Kakaretso ea ts'ebeliso eali-amino resin crosslinking agents
Karolo e ka sehloohong ea li-amino resin (melamine-formaldehyde, benzomelamine-formaldehyde, le li-urea-formaldehyde) ho li-coating tsa thermosetting ke ho hokahanya limolek'hule tse kholo tsa thepa e etsang filimi le sebopeho sa marang-rang a mahlakore a mararo ka liketso tsa lik'hemik'hale. Sebopeho sena sa marang-rang se fumanoa ka karabelo ea limolek'hule tsa resin ea amino le lihlopha tse sebetsang limolek'huleng tsa thepa e etsang filimi, le ka nako e le 'ngoe ka polymerization ea condensation le limolek'hule tse ling tsa resin ea amino. Li-amino resin li arabela habonolo le li-polymer tse nang le lihlopha tsa hydroxyl tsa mantlha le tsa bobeli, lihlopha tsa carboxyl, le lihlopha tsa amide; ka hona, li-amino resin li sebelisoa hangata lits'ebetsong tsa pente tse thehiloeng ho li-acrylic, polyester, alkyd, kapa epoxy resin.
Li-resin tsa amino li boetse li sebelisoa lits'ebetsong tsa polyurethane e le lisebelisoa tsa ho koahela ho ntlafatsa ts'ebetso eohle ea ho koahela bakeng sa lits'ebetso tse itseng.
Molao-motheo oa li-amino resins:
Bohlokoa ba li-amino resins ka har'a li-varnish tsa ho baka bo feta haholo tekanyo ea tsona ka har'a li-coat. Ho utloisisa mokhoa oa ho sebelisa lik'hemik'hale tsa li-amino resins moralong oa ho etsa li-coat ho ntse ho ba bohlokoa le ho feta. Mohlala,Haeba di-formulator tsa ho roala di sa kgotsofala ka thepa e itseng ya filimi ya ho roala, di ka di lokisa di sebedisa mekgwa e latelang:
1. Ntlafatso kapa khetho e ncha ea resine e etsang filimi ka boeona;
2. Khetho ea li-amino resins (methyl etherification kapa butyl etherification, le khetho ea tekanyo ea etherification, jj.);
3. Karolelano ea resine e etsang filimi ho resine ea amino.
4. Khetho ea Catalyst (hore na u e eketsa kapa che, le hore na u e eketsa hakae).
Lintlha tsohle tse 'ne tse ka holimo, ntle le ea pele,li amana le li-amino resins. Thepa ea li-amino resins e itšetlehile ka lihlopha tsa tsona tse sebetsang le mosebetsi oa tsona.; ka hona, ho utloisisa sebopeho sa li-amino resins ho bohlokoa. Leha ho le joalo, pele u utloisisa li-amino resins, ho bohlokoa ho ba le kutloisiso ea motheo ea li-amino resins tse sebelisoang hammoho le tsona.
Joalokaha ho boletsoe pejana, li-amino resins ke tsona tse ka sehloohonge sebelisoa hammoho le li-resin tsa alkyd, li-resin tsa acrylic, li-resin tsa polyester, le li-resin tsa epoxy.. Li-resin tsa alkyd li hlahisoa haholo-holo ho tsoa ho li-polyol le li-resin tsa polyacid ka ho esterification. Nakong ea tlhahiso, alcohols hangata li ngata haholo; lihlopha tse ling tsa carboxyl tsa li-polyacid li kanna tsa se arabele ka botlalo, e leng se fellang ka li-resin tsa alkyd tse nang le bongata bo itseng ba lihlopha tsa carboxyl le hydroxyl. Bongata ba lihlopha tsa carboxyl le hydroxyl hangata bo khetholloa ka boleng ba asiti le boleng ba hydroxyl. Boleng ba asiti bo bolela palo ea li-milligram tsa KOH tse hlokahalang ho fokotsa 1g ea resin e tiileng ka ho titration ka KOH. Boleng ba Hydroxyl bo bolela palo ea li-milligram tsa KOH tse hlokahalang ho felisa ka botlalo lihlopha tsa OH ho 1g ea resin e tiileng ka ho titration ka KOH. Ka ho tšoanang, li-resin tsa polyester, li-resin tsa acrylic, le li-resin tsa amino le tsona li na le bongata bo itseng ba lihlopha tsa carboxyl le hydroxyl. Phapang e ho thepa e tala e sebelisoang ho kopanya li-resin; mohlala, lihlopha tsa carboxyl li-resin tsa acrylic li tsoa ho acrylic acid, 'me lihlopha tsa hydroxyl li tsoa ho hydroxacrylic acid. Bongata ba lihlopha tsa carboxyl le hydroxyl ka har'a li-amino resins le tsona lia fapana. Boleng ba asiti, boleng ba hydroxyl, le ho teteana kaofela ke matšoao a bohlokoa a li-resins, tse amang ka kotloloho ts'ebetso ea tsona.
