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Heat - type latent paint crosslinking agent
2017-8-7 23:35:37
Heat - type latent paint crosslinking agent
The heated latent paint crosslinking agent is usually solid at room temperature and is not soluble in epoxy resin. When heated to near the melting point, it begins to dissolve and react rapidly.
The agent of the heating type latent sex agent has dicyandiamide and its derivatives, organic acid hydrazine, BF3 amine complex, diamine nitrile nitrile and its derivatives, imidazolite compounds and so on.
Dicyandiamide and its modified products. Dicyandiamide were the first to use the heating type latent sexual intercourse agent, also known as cyanide diamine, dicyandiamide, white crystalline powder, melting point 209 e, is still widely used in adhesives, powder coating and glass laminate, etc. Dicyandiamide is often dispersed in epoxy resin in powder form, which can be stored for up to six months at normal temperature.
Although the stability of dicyandiamide is good, the crosslinking temperature is the biggest disadvantage (the cross-linking condition is about 170e, 20 ~ 60min cross-linking). Therefore, it is usually necessary to cooperate with various accelerators to reduce the crosslinking temperature.
The promoters of dicyandiamide are mostly alkaline compounds, such as urea derivatives, imidazole and its derivatives, tertiary amine and hydrazine. The adverse effect of using accelerant is to shorten the storage period of crosslinking agent, and the water resistance can also be affected. In order to overcome this shortcoming, the chemical modification of dicyandiamide is carried out at home and abroad, and a large number of dicyandiamide derivatives are synthesized.
This kind of modified product can be completely mutual with epoxy resin, which can be crosslinked quickly and has long storage period. The use of epoxy propane and dicyandiamide was used to produce md-02 crosslinking agent, and its melting point 154 ~ 162e, which is about 45e lower than the melting point of dicyandiamide. The formula of 100 e-44 epoxy resin, 15 md-02 and 0.5 part 2-methylimidazole was used, and the gel time of 150e was 4min.
The mixed solubility and reaction activity of phenylamine - formaldehyde modified double - cyanide were increased and the application period was longer. Modified dicyandiamide can be dissolved in the mixed solvent of alcohol and acetone, and acrylic acid under the action of passivation imidazole, 125 e can be cross-linked epoxy resin, the crosslinking material has good performance and resistance to hot and humid performance at room temperature.
Organic acid hydrazine can be prepared from fatty acid ester and hydrazine hydrazine. Directly by the organic acid ester synthesis hydrazide, although with a mixture of epoxy resin at room temperature has long storage period, but high crosslinking temperature (160 ~ 170 e), in use process middling to join crosslinking promoter to reduce crosslinking temperature, the promoter and dicyandiamide with basically the same.
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.
Takeuchi second-class, points out that light with dihydric phenol (such as the pyrocatechol, etc.) as the raw material of synthetic organic acid hydrazide has low temperature, rapid crosslinking performance, and storage stability, crosslinked transparent, with toughness, excellent water resistance.
Boron-amine complex. Lewis acid and primary amine or secondary amine to form complex is also a kind of effective latent sexual intercourse agent of epoxy resin, this kind of complex is very stable at room temperature, the heating is quick crosslinking, thus has been widely used. The BPEA - 2, BPEA - 2, is a mucous liquid at normal temperature and can be easily mixed with liquid epoxy resin. No heating is required, and no solvent is required.
Because the molecules contain longer molecular chains, the crosslinking has a certain toughening effect. The dosage of the crosslinking agent at normal temperature is low, and the dosage of the liquid bisphenol A epoxy resin (e.g. e-44, e-51) is 8% ~ 10%, the storage period of 25e is 120d, the cross-linking condition is 140e / 1h, and the shear strength (steel/steel) can reach 16.2 ~ 23.0 MPa.
BCL3 - amine complex, the product name acce-leratordy9577, the appearance of microyellow to brown solid liquid mixture, melting point 28e, H2O quality score 0.1%, relative density 1.1.
This complex can be used as a latent catalytic agent for liquid epoxy resins, or as a latent promoter of acid anhydride with epoxy resin. It has good compatibility with liquid epoxy resin and crosslinking agent. The crosslinking agent has no adverse effect on the electrical performance of the crosslinking system, which can be used for casting, encapsulating, wire winding structure, molding and electrical insulation tape.
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