Pfupiso yekushandiswa kweamino resin crosslinking agents
Basa guru remaamino resins (melamine-formaldehyde, benzomelamine-formaldehyde, uye urea-formaldehyde resins) mu thermosetting coatings nderekubatanidza mamorekuru makuru anogadzira firimu kuita chivakwa che network chine mativi matatu kuburikidza ne chemical reactions. Chivakwa ichi che network chinowanikwa kuburikidza ne reaction yemaamino resin molecules ne functional groups pama molecules ekugadzira firimu, uye panguva imwe chete kuburikidza ne condensation polymerization nemamwe ma amino resin molecules. Ma amino resins anokurumidza kuita nema polymers ane primary ne secondary hydroxyl groups, carboxyl groups, uye amide groups; saka, ma amino resins anowanzo shandiswa muma pendi systems akavakirwa pa acrylic, polyester, alkyd, kana epoxy resins.
MaAmino resins anoshandiswawo muma polyurethane systems sekuwedzera kwekuputira kuti zvivandudze mashandiro ese ekuputira kune mamwe mashandisirwo.
Nheyo yemaamino resins:
Kukosha kwemaamino resins mumavarnish ekubikisa kunopfuura zvakanyanya huwandu hwawo mukuputira. Kunzwisisa mashandisirwo emakemikari emaamino resins mukugadzira kuputira kuri kuramba kuchikosha. Semuenzaniso,Kana vagadziri vemachira vasina kugutsikana nezvimwe zvinhu zvefirimu remachira, vanogona kuzvigadzirisa vachishandisa nzira dzinotevera:
1. Kuvandudzwa kana kusarudzwa patsva kweresin inogadzira firimu pachayo;
2. Kusarudzwa kwemaamino resins (methyl etherification kana butyl etherification, uye kusarudzwa kwedanho re etherification, nezvimwewo);
3. Chiyero cheresin inogadzira firimu kune amino resin.
4. Sarudzo yeCatalyst (kungave kuwedzera kana kusawedzera, uye kuti kuwedzera kwakadii).
Pfungwa ina dzese dziri pamusoro apa, kunze kweyekutanga,zvine chekuita nemaamino resins. Hunhu hwemaamino resins hunoenderana nemapoka adzo anoshanda uye mashandiro adzo; saka, kunzwisisa maumbirwo emaamino resins kwakakosha. Zvisinei, usati wanzwisisa maamino resins, zvakakosha kuti uve neruzivo rwekutanga rwemahosi resins anoshandiswa pamwe chete nawo.
Sezvambotaurwa, ma amino resins anonyanya kushandiswainoshandiswa pamwe chete nema alkyd resins, acrylic resins, polyester resins, uye epoxy resins.. MaAlkyd resin anonyanya kugadzirwa kubva kumapolyols nemapolyacid resin kuburikidza ne esterification. Munguva yekugadzira, maalcohols anowanzo kuve akawandisa; mamwe mapoka ecarboxyl emapolyacids anogona kusaita zvachose, zvichikonzera kuti maalkyd resin ane huwandu hwakati hwemacarboxyl nemahydroxyl groups. Huwandu hwemacarboxyl nemahydroxyl groups hunowanzo kuratidzwa nekukosha kweasidhi uye hydroxyl. Kukosha kweasidhi kunoreva huwandu hwemamilligrams eKOH anodiwa kuti abvise 1g yesolid resin ne titration neKOH. Kukosha kwehydroxyl kunoreva huwandu hwemamilligrams eKOH anodiwa kuti abvise zvachose mapoka eOH mu1g yesolid resin ne titration neKOH. Saizvozvowo, mapolyester resin, acrylic resin, uye amino resin zvinewo huwandu hwakati hwemacarboxyl nemahydroxyl groups. Musiyano uri muzvinhu zvinoshandiswa kugadzira maresins; semuenzaniso, mapoka ecarboxyl muma acrylic resin anobva ku acrylic acid, uye mapoka ehydroxyl anobva ku hydroxacrylic acid. Huwandu hwemapoka ecarboxyl nehydroxyl mumaamino resins hunosiyanawo. Kukosha kweasidhi, kukosha kwehydroxyl, uye viscosity zvese zviratidzo zvakakosha zvemaresins, zvichikanganisa kushanda kwawo zvakananga.
