Cov xim zas yog ib qho organic compound, feem ntau nyob rau hauv qhov muaj cov kua dej kom ua tiav cov tshuaj tiv thaiv, yog li lub ntiaj teb thawj cov xim zas hluavtaws yog thawj zaug muag hauv daim ntawv kua, ntawm chav kawm, qhov zoo ntawm cov xim zas thawj nrog rau qhov piv tam sim no yog deb ntawm, tsuas yog suav tias yog daim ntawv thawj ntawm cov kua zas niaj hnub no. Lub sijhawm ntawd, kwv yees li 20% ntawm cov khoom lag luam yog kua, thiab cov kua zas no feem ntau yog VAT dyes thiab mordant dyes.

Xyoo 1923, cov neeg Askiv tau ntxiv cov khoom ntxiv rau cov xim qub thiab tom qab sib tsoo, ua rau cov xim tsis yaj hauv cov dej sib xyaw. Los ntawm xyoo 1910, feem ntau cov xim tau raug tshem tawm thiab ua tiav rau hauv cov hmoov zoo ntawm qee qhov loj me.

Raws li xyoo 1924 cov ntaub ntawv, thaum lub sijhawm ntawd kwv yees li 80% ntawm cov xim ua cov hmoov zoo, VAT dyes tau ua rau ntau yam khoom me me, los ntawm cov khoom zoo heev mus rau 50um hmoov xim khoom. Tab sis cov xim hmoov qub muaj qhov tsis zoo ntawm cov hmoov av loj thiab tsis ntub dej.

Tom qab xyoo 1930, cov xim sib xyaw ua ke tau tsim ntxiv, tab sis tseem muaj qee qhov tsis zoo xws li yooj yim los nag thiab tsis ruaj khov cia.

Tam sim no cov kua zas tom qab ua tiav cov mis ua tiav ntawm ntau yam khoom tau zoo dua qub, lub sijhawm khaws cia tuaj yeem ncav cuag ntau dua ib nrab xyoo yam tsis muaj kev puas tsuaj, cov nqi ua kua zas qis, yooj yim siv thiab tau tsim kho tas li.

Txij li xyoo 1950, kev tshwm sim ntawm lub tshuab xuab zeb tau txhawb nqa kev txhim kho cov thev naus laus zis tom qab kho. Kev sib tsoo ntub nrog lub tshuab xuab zeb tuaj yeem tau txais cov khoom me me thiab nqaim dua. Tsis tas li ntawd, cov mis ua tiav tau txhim kho kom cov khoom yooj yim ntawm cov xim tuaj yeem ncav cuag li 1um, thiab qhov zoo ntawm cov khoom tsim los ntawm cov txheej txheem tshiab thiab cov khoom siv tau txhim kho zoo heev, thiab kev ua cov xim tsis yaj tau ua tiav zoo heev.

Nrog rau kev nce qib ntawm cov tshuab tshuaj lom neeg thiab cov khoom siv tshuaj, cov xim granular pib tshwm sim. Cov xim granular pom tseeb ntawm 100 ~ 300 um, muaj cov khoom khoob kuj muaj cov khoom khov, cov kua dej zoo dua li cov xim hmoov, ntub dej, tawg, thiab kov yeej qhov tsis zoo ntawm cov hmoov xim hmoov ntab saum ntuj, cov ntawv tshuaj tau tshwm sim tam sim ntawd tau txais tos los ntawm lub chaw haujlwm tsim khoom thiab daim ntawv thov, tam sim no ntau cov xim tau ua tiav rau hauv cov khoom granular.