Nkhani

Chiyambi cha Polyolefins ndi Mafilimu Extrusion

Ma Polyolefin, gulu lazinthu zazikuluzikulu zopangidwa kuchokera ku olefin monomers monga ethylene ndi propylene, ndi mapulasitiki opangidwa ndikugwiritsidwa ntchito kwambiri padziko lonse lapansi. Kuchuluka kwawo kumabwera chifukwa chophatikizana kwapadera kwa zinthu, kuphatikiza mtengo wotsika, kutheka kwabwino kwambiri, kukhazikika kwamphamvu kwamankhwala, komanso mawonekedwe athupi. Mwa mitundu yosiyanasiyana ya ma polyolefin, zinthu zamakanema zimakhala ndi malo ofunikira kwambiri, zimagwira ntchito zofunika pakupakira zakudya, zophimba zaulimi, zoyika m'mafakitale, zamankhwala ndi zaukhondo, komanso zinthu zogula tsiku ndi tsiku. Mitundu yambiri ya polyolefin resins yomwe imagwiritsidwa ntchito popanga mafilimu ndi polyethylene (PE) - kuphatikiza Linear Low-Density Polyethylene (LLDPE), Low-Density Polyethylene (LDPE), ndi High-Density Polyethylene (HDPE) - ndi polypropylene (PP).

Kupanga mafilimu a polyolefin makamaka kumadalira luso la extrusion, ndi Blown Film Extrusion ndi Cast Film Extrusion kukhala njira ziwiri zazikuluzikulu.

1. Wowombedwa Film Extrusion Njira

Kuphulika kwa filimu extrusion ndi imodzi mwa njira zofala kwambiri zopangira mafilimu a polyolefin. Mfundo yofunikira imaphatikizapo kutulutsa polima wosungunuka molunjika m'mwamba kudzera mukufa kwapachaka, kupanga parison yokhala ndi mipanda yopyapyala. Pambuyo pake, mpweya woponderezedwa umalowetsedwa mkati mwa parishiyi, ndikupangitsa kuti ilowe mu thovu lokhala ndi mainchesi akulu kwambiri kuposa kufa. Pamene kuwirako kukwera, kumawunikiridwa mwamphamvu ndikukhazikika ndi mphete yakunja ya mpweya. Kuwira koziziritsako kumaphwanyidwa ndi ma nip rollers (nthawi zambiri kudzera pa chimango chogwa kapena A-frame) ndipo kenako amakokedwa ndi zodzigudubuza asanavulazidwe pa mpukutu. Kanema wowomberedwa nthawi zambiri amatulutsa makanema okhala ndi biaxial orientation, kutanthauza kuti amawonetsa magwiridwe antchito pamakina onse (MD) ndi njira yodutsamo (TD), monga kulimba kwamphamvu, kukana misozi, komanso mphamvu yamphamvu. Makulidwe a filimu ndi mawotchi amatha kuwongoleredwa posintha chiŵerengero cha kuwombera (BUR - chiŵerengero cha kuwira m'mimba mwake mpaka kufa m'mimba mwake) ndi chiŵerengero chojambula pansi (DDR - chiŵerengero cha kuthamanga kwa kuthamanga kwa extrusion).

2. Osewera Mafilimu Extrusion Njira

Cast film extrusion ndi njira ina yofunika kwambiri yopangira mafilimu a polyolefin, oyenerera makamaka kupanga makanema omwe amafunikira mawonekedwe apamwamba kwambiri (mwachitsanzo, kumveka bwino, gloss kwambiri) komanso makulidwe abwino kwambiri. Pochita izi, polima wosungunuka amatulutsidwa mopingasa kudzera pamtundu wa T-die wathyathyathya, ndikupanga ukonde wosungunuka wofanana. Ukondewu umakokedwa mwachangu pamwamba pa gudumu limodzi kapena zingapo zothamanga kwambiri, zoziziritsidwa mkati. Chisungunukocho chimalimba msanga pokhudzana ndi malo ozizira. Makanema a Cast nthawi zambiri amakhala ndi mawonekedwe owoneka bwino, omveka bwino, komanso amatha kutentha kwambiri. Kuwongolera kolondola pa kusiyana kwa milomo yakufa, kutentha kwa chill roll, ndi liwiro lozungulira zimalola kuwongolera kolondola kwa makulidwe a filimu ndi mawonekedwe apamwamba.

