Umbhobho (wonkcenkceshelo)

I-polyethylene yoxinaniso oluphezulu, igama lesiNgesi ngu "High Density Polyethylene", okanye "HDPE" ngokufutshane.I-HDPE yintlaka ekhazimle kakhulu, engekho polar ye-thermoplastic resin.Ukubonakala kwe-HDPE yasekuqaleni imhlophe emhlophe, kwaye icandelo elincinci liguquguqukayo ukuya kwinqanaba elithile.I-PE inokumelana okugqwesileyo koninzi lweekhemikhali zasekhaya nezamashishini.Iindidi ezithile zeekhemikhali zinokubangela ukubola kweekhemikhali, ezifana ne-corrosive oxidants (concentrated nitric acid), iihydrocarbons ezinuka kamnandi (xylene) kunye neehalogenated hydrocarbons (carbon tetrachloride).I-polymer ayinayo i-hygroscopic kwaye inokumelana kakuhle nomphunga wamanzi, kwaye ingasetyenziselwa iinjongo zokupakisha.I-HDPE ineempawu ezilungileyo zombane, ngokukodwa amandla aphezulu e-dielectric of the insulation, okwenza ukuba ifaneleke kakhulu iingcingo kunye neentambo.Amabanga aphakathi ukuya kubunzima beemolekyuli aneempembelelo ezigqwesileyo zokuxhathisa, nokuba kubushushu begumbi nakwiqondo lobushushu eliphantsi le--40F.

I-HDPE yi-polyolefin ye-thermoplastic eveliswa yi-copolymerization ye-ethylene.Nangona i-HDPE yasungulwa ngo-1956, le plastiki ayikafikeleli kwinqanaba lokuvuthwa.Esi sixhobo senjongo jikelele sihlala siphuhlisa ukusetyenziswa kwayo okutsha kunye neemarike.

Iimpawu eziphambili

I-HDPE i-non-polar thermoplastic resin ene-crystallinity ephezulu.Ukubonakala kwe-HDPE yasekuqaleni imhlophe emhlophe, kwaye icandelo elincinci liguquguqukayo ukuya kwinqanaba elithile.I-PE inokumelana okugqwesileyo koninzi lweekhemikhali zasekhaya nezamashishini.Iindidi ezithile zeekhemikhali zinokubangela ukubola kweekhemikhali, ezifana ne-corrosive oxidants (concentrated nitric acid), iihydrocarbons ezinuka kamnandi (xylene) kunye neehalogenated hydrocarbons (carbon tetrachloride).I-polymer ayinayo i-hygroscopic kwaye inokumelana kakuhle nomphunga wamanzi, kwaye ingasetyenziselwa iinjongo zokupakisha.I-HDPE ineempawu ezilungileyo zombane, ngokukodwa amandla aphezulu e-dielectric of the insulation, okwenza ukuba ifaneleke kakhulu iingcingo kunye neentambo.Amabanga aphakathi ukuya kubunzima beemolekyuli aneempembelelo ezigqwesileyo zokuxhathisa, nokuba kubushushu begumbi nakwiqondo lobushushu eliphantsi le--40F.Iimpawu ezikhethekileyo zamabakala ahlukeneyo e-HDPE yindibaniselwano efanelekileyo yezinto ezine ezisisiseko: ubuninzi, ubunzima bemolekyuli, ukusabalalisa ubunzima beemolekyuli kunye nezongezo.Ii-catalysts ezahlukeneyo zisetyenziselwa ukuvelisa iipolymers ezenziwe ngokwezifiso ezineempawu ezizodwa.Indibaniselwano yezi zintlukwano ivelisa amabakala e-HDPE ngeenjongo ezahlukeneyo;ukufezekisa eyona ndlela ilungileyo yokusebenza.