Tichidzokera kunyaya yema amino resins, ngatitangei tatarisa chimiro chawo:
Mufananidzo 1:
Mufananidzo 2
Mufananidzo 1 unoratidza amino resin ine alkylated zvishoma ine mapoka ealkoxy, imino, uye hydroxymethyl. Kana tikafunga nezve ring ine nhengo nhanhatu inoumbwa nemaatomu ekabhoni nenitrogen se skeleton, matavi kana maumbirwo anobva mairi anogona kutsanangurwa nenzira yekufananidzira seane misoro mitatu nemaoko matanhatu. Kusiyana kukuru muhunhu hweamino resin kunokonzerwa chaizvo nekusiyana kwe "maoko" aya matanhatu uye kurongeka kwawo kwakaoma uye kusanganiswa kwawo.
Mufananidzo 2 unoratidza chimiro cheHMMM chakaenzana zvakanyanya, kureva, amino resin yakazara methylated, ine boka rimwe chete rinoshanda: methoxy group, iro rakanyatsokodzera. Sezvo mwero we etherification usingakwanise kusvika 1:6 (yakakwirira) mukugadzirwa chaiko, iyo inonzi fully methylated amino resin inogara iine mamwe mapoka e imino ne hydroxymethyl.
Ngatitangei nekunzwisisa misimboti yema amino resins kuti tidzidze nezvehunhu hwawo:
Danho rekutanga mukugadzira resin nderekuita kuti melamine iite seformaldehyde kana paine chinhu chinoita kuti igadzire polyhydroxymethyl melamine. Maatomu ese ehydrogen ari patriazine ring anogona kushandurwa kuita mahydroxymethyl groups, asi muchokwadi, mamole maviri kusvika matanhatu eformaldehyde anopindira patriazine ring. Maatomu ehydrogen akashanda asina kugadziriswa anomiririrwa nemapoka eimino. Sezvatichaona gare gare, mapoka aya anoita basa rakakosha mukuita kwekuporesa kuburikidza nekuzvigadzirisa polymerization.
Polyhydroxymethyl melamine haina kugadzikana zvakanyanya uye ine kunyungudika kushoma muzvinonyungudutsa zvechinyakare. MaAmino resins anonyanya kushanda sezvinhu zvinobatanidza uye zvinopodza muzviputi. Kuti vagadzire chinhu chakakodzera chekubatanidza zviputi, boka rehydroxymethyl rinowanzo piswa nedoro repfupi kuti rideredze reactivity yaro uye rivandudze kuenderana kwaro nezvinhu zvinogadzira mafirimu uye zvinonyungudutsa zvealiphatic. Methanol nebutanol zvinowanzo shandiswa sezviputi zvipfupi. Nekudzora huwandu hwemethanol kana butanol inowedzerwa nezvimwe zvinhu, maamino resins ane mwero wakasiyana we etherification anogona kuwanikwa.
Nzvimbo dzakaita resolution ne formaldehyde (hydroxymethyl groups) chete ndidzo dzinogona kuvharwa ne alcohols; maatomu ehydrogen asina kuita resolution (imino groups) haaite resolution ne short-chain alcohols. Uyezve, resolution iyi inoratidza kuti ma group ese matanhatu e hydroxymethyl anoita resolution ne alcohols kuti aumbe hexaalkoxymethyl melamine, zvichireva kuti resolution ye hydroxymethyl group imwe kusvika kumatanhatu ine alcohols inogona kudzorwa. Ndosaka tiine mhando dzakasiyana dze amino resin.
Kuzvigadzirisa pachako maamino resins :
Huremu hwemaamino resins hunotsanangurwa nehuwandu hwekuzvinyungudutsa kanakubatanidzapakati pemapoka anoshanda (imino, hydroxymethyl, alkoxymethyl) patriazine ring uye melamine molecules. Mukushandiswa kwekupedzisira, mwero we cross-linking polymerization unokanganisa zvakanyanya huremu hwemaamino resin uye mashandiro efirimu rekuputira.
Kuzvigadzirisa kweamino resins kunogona kuitika nenzira inotevera:
Mufananidzo 3:
Kubatana kuri kuruboshwe kunoumba zambuko remethylene, ukuwo kudivi rekurudyi kunoumba zambuko remethylene ether. Kubatana kwemaamino resins kunowanzo ratidzwa sedanho repolymerization (DP): DP = huremu hwemorekuru / huremu hweringi yega yega yetriazine. Maamino resins ekutanga ainyanya kuzvigadzirisa, neDP > 3.0. Kufambira mberi kwetekinoroji kwakaita kuti zvikwanisike kuderedza kuungana kweamino resins dzakapedzwa. Parizvino, ma melamine resins anowanikwa kutengeswa ane maDP akaderera se1.1.
