In order to improve the degree of construction of the resin products and the function of the subsequent products without changing the gender, manufacturers always hope that the resin can be cured as quickly as possible. For a certain reactive unsaturated resin, the amount of curing agent and accelerator added has a great influence on the curing speed of the resin and the subsequent curing level.
Through theory and practice, we have summarized the following curing laws of unsaturated polyester resins:
1. When using unsaturated resins, a sufficient amount of curing agent should be added to ensure sufficient exothermic peak temperature to achieve a higher curing level. (Too little curing agent may cause permanent undercuring of resin crafts)
2. When using unsaturated polyester resin. Under the condition of high ambient temperature, the amount of accelerator can be appropriately reduced to obtain a sufficiently long gel time and a more complete curing effect.
3. In the manufacture of unsaturated resin products, the general molar ratio of accelerator to curing agent (peroxide) must be less than 1, (this case can only be calculated if cobalt salt is selected as the promoter), otherwise the accelerator and The reverse speed of the primary radical will be greater than the speed of the primary radical-initiating monomer, which results in a reduction in conversion rate. Therefore, the excessive application of accelerators can not achieve the effect of accelerating curing, but will reduce the function of unsaturated resin.
4. For the curing of polyester resin with low reactivity that does not reach the maximum limit, a low-activity curing system should be used.
5. Under the unfavorable curing conditions of low temperature or high humidity, Kebao chemical manufacturers believe that the composite curing system can be accepted: normal temperature 25 degrees
Methyl ethyl ketone peroxide 1%
Benzoyl peroxide 2%
To sum up, the principle of curing is: the amount of sufficient curing agent and the amount of appropriate accelerator can make the unsaturated polyester resin cure completely and achieve the desired effect.