ukuxinana

Olu lutshintsho oluphambili olumisela iimpawu ze-HDPE, nangona iinguqu ezine ezikhankanyiweyo zichaphazela omnye nomnye.I-ethylene yeyona nto iphambili ye-polyethylene.Ezinye iicomonomers ezimbalwa, ezifana ne-1-butene, i-1-hexene okanye i-1-octene, nazo zihlala zisetyenziselwa ukuphucula ukusebenza kwe-polymer.Kwi-HDPE, umxholo weemonomers ezimbalwa apha ngasentla awugqithisi kwi-1% -2%.Ukongezwa kwe-comonomer kunciphisa kancinci i-crystallinity yepolymer.Olu tshintsho lulinganiswa ngokubanzi ngoxinaniso, olunobudlelwane bomgca kunye ne-crystallinity.Ukuhlelwa ngokubanzi kwe-United States kuhambelana ne-ASTM D1248, kwaye ubuninzi be-HDPE yi-0.940g /.Ngaphezulu C;Uluhlu loxinaniso lwe-MDPE yi-0.926～0.940g/CC.Olunye ukuhlelwa ngamanye amaxesha luhlela i-MDPE njenge-HDPE okanye i-LLDPE.I-homopolymers inoxinano oluphezulu, ukuqina okuphezulu, ukungeneka okulungileyo kunye neyona ndawo iphezulu yokunyibilika, kodwa ngokubanzi ayinakuxhathisa okungahambi kakuhle kuxinzelelo lwendalo (ESCR).I-ESCR yikhono le-PE lokuchasana nokuqhekeka okubangelwa ngumatshini okanye uxinzelelo lweekhemikhali.Ukuxinana okuphezulu ngokubanzi kuphucula amandla oomatshini, njengamandla okuqina, ukuqina, kunye nobunzima;iipropathi ze-thermal ezifana neqondo lokushisa elithambileyo kunye neqondo lokushisa eliphazamisayo lobushushu;kunye nokungangeni, okufana nokungena komoya okanye umphunga wamanzi.Uxinzelelo olusezantsi luphucula amandla ayo empembelelo kunye ne-E-SCR.Uxinaniso lwepolymer luchaphazeleka ikakhulu kukongezwa kweecomonomers, kodwa kuncinci ngobunzima bemolekyuli.Ipesenteji yobunzima bemolekyuli ephezulu inciphisa ukuxinana kancinci.Ngokomzekelo, ii-homopolymers zineendidi ezahlukeneyo kuluhlu olubanzi lobunzima beemolekyuli.

Imveliso kunye ne-catalyst

Eyona ndlela iqhelekileyo yokuvelisa i-PE kukusetyenzwa kwe-slurry okanye i-gas phase, kwaye ezimbalwa ziveliswa ngokulungiswa kwesigaba sesisombululo.Zonke ezi nkqubo zii-exothermic reactions ezibandakanya i-ethylene monomer, i-a-olefin monoma, inkqubo ye-catalyst (inokuba ngaphezu kwekhompawundi enye) kunye neentlobo ezahlukeneyo ze-hydrocarbon diluents.I-Hydrogen kunye nezinye ii-catalysts zisetyenziselwa ukulawula ubunzima be-molecular.Ireactor yodaka oluludaka ludla ngokuba yitanki eshukumayo okanye ireactor esetyenziswa ngokuqhelekileyo kwilophu enkulu apho udaka lunokujikeleziswa kwaye lushukunyiswe.Xa i-ethylene kunye ne-comonomer (njengoko kuyimfuneko) zidibana ne-catalyst, iinqununu ze-polyethylene zenziwe.Emva kokususa i-diluent, i-polyethylene granules okanye i-powder granules iyomiswa kwaye izongezo zongezwa ngokwe-dosage ukuvelisa iipelisi.Umgca wemveliso yanamhlanje kunye ne-reactors enkulu kunye ne-twin screw extruders inokuvelisa ngaphezu kwe-40,000 yeepounds ze-PE ngeyure.Ukuphuhliswa kwee-catalysts ezintsha kunegalelo ekuphuculeni ukusebenza kwamabanga amatsha e-HDPE.Iintlobo ezimbini ezisetyenziswa ngokuqhelekileyo ze-catalysts yi-Philips' chromium oxide-based catalysts kunye ne-titanium compound-alkyl aluminium catalysts.I-HDPE eveliswe yi-Phillips catalyst ine-medium-width-width molecular weight distribution;i-titanium-alkyl aluminium catalyst inokusabalalisa ubunzima bemolekyuli.I-catalyst esetyenziselwa ukuveliswa kweepolymers ze-MDW emxinwa kwi-reactor ephindwe kabini ingasetyenziselwa ukuvelisa amabakala abanzi e-MDW.Umzekelo, ii-reactors ezimbini kuthotho ezivelisa iimveliso ezinobunzima bemolekyuli ezahlukeneyo zinokuvelisa iipolymers ze-bimodal molecular weight ezinoluhlu olupheleleyo lolwabiwo lobunzima bemolekyuli.Ukufakwa kombhobho we-PE

