Hydroxypropyl methylcellulose (HPMC) yog ib nrab - khoom siv hluavtaws uas muaj qhov hnyav ntawm 10,000 txog 1,500,000. Nws tuaj yeem npaj tau los ntawm ob txoj hauv kev: (1) kho cov paj rwb lint lossis ntoo pulp fibers nrog caustic soda, ua raws li cov tshuaj tiv thaiv nrog chloromethane thiab propylene oxide, thiab tom qab ntawd ua kom zoo dua thiab pulverizing; (2) kho cov qib methylcellulose uas haum nrog sodium hydroxide, reacting nrog propylene oxide ntawm qhov kub thiab txias mus rau qhov xav tau degree, thiab tom qab ntawd ua kom zoo dua.
Cov paj rwb refined cellulose yog kho nrog alkali tov ntawm 35-40℃rau ib nrab ib teev, nias, pulverized, thiab hnub nyoog tsim nyog ntawm 35℃los xyuas kom meej qhov nruab nrab℃ntawm polymerization ntawm lub resulting alkali cellulose nyob rau hauv qhov yuav tsum tau ntau yam. Tom qab ntawd cov alkali cellulose yog muab tso rau hauv ib lub reactor etherification, nrog propylene oxide thiab chloromethane ntxiv sequentially, thiab etherified ntawm 50-80℃rau 5 teev, nrog rau siab tshaj plaws ntawm kwv yees li 1.8 MPa. Tom qab ntawd, qhov tsim nyog ntawm hydrochloric acid thiab oxalic acid ntxiv rau cov dej kub ntawm 90℃los ntxuav cov khoom, ua rau nws nthuav dav hauv ntim. Cov khoom siv lub cev qhuav dej siv lub centrifuge, ntxuav kom txog thaum nruab nrab, thiab qhuav nrog cua kub ntawm 130℃kom txog thaum cov dej noo qis dua 5%. Thaum kawg, nws yog pulverized thiab dhau los ntawm 20-mesh sieve kom tau txais cov khoom tiav.
