Abstract: In the present disclosure, a cutting implement includes a blade body including a base portion and a cutting edge portion connected to an end portion of the base portion. The base portion includes a first metal, and the cutting edge portion includes a second metal and hard particles having a hardness higher than the hardness of the second metal. The hard particles include first hard particles having a particle size of 20 ?m or more and 50 ?m or less.

Abstract: A process for producing 4,4'-dihydroxydiphenyl which comprises subjecting to alkali fusion 1 mol of 4,4'-diphenyldisulfonic acid and/or potassium 4,4'-diphenyldisulfonate together with 4 to 10 mol of potassium hydroxide and 0.1 to 2 mol of potassium sulfate. Alternatively, the process may comprise subjecting to alkali fusion 4,4'-diphenyldisulfonic acid in the presence of potassium hydroxide, controlling to 20 to 25% the potassium hydroxide concentration in the reaction mixture, and separating dipotassium salt of 4,4'-dihydroxydiphenyl.

Abstract: A process for producing 4,4'-diphenyldisulfonic acid is disclosed, which comprises the steps of adding a sulfonating agent to molten diphenyl at a temperature within a range of 130.degree. to 145.degree. C., and when crystallization commences of 4,4'-diphenyldisulfonic acid within such temperature range, cooling the reaction mixture to a temperature within a range of 115.degree. to 127.degree. C., and letting the disulfonation reaction complete while the reaction mixture is maintained within the cooled temperature range. A process for producing monopotassium 4,4'-diphenyldisulfonate is also disclosed, in which steps are taken of adding a sulfonating agent to diphenyl, then controlling the sulfuric acid concentration to 45 to 55%, and while the reaction mixture is heated to at least 140.degree. C., adding at least a stoichiometric amount of a potassium salt of an inorganic acid.