Cov Txheej Txheem Extrusion rau Polypropylene Yas thiab Nws Cov Ntawv Siv hauv Kev Ntim Khoom
Polypropylene (PP) yog ib qho ntawm cov thermoplastics siv dav tshaj plaws thoob ntiaj teb, tshwj xeeb tshaj yog rau kev ntim khoom. PP qhov nrov npe yog los ntawm nws qhov kev sib xyaw ua ke ntawm lub teeb yuag, tshuaj lom neeg tsis kam, lub zog sib piv, thiab kev tiv taus cua sov piv rau ntau lwm yam khoom yas. Ntawm nws ntau txoj kev ua tiav, extrusion yog qhov tseem ceeb tshwj xeeb, vim nws tuaj yeem tsim cov khoom txuas ntxiv xws li zaj duab xis, ntawv, daim kab xev, thiab ntau yam profiles siv dav hauv kev lag luam ntim khoom. Tsab xov xwm no tham txog cov ntsiab cai ntawm extrusion txheej txheem rau PP, nws cov theem ua tiav, cov yam ntxwv tseem ceeb, cov teeb meem, thiab nws cov ntawv thov hauv kev ntim khoom.
1. Kev Txheeb Xyuas Txog Polypropylene Rau Kev Ntim Khoom
PP yog ib qho polymer ntawm propylene monomer nrog cov qauv semi-crystalline. Qhov xwm txheej semi-crystalline no muab kev sib npaug ntawm lub zog kho tshuab thiab kev ywj pheej, nrog rau kev tiv taus zoo rau cov kuab tshuaj thiab tshuaj lom neeg. Hauv kev ntim khoom, PP feem ntau raug xaiv vim tias:
1. Tiv taus roj thiab tshuaj lom neeg (haum rau cov khoom noj uas muaj roj).
2. Kub ruaj khov (qee qib tsim nyog rau kev sau kub lossis cua sov nruab nrab).
3. Yooj yim rau kev tsim ua cov zaj duab xis nyias, cov ntawv tawv, lossis cov fibers.
4. Qhov ceev tsawg yog li cov khoom sib dua.
5. Muaj peev xwm siv dua tshiab (resin code 5), txawm hais tias lub kaw lus rov ua dua tshiab txawv hauv txhua cheeb tsam.
Txawm li cas los xij, PP kuj muaj cov teeb meem xws li kev tiv thaiv UV tsawg yam tsis muaj cov khoom ntxiv, nrog rau cov khoom thaiv pa oxygen uas tsis zoo li lwm cov ntaub ntawv, yog li ntawd hauv qee daim ntawv thov yuav tsum muaj cov qauv ntau txheej lossis txheej txheej.
2. Cov Ntsiab Cai Tseem Ceeb ntawm Kev Rho Tawm hauv PP
Kev rho tawm yog txheej txheem ntawm kev xa cov khoom polymer yaj tas li los ntawm lub pwm kom tsim tau ib daim duab tshwj xeeb. Rau PP, cov pellets lossis granules raug pub rau hauv lub hopper thiab tom qab ntawd thawb los ntawm lub hau ntswj rau hauv lub thoob kub. Thaum lawv mus rau lub pwm, cov khoom raug cua sov, sib xyaw, thiab yaj kom txog thaum nws dhau los ua cov yaj sib xws.
Lub tswv yim tseem ceeb ntawm extrusion yog kev tswj hwm:
- Kub (yog li ntawd PP yaj ruaj khov yam tsis muaj kev puas tsuaj),
- Siab thiab ntws nrawm (kom paub tseeb tias cov khoom loj sib xws),
- Txias (kom "xauv" cov duab, cov qauv siv lead ua, thiab cov khoom siv kho tshuab).
Hauv kev lag luam ntim khoom, extrusion rau PP feem ntau yog ua ke nrog cov txheej txheem ntxiv xws li kev taw qhia (BOPP / CPP), lamination, lossis thermoforming.
