Nchịkọta nke ngwa nkeihe ndị na-ejikọ amino resin
Isi ọrụ nke amino resins (melamine-formaldehyde, benzomelamine-formaldehyde, na urea-formaldehyde resins) na mkpuchi thermosetting bụ ijikọ mkpụrụ ndụ ihe nkiri bụ isi n'ime usoro netwọk atọ site na mmeghachi omume kemịkalụ. A na-enweta nhazi netwọk a site na mmeghachi omume nke mkpụrụ ndụ amino resin na otu ọrụ na mkpụrụ ndụ ihe nkiri na-akpụ ihe nkiri, yana n'otu oge site na njikọta polymerization na mkpụrụ ndụ amino resin ndị ọzọ. Amino resins na-emeghachi omume ngwa ngwa na polymers nwere otu hydroxyl mbụ na nke abụọ, otu carboxyl, na otu amide; ya mere, a na-ejikarị amino resins eme ihe na sistemụ agba dabere na acrylic, polyester, alkyd, ma ọ bụ epoxy resins.
A na-ejikwa resin amino na sistemụ polyurethane dị ka ihe mgbakwunye mkpuchi iji melite arụmọrụ zuru oke nke mkpuchi maka ụfọdụ ngwa.
Ụkpụrụ nke amino resins:
Mkpa amino resin dị na varnish ime achịcha karịrị oke ha na mkpuchi. Ịghọta otu esi eji ihe kemịkalụ nke amino resin eme ihe n'imepụta nhazi mkpuchi na-aghọwanye ihe dị mkpa. Dịka ọmụmaatụ,Ọ bụrụ na ndị na-emepụta ihe mkpuchi enweghị afọ ojuju na ụfọdụ ihe onwunwe nke ihe mkpuchi ahụ, ha nwere ike ịgbanwe ha site na iji usoro ndị a:
1. Mmezi ma ọ bụ nhọpụta ọzọ nke resin na-akpụ ihe nkiri ahụ n'onwe ya;
2. Nhọrọ nke amino resins (methyl etherification ma ọ bụ butyl etherification, na nhọrọ nke ogo etherification, wdg);
3. Oke nke resin na-akpụ ihe nkiri na amino resin.
4. Nhọrọ nke onye na-eme ka ihe dị mkpa (ma ọ ga-agbakwunye ya ma ọ bụ na ọ gaghị etinye, na ego ole a ga-agbakwunye).
Isi ihe anọ niile dị n'elu, ewezuga nke mbụ,ihe jikọrọ ya na amino resins. Njirimara nke amino resins dabere na otu ọrụ ha na ọrụ ha.; ya mere, ịghọta usoro nke amino resin dị oke mkpa. Agbanyeghị, tupu ịghọta amino resins, ọ dị mkpa inwe nghọta bụ isi nke resin ndị a na-eji na njikọta ha.
Dịka e kwuru na mbụ, amino resins na-abụkarị ihe na-edozi ahụ.A na-eji ya na alkyd resins, acrylic resins, polyester resins, na epoxy resins. A na-esi na polyols na polyacid resins emepụta resins alkyd site na esterification. N'oge mmepụta, mmanya na-aba n'anya na-abụkarị ihe karịrị akarị; ụfọdụ otu carboxyl nke polyacids nwere ike ọ gaghị emeghachi omume kpamkpam, na-eme ka resin alkyd nwere ụfọdụ otu carboxyl na hydroxyl. A na-ejikarị uru acid na uru hydroxyl mara ọnụọgụgụ milligrams nke KOH achọrọ iji mee ka 1g nke resin siri ike ghara ịdị irè site na titration na KOH. Uru Hydroxyl na-ezo aka na ọnụọgụgụ milligrams nke KOH achọrọ iji mee ka otu OH ghara ịdị irè kpamkpam na 1g nke resin siri ike site na titration na KOH. N'otu aka ahụ, resins polyester, resin acrylic, na amino resins nwekwara ụfọdụ otu carboxyl na hydroxyl. Ihe dị iche dị na ihe eji emepụta resins; dịka ọmụmaatụ, otu carboxyl dị na acrylic resins sitere na acrylic acid, otu hydroxyl sikwa na hydroxyacrylic acid. Ọnụọgụ nke otu carboxyl na hydroxyl dị na amino resin dịkwa iche. Uru acid, uru hydroxyl, na viscosity bụ ihe ngosi dị mkpa nke resin, na-emetụta arụmọrụ ha ozugbo.
