Nkhaniyi ikufotokoza momwe kamangidwe kake kakang'ono ka Teflon yopumira (PTFE) yotentha kwambiri imasinthira kutulutsa kwa mpweya ndi kutchinjiriza komanso zinthu zopanda ndodo. Mkangano wapakati: Kutha kwa mpweya kumafuna ma pores otseguka, pomwe kutchinjiriza kumafuna kachulukidwe komanso kusamata kumafuna malo osalala. Zolinga zopangira njira: kuwongolera m'mimba mwake (0.1-2μm, bwino <0.5μm) kuti muteteze kusungunula ndikusunga magetsi owonongeka; kuwongolera porosity pa 50-70% (≈60% mulingo woyenera) kukwaniritsa Gurley 20-100s/100cc ndi mphamvu ya dielectric ≥2kV kwa filimu ya 0.13mm; kutengera mawonekedwe apamwamba a 3D network pore (τ≈2.5-4) kupondereza njira zowongoka; kumanga asymmetric gradient pore kapangidwe ndi wandiweyani pamwamba wosanjikiza khungu (1-5μm) kwa sanali ndodo/kutsekereza ndi porous mkati kuti mpweya; gwiritsani ntchito super-oleophobic/hydrophobic surface post-treatment popanda pore blockage.

Nkhaniyi ikupereka ubwino PTFE mkulu-kutentha nsalu monga mkulu-kutentha fyuluta TV. Mphamvu zisanu ndi chimodzi zazikulu: Kukana kutentha kwapadera (260 ° C mosalekeza, nsonga ~ 300 ° C), kupitirira PPS (190 ° C) ndi aramid (200 ° C); Kusagwira bwino kwa mankhwala motsutsana ndi zidulo, ma alkali, zosungunulira ndi ma okosijeni, zosagonjetsedwa ndi hydrolysis, aramid yopambana ndi P84 mu mpweya wowononga wa flue; Kuchita bwino kwambiri koyeretsa fumbi ndi mphamvu yotsika kwambiri yomwe imathandizira kuchotsa keke yafumbi komanso kutsika kwapang'onopang'ono; Kuchita bwino kwambiri kusefera ndi kukula kwa pore 0.1-3μm kumagwira 99.99% ya tinthu tating'ono ta PM2.5; Kusatentha ndi LOI pamwamba pa 95%, ndi zosankha zotsutsana ndi static zomwe zilipo; Mphamvu zamakina apamwamba kuchokera ku kulimbikitsa magalasi a fiberglass, okhala ndi PTFE fiber media yoyera yopereka kusinthasintha ndi> moyo wautumiki wazaka 4. Yerekezerani bwino ndi PPS, aramid, Nomex, P84 ndi fiberglass zosefera pa kutentha, kukana mankhwala, kukana kwa hydrolysis ndi ntchito yoyeretsa.

Nkhaniyi imapereka njira zothetsera zotsalira zotsalira ndi zomatira kukhetsa magazi mukamagwiritsa ntchito tepi yotentha kwambiri ya PTFE kuteteza zala zagolide za PCB panthawi ya msonkhano wa SMT. Kusanthula kwazomwe zimayambitsa: zotsalira zimachitika chifukwa cholephera kugwirizanitsa kapena kusamutsa kwapakati; kukhetsa magazi kumachitika chifukwa cha kukhuthala kwa madontho ndi zomatira kusefukira pansi pa kutenthanso. Yankho lapakati ndiloyenera kusankha tepi: silikoni PSA yokhala ndi nsonga yaifupi ≥300 ° C, mosalekeza ≥260 ° C, makulidwe okwana 0.08-0.13mm okhala ndi zigawo zoonda kwambiri zomatira, ndi chiphaso chotsutsa magazi / chotsalira. Kuwongolera njira zisanu ndi chimodzi: kuyeretsa kusanachitike ndi IPA; zero-tension lamination ndi kutulutsa mpweya wonse; wokometsedwa reflow kutentha mbiri ndi kutentha pang'ono (<2°C/s); kuzizira kozizira pansi pa 50 ° C pa ngodya ya 180 °; kukonza mwachangu mkati mwa maola 24 ndikugwiritsa ntchito kamodzi kokha; Kulephera kugwira ntchito ndi IPA kupukuta ndi kuwunika kwa 40-50x magnifier. Kwa ma PCB a mbali ziwiri, sinthani ndi tepi yatsopano musanakonzenso mbali yachiwiri.

