1. Tsanangudzo uye basa re thickener
Zviwedzerwa zvinogona kuwedzera zvakanyanya viscosity yependi yemvura inonzi thickeners.
Thickeners inoita basa rakakosha mukugadzira, kuchengetedza uye kuvaka kwekupfeka.
Basa guru reiyo thickener ndeyekuwedzera viscosity yekuputira kuti isangane nezvinodiwa zvematanho akasiyana ekushandisa. Nekudaro, iyo viscosity inodikanwa nekupfeka pamatanho akasiyana akasiyana. Eg:
Munguva yekuchengetedza, zvinodikanwa kuva nepamusoro viscosity kudzivirira iyo pigment kubva pakugadzirisa;
Munguva yekuvaka, zvinodikanwa kuve neine mwero viscosity kuve nechokwadi chekuti pende ine yakanaka brushability pasina yakawandisa pendi stain;
Mushure mekuvaka, zvinotarisirwa kuti viscosity inogona kukurumidza kudzoka kune yakakwira viscosity mushure menguva pfupi lag (leveling process) kudzivirira sagging.
Iyo fluidity yemvura yakavharwa isiri yeNewtonian.
Kana iyo viscosity yepende inoderera nekuwedzera kweshear simba, inonzi pseudoplastic fluid, uye yakawanda yepende inonzi pseudoplastic fluid.
Kana mafambiro ekuyerera kwepseudoplastic fluid yakabatana nenhoroondo yayo, ndiko kuti, inoenderana nenguva, inonzi thixotropic fluid.
Paunenge uchigadzira machira, isu tinowanzo edza nekuchenjerera kuita machira ethixotropic, sekuwedzera zvinowedzera.
Kana iyo thixotropy yekuputira yakakodzera, inogona kugadzirisa kupesana kwematanho akasiyana-siyana ekuputira, uye inosangana nezvinodiwa zveunyanzvi zvekusiyana kweviscosity yekuputira mukuchengetedza, kugadzirisa kwekuvaka, uye kuomesa matanho.
Zvimwe zvinopisa zvinogona kupa pende nepamusoro thixotropy, kuitira kuti ive nepamusoro viscosity pakuzorora kana pane yakaderera shear rate (yakadai sekuchengetedza kana kutakura), kuitira kudzivirira pigment mupende kubva pakugadzirisa. Uye pasi pepamusoro shear rate (yakadai sekugadzira nzira), ine yakaderera viscosity, kuitira kuti kuvhara kuve nekuyerera kwakakwana uye kuenzana.
Thixotropy inomiririrwa nethixotropic index TI uye kuyerwa neBrookfield viscometer.
TI = viscosity (yakayerwa pa6r / min) / viscosity (yakayerwa pa60r / min)
2. Mhando dzema thickeners nemigumisiro yadzo pakugadzirisa zvinhu
(1) Mhando Panyaya yekuumbwa kwemakemikari, makobvu akakamurwa kuita mapoka maviri: organic uye inorganic.
Inorganic mhando dzinosanganisira bentonite, attapulgite, aluminium magnesium silicate, lithium magnesium silicate, nezvimwewo, organic mhando semethyl cellulose, hydroxyethyl cellulose, polyacrylate, polymethacrylate, acrylic acid kana methyl Acrylic homopolymer kana copolymer uye polyurethane etc.
Kubva pakuona kwekuita kweiyo rheological properties yejasi, thickeners yakakamurwa kuva thixotropic thickeners uye associative thickeners. Panyaya yezvinodiwa zvekushanda, huwandu hwehupfu hunofanirwa kuve hushoma uye kukora mhedzisiro yakanaka; hazvisi nyore kunyungudutswa nema enzymes; kana tembiricha kana pH kukosha kweiyo sisitimu ichichinja, viscosity yekupfeka haizodzikisirwe zvakanyanya, uye iyo pigment uye filler haizo flocculated. ; Kugadzikana kwakanaka kwekuchengetedza; kuchengetwa kwemvura kwakanaka, hapana chiitiko chinobuda furo uye hapana mhedzisiro yakaipa pakuita kwefirimu rekuputira.
① Cellulose thickener
Iwo ma cellulose thickeners anoshandiswa mukupotera anonyanya methylcellulose, hydroxyethylcellulose uye hydroxypropylmethylcellulose, uye maviri ekupedzisira anonyanya kushandiswa.
Hydroxyethyl cellulose chigadzirwa chinowanikwa nekutsiva mapoka ehydroxyl pazvikamu zveglucose zvechisikigo cellulose nemapoka ehydroxyethyl. Izvo zvinotsanangurwa uye mhando dzezvigadzirwa zvinonyanya kusiyaniswa zvinoenderana nedhigirii rekutsiva uye viscosity.
