Cellulose yog ib hom polysaccharide uas tsim ntau yam ethers uas yaj tau hauv dej. Cellulose thickeners yog cov polymers uas yaj tau hauv dej uas tsis yog ionic. Nws keeb kwm siv ntev heev, ntau tshaj 30 xyoo, thiab muaj ntau yam. Lawv tseem siv rau hauv yuav luag txhua cov xim latex thiab yog cov thickeners tseem ceeb. Cellulosic thickeners muaj txiaj ntsig zoo heev hauv cov kab ke dej vim tias lawv ua rau cov dej tuab. Hauv kev lag luam xim, cov cellulose thickeners feem ntau siv yog:methyl cellulose (MC), Hydroxyethyl Cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), hydroxypropyl cellulose (HPC),Hydroxypropyl methyl cellulose (HPMC)thiab hydrophobically hloov kho hydroxyethyl cellulose (HMHEC). HEC yog ib qho polysaccharide uas yaj tau hauv dej uas siv dav hauv kev ua kom tuab ntawm cov xim pleev xim matt thiab semi-gloss. Cov thickeners muaj nyob rau hauv ntau qib viscosity thiab cov thickeners nrog cov cellulose no muaj kev sib xws xim zoo heev thiab kev ruaj khov cia.
Cov khoom siv leveling, anti-splash, zaj duab xis-tsim thiab anti-sagging ntawm cov zaj duab xis txheej nyob ntawm qhov hnyav molecular ntawmHEC. HEC thiab lwm yam polymers uas tsis sib txuas nrog dej ua rau cov dej ntawm cov txheej tuab. Cellulose thickeners siv tau ib leeg lossis ua ke nrog lwm cov thickeners kom tau txais rheology tshwj xeeb. Cellulose ethers tuaj yeem muaj qhov hnyav molecular sib txawv thiab cov qib viscosity sib txawv, xws li qhov hnyav molecular qis 2% aqueous kua nrog viscosity ntawm kwv yees li 10 mP s mus rau qhov hnyav molecular siab viscosity ntawm 100 000 mP s. Cov qib molecular qis feem ntau yog siv los ua cov colloids tiv thaiv hauv cov xim latex emulsion polymerization, thiab feem ntau siv cov qib (viscosity 4 800–50 000 mP · s) yog siv los ua cov thickeners. Lub tshuab ntawm hom thickener no yog vim muaj cov dej noo ntau ntawm cov hydrogen bonds thiab kev sib koom ua ke ntawm cov saw hlau molecular.
Cov cellulose ib txwm muaj yog ib qho polymer hnyav molecular siab uas tuab feem ntau los ntawm kev sib txuas ntawm cov saw hlau molecular. Vim yog qhov viscosity siab ntawm qhov nrawm qis, qhov khoom leveling tsis zoo, thiab nws cuam tshuam rau qhov ci ntawm cov zaj duab xis txheej. Ntawm qhov nrawm siab, qhov viscosity qis, qhov tsis kam ntawm cov zaj duab xis txheej tsis zoo, thiab qhov puv ntawm cov zaj duab xis txheej tsis zoo. Cov yam ntxwv ntawm daim ntawv thov ntawm HEC, xws li kev tsis kam ntawm txhuam, zaj duab xis thiab cov menyuam spatter, yog ncaj qha cuam tshuam rau kev xaiv cov thickener. Tsis tas li ntawd nws cov khoom ntws xws li leveling thiab sag tsis kam feem ntau cuam tshuam los ntawm cov thickeners.
Hydrophobically modified cellulose (HMHEC) yog ib qho cellulose thickener uas muaj hydrophobic modification ntawm qee cov saw branched (ob peb lub saw alkyl ntev tau qhia raws li cov saw tseem ceeb ntawm cov qauv). Cov txheej no muaj viscosity siab dua ntawm cov nqi shear siab thiab yog li ntawd zoo dua zaj duab xis tsim. Xws li Natrosol Plus Qib 330, 331, Cellosize SG-100, Bermocoll EHM-100. Nws cov nyhuv thickening yog sib piv rau cov cellulose ether thickeners nrog cov molecular loj dua. Nws txhim kho qhov viscosity thiab leveling ntawm ICI, thiab txo qhov nro ntawm qhov chaw. Piv txwv li, qhov nro ntawm qhov chaw ntawm HEC yog li 67 mN / m, thiab qhov nro ntawm qhov chaw ntawm HMHEC yog 55 ~ 65 mN / m.
HMHEC muaj kev txau zoo heev, tiv thaiv kev sagging, cov khoom sib npaug, zoo gloss thiab tiv thaiv cov xim caking. Nws yog siv dav thiab tsis muaj kev cuam tshuam tsis zoo rau kev tsim zaj duab xis ntawm cov xim latex me me. Kev ua tau zoo ntawm zaj duab xis thiab kev ua tau zoo tiv thaiv kev xeb. Cov khoom sib koom ua ke thickener no ua haujlwm zoo dua nrog cov kab ke vinyl acetate copolymer thiab muaj cov khoom zoo ib yam li lwm cov khoom sib koom ua ke thickeners, tab sis nrog cov qauv yooj yim dua.
Lub sijhawm tshaj tawm: Plaub Hlis-25-2024