Polyethyleneqeb ntawm cov khoom siv thermoplastics thoob plaws ntiaj teb, nrog rau txhua xyoo ntau tshaj 100 lab metric tons. Qhov no saturated hydrocarbon polymer, feem ntau yog los ntawm ethylene monomer los ntawm catalytic polymerization, nthuav tawm cov qauv molecular yam ntxwv los ntawm kev rov ua dua -CH₂- units. Cov khoom siv ntau yam yog los ntawm nws qhov sib txawv ntawm qhov sib txawv, qhov feem pua ntawm crystallinity, thiab qhov hnyav molecular faib tawm - cov kev ntsuas uas tsim los txiav txim siab cov khoom siv hluav taws xob, kev coj tus cwj pwm thermal, thiab xaus - siv qhov tsim nyog thoob plaws hauv kev lag luam.
Dab tsi ua rau PE txawv ntawm lwm cov yas
Nov yog qee yam uas ua rau tib neeg mus tas li: polyethylene tsis yog ib qho khoom siv. Nws yog ib tsev neeg tag nrho.
Lub caj qaum chemistry nyob twj ywm tib yam, tseeb. Tab sis lub branching? Qhov ntawd hloov txhua yam. HDPE muaj cov ceg me me-tej zaum 5-10 ceg luv luv ntawm 1,000 carbon atoms. Cov chains ntim nruj nreem. ntom. Muaj zog. LDPE? Tsi txawv kiag li. Ntev-txoj saws nyob txhua qhov chaw, qee zaum 20-30 ceg ntawm 1,000 carbons. Cov qauv nyob twj ywm xoob, hloov tau.
Kuv tau pom engineers qhia "PE" ntawm cov duab kos yam tsis nkag siab qhov sib txawv no. Lub hlis tom qab, lawv cov khoom ua tsis tiav. Hom tsis ncaj ncees lawm.
Qhov ceev qhia zaj dab neeg:
LDPE: 0.910-0.940 g / cm³
HDPE: 0.941-0.965 g / cm³
Tsis zoo li ntau. Yim feem pua sib txawv, kwv yees li. Tab sis qhov sib txawv ntawd txiav txim siab seb koj cov khoom puas muaj sia nyob ntawm cov nroj tsuag tshuaj los yog raug crushed nyob rau hauv nruab nrab load.
HDPE: Cov neeg ua haujlwm tsis muaj leej twg hais txog
HDPE yeeb nkab rau kev teeb tsa dej yuav yog daim ntawv thov tho txawv tshaj plaws. Kuj tseem ceeb tshaj plaws.
Cov dej hauv nroog thoob ntiaj teb vam khom rau PE100 yeeb nkab- uas yog HDPE ntsib cov kev ntsuas tshwj xeeb (MRS Ntau dua lossis sib npaug li 10.0 MPa). Cov tshuaj tiv thaiv ntawm polyethylene txhais tau tias cov kav dej no tuav cov dej chlorinated rau ntau xyoo tsis muaj degradation. Tsis muaj corrosion. Tsis muaj tuberculation zoo li koj xav pom hauv cov kav hlau.
HDPE qhov ntsuas kub siab tshaj 80℃rau kev pabcuam txuas ntxiv. Tsis zoo siab piv rau engineering thermoplastics. Tab sis rau cov yeeb nkab faus? Zoo meej. Hauv av kub tsis tshua muaj siab tshaj 25℃txawm li cas los xij.
Tensile lub zog PE hauv HDPE ntau yam hits 20-37 MPa nyob ntawm qib tshwj xeeb. Txais tau rau cov qauv siv thaum koj tsim tsim nyog. Cia li tsis txhob cia siab rau tej txuj ci tseem ceeb.
Dab tsi tiag tiag impresses kuv txog HDPE yog polyethylene tshuaj tiv thaiv profile. Concentrated sulfuric acid? Zoo. Sodium hydroxide yog dab tsi? Tsis muaj teeb meem. Feem ntau cov organic solvents hauv qab 60 degree? tuav lawv. Cov oxidizers muaj zog yuav tawm tsam nws thaum kawg, thiab cov pa roj carbon monoxide uas muaj ntxhiab ua rau o, tab sis tag nrho cov kev tiv thaiv ua tau zoo tshaj ntau cov ntaub ntawv uas raug nqi tsib zaug ntau dua.
LDPE thiab Yog vim li cas Flexibility tseem ceeb dua li koj xav
Ntim zaj duab xis PE dominates lub lag luam LDPE. Cov hnab yas PE no txhua leej txhua tus yws txog? LDPE lossis LLDPE, feem ntau.
Cov khoom siv kho tshuab PE nthuav tawm nyob rau hauv qis- cov qib ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom. Peb tab tom tham 100-650% elongation thaum so. Zaj duab xis stretches, conforms, recovers. Sim ua li ntawd nrog HDPE-nws yuav caj dab thiab poob.
Cov khoom cua sov ntawm polyethylene hauv LDPE ntau yam qhia qis crystallinity (40-55% piv rau 65-80% rau HDPE). Tsawg melting point thiab. PE melting point rau LDPE zaum ntawm 105-115 degree; HDPE khiav 130-137 degree.
