Cov khoom ntawm hydroxypropyl methylcellulose

Hydroxypropyl methylcellulose yog ib hom non-ionic cellulose mixed ether. Tsis zoo li ionic methyl carboxymethyl cellulose mixed ether, nws tsis cuam tshuam nrog cov hlau hnyav. Vim muaj qhov sib txawv ntawm cov ntsiab lus methoxyl thiab cov ntsiab lus hydroxypropyl hauv hydroxypropyl methylcellulose thiab viscosities sib txawv, muaj ntau hom nrog cov khoom sib txawv, piv txwv li, cov ntsiab lus methoxyl siab thiab cov ntsiab lus hydroxypropyl qis Nws cov kev ua tau zoo ze rau cov methyl cellulose, thaum cov ntsiab lus methoxyl qis thiab cov ntsiab lus hydroxypropyl siab ze rau cov hydroxypropyl methyl cellulose. Txawm li cas los xij, hauv txhua hom, txawm hais tias tsuas yog me me ntawm hydroxypropyl pawg lossis me me ntawm methoxyl pawg muaj, muaj qhov sib txawv loj hauv kev yaj hauv cov kuab tshuaj organic lossis qhov kub ntawm cov dej hauv cov kua dej.

(1) Cov khoom yaj ntawm hydroxypropyl methylcellulose
① Kev yaj ntawm hydroxypropyl methylcellulose hauv dej Hydroxypropyl methylcellulose yog ib hom methylcellulose hloov kho 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 kev yaj dej txias thiab kev yaj dej kub. Txawm li cas los xij, vim yog pawg hydroxypropyl hloov kho, nws qhov kub gelation hauv dej kub siab dua li ntawm methyl cellulose. Piv txwv li, qhov viscosity ntawm hydroxypropyl methylcellulose aqueous kua nrog 2% methoxy cov ntsiab lus hloov pauv degree DS = 0.73 thiab hydroxypropyl cov ntsiab lus MS = 0.46 yog 500 mpa · s ntawm 20 ° C, thiab nws qhov kub gel Nws tuaj yeem ncav cuag ze li ntawm 100 ° C, thaum methyl cellulose ntawm tib qhov kub tsuas yog li 55 ° C. Raws li rau nws cov solubility hauv dej, nws kuj tau txhim kho zoo heev. Piv txwv li, cov hydroxypropyl methylcellulose uas raug pulverized (cov duab granular 0.2 ~ 0.5 hli ntawm 20 ° C nrog 4% viscosity aqueous solution ntawm 2 pa • s tuaj yeem yuav tau ntawm Qhov kub thiab txias hauv chav tsev, nws yooj yim yaj hauv dej yam tsis tau txias.

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

(2) Cov yam ntxwv cuam tshuam rau qhov viscosity ntawm hydroxypropyl methylcellulose Qhov kev txiav txim siab viscosity txheem ntawm hydroxypropyl methylcellulose yog tib yam li lwm cov cellulose ethers, thiab ntsuas ntawm 20 ° C nrog 2% aqueous kua raws li tus qauv. Lub viscosity ntawm tib yam khoom nce nrog qhov nce ntawm qhov concentration. Rau cov khoom nrog cov qhov hnyav molecular sib txawv ntawm tib qhov concentration, cov khoom nrog lub qhov hnyav molecular loj dua muaj viscosity siab dua. Nws txoj kev sib raug zoo nrog qhov kub thiab txias zoo ib yam li methyl cellulose. Thaum qhov kub nce, lub viscosity pib txo qis, tab sis thaum nws mus txog qee qhov kub, lub viscosity tam sim ntawd nce thiab gelation tshwm sim. Lub gel kub ntawm cov khoom qis-viscosity siab dua. yog siab. Nws cov gel taw tes tsis yog tsuas yog cuam tshuam nrog viscosity ntawm ether, tab sis kuj cuam tshuam nrog qhov sib piv ntawm methoxyl pawg thiab hydroxypropyl pawg hauv ether thiab qhov loj ntawm tag nrho cov degree hloov pauv. Nws yuav tsum tau sau tseg tias hydroxypropyl methylcellulose kuj yog pseudoplastic, thiab nws cov kua ruaj khov ntawm chav tsev kub yam tsis muaj kev puas tsuaj hauv viscosity tsuas yog qhov ua tau ntawm enzymatic degradation.

