Xov xwm

Taw qhia rau Polyolefins thiab Film Extrusion

Polyolefins, ib chav kawm ntawm cov ntaub ntawv macromolecular synthesized los ntawm olefin monomers xws li ethylene thiab propylene, yog cov khoom siv dav tshaj plaws thiab siv cov yas thoob ntiaj teb. Lawv qhov kev nthuav dav tshwm sim los ntawm kev sib xyaw tshwj xeeb ntawm cov khoom, suav nrog tus nqi qis, kev ua haujlwm zoo, kev ruaj ntseg tshuaj lom neeg, thiab cov yam ntxwv ntawm lub cev. Ntawm cov kev siv ntau yam ntawm polyolefins, cov khoom ua yeeb yaj kiab tuav lub luag haujlwm tseem ceeb, ua haujlwm tseem ceeb hauv kev ntim khoom noj, npog ua liaj ua teb, ntim khoom lag luam, khoom siv kho mob thiab tu cev, thiab cov khoom siv niaj hnub. Feem ntau cov polyolefin resins ua haujlwm rau kev tsim cov yeeb yaj kiab suav nrog polyethylene (PE) - suav nrog Linear Low-Density Polyethylene (LLDPE), Low-density Polyethylene (LDPE), thiab High-Density Polyethylene (HDPE) - thiab polypropylene (PP).

Kev tsim cov yeeb yaj kiab polyolefin feem ntau yog nyob ntawm kev siv tshuab extrusion, nrog Blown Film Extrusion thiab Cast Film Extrusion yog ob txoj haujlwm tseem ceeb.

1. Tshuab tshuab Extrusion txheej txheem

Blown film extrusion yog ib txoj hauv kev tshaj plaws rau kev tsim cov yeeb yaj kiab polyolefin. Lub hauv paus ntsiab lus yog extruding ib tug molten polymer vertically upwards los ntawm ib tug annular tuag, tsim ib tug nyias-walled tubular parison. Tom qab ntawd, compressed cua yog nkag mus rau sab hauv ntawm lub parison no, ua rau nws mus rau hauv ib tug npuas nrog ib txoj kab uas hla loj dua qhov tuag. Raws li cov npuas ascends, nws yog forcibly txias thiab solidified los ntawm ib tug sab nraud cua nplhaib. Cov npuas dej txias yog tom qab ntawd tawg los ntawm ib txheej ntawm cov nip rollers (feem ntau ntawm ib qho kev sib tsoo lossis A-thav duab) thiab tom qab ntawd kos los ntawm traction rollers ua ntej raug mob rau hauv yob. Cov txheej txheem cua tshuab feem ntau ua rau cov yeeb yaj kiab nrog biaxial orientation, txhais tau tias lawv muaj qhov sib npaug zoo ntawm cov khoom siv tshuab hauv ob qho tib si lub tshuab kev taw qhia (MD) thiab kev hloov pauv (TD), xws li lub zog tensile, tsim kua muag, thiab kev cuam tshuam lub zog. Zaj duab xis tuab thiab cov khoom siv kho tshuab tuaj yeem tswj tau los ntawm kev hloov kho qhov sib piv (BUR - qhov piv ntawm npuas taub mus rau txoj kab uas hla) thiab qhov sib piv ntawm kos-down (DDR - piv ntawm kev thauj mus los ceev rau extrusion ceev).

2. Cast Film Extrusion txheej txheem

Cam khwb cia zaj duab xis extrusion yog lwm cov txheej txheem tseem ceeb heev rau polyolefin films, tshwj xeeb tshaj yog haum rau kev tsim cov yeeb yaj kiab uas xav tau cov khoom siv kho qhov muag zoo tshaj (xws li, siab clarity, siab gloss) thiab zoo heev thickness uniformity. Nyob rau hauv cov txheej txheem no, molten polymer yog extruded horizontally los ntawm ib tug ca, slot-type T-tuag, tsim ib tug uniform molten web. Lub vev xaib no yog rub tawm sai sai rau saum npoo ntawm ib lossis ntau qhov kev kub ceev, sab hauv txias txias yob. Lub yaj solidifies sai sai thaum kev sib cuag nrog lub txias yob nto. Cam khwb cia cov yeeb yaj kiab feem ntau muaj cov khoom siv kho qhov muag zoo, qhov muag muag, thiab zoo thaum tshav kub kub-sealability. Kev tswj xyuas meej ntawm qhov tuag di ncauj qhov sib txawv, txias dov kub, thiab kev sib hloov ceev tso cai rau kev tswj xyuas cov yeeb yaj kiab tuab thiab qhov zoo.