Zovuta 6 Zapamwamba Zowonjezera Mafilimu a Polyolefin

Ngakhale kukhwima kwa ukadaulo wa extrusion, opanga nthawi zambiri amakumana ndi zovuta zingapo pakukonza mafilimu a polyolefin, makamaka akamafunitsitsa kutulutsa kwambiri, kuchita bwino, zoyezera zocheperako, komanso kugwiritsa ntchito utomoni watsopano wochita bwino kwambiri. Izi sizimangokhudza kukhazikika kwa kupanga komanso zimakhudzanso mtengo wazinthu zomaliza komanso mtengo wake. Mavuto akulu ndi awa:

1. Sungunulani Fracture (Sharkskin): Ichi ndi chimodzi mwa zolakwika zambiri mu polyolefin filimu extrusion. Pamawonekedwe a macroscopically, amawonekera ngati mafunde opindika nthawi ndi nthawi kapena malo owoneka bwino pafilimuyo, kapena pazovuta kwambiri, kupotoza kowonekera kwambiri. Sungunulani fracture imachitika pamene kumeta ubweya wa polima kusungunula kuchoka ku imfa kumaposa mtengo wovuta, zomwe zimapangitsa kuti pakhale kugwedezeka kwachitsulo pakati pa khoma lakufa ndi kusungunuka kwakukulu, kapena pamene kupanikizika kowonjezera pa kutuluka kwakufa kumaposa mphamvu yosungunuka. Kuwonongeka kumeneku kumasokoneza kwambiri mawonekedwe a filimuyi (kumveka bwino, gloss), kusalala kwa pamwamba, komanso kusokoneza makina ake ndi zotchinga.

2. Die Drool / Die Build-up: Izi zikutanthauza kudzikundikira pang'onopang'ono kwa zinthu zowononga polima, tizigawo tating'ono tating'onoting'ono ta mamolekyulu, zowonjezera zosabalalika bwino (mwachitsanzo, ma pigment, antistatic agents, slip agents), kapena ma gels ochokera ku utomoni m'mphepete mwa milomo yakufa kapena m'mphepete. Ma depositiwa amatha kutsekeka panthawi yopanga, kuwononga filimuyo ndikuyambitsa zolakwika monga ma gels, mikwingwirima, kapena zokwawa, potero zimakhudza mawonekedwe ndi mtundu wazinthu. Zikavuta kwambiri, kukwera kwa kufa kumatha kuletsa kutuluka kwakufa, zomwe zimapangitsa kuti ma geji asinthe, kung'ambika kwa filimu, ndipo pamapeto pake kukakamiza kuyimitsidwa kwa mzere wopanga kuti ayeretse kufa, zomwe zimapangitsa kuti pakhale kuwonongeka kwakukulu pakupanga bwino komanso kuwonongeka kwa zinthu.

3. High Extrusion Pressure and Fluctuation: Pazifukwa zina, makamaka pokonza utomoni wapamwamba kwambiri kapena kugwiritsa ntchito mipata yaying'ono yakufa, kupanikizika mkati mwa dongosolo la extrusion (makamaka pamutu wa extruder ndi kufa) kumatha kukhala kwakukulu kwambiri. Kuthamanga kwambiri sikumangowonjezera kugwiritsa ntchito mphamvu komanso kumadzetsa chiwopsezo ku moyo wautali wa zida (monga, zomangira, mbiya, kufa) ndi chitetezo. Kuphatikiza apo, kusinthasintha kosasunthika kwa kuthamanga kwa extrusion kumayambitsa kusiyanasiyana kwazomwe zimasungunuka, zomwe zimapangitsa kuti filimuyo ikhale yosafanana.