Ubunzima bemolekyuli

Ubunzima obuphezulu bemolekyuli buphumela kwi-polymer viscosity ephezulu, kodwa i-viscosity ikwanxulumene nobushushu kunye nesantya sokucheba esisetyenziswa kuvavanyo.I-Rheology okanye i-molecular weight measurement isetyenziselwa ukubonakalisa ubunzima be-molecular of the material.Amabakala e-HDPE ngokubanzi anobunzima bobunzima be-molecular 40 000 ukuya ku-300 000, kunye ne-avareji yobunzima be-molecular weight ngokumalunga ne-melt index range, oko kukuthi, ukusuka kwi-100 ukuya ku-0. 029/10min.Ngokubanzi, i-MW ephezulu (i-Lower melt index MI) yongeza amandla okunyibilika, ukuqina okungcono kunye ne-ESCR, kodwa i-MW ephezulu yenza ukusetyenzwa.

Inkqubo inzima ngakumbi okanye idinga uxinzelelo oluphezulu okanye ubushushu.

Ukusabalalisa ubunzima be-molecular (MWD): I-WD ye-PE iyahluka ukusuka kumxinwa ukuya kububanzi ngokuxhomekeke kwi-catalyst esetyenzisiweyo kunye nenkqubo yokucubungula.

Eyona isetyenziswa ngokuqhelekileyo isalathisi somlinganiselo we-MWD yi-inevenness index (HI), elingana ne-avareji yobunzima bobunzima bemolekyuli (MW) yahlulwe ngenani eliphakathi kobunzima bemolekyuli (Mn).Olu luhlu lwesalathisi kuwo onke amabakala e-HDPE yi-4-30.I-MWD emxinwa ibonelela nge-warpage ephantsi kunye nefuthe eliphezulu ngexesha lenkqubo yokubumba.I-MWD ephakathi ukuya kububanzi ibonelela ngokuqhubekeka kwezona nkqubo zininzi ze-extrusion.I-WD ebanzi ingaphucula amandla okunyibilika kunye nokuxhathisa kokurhubuluza.

ukongeza

Ukongezwa kwe-antioxidants kunokuthintela ukuthotywa kwepolymer ngexesha lokucubungula kunye nokuthintela i-oxidation yemveliso egqityiweyo ngexesha lokusetyenziswa.Izongezo ze-Antistatic zisetyenziselwa amabakala amaninzi okupakisha ukunciphisa ukunamathela kwiibhotile okanye ukupakisha uthuli kunye nokungcola.Izicelo ezikhethekileyo zifuna iifomyula ezikhethekileyo ezongezelelweyo, ezifana ne-copper inhibitors ezinxulumene nocingo kunye nezicelo zekhebula.Ukumelana nemozulu egqwesileyo kunye ne-anti-ultraviolet (okanye ukukhanya kwelanga) kunokufezekiswa ngokungeza izongezo ze-anti-UV.Ngaphandle kokongezwa kwe-UV-resistant okanye i-carbon black PE, kuyacetyiswa ukuba ungaqhubeki ukuyisebenzisa ngaphandle.Umgangatho ophezulu we-carbon pigment emnyama ibonelela ngokugqwesileyo kwi-UV kwaye ihlala isetyenziswa kwizicelo zangaphandle, ezinje ngeengcingo, iintambo, iileya zetanki okanye imibhobho.

iindlela zokulungisa

I-PE inokuveliswa kuluhlu olubanzi lweendlela ezahlukeneyo zokucwangcisa.Ukusebenzisa i-ethylene njengeyona nto iphambili, i-propylene, i-1-butene, kunye ne-hexene njenge-copolymer, phantsi kwesenzo se-catalyst, inkqubo ye-polymerization ye-slurry okanye i-gas phase polymerization iyamkelwa, kwaye i-polymer efunyenweyo iyavutha, ihlukaniswe, yomiswe, igranulated. , njl Inkqubo yokufumana iimveliso ezigqityiweyo kunye neengqungquthela ezifanayo.Kubandakanywa ezifana ne-sheet extrusion, ifilimu extrusion, umbhobho okanye iprofayili extrusion, ukubumba ukuvuthela, ukubunjwa kwenaliti kunye nokubumba okujikelezayo.