Ka anyị laghachi n'isiokwu gbasara amino resins, ka anyị buru ụzọ leba anya n'otú ha si arụ ọrụ:
Foto nke 1:
Foto nke 2
Foto nke 1 na-egosi otu amino resin nke nwere akụkụ alkylated nke nwere otu alkoxy, imino, na hydroxymethyl. Ọ bụrụ na anyị ewere mgbanaka nwere akụkụ isii nke atọm carbon na nitrogen mepụtara dị ka ọkpụkpụ, a pụrụ ịkọwa alaka ma ọ bụ ihe owuwu sitere na ya n'ụzọ ihe atụ dị ka ndị nwere isi atọ na ogwe aka isii. Ọtụtụ mgbanwe dị iche iche na njirimara nke amino resin bụ kpọmkwem n'ihi ọdịiche dị na "ogwe aka" isii a na nhazi na njikọta ha dị mgbagwoju anya.
Foto nke 2 na-egosi nhazi HMMM nke nwere methylation zuru oke, ya bụ, amino resin zuru oke, nwere naanị otu ọrụ: otu methoxy, nke a na-eme ka ọ dị mma. Ebe ọ bụ na ọkwa etherification enweghị ike iru 1:6 (nke kachasị elu) na mmepụta n'ezie, ihe a na-akpọ amino resin zuru oke ga-enwe ụfọdụ otu imino na hydroxymethyl mgbe niile.
Ka anyị malite site n'ịghọta ụkpụrụ nke amino resins iji mụta maka ihe onwunwe ha:
Nzọụkwụ mbụ n'ịmepụta resin ahụ bụ imeghachi melamine na formaldehyde n'ihu ihe na-akpali akpali iji mepụta polyhydroxymethyl melamine. Enwere ike ịgbanwe atọm hydrogen niile na-arụ ọrụ na mgbanaka triazine ka ọ bụrụ otu hydroxymethyl, mana n'eziokwu, ọ bụ mole 2 ruo 6 nke formaldehyde na-emeghachi omume na mgbanaka triazine. Atọm hydrogen na-arụ ọrụ ndị fọdụrụ na-anaghị emeghachi omume ka otu imino na-anọchi anya ya. Dịka anyị ga-ahụ ma emechaa, otu ndị a na-arụ ọrụ dị mkpa na usoro ọgwụgwọ site na polymerization onwe-condensation.
Polyhydroxymethyl melamine anaghị akwụsi ike nke ukwuu ma nwee obere mgbaze na ihe mgbaze mkpuchi nkịtị. Amino resins na-arụ ọrụ dị ka ihe njikọ na ọgwụgwọ na mkpuchi. Iji mepụta ihe njikọ kwesịrị ekwesị maka mkpuchi, a na-ejikarị mmanya mkpụmkpụ eme ka otu hydroxymethyl ahụ dị n'ime ka ọ dị mma iji belata mmeghachi omume ya ma melite ndakọrịta ya na ihe ndị na-emepụta ihe nkiri ọdịnala na ihe mgbaze aliphatic. A na-ejikarị methanol na butanol eme ihe dị ka mmanya mkpụmkpụ. Site na ijikwa oke methanol ma ọ bụ butanol agbakwunyere na ọnọdụ ndị ọzọ, enwere ike nweta amino resins nwere ọkwa dị iche iche nke etherification.
