Patent ID: 7582787

Claim:
Process for manufacturing charge control agent whose active ingredient is a zinc compound of 3,5-di-tert-butylsalicylic acid comprising: dissolving 3,5-di-tert-butylsalicylic acid which is a 2,4-di-tert-butylphenol having a carboxyl group introduced thereto in a sufficient amount of an alkaline aqueous solution to prepare an aqueous solution of 3,5-di-tert-butylsalicylic acid; adding said aqueous solution of 3,5-di-tert-butylsalicylic acid drop by drop to an aqueous solution containing a zinc provider while heating this zinc provider containing aqueous solution; carrying out a reaction between said 3,5-di-tert-butylsalicylic acid and said zinc provider with heating and pH adjustment; said zinc compound being a crystalline zinc 3,5-di-tert-butylsalicylate represented by General Formula (1) below, and having major peaks of X-ray diffraction using the CuKα-characteristic X-ray at Bragg angles 2θ of at least 7.7±0.2° and 15.7±0.2°: in which t-Bu represents a tert-butyl group.