Isishwankathelo sokusetyenziswa kweiiarhente zokudibanisa i-amino resin
Indima ephambili yee-amino resins (i-melamine-formaldehyde, i-benzomelamine-formaldehyde, kunye nee-urea-formaldehyde resins) kwiingubo ze-thermosetting kukudibanisa iimolekyuli eziphambili zokwenza ifilimu kwisakhiwo senethiwekhi esinemilinganiselo emithathu ngokusebenzisa ii-chemical reactions. Olu lwakhiwo lwenethiwekhi lufumaneka ngokusabela kwee-amino resin molecules kunye namaqela asebenzayo kwiimolekyuli zokwenza ifilimu, kwaye ngaxeshanye ngokusebenzisa i-condensation polymerization kunye nezinye iimolekyuli ze-amino resin. Ii-amino resins zisabela ngokulula kwiipolymers eziqulathe amaqela e-hydroxyl aphambili nawesibini, amaqela e-carboxyl, kunye namaqela e-amide; ke ngoko, ii-amino resins zisetyenziswa rhoqo kwiinkqubo zokupenda ezisekwe kwi-acrylic, polyester, alkyd, okanye epoxy resins.
Ii-amino resins zikwasetyenziswa kwiinkqubo ze-polyurethane njengezongezo zokugquma ukuphucula ukusebenza ngokubanzi kokugquma kwizicelo ezithile.
Umgaqo wee-amino resins:
Ukubaluleka kwee-amino resins kwiivarnish zokubhaka kudlula kakhulu umlinganiselo wazo kwiingubo. Ukuqonda indlela yokusebenzisa iipropati zeekhemikhali zee-amino resins kuyilo lwendlela yokwenza iingubo kuya kuba baluleke ngakumbi. Umzekelo,Ukuba abaqulunqi bokugquma abanelisekanga ziimpawu ezithile zefilimu yokugquma, banokuzilungisa besebenzisa ezi ndlela zilandelayo:
1. Ukuphuculwa okanye ukukhethwa ngokutsha kwe-resin eyenza ifilimu ngokwayo;
2. Ukukhethwa kwee-amino resins (i-methyl etherification okanye i-butyl etherification, kunye nokukhethwa komgangatho we-etherification, njl.njl.);
3. Umlinganiselo we-resin eyenza ifilimu kwi-amino resin.
4. Ukukhetha iCatalyst (nokuba kufuneka uyidibanise okanye ungayifaki, kwaye kufuneka wongeze malini).
Onke amanqaku amane angentla, ngaphandle kwelokuqala,Iipropati zee-amino resins zixhomekeke kumaqela azo asebenzayo kunye nomsebenzi wazo; ngoko ke, ukuqonda ulwakhiwo lwee-amino resins kubalulekile. Nangona kunjalo, ngaphambi kokuba uqonde ii-amino resins, kubalulekile ukuba nolwazi olusisiseko ngee-host resins ezisetyenziswa kunye nazo.
Njengoko bekutshiwo ngaphambili, ii-amino resins zisetyenziswa kakhulu.isetyenziswa kunye nee-alkyd resins, ii-acrylic resins, ii-polyester resins, kunye nee-epoxy resins. Ii-resin ze-alkyd zenziwe ngokuyintloko kwii-polyols kunye nee-polyacid resins ngokusebenzisa i-esterification. Ngexesha lokwenziwa, ii-alcohols zihlala zininzi kakhulu; amanye amaqela e-carboxyl ee-polyacids asenokungasabeli ngokupheleleyo, nto leyo ebangela ukuba ii-resin ze-alkyd ziqulathe inani elithile lamaqela e-carboxyl kunye ne-hydroxyl. Inani lamaqela e-carboxyl kunye ne-hydroxyl lidla ngokubonakaliswa lixabiso le-asidi kunye nexabiso le-hydroxyl. Ixabiso le-asidi libhekisa kwinani lee-milligrams ze-KOH ezifunekayo ukuze kuncitshiswe i-1g ye-resin eqinileyo ngokuyi-titration nge-KOH. Ixabiso le-hydroxyl libhekisa kwinani lee-milligrams ze-KOH ezifunekayo ukuze kuncitshiswe ngokupheleleyo amaqela e-OH kwi-1g ye-resin eqinileyo ngokuyi-titration nge-KOH. Ngokufanayo, ii-resin ze-polyester, ii-resin ze-acrylic, kunye nee-amino resins nazo ziqulathe inani elithile lamaqela e-carboxyl kunye ne-hydroxyl. Umahluko ukwizinto ezisetyenzisiweyo ukwenza ii-resins; umzekelo, amaqela e-carboxyl kwi-resins ze-acrylic avela kwi-acrylic acid, kwaye amaqela e-hydroxyl avela kwi-hydroxyacrylic acid. Ubungakanani bamaqela e-carboxyl kunye ne-hydroxyl kwii-amino resins nabo bahlukile. Ixabiso le-asidi, ixabiso le-hydroxyl, kunye ne-viscosity zonke zizibonakaliso ezibalulekileyo zee-resins, ezichaphazela ngqo ukusebenza kwazo.