4. Zomwe Zimagwira Ntchito Pang'ono: Pofuna kupewa kapena kuchepetsa nkhani monga kusungunuka kwa ng'anjo ndi kufa, opanga nthawi zambiri amakakamizika kuchepetsa liwiro la wononga wononga, potero kuchepetsa kutulutsa kwa mzere wopangira. Izi zimakhudza mwachindunji kupanga komanso mtengo wopangira pagawo lililonse lazinthu, zomwe zimapangitsa kuti zikhale zovuta kukwaniritsa zofuna zamisika zamakanema akuluakulu, otsika mtengo.

5. Kuvuta kwa Kuwongolera kwa Gauge: Kusasunthika kwa kusungunuka kwa kusungunuka, kugawanika kwa kutentha kosafanana pakati pa kufa, ndi kufa kumangiriza kungapangitse kusiyana kwa makulidwe a filimu, mozungulira ndi motalika. Izi zimakhudza momwe filimuyo imagwiritsidwira ntchito komanso mawonekedwe omaliza.

6. Kusintha kwa utomoni Wovuta: Mukamasintha pakati pa mitundu yosiyanasiyana kapena magiredi a resin a polyolefin, kapena posintha ma masterbatches amtundu, zinthu zotsalira kuchokera kumayendedwe am'mbuyomu nthawi zambiri zimakhala zovuta kuyeretsa kwathunthu kuchokera ku extruder ndi kufa. Izi zimabweretsa kusanganikirana kwa zida zakale ndi zatsopano, kupanga zinthu zosinthira, kukulitsa nthawi yosinthira, komanso kuchuluka kwa zinthu zomwe zidawonongeka.

Mavuto odziwika bwinowa amalepheretsa kuyesetsa kwa opanga mafilimu a polyolefin kuti apititse patsogolo luso lazinthu komanso kupanga bwino, komanso kuletsa kutengera zida zatsopano ndi njira zapamwamba zopangira. Choncho, kufunafuna njira zothetsera mavutowa n'kofunika kwambiri kuti chitukuko chokhazikika komanso chathanzi cha makampani onse a polyolefin extrusion.

Mayankho a Polyolefin Film Extrusion Process: Polymer Processing Aids (PPAs)

Polymer Processing Aids (PPAs) ndi zowonjezera zomwe phindu lake lalikulu limakhala pakuwongolera machitidwe a polima amasungunuka panthawi yotulutsa ndikusintha momwe amalumikizirana ndi zida, potero amathetsa zovuta zingapo pokonza ndikukulitsa luso la kupanga ndi mtundu wazinthu.

1. Ma PPA opangidwa ndi fluoropolymer

Kapangidwe ka Mankhwala ndi Makhalidwe: Awa ndi magulu omwe amagwiritsidwa ntchito kwambiri, okhwima mwaukadaulo, komanso owoneka bwino a PPA. Nthawi zambiri amakhala ma homopolymers kapena copolymers kutengera fluoroolefin monomers monga vinylidene fluoride (VDF), hexafluoropropylene (HFP), ndi tetrafluoroethylene (TFE), ndi fluoroelastomers kukhala oimira kwambiri. Unyolo wa maselo a PPAs ndi wolemera mu ma bond-energy, low-polarity CF bonds, omwe amapereka mawonekedwe apadera a physicochemical: mphamvu zotsika kwambiri zapamtunda (monga polytetrafluoroethylene/Teflon®), kukhazikika kwabwino kwa kutentha, ndi kusakhazikika kwamankhwala. Mwachidule, ma PPA a fluoropolymer nthawi zambiri amawonetsa kusagwirizana ndi matrices a polyolefin omwe si a polar (monga PE, PP). Kusagwirizana kumeneku ndikofunikira kwambiri pakusamuka kwawo kogwira mtima kupita kuzitsulo zakufa, komwe amapanga zokutira zolimbitsa thupi.

