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An acid anhydride cross-linking agent for epoxy coatings
2017-9-2 17:15:38
An acid anhydride cross-linking agent for epoxy coatings
The characteristics of epoxy resin coatings used in epoxy resin are: the crosslinking reaction is slow and the heat is gentle, the cross-linking film shrinkage is small; The heat deformation temperature of the crosslinking object is high, and the film is resistant to chemical properties, uv and heat resistance. Film - coated mechanics and excellent electrical performance. As a result, it is mainly used as electrical insulation.
On the other hand, the acid anhydride cross-linking agent has the following disadvantages as epoxy crosslinking agent. When crosslinking reaction, the CO2 is out, easy to make the inside of the film forming pinhole; Most solid acid anhydride is easy to sublimate, the construction has strong pungent smell. Due to the poor performance of the cross-linking coating, it is less used in decorative powder coatings.
Because anhydride crosslinking agent itself does not contain active hydrogen, cannot be directly react with epoxy group, must add crosslinking accelerator open the anhydride ring first, commonly used promoters have mentioned imidazole and its derivatives as well as on the quaternary ammonium salt, quaternary phosphonium salt Weng salts, etc.
In principle, all low molecular weight anhydride, such as phthalic anhydride, maleic anhydride and phthalic anhydride can be used as epoxy resin crosslinking agent. Some varieties, such as trimellitic anhydride (TMA), and all four benzene acid dianhydride, although for can obtain better performance of coating has been widely used, but because of its toxicity and has certain strong excitant and easy sublimation release, therefore has gradually been banned.
Other commonly used there are four hydrogen of benzene anhydride type epoxy crosslinking agent (THPA) dimethyl anhydride, methyl hydrogen dimethyl benzene anhydride (MTHPA), 3, 3 ', 4, 4 '- phenyl ketone four acid dianhydride (BTDA), poly (azelaic acid anhydride and kwai anhydride, etc.
Acid anhydride is an oxygen-containing acid that removes a molecule of water or a few molecules of water, the rest of it. The common inorganic acid is the acid of a molecule, which directly loses the water of a molecule to form the acid anhydride of the acid, and its acid anhydride determines the valence of the acidic element. The organic acids are the two molecules of the acid or polymolecule that are formed by the reaction of the molecules. Only oxygenated acid is the only acid anhydride. Anaerobic acid is not anhydride.
Acid anhydride is generally considered to be an oxide of acid dehydration. Many can rehydrate with water to become the original acid.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The characteristics of epoxy resin coatings used in epoxy resin are: the crosslinking reaction is slow and the heat is gentle, the cross-linking film shrinkage is small; The heat deformation temperature of the crosslinking object is high, and the film is resistant to chemical properties, uv and heat resistance. Film - coated mechanics and excellent electrical performance. As a result, it is mainly used as electrical insulation.
On the other hand, the acid anhydride cross-linking agent has the following disadvantages as epoxy crosslinking agent. When crosslinking reaction, the CO2 is out, easy to make the inside of the film forming pinhole; Most solid acid anhydride is easy to sublimate, the construction has strong pungent smell. Due to the poor performance of the cross-linking coating, it is less used in decorative powder coatings.
Because anhydride crosslinking agent itself does not contain active hydrogen, cannot be directly react with epoxy group, must add crosslinking accelerator open the anhydride ring first, commonly used promoters have mentioned imidazole and its derivatives as well as on the quaternary ammonium salt, quaternary phosphonium salt Weng salts, etc.
In principle, all low molecular weight anhydride, such as phthalic anhydride, maleic anhydride and phthalic anhydride can be used as epoxy resin crosslinking agent. Some varieties, such as trimellitic anhydride (TMA), and all four benzene acid dianhydride, although for can obtain better performance of coating has been widely used, but because of its toxicity and has certain strong excitant and easy sublimation release, therefore has gradually been banned.
Other commonly used there are four hydrogen of benzene anhydride type epoxy crosslinking agent (THPA) dimethyl anhydride, methyl hydrogen dimethyl benzene anhydride (MTHPA), 3, 3 ', 4, 4 '- phenyl ketone four acid dianhydride (BTDA), poly (azelaic acid anhydride and kwai anhydride, etc.
Acid anhydride is an oxygen-containing acid that removes a molecule of water or a few molecules of water, the rest of it. The common inorganic acid is the acid of a molecule, which directly loses the water of a molecule to form the acid anhydride of the acid, and its acid anhydride determines the valence of the acidic element. The organic acids are the two molecules of the acid or polymolecule that are formed by the reaction of the molecules. Only oxygenated acid is the only acid anhydride. Anaerobic acid is not anhydride.
