News Details
Epoxy coating crosslinking agent
2017-8-17 12:20:26
Epoxy coating crosslinking agent
In water-based acrylic resin synthesis, the use of GMA monomer, thereby introducing epoxy crosslinking agent in macromolecular chain, can with carboxyl group in the molecule or carboxylic acid amine salt crosslinking, and can also be cross-linked with amino reaction. But this method may lead to the cross-linking of the emulsion particles, resulting in the production of gel-particles, and the hydrolysis of the epoxide.
The epoxy is a functional base with a CH (O) CH - structure. The epoxy - based crosslinking agent is characterized by strong reactivity. The molecular chain grows after the open-loop polymerization or the addition of other compounds. After the reaction of two or more epoxies and polyfunctional groups, the crosslinking structures have the crosslinking structure, which is the epoxy resin and its crosslinking.
As a result of the existence of high tension on three yuan, can make epoxy crosslinking agent under mild conditions with primary amine, thiol and hydroxyl nucleophilic ring opening reaction of reagent, respectively form secondary amine, sulfide or ether bond.
According to the chemical properties, the active hydrogen compounds can be divided into alkaline compounds (such as berine, secondary amine, amides) and acid compounds (e.g., carboxylic acid, phenol, alcohol, etc.). Their active hydrogen atoms and epoxy groups produce the following addition reactions.
Alkaline compounds react with epoxy based on nucleophilic mechanism, which is generally very alkaline, such as fatty amine > aromatic amine. Acidic compounds react with the electrophilic mechanism and the epoxy base, which is generally the most acidic activity, such as the carboxylic acid > phenol > alcohol.
The reaction of aliphatic amine and terminal epoxy can be performed at room temperature without promoting agent. However, a series of proton donor substances (such as alcohols, phenols, carboxylic acids, sulfonic acids, and water) contribute to this reaction.
And the proton acceptor substance (such as ester, ether, ketone and nitrile) inhibits it. The order of effect is: the acid is greater than or equal to the water > alcohol, > alcohol, >, > dioxane, > diisopropyl ether.
Aromatic amine is less reactive than adipocyte and is slow to react with epoxy. Only about 30% of the resins at room temperature responded. This is because the asymmetric electrons in the aromatic amine atom are partially dispersed by the benzene ring (the E effect of benzene nuclei), resulting in alkaline reduction, and the stereo-resistance effect of the benzene ring. However, aromatic amine and lipid ring epoxy are much faster than fatty amines.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
In water-based acrylic resin synthesis, the use of GMA monomer, thereby introducing epoxy crosslinking agent in macromolecular chain, can with carboxyl group in the molecule or carboxylic acid amine salt crosslinking, and can also be cross-linked with amino reaction. But this method may lead to the cross-linking of the emulsion particles, resulting in the production of gel-particles, and the hydrolysis of the epoxide.
The epoxy is a functional base with a CH (O) CH - structure. The epoxy - based crosslinking agent is characterized by strong reactivity. The molecular chain grows after the open-loop polymerization or the addition of other compounds. After the reaction of two or more epoxies and polyfunctional groups, the crosslinking structures have the crosslinking structure, which is the epoxy resin and its crosslinking.
As a result of the existence of high tension on three yuan, can make epoxy crosslinking agent under mild conditions with primary amine, thiol and hydroxyl nucleophilic ring opening reaction of reagent, respectively form secondary amine, sulfide or ether bond.
According to the chemical properties, the active hydrogen compounds can be divided into alkaline compounds (such as berine, secondary amine, amides) and acid compounds (e.g., carboxylic acid, phenol, alcohol, etc.). Their active hydrogen atoms and epoxy groups produce the following addition reactions.
Alkaline compounds react with epoxy based on nucleophilic mechanism, which is generally very alkaline, such as fatty amine > aromatic amine. Acidic compounds react with the electrophilic mechanism and the epoxy base, which is generally the most acidic activity, such as the carboxylic acid > phenol > alcohol.
The reaction of aliphatic amine and terminal epoxy can be performed at room temperature without promoting agent. However, a series of proton donor substances (such as alcohols, phenols, carboxylic acids, sulfonic acids, and water) contribute to this reaction.
And the proton acceptor substance (such as ester, ether, ketone and nitrile) inhibits it. The order of effect is: the acid is greater than or equal to the water > alcohol, > alcohol, >, > dioxane, > diisopropyl ether.
