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Epoxy resin and coating crosslinking agent crosslinking reaction
2017-7-7 23:45:19
Epoxy resin and coating crosslinking agent crosslinking reaction
The infrared analysis of the crosslinking reaction of epoxy resin and crosslinking agent is based on m (epoxy resin E - 51) : m (homemade crosslinking agent) = 100:35 mixing uniform, the ir spectrum of the analytical system before and after crosslinking.
The characteristics of temperature Ti, Tp and Tf were respectively mapped and linear regression were performed. Article 3 curve extrapolation to beta = 0 3 point temperature as a characteristic temperature of crosslinking process, respectively defined as gel temperature Tgel (64 ℃); Tcure crosslinking temperature (77 ℃); Post-processing Ttreat temperature (115 ℃). This method has some guiding effect on the optimal crosslinking process of the system.
Cross - linking system at room temperature at normal temperature crosslinking degree. Tgel from process parameters prediction is 64 ℃, the actual meaning should be in the process of crosslinking reaction temperature, when the temperature > 64 ℃ crosslinking reactions can occur. When the quality ratio is 100:35, the crosslinking system has reached 95.4% after the crosslinking system has been handed in at room temperature.
This is due to the system as part of the epoxy resin/modified amine system of crosslinking agent, the crosslinking reaction is exothermic reaction at room temperature, the result is heat gathered themselves together, and make the system of local temperature rise, leading to more group of reaction, release more energy to continue reaction. The quality is 100:35.
Crosslinking temperature set at 65 ℃, the longer duration of crosslinking and crosslinking degree increase slowly, when the crosslinking time of 4 h, crosslinking degree reached 96.5%; Temperature to 80 ℃, and then respectively crosslinking after 2 h and 4 h, crosslinking degree is 96.6%. Compared with the normal temperature crosslinking, the crosslinking degree only increased by 1.2%, indicating that the crosslinking agent has a high reaction activity at normal temperature and can achieve high crosslinking degree.
When the intersection is nearly complete, because the kinetic resistance of the molecular chain increases, the chain segment does the same movement for a longer time, so the increment of the crosslinking degree is small. Crosslinking degree reached 96.6%, almost completely crosslinking can be thought of, considering the economic factors, do not need to predict process parameters of 115 ℃ for post-processing.
Homemade crosslinking agent can be used in a room temperature crosslinking, if necessary can take heat crosslinking in the crosslinking reaction process, so that we can eliminate the system residual internal stress, improve the mechanical properties of crosslinked with heat resistance, thus the crosslinking process for lab room temperature / 24 h + 80 ℃ / 2 h.
Chinese name: Diethyl toluene diamine(DETDA)Diethyltoluenediamine packing： net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).
Made by the different dosage of crosslinking agent resin casting body, normal temperature / 24 h + 80 ℃ / 2 h after crosslinking, the natural cooling and test its performance.
The mechanical properties of casting body are related to the amount of crosslinking agent. With an increase in the amount of crosslinking agent, bending strength, tensile strength, compression strength decrease after rising first, this is mainly because with the increase of crosslinking agent, have enough lively epoxy group and hydrogen reaction, crosslinking reaction more fully, can form a three-dimensional structure, so as to make the mechanical performance is getting better and better.
But when the dosage of the cross-linking agent reach theory, increase its dosage, makes mechanical performance degradation, it is because the active hydrogen excess, do not have enough of epoxy group and reaction, make excessive amounts of crosslinking agent residue in the crosslinking system, system of crosslinking density is insufficient, so as to make the mechanics performance degradation, and the elongation at break, may be too much crosslinking agent have the effect of toughening in the system.
Quality than for 100: Tg was 268.4 ℃, 100:35 Tg reached up to 280.3 ℃, and 100-40 Tg 274.2 ℃ and the thermo-gravimetric curve falling all the time, show that small molecules are released, it was because of excess crosslinking agent. Therefore, the ideal quality ratio is 100:35, which is consistent with the theoretical equivalent ratio.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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