Cov txheej txheem ntau lawm ntawm PET daim ntawv
(1) Cov khoom nyoos ntawm PET ntawv
Zoo li lwm yam plastics, PET daim ntawv ua tau zoo yog ze rau cov phaus molecular. Intrinsic viscosity txiav txim qhov hnyav phaus. Qhov ntau dua ntawm kev nkag siab lub cev, qhov zoo dua ntawm cov khoom siv lub cev thiab tshuaj, tab sis cov lus tsis zoo ua rau molding nyuaj. Tsawg dua ntawm kev nkag siab viscosity, lub zog tsis zoo nws lub cev thiab tshuaj zog thiab cuam tshuam lub zog. Yog li ntawd, qhov tseem ceeb viscosity ntawm PET pob tshab ntawv yuav tsum yog 0.8dl / g-0.9dl / g.
(2) Cov txheej txheem ntau lawm.
Cov cuab yeej tseem ceeb ntawm PET pob tshab yog: crystallization ntauwd, kom qhuav ntauwd, txuas ntxiv, tuag lub taub hau, peb-yob calender, thiab coiler.
Cov txheej txheem ntau lawm yog: raw cov khoom siv crystallization-ziab-extrusion yasization-extrusion molding-
Calendering thiab shaping ib qho los ntawm ib qho khoom siv cua.
Thawj kaujruam yog muaju tawm. Cov PET cov nplais yog qhov ua kom kub siab thiab quaj rau hauv cov hluav taws xob crystallization los ua cov lwg me me tau teeb tsa kom zoo, thiab tom qab ntawd lub khob hloov kub ntawm cov nplais tau nce. Lub hom phiaj yog los tiv thaiv kev nplaum rau lub sijhawm kom qhuav thiab thaiv lub plhaw. Crystallization feem ntau yog kauj ruam uas tsis tseem ceeb. Lub crystallization siv sijhawm 30 feeb rau 90 feeb thiab qhov kub tsis txias tshaj 149°C.
Qhov thib ob kauj ruam yog ziab. Nyob hauv qhov kub thiab txias, dej yuav ua rau hydrolytic degradation ntawm PET, ua rau nws txo qis ntawm nws cov xeeb ceem, thiab nws lub cev muaj zog, tshwj xeeb tshaj yog cuam tshuam lub zog, yuav txo nrog qhov txo qis ntawm lub cev molecular. Yog li no, PET yuav tsum tau qhuav ua ntej yaj thiab rho tawm kom txo cov dej noo, thiab nws cov ntsiab lus noo yuav tsum tsawg dua 0.005%. Lub tshuab ziab khaub ncaws siv lub tshuab ziab khaub ncaws desiccant. Vim yog hygroscopicity ntawm cov khoom PET, cov ntawv cog lus molecular yuav tsim thaum ya raws nkag mus rau saum npoo ntawm cov hlais. Lwm qhov ntawm ya raws yuav muaj nyob tob hauv cov hlais, uas yuav ua rau kom muaj teeb meem qhuav. Yog li ntawv, cov cua kub tsis zoo siv tsis tau. Cov huab cua kub lwg taw tes yuav tsum qis dua-40 C, thiab cov cua kub kis mus rau hauv lub plhaw-plhaw los ntawm lub voj kev kaw kom tsis tu ncua kom qhuav.
Qhov thib peb kauj ruam yog extrusion molding. Tom qab crystallization thiab qhuav, PET yog hloov mus rau hauv cov siab polymer nrog pom tseeb melting kis. Kev txhaj tshuaj molding kub ntawm polymer siab yog siab thiab qhov ntsuas kub tswj qhov nqaim yog nqaim. Lub hau ntswj ntsia hlau tshwj xeeb yog siv rau polyester yog siv los cais cov ntoo tsis qab thiab yaj, uas pab tswj cov txheej txheem kev txiav ntev dua thiab nce cov khoom tsim tawm ntawm cov extruder. Siv ua lub ntsej muag tuag lub taub hau yooj yim nrog lub kwj nrig baffle. Lub taub hau yog ntawm lub ntsej muag zoo tib yam. Lub chaw khiav ceev ntws thiab tsis-khawb tuag daim di ncauj qhia qhov ua tiav zoo. Rhaub ntawm lub taub hau muaj qhov haujlwm ntawm dej xau thiab tu. Kev tuag daim di ncauj yuav tsum ua kom muaj kev sib koom tes zoo, thiab cov teeb tsa ua lub ntsej muag tuag ntawm lub taub hau ncaj qha cuam tshuam rau sab hauv cov xim sib txawv ntawm cov ntawv thiab lub tiaj ntawm calendering. Thaum extruded rau hauv ib daim ntawv, qhov kub sib nug xov mus rau sab xub ntiag thaj tsam ntawmLub fuselage, nruab nrab thaj tsam ntawmLub fuselage, lub qab qhov chaw ntawmtus fuselage, lub vijtsam hloov pauv, thiab lub qhov ntswg ntawm lub fuselage yog 240°C-260°C, 265°C-275°C, thiab 260°C-265°C ntsig txog. , 260°C-265°C, 255°C-265°C.