Aromatic amine is less reactive than adipocyte and is slow to react with epoxy. Only about 30% of the resins at room temperature responded. This is because the asymmetric electrons in the aromatic amine atom are partially dispersed by the benzene ring (the E effect of benzene nuclei), resulting in alkaline reduction, and the stereo-resistance effect of the benzene ring. However, aromatic amine and lipid ring epoxy are much faster than fatty amines.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The product is identical to Ethancure 100 and Lonza DETDA 80, DETDA is very effective polyurethane elastomer chain extender; also be used as polyurethane and epoxy resin curing agent, epoxy resin of an antioxidant, industrial oils and lubricants . In addition, also as intermediates in organic synthesis.Especially for the RIM (reaction injection molding), is important in the field of spray polyurea chain extender species. Also can be used for casting polyurethane elastomer (CPU) and a curing agent, epoxy curing agent, epoxy resin of antioxidants, lubricants and industrial oils other antioxidants.
This may be the reason why aromatic amine is relatively acidic. Aromatic amine and oxygen-based reactions can also be added by alcohols, phenolic seasons, boron trifluoride complexes and octase. The accelerated effect of xacylic acid on the crosslinking of adipocyte epoxy resin is particularly obvious.
The activity of the hydrogen on the amide group is much smaller. It's very difficult to react with an epoxide at room temperature. In the presence of strong alkaline promoters such as KOH, NaOH or benzoate; Or under the high temperature of 150 ℃ above to generate the cycloaddition. This reaction can be used for the modification of epoxy resin.
Alcohols are used as electrophilic agents and epoxy groups. But because of its weak acidity, namely, electrophilic is small, so without accelerator existence requires above 200 ℃ can response. The reactive activity sequence of alcohols and epoxies is: > and >. Tertiary amine such as alkaline compounds can promote the epoxy groups and hydroxyl in the quick reaction under low temperature (100 ℃).
Phenol is more acidic than alcohol. So the phenol hydroxyl group reacted faster than the hydroxyl group. To start at 200 ℃. In KOH alkali promoter, such as the reaction can at 100 ℃.
The carboxyl group reacts with the epoxy base to be slower than the amine. The high crosslinking structure can not be generated at room temperature. In 100 ℃ or more long time heating to crosslinking. The basic compounds such as tertiary amines and thylamine can promote this reaction. Toughening and crosslinking of epoxy resin and synthesis of vinyl ester resin.
Alcohol, phenol and carboxylic acid and other hydroxyl compounds and glycidyl ether reacted in the order of alkaline promoters in the order of > phenol > carboxylic acid. This is in line with the basic order of their anions.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
This may be the reason why aromatic amine is relatively acidic. Aromatic amine and oxygen-based reactions can also be added by alcohols, phenolic seasons, boron trifluoride complexes and octase. The accelerated effect of xacylic acid on the crosslinking of adipocyte epoxy resin is particularly obvious.
The activity of the hydrogen on the amide group is much smaller. It's very difficult to react with an epoxide at room temperature. In the presence of strong alkaline promoters such as KOH, NaOH or benzoate; Or under the high temperature of 150 ℃ above to generate the cycloaddition. This reaction can be used for the modification of epoxy resin.
Alcohols are used as electrophilic agents and epoxy groups. But because of its weak acidity, namely, electrophilic is small, so without accelerator existence requires above 200 ℃ can response. The reactive activity sequence of alcohols and epoxies is: > and >. Tertiary amine such as alkaline compounds can promote the epoxy groups and hydroxyl in the quick reaction under low temperature (100 ℃).
Phenol is more acidic than alcohol. So the phenol hydroxyl group reacted faster than the hydroxyl group. To start at 200 ℃. In KOH alkali promoter, such as the reaction can at 100 ℃.
The carboxyl group reacts with the epoxy base to be slower than the amine. The high crosslinking structure can not be generated at room temperature. In 100 ℃ or more long time heating to crosslinking. The basic compounds such as tertiary amines and thylamine can promote this reaction. Toughening and crosslinking of epoxy resin and synthesis of vinyl ester resin.
Alcohol, phenol and carboxylic acid and other hydroxyl compounds and glycidyl ether reacted in the order of alkaline promoters in the order of > phenol > carboxylic acid. This is in line with the basic order of their anions.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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