Cov khoom ntawm hydroxypropyl methylcellulose

Hydroxypropyl methylcellulose yog ib hom non-ionic cellulose tov ether. Tsis zoo li ionic methyl carboxymethyl cellulose sib xyaw ether, nws tsis hnov ​​​​mob nrog cov hlau hnyav. Vim muaj qhov sib txawv ntawm cov ntsiab lus methoxyl thiab hydroxypropyl cov ntsiab lus hauv hydroxypropyl methylcellulose thiab cov viscosities sib txawv, muaj ntau ntau yam nrog cov khoom sib txawv, piv txwv li, cov ntsiab lus methoxyl siab thiab cov ntsiab lus tsis tshua muaj hydroxypropyl Nws qhov kev ua tau zoo yog ze rau ntawm methyl cellulose, thaum uas qis. methoxyl cov ntsiab lus thiab cov ntsiab lus siab hydroxypropyl yog ze rau ntawm hydroxypropyl methyl cellulose. Txawm li cas los xij, nyob rau hauv txhua yam, txawm hais tias tsuas yog ib qho me me ntawm pawg hydroxypropyl lossis ib qho me me ntawm pawg methoxyl, muaj qhov sib txawv loj hauv kev solubility hauv cov kuab tshuaj organic lossis flocculation kub hauv cov tshuaj aqueous.

(1) Solubility khoom ntawm hydroxypropyl methylcellulose
① Solubility ntawm hydroxypropyl methylcellulose hauv dej Hydroxypropyl methylcellulose yog ib hom methylcellulose hloov los ntawm propylene oxide (methoxypropylene), yog li nws tseem muaj cov khoom zoo ib yam li methyl cellulose Cellulose muaj cov yam ntxwv zoo sib xws ntawm cov dej txias solubility thiab dej kub insolubility. Txawm li cas los xij, vim yog hloov kho hydroxypropyl pawg, nws qhov kub thiab txias hauv dej kub yog siab dua li ntawm methyl cellulose. Piv txwv li, viscosity ntawm hydroxypropyl methylcellulose aqueous tov nrog 2% methoxy cov ntsiab lus hloov pauv qib DS = 0.73 thiab hydroxypropyl cov ntsiab lus MS = 0.46 yog 500 mpa·s ntawm 20 ° C, thiab nws cov gel kub Nws tuaj yeem ncav cuag ze li 100 ° C, thaum methyl cellulose ntawm tib qhov kub thiab txias tsuas yog li 55 ° C. Raws li rau nws solubility hauv dej, nws kuj tau zoo heev. Piv txwv li, pulverized hydroxypropyl methylcellulose (granular puab 0.2 ~ 0.5mm ntawm 20 ° C nrog 4% aqueous tov viscosity ntawm 2pa•s tuaj yeem muas ntawm chav tsev kub, nws yooj yim soluble hauv dej tsis txias.

② Solubility ntawm hydroxypropyl methylcellulose hauv cov kuab tshuaj organic Lub solubility ntawm hydroxypropyl methylcellulose hauv cov kuab tshuaj organic kuj zoo dua li ntawm methylcellulose. Rau cov khoom saum toj no 2.1, high-viscosity hydroxypropyl methylcellulose muaj hydroxypropyl MS = 1.5 ~ 1.8 thiab methoxy DS = 0.2 ~ 1.0, nrog rau tag nrho cov kev hloov pauv saum toj no 1.8, yog soluble hauv anhydrous methanol thiab ethanol daws nruab nrab, thiab thermoplastic thiab dej-soluble. . Nws kuj yog soluble hauv chlorinated hydrocarbons xws li methylene chloride thiab chloroform, thiab cov organic solvents xws li acetone, isopropanol thiab diacetone cawv. Nws solubility hauv cov kuab tshuaj organic zoo dua li dej solubility.

