Chitoliro ( cha Irrigation)

Polyethylene yochuluka kwambiri, dzina la Chingerezi ndi "High Density Polyethylene", kapena "HDPE" mwachidule.HDPE ndi utomoni wonyezimira kwambiri, wopanda polar thermoplastic resin.Maonekedwe a HDPE yoyambirira ndi yoyera yamkaka, ndipo gawo lopyapyala limatuluka pang'onopang'ono.PE imatsutsana kwambiri ndi mankhwala ambiri apanyumba ndi mafakitale.Mitundu ina yamankhwala imatha kuwononga dzimbiri, monga ma corrosive oxidants (concentrated nitric acid), ma hydrocarbon onunkhira (xylene) ndi ma halogenated hydrocarbon (carbon tetrachloride).Polima si hygroscopic ndipo imakhala ndi mpweya wabwino wamadzi, ndipo imatha kugwiritsidwa ntchito pakuyika.HDPE ili ndi mphamvu zamagetsi zamagetsi, makamaka mphamvu yayikulu ya dielectric yotsekera, zomwe zimapangitsa kuti zikhale zoyenera kwambiri pamawaya ndi zingwe.Magiredi apakati mpaka apamwamba kwambiri a maselo amakhala ndi kukana kwambiri, ngakhale kutentha kwa firiji komanso ngakhale kutentha kwa -40F.

HDPE ndi thermoplastic polyolefin yopangidwa ndi copolymerization ya ethylene.Ngakhale HDPE idakhazikitsidwa mu 1956, pulasitiki iyi sinafike pamlingo wokhwima.Zomwe zimagwiritsidwa ntchito nthawi zonse zimapanga ntchito zatsopano komanso misika.

Mbali zazikulu

HDPE ndi utomoni wopanda polar thermoplastic wokhala ndi crystallinity yayikulu.Maonekedwe a HDPE yoyambirira ndi yoyera yamkaka, ndipo gawo lopyapyala limatuluka pang'onopang'ono.PE imatsutsana kwambiri ndi mankhwala ambiri apanyumba ndi mafakitale.Mitundu ina yamankhwala imatha kuwononga dzimbiri, monga ma corrosive oxidants (concentrated nitric acid), ma hydrocarbon onunkhira (xylene) ndi ma halogenated hydrocarbon (carbon tetrachloride).Polima si hygroscopic ndipo imakhala ndi mpweya wabwino wamadzi, ndipo imatha kugwiritsidwa ntchito pakuyika.HDPE ili ndi mphamvu zamagetsi zamagetsi, makamaka mphamvu yayikulu ya dielectric yotsekera, zomwe zimapangitsa kuti zikhale zoyenera kwambiri pamawaya ndi zingwe.Magiredi apakati mpaka apamwamba kwambiri a maselo amakhala ndi kukana kwambiri, ngakhale kutentha kwa firiji komanso ngakhale kutentha kwa -40F.Makhalidwe apadera a magiredi osiyanasiyana a HDPE ndi kuphatikiza koyenera kwa mitundu inayi yoyambira: kachulukidwe, kulemera kwa mamolekyulu, kugawa kulemera kwa maselo ndi zowonjezera.Zothandizira zosiyanasiyana zimagwiritsidwa ntchito kupanga ma polima makonda okhala ndi zinthu zapadera.Kuphatikiza kwa mitundu iyi kumatulutsa magiredi a HDPE pazifukwa zosiyanasiyana;kupeza bwino bwino pakuchita bwino.

