Cov Txheej Txheem Tsim Khoom PET Pob tshab thiab Cov Ntsiab Lus Tseem Ceeb

Muaj ntau hom ntawv yas thiab lawv siv dav. Tam sim no, cov hom tseem ceeb yog polyvinyl chloride, polystyrene thiab Polyester (PET)Ntawm lawv, cov ntawv PET muaj kev ua tau zoo, ua tau raws li cov kev cai ntawm lub teb chaws rau cov khoom molded thiab cov kev cai tiv thaiv ib puag ncig thoob ntiaj teb, thiab yog cov ntawv zoo rau ib puag ncig.

Cov ntaub ntawv raw ntawm cov ntawv PET

Ib yam li lwm cov yas, kev ua tau zoo ntawm cov ntawv PET muaj feem cuam tshuam nrog qhov hnyav molecular, thiab qhov viscosity intrinsic txiav txim siab qhov hnyav molecular. Qhov loj dua qhov viscosity intrinsic, qhov zoo dua qhov khoom siv lub cev thiab tshuaj lom neeg, tab sis qhov tsis zoo fluidity, uas ua rau molding nyuaj. Qhov qis dua qhov viscosity intrinsic, qhov tsis zoo qhov khoom siv lub cev thiab tshuaj lom neeg thiab qhov tsis zoo qhov cuam tshuam zog. Yog li ntawd, qhov viscosity intrinsic ntawm cov ntawv PET pob tshab yuav tsum tau xaiv los ntawm 0.8dl / g txog 0.9dl / g.

Cov txheej txheem tsim khoom PET

Cov khoom siv tseem ceeb rau cov ntawv pob tshab PET yog: lub pej thuam crystallization, lub pej thuam ziab, extruder, lub taub hau tuag, peb-yob calender, thiab winder.

Cov txheej txheem ntau lawm yog: cov khoom siv raw crystallization → ziab → extrusion plasticization → extrusion molding → calendering thiab shaping → winding khoom.

Kauj ruam thawj zaug yog crystallization

Cov daim PET raug cua sov thiab crystallized hauv lub pej thuam crystallization kom phim cov molecules, thiab tom qab ntawd qhov kub hloov pauv iav ntawm cov daim raug nce ntxiv kom tiv thaiv kev nplaum thaum lub sijhawm ziab thiab thaiv ntawm lub hopper.

Feem ntau, kev ua kom cov khoom siv crystallization yog ib kauj ruam tseem ceeb, uas siv sijhawm 30 feeb txog 90 feeb thiab qhov kub tsawg dua 149 ° C.

Kauj Ruam 2: Qhuav

Nyob rau hauv qhov kub siab, dej tuaj yeem ua rau PET hydrolyze thiab degrade, ua rau nws cov yam ntxwv adhesion txo qis. Nws cov khoom siv lub cev, tshwj xeeb tshaj yog lub zog cuam tshuam, yuav txo qis thaum qhov hnyav molecular txo qis. Yog li ntawd, PET yuav tsum tau ziab ua ntej yaj extrusion kom txo cov dej noo, thiab nws cov dej noo yuav tsum tsawg dua 0.005%.

Lub tshuab ziab kom qhuav dej siv rau kev ziab. Vim tias cov khoom PET yog hygroscopic, dej yuav nkag mus rau hauv qhov chaw ntawm daim los tsim cov molecular bonds, thiab lwm qhov ntawm cov dej yuav nyob tob hauv daim, ua rau kev ziab nyuaj. Yog li ntawd, cua kub ib txwm siv tsis tau.

Qhov chaw dej kub ntawm huab cua yuav tsum qis dua -40 ° C, thiab cua kub raug xa mus rau hauv lub qhov ziab khaub ncaws los ntawm lub voj voog kaw rau kev ziab tas mus li.

Kauj ruam thib peb yog extrusion molding

Tom qab crystallization thiab ziab, PET raug hloov mus ua ib qho polymer nrog lub melting point sib txawv. Lub molding kub ntawm cov polymer yog siab thiab qhov kev tswj kub yog nqaim.

Ib lub ntsia hlau thaiv uas mob siab rau polyester yog siv los cais cov pellets tsis yaj thiab cov yaj, uas yog qhov zoo rau kev tswj hwm cov txheej txheem shear ntev dua thiab ua kom cov zis ntawm extruder nce ntxiv.

Siv lub taub hau tuag uas yoog tau nrog tus pas nrig uas thaiv kev ntws. Lub taub hau tuag yog lub khob ntse, thiab txoj kev ntws thiab daim di ncauj tuag uas tsis khawb yuav tsum muaj qhov chaw tiav zoo. Lub cua sov ntawm lub taub hau tuag muaj lub luag haujlwm ntws thiab ntxuav. Qhov sib txawv ntawm daim di ncauj tuag ntawm lub taub hau tuag yuav tsum ua kom muaj kev sib npaug zoo. Qhov sib txawv ntawm daim di ncauj tuag ntawm lub taub hau tuag cuam tshuam ncaj qha rau qhov sib txawv ntawm cov tuab transverse thiab qhov tiaj tiaj ntawm daim ntawv.