Zogulitsa Zoyimilira: Zotsogola pamsika wapadziko lonse wa fluoropolymer PPAs zikuphatikiza mndandanda wa Chemours 'Viton™ FreeFlow™ ndi mndandanda wa 3M's Dynamar™, womwe umatsogolera gawo lalikulu pamsika. Kuphatikiza apo, magiredi ena a fluoropolymer ochokera ku Arkema (mndandanda wa Kynar®) ndi Solvay (Tecnoflon®) amagwiritsidwanso ntchito ngati, kapena ndi zigawo zikuluzikulu, ma PPA.

2. Silicone-based Processing Aids (PPAs)

Kapangidwe ka Mankhwala ndi Makhalidwe: Zomwe zimagwira ntchito m'gulu ili la PPAs ndi ma polysiloxanes, omwe amadziwika kuti silicones. Msana wa polysiloxane uli ndi silicon ndi ma atomu okosijeni (-Si-O-), okhala ndi magulu achilengedwe (makamaka methyl) omwe amamangiriridwa ku maatomu a silicon. Mapangidwe apadera a mamolekyuwa amapatsa zida za silikoni zomwe zimakhala zotsika kwambiri, kukhazikika kwamafuta, kusinthasintha kwabwino, komanso zinthu zosamatira kuzinthu zambiri. Mofanana ndi ma PPA a fluoropolymer, ma PPA opangidwa ndi silicone amagwira ntchito posamukira kumalo achitsulo a zipangizo zopangira mafuta kuti apange mafuta odzola.

Mawonekedwe a Ntchito: Ngakhale ma PPA a fluoropolymer ndi omwe amalamulira gawo la polyolefin filimu extrusion, ma PPA opangidwa ndi silikoni amatha kuwonetsa maubwino apadera kapena kupanga mawonekedwe olumikizana akagwiritsidwa ntchito pazinthu zinazake kapena molumikizana ndi makina ena a utomoni. Mwachitsanzo, atha kuganiziridwa ngati ntchito zomwe zimafuna ma coefficients otsika kwambiri a kukangana kapena komwe kufunidwa mawonekedwe amtundu wa chinthu chomaliza.

Kulimbana ndi Kuletsa kwa Fluoropolymer kapena Mavuto Othandizira a PTFE?

Konzani Zovuta Zowonjezera Mafilimu a Polyolefin ndi PFAS-Free PPA Solutions-SILIKE's Fluorine Free Polymer zowonjezera

SILIKE imatenga njira yolimbikitsira ndi zinthu zake za SILIMER, zomwe zimapereka zatsopanoPFAS-free polima processing aids (PPAs). Mzere wathunthu uwu uli ndi 100% ma PPA aulere a PFAS,Fluorine-free PPA Polymer zowonjezera,ndiPFAS-free & fluorine-free PPA masterbatches.Mwakuthetsa kufunikira kwa zowonjezera za fluorine, zothandizira kukonza izi zimakulitsa kwambiri njira yopangira LLDPE, LDPE, HDPE, mLLDPE, PP, ndi njira zosiyanasiyana zotulutsa mafilimu a polyolefin. Amagwirizana ndi malamulo aposachedwa azachilengedwe pomwe amathandiziranso kupanga bwino, kuchepetsa nthawi yopumira, ndikuwongolera zinthu zonse. Ma PPA opanda PFAS a SILIKE amabweretsa zabwino pazogulitsa zomaliza, kuphatikiza kuchotsedwa kwa fracture yosungunuka (chikopa cha shark), kusalala bwino, komanso mawonekedwe apamwamba kwambiri.

Ngati mukulimbana ndi zovuta za kuletsa kwa fluoropolymer kapena kuchepa kwa PTFE munjira zanu za polymer extrusion, SILIKE imaperekam'malo mwa fluoropolymer PPAs/PTFE, Zowonjezera zopanda PFAS zopangira mafilimuzomwe zimapangidwira kuti zikwaniritse zosowa zanu, popanda kusintha kofunikira.