Type latent curing agent

Type latent curing agent, type latent curing agent mixed with epoxy resin, the relative long-term stability at room temperature (general requirements in more than 3 months, just have large practical value, the ideal insist on half a year or more than one year), and only when it is exposed to heat, light, moisture and other conditions, the curing reaction.

Type latent curing agent is basically closed the activity of curing agent with physical and chemical method. In curing agent for the common use of curing agent, on show in the type of curing agent, dicyandiamide, adipic acid hydrazide such varieties, insoluble in epoxy resin at room temperature, and dissolved at high temperature after curing reaction, and therefore presents a latent state.

So, in some book also put these varieties is divided into type latent curing agent. In fact could be called functional type latent curing agent. Because type latent curing agent can be mixed with epoxy resin made from a type liquid complexes, simplify the procedures of the application of epoxy resin with, its application range from single to coating packaging adhesives, impregnating varnish, potting compound, powder coating, etc. Type latent curing agent is becoming more and more attention in abroad, can be said to be the focus of the research and development project, different curing agent modified varieties and new technologies emerge in endlessly, very active.

In curing agent (hereinafter referred to as the curing agent) can be divided into the addition polymerization and catalysis. The so-called addition polymerization type or open ring of epoxy group addition polymerization, curing agent to attend to the 3 d mesh structure itself. Too little for the amount of this kind of curing agent, such as, the solidifying product connected at the end of the reaction of epoxy group.

Therefore, for this kind of curing agent, there is a suitable dosage. While type catalytic curing agent by cation, or anion way make epoxy open-loop addition polymerization, in the end, the curing agent does not attend to the mesh structure, so there is no such as the appropriate dosage of equivalent reaction; However, increasing the dosage can make the curing speed.

Addition polymerization type curing agent has multiple amine, anhydride, polyphenol, mercaptan, etc. One of the most important, is the most widely used multivariate amine and acid anhydride, multivariate amine accounted for 71% of the total curing agent, anhydride class accounted for 23%. From the perspective of application, the most diverse amine by modification, and acid anhydride is more to the original state, or two, three types of low temperature eutectic mixture.

Curing agent curing temperature and curing of heat resistance

All kinds of different curing temperature curing agent, curing of heat resistance is different also. Generally speaking, the use of high curing temperature of curing agent can get heat curing. For addition polymerization type curing agent, curing temperature and heat resistance increase in the following order:




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.


Fatty polyamine < alicyclic amine more phenolic < < more aromatic amine material anhydride

Catalytic addition polymerization type heat resistance of curing agent is generally in the fragrant polyamine levels. Type anionic polymerization (tertiary amine and imidazole antiquities), cationic polymerization (BF3 complex) heat resistance is basically the same, this is mainly from the reaction mechanism is different, but in the end all the reticular structure of ether bond.

Curing reaction belongs to the chemical reaction, is highly affected by the curing temperature and higher temperature, reaction speed, gel time shorter; The gel time of numerical straight decline roughly along with curing temperature rise. But curing temperature is exorbitant, often make the curing performance degradation, so has the upper limit of curing temperature; Must choose the curing speed and the temperature of the curing performance tradeoffs, as a suitable curing temperature.

Curing agent at the curing temperature can be divided into four categories: low temperature curing agent curing temperature under room temperature. Room temperature curing agent curing temperature to room temperature ~ 50 ℃; Medium temperature curing agent is 50 ~ 100 ℃; High temperature curing agent curing temperature above 100 ℃. Belongs to low temperature type of curing agent varieties, rarely have poly ryukyu, more isocyanate, etc. In recent years, the domestic production of T - 31 of modified amine, YH - 82 modified amine curing below 0 ℃.

Belong to many different kinds of room temperature type: aliphatic amine and alicyclic amine; Low molecular polyamide and modified aromatic amine etc. Belongs to the medium temperature type of a part of alicyclic amine and tertiary amine, narrow azole and boron trifluoride complex, etc. Belong to type of high temperature curing agent with aromatic amine and acid anhydride, JiaJie phenolic resin, amino resin, the dicyandiamide and hydrazide.

For high temperature curing system, curing temperature is generally divided into two stages, using low temperature curing, in front of the gel in gel or a bit higher than the gel state of the state, after the high temperature heating curing (post - cure), relative before the period of curing for procuring (pre - cure).

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