UV chemistry yoyendetsedwa ndi madzi (WB) yawonetsa kukula kwakukulu m'misika yamitengo yamkati chifukwa ukadaulowu umapereka magwiridwe antchito abwino kwambiri, mpweya wochepa wotulutsa solvent komanso magwiridwe antchito abwino kwambiri. Makina ophimba a UV amapatsa ogwiritsa ntchito phindu la kukana mankhwala ndi kukanda bwino, kukana bwino kwa block, ma VOC ochepa kwambiri komanso malo ochepa osungiramo zida. Makina awa ali ndi zinthu zomwe zimafanana bwino ndi makina a urethane okhala ndi magawo awiri popanda zovuta za crosslinkers zoopsa komanso nkhawa za moyo wa mphika. Dongosolo lonseli ndi lotsika mtengo chifukwa cha liwiro lokwera la kupanga komanso ndalama zochepa zamagetsi. Ubwino womwewo ukhoza kukhala wopindulitsa pakugwiritsa ntchito kunja kwa fakitale kuphatikiza mafelemu a zenera ndi zitseko, siding ndi ntchito zina zopangira. Magawo amsika awa nthawi zambiri amagwiritsa ntchito ma emulsion a acrylic ndi polyurethane dispersions chifukwa ali ndi kuwala kwabwino komanso kusunga mitundu, ndipo amasonyeza kulimba kwapamwamba. Mu kafukufukuyu, ma resin a polyurethane-acrylic okhala ndi magwiridwe antchito a UV ayesedwa malinga ndi zomwe makampani amagwiritsa ntchito pakugwiritsa ntchito matabwa amkati ndi akunja.
Mitundu itatu ya zokutira zochokera ku solvent imagwiritsidwa ntchito kwambiri m'mafakitale amatabwa. Nitrocellulose lacquer nthawi zambiri ndi chosakaniza cha nitrocellulose ndi mafuta kapena ma alkyd okhala ndi mafuta ochepa. Zophimbazi zimauma mwachangu ndipo zimakhala ndi mphamvu yowala kwambiri. Nthawi zambiri zimagwiritsidwa ntchito m'mipando ya m'nyumba. Zili ndi vuto la chikasu pakapita nthawi ndipo zimatha kusweka. Zimakhalanso ndi kukana mankhwala. Ma lacquer a nitrocellulose ali ndi ma VOC ambiri, nthawi zambiri amakhala 500 g/L kapena kupitirira apo. Ma lacquer opangidwa kale ndi osakaniza a nitrocellulose, mafuta kapena ma alkyd okhala ndi mafuta, ma plasticizer ndi urea-formaldehyde. Amagwiritsa ntchito chothandizira chofooka cha asidi monga butyl acid phosphate. Zophimbazi zimakhala ndi moyo wa alumali wa pafupifupi miyezi inayi. Zimagwiritsidwa ntchito m'mipando yaofesi, ya mabungwe ndi ya m'nyumba. Ma lacquer opangidwa kale ndi otsutsana ndi mankhwala kuposa ma lacquer a nitrocellulose. Alinso ndi ma VOC ambiri. Ma varnish osinthika ndi osakaniza a ma alkyd okhala ndi mafuta, urea formaldehyde ndi melamine. Amagwiritsa ntchito chothandizira champhamvu cha asidi monga p-toluene sulfonic acid. Amakhala ndi moyo wa mphika wa maola 24 mpaka 48. Amagwiritsidwa ntchito m'makabati akukhitchini, mipando yaofesi ndi mipando ya m'nyumba. Ma varnish osinthira ali ndi mawonekedwe abwino kwambiri amitundu itatu ya zokutira zochokera ku solvent zomwe zimagwiritsidwa ntchito popanga matabwa amafakitale. Ali ndi ma VOC ambiri komanso utsi wa formaldehyde.
Ma emulsion a acrylic odzigwirizanitsa okha ndi madzi komanso ma polyurethane dispersions angakhale njira zabwino kwambiri m'malo mwa zinthu zopangidwa ndi zosungunulira zomwe zimagwiritsidwa ntchito pamatabwa a mafakitale. Ma emulsion a acrylic amapereka mankhwala abwino kwambiri komanso oteteza ku ma block, kuuma kwapamwamba, kulimba kwambiri komanso kupirira nyengo, komanso kumamatira bwino pamalo opanda mabowo. Amakhala ndi nthawi youma mwachangu, zomwe zimathandiza kuti kabati, mipando kapena opanga zinthu zomangira azitha kugwira ziwalozo atangogwiritsa ntchito. Ma PUD amapereka kukana kwabwino kwambiri kwa kukwawa, kusinthasintha, komanso kukana kukanda ndi kuwonongeka. Ndi othandizana bwino ndi ma emulsion a acrylic kuti akonze mawonekedwe a makina. Ma emulsion a acrylic ndi ma PUD onse amatha kuchitapo kanthu ndi mankhwala olumikizana monga polyisocyanates, polyaziridine kapena carbodiimides kuti apange zokutira za 2K zokhala ndi mawonekedwe abwino.
Zophimba za UV zogwiritsidwa ntchito m'madzi zakhala zodziwika bwino pa ntchito zamatabwa a mafakitale. Opanga makabati a kukhitchini ndi mipando amasankha zophimba izi chifukwa zimakhala ndi mphamvu zabwino kwambiri zotsutsana ndi makina, mphamvu zabwino kwambiri zogwiritsira ntchito komanso mpweya wochepa kwambiri wa solvent. Zophimba za UV za WB zimakhala ndi mphamvu zabwino kwambiri zotsutsana ndi block nthawi yomweyo zitakonzedwa, zomwe zimathandiza kuti ziwalo zophimbidwazo zisungidwe, kupakidwa ndi kutumizidwa nthawi yomweyo kuchokera pamzere wopanga popanda nthawi yokwanira yopangira kuuma. Kukula kwa kuuma mu zophimba za UV za WB ndi kwakukulu ndipo kumachitika mumasekondi. Kukana kwa mankhwala ndi banga kwa zophimba za WB UV ndikopambana kuposa ma varnish osinthika okhala ndi solvent.
Zophimba za UV za WB zili ndi ubwino wambiri. Ngakhale kuti ma oligomer a UV olimba 100% nthawi zambiri amakhala ndi kukhuthala kwakukulu ndipo ayenera kuchepetsedwa ndi zosungunulira zosinthika, ma PUD a WB UV ndi otsika kukhuthala, ndipo kukhuthala kumatha kusinthidwa ndi zosinthira zachikhalidwe za WB rheology. Ma PUD a WB UV poyamba amakhala ndi kulemera kwakukulu kwa mamolekyulu ndipo samapanga kulemera kwa mamolekyulu chifukwa amachira kwambiri ngati zophimba za UV zolimba 100%. Chifukwa chakuti amakhala ndi kufooka pang'ono kapena alibe konse pamene akuchira, ma PUD a WB UV amakhala ndi kumamatira bwino kwambiri kuzinthu zambiri. Kuwala kwa zophimba izi kumawongoleredwa mosavuta ndi zinthu zachikhalidwe zomangira. Ma polima awa akhoza kukhala olimba kwambiri komanso osinthasintha kwambiri, zomwe zimapangitsa kuti akhale oyenera kwambiri zophimba zakunja zamatabwa.
Nthawi yotumizira: Marichi-07-2024