3. Cov Khoom Siv Tseem Ceeb hauv Cov Txheej Txheem Extrusion
Cov txheej txheem PP extrusion feem ntau muaj:
1. Lub Hopper thiab kev pub mis
Tswj kev muab cov khoom PP pellets, qee zaum nruab nrog lub tshuab ziab khaub ncaws (txawm hais tias PP tsis rhiab heev rau cov dej noo li PET, kev tswj kev ua qias tuaj tseem ceeb heev).
2. Extruder (ib lub hau los yog ob lub hau)
- Ib lub tshuab extruder ib leeg yog feem ntau rau zaj duab xis / daim ntawv.
- Cov extruders twin-screw feem ntau siv rau kev sib xyaw (sib tov cov khoom ntxiv, cov khoom sau, cov masterbatches) vim lawv muaj peev xwm sib xyaw zoo dua.
3. Cov cua sov hauv lub thoob thiab kev tswj qhov kub thiab txias hauv cheeb tsam
Lub tshuab extruder muab faib ua ntau thaj chaw cua sov. Kev tswj qhov kub kom raug tswj tau qhov ruaj khov ntawm cov yaj viscosity.
4. Lub tshuab hloov pauv thiab lub phaj tawg
Lim cov pa phem, txhim kho qhov sib xws ntawm cov yaj, thiab tswj qhov siab.
5. Tuag (faj tuag, annular tuag, profile tuag)
Lub pwm txiav txim siab qhov pib ntawm cov khoom: daim ntawv tiaj tus / zaj duab xis, zaj duab xis tshuab, lossis cov ntaub ntawv profile.
6. Lub kaw lus txias thiab tshem tawm
Nws tuaj yeem yog lub dov txias rau zaj duab xis/daim ntawv, lub nplhaib cua rau zaj duab xis uas cua tshuab, thiab lub dov nip kom rub cov khoom tawm.
7. Lub tshuab cua los yog lub tshuab txiav
Cov khoom siv zaj duab xis feem ntau yog dov; daim ntawv feem ntau raug txiav lossis raug thermoforming.
4. Cov Theem ntawm Cov Txheej Txheem PP Extrusion
Feem ntau, cov theem PP extrusion yog:
1. Kev Pub Noj: PP pellets nkag mus rau hauv lub thoob.
2. Kev ua yas thiab yaj: lub hau ntswj cua sov los ntawm kev sib xyaw ua ke ntawm kev cua sov sab nraud thiab kev sib txhuam.
3. Kev sib tov: cov khoom ntxiv (cov tshuaj antioxidants, cov neeg ua haujlwm plam, cov tshuaj tiv thaiv kev thaiv, cov khoom sau, cov xim) raug faib sib npaug.
4. Kev lim dej yaj: lub vijtsam lim cov khoom txawv teb chaws.
5. Tsim los ntawm lub pwm: cov yaj tawm los raws li cov duab ntawm lub pwm.
6. Kev txias: txiav txim siab qhov zoo ntawm qhov chaw, tuab, thiab kev taw qhia ntawm cov molecule.
7. Kev Ua Tiav: kev txiav, kev sib txuas, lossis lwm yam txheej txheem xws li lamination thiab luam ntawv.
5. Cov Txheej Txheem Tseem Ceeb thiab Lawv Qhov Cuam Tshuam rau Qhov Zoo
Qee cov ntsiab lus tseem ceeb hauv PP extrusion:
- Cov qauv kub ntawm lub thoob thiab tuag
Qhov kub qis dhau ua rau cov khoom yaj tsis sib xws thiab ua rau saum npoo ntxhib; qhov kub siab dhau ua rau muaj kev puas tsuaj (ntxhiab tsw, tsis muaj xim, txo cov khoom siv kho tshuab). PP feem ntau yog ua tiav ntawm qhov kub thiab txias ntawm cov khoom yaj thiab pwm, feem ntau nyob ib puag ncig 180–240 ° C hauv ntau daim ntawv thov, tab sis ib txwm nyob ntawm MFI (Melt Flow Index) thiab kev tsim tshuab.
- Qhov ceev ntawm cov ntsia hlau thiab lub zog rov qab
Cuam tshuam rau kev txiav thiab kev sib tov. Qhov kub siab dhau tuaj yeem ua rau qhov kub yaj ntau dhau thiab ua rau gelling lossis degradation.
