Chifukwa cha kupanga urea formaldehyde resin, kukula kwa makampani a melamine kwachitika mwachangu.The kafukufuku chikalata choyamba lipoti kaphatikizidwe utomoni melamine mu 1933. America Cyanamide Company anayamba kupanga ndi kugulitsa melamine ufa laminates ndi zokutira etc mu 1939. Mu 1950s ndi 1960s, Japan anazindikira zonse mafakitalemelamine akamaumba pawiri.M'zaka za m'ma 1960, China idayamba kuyambitsa ukadaulo wopanga melamine.Pambuyo pa chitukuko chazaka zambiri, mphamvu yopangira zinthu za melamine tsopano ndiyokwera kwambiri padziko lonse lapansi, zomwe zikuwerengera 80 9/6 ya msika wapadziko lonse lapansi.
Kuti mudziwe zambiri za ufa wa melamine, tiyeni tiwone kaye kupanga melamine ufa poyamba.
Zopangira zazikulu za mankhwala a melamine ndi makina opangira melamine, omwe amadziwikanso kuti melamine formaldehyde resin powder kapena melamine powder.Zopangira zazikulu za melamine ufa ndi melamine resin yokhala ndi reactivity yayikulu komanso yolumikizana.Utomoni wa melamine ndi polima wa dandelion wapamwamba kwambiri wopangidwa ndi mankhwala a melamine ndi yankho lamadzi la formaldehyde pansi pamikhalidwe yovuta.Zimene zimachitika kawirikawiri ikuchitika mu riyakitala okonzeka ndi oyambitsa, Kutentha ndi condensing unit, zambiri masitepe awiri.
1. Gawo loyamba ndikuyankha kowonjezera.Choyamba, onjezerani 37% yankho lamadzi la formaldehyde pachotengera ndikusintha pH kukhala 7-9 kuti mupeze sing'anga kapena yofooka yamchere yamchere.Kenaka yonjezerani mlingo woyenera wa melamine kuti mupange moore formaldehyde ndi melamine pakati pa 2 ndi 3. Kutentha kwa riyakitala kunasinthidwa kotero kuti pang'onopang'ono kumatenthedwa mpaka 60-85 ° C. Panthawiyi, formaldehyde ndi melamine zinatsekedwa ndi methylolation reaction. , ndipo mzere wa melamine oligomer wokhala ndi 1 mpaka 6 magulu a methylol anapangidwa.Zomwe zili pamwambazi ndizovuta kwambiri.Kuchuluka kwa formaldehyde kumakhala kosavuta kupanga polymethylol melamine.
2. Gawo lachiwiri ndi condensation reaction.Pansi pa kutentha kwambiri, methylol melamine yothamanga kwambiri imapangidwanso etherified kapena polycondensed kuti ipange utomoni wophatikizika wokhala ndi chomangira cha methylene kapena chomangira cha dimethylene ether.ndi intramolecular kapena ma molekyulu m'malo a acidic sing'anga.Pamene kuchuluka kwa gulu la methylol kuli kochepa, mgwirizano wa methylene nthawi zambiri umakhala waukulu;mu utomoni wa manyuchi, mgwirizano wa dimethylene ether nthawi zambiri umapangidwa, ndipo mgwirizano wa methylene umapangidwa.Kuchuluka kwa kuchuluka kwa condensation kwa polycondensation reaction, kumachepetsa kusungunuka kwamadzi kwa melamine formaldehyde resin solution komanso kukhathamira kwakukulu.
M'machitidwe omwe ali pamwambapa, kulemera kwa mamolekyu a chinthu chomaliza kumatsimikiziridwa ndi momwe zinthu zilili, komanso kusungunuka kwamadzi kwa mankhwalawa kumasinthidwanso kwambiri.Mafomu azinthu amapezeka kwambiri kuchokera ku utomoni kupita ku zolimba zosasungunuka komanso zosasungunuka komanso zosasungunuka.Njira yothetsera utomoni imakhala yosakhazikika bwino ndipo siyenera kusungidwa.Pakupanga kwenikweni, nthawi zambiri amagwiritsidwa ntchito ngati gawo lapansi komanso zinthu zosasinthika monga d-cellulose, zamkati zamatabwa, silika, zopaka utoto zimawonjezeredwa.Amapangidwa kukhala powdery olimba omwe amatchedwa melamine ufa ndi kupopera kuyanika mpira mphero.
Huafu Chemicals ndi fakitale yopangamelamine utomoni ufa.Ngati mukufuna, lemberaniEmail : melamine@hfm-melamine.com
Nthawi yotumiza: Sep-20-2019