Ukubuyela kwisihloko see-amino resins, masiqale sijonge ulwakhiwo lwazo:
Umfanekiso 1:
Umfanekiso 2
Umfanekiso 1 ubonisa i-amino resin ene-alkylated encinci equlethe amaqela e-alkoxy, i-imino, kunye ne-hydroxymethyl. Ukuba sicinga ngendandatho enamalungu amathandathu eyenziwe zii-athomu ze-carbon ne-nitrogen njengesakhelo, amasebe okanye izakhiwo ezivela kuyo zinokuchazwa ngokomfuziselo njengezineentloko ezintathu kunye neengalo ezintandathu. Utshintsho oluninzi kwiipropati zee-amino resin lubangelwa ngqo kumahluko kwezi "ngalo" zintandathu kunye nolungelelwaniso lwazo oluntsonkothileyo kunye nokudibanisa kwazo.
Umfanekiso 2 ubonisa isakhiwo se-HMMM esilinganayo kakhulu, oko kukuthi, i-amino resin egcwele i-methylated, eneqela elinye elisebenzayo: iqela le-methoxy, eliyi-idealized. Ekubeni inqanaba le-etherification lingenakufikelela kwi-1:6 (eliphezulu) kwimveliso yokwenyani, i-amino resin ebizwa ngokuba yi-fullly methylated resin iya kuhlala iqulethe amaqela athile e-imino kunye ne-hydroxymethyl.
Masiqale ngokuqonda imigaqo yee-amino resins ukuze sifunde ngeempawu zazo:
Inyathelo lokuqala ekudibaniseni i-resin kukwenza i-melamine ne-formaldehyde xa kukho i-catalyst ukuze yenze i-polyhydroxymethyl melamine. Zonke ii-athomu ze-hydrogen ezisebenzayo kwi-triazine ring zinokuguqulwa zibe ngamaqela e-hydroxymethyl, kodwa eneneni, zii-moles ezi-2 ukuya kwezi-6 ze-formaldehyde ezisabela kwi-triazine ring. Ii-athomu ze-hydrogen ezisebenzayo ezingekaphendulwa zimelwe ngamaqela e-imino. Njengoko siza kubona kamva, la maqela adlala indima ebalulekileyo kwinkqubo yokunyanga ngokusebenzisa i-self-condensation polymerization.
I-Polyhydroxymethyl melamine ayizinzanga kakhulu kwaye inokunyibilika okulinganiselweyo kwizinyibilikisi zokugquma eziqhelekileyo. Ii-amino resins ngokuyintloko zisebenza njengee-agents zokugquma kunye nokuphilisa kwiingubo. Ukuze kwenziwe i-arhente efanelekileyo yokugquma efanelekileyo kwiingubo, iqela le-hydroxymethyl lidla ngokunyibilikiswa nge-short-chain alcohol ukunciphisa ukusebenza kwayo kunye nokuphucula ukuhambelana kwayo nezinto zefilimu eziqhelekileyo kunye nezinyibilikisi ze-aliphatic. I-Methanol kunye ne-butanol zihlala zisetyenziswa njenge-short-chain alcohols. Ngokulawula ubungakanani be-methanol okanye i-butanol eyongeziweyo kunye nezinye iimeko, ii-amino resins ezinee-degrees ezahlukeneyo ze-etherification zinokufunyanwa.
