Epoxy resin, phenolic resin and unsaturated polyester resin are known as the three common thermosetting resins. They are the largest and most widely used types of thermosetting resins. Epoxy resin contains a unique epoxy group, as well as light and ether bonds and other active groups and polar groups, and thus has many excellent performance. Compared with other thermosetting resins, the types and grades of the epoxy resin are the most, and the properties of the epoxy resin are different. The type of epoxy resin curing agent is more, plus a number of accelerators, modifiers, additives, etc., can be a variety of combinations and groups. To obtain a variety of excellent performance, with different characteristics of the epoxy curing system and curing products. Can adapt to and meet the requirements of different performance and process performance. This is beyond the other thermosetting resins.

    1, Epoxy resin and the properties of cured products

    (1) High mechanical properties. Epoxy resin has strong cohesive force and dense molecular structure, so its mechanical properties are higher than that of phenolic resin and unsaturated polyester resin.
    (2) Excellent adhesive properties. Epoxy resin curing system, the active epoxy group, hydroxyl and ether bond, amine bond, ester bond and other polar groups to give epoxy curing material with high bonding strength. In addition, it has a high cohesion strength and other mechanical properties, so it is particularly strong bonding performance, can be used as structural adhesive.
    (3) Curing shrinkage rate is small. Generally 1% ~ 2%. Is one of the lowest curing shrinkage rate of thermosetting resin (PF resin is 8% ~ 10%; unsaturated polyester resin is 4% ~ 6%; silicone resin is 4% ~ 8%). Linear expansion coefficient is very small, generally 6 x 10-5/. So its product size is stable, the internal stress is small, not easy to crack.
    (4) Good craft. When the epoxy resin is cured, it can not produce low molecular volatile matter, so it can be formed by low pressure or contact pressure. The flexibility of the formula design is very large, can be designed for a variety of technical requirements of the formula.
    (5) Good electrical performance. Is one of the best varieties of thermosetting resins.

    (6) Stability is good. Non alkali, salt and other impurities of the epoxy resin is not easy to degenerate. As long as the storage properly (sealed, not affected with damp, high temperature), the storage period of 1 years. If the inspection can be used over time. Epoxy resin has excellent chemical stability. The performance of alkali, acid, salt and other corrosive medium is better than that of unsaturated polyester resin, phenolic resin, thermosetting resin.
    (7) The heat resistance of the cured epoxy resin is generally 80 to 100. Epoxy resin heat-resistant varieties up to 200 degrees Celsius or higher.
    (8) The best comprehensive properties of the epoxy resin and its cured products in the hot lie resin.

    2, Epoxy resin application characteristics

    (1) The flexibility and diversity of the formulation design. According to the different use of performance and process performance requirements, design the best targeted formula. This is one of the major characteristics and advantages of the application of epoxy resin. But each of the best formulations have a certain scope of application (conditions), not in any process conditions and any use of the conditions are appropriate to use. That is, there is no "universal" the best formula. Must be designed according to different conditions, the best formula. Due to different curing system of epoxy resin curing system is not exactly the same, so the curing process of epoxy resin, that is, the curing process conditions on the structure and properties of epoxy curing material greatly. The same formula in different curing process conditions the performance of the resulting product will be very large difference. So the correct way to make the best material formula design and process design is the key to the application of epoxy resin, but also the secret of the technology. Must be able to produce and develop their desired properties of the epoxy material, it must be designed to the corresponding special formula and its molding process conditions. Therefore, it is necessary to understand and master the structure and properties of epoxy resin and its curing agent, modifier, and the reaction mechanism between them and the influence on the structure and properties of the cured epoxy resin. So as to be handy in the material formulation design and process design, ease of use, to obtain the best solution, the production and development of the best performance, cost lowest epoxy materials and products.

    (2) Different curing system of epoxy resin respectively in the low temperature, room temperature, temperature or high temperature curing, in the wet surface even in water curing, fast cure, also can slow curing, so its adaptability to the requirements for construction and manufacture technology of the strong. Epoxy resin can be low pressure molding or contact pressure molding, so it can reduce the requirements of molding equipment and tooling, reduce investment, reduce costs.
    (3) In the three general types of thermosetting resins, the price of the epoxy resin is high, so it is affected by the application. However, due to its excellent performance, it is mainly used for occasions with high performance requirements, especially in the field of high performance requirements.