Naanị ebe ndị meghachiri omume na formaldehyde (òtù hydroxymethyl) ka a pụrụ itinye mmanya na-aba n'anya; atọm hydrogen ndị na-anaghị emeghachi omume (òtù imino) anaghị emeghachi omume na mmanya mkpụmkpụ. Ọzọkwa, mmeghachi omume a na-egosi na otu hydroxymethyl isii niile na-emeghachi omume na mmanya iji mepụta hexaalkoxymethyl melamine, nke pụtara na enwere ike ijikwa mmeghachi omume nke otu hydroxymethyl ruo isii na mmanya na-aba n'anya. Ọ bụ ya mere anyị ji nwee ụdị amino resin dị iche iche.
Nhazi onwe-onwe nke amino resins :
A na-ekpebi oke molekul nke amino resins site na ogo nke njikọta onwe ya ma ọ bụnjikọ dị n'etitin'etiti otu ọrụ (imino, hydroxymethyl, alkoxymethyl) na mgbanaka triazine na molekul melamine. Na njedebe ojiji, ogo nke njikọta polymerization na-emetụta oke molekul nke amino resin na arụmọrụ nke ihe nkiri mkpuchi ahụ.
Mmeghachi omume nke amino resins nwere ike ime site na usoro ndị a:
Foto nke 3:
Mmeghachi omume dị n'aka ekpe na-emepụta àkwà mmiri methylene, ebe mmeghachi omume dị n'aka nri na-emepụta àkwà mmiri methylene ether. A na-egosipụtakarị ogo njikọta na amino resins dị ka ogo polymerization (DP): DP = ibu molekul / ibu nke mgbanaka triazine ọ bụla. Amino resins mbụ na-abụkarị polymerizing onwe ya, yana DP > 3.0. Mmepe teknụzụ emeela ka o kwe omume ibelata mkpokọta onwe na amino resin emechara. Ugbu a, resin melamine dị n'ahịa nwere DP dị ala dị ka 1.1.
Mmetụta dị ukwuu nke ibu amino resin na-apụta ìhè na viscosity mkpuchi. A ga-agwakọta resin Melamine nwere DP > 2.0 na ihe mgbaze ruo 50%–80% siri ike iji nweta viscosity dabara adaba. A na-enye resin melamine ụdị Monomer nwere DP dị n'etiti 1.1 na 1.5 n'ụdị siri ike dị irè 100%; ihe mgbaze ndị ọzọ nwere mmetụta dị ukwuu na VOC nke mkpuchi emechara. Ibu molekul nke amino resin na-emetụtakwa mmeghachi omume ọgwụgwọ mkpuchi na ihe nkiri. Sistemụ mkpuchi nke na-eji amino resin dị elu ga-eru njupụta njikọta akọwapụtara n'oge dị mkpirikpi karịa sistemụ mkpuchi na-eji amino resin nwere otu nhazi mana DP dị ala. Ya mere, mkpuchi nwere ihe nnọchite anya njikọta dị elu-DP chọrọ obere ihe mkpali ma ọ bụ ihe na-akpali acid dị ala iji nweta otu ọnọdụ ọgwụgwọ. Mmetụta nke ibu molekul na ihe onwunwe fim dị na oke mgbanwe. Mkpuchi ejiri amino resin dị elu-DP gwọọ nwere pasent dị elu nke njikọ amino-amino na obere njikọ amino-lacquer. Ụdị nhazi netwọk njikọ a na-eme ka mkpuchi sie ike nke ọma mana ọ nwere ike imebi emebi. Mgbe ụfọdụ, a pụrụ ịkwụghachi nke a site n'ịhọrọ resin agba na-agbanwe agbanwe karị. Agbanyeghị, ngwa ndị chọrọ mkpuchi dị oke nro na-achọkarị resin amino monomeric.
Polyesters nwere otu carboxyl nwere ike imeghachi omume na melamine-formaldehyde iji mepụta mkpuchi elu thermosetting bara uru nke nwere ọtụtụ ihe anụ ahụ.