Kuphela ziindawo eziye zasabela kwi-formaldehyde (amaqela e-hydroxymethyl) ezinokugqunywa zii-alcohols; ii-athomu ze-hydrogen ezingasabelanga (amaqela e-imino) azisabela kwi-short-chain alcohols. Ngaphezu koko, le mpendulo ibonisa ukuba onke amaqela amathandathu e-hydroxymethyl asabela kwi-alcohols ukuze enze i-hexaalkoxymethyl melamine, oko kuthetha ukuba impendulo yeqela elinye ukuya kwamathandathu e-hydroxymethyl ene-alcohols inokulawulwa ngokwenene. Yingakho sineentlobo ezahlukeneyo zee-amino resin.
Ukuzilungisa ngokwakho ii-amino resins :
Ubunzima beemolekyuli zee-amino resins bumiselwa bubungakanani bokuzifunxa okanyeukudibanisa okunqamlezileyophakathi kwamaqela asebenzayo (imino, i-hydroxymethyl, i-alkoxymethyl) kwiringi ye-triazine kunye neemolekyuli ze-melamine. Ekusetyenzisweni kwayo, inqanaba le-polymerization edibanisayo lichaphazela kakhulu ubunzima be-molecular ye-amino resin kunye nokusebenza kwefilimu yokugquma.
Impendulo yokuzifutha kwee-amino resins inokwenzeka ngale ndlela ilandelayo:
Umfanekiso 3:
Impendulo ekhohlo yenza ibhulorho ye-methylene, ngelixa impendulo esekunene yenza ibhulorho ye-methylene ether. Inqanaba lokubhida kwii-amino resins lidla ngokubonakaliswa njengenqanaba le-polymerization (DP): DP = ubunzima bemolekyuli / ubunzima besangqa ngasinye se-triazine. Ii-amino resins zokuqala zazizi-polymerisator, kunye ne-DP > 3.0. Uphuhliso lwetekhnoloji lwenze kwaba nokwenzeka ukunciphisa ukuzijikisa kwii-amino resins ezigqityiweyo. Okwangoku, ii-melamine resins ezithengiswayo zine-DPs eziphantsi njenge-1.1.
Impembelelo ephambili yobunzima be-amino resin molecular ibonakala kwi-coating viscosity. Ii-melamine resin ezine-DP > 2.0 kufuneka zixutywe ne-solvent ukuya kwi-50%–80% ye-solids ukuze kufezekiswe i-viscosity efanelekileyo. Ii-melamine resin ze-monomer-type ezine-DP phakathi kwe-1.1 kunye ne-1.5 zihlala zibonelelwa kwi-100% ye-solids esebenzayo; i-solvents ezongezelelweyo zinempembelelo enkulu kwi-VOCs ye-coating egqityiweyo. Ubunzima be-molecular bee-amino resin bukwachaphazela i-coating curing reaction kunye ne-film properties. Inkqubo ye-coating esebenzisa i-high-DP amino resin iya kufikelela kwi-crosslinking density echaziweyo ngexesha elifutshane kune-coating system esebenzisa i-amino resin enesakhiwo esifanayo kodwa i-DP ephantsi. Ke ngoko, i-coatings equlethe ii-high-DP crosslinking agents zifuna i-catalyst encinci okanye i-weaker acid catalyst ukuze kufezekiswe imeko efanayo ye-curing. Impembelelo yobunzima be-molecular kwiipropati zefilimu ikwi-flexibility range. I-coatings enyangiweyo ngee-amino resin ze-high-DP ziqulathe ipesenti ephezulu yee-amino-amino bonds kunye nee-amino-lacquer bonds ezimbalwa. Olu hlobo lwesakhiwo senethiwekhi edibanisayo lwenza ulwelo olunobunzima obuhle kodwa lunokuba buthathaka. Oku ngamanye amaxesha kunokulungiswa ngokukhetha i-resin yepeyinti eguquguqukayo ngakumbi. Nangona kunjalo, usetyenziso olufuna ulwelo oluguquguqukayo kakhulu ludla ngokufuna ii-amino resins ze-monomeric.