kachulukidwe

Uwu ndiye kusintha kwakukulu komwe kumatsimikizira mawonekedwe a HDPE, ngakhale zosintha zinayi zomwe zatchulidwa zimakhudzana.Ethylene ndiye chopangira chachikulu cha polyethylene.Ma comonomers ena ochepa, monga 1-butene, 1-hexene kapena 1-octene, amagwiritsidwanso ntchito kupititsa patsogolo magwiridwe antchito a polima.Kwa HDPE, zomwe zili m'ma monomer ochepa pamwambapa nthawi zambiri sizidutsa 1% -2%.Kuwonjezera kwa comonomer kumachepetsa pang'ono crystallinity ya polima.Kusintha kumeneku kumayesedwa ndi kachulukidwe, komwe kumakhala ndi ubale wofananira ndi crystallinity.Magulu onse a United States ali molingana ndi ASTM D1248, ndipo kachulukidwe ka HDPE ndi 0.940g/.Pamwamba C;Kuchulukana kwa MDPE ndi 0.926 ~ 0.940g/CC.Zigawo zina nthawi zina zimayika MDPE ngati HDPE kapena LLDPE.Ma homopolymers ali ndi kachulukidwe kwambiri, kuuma kwambiri, kutsekemera bwino komanso malo osungunuka kwambiri, koma nthawi zambiri amakhala osakanizidwa ndi kuwonongeka kwa chilengedwe (ESCR).ESCR ndi kuthekera kwa PE kukana kusweka komwe kumachitika chifukwa cha kupsinjika kwamakina kapena mankhwala.Kuchulukana kwakukulu kumawonjezera mphamvu zamakina, monga kulimba kwamphamvu, kuuma, ndi kuuma;kutentha katundu monga kufewetsa mfundo kutentha ndi kutentha kupotoza kutentha;ndi kusalolera, monga mpweya permeability kapena madzi nthunzi permeability.Kachulukidwe kakang'ono kamawonjezera mphamvu zake komanso E-SCR.Kuchuluka kwa ma polima kumakhudzidwa makamaka ndi kuwonjezera kwa ma comonomers, koma pang'ono ndi kulemera kwa maselo.Kulemera kwakukulu kwa maselo kumachepetsa kachulukidwe pang'ono.Mwachitsanzo, ma homopolymers ali ndi kachulukidwe kosiyanasiyana pamiyeso yambiri yama cell.

Kupanga ndi chothandizira

Njira yodziwika kwambiri yopangira PE ndikugwiritsa ntchito slurry kapena gasi gawo, ndipo ochepa amapangidwa ndi njira yothetsera.Zonsezi ndi zochita exothermic zokhudza ethylene monoma, a-olefin monoma, chothandizira dongosolo (akhoza kukhala oposa pawiri) ndi mitundu yosiyanasiyana ya hydrocarbon diluents.Hydrogen ndi zopangira zina zimagwiritsidwa ntchito kuwongolera kulemera kwa maselo.The slurry reactor nthawi zambiri imakhala thanki yogwedezeka kapena chojambulira chomwe chimagwiritsidwa ntchito kwambiri pomwe matope amatha kuzunguliridwa ndikugwedezeka.Pamene ethylene ndi comonomer (monga kufunikira) kukumana ndi chothandizira, polyethylene particles amapangidwa.Pambuyo pochotsa diluent, ma polyethylene granules kapena ma granules a ufa amawumitsidwa ndipo zowonjezera zimawonjezeredwa molingana ndi mlingo kuti apange pellets.Mzere wamakono wopanga wokhala ndi ma reactors akulu okhala ndi ma screw extruders amatha kutulutsa mapaundi opitilira 40,000 a PE pa ola limodzi.Kupanga zida zatsopano kumathandizira kukonza magwiridwe antchito a HDPE.Mitundu iwiri ya zothandizira zomwe zimagwiritsidwa ntchito kwambiri ndi Philips' chromium oxide-based catalysts ndi titanium compound-alkyl aluminium catalysts.HDPE yopangidwa ndi chothandizira cha Phillips ili ndi kugawa kwapang'onopang'ono kwa maselo;titaniyamu-alkyl aluminiyamu chothandizira ali ndi yopapatiza molecular kulemera kugawa.Chothandizira ntchito kupanga yopapatiza ma polima MDW mu riyakitala wapawiri Angagwiritsidwenso ntchito kubala lonse MDW sukulu.Mwachitsanzo, ma reactors awiri mu mndandanda omwe amapanga zinthu zolemetsa kwambiri zama cell amatha kupanga ma polima olemera a bimodal molekyulu omwe ali ndi magawo osiyanasiyana azinthu zolemetsa.Zida za PE

