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Intshayelelo kwiPolyolefins kunye neFilm Extrusion

IiPolyolefins, udidi lwezinto ze-macromolecular ezenziwe kwii-olefin monomers ezifana ne-ethylene kunye ne-propylene, zezona plastiki ziveliswa kwaye zisetyenziswa kakhulu kwihlabathi liphela. Ukuxhaphaka kwazo kuvela kudibaniso olukhethekileyo lweempawu, kubandakanya ixabiso eliphantsi, ukucutshungulwa okugqwesileyo, uzinzo olubalaseleyo lweekhemikhali, kunye neempawu zomzimba ezilungelelanisiweyo. Phakathi kwezicelo ezahlukeneyo ze-polyolefins, iimveliso zefilimu zibambe indawo ephambili, zisebenza imisebenzi ebalulekileyo ekupakisheni ukutya, ukugquma kwezolimo, ukupakishwa kwemizi-mveliso, iimveliso zonyango kunye nococeko, kunye neempahla zabathengi zemihla ngemihla. Ii-resin ze-polyolefin eziqhelekileyo ezisetyenziselwa ukuvelisa ifilimu ziquka i-polyethylene (PE) - equka i-Linear Low-Density Polyethylene (LLDPE), i-Low-Density Polyethylene (LDPE), kunye ne-High-Density Polyethylene (HDPE) - kunye ne-polypropylene (PP).

Ukwenziwa kweefilimu ze-polyolefin kuxhomekeke kakhulu kubuchwepheshe bokukhupha, apho i-Blown Film Extrusion kunye ne-Cast Film Extrusion zezona nkqubo zimbini ziphambili.

1. Inkqubo yokukhupha ifilimu evuthayo

Ukukhupha ifilimu evuthuzayo yenye yezona ndlela zixhaphakileyo zokwenza iifilimu ze-polyolefin. Umgaqo osisiseko ubandakanya ukukhupha i-polymer enyibilikisiweyo ngokuthe nkqo phezulu nge-annular die, yenze i-parison yetyhubhu enodonga oluncinci. Emva koko, umoya ocinezelweyo ungeniswa ngaphakathi kweli parison, nto leyo ebangela ukuba ifudumale ibe yi-bubble enobubanzi obukhulu kakhulu kunobo be-die. Njengoko i-bubble inyuka, ipholiswa ngenkani kwaye iqiniswe yiringi yomoya yangaphandle. I-bubble epholileyo emva koko iyadilizwa yiseti yee-nip rollers (ngokudla ngokusebenzisa isakhelo esiwayo okanye i-A-frame) kwaye emva koko itsalwe zii-traction rollers ngaphambi kokuba ibotshelelwe kwi-roll. Inkqubo yefilimu evuthuzayo idla ngokuvelisa iifilimu ezine-biaxial orientation, oko kuthetha ukuba zibonisa ulungelelwano oluhle lweepropati zoomatshini kwicala lomatshini (MD) nakwicala elinqamlezileyo (TD), njengamandla okutsalwa, ukumelana nokukrazula, kunye namandla okubetha. Ubukhulu befilimu kunye neepropati zoomatshini zinokulawulwa ngokulungelelanisa umlinganiselo wokuqhushumba (BUR - umlinganiselo wobubanzi be-bubble ukuya kububanzi bokufa) kunye nomlinganiselo wokutsalwa (DDR - umlinganiselo wesantya sokuthatha ukuya kwisantya sokuphuma).

2. Inkqubo yokukhupha ifilimu

Ukukhupha ifilimu ye-cast yinkqubo ebalulekileyo yokuvelisa iifilimu ze-polyolefin, ezilungele ngokukodwa ukuvelisa iifilimu ezifuna iipropati eziphezulu zokukhanya (umz., ukucaca okuphezulu, ukukhanya okuphezulu) kunye nokufana okugqwesileyo kobukhulu. Kule nkqubo, i-polymer enyibilikisiweyo ikhutshwa ngokuthe tye nge-T-die ethe tyaba, eyenza iwebhu enyibilikisiweyo efanayo. Le webhu emva koko itsalwa ngokukhawuleza kumphezulu we-chill rolls enye okanye ezingaphezulu ezinesantya esiphezulu, ezipholileyo ngaphakathi. Ukunyibilika kuyaqina ngokukhawuleza xa kufikwa kumphezulu we-roll ebandayo. Iifilimu ze-cast zihlala zineempawu ezintle zokukhanya, ukuvakala okuthambileyo, kunye nokuvaleka kakuhle kobushushu. Ulawulo oluchanekileyo phezu kwesithuba se-die lip, ubushushu be-chill roll, kunye nesantya sokujikeleza kuvumela ulawulo oluchanekileyo lobukhulu befilimu kunye nomgangatho womphezulu.