Rau PE zaj duab xis ntim cov chaw tsim khoom lag luam, qhov kev ua haujlwm no tseem ceeb heev. Qhov kub qis dua txhais tau tias muaj zog tsawg. Lub voj voog nrawm dua. Thinner gauges ua tau yam tsis muaj tearing thaum extrusion ntawm PE.
Kev sib piv PE vs PP Txhua tus tau yuam kev
Kuv yuav tsum tau hais txog qhov no vim qhov tsis meej pem tsis tas yuav xaus.
Polyethylene vs polypropylene-lawv yog ob qho tib si polyolefins. Ob leeg hydrocarbons. Ob leeg zoo ib yam li pellets. Tab sis qhov sib txawv ntawm PE thiab PP tshwm sim tam sim hauv daim ntawv thov.
PE qhov zoo:
Kev cuam tshuam zoo dua ntawm qhov kub thiab txias
Superior tshuaj compatibility PE rau acids/bases
Tus nqi qis dua feem ntau
Zoo dua kev ntxhov siab tawg kuj
PP qhov zoo:
Muaj peev xwm kub siab (kev pabcuam rau 100℃+)
Kev qaug zog zoo dua rau cov hinges nyob
Lower density (lub teeb qhov chaw)
Siab saum npoo hardness
Tus nqi PE vs PP hloov pauv nrog cov nqi khoom noj. Qee zaum yuav luag zoo ib yam. Qee zaum 15-20% sib kis. Raw khoom PE tus nqi ib kg khiav qhov twg los ntawm $1.00 txog $2.50 nyob ntawm qib, cheeb tsam, thiab kev ua lag luam. Cov qib tshwj xeeb- qib zaub mov PE daim ntawv xa khoom tus nqi, piv txwv li-hais kom them nqi.
Polyethylene tus nqi tag nrho tseem nyob ntawm qis tshaj rau txhua yam thermoplastic. Qhov ntawd yog qee qhov vim li cas cov khoom ntim khoom nyob siab heev.
Khoom noj khoom haus kev nyab xeeb thiab ua raws (Dab tsi cov kev cai hais tiag)
Puas yog polyethylene muaj kev nyab xeeb rau kev sib cuag zaub mov?
Cov lus teb luv luv: feem ntau yog, thaum tsim kom raug.
FDA pom zoo PE qib muaj nyob tshwj xeeb rau daim ntawv thov kev sib cuag zaub mov. Cov kev cai (21 CFR 177.1520) qhia txog cov khoom siv ntxiv, kev pab cuam, thiab xaus - siv cov xwm txheej. Khoom noj khoom haus qib polyethylene yuav tsum ua kom tau raws li cov kev txwv kev tsiv teb tsaws chaw- cov khoom tsis tuaj yeem nkag mus rau hauv cov zaub mov saum toj kawg nkaus uas tau teev tseg.
BPA- pub dawb PE yog qee yam lus tsis txaus ntseeg. Polyethylene yeej tsis muaj BPA. Qhov ntawd yog qhov teeb meem polycarbonate / epoxy. Cov tuam tsev lag luam nyiam qhov kev thov lawm.
Khoom noj khoom haus-Kev nyab xeeb yas PE daim ntawv pov thawj sib txawv raws li txoj cai:
- FDA (USA)
- EU 10/2011 (Tebchaws Europe)
- GB 4806 series (Tuam Tshoj)
RoHS PE ua raws li qhov tseem ceeb rau cov ntawv thov hluav taws xob, tsis yog kev sib cuag zaub mov. Cov kev cai sib txawv kiag li. Daim ntawv pov thawj polyethylene toj roob hauv pes tau hloov pauv sai vim tias cov kev xav tau sib tshooj tab sis tsis ua kom zoo.
Rau cov zaub mov qib PE daim ntawv xa khoom xaiv, thov cov ntaub ntawv cov ntaub ntawv uas qhia txog kev pom zoo. Tsis txhob xav tias. Kuv tau pom "qib zaub mov" thov ntawm cov ntaub ntawv uas dhau los tsis muaj kev ntsuam xyuas cuam tshuam dab tsi.
Manufacturing Methods: Quick Rundown
Extrusion
Extrusiontuav zaj duab xis, ntawv, yeeb nkab, profiles. Cov txheej txheem txuas ntxiv. PE daim ntawv ntau lawm, PE zaj duab xis manufacturing-txhua yam kev hloov pauv.
01
Txhaj tshuaj molding PE
Txhaj tshuaj molding PEtsim cov khoom sib cais. Caps, kaw, ntim, cov khoom lag luam. Lub sij hawm voj voog nyob ntawm qhov tuab ntawm phab ntsa. Nyias- ntim cov phab ntsa khiav 3-5 thib ob. Kev lag luam hnyav yuav xav tau 60+ vib nas this.
02
Tshuab molding
Tshuab moldingtsim hollow qhov chaw. Lub raj mis feem ntau. HDPE mis nyuj jugs yog cov piv txwv canonical.