Thaum extruding rau hauv daim ntawv, qhov kub sib xws ntawm thaj chaw pem hauv ntej ntawm lub cev, thaj chaw nruab nrab ntawm lub cev, thaj chaw tom qab ntawm lub cev, lub vijtsam hloov pauv, thiab lub pwm yog 240 ° C-260 ° C, 265 ° C-275 ° C, 260 ° C-265 ° C, 260 ° C-265 ° C, thiab 255 ° C-265 ° C, raws li.

Kauj Ruam 4: Txias thiab teeb tsa

Tom qab cov yaj tawm hauv lub pwm, nws ncaj qha mus rau hauv peb-yob calender rau calendering thiab txias. Qhov deb ntawm peb-yob calender thiab lub pwm feem ntau khaws cia ntawm kwv yees li 8 cm. Yog tias qhov deb loj dhau, daim ntawv yooj yim rau sag thiab wrinkle, ua rau daim ntawv tiav tsis zoo. Tsis tas li ntawd, vim qhov deb loj, qhov cua sov dissipation thiab txias qeeb dhau, ua rau crystallization thiab whitening, uas tsis zoo rau calendering.

Lub tshuab calender peb-yob muaj peb lub rollers: sab saud, nruab nrab thiab qis dua. Lub axis ntawm nruab nrab roller yog kho. Thaum lub sijhawm txias thiab calendering, qhov kub ntawm qhov chaw ntawm lub roller yog 40 ° C-50 ° C, thiab lub axis ntawm cov rollers sab saud thiab qis tuaj yeem txav mus rau saum thiab nqis. Qhov sib txawv ntawm lub roller raug kho los ntawm kev txav lub axis mus rau saum thiab nqis. Qhov kub ntawm cov rollers sab saud thiab qis yog 30 ° C-60 ° C thiab 52 ° C-68 ° C feem. Peb lub rollers yuav tsum ua kom muaj kev sib dhos ceev, thiab qhov ceev yuav tsum siab dua qhov ceev extrusion. Lub hom phiaj yog los them rau qhov nthuav dav ntawm cov khoom thaum nws tawm hauv lub pwm thiab txo qhov kev ntxhov siab sab hauv ntawm daim ntawv, yog li ntawd cov wrinkles ploj mus.

Tus tsiaj yuav crystallize nyob rau hauv qhov ntau ntawm 100 ° C-250 ° C, thiab qhov ceev tshaj plaws crystallization yog 140 ° C-180 ° C, yog li crystallization tuaj yeem ua tiav hauv ob peb feeb xwb. Tus tsiaj yuav tsum dhau los ntawm thaj chaw kub crystallization no sai sai thiab qhov kub ntawm peb lub rollers yuav tsum tau tswj hwm nruj me ntsis.

Kauj ruam thib tsib yog rub thiab winding

Daim ntawv hla dhau lub calender roller thiab nkag mus rau hauv lub cuab yeej traction los ntawm lub roller qhia. Lub cuab yeej traction muaj lub roller roj hmab nquag thiab lub roller roj hmab passive. Lub siab cua nias ob lub rollers nruj nreem kom tiv thaiv daim ntawv los ntawm kev raug flattened los ntawm lub calender roller thaum daim ntawv hla dhau ob lub rollers thiab raug rub mus rau lub cuab yeej winding.

Cov txheej txheem tsim cov ntawv PET

(1) Cov xwm txheej tseem ceeb rau kev tsim cov ntawv pob tshab PET yog lub sijhawm ziab thiab kev tswj hwm ntawm qhov chaw dej kub ntawm huab cua. Qhov cuam tshuam ntawm kev ziab ncaj qha txiav txim siab qhov khoom siv lub cev thiab cov khoom siv kho tshuab thiab kev tsim khoom ntawm daim ntawv.
Thaum lub sijhawm ziab, yuav tsum tau saib xyuas qhov kub thiab lub sijhawm ziab. Qhov kub thiab lub sijhawm ziab yuav tsum tsis txhob siab dhau lossis qis dhau. Yog tias qhov dew point tsis tuaj yeem txo tau, yuav tsum tau kuaj xyuas qhov xwm txheej ntawm lub molecular sieve. Lub molecular sieve uas laus lawm tsis tuaj yeem nqus tau cov dej noo hauv huab cua, thiab lub hom phiaj ntawm kev ziab thiab txiav tsis tuaj yeem ua tiav. Lub sijhawm no, lub molecular sieve yuav tsum tau hloov.

(2) Yog tias qhov kub ntawm cov yaj tshaj 280 ° C, qhov PET daim ntawv yuav hloov xim lossis lwj. Yog li ntawd, qhov kub yaj yuav tsum tswj tau qis dua 280 ° C.

(3) Qhov sib txawv ntawm daim di ncauj tuag ntawm lub taub hau tuag txiav txim siab qhov tiaj tiaj thiab tuab sib xws ntawm daim ntawv. Qhov kub ntawm peb lub rollers ua lub luag haujlwm tseem ceeb hauv qhov pob tshab thiab qhov tiav ntawm daim ntawv. PET yaj yuav tsum zam kom sai sai ntawm thaj chaw kub crystallization ceev tshaj plaws thiab tam sim ntawd poob ntawm qhov kub yaj mus rau qis dua qhov kub crystallization. Yog li ntawd, qhov deb ntawm lub taub hau tuag thiab lub calender roller yog qhov tseem ceeb heev.