Ha re kgutlela tabeng ya di-amino resins, a re qaleng ka ho sheba sebopeho sa tsona:
Setšoantšo sa 1:
Setšoantšo sa 2
Setšoantšo sa 1 se bontša resine ea amino e nang le alkylated ka karolo e itseng e nang le lihlopha tsa alkoxy, imino, le hydroxymethyl. Haeba re nahana ka lesale la litho tse tšeletseng le entsoeng ke liathomo tsa carbon le naetrojene e le masapo, makala kapa meaho e nkiloeng ho lona e ka hlalosoa ka tsela ea tšoantšetso e le e nang le lihlooho tse tharo le matsoho a tšeletseng. Liphapang tse ngata tsa thepa ea resine ea amino li bakoa hantle ke liphapang tse "matsohong" ana a tšeletseng le litlhophiso tsa 'ona tse rarahaneng le metsoako.
Setšoantšo sa 2 se bonts'a sebopeho sa HMMM se lekanang haholo, ke hore, resine ea amino e nang le methylation e felletseng, e nang le sehlopha se le seng feela se sebetsang: sehlopha sa methoxy, se loketseng. Kaha tekanyo ea etherification e ke ke ea fihla ho 1:6 (e phahameng ka ho fetisisa) tlhahisong ea 'nete, resine ea amino e bitsoang methylated e felletseng e tla lula e na le lihlopha tse ling tsa imino le hydroxymethyl.
A re qaleng ka ho utloisisa melao-motheo ea li-amino resins ho ithuta ka thepa ea tsona:
Mohato oa pele oa ho kopanya resin ke ho arabela melamine le formaldehyde boteng ba catalyst ho theha polyhydroxymethyl melamine. Liathomo tsohle tsa haedrojene tse sebetsang tse lesale la triazine li ka fetoloa lihlopha tsa hydroxymethyl, empa ha e le hantle, ke limolek'hule tse 2 ho isa ho tse 6 tsa formaldehyde tse arabelang lesale la triazine. Liathomo tse setseng tsa haedrojene tse sebetsang tse sa arajoang li emeloa ke lihlopha tsa imino. Joalokaha re tla bona hamorao, lihlopha tsena li bapala karolo ea bohlokoa ts'ebetsong ea ho folisa ka polymerization ea ho itšehla thajana.
Polyhydroxymethyl melamine ha e tsitse haholo 'me e na le ho qhibiliha ho fokolang lithapong tse tloaelehileng tsa ho roala. Li-resin tsa amino li sebetsa haholo-holo e le li-agent tse kopanyang le tse folisang lithapong. Ho theha moemeli ea loketseng oa ho kopanya bakeng sa lithapo, sehlopha sa hydroxymethyl hangata se tšeloa ka joala bo khutšoanyane ho fokotsa ts'ebetso ea sona le ho ntlafatsa ho lumellana ha sona le thepa e tloaelehileng ea ho etsa filimi le lithapo tsa aliphatic. Methanol le butanol li sebelisoa hangata e le li-alcohol tse khutšoanyane. Ka ho laola bongata ba methanol kapa butanol e ekelitsoeng le maemo a mang, li-resin tsa amino tse nang le maemo a fapaneng a etherification li ka fumanoa.