Iingxaki ezi-6 eziphambili zePolyolefin Film Extrusion

Nangona ubuchwepheshe bokukhupha izinto bukhulile, abavelisi bahlala behlangabezana noluhlu lweengxaki zokucubungula imveliso ebonakalayo yeefilimu ze-polyolefin, ingakumbi xa bezama ukuvelisa imveliso ephezulu, ukusebenza kakuhle, ii-thinner gauges, kunye nokusebenzisa ii-resin ezintsha ezisebenza kakuhle. Le micimbi ayichaphazeli nje kuphela uzinzo lwemveliso kodwa ikwachaphazela ngqo umgangatho wemveliso yokugqibela kunye nexabiso. Imingeni ephambili ibandakanya:

1. Ukuqhekeka kweNtlanzi (iSharkskin): Le yenye yezona ziphene zixhaphakileyo kwi-polyolefin film extrusion. Ngokwe-macroscopic, izibonakalisa njengee-ripples ezijikelezayo rhoqo okanye umphezulu ongaqhelekanga kwifilimu, okanye kwiimeko ezinzima, ukugqwetheka okubonakalayo. Ukuqhekeka kweNtlanzi kwenzeka ikakhulu xa izinga lokucheba kwe-polymer melt ephuma kwi-die lidlula ixabiso elibalulekileyo, okukhokelela ekutshibilikeni kwe-stick-slip phakathi kodonga lwe-die kunye nokunyibilika okukhulu, okanye xa uxinzelelo lolwandiso kwi-die exit ludlula amandla okunyibilika. Le ngxaki ichaphazela kakhulu iipropati ze-optical zefilimu (ukucaca, ukukhanya), ukuthamba komphezulu, kwaye inokonakalisa iipropati zayo zoomatshini kunye nezithintelo.

2. Ukwakheka kweDie Drool / Die-up: Oku kubhekiselele ekuqokeleleni kancinci kweemveliso zokubola kwepolymer, iinxalenye ezinobunzima obuphantsi beemolekyuli, izongezo ezisasazeke kakubi (umz., ii-pigment, ii-antistatic agents, ii-slip agents), okanye ii-gels ezivela kwi-resin emaphethelweni emilebe ye-die okanye ngaphakathi kwi-die cavity. Ezi deposits zinokuphuma ngexesha lokuveliswa, zingcolise umphezulu wefilimu kwaye zibangele iziphene ezifana nee-gels, imicu, okanye imikrwelo, ngaloo ndlela zichaphazela imbonakalo kunye nomgangatho wemveliso. Kwiimeko ezinzima, ukwakheka kwe-die kunokuthintela ukuphuma kwe-die, okukhokelela kwiinguqu ze-gauge, ukukrazula kwefilimu, kwaye ekugqibeleni kunyanzelise ukuvalwa kwemigca yemveliso yokucoca i-die, okubangela ilahleko enkulu ekusebenzeni kakuhle kwemveliso kunye nokuchithwa kwezinto eziluhlaza.

3. Uxinzelelo Oluphezulu Lokukhupha Umbane kunye Nokuguquguquka: Phantsi kweemeko ezithile, ingakumbi xa kusetyenzwa iiresini ezine-viscosity ephezulu okanye kusetyenziswa izithuba ezincinci ze-die, uxinzelelo olukwinkqubo ye-extrusion (ingakumbi kwintloko ye-extruder kunye ne-die) lunokuba phezulu kakhulu. Uxinzelelo oluphezulu alunyusi nje kuphela ukusetyenziswa kwamandla kodwa lukwabeka umngcipheko kwixesha elide lezixhobo (umz., isikrufu, ibhere, i-die) kunye nokhuseleko. Ngaphezu koko, ukuguquguquka okungazinzanga kuxinzelelo lwe-extrusion kubangela ngokuthe ngqo utshintsho kwimveliso yokunyibilika, okukhokelela kubukhulu befilimu obungalinganiyo.