Kukanganiswa kukuru kweamino resin molecular weight kunoratidzwa mukupenya kwekuvhara. Melamine resins ine DP > 2.0 inofanira kusanganiswa ne solvent kusvika 50%–80% solids kuti iwane viscosity yakakodzera. Monomer-type melamine resins ine DP iri pakati pe1.1 ne1.5 inowanzo pihwa muchimiro che 100% solids inoshanda; zvimwe zvinonyungudutsa zvine simba guru paVOCs ye coating yakapedzwa. Kurema kweamino resins kunokanganisawo coating curing reaction uye firimu properties. Coating system inoshandisa high-DP amino resin ichasvika pa crosslinking density yakatarwa munguva pfupi pane coating system inoshandisa amino resin ine chimiro chimwe chete asi DP yakaderera. Nokudaro, coating ine high-DP crosslinking agents inoda catalyst shoma kana weak acid catalyst kuti iwane curving state yakafanana. Mhedzisiro yehuremu hwemamorekuru pafirimu properties inonyanya kuitika. Coatings dzakaporeswa ne high-DP amino resins dzine chikamu chepamusoro che amino-amino bonds uye mashoma amino-lacquer bonds. Rudzi urwu rwe network inobatanidza tambo inoumba coating ine kuoma kwakanaka asi inogona kuputsika. Izvi dzimwe nguva zvinogona kubhadharwa nekusarudza pendi resin inochinjika. Zvisinei, mashandisirwo anoda coating inochinjika zvakanyanya anowanzoda monomeric amino resins.
Mapolyester ane mapoka ecarboxyl anogona kusangana nemelamine-formaldehyde kugadzira machira epamusoro anobatsira ethermosetting ane hunhu hwakasiyana-siyana.
Mazhinji maresini emelamine-formaldehyde ane butylated anogona kushandiswa mukutengeserana, kunyanya nekuda kwekusiyana kwehuwandu hwekutanga hwepolymerization (huremu hwemolecular) uye chiyero chemapoka ealkoxy kune asina mapoka ehydroxymethyl uye amino hydrogens. Kusiyana uku kunokanganisa viscosity yemvura, kuenderana kwemelamine nepolyester, uye kumhanya kwekuporesa kweenamel. Maresini emelamine echinyakare, achibatana nemapoka ehydroxyl, anonyanya kubatanidzwa nepolyester molecules. Sezvo crosslinking reaction ichiitwa acid-catalyzed, pakupisa kuri pakati pe120°C ne150°C, maacid akasimba anowanzo kukanganisa crosslinking reaction yepolyester resins; zvisinei, mamwe mapolyester anoda imwe acid catalysis muasidhi asina simba kuti agadzirise enamel system.
Chiitiko chinotevera chiripo: Pamusoro pekuita kwekubatanidza kwemelamine-polyester, resin yemelamine-formaldehyde ine butylated inozvibatanidzawo. Kureva kuti, amino resin inozvibatanidza yoga kuti igadzire chimiro chenetiweki yemelamine. Kuita uku kunoitika panguva imwe chete nekuita kwemelamine-polyester uye kunokwikwidzana. Chikonzero chekuita uku ndechekuti, pamusoro pemapoka e-butoxy, resin yemelamine-formaldehyde ine butylated inewo mapoka e-hydrocarbon methyl akasununguka uye hydrogen kubva kumapoka e-imino, ese anogona kusangana. Kana amino resin yangosangana yoga, icharasikirwa nemamwe mabasa ayo.
Kunyange zvazvo kuzvibatanidza pachako kuchiwanzoita kuti machira acho ave akaomarara uye asakwanise kushandiswa nemakemikari, zvinoita kuti arasike zvakanyanya. Kuti varairidzi vepolyester varnish vawane kusimba kwakakwana...
