Add molding coating cross-linking agent

Add molding coating cross-linking agent: this kind of crosslinking agent addition reaction with epoxy group forming of the crosslinked product chain segment, and step by step through polymerization reaction molecules form the couplet body structure, this kind of crosslinking agent is also called the melon type of cross-linking agent.

Yellowing of hydroxyl alkyl amide since it is generated by bare nitrogen atoms in the molecule, obviously change the state of the bare nitrogen atoms become solve the problem of yellowing junction is located. Closed or shielding the nitrogen atom in the molecule to prevent its oxidation is, of course, have a certain effect of solution (such as add some antioxidant), to reduce the amount of nitrogen atom exposed also can yet be regarded as a good solution.

To reduce the amount of nitrogen atom exposed to so-called is actually reducing the proportion of hydroxyl alkyl amide in the system. This would require the production enterprises with low acid value resin (25 kohmg/g) or less carboxyl polyester, the proportion of both by the past 95:5 reduced to 96.5:3.5.

It should be pointed out that reducing the amount of hydroxyl alkyl amide, not only can improve the coating yellow degeneration, but also because of the lower formation water and reduced the incidence of pinhole, improve the surface of the coating at the same time, should be a good measure of kill two birds with one stone. The problem is that reduce the acid number of polyester, practical to a certain extent, reduced the crosslinking density of the coating, may affect the physical and chemical properties of the coating.

So for hydroxyl alkyl amide in terms of low acid value of carboxyl polyester, yellow degeneration and physical and chemical properties of balance measure its quality should be qualified. If can keep yellow degeneration and the balance of physical and chemical properties, are based on the differences of yellow degeneration can determine the quality level.

All samples were basically can achieve the balance of yellow degeneration and physical and chemical properties. The resin A especially yellowing resistance; Resin B impact resistance performance is unqualified, the main cause is a decline in the film crosslinking density, the acid value of resin and Tg analysis, the reason may come from the resin itself functions of low and high molecular weight; Resin F yellowing resistance is poorer, not suitable for the application of light color powder coating.




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.


The influence of polyester resin on the processing performance. HAA, in the process of powder coating processing general extruder set temperature is higher than resin softening point 10 to 20 degrees.

Under the same extruder set temperature, high softening point polyester, in the process of machining, is advantageous to the depolymerization dispersion of fillers, but due to wetting effect is not obvious, resin is not fully covering other materials, which can lead to coating on the surface of the fog, the phenomenon such as loss of light; Low softening point of polyester, processing performance is outstanding, effect is good, suitable for surface flow leveling performance outstanding powder, such as the resin in table a G can get very good flow flat.

Due to the difference in the softening point of each manufacturer resin, so in the actual production process, should according to their own conditions to choose different polyester.

Polyester resin on the properties of storage stability. General powder coating glass transition temperature (Tg) determine the storage stability of powder coatings, and powder coating T * * generally by the Tg of the resin and the dosage of low molecular organic compounds. For different storage conditions, different climate condition, should choose to T * * of the resin.

HAA system powder Tg generally lower Tg of about 8 degrees than polyester resin, powder coating Tg 54 degrees or more, has good storage stability; For TGIC system also made relevant test, the average drop around 15 ℃. In general, the decline of HAA system smaller than TGIC system declines, therefore when choosing HAA system resin, except for some special high temperature storage, generally can choose low Tg of resin, which can achieve ideal surface effect, at the same time also can guarantee the storage stability of powder coatings.

Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd 

Diethyl toluene diamine(DETDA)  http://www.yaruichem.com