- Kev tswj qhov tuab thiab qhov ntsuas
Hauv cov yeeb yaj kiab thiab cov ntawv, qhov sib txawv ntawm qhov tuab cuam tshuam rau lub zog, kev zoo nkauj, thiab kev ua haujlwm ntawm kev kaw. Cov txheej txheem tswj qhov tuab (piv txwv li, cov ntsia hlau uas tsis siv neeg lossis cov nplhaib cua uas hloov kho tau) feem ntau siv.
- Txias thiab crystallization
PP yog semi-crystalline; qhov txias txias cuam tshuam rau qib ntawm crystallinity, clarity, thiab stiffness. Kev txias sai sai feem ntau txhim kho qhov meej hauv qee qhov kev siv, tab sis kuj tuaj yeem cuam tshuam rau shrinkage thiab warpage.
- Cov Khoom Ntxiv
Rau kev ntim khoom, cov khoom ntxiv uas siv ntau suav nrog cov tshuaj antioxidants (kev ruaj khov ntawm qhov kub), cov neeg sawv cev slip (txo qhov coefficient ntawm kev sib txhuam), cov neeg sawv cev antiblocking (tiv thaiv cov yeeb yaj kiab kom tsis txhob lo ua ke), cov neeg sawv cev nucleating (tswj cov crystallization), thiab cov neeg sawv cev antistatic.
6. Hom PP Extrusion rau Cov Khoom Ntim Khoom
a) Cast Film Extrusion (CPP - Cast Polypropylene)
Hauv zaj duab xis cam khwb cia, cov yaj tawm ntawm lub pwm tiaj tus thiab tom qab ntawd txias sai sai rau ntawm lub yob txias, tsim cov zaj duab xis nrog cov tuab sib npaug thiab zoo nkauj. CPP feem ntau siv rau:
- ntim khoom noj txom ncauj,
- laminate nrog lwm cov ntaub ntawv,
- cov hnab thiab cov ntawv qhwv ntws,
- txheej sealing (txheej kaw cua sov) ntawm cov qauv ntau txheej.
Cov txiaj ntsig ntawm CPP: qhov meej zoo, yooj yim rau kev kaw, thiab cov txheej txheem ruaj khov rau kev tsim khoom ntau.
b) Tshuab Zaj Duab Xis Extrusion
Cov yeeb yaj kiab cua kuj siv rau PP, txawm hais tias nws feem ntau siv nrog PE. Cov yeeb yaj kiab no yog tsim los ntawm lub pwm annular, cua rau hauv lub npuas, thiab tom qab ntawd txias los ntawm lub nplhaib cua. Nws cov txiaj ntsig suav nrog kev ywj pheej hauv kev taw qhia thiab tuab, thiab lub peev xwm los tsim cov yeeb yaj kiab tubular. Cov ntawv thov suav nrog ntau hom hnab thiab cov ntaub, txawm hais tias qhov kev thov loj tshaj plaws rau cov yeeb yaj kiab cua tseem yog rau PE.
c) Daim Ntawv Extrusion rau Thermoforming
Daim ntawv PP yog extruded rau hauv cov ntawv, ces nws tuaj yeem raug cua sov thiab tsim los ntawm thermoforming rau hauv:
- ib khob mis nyuj yogurt,
- cov tais zaub mov uas npaj txhij noj tau,
- cov thawv microwave (rau qee qib),
- lub hau thiab qhov ntxig.
PP nrov rau cov tais vim nws tiv taus cua sov zoo dua li PS, thiab tiv taus tshuaj lom neeg zoo.
d) Daim kab xev/Strapping Extrusion
PP raug nias rau hauv daim kab xev thiab tom qab ntawd rub kom muaj zog ntxiv, ua ib txoj hlua khi rau khi cov thawv ntawv thiab cov pallets. Qhov no suav nrog kev ntim khoom thib ob/theem peb, tseem ceeb hauv kev xa khoom.
e) Kev Txheej Txheem Extrusion thiab Lamination
PP siv tau ua ib txheej rau ntawm cov khoom siv xws li ntawv lossis lwm yam yeeb yaj kiab los txhim kho kev tiv thaiv dej/roj thiab kev ua haujlwm kaw. Hauv kev lag luam ntim khoom yooj ywm, PP feem ntau yog ib feem ntawm cov qauv laminate, piv txwv li, los sib npaug tus nqi, lub zog, thiab kev ua haujlwm kaw.