Kauj ruam plaub yog kom txias thiab duab. Tom qab lub yaj yaj los ntawm lub tshuab taub hau, nws ncaj qha nkag rau hauv peb-yob calender rau calendering thiab txias. Qhov kev ncua deb ntawm peb-yob calender thiab lub taub hau tshuab feem ntau khaws cia txog li 8cm, vim tias qhov kev ncua deb loj heev, cov ntawv zoo li yuav sag thiab crease, Ua rau tsis zoo du ntawm daim ntawv, ntxiv rau, vim yog ntev li ntawm deb, qhov kev tshem tawm cov cua sov thiab cua txias yog ib yam nkaus thiab qeeb, thiab cov siv lead ua ntxuav hniav dawb tshwm sim, uas tsis zoo rau kev calendering. Qhov peb-yob calender tsev muaj peb lub yob tawm, lub siab dua, nruab nrab thiab qis qis dua. Lub axis ntawm nruab nrab ntawm cov menyuam yog tsau. Thaum lub caij txias thiab calendering, qhov kub ntawm cov menyuam cov nplaim yog 40°C-50°C. Lub axis ntawm sab saud thiab qis dua tuaj yeem txav mus thiab nce. Lub axis txav nce thiab nqis los kho qhov sib txawv ntawm cov menyuam. Qhov kub ntawm cov dov sab saud thiab qis dua yog 30°C-60 C thiab 52°C-68°C. Peb tus dov yuav tsum xyuas kom meej tias lub nrawm tau sib hloov, thiab qhov nrawm yuav tsum siab tshaj qhov nqi rho tawm. Lub hom phiaj yog txhawm rau Thaum cov khoom yoojyim tawm qhov tuag, nws nthuav tawm thiab ua kom lub zog sab hauv los ntawm daim ntawv, ua rau cov ntaub qhwv ntsej muag ploj. Tsiaj yuav crystallize nyob rau hauv thaj tsam ntawm 100°C-250°C, thiab tus lej crystallization yog 140°C-180°C Thaum cov khoom siv crystallization ceev tau nrawm dua, yog li cov crystallization tuaj yeem ua tiav hauv ob peb feeb. PET xav tau kom dhau nrawm ntawm qhov chaw crystallization qhov kub thiab txias thiab tswj nruj qhov kub ntawm peb yob.
Kauj ruam thib tsib yog kev sib tseb thiab cua. Daim ntawv tawm los ntawm lub calender roller thiab nkag mus rau hauv lub ntaus ntaus los ntawm phau ntawv qhia rau cov menyuam. Cov cuab yeej siv khov kho muaj cov roj hmab txav ua haujlwm thiab cov roj hmab passive. Cov cua ntsig nias ob chav yob feem ntau tiv thaiv daim ntawv cov khoom los ntawm kev rub rau cov khoom siv winding los ntawm ob lub yob txhawm rau tsim cov ntawv ua kom tsis muaj zog.
Cov teeb meem muaj txiaj ntsig zoo hauv kev tsim cov PET pob tshab thiab lawv cov kev daws teeb meem
(1) Cov ntawv ntim khoom ua rau siv lead ua point impurities. Cov laj thawj rau qhov no yog cov khoom siv ua raw khoom thiab tshuaj cais tawv. PET chip nws tus kheej tsis tsim cov siv lead ua kom tsis muaj zog, tab sis thaum lub sijhawm ua tiav, vim yog cov teeb meem kom qhuav thiab ntau dua lossis ntau ntxiv cov khoom tawg vim qhov chaw tsis zoo, qhov tsis zoo lossis cov khoom tsis zoo yog cov qhia. Nws tsis tuaj yeem raug tshem tawm thaum lub sijhawm ua daim ntawv cov txheej txheem.
