1. Ma'anar da aikin mai kauri
Ana kiran ƙarin abubuwa waɗanda za su iya ƙara ɗanɗanon fenti mai tushen ruwa sosai.
Masu kauri suna taka muhimmiyar rawa wajen samarwa, adanawa da kuma gina rufin.
Babban aikin mai kauri shine ƙara danko na murfin don biyan buƙatun matakai daban-daban na amfani. Duk da haka, danko da murfin ke buƙata a matakai daban-daban ya bambanta. Misali:
A lokacin ajiyar kaya, ana son a sami ɗanko mai yawa don hana launin ya tsaya;
A lokacin aikin gini, yana da kyau a sami matsakaicin danko don tabbatar da cewa fenti yana da kyakkyawan gogewa ba tare da yawan fenti ba;
Bayan an gama ginin, ana fatan cewa danko zai iya komawa cikin danko mai yawa bayan ɗan gajeren lokaci (tsarin daidaita) don hana yin kasa.
Ruwan da ke cikin ruwan ba na Newtonian ba ne.
Idan ɗanɗanon fenti ya ragu tare da ƙaruwar ƙarfin yankewa, ana kiransa da ruwa mai kama da pseudoplastic, kuma yawancin fenti ruwan mai kama da pseudoplastic ne.
Idan yanayin kwararar ruwa mai kama da ruwa mai kama da ruwa yana da alaƙa da tarihinsa, wato, yana dogara ne akan lokaci, ana kiransa ruwan thixotropic.
Lokacin da muke ƙera murfin, sau da yawa muna ƙoƙarin yin murfin thixotropic, kamar ƙara ƙarin abubuwa.
Idan thixotropy na shafa ya dace, zai iya magance saɓani na matakai daban-daban na shafa, da kuma biyan buƙatun fasaha na bambancin danko na shafa a cikin matakan ajiya, matakin gini, da bushewa.
Wasu masu kauri na iya ba wa fentin babban thixotropy, ta yadda zai sami ɗanko mai yawa a lokacin hutawa ko kuma a ƙarancin saurin yankewa (kamar ajiya ko jigilar kaya), don hana launin fenti a cikin fenti ya kwanta. Kuma a ƙarƙashin babban saurin yankewa (kamar tsarin rufewa), yana da ƙarancin ɗankowa, don haka murfin yana da isasshen kwarara da daidaitawa.
Ana wakiltar Thixotropy ta hanyar thixotropic index TI kuma ana auna shi ta hanyar Brookfield viscometer.
TI=danko (an auna a 6r/min)/danko (an auna a 60r/min)
2. Nau'ikan masu kauri da tasirinsu akan halayen shafa
(1) Nau'i Dangane da sinadaran da ke cikinsa, an raba kauri zuwa rukuni biyu: na halitta da na rashin halitta.
Nau'ikan da ba su da sinadarai masu gina jiki sun haɗa da bentonite, attapulgite, aluminum magnesium silicate, lithium magnesium silicate, da sauransu, nau'ikan halitta kamar methyl cellulose, hydroxyethyl cellulose, polyacrylate, polymethacrylate, acrylic acid ko methyl Acrylic homopolymer ko copolymer da polyurethane da sauransu.
Daga mahangar tasirin da ke kan halayen rheological na shafa, an raba masu kauri zuwa masu kauri thixotropic da masu kauri associative. Dangane da buƙatun aiki, adadin mai kauri ya kamata ya zama ƙasa kuma tasirin kauri yana da kyau; ba abu ne mai sauƙi a lalata shi ta hanyar enzymes ba; lokacin da zafin jiki ko ƙimar pH na tsarin ya canza, ɗanko na murfin ba zai ragu sosai ba, kuma ba za a yi amfani da launin da abin cikawa ba. ; Kyakkyawan kwanciyar hankali na ajiya; kyakkyawan riƙe ruwa, babu wani abin da ke bayyana kumfa kuma babu mummunan tasiri akan aikin fim ɗin rufewa.
①Mai kauri cellulose
Kauri na cellulose da ake amfani da shi a cikin shafa sune galibi methylcellulose, hydroxyethylcellulose da hydroxypropylmethylcellulose, kuma na biyun an fi amfani da su.
Hydroxyethyl cellulose wani samfuri ne da aka samu ta hanyar maye gurbin ƙungiyoyin hydroxyl akan raka'o'in glucose na cellulose na halitta da ƙungiyoyin hydroxyethyl. Musamman ana bambanta ƙayyadaddun bayanai da samfuran samfuran gwargwadon matakin maye gurbin da danko.