Kulemera kwa maselo

Kulemera kwa mamolekyulu apamwamba kumabweretsa kukhuthala kwa polymer, koma kukhuthala kumagwirizananso ndi kutentha ndi kumeta ubweya komwe kumagwiritsidwa ntchito poyesa.Rheology kapena kuyeza kulemera kwa mamolekyulu kumagwiritsidwa ntchito kuwonetsa kulemera kwa zinthuzo.Magiredi a HDPE nthawi zambiri amakhala ndi kulemera kwa ma molekyulu a 40 000 mpaka 300 000, ndipo kulemera kwake kwa molekyulu pafupifupi kumafanana ndi mtundu wa melt index, ndiko kuti, kuyambira 100 mpaka 0. 029/10min.Nthawi zambiri, kuchuluka kwa MW (Lower melt index MI) kumawonjezera mphamvu yosungunuka, kulimba kwabwinoko ndi ESCR, koma MW wapamwamba umapangitsa kuti ntchitoyo ikhale yolimba.

Njirayi ndi yovuta kwambiri kapena imafuna kuthamanga kwakukulu kapena kutentha.

Kugawa kulemera kwa mamolekyulu (MWD): WD ya PE imasiyanasiyana kuchokera ku yopapatiza kupita kumtunda kutengera chothandizira chomwe chimagwiritsidwa ntchito komanso momwe amapangira.

Mlozera woyezera wa MWD womwe umagwiritsidwa ntchito kwambiri ndi unevenness index (HI), womwe ndi wofanana ndi kulemera kwa molekyulu ya molekyulu (MW) yogawidwa ndi kuchuluka kwa kulemera kwa molekyulu (Mn).Mndandanda uwu wamagulu onse a HDPE ndi 4-30.The yopapatiza MWD amapereka otsika warpage ndi zotsatira mkulu pa akamaumba ndondomeko.The sing'anga ndi lonse MWD amapereka processability njira zambiri extrusion.Wide MWD imathanso kupititsa patsogolo kusungunuka kwamphamvu komanso kukana kukwawa.

chowonjezera

Kuphatikizika kwa ma antioxidants kumatha kuletsa kuwonongeka kwa polima panthawi yokonza ndikuletsa oxidation ya chinthu chomwe chamalizidwa pakagwiritsidwa ntchito.Zowonjezera za antistatic zimagwiritsidwa ntchito m'makalasi ambiri onyamula kuti achepetse kumamatira kwa mabotolo kapena kuyika ku fumbi ndi dothi.Mapulogalamu apadera amafunikira zowonjezera zowonjezera, monga zoletsa zamkuwa zokhudzana ndi mawaya ndi zingwe.Kukana kwanyengo kwabwino kwambiri komanso anti-ultraviolet (kapena kuwala kwa dzuwa) kutha kupezedwa powonjezera zowonjezera zotsutsana ndi UV.Popanda kuwonjezera kwa UV-resistant kapena carbon black PE, tikulimbikitsidwa kuti musapitirize kuigwiritsa ntchito panja.Mitundu yapamwamba kwambiri ya carbon black pigment imapereka kukana kwa UV ndipo nthawi zambiri imagwiritsidwa ntchito panja, monga mawaya, zingwe, zigawo za tanki kapena mapaipi.

processing njira

PE ikhoza kupangidwa m'njira zosiyanasiyana.Kugwiritsa ntchito ethylene monga zopangira zazikulu, propylene, 1-butene, ndi hexene monga copolymer, pansi pa zochita za chothandizira, slurry polymerization kapena mpweya gawo polymerization ndondomeko anatengera, ndipo analandira polima zimawalira, olekanitsidwa, zouma, granulated. , etc. Njira yopezera zinthu zomalizidwa ndi tinthu tating'onoting'ono.Kuphatikizapo monga pepala extrusion, filimu extrusion, chitoliro kapena mbiri extrusion, kuwomba akamaumba, jekeseni akamaumba ndi rotational akamaumba.

