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US 4,438,254 AGranted
Process for producing epoxy resins
AssigneeThe Dow Chemical Company
InventorsGeorge A. Doorakian, Marsha A. Paul
Life of this patent
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Abstract
An improved process for reacting vicinal epoxides with phenols or thiophenols is described. This process is conducted at essentially anhydrous conditions and temperatures less than 175.degree. C. The resulting resins are generally more linear and less colored than advanced resins produced via prior art processes. Also the phosphonium catalyst remains active to promote subsequent advancement or curing reactions. The catalyst can be deactivated in a separate step to produce a resin of exceptional purity.
Claims20
In a process for preparing an advanced epoxy resin by reacting
- (a) a compound bearing an average of more than one vicinal epoxide group per molecule with
- (b) a polyhydric phenol or thiophenol, in the presence of a catalytic amount of a tetrahydrocarbyl phosphonium salt,
- the improvement wherein the reaction is conducted at a temperature less than about 175.degree. C. and in an essentially anhydrous medium.
Dependencies are inferred from the claim text.