Melamine-formaldehyde utomoni (MFR) ndi thermosetting amino utomoni ndi kuuma kwabwino, kukhazikika kwa kutentha, ndi kuwonekera. Poyerekeza ndi urea-formaldehyde resin (UF), utomoni wa MF umalimbana bwino ndi madzi komanso kukana nyengo. Chifukwa chake, amagwiritsidwa ntchito kwambiri pazovala zapanja zakunja, zigawo zokongoletsa pansi zamatabwa ndi zida za veneer. Komabe, zofooka monga kuphulika kwakukulu, kusweka kosavuta, ndi nthawi yochepa yosungiramo utomoni wa melamine formaldehyde umachepetsa ntchito yake. MF utomoni nthawi zambiri ntchito kukonzekera impregnated zomatira filimu pepala. Plywood ndi bolodi loyang'anizana ndi pepala lomatira loyimbidwa pamodzi limatchedwa ma board achilengedwe. Amakondedwa ndi ogula chifukwa cha kusavala kwawo, kutetezedwa kwa madzi, ndi mitundu yosiyanasiyana.
Komabe, chinyontho cha chilengedwe chikasintha, zinthu zachilengedwe zimatha kutupa kapena kuchepa, zomwe zimapangitsa kuti pakhale kupsinjika kwamkati. Pamwamba pa utomoni wa MF ndi wosasunthika komanso wosasinthika bwino, ndipo sachedwa kusweka ndi kupsinjika. Chifukwa chake, kuwongolera kusinthika kwa utomoni wa MF ndikuwongolera vuto la brittleness ndiye makiyi othetsera vuto la kusweka kwa utomoni ndikuwongolera kukongoletsa kwake. Nkhaniyi ikufotokoza mwachidule momwe kafukufukuyu akuyendera pakusintha kolimba kwa utomoni wa MF, ndi cholinga chopereka chitsogozo chaukadaulo komanso luso lothana ndi vuto la brittleness la utomoni wa MF.
1. Makhalidwe a MF
MF utomoni ndi triazine mphete polima pawiri wopangidwa ndi condensation wa melamine ndi formaldehyde ndipo olumikizidwa ndi methylene kapena ether zomangira. Lili ndi mankhwala okhazikika komanso okhazikika. Mapangidwe a utomoni wa MF amagawidwa m'magawo awiri: gawo loyamba ndikuwonjezera kwa melamine ndi formaldehyde. Pansi pazandale kapena zamchere, melamine imakumana ndi hydroxymethylation kuti ipange ma 9 hydroxymethylmelamines osiyanasiyana. Gawo lachiwiri ndi condensation reaction. Melamine imakhudzidwa ndi methylolated melamine, kapena methylolated melamine imadzilimbitsa yokha kuti ipange oligomers olumikizidwa ndi methylene ndi ether bond. M'malo okhala ndi pH ya 7 mpaka 8, kulumikizana kwa mlatho wa methylene kumalamulira; m'malo okhala ndi pH yamtengo wapatali kuposa 9, ma ether bond bond amatha kupanga.
Pambuyo polumikizana ndi kuchiritsa kwa MF utomoni, zokutira zowoneka bwino zomwe sizimva kuvala, acid ndi alkali zosamva zimatha kupezeka. Ngakhale kuti zokutira zochiritsidwa zimakhala zolimba kwambiri, zimakhalanso zowonongeka. Chifukwa chachikulu ndikuti utomoni wa MF uli ndi mphete zambiri za triazine zolumikizidwa ndi magulu a methylene. Mphete za triazine zimakhala zokhazikika kwambiri pansi pa zochitika zomwe zimakhudzidwa ndipo zimakhala zovuta kusokoneza ndi kuyamwa mphamvu zowonongeka. Zomangira za methylene zokha zimatha kutenga mphamvu zambiri, zomwe zimapangitsa kuti ma methylene athyoke ndikuwonetsa brittleness. Kuchiza kosakwanira kwa utomoni wa MF kungayambitse kusweka kwa utomoni. Popeza machiritso a utomoni amapezeka makamaka pakati pa magulu a hydroxyl, magulu ena a hydroxyl omwe sanatenge nawo gawo pakukoketsa amakhalabe muutomoni atachiritsidwa. Magulu a hydroxyl awa ali ndi hygroscopicity. Chinyezi cha chilengedwe chikamasintha mobwerezabwereza, magulu a hydroxyl aulere amayendera ma hygroscopic ndi desorption ndipo pang'onopang'ono amabweretsa kupsinjika, zomwe zimapangitsa ming'alu mu zokutira utomoni ndikuwononga kwambiri mawonekedwe ndi magwiridwe antchito a chinthucho.