Iipolyester eziqulathe amaqela e-carboxyl zinokusabela kunye ne-melamine-formaldehyde ukuvelisa iingubo eziluncedo zokubeka umphezulu we-thermosetting ezineempawu ezahlukeneyo zomzimba.
Iiresini ezininzi ze-melamine-formaldehyde ezine-butylated ziyasebenza kurhwebo, ngokuyintloko ngenxa yomahluko kwinqanaba lokuqala le-polymerization (ubunzima bemolekyuli) kunye nomlinganiselo wamaqela e-alkoxy kulawo angenawo amaqela e-hydroxymethyl kunye nee-amino hydrogens. Olu mahluko luchaphazela i-liquid viscosity, ukuhambelana kwe-melamine ne-polyester, kunye nesantya sokuphiliswa kwe-enamel. Iiresini ze-melamine zendabuko, ezisabela namaqela e-side hydroxyl, ngokuyintloko zidibanisa iimolekyuli ze-polyester. Ekubeni i-crosslinking reaction i-acid-catalyzed, kumaqondo obushushu aphakathi kwe-120°C kunye ne-150°C, ii-asidi ezinamandla zihlala zichaphazela i-crosslinking reaction yeeresini ze-polyester; nangona kunjalo, ezinye ii-polyester zifuna i-acid catalysis eyongezelelweyo kwii-asidi ezibuthathaka kakhulu ukuze zinyange inkqubo ye-enamel.
Kukho le nto ilandelayo: Ukongeza kwi-crosslinking reaction ye-melamine-polyester, i-butylated melamine-formaldehyde resin ikwafumana i-self-condensation reaction. Oko kukuthi, i-amino resin ifumana i-self-crosslinking ukwenza isakhiwo senethiwekhi ye-melamine. Le reaction yenzeka ngaxeshanye ne-melamine-polyester reaction kwaye yi-reaction ekhuphisanayo. Isizathu sale reaction kukuba, ukongeza kumaqela e-butoxy, i-butylated melamine-formaldehyde resin ikwanamaqela e-hydrocarbon methyl akhululekileyo kunye ne-hydrogen evela kumaqela e-imino, onke anokusabelana. Nje ukuba i-amino resin ifumane i-self-crosslinking, iya kulahlekelwa yiminye yemisebenzi yayo.
Nangona ukuzidibanisa ngokuzenzekelayo kudla ngokwenza ukuba iingubo zibe lukhuni ngakumbi kwaye zingabi nakumelana neekhemikhali, oku kubangela ukulahleka okukhulu kokuguquguquka. Ukuze kufumaneke ukuguquguquka okwaneleyo kwiivarnish zepolyester...
I-Hexamethoxymethyl melamine (HMMM) yi-amino resin ene-hydroxymethyl ngokupheleleyo kwaye ine-methylation epheleleyo. Njenge-butylated melamine-formaldehyde, ifumana i-cross-linking reaction kunye namaqela e-hydroxyl e-polyester resin xa ifudunyezwa, yenze i-non-softening solid. Ngokwenyani, ngaphandle kwe-asidi catalyst, i-HMMM ayizukuzifumana i-self-crosslinking nokuba ixesha elide okanye ubushushu bunyukile. Nangona kunjalo, i-bulk HMMM iya kufumana i-self-crosslinking reaction kwi-150°C xa kukho i-asidi catalyst enamandla. Ngokwahlukileyo koko, nokuba akukho asidi enamandla, i-butylated melamine eqhelekileyo kunye ne-urea resin ziya kufumana i-self-crosslinking reaction enamandla kunye nobushushu obukhulayo.
Impendulo yokunyanga yee-amino resins:
Ekubeni ii-amino resins zisetyenziselwa ukudibanisa iimolekyuli eziphambili zokwenza ifilimu kwisakhiwo senethiwekhi, i-co-condensation reaction yee-amino resins kunye nee-paint resins inomdla kakhulu. Umzekelo oqhelekileyo yi-etherification (exchange) reaction.amaqela e-hydroxyl kwiiresini zepeyinti kunye namaqela e-alkoxymethyl kwiiresini ze-amino.