Ke libaka tse arabelitseng formaldehyde (lihlopha tsa hydroxymethyl) feela tse ka koaloang ka alcohols; liathomo tsa hydrogen tse sa arabeloang (lihlopha tsa imino) ha li arabe ka alcohols tse khutšoane. Ho feta moo, karabelo ena e bontša hore lihlopha tsohle tse tšeletseng tsa hydroxymethyl li arabelletsa le alcohols ho theha hexaalkoxymethyl melamine, ho bolelang hore karabelo ea sehlopha se le seng ho isa ho tse tšeletseng tsa hydroxymethyl ka alcohols e ka laoloa. Ke ka lebaka lena re nang le mefuta e fapaneng ea li-amino resin.
Ho iketsetsa polymerization ea li-amino resins :
Boima ba limolek'hule tsa li-amino resins bo khethoa ke tekanyo ea ho iponahatsa kapaho hokahanya ka tsela e fapanengpakeng tsa lihlopha tse sebetsang (imino, hydroxymethyl, alkoxymethyl) holim'a lesale la triazine le limolek'hule tsa melamine. Litšebelisong tsa ho qetela, tekanyo ea polymerization e kopanyang e ama haholo boima ba limolek'hule tsa resin ea amino le ts'ebetso ea filimi e koahelang.
Karabelo ea ho itšehla thajana ha li-amino resins e ka hlaha ka tsela e latelang:
Setšoantšo sa 3:
Karabelo ka letsohong le letšehali e etsa borokho ba methylene, ha karabelo ka letsohong le letona e etsa borokho ba methylene ether. Tekanyo ea ho hokahanya li-amino resins hangata e hlahisoa e le tekanyo ea polymerization (DP): DP = boima ba limolek'hule / boima ba lesale le leng le le leng la triazine. Li-amino resins tsa pele li ne li iketsa polymer, 'me DP e le > 3.0. Tsoelo-pele ea theknoloji e entse hore ho khonehe ho fokotsa ho iketsa polymer ho li-amino resins tse felileng. Hona joale, li-melamine resins tse fumanehang khoebong li na le li-DP tse tlase ho 1.1.
Tšusumetso e kholo ea boima ba limolek'hule tsa amino resin e bonahala ka har'a viscosity ea ho koahela. Li-resine tsa Melamine tse nang le DP > 2.0 li tlameha ho hlapolloa ka solvent ho ea ho 50%–80% ea lintho tse tiileng ho fihlela viscosity e sebetsang. Li-resine tsa melamine tsa mofuta oa monomer tse nang le DP pakeng tsa 1.1 le 1.5 hangata li fanoa ka foromo ea lintho tse tiileng tse sebetsang ka 100%; lintho tse ling tse qhibilihang li na le tšusumetso e kholo ho VOCs ea seaparo se felileng. Boima ba limolek'hule tsa li-resine tsa amino bo boetse bo ama karabelo ea ho phekola le thepa ea filimi. Sistimi ea ho koahela e sebelisang resine ea amino e nang le DP e phahameng e tla fihlela bongata bo boletsoeng ba ho kopanya ka nako e khuts'oane ho feta sistimi ea ho koahela e sebelisang resine ea amino e nang le sebopeho se tšoanang empa e le DP e tlase. Ka hona, liaparo tse nang le li-agent tse kopanyang tse nang le DP e phahameng li hloka catalyst e nyane kapa catalyst e fokolang ea asiti ho fihlela boemo bo tšoanang ba ho phekola. Tšusumetso ea boima ba limolek'hule holim'a thepa ea filimi e maemong a ho tenyetseha haholo. Li-coat tse phekoloang ka li-resine tsa amino tse nang le DP e phahameng li na le peresente e phahameng ea litlamo tsa amino-amino le litlamo tse fokolang tsa amino-lacquer. Mofuta ona wa sebopeho sa marangrang a hokelang o etsa lesela le nang le thata e ntle empa le ka ba le robehang habonolo. Sena ka linako tse ling se ka lefelloa ka ho khetha resin ea pente e tenyetsehang haholoanyane. Leha ho le joalo, lits'ebetso tse hlokang lesela le tenyetsehang haholo hangata li hloka li-amino resins tse monomeric.