(2) Kab rov tav thiab kab dej (kab txiv kab ntxwv kab). Cov dej ntws tawm los ntawm qhov tseeb tias cov khoom ntws los ntawm qhov tuag ntawm lub tshuab extruder nkag mus rau lub calender rolls vim tias tsis muaj cov khoom seem ntawm cov calender rolls, uas ua rau daim ntawv tsis sib dhos, thiab qhov saum npoo ntawm daim ntawv zoo li pluag li cov tev txiv kab ntxwv. Kab. Qhov kev daws teeb meem yog tias yuav tsum pom cov khoom seem ntawm cov calender rollers, thiab cov khoom seem rov qab pauv tusyees. Lub tshuab kab rov tav yog cov txheej txheem tsis xws luag ntawm cov txheej txheem extrusion, zoo ib yam li cov dej ntws ntawm txoj kev calendering, qhov kev nkag los ntawm kev sib txawv ntawm qhov nrawm ntawm ob txoj kab ntawm cov calender cov menyuam, txoj kev daws teeb meem yog kom muaj qhov peb-cov menyuam lub calender kev ceev ceev qhov tseeb tau hloov kho, thiab synchronization qhov tseeb yuav tsum tau txhim kho kom txo cov kab rov tav.
(3) Cov ntawv daj daj tuaj rau ntawm daim ntawv, cov xim dub lossis tsis huv, cov dej ntws, tsis sib dhos tsis sib luag, thiab lwm yam vim li cas qhov tshwm sim ntawm cov npuas hauv cov ntawv yog cov pellets tsis qhuav tag thiab cov ntsiab lus ya raws li 0.005%. Yog tias cov dej noo tsis txaus qhuav, nws yuav nkag mus tob rau hauv cov nplais kom qhia qhov tsim ntawm cov ntawv cog lus molecular lossis nyob twj ywm tob hauv cov hlais. Yog hais tias qhov ziab kom txias dhau lawm los yog lub sijhawm luv dhau, nws yuav cuam tshuam rau qhov ziab kom qhuav. Thaum cov hlwv tawg tshwm rau ntawm daim ntawv, lub ntsuas cua kom qhuav thiab lub sijhawm yuav tsum tau kho tam sim ntawd. Qhov laj thawj tseem ceeb ntawm cov ntawv daj los ntawm daim ntawv daj yog tias qhov ziab ziab kom kub dhau lossis lub sijhawm ntev dhau. Qhov kev ntsuas tseem ceeb nyob rau lub sijhawm no yog txhawm rau kom sov kom qhuav thiab txo lub sijhawm ziab. Lwm qhov laj thawj ntawm yellowing ntawm daim ntawv yog tias qhov kub ntawm cov yaj yog siab dhau. Nyob rau lub sijhawm no, cov hmoov av yuav tsum tau txo kom nrawm. Qhov laj thawj tseem ceeb rau cov pob dub thiab tsis huv hauv daim ntawv yog qhov lim lim tawg lossis qhov seem ntawm PET decomposition cov khoom hauv lub qhov txuas.
Cov ntsiab lus ntau lawm ntawm PET pob tshab ntawv
(1) Qhov pib mob tseem ceeb rau kev tsim cov PET pob tshab ntawv yog kev tswj hwm lub sijhawm kom qhuav thiab kub dej lwg kis. Lub ziab nyhuv ncaj qha txiav txim siab lub cev thiab khoom siv thiab ua tiav cov ntawv. Kev saib xyuas yuav tsum tau them rau kev tswj hwm qhov ntsuas kub thiab sijhawm thaum ziab. Qhov ziab ua kom sov thiab lub sijhawm tsis tuaj yeem siab dhau lossis tsis dhau. Yog tias lub lwg taw tes tsis tau qis, yuav tsum tau kuaj seb cov suab puas los ntawm lub ntsej muag. Lub suab laus laus laus tsis tuaj yeem nqus cov dej noo hauv huab cua thiab tsis tuaj yeem ua tiav lub hom phiaj kom ziab cov ziab. Lub sijhawm no, lub suab sib molecular yuav tsum tau hloov.
(2) Yog tias qhov kub ntawm cov yaj siab tshaj 280C, PET daim ntawv yuav raug muab tshem tawm los yog ploj mus, yog li cov kub ntawm cov yaj yuav tsum tswj hwm qis dua 280C.
(3) Lub ntsej muag tuag ntawm qhov tuag lub taub hau txiav txim siab lub tiaj thiab tuab uniformity ntawm daim ntawv. Qhov kub ntawm peb lub ntxuag ua lub luag haujlwm tseem ceeb hauv cov pob tshab thiab cov npoo ntawm daim ntawv ua tiav. Cov PET yaj xav tau sai sai zam qhov kub ntawm thaj chaw nrog qhov nrawm nrawm tshaj plaws. Los ntawm huab cua sov mus txog hauv qab kub crystallization, qhov kev ncua deb ntawm kev tuag thiab calender yob yog qhov tshwj xeeb.