Phantsi kweemeko zobushushu kunye nee-asidi catalysts (ngokwesiqhelo iimeko zokuphilisa), ukudityaniswa kwenzeka ngokukhawuleza, kudibanisa onke amaqela e-hydroxyl afumanekayo kwipeyinti. Enyanisweni, njengoko ulwakhiwo lwenethiwekhi yepolymer lusenziwa, ukutyibilika kwee-reactants kuncipha, okushiya amanye amaqela e-hydroxyl engasabelanga. Ngokubanzi, xa kukho i-amino resin engaphezulu kwi-coating xa kuthelekiswa nomlinganiselo ofanelekileyo, amaqela aseleyo e-alkoxy anokuthatha inxaxheba kwezinye ii-reactions okanye ahlale engasabelanga kwifilimu yokugquma. Njengoko bekutshiwo ngaphambili, ii-amino resin ziyazixuba ngokulula kwaye zisabelane, nto leyo ebangela ukwanda kobunzima be-molecular ngexesha lokuveliswa. Ezi mpendulo zikwavela ngexesha lokugquma. Ke ngoko, endaweni yokuba yinto engalunganga, inqanaba elithile lokuzixuba kwee-amino resin kubalulekile ukuze kufunyanwe i-polymer matrix eqinileyo, epakishwe ngokuqinileyo. Onke amaqela amathathu asebenzayo e-amino resin athatha inxaxheba kwii-reaction zokuzixuba, kwaye kwii-alkylated ngokupheleleyo i-melamine resin coating catalyst catalyzed yi-acids ezinamandla, kukho ubungqina bokuba ezi mpendulo zenzeka emva kokutshintshana kwe-ether ne-coating resin. Xa kungekho zi-catalysts zangaphandle okanye ii-catalysts ze-asidi ebuthathaka, ezi mpendulo zokuzidibanisa zenzeka kakhulu kwiinkqubo ze-melamine resin ezine-imino/okanye i-hydroxymethyl ephezulu. Kuzo zombini iimeko, impendulo yokuzidibanisa kancinci ibalulekile ekwakheni isakhiwo esihle senethiwekhi.
Ngexesha lokucocwa kwe-amino resin crosslinked coatings, ezinye ii-reaction ezenzekayo kukususwa kwe-formaldehyde kunye ne-hydrolysis. Ukususwa kwe-formaldehyde kwenzeka ngokukhawuleza kumaqondo obushushu aqhelekileyo okucocwa, phantse yisona sizathu sokukhululwa kwe-formaldehyde ngexesha lokucocwa kwe-amino resin; enye i-formaldehyde yi-free formaldehyde.
Xa ii-amino resin zidibana ukuze zenze iifilimu kwaye ziphile, ezinye ii-hydrolysis reactions zenzeka. Ngexesha lale nkqubo, amanye amaqela e-alkoxymethyl aguqulwa abe ngamaqela e-hydroxymethyl. I-hydrolysis yee-melamine resin ezinomxholo ophezulu we-imino okanye i-hydroxymethyl inokuqalwa yi-alkalis, kwaye inokwenzeka kancinci kubushushu begumbi. Oku kwenza ii-amino resin zithambekele ngakumbi ekuziqhelaniseni, okukhokelela ekwandeni kwe-viscosity yengubo ngexesha lokugcina. Ukuthintela oku, ii-melamine resin ezigcwele i-methylated okanye ii-co-solvents ezixhathisa i-alkali hydrolysis zingasetyenziswa kwiingubo ezisekelwe emanzini. Ii-melamine resin ezigcwele i-alkylated zixhathisa i-alkali-catalyzed hydrolysis kwiinkqubo ezisekelwe emanzini. Ii-melamine resin ezigcwele i-alkylated kunye ne-alkylated inxalenye ye-alkyle azixhathisi kwi-hydrolysis equlathe i-acid kwiinkqubo ezisekelwe emanzini; ke ngoko, kufuneka kusetyenziswe i-asidi catalyst evaliweyo kwinkqubo esekwe emanzini.
Ukuba ufuna ukwazi okungakumbiiarhente yokudibanisaiimveliso, zive ukhululekile ukunxibelelana nathi.
Ixesha leposi: Disemba-19-2025