(3) Kev kam rau ntsev ntawm hydroxypropyl methylcellulose Vim tias hydroxypropyl methylcellulose yog cov ether tsis-ionic, nws tsis ionize hauv dej media, tsis zoo li lwm cov ionic cellulose ethers, Piv txwv li, carboxymethyl cellulose reacts nrog cov hlau hnyav ions thiab precipitates tawm hauv cov kua. Cov ntsev dav dav xws li chloride, bromide, phosphate, nitrate, thiab lwm yam yuav tsis precipitate thaum ntxiv rau nws cov kua aqueous. Txawm li cas los xij, qhov ntxiv ntsev muaj qee qhov cuam tshuam rau qhov kub flocculation ntawm nws cov kua aqueous. Thaum cov ntsev concentration nce, qhov kub gel txo qis. Thaum cov ntsev concentration qis dua qhov flocculation point, qhov viscosity ntawm cov kua feem ntau nce. Yog li ntawd, ib qho ntau ntawm ntsev ntxiv. , hauv daim ntawv thov, nws tuaj yeem ua tiav cov nyhuv thickening ntau dua kev lag luam. Yog li ntawd, hauv qee qhov kev siv, nws yog qhov zoo dua los siv cov khoom sib xyaw ntawm cellulose ether thiab ntsev dua li qhov concentration siab dua ntawm ether kua 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 pH 2 ~ 12. Nws tuaj yeem tiv taus qee qhov ntawm cov kua qaub teeb, xws li formic acid, acetic acid, citric acid, succinic acid, phosphoric acid, boric acid, thiab lwm yam. Tab sis cov kua qaub concentrated muaj cov nyhuv ntawm kev txo cov viscosity. Cov alkalis xws li caustic soda, caustic potash thiab cov dej txiv qaub tsis muaj cov nyhuv rau nws, tab sis lawv tuaj yeem ua rau me ntsis nce qhov viscosity ntawm cov tshuaj, thiab tom qab ntawd maj mam txo nws.

(5) Kev sib haum xeeb ntawm hydroxypropyl methylcellulose Hydroxypropyl methylcellulose kua tuaj yeem sib xyaw nrog cov tshuaj polymer uas yaj tau hauv dej los ua cov tshuaj sib xws thiab pob tshab nrog viscosity siab dua. Cov tshuaj polymer no suav nrog polyethylene glycol, polyvinyl acetate, polysilicone, polymethylvinylsiloxane, hydroxyethyl cellulose, thiab methyl cellulose. Cov tshuaj molecular siab ntuj xws li gum arabic, locust bean gum, karaya gum, thiab lwm yam kuj muaj kev sib haum xeeb zoo nrog nws cov kua. Hydroxypropyl methylcellulose kuj tuaj yeem sib xyaw nrog mannitol ester lossis sorbitol ester ntawm stearic acid lossis palmitic acid, thiab kuj tuaj yeem sib xyaw nrog glycerin, sorbitol thiab mannitol, thiab cov tshuaj no tuaj yeem siv ua hydroxypropyl methylcellulose Plasticizer rau cellulose.

(6) Cov cellulose ethers uas tsis yaj hauv dej ntawm hydroxypropyl methylcellulose tuaj yeem ua rau muaj kev sib txuas ntawm cov aldehydes, yog li cov ethers uas yaj hauv dej no tau precipitated hauv cov tshuaj thiab ua rau tsis yaj hauv dej. Cov aldehydes uas ua rau hydroxypropyl methylcellulose tsis yaj suav nrog formaldehyde, glyoxal, succinic aldehyde, adipaldehyde, thiab lwm yam. Thaum siv formaldehyde, yuav tsum tau them rau tus nqi pH ntawm cov tshuaj, ntawm cov uas glyoxal teb sai dua, yog li glyoxal feem ntau siv ua tus neeg sawv cev sib txuas hauv kev tsim khoom lag luam. Tus nqi ntawm hom neeg sawv cev sib txuas no hauv cov tshuaj yog 0.2% ~ 10% ntawm qhov hnyav ntawm ether, zoo dua 7% ~ 10%, piv txwv li, 3.3% ~ 6% ntawm glyoxal yog qhov tsim nyog tshaj plaws. Feem ntau, qhov kub thiab txias kho yog 0 ~ 30 ℃, thiab lub sijhawm yog 1 ~ 120 feeb. Kev sib txuas ntawm kev sib txuas yuav tsum tau ua nyob rau hauv cov xwm txheej acidic. Feem ntau, cov tshuaj no yog ntxiv ua ntej nrog cov kua qaub inorganic lossis cov kua qaub organic carboxylic los kho qhov pH ntawm cov tshuaj kom txog li 2 ~ 6, zoo dua ntawm 4 ~ 6, thiab tom qab ntawd ntxiv cov aldehydes los ua qhov kev sib txuas lus. Cov kua qaub siv muaj hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, hydroxyacetic acid, succinic acid lossis citric acid thiab lwm yam, qhov twg nrog formic acid lossis acetic acid yog qhov zoo tshaj plaws, thiab formic acid yog qhov zoo tshaj plaws. Cov kua qaub thiab aldehyde kuj tseem tuaj yeem ntxiv tib lub sijhawm kom tso cai rau cov tshuaj kom dhau los ua qhov kev sib txuas lus hauv pH ntau yam. Cov tshuaj no feem ntau siv rau hauv cov txheej txheem kho mob kawg hauv cov txheej txheem npaj ntawm cellulose ethers. Tom qab cellulose ether tsis yaj, nws yooj yim siv.

