I. Mawu ndi Matanthauzo

Kuwala kwa dzuwa kuli ndi kuwala kwa ultraviolet (UV) kochuluka, komwe kumakhala ndi mafunde a pafupifupi 290-460 nm, zomwe zimavulaza zinthu zamitundu. Kuwala koopsa kwa UV kumeneku kumapangitsa kuti mamolekyu amitundu awole ndikuzimiririka kudzera mu redox reaction ya mankhwala. Kugwiritsa ntchito ma UV absorbers kumatha kupewa kapena kuchepetsa kuwonongeka kwa kuwala kwa UV pazinthu zotetezedwa.

Choyatsira UV ndi choyatsira kuwala chomwe chimayamwa gawo la UV la kuwala kwa dzuwa ndi magwero a kuwala kwa fluorescent popanda kusintha kulikonse. Pansi pa kuwala kwa dzuwa ndi kuwala kwa fluorescent, mapulasitiki ndi ma polima ena amakumana ndi zochitika za auto-oxidation chifukwa cha mphamvu ya kuwala kwa UV, zomwe zimapangitsa kuti polima iwonongeke komanso iwonongeke, zomwe zimapangitsa kuti mawonekedwe ake asawoneke bwino komanso mawonekedwe ake asawonekere bwino. Kuwonjezera ma UV absorbers kumayamwa mosankha kuwala kwa UV komwe kumakhala ndi mphamvu zambiri, n’kukusintha kukhala mphamvu yopanda vuto yomwe imatulutsidwa kapena kugwiritsidwa ntchito. Popeza ma polima osiyanasiyana ali ndi mafunde osiyanasiyana a UV omwe amachititsa kuwonongeka, ma UV absorbers osiyanasiyana amayamwa mafunde osiyanasiyana a kuwala kwa UV. Chifukwa chake, choyatsira UV choyenera chiyenera kusankhidwa kutengera mtundu wa polima yomwe imagwiritsidwa ntchito.

II. Kugawa ndi Ntchito za Ma Ultraviolet Absorbers

Ma absorber a Ultraviolet ayenera kukwaniritsa zofunikira izi:

① Imatha kuyamwa kuwala kwa ultraviolet mwamphamvu (makamaka kuwala kwa ultraviolet komwe kumakhala ndi mafunde a 290 ~ 400nm); ② Imakhala ndi kutentha kwabwino ndipo sisintha chifukwa cha kutentha ngakhale panthawi yokonza, yokhala ndi kutentha kochepa; ③ Imakhala ndi mankhwala abwino ndipo sidzagwirizana ndi zinthu zomwe zili mu chinthucho; ④ Imatha kusokonekera bwino ndipo imatha kufalikira mofanana mu chinthucho popanda kuphuka kapena kutuluka; ⑤ Choyamwa chokha chimakhala ndi kuwala kwa photochemical, sichiwola, ndipo sichisintha mtundu; ⑥ Ndi yopanda utoto, yopanda poizoni, komanso yopanda fungo; ⑦ Imatsukidwa; ⑧ Ndi yotsika mtengo komanso imapezeka mosavuta.

Ma Benzotriazole UV absorbers ndi omwe amagwiritsidwa ntchito kwambiri ku China pakadali pano, koma ma triazine UV absorbers amasonyeza bwino kwambiri kuposa ma benzotriazoles. Ma Triazine absorbers ali ndi mphamvu zabwino kwambiri zoyamwa UV, komanso zabwino zina, zomwe zimapangitsa kuti azigwiritsidwa ntchito kwambiri mu ma polima. Amasonyeza kukhazikika kwa kutentha, kukhazikika bwino pakukonza, komanso kukana asidi. Mu ntchito zenizeni, ma triazine UV absorbers amasonyeza mphamvu yogwirizana kwambiri ndi ma amine light stabilizers oletsedwa; akagwiritsidwa ntchito pamodzi, amapereka zotsatira zabwino kuposa akagwiritsidwa ntchito payekhapayekha.

III. Zokometsera zingapo zodziwika bwino za ultraviolet

(1) Zotsatira za o-nitroaniline ndi p-cresol

Imawoneka ngati makhiristo opanda mtundu kapena achikasu otumbululuka. Imasungunuka mu zinthu zambiri zachilengedwe monga petulo, benzene, ndi acetone. Imasungunuka pang'ono m'madzi ndipo siisungunuka ndi ma alkali kapena ma acid ambiri. Imatha kuchitapo kanthu ndi ma ayoni achitsulo cholemera kuti ipange mchere. Imatha kuyamwa kuwala kwa ultraviolet ndi mafunde a 270-280 nm. Malo ake osungunuka ndi 130-131℃.

Amagwiritsidwa ntchito makamaka mu utomoni monga polyester, polyester yopangidwa ndi chlorinated, cellulose acetate, polyvinyl chloride, polystyrene, plexiglass, ndi polyacrylonitrile. Amakhala okhazikika bwino muzinthu zowonekera kuposa zinthu zamitundu. Mlingo wazinthu zomalizidwa ndi ≤0.5%.