Nkhaniyi amapereka malangizo mwadongosolo kupewa makwinya pa PTFE mkulu kutentha nsalu pa sintering. Makwinya amayamba chifukwa cha kuchepa kwamafuta osagwirizana komanso kupsinjika kosagwirizana. Mayankho amaphimba mayendedwe athunthu: zopangira gawo lapansi kuwongolera (kutsitsa kwathunthu / kuyika kutentha kuti muchepetse kupsinjika kwamkati); kuyanika ndi kuyanika (zopaka zingapo zopyapyala, kutentha pang'ono, zodzigudubuza zoyendetsa); kuwongolera ng'anjo ya sintering (1-3% overfeed for thermal shrinkage allowance, shut-loop micro-tension control, transverse kutentha kutentha mkati mwa ± 5°C, gradient preheating-sintering-cooling curve, ng'anjo zoyandama mpweya monga njira yoyenera, zodzigudubuza zopindika); kuziziritsa ndi kuyika (kuzizira pang'onopang'ono, sungani kufalikira mpaka pansi pa 100 ° C, kuzizirira kwathunthu kusanapirire); kuwunika kwapaintaneti ndikuwunika mwamphamvu komanso kuwunika kwa infrared.

Nkhaniyi ikuwunika momwe sandblasting kapena matt kumaliza chithandizo kumakhudzira mawonekedwe a pamwamba pa nsalu ya PTFE yotentha kwambiri. Zosintha zimachitika m'magawo atatu: Microscopic morphology imasintha kuchoka pagalasi losalala mpaka mawonekedwe owoneka bwino okhala ndi ma Ra/Rz okwera kwambiri, ndikupanga zomangira za 3D zomangirira. Kupaka umphumphu kumakumana ndi zoopsa: PTFE kupatulira kosanjikiza, kuwonekera kwa fiberglass gawo lapansi (kuyambitsa kutayika kwa katundu wopanda ndodo, kulowa kwa chinyezi, ndi kuchepa mphamvu zamakina), kuphatikiza ma microcracks ndi zinyalala.

Nkhaniyi ikufotokoza njira zonse zofunika zopangira nsalu za fiberglass ndi PTFE emulsion. Masitepe asanu ndi awiri ofunika: ① Pretreatment (dewaxing/desizing) pa 350-400°C kuchotsa zinthu zoyezera nsalu; ② Mapangidwe a emulsion okhala ndi 40-55% olimba komanso zowonjezera zowonjezera pakunyowetsa bwino; ③ Kulowetsedwa kudzera mu njira yofinya kapena zokutira tsamba la dokotala; ④ Kuyanika pa 100-150 ° C kuti musungunuke madzi pang'onopang'ono ndikupanga filimu yowuma ya PTFE; ⑤ Sintering pa 360-390 ° C (mpaka 400 ° C) kusungunula particles PTFE mu filimu mosalekeza; ⑥ Mipikisano mkombero impregnation-kuyanika-sintering mobwerezabwereza 2-4 nthawi kukwaniritsa chandamale makulidwe ndi utomoni okhutira (45-65%); ⑦ Kuchiza pambuyo pochiza kuphatikizirapo kuchiza kwa corona, kudula m'mphepete, kutsekereza ndi kuyang'ana bwino. Kore ulamuliro mfundo: dewaxing wathunthu, zonse emulsion wetting, pang'onopang'ono kuyanika, yeniyeni sintering kutentha, ndi kusasinthasintha ❖ kuyanika kachulukidwe. Zogulitsa zimagwiritsa ntchito ma laminates okhala ndi mkuwa wokwera kwambiri, malamba onyamula kutentha kwambiri komanso zida zomanga.

