Yaushe PTFE m tef da ake amfani da su hatimi danshi-m aka gyara - kamar lantarki enclosures, HVAC flanges, ko sinadaran ganga murfi - na kowa zato shi ne cewa PTFE ta hydrophobicity yana ba da garantin cikakken ruwa tururi shãmaki. Wannan ba koyaushe gaskiya bane.
Kwayoyin tururin ruwa kanana ne. Za su iya yaduwa ta hanyoyin da ba a iya gani ba, wanda ruwa mai yawa ba zai iya ba. Ainihin ruwa tururi watsa kudi (WVTR) na PTFE tef dogara kasa a kan PTFE ta sunadarai da kuma more a shafi tsarin – lahani kamar micropores, microcracks, kuma bai cika fiber encapsulation.
Aokai PTFE ya bincika WVTR a fadin kayan shafa da kauri. Wannan labarin yana bayanin yadda tsarin sinadarai na PTFE, lahani na sutura, dabarun kauri, da gyare-gyaren filler suna haɗuwa don ƙayyade aikin shingen tururi.
Tsarin Sinadarai na PTFE - Dukansu Fa'idodi da iyakancewa
1. Abũbuwan amfãni - Hydrophobicity da Crystallinity
Siffar
Amfanin Ruwan Ruwan Ruwa
CF shaidu, ƙarancin makamashi mai ƙarfi
Kwayoyin ruwa da kyar suke toshewa ko narke akan saman PTFE - shinge na farko akan shigar danshi
Babban crystallinity (> 90%)
Yankunan lu'ulu'u suna kusa da ba za su iya shiga tururi ba - babu hanyar yaduwar kwayoyin halitta ta hanyar lu'ulu'u
2. Iyakance - Yankunan Amorphous da Ƙwararrun Ƙwararrun Ƙwararru
Ƙarfin intermolecular mai rauni tsakanin sarƙoƙin ƙwayoyin cuta na PTFE
Ƙwaƙwalwar ƙarar ƙarar kyauta a cikin yankunan amorphous suna haifar da hanyoyin yadawa
Fim ɗin PTFE mai tsafta yana ba da WVTR matsakaici kawai - ƙasa da PVDC ko EVOH
PTFE ba ingantaccen kayan shinge ba ne
Maɓalli mai mahimmanci: PTFE na ciki shine shinge mai matsakaici, ba na musamman ba. Ayyukan tef ɗin da ya dace ya dogara da lahani sosai.
Matsalolin Rufe Mahimmanci - Micropores, Microcracks, da Fiber Wicking
Wannan shi ne babban abin da ke tafiyar da aikin shinge mai amfani. Yawancin kaset na PTFE ana kera su ta hanyar impregnation ko shafi na tarwatsawar PTFE da sintering, yayin da ake haifar da lahani masu mahimmanci:
Nau'in Lalacewa
Ƙirƙirar Tsarin Mulki
Tasiri akan WVTR
Micropores
Abubuwan kaushi masu ƙarfi da ƙarancin guduro Fusion sun bar ɓoyayyen haɗin gwiwa
Ƙirƙirar gajerun hanyoyi don shigar tururi
Microcracks
Rashin daidaituwar haɓakar thermal tsakanin fiberglass substrate da PTFE yana haifar da fashe mai kyau bayan sintering / sanyaya
Yana buɗe tashoshi kai tsaye ta hanyar sutura
Capillary wicking na fibers
Rashin cikar cikar filayen gilashin yana ba da damar tururin ruwa don ratsawa tare da haɗin fiber-resin interface ta hanyar aikin capillary
Yana ba da damar kewayawar tururi a kusa da rufin
Ƙarshe mai fa'ida: Gabaɗaya WVTR na tef ɗin PTFE da aka gama ana sarrafa shi da ƙarancin lahani , ba ainihin kayan aikin babban resin PTFE ba.
Aokai PTFE yana ba da kaset ɗin mannewa na PTFE tare da yawan suturar sarrafawa. Don aikace-aikacen da ke buƙatar ƙananan WVTR (<15 g/m² · rana), muna ba da shawarar ƙimar mu mai rufi mai yawa, wanda ke amfani da wucewar impregnation guda uku don ci gaba da rufe ramuka da rage ƙarancin microcrack.
Rufe Kauri da Tasirin Labyrinth - Dabaru don Rage WVTR
Ƙara kauri yana ƙara hanyar shiga tururi amma da kyar ya rufe lahani na tsarin da ake da shi kaɗai. An jera hanyoyin inganta ingantaccen inganci a ƙasa:
Dabarun
Makanikai
Tasiri
Multi-Layer shafi
Maimaita impregnation da sintering suna ba da damar yadudduka masu zuwa don rufe ramuka da kuma lalata wuraren lahani na riguna.