03
Kev sib hloov molding
Kev sib hloov moldingua rau qhov loj hollow- tanks, kayaks, khoom ua si. LDPE zaj duab xis yob cov neeg muag khoom lag luam qee zaum muag cov khoom siv hauv av tshwj xeeb rau cov ntawv thov rotomolding, txawm tias LLDPE thiab HDPE pom siv ntau dua.
04
PE resin rau kev txhaj tshuaj molding yuav tsum tau ua tib zoo saib xyuas cov dej ntws. Tsawg dhau, koj tsis tuaj yeem sau cov pwm. Siab dhau lawm, teeb meem flash thiab dimensional. Cov qib txhaj tshuaj ib txwm khiav 2-30 g / 10min ntawm 190℃/ 2.16kg.
Recycling Reality Check
Polyethylene puas tuaj yeem siv tau? Technically, kiag li.
Polyethylene recycling cim qhia #2 rau HDPE, #4 rau LDPE. Feem ntau cov kev pab cuam hauv nroog lees txais #2 nkag. #4 qhov kev lees txais sib txawv wildly raws qhov chaw.
Cov nqi siv rov ua dua tshiab? Kev poob siab. Cov teeb meem kev kis kab mob, kev xa khoom thauj, kev lag luam nyiaj txiag -tej zaum 30% ntawm HDPE fwj yeej tau rov siv dua hauv kev xyaum. Cov yeeb yaj kiab tsis zoo. Ib tus lej - feem pua feem pua.
Mechanical recycling degrades cov khoom. Txhua qhov keeb kwm ntawm tshav kub txo qhov hnyav molecular me ntsis. Kev siv PE feem ntau nkag mus rau hauv qis dua - daim ntawv thov muaj nqis dua li cov khoom siv nkauj xwb. Downcycling, qhov tseem ceeb.
Cov cuab yeej siv tshuaj lom neeg rov ua dua tshiab-pyrolysis, solvolysis- cog lus tias yuav tau txais txiaj ntsig zoo dua. Kev lag luam nplai tseem txwv raws li xyoo tas los no. Kev lag luam tseem tsis tau ua haujlwm rau feem ntau cov khoom noj.
Technical Data Snapshot
Rau cov neeg xav tau cov lej, ntawm no yog cov ntaub ntawv polyethylene cov ntaub ntawv nkag feem ntau qhia:
| Khoom | LDPE | HDPE |
|---|---|---|
| Qhov ceev (g / cm³) | 0.910-0.940 | 0.941-0.965 |
| Tensile zog (MPa) | 8-25 | 20-37 |
| Elongation (%) | 100-650 | 10-1200 |
| Melting Point (zeeg) | 105-115 | 130-137 |
| Kev pab Temp Max (degree) | 60-75 | 80-100 |
| Ntug D Hardness | 41-50 | 60-70 |
Polyethylene cov khoom specifications sib txawv heev los ntawm cov qib pes tsawg. Cov kab no suav nrog cov khoom siv. Tshwj xeeb copolymers, qib bimodal, thiab crosslinked variants poob sab nraum cov ciam teb no.
PE density ib leeg tsis kwv yees kev ua tau zoo-koj xav tau cov khoom siv polyethylene tag nrho nrog rau cov khoom hnyav molecular, cov ntsiab lus comonomer, thiab cov ntsiab lus ntxiv pob.
Kev xav zaum kawg
Polyethylene yuav tsis yeej khoom plig rau siab - daim ntawv thov kev ua tau zoo. Cov kev txwv kub tsis suav nrog hauv qab - hood automotive Cheebtsam. Lub modulus yog tsawg dhau rau cov khoom siv engineering. Creep ua qhov tseem ceeb nyob rau hauv kev txhawb nqa loads.
Tab sis rau cov tshuaj tso tsheb hlau luam, cov yeeb nkab dej, ntim cov yeeb yaj kiab, cov khoom siv? Cov hom polyethylene muaj niaj hnub no suav nrog ntau yam kev xav tau ntawm cov khoom muag.
Kev siv cov khoom siv PE txuas ntxiv mus ntxiv vim cov neeg tsim khoom tsim kho tshiab. Kev khi siab dua- txheej adhesion. Zoo dua UV stabilization. Txhim kho cov yam ntxwv ua haujlwm. Lub hauv paus polymer nyob twj ywm tib yam; txhua yam nyob ib puag ncig nws txhim kho.
HDPE cov khoom siv nqi ib kg ua rau nws siv tau rau cov ntawv thov uas tsis tuaj yeem ua pov thawj cov khoom yas yas. LDPE zaj duab xis yob cov nqi lag luam wholesale ua rau lub ntim ntim tau yooj yim ntawm qhov ntsuas uas lwm qhov tsis tuaj yeem ua rau kev lag luam.
Qee lub sij hawm cov khoom siv feem ntau yog siv rau qhov laj thawj zoo.
Yog xav paub ntxiv txog kev yuav khoom lossis cov khoom siv polyethylene, thov sab laj nrog peb. Peb tuaj yeem muab cov ntaub ntawv qhia kev thiab cov ntaub ntawv ua raws cai rau cov qib tshwj xeeb.