▲ Extrusion: Magiredi omwe amagwiritsidwa ntchito popanga extrusion nthawi zambiri amakhala ndi index yosungunuka yochepera 1 ndi MWD yapakatikati ndi yayikulu.Panthawi yokonza, MI yotsika imatha kupeza mphamvu zosungunuka.Magiredi okulirapo a MWD ndi oyenera kutulutsa chifukwa ali ndi liwiro lokwera kwambiri, kutsika kwapang'onopang'ono kwa kufa komanso kuchepa kwa kusungunuka kwa fracture.

PE ili ndi ntchito zambiri zowonjezera, monga mawaya, zingwe, hoses, mapaipi ndi mbiri.Ntchito zamapaipi zimayambira pazipaipi zazing'ono zachikasu za gasi wachilengedwe mpaka mapaipi akuda okhala ndi mipanda yakuda okhala ndi mainchesi 48 pamapaipi a mafakitale ndi akumatauni.Kugwiritsiridwa ntchito kwa mipope ya m’mipaipi ikuluikulu ya m’mabowo monga m’malo mwa mipope ya madzi amvula yopangidwa ndi konkire ndi mipopi ina ya zonyansa ikukula mofulumira.

Mapepala ndi thermoforming: Thermoforming ya mafiriji ambiri akuluakulu amapikiniki amapangidwa ndi PE, yomwe ndi yolimba, yopepuka komanso yolimba.Zogulitsa zina zokhala ndi mapepala ndi thermoformed ndi monga oteteza matope, zomangira akasinja, alonda apapan, mabokosi otumizira ndi akasinja.Mapepala ambiri omwe akukula mofulumira ndi midzi ya mulch kapena dziwe pansi pa dziwe, yomwe imachokera ku kulimba, kukana kwa mankhwala ndi kusasunthika kwa MDPE.

▲Kuwomba: Kupitilira 1/3 ya HDPE yogulitsidwa ku United States imagwiritsidwa ntchito popanga nkhonya.Izi zimachokera ku mabotolo okhala ndi bulichi, mafuta agalimoto, zotsukira, mkaka ndi madzi osungunuka mpaka mafiriji akulu, matanki amafuta amgalimoto ndi zitini.Makhalidwe a kalasi yowomba, monga kusungunuka kwamphamvu, ES-CR ndi kulimba, ndizofanana ndi zomwe zimagwiritsidwa ntchito pamapepala ndi ma thermoforming, kotero magiredi ofanana angagwiritsidwe ntchito.

Kumangira jekeseni nthawi zambiri kumagwiritsidwa ntchito popanga zotengera zing'onozing'ono (zosakwana 16oz) zopangira mankhwala, ma shampoos ndi zodzoladzola.Ubwino wina wa njirayi ndikuti mabotolo opangira amangokonzedwa, popanda kufunikira komaliza monga kuumba kwapang'onopang'ono.Ngakhale magiredi ena opapatiza a MWD amagwiritsidwa ntchito kupititsa patsogolo kutha kwapamwamba, magiredi apakati mpaka otakata a MWD amagwiritsidwa ntchito.

▲ Jekeseni akamaumba: HDPE ali ntchito zosawerengeka, kuyambira reusable makapu zakumwa woonda-mipanda mpaka 5-gsl zitini, amene amadya 1/5 HDPE zoweta.Makalasi opangira jakisoni nthawi zambiri amakhala ndi index yosungunuka ya 5-10.Pali magiredi okhala ndi kulimba komanso kutsika kwamadzimadzi komanso magiredi apamwamba kwambiri okhala ndi processability.Zogwiritsidwa ntchito zimaphatikizapo zofunikira za tsiku ndi tsiku ndi zakudya zopangira mipanda yopyapyala;chakudya cholimba komanso chokhalitsa ndi zitini za penti;kukana kwambiri kupsinjika kwa chilengedwe, monga matanki amafuta a injini yaing'ono ndi zinyalala za 90-gal.