Sab saum toj 6 Polyolefin Film Extrusion Challenges

Txawm hais tias qhov kev loj hlob ntawm kev siv tshuab extrusion, cov tuam txhab lag luam feem ntau ntsib cov teeb meem kev ua haujlwm hauv kev tsim cov yeeb yaj kiab polyolefin, tshwj xeeb tshaj yog thaum siv zog ua haujlwm siab, ua haujlwm tau zoo, cov ntsuas nyias nyias, thiab thaum siv cov resins tshiab. Cov teeb meem no tsis tsuas yog cuam tshuam rau kev tsim khoom ruaj khov tab sis tseem cuam tshuam ncaj qha rau cov khoom kawg thiab tus nqi. Cov teeb meem tseem ceeb suav nrog:

1. Melt Fracture (Sharkskin): Qhov no yog ib qho tsis xws luag hauv polyolefin film extrusion. Macroscopically, nws manifests raws li ib ntus transverse ripples los yog ib tug irregularly ntxhib nto ntawm zaj duab xis, los yog nyob rau hauv loj heev, ntau pronounced distortions. Melt fracture feem ntau tshwm sim thaum tus nqi ntawm cov polymer yaj tawm ntawm qhov tuag ntau tshaj qhov tseem ceeb, ua rau cov nplaum-slip oscillations ntawm phab ntsa tuag thiab cov yaj ntau, lossis thaum qhov kev ntxhov siab txuas ntxiv ntawm qhov tuag tawm dhau lub zog yaj. Qhov kev tsis zoo no cuam tshuam rau cov yeeb yaj kiab kho qhov muag (clarity, gloss), nto smoothness, thiab tseem tuaj yeem ua rau nws cov khoom siv kho qhov muag thiab teeb meem.

2. Die Drool / Die Build-up: Qhov no yog hais txog kev sib sau ua ke ntawm cov khoom lag luam polymer degradation, tsis tshua muaj qhov hnyav molecular, cov khoom tsis zoo dispersed (xws li, pigments, antistatic agents, slip agents), los yog gels los ntawm cov resin ntawm cov di ncauj tuag los yog hauv cov kab noj hniav tuag. Cov kev tso nyiaj no tuaj yeem tshem tawm thaum lub sijhawm tsim khoom, ua rau lub ntsej muag tsis zoo thiab ua rau muaj qhov tsis xws luag xws li gels, streaks, lossis khawb, yog li cuam tshuam rau cov khoom muag thiab zoo. Nyob rau hauv cov xwm txheej hnyav, kev tuag tsim tuaj yeem thaiv qhov tuag tawm, ua rau kev ntsuas kev hloov pauv, kev ua yeeb yaj kiab tearing, thiab thaum kawg yuam cov kab ntau lawm kaw rau kev tu tuag, ua rau poob tseem ceeb hauv kev tsim khoom thiab cov khoom siv raw khoom pov tseg.

3. Kev kub siab extrusion thiab fluctuation: Nyob rau hauv tej yam kev mob, tshwj xeeb tshaj yog thaum ua cov high-viscosity resins los yog siv me me tuag gaps, lub siab nyob rau hauv lub extrusion system (tshwj xeeb tshaj yog nyob rau hauv lub extruder lub taub hau thiab tuag) yuav ua tau siab heev. Kev kub siab tsis yog tsuas yog ua rau lub zog siv zog xwb tab sis kuj ua rau muaj kev pheej hmoo rau cov cuab yeej siv tau ntev (xws li, ntsia hlau, chim, tuag) thiab kev nyab xeeb. Tsis tas li ntawd, qhov kev hloov pauv tsis ruaj khov hauv extrusion siab ncaj qha ua rau muaj kev hloov pauv hauv cov zis yaj, ua rau cov yeeb yaj kiab tsis sib xws.

