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    Home > Coatings News > Paints and Coatings Market > Types and properties of epoxy curing agents

    Types and properties of epoxy curing agents

    • Last Update: 2020-02-21
    • Source: Internet
    • Author: User
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    according to thethe epoxy resin curing agent can be divided into: dominant curing agent, latent curing agentthe solidified agent is a curing agent for common use, and can be divided into additive polymerization and catalytic typeThe so-called additive polymerization type is to open the epoxy-based epoxy-based epsitation polymerization reaction, curing agent itself to participate in the three-dimensional mesh structureSuch curing agents, if added too little, the curing product is connected to the epoxy of the last reactionTherefore, for this type of curing agent, there is a suitable dosageThe catalytic curing agent is in the form of cation, or anion way to make the epoxy-based open-loop aggregation, and finally, curing agent does not participate in the mesh structure, so there is no equivalent reaction of the appropriate dosage;additive polymeric curing agents are polyamine, anhydride, polyphenols, polythools and so onAmong them, the most important and widely used are polyamines and anhydride, which accountforforforforforforth 71% of all curing agents and acidanes account for 23%From the application point of view, most of the polyamines have been modified, while the anhydride is mostly in the original state, or two or three kinds of low-temperature cocolation mixed useand latent curing agent refers to: this type of curing agent and epoxy resin mixed, in room temperature conditions relatively stable and stable (generally requires more than 3 months, only have a greater practical value, the ideal is required for six months or more), and only need to be exposed to heat, light, moisture and other conditions, that is, the beginning of curing reactionThis type of curing agent is basically closed by physical and chemical methods of curing agent activityIn the dominant curing agent, the varieties of dicylamine, dilyceride diacetoacid, which are insoluble in epoxy resin at room temperature, and begin to cure after dissolving at high temperatures, thus showing a latent stateTherefore, some books also have these varieties classified as latent curing agent, in fact, can be called functional latent curing agentBecause the latent curing agent can be mixed with epoxy resin to make a liquid-type fit, simplify the co-operation procedures of epoxy resin application, the application range from single-pack adhesive to coating, impregnated paint, potting material, powder coating and other aspects of developmentLatent curing agent in foreign countries increasingly attracted attention, can be said to be the focus of research and development, a variety of curing agent modification of new varieties and new technologies emerge endlessly, very activethe curing temperature of various curing agents varies, and the heat resistance of curing agents is very differentGenerally speaking, the use of curing agents with high curing temperature can obtain excellent heat resistance curing materialFor the addition of polymeric curing agents, the curing temperature and heat resistance are increased in the following order: fatty polyamine phonic sylphystol soforecatalytic polysacchacurer heat resistance is generally at the aromatic polyamine levelThe heat resistance of anion polymeric type (shuamine and miamine- and miamine-based antiquities) and cation-ion polymerization (BF3 complex) is basically the same, which is mainly due to the different reaction mechanism sylfied at the beginning, but ultimately forms a mesh structure bound by ether bondscuring reaction is a chemical reaction, greatly affected by curing temperature, temperature increases, reaction speed is accelerated, gel time is shorter; However, the curing temperature is too high, often make the curing material performance is reduced, so there is an upper limit of curing temperature; According to the curing temperature can be divided into four types: low temperature curing agent curing temperature below room temperature, room temperature curing agent curing temperature is room temperature to 50 degrees C, medium temperature curing agent is 50 to 100 degrees C, high temperature curing agent curing temperature is above 100 degrees CThere are very few curing agents belonging to the low temperature curing type, such as polylucol type, polyhesocyanate type, etc, in recent years, the domestic development and production of T-31 modified amines, YH-82 modified amines can be cured below 0 degrees CThere are many types of room temperature curing type: fatty polyamine, lipoly polyamine, low-molecular polyamide and modified aramidBelongs to the medium temperature curing type is a part of the lipocyclic polyamine, shuamine, tantamines and boron trifluoride, etcAmong the high temperature curing agents are aromatic polyamine, acid anhydride, formphenolic resin, amino resin, dicylamine and acetatefor high temperature curing systems, the curing temperature is generally divided into two stages, in front of the gel using low temperature curing, after reaching the gel state or slightly higher than the gel state, reheating after the curing (post-cure), relative to the previous period curing pre-curing (pre-cure)
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