4. Ubungakanani boMsebenzi: Ukuthintela okanye ukunciphisa iingxaki ezifana nokuqhekeka kokunyibilika kunye nokwakheka koxinzelelo, abavelisi badla ngokunyanzeleka ukuba banciphise isantya sesikrufu se-extruder, ngaloo ndlela banciphise imveliso yomgca wemveliso. Oku kuchaphazela ngokuthe ngqo ukusebenza kakuhle kwemveliso kunye neendleko zokuvelisa ngeyunithi nganye yemveliso, okwenza kube nzima ukuhlangabezana neemfuno zemarike zeefilimu ezinkulu nezingabizi kakhulu.

5. Ubunzima boLawulo lweGauge: Ukungazinzi ekuhambeni kokunyibilika, ukusasazwa kobushushu obungalinganiyo kwi-die, kunye nokwakheka kwe-die konke oku kunokubangela utshintsho kubukhulu befilimu, kokubini ngokunqamlezayo nangobude. Oku kuchaphazela ukusebenza kwefilimu okulandelayo kunye neempawu zokusetyenziswa kwayo ekugqibeleni.

6. Utshintsho lweResin olunzima: Xa utshintsha phakathi kweentlobo ezahlukeneyo okanye amanqanaba ee-polyolefin resins, okanye xa utshintsha imibala ye-masterbatches, izinto eziseleyo ezivela kumjikelo wangaphambili zihlala kunzima ukuzisusa ngokupheleleyo kwi-extruder kwaye zife. Oku kukhokelela ekudibaneni kwezinto ezindala nezintsha, ukuvelisa izinto zotshintsho, ukwandisa amaxesha okutshintsha, kunye nokunyusa amazinga e-scrap.

Le mingeni ixhaphakileyo yokucubungula ithintela imizamo yabavelisi beefilimu ze-polyolefin yokuphucula umgangatho wemveliso kunye nokusebenza kakuhle kwemveliso, kwaye ikwabeka imiqobo ekwamkelweni kwezixhobo ezintsha kunye neendlela eziphambili zokucubungula. Ke ngoko, ukufuna izisombululo ezisebenzayo zokoyisa le mingeni kubalulekile kuphuhliso oluzinzileyo nolusempilweni lweshishini lonke lokukhupha iifilimu ze-polyolefin.

Izisombululo zeNkqubo yokuKhupha iFilimu yePolyolefin: IiNcedo zokuQhuba iPolymer (iiPPA)

IiPolymer Processing Aids (PPAs) zezongezo ezisebenzayo ezixabiso lazo liphambili ekuphuculeni indlela esebenza ngayo i-rheological ye-polymer melts ngexesha lokukhutshelwa ngaphandle kunye nokutshintsha indlela ezisebenzisana ngayo nezakhiwo zezixhobo, ngaloo ndlela zoyisa ubunzima bokucubungula kunye nokuphucula ukusebenza kakuhle kwemveliso kunye nomgangatho wemveliso.

1. Ii-PPA ezisekelwe kwi-Fluoropolymer

Ulwakhiwo lweeKhemikhali kunye neempawu: Ezi zezona klasi zePPA zisetyenziswa kakhulu, zivuthiweyo kwezobuchwepheshe, kwaye zisebenza ngokubonakalayo. Zihlala ziyi-homopolymers okanye ii-copolymers ezisekelwe kwii-monomers ze-fluoroolefin ezifana ne-vinylidene fluoride (VDF), i-hexafluoropropylene (HFP), kunye ne-tetrafluoroethylene (TFE), kwaye ii-fluoroelastomers zezona zimela kakhulu. Iitsheyini zemolekyuli zezi PPAs zizityebi kwiibhondi ze-CF ezinamandla aphezulu, eziphantsi kwe-polarity, ezinika iipropati ezikhethekileyo ze-physicochemical: amandla aphantsi kakhulu kumphezulu (afana ne-polytetrafluoroethylene/Teflon®), uzinzo oluhle kakhulu lobushushu, kunye nokungangeni kweekhemikhali. Okubalulekileyo kukuba, ii-PPA ze-fluoropolymer zihlala zibonisa ukuhambelana okungekho kakuhle nee-polyolefin matrices ezingezizo ze-polar (ezifana ne-PE, PP). Oku kungahambelani yimfuneko ephambili yokufuduka kwazo ngokufanelekileyo kwiindawo zesinyithi ze-die, apho zenza khona i-dynamic lubricating coating.