4. Txwv tsis pub dhau: Txhawm rau tiv thaiv lossis txo cov teeb meem xws li tawg tawg thiab tuag tsim, cov tuam ntxhab feem ntau raug yuam kom txo qis extruder ntsia hlau ceev, yog li txwv cov kab ntau lawm. Qhov no cuam tshuam ncaj qha rau kev tsim khoom thiab cov nqi tsim khoom ntawm ib chav tsev ntawm cov khoom, ua rau nws nyuaj rau kev ua lag luam kev xav tau rau cov yeeb yaj kiab loj, tus nqi qis.

5. Nyuaj hauv Gauge Control: Instability nyob rau hauv melt flow, non-uniform kub faib nyob rau hauv lub tuag, thiab tuag build-up yuav ua rau tag nrho cov variations ntawm zaj duab xis thickness, transversely thiab longitudinally. Qhov no cuam tshuam rau cov yeeb yaj kiab tom qab ua tiav thiab cov yam ntxwv siv kawg.

6. Kev hloov pauv nyuaj: Thaum hloov pauv ntawm ntau hom lossis qib ntawm polyolefin resins, lossis thaum hloov xim masterbatches, cov khoom seem ntawm qhov kev khiav dhau los feem ntau nyuaj rau tshem tawm tag nrho ntawm extruder thiab tuag. Qhov no ua rau kev sib koom ua ke ntawm cov khoom qub thiab tshiab, tsim cov khoom hloov pauv, ncua sij hawm hloov pauv, thiab nce cov nqi seem.

Cov kev sib tw ua lag luam no txwv kev siv zog ntawm polyolefin film manufacturers los txhim kho cov khoom zoo thiab kev ua haujlwm zoo, thiab tseem ua rau muaj kev cuam tshuam rau kev siv cov ntaub ntawv tshiab thiab cov txheej txheem ua tiav. Yog li ntawd, nrhiav kev daws teeb meem zoo los daws cov teeb meem no yog qhov tseem ceeb rau kev txhim kho thiab kev noj qab haus huv ntawm tag nrho polyolefin zaj duab xis extrusion kev lag luam.

Kev daws rau Polyolefin Film Extrusion Txheej Txheem: Polymer Processing Aids (PPAs)

Polymer Processing Aids (PPAs) yog cov khoom siv ntxiv uas nws tus nqi tseem ceeb nyob rau hauv kev txhim kho tus cwj pwm rheological ntawm polymer melts thaum extrusion thiab hloov kho lawv cov kev cuam tshuam nrog cov khoom siv, yog li kov yeej ntau yam ntawm kev ua haujlwm nyuaj thiab txhim kho kev tsim khoom thiab cov khoom zoo.

1. Fluoropolymer-based PPAs

Chemical Structure and Characteristics: Cov no yog tam sim no siv dav tshaj plaws, thev naus laus zis paub tab, thiab pom tau zoo hauv chav kawm ntawm PPAs. Lawv feem ntau yog homopolymers lossis copolymers raws li fluoroolefin monomers xws li vinylidene fluoride (VDF), hexafluoropropylene (HFP), thiab tetrafluoroethylene (TFE), nrog fluoroelastomers yog tus sawv cev tshaj plaws. Cov saw hlau molecular ntawm cov PPAs yog nplua nuj nyob rau hauv high-bond-zog, low-polarity CF daim ntawv cog lus, uas qhia tshwj xeeb physicochemical zog: tsis tshua muaj zog nto (zoo li polytetrafluoroethylene / Teflon®), zoo heev thermal stability, thiab tshuaj inertness. Critically, fluoropolymer PPAs feem ntau pom tsis zoo sib xws nrog cov tsis-polar polyolefin matrices (xws li PE, PP). Qhov kev tsis sib haum xeeb no yog qhov tseem ceeb ua ntej rau lawv txoj kev tsiv teb tsaws chaw zoo rau cov hlau ntawm qhov tuag, qhov chaw uas lawv tsim cov txheej txheem lubricating dynamic.