(2) 2-Hydroxy-4-methoxybenzophenone (UV-9)

Ufa wa kristalo wotumbululuka wachikasu kapena woyera. Kuchulukana 1.324 g/cm³. Malo osungunuka 62-66℃. Malo otentha 150-160℃ (0.67 kPa), 220℃ (2.4 kPa). Sungunuka mu zosungunulira zambiri zachilengedwe monga acetone, ketones, benzene, methanol, ethyl acetate, methyl ethyl ketone, ndi ethanol; susungunuka m'madzi. Kusungunuka (g/100g, 25℃) mu zosungunulira zina ndi motere: benzene 56.2, n-hexane 4.3, ethanol (95%) 5.8, carbon tetrachloride 34.5, styrene 51.2, DOP 18.7.

Monga choyamwa UV, chimagwiritsidwa ntchito pa mapulasitiki osiyanasiyana monga polyvinyl chloride, polyvinylidene chloride, polymethyl methacrylate, unsaturated polyester, ABS resin, ndi cellulose resin. Kutalika kwa mafunde oyamwa ndi 280 ~ 340nm, ndipo mlingo wamba ndi 0.1% ~ 1.5%. Chimakhala ndi kutentha kwabwino ndipo sichimawola pa 200℃. Chogulitsachi sichimayamwa kuwala kulikonse, zomwe zimapangitsa kuti chikhale choyenera zinthu zowala komanso zowonekera. Chingagwiritsidwenso ntchito mu utoto ndi rabara yopangidwa.

(3) 2-Hydroxy-4-n-octyloxybenzophenone (UV-531)

Ufa wa kristalo wotumbululuka kapena woyera. Kuchulukana 1.160 g/cm³ (25℃). Malo osungunuka 48~49℃. Sungunuka mu acetone, benzene, ethanol, ndi isopropanol; sungunuka pang'ono mu dichloroethane; susungunuka m'madzi. Kusungunuka (g/100g, 25℃) mu zosungunulira zina ndi: acetone 74, benzene 72, methanol 2, ethanol (95%) 2.6, n-heptane 40, n-hexane 40.1, madzi 0.5.

Monga choyamwa UV, chimayamwa kwambiri kuwala kwa ultraviolet ndi mafunde a 270-330 nm. Chingagwiritsidwe ntchito mu mapulasitiki osiyanasiyana, makamaka polyethylene, polypropylene, polystyrene, ABS resin, polycarbonate, ndi polyvinyl chloride. Chimagwirizana bwino ndi ma resin komanso chosasinthasintha kwambiri. Mlingo wamba ndi 0.1% mpaka 1%. Chimakhala ndi mphamvu yabwino yogwirizana ikagwiritsidwa ntchito ndi 4,4-thiobis (6-tert-butyl-p-cresol) yochepa. Chogulitsachi chingagwiritsidwenso ntchito ngati chokhazikika cha kuwala m'zophimba zosiyanasiyana.

(4) 2-(2′-hydroxy-3′,5′-di-tert-phenyl)-5-chlorobenzotriazole (UV-327) ndi chinthu choyamwa UV chomwe chili ndi makhalidwe ofanana ndipo chimagwiritsidwa ntchito ndi benzotriazole UV-326. Chimayamwa kwambiri kuwala kwa ultraviolet ndi mafunde a 270 ~ 380nm, chili ndi kukhazikika kwabwino kwa mankhwala, komanso kusasinthasintha kochepa. Chimagwirizana bwino ndi polyolefins. Ndi choyenera kwambiri pa polyethylene ndi polypropylene. Kuphatikiza apo, chingagwiritsidwenso ntchito mu polyvinyl chloride, polymethyl methacrylate, polyoxymethylene, polyurethane, unsaturated polyester, ABS resin, epoxy resin, cellulose resin, ndi zina zotero. Chogulitsachi chili ndi kukana kutentha kwambiri, kusambitsidwa, kukana mpweya, komanso kusunga mphamvu zamagetsi. Chili ndi mphamvu yogwirizana kwambiri ikagwiritsidwa ntchito ndi ma antioxidants. Chimagwiritsidwa ntchito kukonza kukhazikika kwa thermo-oxidative kwa zinthu.

(5) Resorcinol monobenzoate ndi ufa woyera wa kristalo. Malo osungunuka 132 ~ 135℃. Kuchuluka kwa mafuta ndi 0.68 g/cm³ (20%). Amasungunuka mu acetone ndi ethanol, amasungunuka pang'ono mu benzene, madzi, n-heptane, ndi zina zotero. Monga chokhazikika cha kuwala kwa UV, magwiridwe ake ndi ofanana ndi a benzophenone-based light stabilizers. Amagwiritsidwa ntchito kwambiri mu polyvinyl chloride, cellulose resin, ndi polystyrene, nthawi zambiri pamlingo wa 1% mpaka 2%.