Ọtụtụ resin melamine-formaldehyde butylated dị irè n'ahịa, nke bụ isi n'ihi ọdịiche dị na ọkwa mbụ nke polymerization (ibu molekul) na oke nke otu alkoxy na ndị na-enweghị otu hydroxymethyl na amino hydrogen. Ọdịiche ndị a na-emetụta viscosity mmiri mmiri, ndakọrịta nke melamine na polyester, na ọsọ ọgwụgwọ nke enamel. Resin melamine ọdịnala, nke na-emeghachi omume na otu hydroxyl n'akụkụ, na-ejikọkarị na molekul polyester. Ebe ọ bụ na mmeghachi omume njikọta na-eme ka acid dị, na okpomọkụ dị n'etiti 120°C na 150°C, asịd siri ike na-emetụtakarị mmeghachi omume njikọta nke resin polyester; agbanyeghị, ụfọdụ polyester chọrọ mgbakwunye acid catalysis na asịd ndị na-adịghị ike iji gwọọ sistemụ enamel.
Ihe na-eso nke a dị adị: Na mgbakwunye na mmeghachi omume njikọta nke melamine-polyester, butylated melamine-formaldehyde resin na-enwetakwa mmeghachi omume njikọta onwe. Ya bụ, amino resin na-abanye njikọ onwe ya iji mepụta nhazi netwọk melamine. Mmeghachi omume a na-eme n'otu oge na mmeghachi omume melamine-polyester ma bụrụ mmeghachi omume asọmpi. Ihe kpatara mmeghachi omume a bụ na, na mgbakwunye na otu butoxy, butylated melamine-formaldehyde resin nwekwara otu hydrocarbon methyl efu na hydrogen sitere na otu imino, nke niile nwere ike imeghachi omume na ibe ha. Ozugbo amino resin na-abanye njikọ onwe ya, ọ ga-efunahụ ụfọdụ ọrụ ya.
Ọ bụ ezie na njikọta onwe onye na-enye mkpuchi ike na iguzogide kemịkalụ ka ukwuu, ọ na-eme ka ọ ghara ịdị ike nke ukwuu. Iji nweta ike zuru oke na varnish polyester...
Hexamethoxymethyl melamine (HMMM) bụ hydroxymethylated zuru oke ma nwee methylated zuru oke. Dị ka butylated melamine-formaldehyde, ọ na-enweta mmeghachi omume njikọ cross-linked na hydroxyl otu nke polyester resin mgbe a na-ekpo ọkụ, na-emepụta ihe siri ike na-adịghị eme ka ọ dị nro. N'ụzọ bụ isi, na-enweghị ihe na-akpali acid, HMM agaghị enweta njikọ onwe ya ọbụlagodi na ogologo oge ma ọ bụ okpomọkụ dị elu. Agbanyeghị, nnukwu HMM ga-enweta mmeghachi omume njikọ onwe ya na 150°C n'ihu ihe na-akpali acid siri ike. N'aka nke ọzọ, ọbụlagodi na enweghị acid siri ike, melamine na urea resins butylated ga-enweta mmeghachi omume njikọ onwe onye siri ike na okpomọkụ na-abawanye.
Mmeghachi omume nke amino resins:
Ebe ọ bụ na a na-eji amino resin ejikọta mkpụrụ ndụ ihe ndị bụ isi na-emepụta ihe nkiri n'ime usoro netwọk, mmeghachi omume njikọta nke amino resins na resin agba dị oke mma. Ihe atụ a na-ahụkarị bụ mmeghachi omume etherification (mgbanwe).nke otu hydroxyl na resin agba na otu alkoxymethyl na resin amino.