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

(7) Kev tsis kam ntawm enzyme ntawm hydroxypropyl methylcellulose Hauv kev xav, cellulose derivatives, xws li ib pawg neeg hloov pauv ruaj khov ntawm txhua pawg anhydroglucose, tsis yooj yim rau kev puas tsuaj ntawm cov kab mob me me, tab sis qhov tseeb, thaum tus nqi hloov pauv ntawm cov khoom tiav tshaj 1, nws kuj yuav raug rhuav tshem los ntawm cov enzymes, uas txhais tau tias qib ntawm kev hloov pauv ntawm txhua pawg ntawm cov saw hlau cellulose tsis sib xws txaus, thiab cov kab mob me me tuaj yeem tawg ntawm pawg anhydroglucose tsis tau hloov pauv. Cov suab thaj tau tsim thiab nqus tau ua cov as-ham rau cov kab mob me me. Yog li ntawd, yog tias qib ntawm kev hloov pauv etherification ntawm cellulose nce ntxiv, qhov kev tiv thaiv rau kev puas tsuaj ntawm enzymatic ntawm cellulose ether kuj tseem yuav nce ntxiv. Raws li cov ntawv ceeb toom, nyob rau hauv cov xwm txheej tswj hwm, cov txiaj ntsig 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 zoo heev. Yog li ntawd, qhov kev tiv thaiv enzyme zoo heev ntawm hydroxypropyl methylcellulose, ua ke nrog nws cov khoom tawg zoo, thickening thiab zaj duab xis-tsim cov khoom, yog siv rau hauv dej-emulsion coatings, thiab lwm yam, thiab feem ntau tsis tas yuav ntxiv cov tshuaj preservatives. Txawm li cas los xij, rau kev khaws cia ntev ntawm cov tshuaj lossis ua rau muaj kev sib kis los ntawm sab nraud, cov tshuaj preservatives tuaj yeem ntxiv ua kev ceev faj, thiab kev xaiv tuaj yeem txiav txim siab raws li qhov yuav tsum tau ua tiav ntawm cov tshuaj. Phenylmercuric acetate thiab manganese fluorosilicate yog cov tshuaj preservatives zoo, tab sis lawv txhua tus muaj Toxicity, yuav tsum tau them sai sai rau kev ua haujlwm. Feem ntau, 1 ~ 5mg ntawm phenylmercury acetate tuaj yeem ntxiv rau cov tshuaj ib liter ntawm cov tshuaj.

(8) Kev ua tau zoo ntawm hydroxypropyl methylcellulose zaj duab xis Hydroxypropyl methylcellulose muaj cov khoom zoo heev rau kev tsim zaj duab xis. Nws cov kua dej lossis cov organic solvent kua yog coated rau ntawm lub phaj iav, thiab nws ua dawb tom qab ziab. Xim, pob tshab thiab tawv zaj duab xis. Nws muaj kev tiv thaiv dej noo zoo thiab tseem khov kho ntawm qhov kub siab. Yog tias ntxiv hygroscopic plasticizer, nws cov elongation thiab kev ywj pheej tuaj yeem txhim kho. Hauv kev txhim kho kev ywj pheej, cov plasticizers xws li glycerin thiab sorbitol yog qhov tsim nyog tshaj plaws. Feem ntau, qhov concentration ntawm cov tshuaj yog 2% ~ 3%, thiab qhov ntau ntawm plasticizer yog 10% ~ 20% ntawm cellulose ether. Yog tias cov ntsiab lus ntawm plasticizer siab dhau, colloidal dehydration shrinkage yuav tshwm sim ntawm qhov siab noo noo. Lub zog tensile ntawm zaj duab xis nrog plasticizer ntxiv yog loj dua li qhov tsis muaj plasticizer, thiab nws nce nrog qhov nce ntawm qhov ntxiv. Raws li rau hygroscopicity ntawm zaj duab xis, nws kuj nce nrog qhov nce ntawm qhov ntau ntawm plasticizer.