Patent ID: 7989522

Claim:
A process of producing a wax composition comprising a microcrystalline wax, polyisoprene rubber or natural rubber as a polymer, and a filler, said process comprising: kneading the microcrystalline wax and the polymer to prepare a wax/polymer composition comprising 50-95% by weight of the microcrystalline wax and 5-50% by weight of the polymer, wherein said kneading comprises a first kneading substep to prepare a masterbatch comprising 5% to 45% by weight of the microcrystalline wax and 55% to 95% by weight of the polymer, and a second kneading substep in which an additional amount of the microcrystalline wax is added to the masterbatch followed by further kneading; and kneading a filler into the wax/polymer composition; wherein the first kneading substep is carried out by kneading the microcrystalline wax and the polymer at a temperature lower than the melting completion temperature of the microcrystalline wax, the first kneading substep is carried out by putting the whole amount of the polymer in a kneader all at once and then adding the microcrystalline wax thereto in divided portions, and the second kneading substep is carried out by putting the whole amount of the masterbatch in a kneader all at once and then adding the microcrystalline wax thereto in divided portions.