Hexamethoxymethyl melamine (HMMM) i-amino resin ine hydroxymethyl uye yakazara methylated monomeric. Kufanana ne-butylated melamine-formaldehyde, inosangana ne-cross-linking reaction ne-hydroxyl groups ye polyester resin painodziiswa, zvichiita kuti ive solid isinganyorove. Chaizvoizvo, pasina acid catalyst, HMMM haizozvisanganisire yega kunyangwe kwenguva yakareba kana tembiricha yakawedzera. Zvisinei, HMMM yakawanda ichasangana ne-self-linking reaction pa150°C kana paine strong acid catalyst. Kusiyana neizvi, kunyangwe pasina strong acid, butylated melamine uye urea resins dzichasangana ne-self-linking reactions dzakasimba nekupisa kuri kuwedzera.
Kurapa kwekuita kwema amino resins:
Sezvo maamino resins achishandiswa kubatanidza mamorekuru makuru anogadzira firimu kuita network structure, co-condensation reaction yemaamino resins nemapendi resins inonyanya kufarirwa. Muenzaniso wakajairika i etherification (exchange) reaction.mapoka ehydroxyl pamaresini ependi uye mapoka ealkoxymethyl pamaresini emaamino.
Mumamiriro ezvinhu ekupisa uye acid catalysts (zvinowanzo shandiswa pakurapa), crosslinking inoitika nekukurumidza, ichibatanidza mapoka ese ehydroxyl aripo papendi. Kutaura zvazviri, sezvo chimiro che polymer network chichiumbwa, kuyerera kwe reactants kunoderera, zvichisiya mamwe mapoka e hydroxyl asina kugadziriswa. Kazhinji, kana amino resin yakawandisa iri mu coating zvichienzaniswa ne ideal ratio, mapoka e alkoxy asara anogona kutora chikamu mune mamwe maitiro kana kuramba asina kugadziriswa mu coating film. Sezvambotaurwa, amino resin anozvibatanidza nyore nyore uye anopindirana, zvichikonzera kuwedzera kwehuremu hwemamorekuru panguva yekugadzira. Maitiro aya anoitikawo panguva ye coating curing. Saka, pane kuva chinhu chisina kunaka, imwe nhanho ye self-crosslinking ye amino resin yakakosha kuti pave ne polymer matrix yakasimba, yakabatana zvakanaka. Mapoka ese matatu anoshanda e amino resin anotora chikamu mu self-crosslinking reactions, uye mu fully alkylated melamine resin coating coatings catalyzed ne strong acids, pane humbowo hwekuti maitiro aya anoitika mushure me ether exchange ne coating resin. Kana pasina ma catalysts ekunze kana ma weak acid catalysts, ma self-linking reactions aya anoitika zvakanyanya muma melamine resin systems ane high imino/kana hydroxymethyl functionality. Muzviitiko zvese izvi, self-polymerization reaction shoma yakakosha pakuumbwa kwe network structure yakanaka.
Panguva yekucheneswa kweamino resin yakasanganiswa, mamwe maitiro anoitika kubvisa formaldehyde uye hydrolysis. Kubviswa kweformaldehyde kunoitika nyore nyore pakupisa kwakajairika, inova ndiyo yega chikonzero chekuburitswa kweformaldehyde panguva yekucheneswa kweamino resin; imwe formaldehyde ifree formaldehyde.
Kana maamino resins akabatana kuti agadzire mafirimu uye agadzirise, mamwe maitiro ehydrolysis anoitika. Munguva iyi, mamwe mapoka ealkoxymethyl anoshandurwa kuita mapoka ehydroxymethyl. Hydrolysis yema melamine resins ane imino yakawanda kana hydroxymethyl inogona kukonzerwa nealkalis, uye inogona kutoitika zvishoma nezvishoma patembiricha yemukamuri. Izvi zvinoita kuti ma amino resins ave nyore kuzvibatanidza, zvichikonzera kuwedzera kwekunaka kwejira panguva yekuchengetwa. Kuti izvi zvisaitike, ma melamine resins ane methyl kana co-solvents anodzivirira alkali hydrolysis anogona kushandiswa muzviputiro zvemvura. Ma melamine resins ane alkylated anodzivirira alkali-catalyzed hydrolysis mumasisitimu ane mvura. Ma melamine resins ane alkylated uye chikamu chealkyled haadziviriri acid-catalyzed hydrolysis mumasisitimu ane mvura; saka, blocked acid catalyst inofanira kushandiswa musisitimu ine mvura.
Kana uchida kuziva zvakawandamumiririri wekubatanidzazvigadzirwa, inzwa wakasununguka kutibata.
Nguva yekutumira: Zvita-19-2025