Dab tsi yog Kev Lag Luam - Tawm Ntawm Kev Siv Tsawg- Melt-Flow-Index (MFI 2) PFA Resin vs. Standard (MFI 8) Resin rau Extruding 1.5 mm Phab Ntsa Tubes rau Siab -Kev Pab Cuam Siab ntawm 180 degree?
Tso lus
Ib qho qis-melt-flow- Performance index PFA resin (MFI 2) muab ntau dua creep tsis kam thiab lub neej ntev dua li ib txwm MFI 8 resin rau siab -siab qhov kev pab cuam ntawm 180℃, tab sis ntawm tus nqi ntawm cov tshuaj tsis muaj zog me ntsis thiab kev tsim khoom nyuaj. Qhov hnyav molecular ntawm qis-MFI resin (kwv yees li 400 kDa as opposed to 200–250 kDa) txhim kho cov neeg kho tshuab lub zog thiab txo qis hauv qab siab. Lub tshuab hluav taws xob MFI 2 siv sijhawm ntev dua 10,000 teev ua ntej nkag mus rau qhov 1.5 hli phab ntsa raj ntawm 180℃thiab 10 bar sab hauv siab, qhov MFI 8 lub rhaub dej tsis ua haujlwm li ntawm 2,000-4,000 teev. Kev lag luam tawm -tawm yog qhov qis-MFI resin xav tau qeeb extrusion ceev thiab siab dua extrusion kub (400–420℃vs{29}}–390℃), uas nce nqi tsim khoom los ntawm 20–40%. Tsawg-MFI PFA tau pom zoo rau chav dej siab tshaj 160℃. Standard MFI 8 yog txaus rau cov uas tsis yog - cov ntawv thov siab los yog qis dua (<140°C).
Kev sib piv ntawm creep kuj ntawm 180℃thiab 10 bar hoop stress (1.5 hli phab ntsa, 25 hli OD)
PFA Qib MFI (g / 10 min) Lub Sijhawm Rau Kev Ruaj Ntseg (teev) Lub Sijhawm rau 1% Creep Strain (teev) Molecular Luj (kDa) Hom Kev Ua Tsis Zoo
Siab heev MW 0.5–{1}},000–8,000 15,000–25,000 brittle breakage
Tsawg MW (kev ua haujlwm siab) 2–3 350–450 3,000–5,000 8,000–15,000Rupture ntawm creep
Standard (tag nrho-lub hom phiaj) 5–8 200–250 500–1,500 2,000–4,000Rupture ntawm creep
Siab ntws (yooj yim extrusion) 10–15 150–180 200–500 800–1,500 nrawm nrawm
Reprocessed/recycled 15+<150 <200 <500Failure right away
Qhov laj thawj qis-MFI Resin ua haujlwm zoo dua ntawm qhov kub thiab txias
PFA yuav luag ntawm nws qhov softening point ntawm 180℃(melting pib ntawm 305 degree, txawm hais tias modulus drastic txo qis dua 150 degree). Ntau entanglements nyob rau hauv siab molecular hnyav chains tiv thaiv saw slippage, los yog creep. Kev nrawm nrawm thiab tawg tau tshwm sim los ntawm cov saw luv luv (tsis tshua muaj molecular hnyav) zawv zawg ib leeg yooj yim dua. Lub neej ∝ 1 / (MFI)^1.5 yog kwv yees li kev sib txuas ntawm MFI thiab lub neej nkag mus. MFI 2 resin muaj 8 × MFI ntawm MFI 2. Tuav, MFI 8 rau MFI 2=4. 4^1.5=8 yog lub neej piv. Raws li cov ntaub ntawv, MFI 2 yuav tsum kav 8 × ntev dua (10,000 vs . 2,000 teev=5 × qhov sib txawv, nyob rau hauv tawg).
