Hello! What do you know about phenolic epoxy resins? Is there a big difference between its expansion

The expansion coefficient of epoxy resin is related to the cross-linking density after curing, and it is generally believed that the higher the cross-linking density after curing, the smaller the expansion coefficient and the better the dimensional stability. Therefore, the expansion coefficient of the cured products of different epoxy resins and different curing agents is different. Bisphenol A epoxy resin molecule contains two functional groups, and linear multifunctional phenolic epoxy resins include phenol linear phenolic epoxy resin (EPN) and o-cresol linear phenolic epoxy resin (ECN).

ERN usually uses linear phenolic epoxy resins with an average degree of polymerization of 3 5, and ECN usually uses a slightly higher average degree of polymerization, between 3 7. Therefore, the cured phenolic epoxy resin has a higher cross-linking density than the bisphenol A epoxy resin, and theoretically the linear expansion coefficient is smaller. However, in the actual application, it has a great relationship with the selection of curing agent and the whole formula system, if the curing agent and formula design are reasonable, the expansion coefficient of phenolic epoxy resin curing product is slightly lower.

The expansion coefficient of products produced by different companies is different. You follow your actual requirements for the query. For example, Sumitomo Bakelite produces the same expansion ratio as the epoxy resin for injection (KE-4200) produced by Kyocera Chemical.

Hello Prophilic oxy resins are usually composed of an epoxy resin body and a curing agent, in which both non-melt matter and bisphenol A may be present in the epoxy resin. Generally speaking, non-meltable abrasive material refers to the solid substance in the epoxy resin that is not completely dissolved, which may have a certain impact on the performance and quality of the epoxy resin due to the impurities in the raw materials and production process. Bisphenol A is a commonly used curing agent in epoxy resins, which can improve the performance of epoxy resins after curing, but bisphenol A is also considered to be a chemical that may be harmful to human health.

Therefore, in the production and use of epoxy trees, it is necessary to strictly control the content of incontaminated matter and bisphenol A, and take corresponding measures to reduce its potential harm to the environment and human body. Hope mine is helpful to you. If you have any further questions, please feel free to ask me.

The molecular structure of bisphenol A epoxy resin determines its properties with the following characteristics:

1) It is a thermoplastic resin, but it has thermosetting, and can form a variety of cured products with excellent performance with a variety of curing agents, catalysts and additives, which can meet almost all kinds of use requirements.

2) The manufacturability of the resin is good. Basically no small molecule volatiles are produced during curing, and can be molded at low pressure, and can be dissolved in a variety of solvents.

3) The cured material has high strength and bonding strength.

4) The cured material has high corrosion resistance and electrical properties.

5) The cured material has certain toughness and heat resistance.

6) The main disadvantages are: heat resistance and toughness are not high, and damp heat resistance and weather resistance are poor.

Bisphenol a Epoxy resins

Also known as E-type epoxy resin, the chemical name is bisphenol A diglycidyl ether, referred to as EP, with an average molecular weight of 3100 7000. Almost colorless or light yellow transparent viscous liquid or brittle solid in the form of lumps (flakes, granules) with relative density. Soluble in acetone, forma.

Ethyl ketone, cyclo-leased ketone, ethyl acetate, toluene, xylene, anhydrous ethanol, ethylene glycol and other organic solvents. Combustible. Innocuity.

It is used as a tackifier for polysulfide sealants and a tackifier for chlorosulfonated polyethylene adhesives. It is also used as a reinforcing agent for polyurethane adhesives, and the shear strength of polyurethane epoxy adhesives is 76% higher than that of simple polyurethane adhesives. The addition of a small amount of epoxy resin to the two-component polyurethane adhesive can significantly improve the high shear strength of the polyurethane adhesive.

Compared with bisphenol A epoxy resin, phenolic epoxy resin contains more than two epoxy groups in the molecular structure, and the crosslinking density is high after curing, and the heat resistance, solvent resistance, chemical resistance and dimensional stability of the product will be relatively improved. However, the brittleness of the product increases, and the adhesion to the copper foil decreases.

Phenolic epoxy resin belongs to multifunctional epoxy resin because it contains more than 2 epoxy groups in its molecular structure.

O-cresol phenolic epoxy resin is basically the same as phenol phenolic epoxy resin, except that there is a methyl group in the ortho position of the benzene ring, which is better than the former in terms of water resistance and melt viscosity.

Compared with the traditional phenolic epoxy resin, bisphenol A phenolic epoxy resin not only has higher heat resistance of the cured product, but also has good comprehensive properties after curing with diaminodiphenyl sulfone (DDS) with a TG of 224.

There are many types of epoxy resins, and for the sake of distinction, the names of different monomers are often added in front of the epoxy resin. For example, diphenol propane (referred to as bisphenol A) epoxy resin (prepared from bisphenol A and epichlorohydrin); glycerol epoxy resin (made from glycerol and epichlorohydrin); butene epoxy resin (oxidized from polybutene); Cyclopentadiene epoxy resin (prepared from dicyclopentadiene epoxidation). In addition, for the same type of epoxy resin, they are also divided into different grades according to their viscosity and epoxy value, so their properties and uses are also different.

At present, the most widely used are some grades of bisphenol A epoxy resin, which is usually referred to as bisphenol A epoxy resin.

It is the largest and most widely used variety of epoxy resin, because it has high transparency, and it is also formed by the reaction of bisphenol A and epichlorohydrin in the presence of sodium hydroxide: where n: n is generally between 0 25.

According to the relative molecular mass, epoxy resins can be divided into various types. Generally, the average value of n of low relative molecular weight epoxy resin is less than 2, and the softening point is less than 50, which also becomes a soft epoxy resin; The n value of the medium relative molecular weight epoxy resin is between 2 5, and the softening point is between 50 95. Resins with n greater than 5 (softening point above 100) are called high relative molecular weight resins. Bisphenol A epoxy resin is commonly used in the field of corrosion protection in several forms:

Epoxy coatings.

Epoxy resin fiberglass.

Epoxy resin cement, mortar.

Epoxy monolithic flooring.

Epoxy-phenolic, epoxy-furan resin composite FRP.