An kuma raba nau'ikan hydroxyethyl cellulose zuwa nau'in narkewa na yau da kullun, nau'in watsawa cikin sauri da nau'in kwanciyar hankali na halitta. Dangane da hanyar amfani, ana iya ƙara hydroxyethyl cellulose a matakai daban-daban a cikin tsarin samar da shafi. Ana iya ƙara nau'in watsawa cikin sauri kai tsaye a cikin nau'in busasshen foda. Duk da haka, ƙimar pH na tsarin kafin a ƙara ya kamata ya zama ƙasa da 7, galibi saboda hydroxyethyl cellulose yana narkewa a hankali a ƙarancin ƙimar pH, kuma akwai isasshen lokaci don ruwa ya shiga cikin cikin ƙwayoyin, sannan a ƙara ƙimar pH don ya narke da sauri. Hakanan ana iya amfani da matakan da suka dace don shirya wani taro na maganin manne da ƙara shi zuwa tsarin rufewa.
Hydroxypropyl methylcellulosesamfuri ne da aka samu ta hanyar maye gurbin rukunin hydroxyl akan sashin glucose na cellulose na halitta da rukunin methoxy, yayin da ɗayan ɓangaren kuma aka maye gurbinsa da rukunin hydroxypropyl. Tasirin kauri nasa iri ɗaya ne da na hydroxyethyl cellulose. Kuma yana da juriya ga lalacewar enzymatic, amma narkewar ruwansa bai yi kyau kamar na hydroxyethyl cellulose ba, kuma yana da rashin amfani da gelling lokacin da aka dumama shi. Ga hydroxypropyl methylcellulose da aka yi wa magani a saman, ana iya ƙara shi kai tsaye zuwa ruwa lokacin amfani. Bayan juyawa da warwatsewa, ƙara abubuwan alkaline kamar ruwan ammonia don daidaita ƙimar pH zuwa 8-9, sannan a juya har sai ya narke gaba ɗaya. Don hydroxypropyl methylcellulose ba tare da maganin saman ba, ana iya jiƙa shi kuma a kumbura shi da ruwan zafi sama da 85°C kafin amfani, sannan a sanyaya shi zuwa zafin ɗaki, sannan a juya shi da ruwan sanyi ko ruwan ƙanƙara don narke shi gaba ɗaya.
②Mai kauri mara tsari
Wannan nau'in mai kauri galibi wasu samfuran yumbu ne masu aiki, kamar bentonite, yumbun magnesium aluminum silicate, da sauransu. An siffanta shi da cewa baya ga tasirin kauri, yana kuma da kyakkyawan tasirin dakatarwa, yana iya hana nutsewa, kuma ba zai shafi juriyar ruwa na murfin ba. Bayan an busar da murfin kuma ya zama fim, yana aiki a matsayin mai cikewa a cikin fim ɗin rufewa, da sauransu. Abin da ba shi da kyau shi ne zai yi tasiri sosai ga matakin murfin.
③ Mai ɗaure polymer na roba
Ana amfani da masu kauri na polymer na roba galibi a cikin acrylic da polyurethane (masu kauri na haɗin gwiwa). Masu kauri na acrylic galibi polymers ne na acrylic waɗanda ke ɗauke da ƙungiyoyin carboxyl. A cikin ruwa mai ƙimar pH na 8-10, ƙungiyar carboxyl tana rabuwa kuma tana kumbura; lokacin da ƙimar pH ta fi 10, tana narkewa a cikin ruwa kuma tana rasa tasirin kauri, don haka tasirin kauri yana da matukar tasiri ga ƙimar pH.
Tsarin kauri na mai kauri acrylate shine cewa ana iya shanye ƙwayoyinsa a saman ƙwayoyin latex a cikin fenti, kuma su samar da wani Layer na rufi bayan kumburin alkali, wanda ke ƙara yawan ƙwayoyin latex, yana hana motsin Brownian na ƙwayoyin, kuma yana ƙara danko na tsarin fenti. ; Na biyu, kumburin mai kauri yana ƙara danko na matakin ruwa.
(2) Tasirin mai kauri akan halayen shafi
Tasirin nau'in mai kauri akan halayen rheological na shafi kamar haka:
Idan adadin kauri ya ƙaru, tozarcin fenti yana ƙaruwa sosai, kuma yanayin canjin danko yana daidai lokacin da aka yi amfani da ƙarfin yankewa na waje.
Da tasirin mai kauri, danko na fenti yana raguwa da sauri idan aka yi masa rauni, wanda hakan ke nuna cewa yana da kama da na roba.
Ta amfani da na'urar kauri ta cellulose da aka gyara ta hanyar hydrophobic (kamar EBS451FQ), a yawan yankewa, danko har yanzu yana da yawa idan adadin ya yi yawa.
Ta amfani da ma'aunin polyurethane mai kauri (kamar WT105A), a yawan yankewa, danko har yanzu yana da yawa idan adadin ya yi yawa.
Ta amfani da masu kauri acrylic (kamar ASE60), kodayake danko mai tsauri yana ƙaruwa da sauri lokacin da adadin ya yi yawa, danko yana raguwa da sauri a mafi girman ƙimar yankewa.
