Cellulose ndi polysaccharide yomwe imapanga mitundu yosiyanasiyana ya ma ether osungunuka m'madzi. Ma cellulose thickeners ndi ma polima osungunuka m'madzi omwe si a ionic. Mbiri yake yogwiritsidwa ntchito ndi yayitali kwambiri, zaka zoposa 30, ndipo pali mitundu yambiri. Amagwiritsidwabe ntchito mu utoto wonse wa latex ndipo ndi omwe amagwiritsidwa ntchito kwambiri mu ma thickeners. Ma cellulose thickeners ndi othandiza kwambiri m'madzi chifukwa amalimbitsa madzi okha. Mu makampani opanga utoto, ma cellulose thickeners omwe amagwiritsidwa ntchito kwambiri ndi awa:methyl cellulose (MC), hydroxyethyl cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), hydroxypropyl cellulose (HPC),hydroxypropyl methyl cellulose (HPMC)ndi hydroxyethyl cellulose yosinthidwa ndi hydrophobically modified (HMHEC). HEC ndi polysaccharide yosungunuka m'madzi yomwe imagwiritsidwa ntchito kwambiri pakukhuthala kwa utoto wa latex wopangidwa ndi matt ndi semi-gloss. Zokhuthala zimapezeka m'mitundu yosiyanasiyana ya viscosity ndipo zokhuthala zokhala ndi cellulose iyi zimakhala ndi mitundu yabwino kwambiri komanso kukhazikika kosungira.
Kapangidwe ka filimu yophimba, yoletsa kuphulika, kupanga filimu, komanso yoletsa kugwa kwa denga zimadalira kulemera kwa mamolekyu aHECHEC ndi ma polima ena osagwirizana ndi madzi omwe amasungunuka m'madzi amalimbitsa gawo lamadzi la chophimbacho. Zothina za cellulose zitha kugwiritsidwa ntchito zokha kapena kuphatikiza ndi zothina zina kuti mupeze rheology yapadera. Ma ether a cellulose amatha kukhala ndi kulemera kosiyanasiyana kwa mamolekyulu ndi ma grade osiyanasiyana a viscosity, kuyambira yankho lochepa la 2% lamadzi lolemera ndi viscosity ya pafupifupi 10 mP s mpaka kukhuthala kwakukulu kwa mamolekyulu a 100 000 mP s. Ma grade otsika a molekyulu nthawi zambiri amagwiritsidwa ntchito ngati ma colloids oteteza mu polymerization ya latex paint emulsion, ndipo ma grade omwe amagwiritsidwa ntchito kwambiri (viscosity 4 800–50 000 mP·s) amagwiritsidwa ntchito ngati zothina. Kachitidwe ka mtundu uwu wa thickener ndi chifukwa cha kuchuluka kwa hydrogen bonds ndi kusakanikirana pakati pa unyolo wa mamolekyulu.
Celulose yachikhalidwe ndi polima wolemera kwambiri wa mamolekyulu womwe umakhuthala makamaka kudzera mu kutsekeka pakati pa unyolo wa mamolekyulu. Chifukwa cha kukhuthala kwakukulu pamlingo wotsika wa shear, mphamvu yolinganiza ndi yotsika, ndipo imakhudza kuwala kwa filimu yophimba. Pamlingo wapamwamba wa shear, kukhuthala ndi kotsika, kukana kwa splash kwa filimu yophimba ndi kotsika, ndipo kudzaza kwa filimu yophimba sikwabwino. Makhalidwe ogwiritsira ntchito a HEC, monga kukana burashi, kujambula ndi kufalikira kwa roller, amagwirizana mwachindunji ndi kusankha kwa thickener. Komanso makhalidwe ake oyenda monga kukhuthala ndi kukana kwa sag amakhudzidwa kwambiri ndi thickeners.
Cellulose yosinthidwa ndi hydrophobically (HMHEC) ndi chinthu chokhuthala cha cellulose chomwe chimasinthidwa ndi hydrophobic pa unyolo wina wa nthambi (magulu angapo a alkyl a unyolo wautali amalowetsedwa pa unyolo waukulu wa kapangidwe kake). Chophimbachi chili ndi kukhuthala kwakukulu pamitengo yodula kwambiri ndipo motero chimapangidwa bwino kwambiri. Monga Natrosol Plus Grade 330, 331, Cellosize SG-100, Bermocoll EHM-100. Mphamvu yake yokhuthala imafanana ndi ya cellulose ether thickeners yokhala ndi molekyulu yayikulu kwambiri. Imawongolera kukhuthala ndi kusinthasintha kwa ICI, ndikuchepetsa kupsinjika kwa pamwamba. Mwachitsanzo, kupsinjika kwa pamwamba pa HEC ndi pafupifupi 67 mN/m, ndipo kupsinjika kwa pamwamba pa HMHEC ndi 55~65 mN/m.
HMHEC ili ndi mphamvu yabwino kwambiri yopopera, yoletsa kugwa, yoletsa kusinthasintha, yowala bwino komanso yoletsa utoto. Imagwiritsidwa ntchito kwambiri ndipo ilibe zotsatira zoyipa pakupanga filimu ya utoto wa latex wa tinthu tating'onoting'ono tating'onoting'ono. Imagwira ntchito bwino popanga filimu komanso yoletsa dzimbiri. Chokhuthala ichi chimagwira ntchito bwino ndi makina a vinyl acetate copolymer ndipo chili ndi mphamvu zofanana ndi zokhuthala zina zosakanikirana, koma ndi njira zosavuta zopangira.
Nthawi yotumizira: Epulo-25-2024