The role of accelerators in unsaturated resin formulations
The role of accelerators in unsaturated resin formulations
1. The Function and Mechanism of Accelerators
Accelerator is an additive in unsaturated resin formulations, mainly aimed at improving the performance of unsaturated resins, increasing curing speed and hardness, and improving the heat resistance and chemical stability of products. There are many types of accelerators, which can be divided into the following categories based on their mechanism of action:
(1)Peroxides: formyl peroxide (PM), acetyl peroxide (PA), benzoyl peroxide (BP), etc. Peroxide type accelerators are the most commonly used type, which can improve the reaction activity of unsaturated resins and thus shorten the curing time. This type of promoter will decompose when heated or oxygen is introduced, generating free radicals, which in turn trigger the reaction.
(2) Epoxy class: epoxy propane (EP), epoxy ethoxypropane (EEP), epoxy propylene oxide methane (EBP), etc. Epoxy accelerators are often used to improve the chemical stability of products, as well as to enhance the hardness and heat resistance of unsaturated resins. Due to the presence of active oxygen atoms in epoxy compounds, they can react with double bonds in unsaturated resins to form stable compounds, thereby improving product performance.
(3)Metal salts: cobalt series and manganese series metal salts, etc. The mechanism of action of metal salt accelerators is similar to that of peroxides. They can also accelerate the curing process of unsaturated resins, improve the hardness and heat resistance of products.
2. Types and usage methods of accelerators
There are certain differences in the application of different types of accelerators in unsaturated resin formulations, and the following points should be noted when using them:
(1)Peroxides: Due to their susceptibility to thermal decomposition, appropriate stabilizers such as p-hydroxybenzoic acid should be added during use to extend their shelf life.
(2)Epoxy: Mainly used to improve the chemical stability of products, therefore, when using unsaturated resin formulas, its dosage should be controlled. Excessive use can affect the physical and mechanical properties of the product.
(3)Metal salts: When using, attention should be paid to mastering the concentration of metal salts and heating temperature, in order to fully exert their promoting effect.
In summary, accelerators are an important component in unsaturated resins, which can significantly improve the performance of unsaturated resins, improve the durability and chemical stability of products. There are various types of accelerators, and it is necessary to choose suitable accelerators according to different needs, and pay attention to the usage methods and precautions in order to achieve the best results. ——