(2) Cov yam ntxwv cuam tshuam rau viscosity ntawm hydroxypropyl methylcellulose Tus qauv viscosity kev txiav txim siab ntawm hydroxypropyl methylcellulose yog tib yam li lwm cov cellulose ethers, thiab ntsuas ntawm 20 ° C nrog 2% aqueous tov raws li tus qauv. Lub viscosity ntawm tib cov khoom nce nrog qhov nce ntawm cov concentration. Rau cov khoom uas muaj qhov sib txawv molecular hnyav ntawm tib qhov concentration, cov khoom uas muaj qhov hnyav dua molecular muaj viscosity ntau dua. Nws txoj kev sib raug zoo nrog kub yog zoo ib yam li cov methyl cellulose. Thaum kub nce, viscosity pib txo, tab sis thaum nws nce mus txog qhov kub thiab txias, qhov viscosity dheev nce thiab gelation tshwm sim. Lub gel kub ntawm cov khoom uas tsis muaj viscosity yog siab dua. yog siab. Nws cov ntsiab lus gel tsis yog tsuas yog cuam tshuam nrog viscosity ntawm ether, tab sis kuj muaj feem xyuam rau qhov sib piv ntawm methoxyl pawg thiab hydroxypropyl pawg hauv ether thiab qhov loj ntawm tag nrho cov kev hloov pauv. Nws yuav tsum tau muab sau tseg tias hydroxypropyl methylcellulose kuj yog pseudoplastic, thiab nws cov tshuaj yog ruaj khov nyob rau hauv chav tsev kub yam tsis muaj degradation nyob rau hauv viscosity tsuas yog muaj peev xwm ntawm enzymatic degradation.

(3) Cov ntsev kam rau ntawm hydroxypropyl methylcellulose Txij li hydroxypropyl methylcellulose yog ib qho uas tsis yog-ionic ether, nws tsis ionize hauv dej, tsis zoo li lwm cov ionic cellulose ethers, Piv txwv li, carboxymethyl cellulose reacts nrog hnyav hlau ions thiab precipitates tawm hauv cov tshuaj. Cov ntsev dav dav xws li chloride, bromide, phosphate, nitrate, thiab lwm yam yuav tsis ua kom dej nag thaum ntxiv rau nws cov tshuaj aqueous. Txawm li cas los xij, qhov sib ntxiv ntawm ntsev muaj qee qhov cuam tshuam rau qhov kub ntawm flocculation ntawm nws cov kua dej aqueous. Thaum cov ntsev concentration nce, lub gel kub txo. Thaum cov ntsev concentration qis dua qhov taw tes flocculation, viscosity ntawm cov tshuaj yuav nce ntxiv. Yog li ntawd, ib co ntsev ntxiv. , hauv daim ntawv thov, nws tuaj yeem ua tiav cov nyhuv thickening ntau dua kev lag luam. Yog li ntawd, hauv qee daim ntawv thov, nws yog qhov zoo dua los siv cov khoom sib xyaw ntawm cellulose ether thiab ntsev ntau dua li cov tshuaj ether ntau dua kom ua tiav cov nyhuv thickening.

(4) Hydroxypropyl methylcellulose acid thiab alkali tsis kam Hydroxypropyl methylcellulose feem ntau ruaj khov rau cov kua qaub thiab alkalis, thiab tsis cuam tshuam rau thaj tsam ntawm pH 2 ~ 12. Nws tuaj yeem tiv taus qee yam ntawm cov kua qaub, xws li formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, thiab lwm yam. Tab sis cov concentrated acid muaj cov nyhuv ntawm kev txo cov viscosity. Alkalis xws li caustic soda, caustic potash thiab txiv qaub dej tsis muaj kev cuam tshuam rau nws, tab sis lawv tuaj yeem ua rau me ntsis viscosity ntawm cov tshuaj, thiab maj mam txo nws.

