How much do you know about epoxy curing agents?

Epoxy curing agent is a chemical reaction with epoxy resin, forming a mesh three-dimensional polymer, the composite bone envelope in the mesh. Additives that turn line resins into tough solids.
1, curing agent classification
curing agent by use can be divided into a room temperature curing agent and heating curing agent

. Epoxy resins generally perform well when cured at high temperatures, but coatings and adhesives used in civil buildings require temperature curing due to heating difficulties, so most use fatty amines, lipid rings and polyamides, especially in winter, coatings and adhesives have to be used in the same with polycyanate, or use polylyools with a foul odor.
varieties of curing agents have a great influence on the chemical properties, heat resistance, water resistance, corrosion resistance, etc. of curing agents such as aromatic polyamines, mides, acids and so on, the heat resistance of curing epoxy resins is higher than that of fat groups. Polyamine, low molecular polyamide curing agent, aromatic acid anhydride curing epoxy resin water resistance is better than aromatic diamine and adipose polyamine curing agent, acidic curing agent curing epoxy resin resistance is better than acid resistance. Appropriate curing agents should be selected according to different uses and performance requirements.
the curing temperature of various curing agents varies widely, and the heat resistance of curing materials varies greatly. Generally speaking, the use of curing agent with high curing temperature can obtain excellent curing resistance. For added polymeric curing agents, curing temperature and heat resistance are increased in the following order:
adipose polyamines< lipopycycline polyamines < Aromatic polyamines≈phenol aldehydes 2, curing agent selection points
Curing agent selection: curing agent to epoxy resin The performance impact is greater, generally according to the following points of choice:
(1), from the performance requirements of the choice: some requirements of high temperature resistance, some requirements of good flexibility, some requirements of good corrosion resistance, according to different requirements to choose the appropriate curing agent
;
(3), from the application period to choose: the so-called applicable period, that is, the epoxy resin added to the curing agent from the time to the time when it cannot be used. To be applicable for a long period of time, the general choice of acid anhydride or latent curing agent;
(4), from the safety of the choice: generally requires less toxicity for good, easy to safe production,
(5), from the cost of choice.
3, curing agent in epoxy floor paint use
due to epoxy paint "curing agent" literally understood to be biased, many people will understand the curing agent as a help to cure epoxy resin additives, as long as the addition of curing agents, epoxy resin will cure into the floor, as long as the addition of enough curing agents, curing speed will be faster.
This concept led many users to buy epoxy floor paint, will ask merchants to distribute more curing agents, because they feel that as long as the curing agent more points, you can accelerate the curing speed of epoxy flooring, thereby reducing the construction time to a shorter. In fact, this is an unrealistic approach, on the contrary, curing agents have been added, in fact, the curing speed is slower, and there may even be non-curing situations.
The reaction process between the epoxy resin and the curing agent is a chemical reaction process in which the oxycodone in the resin is opened by a closed state and then recombined with the hydrogen-oxygen bond in the curing agent to form a new closed ring. This new closed-loop cross-interconnect, forming a solid three-dimensional structure, the new structure is in a very stable state, this state gives the epoxy floor paint strong mechanical properties and chemical resistance, for daily wear or chemical resistance or chemical agents have good resistance.
Since the curing process is a chemical reaction process, there must be a problem of ratio of the quality of the reaction components, only when the epoxy resin and curing agent reach a balanced state, the curing reaction can be both adequate and appropriate. When there are too many curing agents, open ring epoxy resin has been linked with enough curing ingredients, more curing agent can not find more open ring resin, so it can only free in the original state in the epoxy paint film; This is usually seen can not cure the situation, too much or too little curing agent, will affect the quality of film.
addition, uneven mixing is also a serious problem affecting the curing reaction. Many users in accordance with the factory ratio of materials after the construction still appear uncoverable situation, this is a typical case of uneven mixing. Resin and curing agent good reaction requires two materials to mix correctly together, stirring is not equal, the two lacquer liquid can not be good fusion, no contact with the material will not react, so can only maintain their original liquid state, the performance of the paint liquid can not dry, or long-term treatment of the sticky state of the situation.
4, curing agent in powder coating application
does not need curing agent in thermoplastic powder coating, but in thermostate powder coating, curing agent is an essential component in the composition of powder coating, if there is no curing agent, thermoclytic powder coating can not cross-curing into a film with a certain physical force and chemical resistance properties of the coating. The properties of curing agents are the main factors that determine the performance of powder coatings and coatings.
curing agent should have good chemical reaction activity with resin, in normal mild melt extrusion mixing temperature conditions do not have a chemical reaction with resin, and under baking curing conditions, with the resin quickly cross-linked curing reaction, to obtain good appearance leveling, physical and aesthetic properties and chemical resistance performance of good coating film.
considering the manufacturing process and storage stability of powder coatings, curing agents are solids, not liquids, under normal or room temperature conditions, preferably solid powdered or easily crushed solid grains or flakes.
from the consideration of energy conservation, the curing agent and resin cross-curing reaction temperature is low, the reaction time is short, which is conducive to low temperature short-term curing into a film, can save energy and improve production efficiency.