The epoxy resin curing agent is usually used when decorating the house, and the price varies, and there are many types of epoxy resin curing agents. So what are the types of epoxy resin curing agents, and the epoxy resin curing temperature is How much, let the epoxy resin manufacturer introduce it to you in detail below!
Epoxy resin manufacturers
First, what kind of epoxy resin curing agent
1. Aliphatic amines: The main varieties are ethylene diamine, diethylene (poly) triamine, polyethylene (poly) polyamine, etc. It is characterized by curing at room temperature, fast curing speed, low viscosity high temperature resistant paint, easy to mix with other resins, and easy to operate. The coating film has high solvent resistance. However, the toxicity is large, the heat release during curing is large, the service life is short, the curing is limited by the temperature and humidity conditions, and the paint film is whitened under the conditions of high humidity. It has the disadvantages of orange peel and shrinkage, and the heat resistance and mechanical strength of the paint film after curing are poor.
2. Aromatic amines: mainly m-phenylenediamine, m-xylylenediamine, etc. Its characteristic is that it needs to be cured under heating conditions, it is inconvenient to mix with resin, and the heat resistance and corrosion resistance of the cured product are more prominent. It is mainly used for heating and curing process, and can also be used as raw material for modified amine curing agent.
3. Amine modified curing agent: mainly include amine addition curing agent (such as 590, 593 curing agent), T31 curing agent, phenol amino alcohol curing agent. This is mainly aimed at the toxicity of aliphatic amines and aromatic amines.The original amine curing agent is improved through addition reaction or condensation reaction.It is characterized by greatly reduced volatility, and is called low-toxic or non-toxic curing agent. The customer service takes care of the shortcomings of blushing and no induction period is required. However, the amount of curing agent increases, the amount can be changed within the range of Jiaotong University, and a better range of dosage is determined through experiments. Due to the introduction of a new molecular structure into the amine-modified curing agent molecule, the performance of the coating process and the properties of the cured coating have been changed to varying degrees, such as the low temperature and humidity curing, the corrosion resistance and temperature resistance of the coating film. Both can be improved.
Second, epoxy resin curing agent temperature
The curing temperature of each curing agent is different, and the heat resistance of the cured product is also very different. Generally speaking, using a curing agent with a high curing temperature can obtain a cured product with excellent heat resistance. For the addition polymerization type curing agent, the curing temperature and heat resistance are improved in the following order: aliphatic polyamine <alicyclic polyamine <aromatic polyamine ≈phenolic <anhydride.
The heat resistance of the catalytic addition polymerization type curing agent is generally at the level of aromatic polyamines. The heat resistance of anionic polymerized (tertiary amine and imidazole compounds) and cationic polymerized (BF3 complex) is basically the same. This is mainly because although the initial reaction mechanism is different, they eventually form a network structure of ether bonds. .
The curing reaction is a chemical reaction, which is greatly affected by the curing temperature.The temperature increases, the reaction speed is accelerated, and the gel time becomes shorter; the logarithm of the gel time generally decreases linearly with the increase of the curing temperature, but the curing temperature is too high, which often causes The performance of the cured product is reduced, so there is an upper limit of the curing temperature; a temperature that compromises the curing speed and the performance of the cured product must be selected as the appropriate curing temperature.
According to the curing temperature, the curing agent can be divided into four categories: the curing temperature of the low temperature curing agent is below room temperature; the curing temperature of the room temperature curing agent is room temperature ~ 50 ℃; the curing temperature of the intermediate temperature curing agent is 50 ~ 100 ℃; the curing temperature of the high temperature curing agent is above 100 ℃ . There are few types of curing agents that belong to low-temperature curing types, such as poly-alcohol type and polyisocyanate type. T-31 modified amine and YH-82 modified amine developed and put into production in China can be cured below 0℃. There are many types of room temperature curing type: aliphatic polyamines, alicyclic polyamines; low molecular weight polyamides and modified aromatic amines. Some of the middle-temperature curing types include cycloaliphatic polyamines, tertiary amines, azoles, and boron trifluoride complexes. High-temperature curing agents include aromatic polyamines, acid anhydrides, resol resins, amino resins, dicyandiamide, and hydrazides.