(1) Phthalic anhydride is also known as phthalic anhydride, phthalic anhydride, phthalic anhydride, referred to as PA. White needle-shaped crystals or powder with slight odor. Melting point 128 ~ 131℃, boiling point 295℃(sublimation). Low toxicity, LD508000mg/kg. Anhydride equivalent 148, reference pulp 30 ~ 50, suitable period at room temperature for 6h; 100℃/4h; 120℃/1.5h. Curing conditions l00℃/2h+150℃/5h or 100℃/12h or 140℃ /8h or 150℃/6h or 200℃/6h. The thermal deformation temperature of the cured material is 100 ~ 152℃, and the water absorption (24h) is 0.05%.

(2) tetrahydrophthalic anhydride is also known as tetrahydrophthalic anhydride, abbreviated as △ 4-THPA. White crystalline powder. Melting point 103 ~ 104℃(cis isomer). Low toxicity, LD501590mg/kg. Anhydride equivalent 152, reference dosage 55 ~ 65 parts. Curing conditions l40℃/16h or 200℃/1 ~ 2h. The thermal deformation temperature of the cured material is 118℃.

(3) Trimellitic anhydride glyceride, also known as glycerol trimellitic anhydride ester, referred to as TMG(TMTA), white crystal powder. Melting point 65 ~ 75~C. Anhydride equivalent 204, carboxyl equivalent 102, reference dosage 66 to 80 parts. Curing conditions 150~C/lh+180~C/8h or 200~C/8h. The thermal deformation temperature of the cured material is ~220~C.

(4) Polyazelaic anhydride (PAPA), white powder. Melting point 57 ~ 65~C. Viscosity (70~C)800 more than 1000mPa.s, (100~C)300 ~ 700mPa·s. Anhydride equivalent 174, reference dosage 60 to 65 parts, maximum 70 parts. Curing conditions 180℃/4h+200℃/6h or 150℃/17hq--170℃/17h. The thermal deformation temperature of the cured material is 139~C, and the thermal stability is good. The weight loss is less than 1% after thermal aging at 150~C for 8 weeks.

(5) polysebacic anhydride referred to as PSPA, brown wax. Melting point 78~82℃, viscosity (90℃)380~800mPa's. Acid value 603mgKOH/g, reference dosage 60 to 85 servings. Curing conditions 80~C/2h+120~C/2h or 140~C/lh+160℃/2h. The foreign brand is UP - 607.

(6) tung oil anhydride, also known as 308 anhydride, obtained by the reaction of maleic anhydride and tung oil, is a mixture of various structures of anhydride, referred to as TOA, yellow to dark yellow liquid. Viscosity (25℃)5000~6000mPa·s. Low toxicity. The acid value was 110 to 130mgKOH/g, and the reference dosage was 150 to 200 servings. The applicable period is 10 ~ 12d. Curing conditions 80~C/20h or 150~C/4h or 180~C/2h. The curing material has good flexibility, but the thermal deformation temperature is low (70℃), which can be used below 60℃.

(7)647 anhydride cyclopentadiene and maleic anhydride internal or external addition, and contains a small amount of not yet reacted maleic anhydride, therefore, is a low melting point mixed anhydride, Nadic anhydride content of 49% to 56%. White powder or light yellow liquid. Melting point <40~C. Anhydride equivalent 137~147, easy to mix with epoxy resin, reference dosage 60 ~ 80 parts. Curing conditions 100~C/8h or 150--160~C/4h. The thermal deformation temperature of the cured material is 150~C.

(8) Chloroacetic anhydride, also known as hexachloromethyl tetrahydrophthalic anhydride, chlorobridge anhydride, Heite anhydride, referred to as HET, CA, white crystalline powder. Melting point 235 ~ 239~C. Chlorine content 57.1%, non-flammable. Anhydride equivalent 388, reference dosage 100 ~ 110, suitable period (120~C)30min. Curing conditions 100~C/2h+160℃/4h or 120~C/2h+180~C/4h or loo~c/1h+160~0/4h+200~C/lh. The thermal deformation temperature of the cured material is 180~C, and the curing temperature can reach 196~C if 180~C/24h. Due to the high melting point of CA, it is difficult to operate, usually mixed with hexahydrophthalic anhydride 60:40, melting point 85~C, 180~C/20h curing, hot deformation temperature 142~C. It can also be mixed with dodecenyl succinic anhydride, maleic anhydride, methyl nadic anhydride, etc.