Kusinthasintha kwa utomoni wa MF kumatha kupitsidwanso bwino pochepetsa kachulukidwe wolumikizana ndi utomoni wa MF ndikukulitsa utali wake wosinthika. Komabe, kuchepetsedwa kwa kachulukidwe kolumikizira kumatanthauza kuti mawonekedwe olimba a mphete ya triazine mu utomoni amamwazikana. Chifukwa chake, kulimba kwapamwamba komanso kukana kwa MF resin kumakhudzidwa mosiyanasiyana. Pochita kusintha kolimba, kusamala kuyenera kuchitidwa kuti musunge kuuma kwa utomoni wa MF komanso kuti musawononge mawonekedwe ake apamwamba. Kusankha njira yoyenera yosinthira kuti musinthe kusinthika kwa utomoni wa MF ndikofunikira kwambiri pakukulitsa kuchuluka kwa ntchito ya utomoni wa MF.
2. Toughening kusinthidwa njira MF utomoni
Toughening kusinthidwa nthawi zambiri ntchito kukhathamiritsa mphamvu ya okhwima mtanda ogwirizana ma polima kusintha kukana zotsatira ndi kukana kutopa wa polima popanda kuwononga stiffness choyambirira ndi dimensional bata la polima. Njira zosinthira toughening zoyenera MF utomoni zitha kugawidwa m'mitundu iwiri, kutanthauza kusinthidwa kolimba kwakunja ndikusintha kwamkati mkati. Kusintha kwamphamvu kwakunja kumatanthawuza kuwonjezera kulimbikitsa magulu agawo ku utomoni wa MF pophatikizana kuti apange mawonekedwe olumikizana ndi utomoni wa MF kuteteza mphete za triazine kuti zisayandikirane kuti zikwaniritse cholinga cholimba. Njira zomwe zimagwiritsidwa ntchito molimbika kunja kwa MF utomoni ndi monga:
1) Onjezani nano-SiO2, nano-cellulose ndi nanoparticles zina;
2) Gwiritsani ntchito ma polima osinthasintha atalitali monga ma polyethylene glycol copolymers kuti apange maukonde a polima a interpenetrating (IPNS) mu MF resin;
3) Gwiritsani ntchito zida za utomoni monga polyvinyl chloride kulumikiza ma resin a MF palimodzi kuti mulimbikitse kukhazikika kwa utomoni.
Kusintha kwa mkati kumasintha mawonekedwe a mamolekyu a MF utomoni potenga nawo gawo pakuchiritsa kwa utomoni wa MF, kukulitsa kulumikizana kosinthika pakati pa mphete za triazine, ndikuchepetsa kachulukidwe wolumikizirana kuti akwaniritse zolimba. Njira zochepetsera thupi ndi izi:
1) Yambitsani mamolekyu a unyolo wautali pakati pa ma triazine mphete za MF resin kuti abalalitse mawonekedwe olimba;
2) Gwiritsani ntchito silikoni kukulitsa kulumikizana kosavuta pakati pa MF utomoni;
3) Tsekani gulu logwira ntchito la hydroxyl la MF resin ndikuchepetsa kuphatikizika kolumikizana kwa utomoni. Zomwe zimagwiritsidwa ntchito nthawi zambiri zosinthira mkati zimaphatikizamo mowa wa polyvinyl, polyurethane, caprolactam, ndi zina.
3. Zofunikira zapadera za MF resin for impregnation
Pali njira zambiri zowumitsira utomoni wa MF, koma si onse omwe ali oyenera kuyimilira utomoni wa MF. The toughening kusinthidwa kwa impregnating MF utomoni ayenera kusintha mmene kupanga zomatira filimu pepala, kotero ili ndi zofunika zina zapadera. Pogwiritsa ntchito MF utomoni impregnation, sitiyenera kuganizira kukana ming'alu, kuvala kukana ndi kusinthasintha pambuyo kuchiritsa utomoni, komanso kulabadira fluidity, permeability ndi chisanadze kuchiritsa digiri ya kusinthidwa utomoni pamaso kuchiritsa.