Li-polyester tse nang le lihlopha tsa carboxyl li ka arabela le melamine-formaldehyde ho hlahisa lipente tse molemo tsa thermosetting holim'a metsi tse nang le mefuta e mengata ea thepa ea 'mele.
Li-resin tse ngata tsa melamine-formaldehyde tse nang le butyl li ka sebelisoa khoebong, haholo-holo ka lebaka la liphapang tsa tekanyo ea pele ea polymerization (boima ba limolek'hule) le karolelano ea lihlopha tsa alkoxy ho tse se nang lihlopha tsa hydroxymethyl le li-amino hydrogen. Liphapang tsena li ama viscosity ea metsi, ho lumellana ha melamine le polyester, le lebelo la ho fola ha enamel. Li-resin tsa melamine tsa setso, tse arabelang le lihlopha tsa hydroxyl tse lehlakoreng, haholo-holo li hokahane le limolek'hule tsa polyester. Kaha karabelo ea ho kopanya e bakoa ke acid-catalyzed, mochesong oa ho kopanya o pakeng tsa 120°C le 150°C, li-acid tse matla hangata li ama karabelo ea ho kopanya ea li-resin tsa polyester; leha ho le joalo, li-polyester tse ling li hloka catalysis e eketsehileng ea acid ka li-acid tse fokolang haholo ho phekola tsamaiso ea enamel.
Ketsahalo e latelang e teng: Ntle le karabelo ea ho kopanya melamine-polyester, resin ea melamine-formaldehyde e nang le butyl e boetse e feta karabelong ea ho iketsa. Ke hore, resin ea amino e feta ho iketsa ho kopanya ho etsa sebopeho sa marang-rang a melamine. Karabelo ena e etsahala ka nako e le 'ngoe le karabelo ea melamine-polyester 'me ke karabelo e qothisanang lehlokoa. Lebaka la karabelo ena ke hore, ntle le lihlopha tsa butoxy, resin ea melamine-formaldehyde e nang le butyl e boetse e na le lihlopha tsa methyl tsa hydrocarbon tse lokolohileng le hydrogen tse tsoang lihlopheng tsa imino, tseo kaofela li ka arabelang. Hang ha resin ea amino e feta ho iketsa ho kopanya, e tla lahleheloa ke mesebetsi e meng ea eona.
Leha ho ikopanya ka bohona hangata ho etsa hore masela a thatafale le ho hanyetsa lik'hemik'hale, ho fella ka tahlehelo e kholo ea ho tenyetseha. Ho fihlela ho tenyetseha ho lekaneng ka li-varnish tsa polyester...
Hexamethoxymethyl melamine (HMMM) ke resin ea monomeric e nang le hydroxymethyl e felletseng le methylated ka botlalo. Ho tšoana le melamine-formaldehyde e nang le butyl, e feta karabelong ea ho hokahanya le lihlopha tsa hydroxyl tsa resin ea polyester ha e futhumatsoa, e etsa solid e sa nolofatseng. Ha e le hantle, ntle le catalyst ea asiti, HMMM e ke ke ea feta ho ikopanya le eona leha e nka nako e telele kapa mocheso o eketsehileng. Leha ho le joalo, HMMM e ngata e tla feta karabelong ea ho ikopanya le eona ho 150°C ha ho na catalyst ea asiti e matla. Ka lehlakoreng le leng, esita le ha ho se na asiti e matla, melamine e tloaelehileng e nang le butyl le resin ea urea li tla feta ho kopana le mocheso o ntseng o eketseha.
Karabelo ea ho folisa ea li-amino resins:
Kaha li-amino resins li sebelisoa ho hokahanya limolek'hule tse kholo tsa thepa e etsang filimi le sebopeho sa marang-rang, karabelo ea condensation ea li-amino resins le li-pente resins e khahla haholo. Mohlala o tloaelehileng ke karabelo ea etherification (exchange)ea lihlopha tsa hydroxyl holim'a li-resin tsa pente le lihlopha tsa alkoxymethyl holim'a li-resin tsa amino.