▲I-Extrusion: Ibakala elisetyenziselwa imveliso ye-extrusion ngokubanzi inesalathisi esinyibilikayo esingaphantsi kwe-1 kunye ne-MWD ephakathi ukuya kububanzi.Ngexesha lokucubungula, i-MI ephantsi inokufumana amandla afanelekileyo anyibilikayo.Amabanga abanzi e-MWD afaneleke ngakumbi kwi-extrusion ngenxa yokuba anezantya eziphezulu zemveliso, uxinzelelo olusezantsi lokufa kunye nokuncitshiswa kokuthambekela kokuqhekeka kokunyibilika.

I-PE inezicelo ezininzi ze-extrusion, ezifana neengcingo, iintambo, i-hoses, imibhobho kunye neeprofayili.Ukusetyenziswa kwemibhobho ukusuka kwimibhobho etyheli yecandelo elincinci yerhasi yendalo ukuya kwimibhobho emnyama eneendonga ezingqindilili enobubanzi obungama-48in kwimibhobho yemizi-mveliso neyedolophu.Ukusetyenziswa kwemibhobho yodonga olunomngxuma omkhulu enobubanzi njengendawo ebambela imibhobho yokuhambisa amanzi emvula eyenziwe ngekhonkrithi neminye imibhobho yogutyulo ikhula ngokukhawuleza.

Iphepha kunye ne-thermoforming: I-thermoforming lining yeefriji ezininzi ezinkulu zepikiniki zenziwe nge-PE, eqinile, ilula kwaye ihlala ixesha elide.Amanye amaphepha kunye neemveliso ze-thermoformed ziquka udaka, ii-tank liners, iipani zokugada, iibhokisi zokuthumela kunye neetanki.Inani elikhulu lezicelo ze-sheet ezikhula ngokukhawuleza ziyi-mulch okanye iilali ezisezantsi zamachibi, ezisekelwe kukuqina, ukuxhathisa imichiza kunye nokunganyanzeki kwe-MDPE.

▲ Ukubumba ukuvuthela: Ngaphezu kwe-1/3 ye-HDPE ethengiswa e-United States isetyenziselwa ukubumba ukuvuthela.Ezi bhotile zisusela kwiibhotile ezinebleach, i-oyile yemoto, isicoci, ubisi kunye namanzi adiyiweyo ukuya kwizikhenkcisi ezinkulu, iitanki zamafutha emoto kunye neetoti.Iimpawu zokubumba amabakala, njengamandla okunyibilika, i-ES-CR kunye nokuqina, zifana nezo zisetyenziselwa izicelo zephepha kunye ne-thermoforming, ngoko ke amabakala afanayo angasetyenziswa.

I-injection-blolow molding idla ngokusetyenziselwa ukwenza izikhongozeli ezincinci (ngaphantsi kwe-16oz) zokupakisha amayeza, iishampu kunye nezinto zokuthambisa.Enye yeenzuzo zale nkqubo kukuba iibhotile zokuvelisa zihlanjululwa ngokuzenzekelayo, ngaphandle kwemfuneko yamanyathelo okugqiba emva kokugqiba njengokubumba ngokubanzi.Nangona amanye amabakala emxinwa e-MWD esetyenziselwa ukuphucula umphezulu wokugqiba, amabanga aphakathi ukuya kububanzi be-MWD asetyenziswa ngokubanzi.

▲ I-injection molding: I-HDPE inezicelo ezingenakubalwa, ukusuka kwiikomityi zesiselo esincinci-esibiyelweyo ukuya kwi-5-gsl iinkonkxa, ezidla i-1/5 ye-HDPE yasekhaya.Amabakala okubumba isitofu ngokubanzi anesalathiso sokunyibilika kwe-5-10.Kukho amabakala anokuqina kunye nokungaguquguquki okusezantsi kunye namabakala aphezulu okuguquguquka nokuqhubekeka.Usetyenziso lubandakanya iimfuno zemihla ngemihla kunye nokutya okupakishwe ngodonga olucekethekileyo;ukutya okuqinileyo kunye neetoti zepeyinti;ukuchasana okuphezulu kwizicelo zokuqhekeka koxinzelelo lwendalo, njengamatanki e-injini amancinci kunye ne-90-gal yenkunkuma.

