txawv, thaum cov qauv ntawm cov xov hlau thiab cov cable zoo sib xws, nws qhov kev ua tau zoo sib txawv feem ntau yog pom hauv cov ntaub ntawv rwb thaiv tsev thiab cov ntaub ntawv npog.
Txog tam sim no, ob qho tib si hauv tsev thiab txawv teb chaws, PVC mos tseem suav rau feem ntau ntawm cov ntaub ntawv polymer siv hauv kev lag luam cable. Txawm li cas los xij, nrog rau kev paub ntau ntxiv txog kev tiv thaiv ib puag ncig thiab kev txhim kho kom ruaj khov.
Cov ntaub ntawv PVC tau raug txwv ntau heev, cov kws tshawb fawb tab tom ua txhua yam kom nrhiav tau lwm cov ntaub ntawv rau PVC, qhov zoo tshaj plaws yog EVA.
EVA tuaj yeem sib xyaw nrog ntau yam polymers, tab sis kuj tseem sib xws nrog ntau yam hmoov av thiab cov khoom siv ua tiav, cov khoom sib xyaw tuaj yeem ua rau cov yas thermoplastic rau cov xov hlau yas, tab sis kuj tseem ua rau cov roj hmab sib txuas rau cov xov hlau roj hmab. Cov neeg tsim qauv tuaj yeem ua raws li tus neeg siv (lossis tus qauv) xav tau, EVA ua cov khoom siv hauv paus, kom ua tau raws li qhov yuav tsum tau ua.
3 EVA daim ntawv thov ntau yam
3. 1 Siv ua cov khoom siv tiv thaiv semi-conductive rau cov xov hluav taws xob siab
Raws li peb txhua tus paub, cov khoom siv tseem ceeb ntawm cov khoom siv tiv thaiv yog cov pa roj carbon dub conductive, hauv cov yas lossis roj hmab cov khoom siv los ntxiv ntau cov pa roj carbon dub yuav ua rau cov khoom siv tiv thaiv thiab qhov du ntawm qib extrusion puas tsuaj. Txhawm rau tiv thaiv kev tso tawm ib nrab hauv cov xov hluav taws xob siab, cov ntaub thaiv sab hauv thiab sab nraud yuav tsum nyias, ci, ci thiab sib xws. Piv rau lwm cov polymers, EVA tuaj yeem ua qhov no yooj yim dua. Qhov laj thawj rau qhov no yog tias EVA cov txheej txheem extrusion yog qhov zoo tshwj xeeb, ntws zoo, thiab tsis yooj yim rau cov xwm txheej yaj tawg. Cov khoom siv tiv thaiv tau muab faib ua ob pawg: qhwv rau hauv tus neeg coj sab nraud hu ua daim ntaub thaiv sab hauv - nrog cov khoom siv sab hauv; qhwv rau hauv cov rwb thaiv tsev sab nraud hu ua daim ntaub thaiv sab nraud - nrog cov khoom siv sab nraud; cov khoom siv sab hauv feem ntau yog thermoplastic Cov khoom siv sab hauv feem ntau yog thermoplastic thiab feem ntau yog raws li EVA nrog cov ntsiab lus VA ntawm 18% txog 28%; cov khoom siv sab nraud feem ntau yog cross-linked thiab peelable thiab feem ntau yog raws li EVA nrog cov ntsiab lus VA ntawm 40% txog 46%.
3. 2 Cov roj thermoplastic thiab cov roj uas tiv taus hluav taws sib txuas
Cov polyolefin thermoplastic uas tiv taus hluav taws kub yog siv dav hauv kev lag luam cable, feem ntau yog rau cov kev xav tau halogen lossis halogen-free ntawm cov cables marine, cov cables fais fab thiab cov kab tsim kho qib siab. Lawv qhov kub ua haujlwm ntev yog txij li 70 txog 90 ° C.
Rau cov xov hluav taws xob nruab nrab thiab siab ntawm 10 kV thiab siab dua, uas muaj qhov yuav tsum tau ua haujlwm hluav taws xob siab heev, cov khoom tiv thaiv hluav taws feem ntau yog ris los ntawm lub plhaub sab nraud. Hauv qee lub tsev lossis cov haujlwm uas xav tau ib puag ncig, cov xov hluav taws xob yuav tsum muaj cov pa luam yeeb tsawg, tsis muaj halogen, tsis muaj tshuaj lom lossis cov pa luam yeeb tsawg thiab cov khoom halogen tsawg, yog li cov thermoplastic flame retardant polyolefins yog cov kev daws teeb meem zoo.