Tsanaki tare da masu cikawa: Yin ɗimbin filaye da yawa zai lalata sassauƙa da kaddarorin da ba na sanda ba na samfuran da aka gama. Ana buƙatar ma'auni.
Yanayin Sama - Hydrophobic amma Ba Mai Hukunci ba
A hydrophobic PTFE shafi yana da wani babban ruwa lamba kwana (yawanci 110-120 °), hana ci gaba da ruwa film samuwar a kan surface da kuma kai tsaye saukar da tururi shigar da karfi tuki.
Duk da haka: Wannan fa'idar saman ba zai iya kashe shinge mara kyau wanda lahani na ciki ya haifar ba. Idan micropores ko fasa sun wanzu, tururin ruwa zai har yanzu yaduwa ta hanyar ko da kuwa yanayin hydrophobicity.
Takaitawa - Ayyukan Shamaki Ya Dogaro Kan Ikon Lalacewa
Factor
Tasiri kan WVTR
Gudanar da Ayyuka
PTFE crystallinity na ciki
Matsakaicin tushe
Kafaffen – ba za a iya sarrafawa a samfur ba
Micropores daga rashin kammala sintering
Babban (yana ƙirƙira gajerun hanyoyi)
Haɓaka bayanin martaba na sintering - sanyaya hankali a hankali, mafi girman zafin jiki
Microcracks daga haɓakar haɓakar thermal rashin daidaituwa
Mai girma sosai
Shafi mai yawa, matsakaicin FEP Layer, sanyaya hankali
Fiber wicking (wanda bai cika cika ba)
Babban
Tabbatar da cikar ciki - taimako mara amfani don yadudduka masu kauri
Kauri mai rufi (launi ɗaya)
Ƙananan
Ba tasiri shi kaɗai
Multi-Layer shafi
Babban (yana rufe lahani)
Ƙayyade 2-4 wucewar impregnation
Lamellar fillers (mica, gilashin flakes)
Yayi girma sosai (tasirin labyrinth)
Ƙara 10-20 wt%, inganta watsawa
Cikak + haɗe-haɗe da yawa
Mafi girma (<10 g/m² · rana)
Mafi kyau don aikace-aikacen shinge mai mahimmanci
Hanya ta ƙarshe: Lokacin da aka yi amfani da tef ɗin manne PTFE don hatimi mai ƙarfi, lahani da aka haifar da tsari (micropores, cracks, fiber wicking) ya kasance babban rauni na iyawar shinge. Ana samun ingantaccen hatimin hatimi ta hanyar jiyya mai ƙima gami da shafi mai yawa da gyaran filler . PTFE composite tef yana aiki azaman abin dogaro Multi-aiki shãmaki karkashin matsananci yanayi bukatar high zafi juriya, lalata juriya, zafi kwanciyar hankali, da kuma maras sanda saki yi lokaci guda - amma ba a matsayin tsayayye matsananci-high shãmaki kamar karfe tsare ko PVDC.
A taƙaice , abin da ke hana ruwa tururi mallakar PTFE m tef ba a ƙaddara ta PTFE ta hydrophobicity kadai. PTFE na ciki shine shinge mai matsakaici (WVTR 5-10 g/m² · rana don fim mara lahani). Koyaya, kaset masu amfani suna shan wahala daga micropores, microcracks (daga haɓaka haɓakar thermal tare da fiberglass), da wicking fiber - haɓaka WVTR zuwa 50-200 g / m² · rana.
Don cimma ƙananan WVTR (<15 g / m² · rana), ƙayyade shafi mai yawa (3+ impregnation passes) da / ko gyare-gyaren filler (10-20 wt% mica ko gilashin gilashi). Tasirin labyrinth daga masu cikawa yana tilasta tururin ruwa don ɗaukar hanyoyin iska, yana rage watsawa sosai. Koyaya, babban lodin filler na iya rage sassauƙa da aikin rashin tsayawa - ana buƙatar ma'auni.
Ana buƙatar ƙaramin-WVTR PTFE tef ɗin manne don rufewa mai raɗaɗi? Aokai PTFE yana ba da maki mai rufi da yawa da gyare-gyare tare da bayanan gwajin WVTR da aka rubuta. Tuntube mu tare da WVTR da ake buƙata, zafin aiki, da buƙatun sassauci.
Idan kuna buƙatar cikakkun sigogin fasaha, jagorar aikace-aikacen, da mafita na musamman don cikakken fayil ɗin samfurin mu gami da PTFE high-zazzabi zane, PTFE high-zazzabi m tef, PTFE raga na'ura bel, sumul fuser bel, guda-gefe PTFE masana'anta, high-zazzabi resistant conveyor bel da heatproof fiberglass : Tufafi, don Allah tuntube mu.
