Epoxy resin refers to a general term for a class of polymers containing more than two epoxy groups in the molecule. It is a polycondensation product of epichlorohydrin and bisphenol A or polyol. Due to the chemical activity of epoxy groups, a variety of compounds containing active hydrogen can be used to open the ring, curing crosslinking to generate a network structure, so epoxy resin is a thermosetting resin. Epoxy resins not only have large output and rich varieties, but new modified varieties are still increasing.
Due to the advantages of rich variety and superior physical and chemical properties, epoxy resins are widely used in coatings, adhesives and electronic appliances.
- Adhesives: Epoxy resin has become the mainstream product in the field of adhesives due to its strong adhesion to a variety of materials. There are many kinds of adhesives made of epoxy resin, which have the advantages of heat resistance, water resistance, corrosion resistance, excellent insulation and strong binding force with matrix. At present, epoxy resin adhesives have been widely used in construction, automotive, aerospace, water conservancy and other fields. For example, water-based epoxy adhesives are adhesives made from water-based epoxy resins. Compared with other epoxy resin adhesives, waterborne epoxy adhesives are non-toxic, tasteless, non-flammable, easy to use and other advantages, so as a widely used epoxy resin adhesive. Water-based epoxy adhesives can be used in automotive structures for the elastic bonding of lighting devices, weather strips, fiberglass composites, metal and plastic parts, etc., as well as in the construction field for the bonding of granite concrete, metal, sand and rubber, etc.
Figure1. Epoxy adhesive is used for assembly of auto parts
- Coating: Epoxy resin is widely used in the coating field due to its excellent adhesion, good corrosion resistance and strong wear resistance. Currently, applications of epoxy coatings include pipeline protection for petroleum, natural gas and water, coating of components and coating structures for wood, construction and machinery. For example, epoxy resin based two-component waterborne polyurethane prepared from water-based epoxy polyols and polyisocyanates is an epoxy resin coating with low film forming temperature, strong adhesion, good wear resistance, high hardness and strong corrosion resistance. It is mainly used for the protection of various wood products.
Figure 2.The structure of epoxy based two-component waterborne polyurethane coatings
- Electronic appliances: Epoxy resin has good corrosion resistance, excellent dimensional stability, high insulation and greater strength, so it has been widely used in the field of electronic appliances. Its applications in the field of electronics and appliances include power mutual inductance, integrated circuits, copper clad laminates, insulation packages and conductive adhesives. For example, epoxy aluminum coated graphite composites can be obtained by blending epoxy resin with aluminum coated graphite flakes. The thermal conductivity of the material has been greatly improved, and the electric volume resistivity is much higher than that of epoxy resin and graphite composites, so it can be used as an electrical insulating material with high thermal conductivity.
Figure 3. Epoxy resins can be used to prepare high thermal conductivity electrical insulating materials
According to the chemical structure, epoxy resins can be divided into five categories: glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, alicyclic epoxy resin, and epoxide olefins epoxy resin.
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