(5) Kev sib xyaw ua ke ntawm hydroxypropyl methylcellulose Hydroxypropyl methylcellulose tov tuaj yeem tov nrog dej-soluble polymer tebchaw los tsim ib qho kev daws teeb meem thiab pob tshab nrog ntau dua viscosity. Cov khoom siv polymer no suav nrog polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinylsiloxane, hydroxyethyl cellulose, thiab methyl cellulose. Ntuj siab molecular tebchaw xws li cov pos hniav arabic, locust taum gum, karaya gum, thiab lwm yam kuj muaj zoo compatibility nrog nws cov tshuaj. Hydroxypropyl methylcellulose kuj tuaj yeem tov nrog mannitol ester lossis sorbitol ester ntawm stearic acid lossis palmitic acid, thiab tseem tuaj yeem tov nrog glycerin, sorbitol thiab mannitol, thiab cov tshuaj no tuaj yeem siv los ua hydroxypropyl methylcellulose Plasticizer rau cellulose.

(6) Insoluble dej-soluble cellulose ethers ntawm hydroxypropyl methylcellulose tuaj yeem nqa tawm qhov sib txuas nrog aldehydes, kom cov dej-soluble ethers no precipitated hauv cov tshuaj thiab ua insoluble hauv dej. Cov aldehydes uas ua rau hydroxypropyl methylcellulose insoluble muaj xws li formaldehyde, glyoxal, succinic aldehyde, adipaldehyde, thiab lwm yam. Thaum siv formaldehyde, tshwj xeeb yuav tsum tau them rau tus nqi pH ntawm cov tshuaj, ntawm cov glyoxal reacts sai, yog li glyoxal feem ntau siv raws li ib tug crosslinking. tus neeg sawv cev hauv industrial ntau lawm. Tus nqi ntawm qhov sib txuas ntawm tus neeg sawv cev hauv cov tshuaj no yog 0.2% ~ 10% ntawm qhov loj ntawm ether, nyiam dua 7% ~ 10%, piv txwv li, 3.3% ~ 6% ntawm glyoxal yog qhov tsim nyog tshaj. Feem ntau, kev kho mob kub yog 0 ~ 30 ℃, thiab lub sij hawm yog 1 ~ 120min. Cov tshuaj tiv thaiv kev sib txuas yuav tsum tau ua nyob rau hauv acidic tej yam kev mob. Feem ntau, cov tshuaj yog thawj zaug ntxiv nrog inorganic muaj zog acid lossis organic carboxylic acid los kho cov pH ntawm cov tshuaj mus txog 2 ~ 6, nyiam dua ntawm 4 ~ 6, thiab tom qab ntawd ntxiv aldehydes los ua cov tshuaj tiv thaiv kev sib txuas. Cov kua qaub uas siv tau muaj hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxyacetic acid, succinic acid los yog citric acid thiab lwm yam, nyob rau hauv uas nrog formic acid los yog acetic acid yog advisable, thiab formic acid yog pom zoo. Cov kua qaub thiab aldehyde kuj tseem tuaj yeem ntxiv ib txhij kom tso cai rau kev daws kom muaj kev sib txuas sib txuas hauv qhov xav tau pH ntau. Cov tshuaj tiv thaiv no feem ntau siv rau hauv cov txheej txheem kho zaum kawg hauv kev npaj cov txheej txheem ntawm cellulose ethers. Tom qab cov cellulose ether yog insoluble, nws yooj yim siv

20 ~ 25 ℃ dej rau ntxuav thiab purification. Thaum cov khoom siv, cov tshuaj alkaline tuaj yeem muab ntxiv rau hauv cov tshuaj ntawm cov khoom los kho cov pH ntawm cov tshuaj kom alkaline, thiab cov khoom yuav yaj hauv cov tshuaj sai sai. Txoj kev no kuj tseem siv tau rau kev kho cov yeeb yaj kiab tom qab cov tshuaj cellulose ether tau ua rau hauv cov yeeb yaj kiab kom nws ua ib zaj duab xis insoluble.