▲Kumangirira mozungulira: Zida zomwe zimagwiritsidwa ntchito pokonza izi nthawi zambiri zimaphwanyidwa kukhala zida zaufa, zomwe zimasungunuka ndikuyenda mumayendedwe otentha.Rotomolding amagwiritsa ntchito mitundu iwiri ya PE: general-purpose and cross-linkable.General-purpose MDPE/HDPE nthawi zambiri imakhala ndi kachulukidwe koyambira 0.935 mpaka 0.945g/CC, yokhala ndi MWD yopapatiza, kotero kuti mankhwalawa amakhala ndi mphamvu yayikulu komanso yocheperako, ndipo index yake yosungunuka imakhala pakati pa 3-8.Magiredi apamwamba a MI nthawi zambiri sakhala oyenera chifukwa alibe mphamvu komanso kukana kupsinjika kwa chilengedwe komwe kumayembekezeredwa ndi zinthu zopangidwa ndi rotomold.

Mapangidwe apamwamba ozungulira amagwiritsira ntchito mawonekedwe apadera amagulu ake osakanikirana ndi mankhwala.Maphunzirowa amakhala ndi madzi abwino mu gawo loyamba la kuumbika, ndiyeno crosslink kuti apange kulimba kwawo kwamphamvu kwa chilengedwe komanso kulimba mtima.Valani kukana ndi kukana nyengo.Cross-linkable PE ndiyoyenera kutengera zotengera zazikulu, kuyambira matanki a 500-gal onyamula mankhwala osiyanasiyana kupita ku matanki aulimi a 20,000.

▲Filimu: Kukonza filimu ya PE nthawi zambiri kumagwiritsa ntchito filimu yowombedwa wamba kapena kutulutsa kosalala.PE yambiri imagwiritsidwa ntchito pafilimu, general low-density PE (LDPE) kapena linear low-density PE (LLDPE) ilipo.Makanema amakanema a HDPE nthawi zambiri amagwiritsidwa ntchito pomwe kutanuka kwapamwamba komanso kusakwanira bwino kumafunika.Mwachitsanzo, filimu ya HDPE nthawi zambiri imagwiritsidwa ntchito popanga matumba azinthu, matumba a golosale ndi kulongedza zakudya.

Zochita zamalonda

Polyethylene yochuluka kwambiri ndi yopanda poizoni, yopanda fungo, komanso yopanda fungo ndipo imasungunuka pafupifupi 130 ° C ndi kachulukidwe ka 0.941 mpaka 0.960.Ili ndi kukana kwabwino kwa kutentha ndi kukana kuzizira, kukhazikika kwamankhwala abwino, kukhazikika kwakukulu komanso kulimba, komanso mphamvu zamakina.Katundu wa dielectric komanso kukana kupsinjika kwa chilengedwe ndikwabwino.

Kupaka ndi kusunga

Pewani kutenthetsa moto ndi kutentha panthawi yosungira.Malo osungiramo zinthu ayenera kukhala owuma komanso aukhondo.Ndizoletsedwa kusakaniza mu zonyansa zilizonse, kuwala kwa dzuwa ndi mvula.Zoyendera ziyenera kusungidwa m'ngolo zaukhondo, zowuma, zophimbidwa kapena m'nyumba, ndipo pasakhale zinthu zakuthwa monga misomali yachitsulo.Kuyendera kosakanikirana ndi ma hydrocarbon onunkhira oyaka, ma halogenated hydrocarbons ndi zosungunulira zina za organic ndizoletsedwa.

konzanso ndikugwiritsanso ntchito

HDPE ndiye gawo lomwe likukula mwachangu pamsika wobwezeretsanso pulasitiki.Izi makamaka chifukwa cha kukonzanso kwake kosavuta, mawonekedwe ake ocheperako komanso kuchuluka kwake kwa ntchito zopangira ma CD.Chobwezeretsanso chachikulu ndikukonzanso 25% ya zinthu zobwezerezedwanso, monga post-consumer recyclables (PCR), ndi HDPE yoyera kuti apange mabotolo omwe sakukhudzana ndi chakudya.

Mapaipi a PE operekera madzi ndi omwe amasinthidwa ndi mapaipi achitsulo achikhalidwe ndi mapaipi amadzi akumwa a PVC.