Acid anhydride is generally considered to be an oxide of acid dehydration. Many can rehydrate with water to become the original acid.
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.
According to the properties of acids can be divided into:
(1) the acid anhydride of inorganic acid is reduced by one or two acids. For example, carbon (acid) anhydride (acid) is carbon dioxide (CO2), nitric acid (acid) anhydride (acid) and nitric oxide (N2O5).
(2) acid anhydride of organic acids, compounds that are reduced by two mono-acid molecules or a divalent molecule, though not oxides, also known as anhydride. For example, b (acid) anhydride (CH3CO) 2O, phthalic anhydride C8H4O3, etc.
"Acid anhydride is acid oxide" is true in a certain range. Acid anhydride is formed by acid dehydration, while acid oxide reacts with alkali to form the salt and water oxides. Conceptually, they are not equivalent. Anhydride in inorganic chemistry is the formation of acid dehydration, and the vast majority of oxide, so they can be equal, but in organic chemistry, many organic acids are not oxide after dehydration, such as acetic acid (CH3COOH), dehydrated to form acetic anhydride ((C4H6O3, (CH3CO) 2 o), so it can't be acidic oxides.
A chemical compound, such as a carbonic acid molecule (H2CO3) that shrinks to a molecule of water (H2O), is a carbonic anhydride. The two vinegar molecules (CH3COOH) are reduced to a molecule of water (H2O) and the rest of the (CH3CO) 2O is the acetic anhydride.
Varieties of crosslinking agent on the crosslinking content on the mechanical properties, heat resistance, water resistance, corrosion resistance and so on have very big effect, such as the heavy aromatic amine, imidazole, acid anhydride and crosslinker crosslinked heat resistance of the epoxy resin is higher than aliphatic amine, low molecular polyamide crosslinking agent; The water resistance of aromatic acid anhydride with epoxy resin is better than that of aromatic diamine and fatty polyamide crosslinking agent. The triethylamine cross-linking agent of sanya is good for alkali resistance, but it has poor acidity and formaldehyde solution. The drug resistance of polyamine (e.g., isovolidone diamide) is excellent. Acid anhydride crosslinking agent crosslinked epoxy resin is better than acid resistance. Appropriate crosslinking agents should be selected according to different USES and performance requirements.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
According to the properties of acids can be divided into:
(1) the acid anhydride of inorganic acid is reduced by one or two acids. For example, carbon (acid) anhydride (acid) is carbon dioxide (CO2), nitric acid (acid) anhydride (acid) and nitric oxide (N2O5).
(2) acid anhydride of organic acids, compounds that are reduced by two mono-acid molecules or a divalent molecule, though not oxides, also known as anhydride. For example, b (acid) anhydride (CH3CO) 2O, phthalic anhydride C8H4O3, etc.
"Acid anhydride is acid oxide" is true in a certain range. Acid anhydride is formed by acid dehydration, while acid oxide reacts with alkali to form the salt and water oxides. Conceptually, they are not equivalent. Anhydride in inorganic chemistry is the formation of acid dehydration, and the vast majority of oxide, so they can be equal, but in organic chemistry, many organic acids are not oxide after dehydration, such as acetic acid (CH3COOH), dehydrated to form acetic anhydride ((C4H6O3, (CH3CO) 2 o), so it can't be acidic oxides.
A chemical compound, such as a carbonic acid molecule (H2CO3) that shrinks to a molecule of water (H2O), is a carbonic anhydride. The two vinegar molecules (CH3COOH) are reduced to a molecule of water (H2O) and the rest of the (CH3CO) 2O is the acetic anhydride.
Varieties of crosslinking agent on the crosslinking content on the mechanical properties, heat resistance, water resistance, corrosion resistance and so on have very big effect, such as the heavy aromatic amine, imidazole, acid anhydride and crosslinker crosslinked heat resistance of the epoxy resin is higher than aliphatic amine, low molecular polyamide crosslinking agent; The water resistance of aromatic acid anhydride with epoxy resin is better than that of aromatic diamine and fatty polyamide crosslinking agent. The triethylamine cross-linking agent of sanya is good for alkali resistance, but it has poor acidity and formaldehyde solution. The drug resistance of polyamine (e.g., isovolidone diamide) is excellent. Acid anhydride crosslinking agent crosslinked epoxy resin is better than acid resistance. Appropriate crosslinking agents should be selected according to different USES and performance requirements.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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