(7) Enzyme kuj ntawm hydroxypropyl methylcellulose Nyob rau hauv txoj kev tshawb xav, cellulose derivatives, xws li ib tug ruaj khov sib koom pab pawg neeg ntawm txhua pab pawg neeg anhydroglucose, yuav tsis raug rau microbial yaig, tab sis qhov tseeb, thaum hloov nqi ntawm cov khoom tiav lawm ntau tshaj 1, nws yuav. kuj yuav degraded los ntawm enzymes, uas txhais tau hais tias cov degree ntawm kev hloov ntawm txhua pab pawg neeg ntawm cov cellulose saw yog tsis. uniform txaus, thiab cov kab mob tuaj yeem erode ntawm unsubstituted anhydroglucose pawg. Qab Zib yog tsim thiab absorbed ua cov as-ham rau cov kab mob. Yog li, yog tias qib ntawm etherification hloov pauv ntawm cellulose nce, qhov kev tiv thaiv rau enzymatic yaig ntawm cellulose ether kuj yuav nce. Raws li cov lus ceeb toom, nyob rau hauv kev tswj hwm, cov txiaj ntsig ntawm hydrolysis ntawm cov enzymes, qhov seem viscosity ntawm hydroxypropyl methylcellulose (DS = 1.9) yog 13.2%, methylcellulose (DS = 1.83) yog 7.3%, methylcellulose (DS = 1.66) yog 3.8%, thiab hydroxyethyl cellulose yog 1.7%. Nws tuaj yeem pom tias hydroxypropyl methylcellulose muaj peev xwm tiv thaiv enzyme. Yog li ntawd, qhov zoo heev enzyme kuj ntawm hydroxypropyl methylcellulose, ua ke nrog nws zoo dispersibility, thickening thiab film-forming zog, yog siv nyob rau hauv dej-emulsion txheej, thiab lwm yam, thiab feem ntau tsis tas yuav ntxiv preservatives. Txawm li cas los xij, rau kev khaws cia ntev ntev ntawm kev daws teeb meem lossis tuaj yeem kis tau los ntawm sab nraud, cov tshuaj tua kab mob tuaj yeem raug ntxiv raws li kev ceev faj, thiab kev xaiv tuaj yeem txiav txim siab raws li qhov xav tau kawg ntawm kev daws. Phenylmercuric acetate thiab manganese fluorosilicate yog cov tshuaj tiv thaiv zoo, tab sis lawv txhua tus muaj Toxicity, yuav tsum tau them nyiaj rau kev ua haujlwm. Feem ntau, 1 ~ 5mg ntawm phenylmercury acetate tuaj yeem muab ntxiv rau cov tshuaj ib liter ntawm cov tshuaj.

(8) Kev ua tau zoo ntawm hydroxypropyl methylcellulose zaj duab xis Hydroxypropyl methylcellulose muaj cov yeeb yaj kiab zoo heev. Nws cov tshuaj aqueous lossis cov kuab tshuaj organic yog coated rau ntawm iav phaj, thiab nws yuav dawb tom qab ziab. Xim, pob tshab thiab tawv zaj duab xis. Nws muaj cov dej noo zoo thiab tseem ruaj khov ntawm qhov kub thiab txias. Yog hais tias hygroscopic plasticizer ntxiv, nws elongation thiab yooj tuaj yeem txhim kho. Nyob rau hauv cov nqe lus ntawm kev txhim kho yooj, plasticizers xws li glycerin thiab sorbitol yog qhov tsim nyog tshaj plaws. Feem ntau, cov tshuaj concentration yog 2% ~ 3%, thiab cov yas yas yog 10% ~ 20% ntawm cellulose ether. Yog tias cov ntsiab lus ntawm plasticizer siab dhau lawm, colloidal dehydration shrinkage yuav tshwm sim ntawm cov av noo siab. Lub zog tensile ntawm zaj duab xis nrog plasticizer ntxiv yog qhov loj dua qhov uas tsis muaj plasticizer, thiab nws nce nrog qhov nce ntawm cov nyiaj ntxiv. Raws li rau hygroscopicity ntawm zaj duab xis, nws kuj nce nrog qhov nce ntawm cov nyiaj ntawm plasticizer.