& nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Epoxy resin adhesive is formulated with epoxy resin as the main component. The end of resin macromolecules has epoxy groups, and there are hydroxyl and ether bonds between chains. During the curing process, hydroxyl and ether bonds continue to be generated, and the structure contains benzene rings and heterocycles. These structures determine that epoxy resin adhesives have excellent properties. Epoxy resin adhesive is a type of adhesive with a long history of use and extremely wide range of applications. One of the outstanding ones is Hangao Letai epoxy resin adhesive. Follow the Ruilangda editor to learn more about it< br />


 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Due to its strength, diversity, and excellent adhesion to a variety of adhesive surfaces, epoxy resin adhesives have gained widespread recognition from users. In recent years, the modification of epoxy resin has been continuously deepened, and the modification methods have been changing rapidly, such as interpenetrating network method, chemical copolymerization method, etc. Especially, liquid crystal toughening method and nanoparticle toughening method have become hot research topics in recent years. With“ Scale up, high purification, refinement, specialization, serialization, and functionalization; The establishment of the development model and the rapid development of research on the modification of epoxy resin have become the focus of attention in the industry, which will promote the further and wider application of epoxy resin in economic construction and people's lives.


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 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Epoxy adhesives with excellent performance are widely used in various fields
 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Adhesive bonding refers to the technique of connecting surfaces of homogeneous or heterogeneous objects together using adhesive. It has the characteristics of continuous stress distribution, light weight, or sealing, and mostly low process temperature. Adhesive bonding is particularly suitable for connecting different materials, thicknesses, ultra-thin specifications, and complex components. Adhesive bonding has developed the fastest in modern times, has a wide range of applications, and has had a significant impact on the progress of high-tech science and technology and the improvement of people's daily lives. Therefore, research, development, and production of various adhesives are very important< br />
Epoxy resin adhesive (abbreviated as epoxy adhesive or epoxy glue) refers to a general term for three-dimensional cross-linked cured compounds that contain two or more epoxy groups in a molecular structure and can be formed under appropriate chemical reagents and conditions< br />


 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Epoxy adhesives are mainly composed of two parts: epoxy resin and curing agent. To improve certain performance and meet different applications, auxiliary materials such as toughening agents, diluents, accelerators, coupling agents, etc. can be added. Due to the high bonding strength and strong versatility of epoxy adhesives, there have been; Universal glue&rdquo& ldquo; Dali glue” It is widely used in fields such as aviation, aerospace, automotive, machinery, construction, chemical industry, light industry, electronics, electrical appliances, and daily life.


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 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Molecular Structure and Variety Classification of Epoxy Adhesives

Epoxy resin is a high molecular weight polymer compound that contains two or more epoxy groups in its molecule and has a relatively low molecular weight. There are many varieties and grades of epoxy resins, but bisphenol A diglycidyl ether epoxy resin, commonly known as bisphenol A epoxy resin, is the most important type. It accounts for 90% of the total production of epoxy resin. Bisphenol A-type epoxy resin, also known as universal epoxy resin and standard epoxy resin, is named E-type epoxy resin in China. It is obtained by the condensation of bisphenol A (BPA or DPP) and epichlorohydrin (ECH) under sodium hydroxide. Depending on the raw material ratio, reaction conditions, and method used, it can be used to produce viscous liquids with low relative molecular weight and high relative molecular weight and high softening point solids with different degrees of polymerization. The average relative molecular weight ranges from 300 to 7000. The appearance is almost colorless or light yellow transparent viscous liquid or flaky brittle solid. Epoxy resin itself is a thermoplastic linear polymer, and when heated, the viscosity of the liquid resin decreases, while the solid resin softens or melts< br />


 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Classified by purpose: universal adhesives, special adhesives, such as high-temperature resistant adhesives (used at a temperature of 150 ℃), low-temperature resistant adhesives (can withstand temperatures of -50 ℃ or lower), strain resistant adhesives (used for attaching strain gauges), conductive adhesives, sealants (used for vacuum sealing and mechanical sealing), optical adhesives (colorless and transparent, resistant to light aging, refractive index matched with optical components), corrosion-resistant adhesives, structural adhesives, etc. It can also be classified according to the type of curing agent, such as amine cured epoxy adhesive, anhydride cured adhesive, etc. It can also be divided into two-component adhesive and single component adhesivePure epoxy adhesive and modified epoxy adhesive.
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 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Performance characteristics of epoxy adhesives

 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Generally, the structure of epoxy resin contains hydroxyl and ether bonds, which give it high adhesion. Due to these polar groups, electromagnetic forces can be generated at adjacent interfaces, resulting in less curing process. Along with the chemical reaction with the curing agent, it can further generate alkyl and ether bonds, which not only have high cohesion but also strong adhesion. Therefore, epoxy adhesives have strong adhesion strength to many materials such as metals, plastics, glass, wood, fibers, etc., commonly known as "ldquo; Universal glue< br />


 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; The presence of stable benzene rings, ether chains, and a dense structure after curing in the epoxy tree structure determines that epoxy adhesives have strong resistance to atmospheric, humid, chemical media, bacteria, and other factors. Therefore, they can be applied in many harsh environments< br />


 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; Universal epoxy resins, curing agents, and additives come from multiple sources, have large production volumes, are easy to prepare, can be contact molded, and can be applied on a large scale. The main disadvantages of epoxy adhesives are: when not toughened, the cured material is generally brittle, and the resistance to peeling, cracking, and impact is poor; Materials with low polarity (such as polyethylene, polypropylene, etc.) have low adhesion. Surface activation treatment must be carried out first; Some raw materials such as reactive diluents and curing agents have varying degrees of toxicity and irritation. When designing the formula, it should be avoided as much as possible, and ventilation protection should be strengthened during construction< br />


 & nbsp;& nbsp;& nbsp;& nbsp;& nbsp;& nbsp; As can be seen from the above, epoxy resin has good comprehensive mechanical properties, especially high adhesion, low shrinkage rate, good stability, and excellent electrical insulation performance. It provides a material basis for adhesives, composite material matrices, powder coatings, and other products.