Rau qee lub hom phiaj tshwj xeeb, lub cheeb sab nraud tsis loj, qhov kub thiab txias tsis kam ntawm 105 ~ 150 ℃ ntawm cov cable tshwj xeeb, ntau cov khoom siv hluav taws xob polyolefin uas hla kev sib txuas, nws qhov kev sib txuas tuaj yeem xaiv los ntawm cov chaw tsim khoom cable raws li lawv tus kheej cov xwm txheej tsim khoom, ob qho tib si cov pa roj siab lossis cov dej ntsev kub siab, tab sis kuj muaj electron accelerator chav kub irradiation hla kev sib txuas. Nws qhov kub ua haujlwm ntev yog muab faib ua 105 ℃, 125 ℃, 150 ℃ peb cov ntaub ntawv, cov nroj tsuag tsim khoom tuaj yeem ua raws li cov kev xav tau sib txawv ntawm cov neeg siv lossis cov qauv, halogen-dawb lossis halogen-muaj roj thaiv.
Nws paub zoo tias polyolefins yog cov polymers polar uas tsis yog polar lossis tsis muaj zog polar. Vim tias lawv zoo ib yam li cov roj av hauv polarity, polyolefins feem ntau suav hais tias tsis tshua muaj zog rau roj raws li lub hauv paus ntsiab lus ntawm kev sib xws. Txawm li cas los xij, ntau tus qauv cable hauv tsev thiab txawv teb chaws kuj tau hais tias kev tiv thaiv cross-linked yuav tsum muaj kev tiv thaiv zoo rau roj, cov kuab tshuaj thiab txawm tias rau cov roj slurries, acids thiab alkalis. Qhov no yog qhov nyuaj rau cov kws tshawb fawb cov ntaub ntawv, tam sim no, txawm tias nyob hauv Suav teb lossis txawv teb chaws, cov ntaub ntawv xav tau no tau tsim, thiab nws cov khoom siv hauv paus yog EVA.
3. 3 Cov khoom siv tiv thaiv pa oxygen
Cov xov hlau ntau lub plawv uas muaj hlua khi muaj ntau qhov khoob ntawm cov plawv uas yuav tsum tau sau kom paub tseeb tias cov xov hlau zoo li puag ncig, yog tias qhov sau rau hauv lub plhaub sab nraud yog ua los ntawm cov roj tsis muaj halogen. Cov txheej sau no ua haujlwm ua cov nplaim taws thaiv (oxygen) thaum lub xov hlau hlawv thiab yog li ntawd hu ua "oxygen barrier" hauv kev lag luam.
Cov kev cai yooj yim rau cov khoom siv tiv thaiv pa oxygen yog: cov khoom extrusion zoo, cov nplaim taws tsis muaj halogen zoo (cov pa oxygen feem ntau siab dua 40) thiab tus nqi qis.
Cov pa oxygen barrier no tau siv dav hauv kev lag luam cable tau ntau tshaj kaum xyoo thiab tau ua rau muaj kev txhim kho zoo hauv kev tiv thaiv hluav taws ntawm cov cables. Cov pa oxygen barrier no siv tau rau ob qho tib si halogen-free flame-retardant cables thiab halogen-free flame-retardant cables (piv txwv li PVC). Kev xyaum ntau tau qhia tias cov cables uas muaj oxygen barrier yuav dhau qhov kev sim hlawv ib zaug thiab kev sim hlawv ua ke.
Los ntawm qhov pom ntawm cov khoom siv tsim, cov khoom siv oxygen barrier no yog "ultra-high filler", vim tias kom tau raws li tus nqi qis, nws yog qhov tsim nyog siv cov khoom siv filler siab, kom ua tiav cov pa oxygen siab yuav tsum ntxiv qhov feem pua siab (2 txog 3 zaug) ntawm Mg (OH) 2 lossis Al (OH) 3, thiab kom extrude zoo thiab yuav tsum xaiv EVA ua cov khoom siv hauv paus.