Tsawg-MFI Resin Processing nyuaj
Kev cuam tshuam ntawm Parameter Standard MFI 8 Tsawg MFI 2
Kub ntawm extrusion: 370-390 degree; 400-420℃Kev siv hluav taws xob ntau ntxiv
Slower, tsawg dua throughput Extrusion ceev (m/min) 5–10 2-4
Qhov nruab nrab tuag siab 30-50% siab dua yuav tsum muaj cov cuab yeej muaj zog dua.
Smooth nto zoo tejzaum nws rougher (melt puas).Nws yuav tsum tau polishing.
Tus nqi (kev ua haujlwm + resin) Lub hauv paus + 20–40% Tus nqi nce ntxiv
Piv txwv hauv Teb
Standard MFI 8 resin 1.5 mm wall PFA heaters were used in a steam steriliser (180°C, 8 bar). After 1.5–2 years (about 3,500–5,000 hours), heaters failed. The same manufacturer's low-MFI resin (MFI 2.5) was adopted by the factory. Extrusion cost 25% more and was slower (3 m/min vs. 7 m/min). The new heaters had a lifespan of more than six years (>12,000 teev). Kev txo qis qis tau tso cai rau lub Hoobkas rov qab tau tus nqi pib siab dua hauv tsawg dua ob xyoos. Rau txhua qhov kev pabcuam chav dej siab tshaj 150 degree, tam sim no lawv xav tau MFI Tsawg dua lossis sib npaug li 3.
Thaum MFI 8 Standard Tau Txais
Lub creep tus nqi qis dua thaum qhov kub ntawm qhov kub tsawg dua 150 degree.
Hoop nro yog tsawg heev nyob rau hauv qis siab (3 bar).
Kev pabcuam cuam tshuam (tsis tas mus li): Thaum lub sijhawm tawm - mus, cov polymer kho tau zoo.
Phab ntsa tuab (Ntau dua lossis sib npaug li 2.5 hli): Molecular hnyav tseem txwv cov khoom uas tuaj yeem nkag mus.
Ua lag luam-Tawm rau tshuaj tiv thaiv
Qhov me ntsis ntxiv crystallinity ntawm qis-MFI resin (55–60% vs. 45-50% rau tus qauv) txo qis permeability tab sis tej zaum yuav txo qis kev cuam tshuam. Cov tshuaj tiv thaiv tau txais txiaj ntsig los ntawm kev nce crystallinity (qis amorphous dawb ntim). Txawm li cas los xij, yog tias qhov extrusion faults (melt fracture) tsis tswj, pinholes yuav tshwm sim. Qhov qis-MFI resin tsis qis dua rau cov tshuaj lom neeg; Qhov tseeb, vim nws cov crystallinity nce ntxiv, nws yuav zoo dua me ntsis.
Xaus: Tsawg-MFI (2–3) Extens Life 3–5 × Tshaj Standard MFI 8 rau 180℃Chav
PFA rhaub ua los ntawm qis-melt-flow-index resin (MFI 2–3) muaj 3-5 × lub neej ntev dua li ib txwm MFI 8 resin rau siab -siab zog lub luag haujlwm ntawm 180℃vim nws qhov hnyav dua molecular thiab zoo dua creep resistance. Cov zis qis dua thiab cov nqi tsim khoom ntau dua (20–40%) yog kev lag luam tawm - tawm. Cov nqi them nqi yog lav rau kev siv lub sijhawm ntev dua li 160 degree. Standard MFI 8 yog tsim nyog rau cov uas tsis yog{18}} cov ntawv thov siab lossis qis dua. Creep lub neej ntawm qhov kub thiab txias yog txiav txim siab los ntawm qhov hnyav molecular, uas yog qhia los ntawm cov dej ntws ntsuas. Lub neej ntev yog txuam nrog qis MFI. Lub neej luv luv yog qhia los ntawm MFI siab. Ua qhov kev txiav txim zoo. Mus qis hauv chav. Koj lub tshuab cua sov yog ntev - kav ntev. Cov nuj nqis ntxiv ua ntej yuav zoo dua los ntawm kev txuag nyiaj poob haujlwm. Kev lag luam- tawm yog qhov ntawd. Kev txawj ntse peev.
