Introduction to epoxy resins

epoxy resin is an organic polymer compound with two or more epoxy-based groups in a general lym, and its relative molecular mass is not high except for a fewThe molecular structure of epoxy resin is characterized by the active epoxy group contained in the molecular chain, which can be located at the end, middle or ring structure of the molecular chainBecause the molecular structure contains active epoxy-based groups, so that they can interact with many types of curing agents to form an insoluble, unmelted polymer with a three-way mesh structure★ epoxy resin's properties and properties1, in various formsA variety of resins, curing agents, modifiers system can be almost adapted to a variety of applications of the form of the requirements, the range can be from very low viscosity to high melting point solids2, curing is convenientWith a variety of curing agents, epoxy resin systems can be cured in a temperature range of 0 to 180 degrees C3, strong adhesion forceThe presence of polar hydroxyl and ether bonds inherent in the cyclosine molecular chain makes it highly adhesion to various substancesEpoxy resins are cured with low shrinkage and low internal stress, which also helps to increase adhesion strength4, low shrinkageThe reaction of epoxy resins and the curing agents used is carried out by directly adding reactions or open-loop polymerization reactions of epoxy-based elements of resin molecules, without water or other volatile by-products releasedCompared with unsaturated polyester resins and phenolic resins, they show very low shrinkage (less than 2%) during curing5, mechanical propertiesThe cured epoxy resin system has excellent mechanical properties6, electrical performance The cured epoxy resin system is a kind of excellent insulation material with high dielectric properties, surface leakage and arc resistance 7, chemical stability In general, the cured epoxy resin system has excellent alkaline, acid and solvent resistance Like other properties of the curing epoxy system, the chemical stability depends on the resin and curing agent selected The proper selection of epoxy resins and curing agents can give them special chemical stability 8, dimensional stability The synthesis of many of the above properties makes the epoxy system with outstanding dimensional stability and durability 9, mold-resistant The cured epoxy system is resistant to most molds and can be used in harsh tropical conditions ★ according to the molecular structure, epoxy resin can be divided into five main categories: 1, shrinking glycerin epoxy resin
2, shrinking glycerides epoxy resin
3, shrinking glycerides epoxy resin
4, line-type fatty body epoxy resin
5, lipid ring-type epoxy resin composite materials industry the largest use of epoxy resin varieties is the first type of shrunken glycerin ether epoxy resin, and in turn to diphenol-based propane epoxy resin (referred to as Bisphenol A type epoxy resin) The second is shrinking glyceride epoxy resin 1, shrinking glycerin ether epoxy resin shrinkgy ether epoxy resin is composed of phenolic or alcohol-containing phenols or alcohols with epoxy chloropropane (1) diphenol-based propane epoxy resin diphenol-propanpropreoin is made up of diphenol-based propane and epoxy chloropropane industrial diphenol-based propane epoxy resins are actually a mixture of molecules with different polymerization sylcoping degrees Most of these molecules are line-shaped structures that contain two epoxy-based ends A small number of molecules may be subserified, and the very few molecules terminate the group is a chlorol group rather than an epoxy Therefore, the epoxy content of epoxy resin, chlorine content and so on on the curing and curing properties of the resin has a great impact The control index as a resin in industry is as follows: (1) epoxy value The epoxy value is the most important index to identify the properties of epoxy resin, and the industrial epoxy resin model is distinguished by the different epoxy values The epoxy value is the amount of epoxy-based substance per 100g resin The inverse of the epoxy value multiplied by 100 is called epoxy equivalent The meaning of epoxy equivalent is the number of grams of epoxy resin containing 1mol epoxy (2) inorganic chlorine content The chlorine ions in the resin can be used in cooperation with amine curing agent sedritants to affect the curing of the resin, but also affect the electrical properties of the curing resin, so the chlorine content is also an important index of epoxy resin (3) organochlorine content The organic chlorine content in the resin indicates the content of the chlorine group in the molecule that does not have a closed-loop reaction, and its content should be reduced as much as possible, otherwise it will also affect the curing and the performance of the resin (4) swing points (5) viscosity or softening point (2) phenolic poly-epoxy poly-epoxy resin syltenating includes phenolic formaldehyde type, para-phenolform-type polyoxyresin, compared with diphenol-based propane-type epoxy resin, the on-line molecule contains more than two epoxy base, so the cross-linking density of the product after curing, with excellent thermal stability, mechanical properties, electrical insulation, water resistance and corrosion resistance They are made up of a glutaphenol resin and epoxy chloropropane (3) Other polyhydroxyphenol-shrinking glycerin epoxy resins are useful in such resins as: mephephenol-type epoxy resin, mephephenol-formaldehyde epoxy resin, tetraphenol-ethane-type epoxy resin and tri-triamcinolone Hydroxyl methane-type epoxy resin, these multi-functional glycerin ether resin after curing has a high thermal deformation temperature and rigidity, can be alone or mixed with the general E-type resin, for high-performance composite materials (ACM), printing circuit boardandand and other substrate materials (4) lipid polyol shrinkglyceride glycerin ether-type polyol-shrinkgy glycol-shrinking glycol ether moleculecontains contains two or more epoxy-based, the majority of this resin is very low viscosity; 2, other types of epoxy resin (1) shrinkgies triglyceride epoxy resin shrinkgies and diphenol-based propane epoxy resin comparison, it has low viscosity, good use of process; Have a better surface gloss, light transmission, good climate resistance (2) shrinkgy trilycemine epoxy resin sin such resins are the advantages of multi-capacity, high epoxy equivalent, cross-linking density, heat resistance significantly improved Prior to the domestic and foreign has used the shrinking glyceride epoxy resin superior adhesion and heat resistance to manufacture carbon fiber-reinforced composite materials (CFRP) for aircraft secondary structural materials (3) Epoxy resins such as lipid cyclocyclic epoxy resins are produced by epoxy of the bi-bonds of lipocyclic olefins by epoxidation, their molecular structure and diphenol-based propane epoxy resins and other epoxy resins are very different, the former epoxy syltos are directly connected to the lipid ring, and the latter epoxy is connected to the hyenium or fatty hydrocarbons with epoxy-based ether The curing material of the li-cyclocyclate epoxy resin has the following characteristics: (1) high compression and tensile strength, (2) long-term burst can still maintain good mechanical properties under high temperature conditions, (3) arc resistance, UV-resistant aging properties and good weather resistance (4) the molecular structure of the adipose epoxy resin is not only benzene-free, but also non-fat ring structure Only the fat chain, the epoxy is connected to the fat chain The strength, toughness, adhesion and resistance to positive and negative temperature sin sin are good after curing