(9) Tetrabromophthalic anhydride, also known as tetrabromophthalic anhydride, referred to as TBPA, theoretical bromine content 68.9%, light yellow white powder g o melting point 274 ~ 280℃. Toxic, LD50≥50mg/kg. Reference dosage: 140,150 servings. Curing conditions 120~C/2h+180℃/4h.

(10) Tetrachlorobenzene dimethylacid anhydride, also known as tetrachlorobenzene anhydride, referred to as TCPA, theoretical chlorine content 49.69/5, white crystalline powder. Melting point 255~257~C, boiling point 371℃. The reference dosage is 120 to 130 servings. Curing conditions loo~C/2h+160~C/4h.

(11) Mixed anhydride solid anhydride is not convenient to use, using different varieties and proportions can be prepared liquid anhydride, mixed anhydride, adding a small amount of imidazole, benzyl dimethylamine, DMP-30, etc., can improve heat resistance, water resistance, improve the bonding strength, speed up the curing speed.

(13) Diphenyl ether tetraacid dianhydride (DPEDA), white crystalline powder. The melting point is 222℃, which can be evenly divided in epoxy resin, and can also be mixed with HHPA and MNA curing agent, which has better heat resistance, moisture resistance and flexibility. Anhydride equivalent 155, reference dosage 60 to 75 parts. Curing conditions 120℃/2h+200℃/2h.

(14) Cyclopentyltetraacid dianhydride is also known as cyclopentyltetraacid dianhydride, referred to as CPDA, white crystal. Melting point 212℃. Anhydride equivalent 105, reference dosage 60 ~ 80 parts. Curing conditions 120~C/2h+150℃/1 ~ 2h.

The reaction speed of epoxy resin and polyacid is very slow. It is not used as curing agent because it can not produce high crosslinking degree products. Anhydride because of its long service life; Basically no irritation to the skin; The curing reaction is slow, the heat is small, the shrinkage rate is low, and the heat resistance of the product is high. The product of mechanical strength, excellent electrical properties and other advantages and become an important curing agent. Anhydride is mostly solid, and it is difficult to mix with epoxy resin at room temperature. Therefore, it is often used in a liquid anhydride eutectic mixture at room temperature, or to react anhydride with environmental compounds to generate adducts.

There are many kinds of anhydride curing agent. It is divided into single mixed, simple mixed and eutectic mixed modified anhydride from the use, but the type of modified anhydride is small. From the aspect of chemical structure can be divided into linear aliphatic, aromatic and aliphatic anhydride. From the functional group can be divided into single functional group, pun energy group and multi-functional anhydride, general multi-functional anhydride almost no practical value.

(1) Phthalic anhydride is a more traditional curing agent, the price is cheap, the heat is small when curing epoxy resin adhesive, especially suitable for large casting products, its curing electrical properties and chemical resistance performance is excellent.

(2) Hexahydrophthalic anhydride is obtained by hydrogenation of phthalic anhydride. Its biggest feature is low viscosity after melting, can be made into low viscosity HHPA/ epoxy resin complex, very beneficial to the operation process, and has excellent heat resistance.

(3) Methyl hexahydrophthalic anhydride is colorless and transparent liquid, with long service life, stable color and excellent weather resistance.

(4) Methyl tetrahydrophthalic anhydride is liquid due to isomerization, so its biggest feature is that the viscosity of METHPA/ epoxy resin complex is very low, and it is difficult to crystallize from epoxy resin. It is the most widely used curing agent in anhydride curing agent.

(5) Methyl nadeck anhydride is a liquid anhydride synthesized by methyl cyclopentadiene and maleic anhydride in an equimolar ratio. It is a mixture of cis-trans isomerization and has low viscosity at room temperature.

(6) Pyrophthalic anhydride is a high melting point solid, difficult to dissolve in epoxy resin, because its reaction activity is too high, difficult to operate, usually not used alone.

(7) Although diphenyl ether tetraacid dianhydride is a white crystal with high melting point, its solid powder can be evenly dispersed in epoxy resin, and dissolved in epoxy resin with heating.

(8) Trimellitic anhydride is a white solid with high melting point. Because of its high melting point, it is difficult to cooperate with epoxy resin.

Author: Want to link glue

Link: https://www.jianshu.com/p/424ab151c537

Source: Jane Book

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