Cov Khoom Muag Khoom Muag: Cov khoom lag luam ua lag luam thoob ntiaj teb rau fluoropolymer PPAs suav nrog Chemours 'Viton ™ FreeFlow™ series thiab 3M's Dynamar™ series, uas hais kom muaj kev lag luam tseem ceeb. Tsis tas li ntawd, qee qib fluoropolymer los ntawm Arkema (Kynar® series) thiab Solvay (Tecnoflon®) kuj tseem siv los ua, lossis yog cov khoom tseem ceeb hauv, PPA formulations.

2. Silicone-based Processing Aids (PPAs)

Chemical Structure and Characteristics: Cov khoom tseem ceeb hauv chav kawm ntawm PPAs no yog polysiloxanes, feem ntau hu ua silicones. Cov pob txha pob txha polysiloxane muaj alternating silicon thiab oxygen atoms (-Si-O-), nrog cov organic pawg (feem ntau methyl) txuas rau silicon atoms. Qhov tshwj xeeb no cov qauv molecular xaus cov ntaub ntawv Silicone nrog cov khoom ruaj khov, zoo heev, thiab tsis muaj adhesive cov khoom ntawm ntau yam tshuaj. Zoo ib yam li fluoropolymer PPAs, silicone-raws li PPAs ua haujlwm los ntawm kev tsiv mus rau cov hlau ntawm cov khoom siv los tsim cov txheej txheem lubricating.

Daim ntawv thov nta: Txawm hais tias fluoropolymer PPAs ua tus thawj coj ntawm polyolefin zaj duab xis extrusion sector, silicone-based PPAs tuaj yeem pom qhov zoo tshwj xeeb lossis tsim kev sib koom ua ke thaum siv hauv cov ntawv thov tshwj xeeb lossis koom nrog cov txheej txheem tshwj xeeb. Piv txwv li, lawv yuav raug txiav txim siab rau cov ntawv thov uas tsis tshua muaj coefficients ntawm kev sib txhuam los yog qhov twg cov yam ntxwv tshwj xeeb yog xav tau rau cov khoom kawg.

Ntsib Fluoropolymer Bans lossis PTFE Supply Challenges?

daws Polyolefin Film Extrusion Challenges nrog PFAS-dawb PPA Solutions-SILIKE's Fluorine Free Polymer additives

SILIKE siv txoj hauv kev zoo nrog nws cov khoom siv SILIMER series, muab cov tshiabPFAS-free polymer processing aids (PPAs). Cov khoom lag luam nthuav dav no nta 100% PFAS-dawb PPAs,fluorine-dawb PPA Polymer additives, thiabPFAS-dawb & fluorine-dawb PPA masterbatches.Los ntawmtshem tawm qhov xav tau ntawm fluorine additives, cov txheej txheem no pab txhawb kev tsim khoom rau LLDPE, LDPE, HDPE, mLLDPE, PP, thiab ntau yam txheej txheem polyolefin zaj duab xis extrusion. Lawv ua raws li cov cai tshiab ib puag ncig thaum tseem txhawb kev tsim khoom, txo qis qis qis, thiab txhim kho tag nrho cov khoom zoo. SILIKE's PFAS-dawb PPAs coj cov txiaj ntsig rau cov khoom kawg, suav nrog kev tshem tawm cov pob txha tawg (sharkskin), txhim kho smoothness, thiab zoo tshaj qhov saum npoo.

Yog tias koj tawm tsam nrog kev cuam tshuam ntawm fluoropolymer txwv lossis tsis txaus ntawm PTFE hauv koj cov txheej txheem polymer extrusion, SILIKE muajlwm txoj rau fluoropolymer PPAs / PTFE, PFAS-dawb additives rau film manufacturinguas yog tsim los ua kom tau raws li koj cov kev xav tau, tsis tas yuav hloov cov txheej txheem.