▲ Ukubumba okujikelezayo: Izinto ezisebenzisa le ndlela yokucubungula zityunyuzwa ngokubanzi zibe ngumgubo, ezinyibilikayo kwaye zihambe kumjikelo we-thermal.I-Rotomolding isebenzisa iindidi ezimbini ze-PE: injongo-jikelele kunye ne-cross-linkable.Injongo ngokubanzi ye-MDPE / HDPE ngokuqhelekileyo inobuninzi obuvela kwi-0.935 ukuya kwi-0.945g / CC, kunye ne-MWD encinci, ukwenzela ukuba imveliso ibe nefuthe eliphezulu kunye ne-warpage encinci, kwaye isalathisi sayo sokunyibilika ngokuqhelekileyo kuluhlu lwe-3-8.Amabakala aphezulu e-MI awafanelekanga ngenxa yokuba awanayo impembelelo kunye noxinzelelo lokusingqongileyo ukumelana nokuqhekeka okulindelekileyo kwiimveliso ze-rotomolded.

Ukusetyenziswa kokubumba okujikelezayo okusebenzayo okuphezulu kusebenzisa iipropathi ezikhethekileyo zamabakala ayo anqamlezileyo ngokwekhemikhali.Ezi bakala zine-fluidity elungileyo kwinxalenye yokuqala yomjikelo wokubumba, kwaye emva koko i-crosslink ukwenza imo ebalaseleyo yokuchasana noxinzelelo lokusingqongileyo kunye nokuqina.Ukumelana nokunxiba kunye nokumelana nemozulu.I-Cross-linkable PE ifanelekile kuphela kwizikhongozeli ezinkulu, ukusuka kwi-500-gal tanks zokuthutha iikhemikhali ezahlukeneyo ukuya kwi-20,000-gal tanks yezolimo.

▲Ifilimu: Ukusetyenzwa kwefilimu ye-PE ngokuqhelekileyo kusebenzisa inkqubo yefilimu evuthelweyo eqhelekileyo okanye ukusetyenzwa kweflethi.Uninzi lwe-PE lusetyenziselwa ifilimu, i-PE (LDPE) ye-low-density PE (LDPE) okanye i-linear low-density PE (LLDPE) iyafumaneka.Amanqanaba efilimu ye-HDPE asetyenziswa ngokubanzi apho ukunwebeka okuphezulu kunye nokunganyanzeki okugqwesileyo kuyadingeka.Umzekelo, ifilimu ye-HDPE isoloko isetyenziselwa iingxowa zempahla, iingxowa zegrosari kunye nokupakishwa kokutya.

Ukusebenza kwemveliso

I-polyethylene ephezulu yoxinaniso ayinayo ityhefu, ayinambitheki, kwaye ayinavumba, kwaye ayinavumba elimhlophe elinendawo yokunyibilika malunga ne-130 ° C kunye nokuxinana kwe-0.941 kwi-0.960.Inokumelana nobushushu obuhle kunye nokumelana nokubanda, ukuzinza okulungileyo kweekhemikhali, ukuqina okuphezulu kunye nokuqina, kunye namandla afanelekileyo omatshini.Iipropathi zeDielectric kunye noxinzelelo lokusingqongileyo ukuchasana nokuqhekeka nazo zilungile.

Ukupakishwa kunye nokugcinwa

Gcina kude nomlilo kunye nokugquma ubushushu ngexesha lokugcina.Indawo yokugcina impahla kufuneka igcinwe yomile kwaye icocekile.Kuvinjelwe ngokungqongqo ukuxuba nakuphi na ukungcola, ukukhanya kwelanga kunye nemvula.Izithuthi kufuneka zigcinwe kwiikhareji ezicocekileyo, ezomileyo, ezigqunyiweyo okanye kwiikhabhathi, kwaye kungabikho zinto zibukhali njengezikhonkwane zentsimbi.Uthutho oluxutyiweyo kunye neehydrocarbons ezinevumba elimnandi, iihalogenated hydrocarbons kunye nezinye izinyibilikisi eziphilayo azivumelekanga ngokungqongqo.

ukuhlaziya nokusebenzisa kwakhona

I-HDPE yeyona ndawo ikhula ngokukhawuleza kwimarike yokwenziwa ngokutsha kweplastiki.Oku kungenxa yokulungiswa kwayo ngokulula, iimpawu zokuthotywa okuncinci kunye nenani elikhulu lezicelo zeenjongo zokupakisha.Eyona nto iphambili yokurisayikilishwa kukuhlaziya kwakhona i-25% yezinto ezisetyenzisiweyo, ezifana ne-post-consumer recyclables (PCR), ngeHDPE esulungekileyo ukwenza iibhotile ezingadibaniyo nokutya.

Imibhobho ye-PE yonikezelo lwamanzi yimveliso yokutshintshwa kwemibhobho yentsimbi yemveli kunye nemibhobho yamanzi okusela ye-PVC.