Kusakwanira kwa madzi a MF utomoni kumayambitsa maluwa owuma pamwamba pa filimu yomatira yomata pamapepala, kutulutsa mawanga oyera opaque pamwamba pa chinthucho, ndikupanga zolakwika. Kusakwanira bwino kwa utomoni wa MF kungayambitse kusamalidwa kokwanira, zomwe zimapangitsa kuti pakhale kusowa kwa guluu kapena malo osafananira pamalopo. Inorganic nano-kuvala zosagwira zipangizo akhoza kuonjezera kulimba ndi kuvala zosagwira katundu wa MF utomoni, koma nthawi yomweyo iwo adzawonjezera mamasukidwe akayendedwe a MF utomoni ndi kuchepetsa fluidity wa utomoni, potero zimakhudza impregnation ntchito MF utomoni. Tinapeza kuti mamasukidwe akayendedwe a MF utomoni amawonjezeka ndi kuchuluka kwa kuvala zosagwira filler nano-SiO2 (HTSi-03). Kukhuthala kwa mawonekedwe osinthika a MF resin system anali 20.9 s (25 ° C), ndipo mawonekedwe olumikizana pakati pa MF utomoni ndi pepala lokongoletsera adakula kuchokera ku 5 ° mpaka 30 °. Panthawi imodzimodziyo, kunyowa kumachepa, kotero kuti MF utomoni sungathe kudzaza mipata mu pepala lokongoletsera, ndipo kuvala kosavala sikungathe kuteteza mokwanira, zomwe zimapangitsa kuchepa kwa kukana kuvala.
Kutsika kocheperako kwa utomoni wa MF kumapangitsa kuti pakhale kutentha kwambiri panthawi ya veneer, zomwe zimapangitsa kuti maluwa onyowa asokoneze magwiridwe antchito a pamwamba. Polyhydroxyl mowa modifiers angathe kuonjezera kusinthasintha kwa MF utomoni, koma ena hydrophilicity wa polyhydroxyl modifiers si kothandiza kuyanika impregnated pepala zomatira filimu, potero kuchepetsa chisanadze kuchiritsa digiri ya MF utomoni. Izi zimabweretsa mavuto monga kuyamwa kwa chinyezi ndi kumamatira kwa pepala lopaka filimu yomata komanso kuvutikira kupeza. Nthawi yomweyo, pepala lomatira lopangidwa ndi filimu yokhala ndi digiri yotsika yochiritsira imatulutsa madzi ambiri panthawi yowotcha, zomwe zimapangitsa kuti pakhale mavuto monga kuchepa kwa voliyumu ya zomatira komanso kusweka kwa utomoni, zomwe zimakhudza magwiridwe antchito.
Chifukwa chake, poganizira zovuta zenizeni zopanga, MF utomoni toughening agent yomwe imagwiritsidwa ntchito poimiritsa iyenera kugwiritsa ntchito chosinthira chokhala ndi mamolekyulu otsika, otsika kwambiri a hydroxyl, komanso kuchitapo kanthu kwakukulu kuti achepetse kukhudzidwa kwa chosinthira pamadzimadzi ndi kuchiritsa kale kwa utomoni wa MF. Nthawi yomweyo, wothandizira wolimbitsa thupi amafunikira kuti agwirizane ndi machiritso a utomoni wa MF womwe umagwiritsidwa ntchito pakuyimbidwa, ndikusungabe kusintha kwake pambuyo pochiritsa kotentha.
Kusintha kwa utomoni wa MF pakuyimbidwa kuyenera kuganizira zinthu zambiri nthawi imodzi. Kusintha koyenera kumakulitsa kusinthasintha kwa utomoni wa MF popanda kusokoneza kukana kuvala pamwamba, kusungunuka kapena kuchiritsa chisanadze. Choncho, tikulimbikitsidwa kuti kafukufuku wamtsogolo wokhudza kusintha kwa MF resin ayenera kuchitidwa kuchokera kuzinthu zitatu zotsatirazi.
1) Kutengera kapangidwe ka MF utomoni, vuto la brittleness la utomoni wa MF litha kuthetsedwa posintha makulidwe olumikizirana a MF resin.
2) Kuphatikiza njira zosiyanasiyana zolimbikitsira, yambitsani mawonekedwe osinthika a unyolo omwe ali ndi magulu ochita ntchito zambiri kukhala utomoni wa MF, ndikuwonjezera kusinthasintha kwa utomoni wa MF kudzera mumgwirizano wakuphatikizika kwakuthupi ndi machitidwe amankhwala.
3) Pakuwona kufewetsa njira yopangira ndikupulumutsa ndalama, sankhani zosintha zogwira mtima kwambiri zoyenera kupanga mafakitale.
Zambiri zokhudza SINOYQX modified melamine formaldehyde resin, chonde titumizireni imelo: [email protected] , kapena titumizireni uthenga pa: +86-28-8411-1861.
Zithunzi ndi zolemba zina zidapangidwanso kuchokera pa intaneti, ndipo kukopera ndi kwa wolemba woyamba. Ngati pali kuphwanya kulikonse, chonde titumizireni kuti tifufute.