Iwo akasiyana ehydroxyethyl cellulose akakamurwawo kuita yakajairwa kunyungudika mhando, kukurumidza kupararira mhando uye biological kugadzikana mhando. Nezve nzira yekushandiswa ine chekuita, hydroxyethyl cellulose inogona kuwedzerwa pamatanho akasiyana mukuita kwekuputira. Mhando yekukurumidza-kuparadzira inogona kuwedzerwa zvakananga nenzira yehupfu yakaoma. Nekudaro, iyo pH kukosha kweiyo system isati yawedzera kunofanirwa kuve isingasviki 7, kunyanya nekuti hydroxyethyl cellulose inonyungudika zvishoma nezvishoma pane yakaderera pH kukosha, uye pane nguva yakakwana yekuti mvura ipinde mukati mezvimedu, uye ipapo iyo pH kukosha inowedzerwa kuti iite Inonyungudika nekukurumidza. Matanho anowirirana anogonawo kushandiswa kugadzirira imwe denderedzwa yeglue mhinduro uye kuiwedzera kune yekubikira system.
Hydroxypropyl methylcellulosechigadzirwa chinowanikwa nekutsiva iyo hydroxyl boka pane yeglucose unit ye natural cellulose neboka remethoxy, nepo chimwe chikamu chinotsiviwa neboka rehydroxypropyl. Iko kukora kwaro kwakangofanana neiyo yehydroxyethyl cellulose. Uye inopesana nekuora kwe enzymatic, asi kunyungudika kwayo kwemvura hakuna kunaka seye hydroxyethyl cellulose, uye ine dambudziko rekugadzira gelling kana inopisa. Yepamusoro-yakagadziriswa hydroxypropyl methylcellulose, inogona kuwedzerwa zvakananga kumvura kana ikashandiswa. Mushure mekurunga uye kuparadzira, wedzera alkaline zvinhu zvakaita seammonia mvura kugadzirisa iyo pH kukosha kusvika 8-9, uye kurunga kusvika yanyungudika zvakazara. Kune hydroxypropyl methylcellulose pasina kurapwa kwepamusoro, inogona kunyorova uye yakaputirwa nemvura inopisa inopfuura 85 ° C isati yashandiswa, uye yozonyoroveswa kusvika kune tembiricha yekamuri, yozobvongodzwa nemvura inotonhora kana mvura yechando kuti iparadze zvizere.
②Inorganic thickener
Rudzi urwu rwehupfu hunonyanya kunyanya kushandiswa kwevhu zvigadzirwa, zvakadai se bentonite, magnesium aluminium silicate ivhu, nezvimwewo. Iyo inoratidzirwa mukuwedzera kune iyo thickening mhedzisiro, inewo yakanaka kuturika mhedzisiro, inogona kudzivirira kunyura, uye haizokanganisa kurwisa kwemvura kwekuputira. Mushure mokunge chifukidzo chaomeswa uye chikaumbwa kuva firimu, chinoshanda sechizadziso mufirimu yekuputira, nezvimwewo. Chinhu chisingafadzi ndechekuti chichakanganisa zvakanyanya kuenzana kwekuputira.
③ Synthetic polymer thickener
Synthetic polymer thickeners anonyanya kushandiswa mu acrylic uye polyurethane (associative thickeners). Acrylic thickeners anowanzo acrylic polymers ane carboxyl mapoka. Mumvura ine pH kukosha kwe8-10, boka re carboxyl rinoparadzanisa uye rinoputika; kana iyo pH yakakosha kupfuura gumi, inonyungudika mumvura uye inorasikirwa nekukora mhedzisiro, saka iyo thickening mhedzisiro inonzwa zvakanyanya kune pH kukosha.
The thickening mechanism ye acrylate thickener ndeyokuti zvidimbu zvayo zvinogona kushambadzirwa pamusoro pe latex particles mupende, uye inogadzira jira rekuputira mushure mekuputika kwealkali, iyo inowedzera huwandu hwe latex particles, inodzivisa kufamba kweBrownian kwezvikamu, uye inowedzera viscosity yependi system. ; Chechipiri, kuzvimba kweiyo thickener kunowedzera viscosity yechikamu chemvura.
(2) Pesvedzero ye thickener pane coating properties
Mhedzisiro yerudzi rwe thickener pane rheological zvimiro zvejasi ndeaya anotevera:
Kana huwandu hwekukora huchiwedzera, iyo static viscosity yepende inowedzera zvakanyanya, uye iyo viscosity shanduko yemaitiro inowirirana kana ichiiswa kunze kwesimba rekugera.
Nekuita kwekukora, viscosity yepende inodonha nekukurumidza kana ichiiswa pasi pesimba rekugera, kuratidza pseudoplasticity.
Uchishandisa hydrophobically modified cellulose thickener (yakadai seEBS451FQ), pakakwirira shear rates, viscosity ichiri yakakwirira kana huwandu hwakakura.
Uchishandisa associative polyurethane thickeners (yakadai seWT105A), pakakwirira shear rates, viscosity ichiri yakakwirira kana iyo yakawanda.