Nkhaniyi ikukhudzana ndi zizindikiro zazikulu za PTFE tepi yotentha kwambiri yomwe imagwiritsidwa ntchito popaka vacuum, chithandizo cha kutentha kwa vacuum ndi malo ofanana. Zofunikira zazikulu zimasiyana kwambiri ndi kugwiritsa ntchito mlengalenga: kutulutsa mpweya ndikovuta kwambiri (TML≤1%, CVCM≤0.1%; magalasi owulutsa ndege / kuwala amafuna TML≤0.5%, CVCM≤0.01%); kukana kutentha kuyenera kutsimikiziridwa pa gawo lapansi la PTFE (260 ° C) ndi wosanjikiza zomatira; Siloxane PSA yoyeretsedwa mwapadera imafunikira kuti mupewe kuipitsidwa kwa siloxane; Kutentha kwakukulu kumalepheretsa kukwawa ndi kukweza m'mphepete; ukhondo sumafuna kukhetsa kwa ulusi komanso kutsika kwa ayoni; tepi yotsutsa-static (resistivity pamwamba 10⁶-10⁹ Ω/sq) imalepheretsa kuwonongeka kwa ESD; kukana kwa plasma kuyenera kuwunikidwa panjira za sputtering/PECVD; Kutsika kwamafuta pansi pa 2% kumatsimikizira kubisala bwino.

Nkhaniyi ikuwonetsa zosungunulira za organic zomwe nsalu ya PTFE yotentha kwambiri imatha kupirira. Nsalu ya PTFE-yakutidwa ndi fiberglass imawonetsa kusakhazikika kwapadera kwamankhwala, kukana pafupifupi zosungunulira zonse wamba pansi pamikhalidwe yabwinobwino yogwirira ntchito popanda kusungunuka, kutupa kapena kuchitapo kanthu. Magulu olekerera akuphatikizapo: mowa (methanol, ethanol, isopropanol), ketoni (acetone, MEK, cyclohexanone), esters (ethyl acetate, butyl acetate), ma hydrocarbons (petulo, toluene, xylene, hexane), halogenated hydrocarbons (dichloromethylene), carbon dioxide, ether THF), ma organic acid (glacial acetic acid, formic acid), amines ndi amides (triethylamine, DMF), phenols, ndi ena monga carbon disulfide, pyridine, silikoni mafuta ndi brake fluid.

Nkhaniyi ikukhudza kuzirala zofunika pa PTFE mkulu-kutentha nsalu sintering. Pambuyo pa sintering pa 380-400 ° C, nsaluyo iyenera kudutsa mofulumira kudera la 310-315 ° C crystallization-sensitive zone. Kuzizira kovomerezeka ndi osachepera 30-50 ° C/mphindi (nsalu yopyapyala imatha kufikira 100-200 ° C/mphindi kudzera kuzizira kwa mpweya). Kuzizira kofulumira (kuzimitsa) kumatulutsa kuwala kocheperako (45-50%), kumapereka zokutira zofewa, zolimba zokhala ndi malo osalala, zomatira zolimba, kuchita bwino kosagwira ndodo, komanso kukana delamination ndi kusweka. Kuziziritsa pang'onopang'ono (kuzizira kwa ng'anjo) kumabweretsa kuwala kwakukulu (60-70%), kumapangitsa kuti zokutira zolimba, zowonongeka zomwe zimachepa, kusenda ndi microcracks.

Nkhaniyi ikufananiza kutentha kwa chipinda ndi kutentha kwapamwamba kwa zomatira za PTFE za PTFE. Kutentha kwapamwamba (120-180 ° C) kumapanga maukonde ophatikizika okhala ndi mphamvu zolumikizana mwamphamvu, kuteteza zotsalira zomatira pambuyo pakusenda. Amapanga ma anchoring bond okhala ndi magawo a PTFE kudzera pa primer co-curing, kuchotsa ziwopsezo za delamination. Kutentha kwapamwamba kumachotsanso kusungunuka kwa mamolekyu musanayambe kubereka, kuteteza kuphulika ndi kuipitsidwa kwa mafuta a silicone pakuwotcha koyamba.