Iimveliso Ezimeleyo: Iimpawu eziphambili kwimarike yehlabathi ye-fluoropolymer PPAs ziquka uthotho lweChemours' Viton™ FreeFlow™ kunye nothotho lwe-3M's Dynamar™, olunesabelo esikhulu kwimarike. Ukongeza, amanqanaba athile e-fluoropolymer avela kwi-Arkema (uthotho lweKynar®) kunye ne-Solvay (Tecnoflon®) nawo asetyenziswa njenge, okanye njengezinto eziphambili, kwi-PPA formulations.

2. Izixhobo Zokucubungula Ezisekelwe kwiSilicone (iiPPA)

Ulwakhiwo lweeKhemikhali kunye neempawu: Izinto eziphambili ezisebenzayo kolu didi lwee-PPA zii-polysiloxanes, ezibizwa ngokuba zii-silicones. Umqolo we-polysiloxane uqulathe ii-athomu ze-silicon kunye ne-oxygen (-Si-O-), kunye namaqela e-organic (ngesiqhelo i-methyl) anamathele kwii-athomu ze-silicon. Olu lwakhiwo lwe-molecular lukhethekileyo lunika izixhobo ze-silicone uxinzelelo oluphantsi kakhulu lomphezulu, uzinzo oluhle kakhulu lobushushu, ukuguquguquka okuhle, kunye neempawu ezinganamatheliyo kwizinto ezininzi. Njenge-PPAs ze-fluoropolymer, ii-PPAs ezisekwe kwi-silicone zisebenza ngokufudukela kwiindawo zesinyithi zezixhobo zokucubungula ukuze zenze umaleko wokuthambisa.

Iimpawu zokusetyenziswa: Nangona ii-PPA ze-fluoropolymer zilawula icandelo le-polyolefin film extrusion, ii-PPA ezisekwe kwi-silicone zinokubonisa iingenelo ezikhethekileyo okanye zenze iziphumo ezihambelanayo xa zisetyenziswa kwiimeko ezithile zokusetyenziswa okanye kunye neenkqubo ezithile ze-resin. Umzekelo, zinokuqwalaselwa kwizicelo ezifuna ii-coefficients eziphantsi kakhulu zokungqubana okanye apho iimpawu ezithile zomphezulu zifunwa khona kwimveliso yokugqibela.

Ngaba ujongene nokuthintelwa kweFluoropolymer okanye imingeni yokubonelela ngePTFE?

Sombulula imingeni yePolyolefin Film Extrusion ngezisombululo zePPA zasimahla zePFAS-Izongezo zePolymer ezingenaFluorine zeSILIKE

I-SILIKE isebenzisa indlela yokuthatha amanyathelo ngemveliso zayo zochungechunge lwe-SILIMER, inika izinto ezintshaIzixhobo zokulungisa iipolymer ezingenayo iPFAS (iiPPA)Olu luhlu lwemveliso lubanzi lune-100% ye-PPAS-free PPAS-free PPAS,Izongezo zePolymer zePPA ezingenafluorinekunyeIi-masterbatches ze-PPA ezingenayo i-PFAS kunye ne-fluorine.Nguukuphelisa imfuneko yezongezo ze-fluorine, ezi nkqubo zokucubungula zinceda kakhulu ekuphuculeni inkqubo yokwenziwa kwe-LLDPE, LDPE, HDPE, mLLDPE, PP, kunye neenkqubo ezahlukeneyo zokukhupha ifilimu ye-polyolefin. Zihambelana nemigaqo yamva nje yokusingqongileyo ngelixa zikwaphucula ukusebenza kakuhle kwemveliso, zinciphisa ixesha lokungasebenzi, kwaye ziphucula umgangatho wemveliso iyonke. Ii-PPAs ze-SILIKE ezingenayo i-PFAS zizisa iingenelo kwimveliso yokugqibela, kubandakanya ukususwa kokuqhekeka kwe-melt (isikhumba sooshaka), ukuthamba okuphuculweyo, kunye nomgangatho ophezulu womphezulu.

Ukuba ujongene nempembelelo yokuvalwa kwe-fluoropolymer okanye ukunqongophala kwe-PTFE kwiinkqubo zakho zokukhupha i-polymer, i-SILIKE inikezela ngayo.ezinye iindlela ezingasetyenziswayo endaweni ye-fluoropolymer PPAs/PTFE, Izongezo ezingenayo i-PFAS zokwenza iifilimuezenzelwe ukuhlangabezana neemfuno zakho, kungekho mfuneko yotshintsho lwenkqubo.