News Details
Epoxy Floor Coating Crosslinking Agent
2017-7-11 19:48:48
Epoxy Floor coating crosslinking agent commonly used is diaminodiphenyl sulfone (DDS), epoxy / DDS system heat resistance (Tg) is high, but the moisture absorption, poor heat resistance, and high density, resulting in the system Brittle.
In order to improve the wet heat performance and toughness of the epoxy resin matrix, the following various epoxy floor paint cross-linking agents have been developed: Polyether diamine type crosslinking agents include diaminodiphenyl ether diphenyl sulfone (BDAS), diamino Diphenyl ether diphenyl ether (BDAO), diaminodiphenyl ether bisphenol A (BDAP), diaminodiphenyl-6F-bisphenol A.
Compared with DDS other diamine epoxy floor paint cross-linking agent due to the distance between the two ends of the amine longer, resulting in the reduction of amino point of water absorption, and thus water absorption decreased, and has excellent impact resistance. Although the cross-linking agent on the flexible ether bond more, leaving the heat resistance after drying has declined. But because of the aromatic ring and more heat resistance decreased much. In addition, due to small water absorption, due to water heat caused by the decline in heat is also small.
The cross-linking agent, EponHPT1061 and 1062, which are free of ether bonds, are crosslinked (basic), and the moisture absorption rate is also significantly lower than that of DDS due to the large amount of hydrogen bonds.
In the EponHPT107l and l072 resin with l061 and 1062 cross-linking agent, the dry heat resistance (Tg) is lower than the DDS of about 10 ℃, 250 ~ 241 ℃, but the water absorption decreased further, 1.6% to 1.4% The Not only to maintain the elastic modulus of water absorption, the other physical properties are further improved.
Various diamine compounds with fluorene as the skeleton are used as heat-resistant and moisture-resistant crosslinking agents for epoxy resins. At the same time, excellent water absorption is obtained.
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.
(DGEBA) and fluorene epoxy (DGEBF) crosslinked by the above-mentioned crosslinking agent had a water absorption of only 1.4% to 2.2% under the conditions of relative humidity of 100% and temperature of 95 ℃. This shows that fluorenyl is a very hydrophobic structure. With the molecular chain extended, water absorption decreased significantly.
When the crosslinking temperature of the system is 100 ℃, the value of Α is increased significantly, which indicates that the increase of energy (temperature) is the main factor affecting α. The temperature rose to 120 ° C, A was 3.6% higher than 100 ° C, then increased to 130 ° C, and an increase of 0.7% over 120 ° C. When the temperature is higher than 100 ℃, the effect of increasing the crosslinking temperature on the conversion rate is weakened.
This is because when the degree of cross-linking is large, the increase in the cross-linking degree is reduced due to the increased movement of the molecular chain and the longer the time required for the segment to do the same movement. 130 ° C crosslinked for 2 h, 87.3% for crosslinking, and 95.0% for crosslinking for 4 h, which can be considered to be completely cross-linked. It shows that prolonging the crosslinking time is more effective when the crosslinking degree is higher.
Although the process parameters are predicted in the post-treatment temperature of 197 ℃, but considering this high temperature, the formation of cross-linked equipment and auxiliary materials have a higher demand, will increase the cost, and may increase the product stress. Therefore, post-crosslinking is not recommended when the cross-linking process is determined, but complete crosslinking is achieved by prolonging the holding time at 130 ° C.
The 3221 resin system can be completely cross-linked at 130 ℃, and the crosslinking time is 4h. The crosslinking process is reasonable by DSC method.
The crosslinking temperature of the 3221 epoxy crosslinking system can be reduced by about 50 ℃ with the addition of urea as the crosslinking accelerator of dicyandiamide, and the crosslinking reaction can be alleviated at 130 ℃. The activation energy Ea of the dicyandiamide crosslinked 3221 system calculated by Kissinger equation is 142kJmol, the activation energy Ea of the dicyandiamide and substituted urea combined with 3221 system is 84.2kJmol, which further shows that the substituted urea is the effective promotion of dicyandiamide Agent.
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