N'okpuru ọnọdụ nke ihe na-akpali okpomọkụ na acid (nke na-abụkarị ọnọdụ ọgwụgwọ), njikọta na-eme ngwa ngwa, na-ejikọ otu hydroxyl niile dị na agba ahụ. N'ezie, ka nhazi netwọk polymer na-etolite, mmụba nke ihe ndị na-emeghachi omume na-ebelata, na-ahapụ ụfọdụ otu hydroxyl na-anaghị emeghachi omume. N'ozuzu, mgbe oke amino resin dị na mkpuchi ahụ ma e jiri ya tụnyere oke zuru oke, otu alkoxy fọdụrụ nwere ike isonye na mmeghachi omume ndị ọzọ ma ọ bụ ghara imeghachi omume na ihe nkiri mkpuchi ahụ. Dịka ekwuru na mbụ, amino resins na-ejikọ onwe ha ngwa ngwa ma na-emeghachi omume na ibe ha, na-ebute mmụba na ibu molekul n'oge mmepụta. Mmeghachi omume ndị a na-emekwa n'oge mkpuchi mkpuchi. Ya mere, kama ịbụ ihe na-adịghị mma, ụfọdụ oke njikọ nke amino resins dị mkpa iji nweta matriks polymer siri ike nke na-adịgide adịgide. Otu atọ niile na-arụ ọrụ nke amino resins na-esonye na mmeghachi omume njikọ onwe onye, na mkpuchi melamine resin alkylated zuru oke nke acid siri ike na-eme ka ọ dị, enwere ihe akaebe na mmeghachi omume ndị a na-eme mgbe mgbanwe ether na resin mkpuchi ahụ gasịrị. Ọ bụrụ na enweghị ihe mkpali mpụga ma ọ bụ ihe mkpali acid na-adịghị ike, mmeghachi omume njikọ onwe onye ndị a na-eme n'ụzọ dị ukwuu na sistemụ resin melamine nwere ọrụ imino/ma ọ bụ hydroxymethyl dị elu. N'ọnọdụ abụọ a, obere mmeghachi omume onwe-polymerization dị oke mkpa maka ịmepụta ezigbo nhazi netwọk.
N'oge a na-agwọ ihe mkpuchi amino resin, mmeghachi omume ndị ọzọ na-eme bụ iwepụ formaldehyde na hydrolysis. Mwepụ formaldehyde na-eme ngwa ngwa n'oge okpomọkụ nkịtị, nke fọrọ nke nta ka ọ bụrụ naanị ihe kpatara ntọhapụ nke formaldehyde n'oge a na-agwọ amino resins; formaldehyde nke ọzọ bụ formaldehyde efu.
Mgbe amino resins na-ejikọta iji mepụta ihe nkiri ma gwọọ, ụfọdụ mmeghachi omume hydrolysis na-eme. N'oge usoro a, a na-agbanwe ụfọdụ otu alkoxymethyl ka ọ bụrụ otu hydroxymethyl. Alkalis nwere ike ime ka hydrolysis nke melamine resins nwere nnukwu imino ma ọ bụ hydroxymethyl dị elu, ọ pụkwara ime nwayọ nwayọ na okpomọkụ ụlọ. Nke a na-eme ka amino resins dịkwuo mfe ijikọ onwe ya, na-eduga na mmụba nke viscosity nke mkpuchi ahụ n'oge nchekwa. Iji zere nke a, enwere ike iji resin melamine zuru oke ma ọ bụ co-solvents ndị na-eguzogide alkali hydrolysis na mkpuchi mmiri. Resin melamine zuru oke na-eguzogide hydrolysis alkali-catalyzed na sistemụ mmiri. Resin melamine zuru oke na nke alkylated anaghị eguzogide hydrolysis acid-catalyzed na sistemụ mmiri; ya mere, a ga-eji ihe na-akpali acid egbochiri na sistemụ mmiri.
Ọ bụrụ na ịchọrọ ịmatakwuonye na-ejikọ njikọngwaahịa, nweere onwe gị ịkpọtụrụ anyị.
Oge ozi: Disemba-19-2025