Anhydride phtalique

Phthalic anhydride, also known as phthalic anhydride, is an important organic chemical raw material, a general-purpose anti-scorching agent for natural rubber, isoprene rubber, smooth-butadiene rubber, styrene-butadiene rubber, and nitrile rubber, which prevents scorching and improves operational safety. It has little effect on the positive vulcanisation time and the aging performance of the products. Particularly effective in systems containing thiazole-guanidine and thiazole-tyulam accelerators and rubbers equipped with alkaline accelerators, but not applicable to tyulam sulphur-free vulcanisation systems. Easily dispersed, no spraying frost, not too polluting, but there is also a slight discolouration when white rubber is exposed to light, generally should not be used for white rubber. Phthalic anhydride and sodium carbonate together for high promotion sponge products rubber, can increase the foaming effect. Phthalic anhydride's greatest use is as an organic intermediate in the production of plasticisers, coatings and unsaturated polyester resins. Phthalic anhydride is also a widely used curing agent for anhydride-based epoxy resins. It is inexpensive, has low heat generation during curing, and is particularly suitable for large cast products and laminates. The cured material has good electrical properties and mechanical strength, drug resistance is also good (but alkali resistance is poor), heat distortion temperature of 110 ~ 147 ℃. General dosage of 30 ~ 50 parts, curing conditions: 100 ℃ / 2h +150 ℃ / 5h. This product has a high melting point, sublimation, shorter service life (110 ℃ under 3.5h).

Appearance is white needle crystal, relative density is 1.527, melting point is not less than 131.61℃, boiling point 295.1℃. Can sublimate. Soluble in acetone, ethanol, slightly soluble in benzene and ether, insoluble in gasoline and water. It is converted to phthalic acid when it meets boiling water or acts with water for a long time. Stable in storage. Combustible. Dust-air mixtures are explosive, the lower limit of burning mass concentration is 12.6g/cm3.Deposited dust is a fire hazard. Aerosol combustion temperature 160°C, auto-ignition temperature 545°C. Toxic, limit allowable mass concentration 1mg/m3.

Phthalic anhydride is one of the most important organic chemical raw materials, its main derivatives are dibutyl phthalate, dioctyl ester and diisobutyl ester, etc., which are used as plasticisers for PVC, etc.; it can also be used in the production of unsaturated polyester resins, alkyd resins, dyestuffs and pigments, a variety of paints, food additives, phenolphthalein, a laxative in medicine, and imidacloprid, moclobemide, as well as sodium saccharin in pesticides.

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