3. Mai kauri mai haɗawa
(1) tsarin kauri
Masu kauri acrylic masu cellulose ether da alkali masu kumburi na iya kauri matakin ruwa kawai, amma ba su da wani tasiri mai kauri akan sauran abubuwan da ke cikin fenti mai tushen ruwa, kuma ba za su iya haifar da muhimmiyar hulɗa tsakanin launukan da ke cikin fenti da barbashi na emulsion ba, don haka ba za a iya daidaita ilimin halittar fenti ba.
Ana siffanta masu kauri masu alaƙa da juna ta hanyar cewa ban da kauri ta hanyar ruwa, suna kuma kauri ta hanyar haɗin kai tsakanin su, da barbashi da aka warwatse, da kuma sauran abubuwan da ke cikin tsarin. Wannan haɗin yana rabuwa a cikin yawan yankewa kuma yana sake haɗuwa a cikin ƙarancin yankewa, yana ba da damar daidaita rheology na murfin.
Tsarin kauri na mai kauri na haɗin gwiwa shine cewa kwayar halittarsa sarkar hydrophilic ce mai layi, wani mahaɗin polymer tare da ƙungiyoyin lipophilic a ƙarshen biyu, wato, yana da ƙungiyoyin hydrophilic da hydrophobic a cikin tsarin, don haka yana da halayen ƙwayoyin surfactant. yanayi. Irin waɗannan ƙwayoyin mai kauri ba wai kawai suna iya shayar da ruwa da kumbura don su kauri matakin ruwa ba, har ma suna samar da micelles lokacin da yawan ruwan da ke cikin ruwan ya wuce wani ƙima. Micelles na iya haɗawa da ƙwayoyin polymer na emulsion da ƙwayoyin pigment waɗanda suka sha mai rarrabawa don samar da tsarin hanyar sadarwa mai girma uku, kuma suna da alaƙa kuma suna haɗuwa don ƙara danko na tsarin.
Abin da ya fi muhimmanci shi ne cewa waɗannan alaƙar suna cikin yanayin daidaito mai ƙarfi, kuma waɗannan ƙwayoyin halittar da ke da alaƙa za su iya daidaita matsayinsu lokacin da aka fuskanci ƙarfin waje, don haka rufin yana da halayen daidaita daidaito. Bugu da ƙari, tunda ƙwayoyin halittar suna da ƙwayoyin halittar da yawa, wannan tsari yana rage yanayin ƙwayoyin halittar ruwa na ƙaura don haka yana ƙara ɗanko na matakin ruwa.
(2) Matsayin da ke cikin rufewa
Yawancin masu kauri masu haɗin gwiwa polyurethanes ne, kuma nauyin kwayoyin halittarsu yana tsakanin girman 103-104, girman girma biyu ƙasa da na yau da kullun polyacrylic acid da masu kauri cellulose tare da nauyin kwayoyin halitta tsakanin 105-106. Saboda ƙarancin nauyin kwayoyin halitta, ƙaruwar yawan da ke tasiri bayan ruwa ya ragu, don haka lanƙwasa mai kama da shi ya fi na masu kauri marasa haɗin kai kyau.
Saboda ƙarancin nauyin ƙwayoyin halitta na mai kauri mai haɗawa, haɗuwar sa tsakanin ƙwayoyin halitta a cikin matakin ruwa yana da iyaka, don haka tasirin kauri a matakin ruwa ba shi da mahimmanci. A cikin ƙarancin saurin yankewa, sauyawar haɗin gwiwa tsakanin ƙwayoyin halitta ya fi lalacewa tsakanin ƙwayoyin halitta, tsarin gaba ɗaya yana riƙe da yanayin dakatarwa da warwatsewa, kuma danko yana kusa da danko na matsakaicin watsawa (ruwa). Saboda haka, mai kauri mai haɗawa yana sa tsarin fenti mai tushen ruwa ya nuna ƙarancin danko a bayyane lokacin da yake cikin yankin ƙarancin saurin yankewa.
Masu kauri masu haɗin gwiwa suna ƙara ƙarfin kuzari tsakanin ƙwayoyin halitta saboda alaƙar da ke tsakanin ƙwayoyin halitta a cikin matakin da aka warwatse. Ta wannan hanyar, ana buƙatar ƙarin kuzari don karya alaƙar da ke tsakanin ƙwayoyin halitta a cikin yawan yankewa, kuma ƙarfin yankewa da ake buƙata don cimma irin wannan nau'in yankewa shi ma ya fi girma, don haka tsarin yana nuna ƙimar yankewa mafi girma a cikin yawan yankewa mai yawa. Danko a bayyane yake. Babban danko mai girma da ƙarancin danko mai ƙarancin yankewa na iya rama rashin ƙarancin masu kauri gama gari a cikin halayen rheological na fenti, wato, ana iya amfani da masu kauri biyu a haɗe don daidaita ruwan fenti na latex. Canjin aiki, don biyan buƙatun gama gari na shafawa cikin fim mai kauri da kwararar fim ɗin rufi.
Lokacin Saƙo: Afrilu-28-2024