7. Kev Sib Tw ntawm Kev Tsim Khoom thiab Kev Tswj Xyuas Zoo
Qee qhov teeb meem uas feem ntau tshwm sim nrog PP extrusion suav nrog:
- Gel thiab fisheye vim muaj kuab paug lossis yaj tsis sib xws.
- Cov kab tuag (cov kab ntawm qhov chaw) vim yog cov av tuag lossis cov dej ntws tsis sib npaug.
- Qhov tuab tsis sib xws vim yog kev tswj hwm tsis zoo ntawm kev tuag / txias.
- Kev tawg ntawm daim ntawv vim yog qhov txias tsis sib xws lossis kev ntxhov siab seem.
- Nyuaj rau kev luam ntawv thiab lamination vim yog lub zog ntawm PP uas tsis tshua muaj zog; feem ntau xav tau kev kho mob corona lossis plasma kom txhim kho kev nplaum ntawm cov kua mem / nplaum.
Kev tswj xyuas zoo feem ntau suav nrog kev ntsuas qhov tuab, qhov tsaus ntuj thiab qhov meej, lub zog tensile, coefficient ntawm kev sib txhuam (COF), kev sim lub zog foob, thiab kev tshuaj xyuas pom rau qhov tsis zoo ntawm qhov chaw.
8. Cov Qauv thiab Kev Tsim Kho Tshiab: Sib dua thiab ruaj khov dua
Nyob rau xyoo tas los no, kev lag luam ntim khoom tau thawb kom txo cov khoom siv (downgauging) thiab nce kev siv rov qab. Hauv PP, cov tswv yim tshiab suav nrog:
- siv cov neeg sawv cev nucleating los ua kom tawv kom cov zaj duab xis tuaj yeem ua kom nyias dua,
– Tsim cov khoom siv ib leeg ua los ntawm PP kom yooj yim dua rau kev siv dua (piv rau cov qauv sib xyaw ua ke),
- siv cov PP rov ua dua tshiab (rPP) rau cov ntawv thov tsis tseem ceeb lossis nrog qee qhov kev xav tau,
- kev tsim cov qib PP nrog kev pom tseeb zoo dua los hloov lwm cov ntaub ntawv hauv cov pob tshab.
Xaus
Kev siv tshuab extrusion yog lub hauv paus tseem ceeb ntawm kev ua polypropylene rau kev lag luam ntim khoom, uas muaj peev xwm tsim cov khoom lag luam txuas ntxiv xws li zaj duab xis, daim ntawv, thiab daim kab xev nrog kev tsim khoom siab. Kev ua tiav ntawm cov txheej txheem yog cuam tshuam los ntawm kev tswj qhov kub thiab txias, qhov ceev ntawm lub hau ntswj, kev tsim pwm, kev txias, thiab kev xaiv cov khoom ntxiv tsim nyog. Nws cov ntawv thov yog dav, xws li CPP rau kev ntim khoom yooj ywm, PP daim ntawv rau cov thawv ntim khoom noj thermoforming, mus rau strapping rau kev ntim khoom logistics. Nyob rau hauv qhov kev thov kom ruaj khov, PP extrusion kuj tseem txav mus rau qhov sib dua, cov qauv ntim khoom rov ua dua tshiab uas tseem ua tau raws li cov khoom ua tau zoo thiab kev nyab xeeb.
Yog tias koj xav tau, kuv tuaj yeem pab tsim ib qho version uas muaj kev txawj ntse ntau dua (nrog rau cov duab qhia txog cov txheej txheem, cov qauv ntsuas ib txwm muaj rau txhua daim ntawv thov, lossis cov ntaub ntawv kawm txog kev ntim khoom noj) lossis ib qho version nrov dua rau cov neeg nyeem dav dav.
