Overview of the hottest epoxy adhesive formulation

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Overview of epoxy adhesives - formulation design 2 components

anhydrides with high heat resistance, such as benzophenone tetraacetic acid dianhydride (BTDA), diphenyl ether tetraacetic acid dianhydride (dpeda), are solids, which are often used in conjunction with alicyclic epoxy resins. The curing temperature is 175 ℃, and the long-term service temperature is -60 ~ 175 ℃. The main disadvantage is that it is brittle, and the fineness and dispersion of the curing agent are not easy to control. After toughening, the service temperature can reach 175 ~ 200 ℃, such as j-30 adhesive. Liquid heat-resistant anhydrides include 70 anhydrides (tetrahydrophthalic anhydride isomer THPA), methyl tetrahydrophthalic anhydride (me313 has plastered composite external insulation system THPA), methyl inner methylene tetrahydrophthalic anhydride (MNA), methyl hexahydrophthalic anhydride (mehhpa), etc

phenolic resin and silicone resin are both curing agents and high temperature resistant modifiers. Usually, low molecular thermosetting phenolic resin (m=350 ~ 450) or thermoplastic phenolic resin (m=500 ~ 650) is used to cooperate with bisphenol A epoxy resin with high relative average molecular weight, and acidic or alkaline accelerators such as 3-hydroxynaphthalic acid, phosphoric acid, Resorcinol, hexamethylenetetramine, DMP-30, benzyl dimethylamine, etc. are added. The curing temperature is 175 ℃, and it can be used for a long time at -60 ~ 260 ℃. The maximum operating temperature can reach 260 ~ 316 ℃. Heat resistance is second only to heterocyclic polymer adhesives. Epoxy phenol formaldehyde adhesive has the advantages of comprehensive performance, high and low temperature resistance, heat aging, atmospheric aging and damp heat aging, and high temperature creep resistance. The main disadvantage is brittleness. The alkoxy group of silicone resin can react with hydroxyl group in epoxy resin. The modifier has the double advantages of epoxy resin and silicone resin

this is the second part of the introduction of high curing agents, such as aromatic amine, aromatic ring or alicyclic anhydride, phenolic resin, silicone resin, dicyandiamide, etc., which are one of the components of high temperature resistant epoxy adhesive. Experts from China epoxy resin industry association also said that other parts of high temperature resistant epoxy adhesive include -

(3) toughening agent. Due to the high rigidity and crosslinking density of macromolecules, high brittleness of high temperature resistant epoxy adhesive affects the bonding strength, especially the line stress strength, so it needs toughening. Commonly used toughening agents include nitrile rubber, polyphenyl oxide resin, polysulfone resin, etc. in the order of positioning, zero position, hammer lifting button. Generally, with the increase of toughness, heat resistance ldquo; The soft and hard environment of Tongling will decline. In recent years, heat-resistant thermoplastic resins such as polysulfone, polyether ketone, polyether ether ketone, etc. have been used to toughen. With the improvement of toughness, the heat resistance basically does not decrease, and even slightly improves

(4) filler. In terms of heat resistance, filler is also an important component. Among them, ultra-fine pure aluminum powder can significantly improve the bonding strength. Gas phase SiO2 and asbestos powder can also control the fluidity and prevent the flow. Common fillers include silica fume, lithopone, etc

(5) antioxidant. Metal ions of the adherend such as copper and iron ions can catalyze the thermal oxidative degradation of organic polymers at high temperatures, causing interfacial bonding damage. In order to eliminate the catalytic degradation activity of metal ions and improve the high temperature resistance, metal ion chelating agents such as 8-hydroxyquinoline, propyl gallate (n-propyl gallate), acetylacetone, catechol and so on are often added. They can capture these metal ions, thereby weakening the catalytic degradation of metal ions. Some oxides of arsenic, manganese and molybdenum can also effectively reduce the activity of metal ions. For example, As2O5 can form very stable iron arsenate with Fe ions

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