Tlas'a maemo a mocheso le li-catalyst tsa asiti (hangata maemo a ho folisa), ho hokahana ho etsahala ka potlako, ho hokahanya lihlopha tsohle tsa hydroxyl tse fumanehang penteng. Ha e le hantle, ha sebopeho sa marang-rang a polymer se thehoa, ho phalla ha li-reactants hoa fokotseha, ho siea lihlopha tse ling tsa hydroxyl li sa arabeloe. Ka kakaretso, ha ho na le resin e ngata ea amino e teng ka har'a sekoahelo ha ho bapisoa le karolelano e loketseng, lihlopha tse setseng tsa alkoxy li ka nka karolo liketsong tse ling kapa tsa lula li sa arabeloe filiming ea sekoahelo. Joalokaha ho boletsoe pejana, li-resin tsa amino lia its'oara habonolo 'me lia arabelana, e leng se fellang ka keketseho ea boima ba limolek'hule nakong ea tlhahiso. Litšebetso tsena li boetse li etsahala nakong ea ho koahela sekoahelo. Kahoo, ho e-na le ho ba ntlha e mpe, tekanyo e itseng ea ho its'oara ha li-resin tsa amino e bohlokoa bakeng sa ho fumana matrix ea polymer e tšoarellang hantle, e pakiloeng ka thata. Lihlopha tsohle tse tharo tse sebetsang tsa li-resin tsa amino li nka karolo liketsong tsa ho its'oara, 'me ka li-coat tsa melamine resin tse nang le alkylated ka botlalo tse susumetsoang ke li-acid tse matla, ho na le bopaki ba hore liketso tsena li etsahala kamora phapanyetsano ea ether le resin ea sekoahelo. Ha ho se na di-catalyst tsa kantle kapa di-catalyst tse fokolang tsa asiti, di-reaction tsena tse iketsang di etsahala ka tekanyo e kgolo le ho feta ditsamaisong tsa melamine resin tse nang le tshebetso e phahameng ya imino/kapa hydroxymethyl. Maemong ana ka bobedi, karabelo e nyane ya self-polymerization e bohlokwa bakeng sa ho thehwa ha sebopeho se setle sa marangrang.
Nakong ea ho phekoloa ha li-coat tse kopantsoeng tsa amino resin, liketso tse ling tse hlahang ke ho tlosoa ha formaldehyde le hydrolysis. Ho tlosoa ha formaldehyde ho etsahala habonolo mochesong o tloaelehileng oa ho phekola, e leng sona feela lebaka la ho lokolloa ha formaldehyde nakong ea ho phekoloa ha li-amino resin; formaldehyde e 'ngoe ke free formaldehyde.
Ha li-amino resin li kopana ho etsa lifilimi le ho folisa, ho etsahala liketso tse ling tsa hydrolysis. Nakong ea ts'ebetso ena, lihlopha tse ling tsa alkoxymethyl li fetoloa lihlopha tsa hydroxymethyl. Hydrolysis ea li-resin tsa melamine tse nang le imino e ngata kapa hydroxymethyl e ka susumetsoa ke li-alkali, 'me e ka ba ea etsahala butle mochesong oa kamore. Sena se etsa hore li-amino resin li be kotsing ea ho itšunya-tšunya haholoanyane, e leng se lebisang keketsehong ea viscosity ea seaparo nakong ea polokelo. Ho qoba sena, li-resin tsa melamine tse nang le methyl kapa li-solvent tse loantšang alkali hydrolysis li ka sebelisoa liphahlong tse thehiloeng metsing. Li-resin tsa melamine tse nang le alkylation ka botlalo li hanela hydrolysis e entsoeng ka alkali lits'ebetsong tse thehiloeng metsing. Li-resin tsa melamine tse nang le alkylation ka botlalo le tse nang le alkylation ka karolo ha li hanele hydrolysis e entsoeng ka acid lits'ebetsong tse thehiloeng metsing; ka hona, ho lokela ho sebelisoa catalyst ea asiti e koetsoeng tsamaisong e thehiloeng metsing.
Haeba o batla ho tseba ho eketsehilengmoemeli oa khokahanolihlahisoa, ikutloe u lokolohile ho ikopanya le rona.
Nako ea poso: Tshitwe-19-2025