3. 4 Cov khoom siv PE sheathing hloov kho
Cov ntaub ntawv polyethylene sheathing muaj ob qhov teeb meem: thawj zaug, lawv muaj feem yuav yaj tawg (piv txwv li daim tawv nqaij ntses) thaum lub sijhawm extrusion; qhov thib ob, lawv muaj feem yuav tawg vim muaj kev ntxhov siab ntawm ib puag ncig. Qhov kev daws teeb meem yooj yim tshaj plaws yog ntxiv qee qhov feem ntawm EVA rau hauv cov qauv. Siv ua EVA hloov kho feem ntau siv cov ntsiab lus VA qis ntawm qib, nws cov ntsuas yaj rau ntawm 1 txog 2 yog qhov tsim nyog.
4. Kev cia siab rau kev loj hlob
(1) EVA tau siv dav hauv kev lag luam cable, qhov nyiaj txhua xyoo hauv kev loj hlob maj mam thiab ruaj khov. Tshwj xeeb tshaj yog nyob rau hauv kaum xyoo dhau los, vim qhov tseem ceeb ntawm kev tiv thaiv ib puag ncig, EVA-raws li roj tsis kam tau loj hlob sai, thiab tau hloov ib feem ntawm PVC-raws li cov khoom siv cable. Nws cov nqi ua tau zoo heev thiab kev ua tau zoo heev ntawm cov txheej txheem extrusion yog qhov nyuaj rau hloov lwm yam khoom siv.
(2) Kev lag luam cable siv EVA resin txhua xyoo ze li ntawm 100,000 tons, kev xaiv ntawm EVA resin ntau yam, VA cov ntsiab lus los ntawm qis mus rau siab yuav siv, ua ke nrog cov khoom siv cable granulation loj ntawm lub tuam txhab tsis loj, kis tau hauv txhua lub tuam txhab txhua xyoo tsuas yog hauv ntau txhiab tons ntawm EVA resin nce thiab nqis, yog li yuav tsis yog EVA kev lag luam loj saib xyuas. Piv txwv li, qhov ntau tshaj plaws ntawm cov khoom siv hluav taws xob tsis muaj halogen, qhov kev xaiv tseem ceeb ntawm VA / MI = 28 / 2 ~ 3 ntawm EVA resin (xws li US DuPont's EVA 265 #). Thiab qhov kev qhia tshwj xeeb no ntawm EVA txog tam sim no tsis muaj cov chaw tsim khoom hauv tsev los tsim thiab muab khoom. Tsis tas li ntawd, VA cov ntsiab lus siab dua 28, thiab cov ntsuas yaj tsawg dua 3 ntawm lwm cov EVA resin tsim thiab muab khoom.
(3) cov tuam txhab txawv teb chaws tsim EVA vim tsis muaj cov neeg sib tw hauv tsev, thiab tus nqi tau ntev siab, ua rau lub Hoobkas cable hauv tsev tsis txaus siab rau kev tsim khoom. Ntau tshaj 50% ntawm cov roj hmab EVM uas muaj VA, yog cov tuam txhab txawv teb chaws tswj hwm, thiab tus nqi zoo ib yam li cov roj hmab EVM 2 txog 3 zaug. Cov nqi siab zoo li no, kuj cuam tshuam rau qhov ntau ntawm cov roj hmab EVM no, yog li kev lag luam cable hu rau cov tuam txhab tsim khoom EVA hauv tsev, kom txhim kho tus nqi ntawm kev tsim khoom hauv tsev ntawm EVA. Kev tsim khoom ntau ntxiv ntawm kev lag luam tau siv EVA resin ntau heev.
(4) Nyob rau hauv lub caij nyoog ntawm kev lag luam thoob ntiaj teb, EVA raug suav hais tias yog cov khoom siv zoo tshaj plaws rau kev tiv thaiv roj av uas tsis ua rau ib puag ncig puas tsuaj. Kev siv EVA loj hlob ntawm tus nqi ntawm 15% ib xyoos thiab qhov kev cia siab zoo heev. Tus nqi thiab kev loj hlob ntawm cov ntaub ntawv tiv thaiv thiab cov xov hluav taws xob nruab nrab thiab siab thiab kev loj hlob ntawm cov khoom siv hluav taws xob, kwv yees li 8% txog 10% ntawm; polyolefin resistances tab tom loj hlob sai, nyob rau xyoo tas los no tseem nyob ntawm 15% txog 20% ntawm, thiab hauv 5 txog 10 xyoo tom ntej, kuj tseem yuav tswj tau tus nqi loj hlob no.
Lub sijhawm tshaj tawm: Lub Xya Hli-31-2022