Epoxy resin is an amorphous viscous liquid that is plastic when heated and has no obvious melting point. It becomes soft when heated and gradually melts, but becomes sticky and insoluble in water.After the curing agent was added into gradually solidified form of chemicals with various properties, therefore, must add hardener, the formula of resin, and under certain conditions for curing reaction, generate the product of the three-dimensional network structure, will appear a variety of excellent performance, an epoxy material has actually use value.Common amine curing agent in engineering: ethylenediamine, ethylene polyamine, polyethylene polyamine, etc.
Curing agent is an indispensable additive, which is needed for adhesives, coatings and castables, otherwise epoxy resin cannot be cured.
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Increase toughness and impact resistanc
|Quartz powder, porcelain powder, iron powder, cement, emery||Improve the hardness|
|Alumina, porcelain powder||Increase adhesion, increase mechanical strength|
Asbestos powder, silica gel powder, high temperature cemen
|Improve heat resistance|
|Asbestos powder, quartz powder, stone powder||Reduce shrinkage|
Aluminum powder, copper powder, iron powder and other metal powde
|Increase thermal and electrical conductivity|
Graphite powder, talc powder, quartz powde
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Emery and other abrasives
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Mica powder, porcelain powder, quartz powder
Various pigments and graphite
Definition of curing agent for epoxy resin
React with epoxy resin to form reticular solid polymer and encase composite material in the reticular body.
Classification of curing agents for epoxy resins
(1) Alkaline and acidic curing agents:
Basic curing agents include aliphatic diamines and polyamines, aromatic polyamines, other nitrogenous compounds and modified aliphatic amines.
Acidic hardeners include organic acids, anhydrides, and boron trifluoride and their complexes.
(2) Add molding and catalytic curing agents:
Curing agents, also known as melon curing agents, are added to the epoxy group to form part of the chain segment of curing products, and the linear molecules are cross-linked to form structural molecules through gradual polymerization.This kind of curing agent can only initiate the action on the epoxy resin. After the epoxy group is opened, it can catalyze the epoxy resin itself to polymerize into the network structure and generate the homopolymer with ether bond as the main structure.
(3) Apparent hardener and latent hardener.
Apparent curing agent is a common curing agent which can be divided into addition polymerization type and catalytic type.The so-called addition polymerization is to open the epoxy ring for addition polymerization reaction, the curing agent itself to participate in the three-dimensional network structure.If too little is added, the curing product is linked to the final reactive epoxy group.Therefore, there is an appropriate dosage for this type of curing agent.However, the catalytic curing agent can make the epoxy group open ring addition polymerization in the way of cation or anion. In the end, the curing agent does not participate in the network structure, so there is no appropriate amount of equivalent reaction.However, increasing the dosage will speed up the curing process.
Latent curing agent is a kind of curing agent that is mixed with epoxy resin and relatively stable for a long time at room temperature. Generally, epoxy resin needs more than 3 months to be of great practical value. Ideally, it needs more than 6 months or 1 year.These hardeners essentially block hardener activity by physical and chemical means.In the apparent curing agent, the varieties of dicyandiamide and dihydrazide adipate are insoluble in epoxy resin at room temperature, but begin to cure after dissolution at high temperature, and thus present a latent state.So, also divide these breed in some books for latent hardener, can call function actually latent hardener.Because the latent curing agent can be mixed with epoxy resin to make a liquid compound, the application of epoxy resin can be simplified. Its application range has developed from single-package adhesive to coating, impregnating paint, filling and sealing material, powder coating and other aspects.Latent curing agent has been paid more and more attention in foreign countries. It can be said that it is a key subject of research and development
QuanZhou Neweco High Polymer Material Co.,Ltd.
Neweco is one of the leading unsaturated polyester resin manufacturers and suppliers,widely used in automobiles, ships, rail transit, wind power generation, pipe cans, heat and corrosion protection, building materials, stone repair, sanitary ware, artificial stone and other industries. Suitable for hand lay-up, spray, pultrusion, winding, molding, vacuum introduction / RTM, casting and other molding processes. Neweco Resin is committed to excellence and focuses on the application of composite materials to provide customers with comprehensive solutions.