Uchishandisa ma acrylic thickeners (akadai seASE60), kunyangwe iyo static viscosity inokwira nekukurumidza kana huwandu hwacho hwakakura, viscosity inodzikira nekukurumidza pamwero wepamusoro weshear.
3. Associative thickener
(1) thickening mechanism
Cellulose ether uye alkali-swellable acrylic thickeners inogona kungowedzera chikamu chemvura, asi haina kuwedzera kune zvimwe zvikamu mupendi yakagadzirwa nemvura, uye haigoni kukonzera kupindirana kukuru pakati pevaravara mupende uye zvikamu zve emulsion, saka Rheology yepende haigoni kugadziriswa.
Associative thickeners inoratidzirwa mukuti kunze kwekukora kuburikidza ne hydration, zvakare inokora kuburikidza nekubatana pakati pavo, nezvikamu zvakapararira, uye nezvimwe zvikamu muhurongwa. Kushamwaridzana uku kunoparadzanisa pamazinga akakwirira ekuveura uye kushamwaridzana zvakare pamutengo wakaderera weshear, zvichiita kuti rheology yejasi igadziriswe.
Iyo yekukora mashandiro eiyo associative thickener ndeyekuti mamorekuru ayo ane linear hydrophilic chain, polymer compound ine lipophilic mapoka kumativi ese ari maviri, kureva kuti, ine hydrophilic uye hydrophobic mapoka muchimiro, saka ine maitiro eiyo surfactant mamorekuru. nature. Mamorekuru akadaro anokora haangogone hydrate uye kuzvimba kuti awedzere chikamu chemvura, asiwo anoumba micelles apo kusangana kweiyo aqueous solution inodarika imwe kukosha. Iyo micelles inogona kushamwaridzana neiyo polymer particles emulsion uye pigment particles zvakashambadza dispersant kuita matatu-dimensional network chimiro, uye akabatana uye akapindwa muropa kuwedzera viscosity yehurongwa.
Chinonyanya kukosha ndechekuti masangano aya ari mumamiriro ekusimba, uye iwo anobatanidzwa micelles anogona kugadzirisa nzvimbo dzawo kana akaiswa kune ekunze masimba, kuitira kuti kupfekedza kuve nekugadzirisa zvinhu. Pamusoro pezvo, sezvo mamorekuru aine micelles akati wandei, chimiro ichi chinoderedza tsika yemamorekuru emvura kutama uye nekudaro inowedzera viscosity yechikamu chemvura.
(2) Basa rekupfekedza
Mazhinji easociative thickeners ma polyurethanes, uye huremu hwawo hwemamorekuru huri pakati pe103-104 maodha ehukuru, maodha maviri ehukuru akaderera pane akajairwa polyacrylic acid uye cellulose thickeners ane huremu hwemamorekuru pakati pe105-106. Nekuda kwehuremu hwakaderera hwema molecular, iyo inobudirira vhoriyamu inowedzera mushure me hydration ishoma, saka viscosity curve yayo inopfava kupfuura yeasina-associative thickeners.
Nekuda kwehuremu hwehuremu hweiyo associative thickener, kupindirana kwayo mukati mechikamu chemvura kunogumira, saka kukora kwayo pachikamu chemvura hakuna kukosha. Mune yakaderera shear rate renji, kutendeuka kwemubatanidzwa pakati pemamorekuru kunopfuura kuparadzwa kwemubatanidzwa pakati pemamorekuru, iyo system yese inochengetedza kumiswa uye kupararira mamiriro, uye viscosity iri padhuze neiyo viscosity yekuparadzira svikiro (mvura). Naizvozvo, iyo associative thickener inoita kuti mvura-based pendi system iratidze yakaderera inooneka viscosity kana iri munzvimbo yakaderera shear rate.
Associative thickeners inowedzera simba rinogona kuitika pakati pemamorekuru nekuda kwekubatana pakati pezvikamu muchikamu chakapararira. Nenzira iyi, simba rakawanda rinodiwa kuputsa kushamwaridzana pakati pemamorekuru pamazinga akakwirira ekuveura, uye simba reshear rinodiwa kuti riwane kufanana kweshear strain yakakurawo, kuitira kuti hurongwa huratidze chiyero chepamusoro cheshear pamazinga akakwirira ekuveura. Kuoneka viscosity. Iyo yakakwirira-shear viscosity uye yakaderera-shear viscosity inogona kungoita kushayikwa kweakajairika thickeners mune rheological maitiro epende, ndiko kuti, iwo maviri thickeners anogona kushandiswa pamwe chete kugadzirisa fluidity yepende yelatex. Kuitwa kwakasiyana-siyana, kusangana nezvinodiwa zvakakwana zvekuputira mufirimu gobvu uye kuyerera kwefirimu.
Nguva yekutumira: Kubvumbi-28-2024