| 摘要 |
PURPOSE:To improve runnability, surface characteristic and sensitivity by forming a magnetic layer contg. non-film-formable vinyl emulsion gel particles having internally small pores on a base. CONSTITUTION:The magnetic layer contg. the non-film-formable emulsion gel particles having internally small pores is formed on the base, by which the coefft. of friction is decreased and the lubricity, runnability as well as surface characteristic and sensitivity are improved. The non-film-formable vinyl resin emulsion gel particles are formed by pulverizing the non-film-formable emulsion produced by an emulsion polymn. method. Since the particles have internally the small pores, the specific gravity s as low as 0.9-1.1 and the particles are easily concentrated to the surface layer part of the magnetic recording medium. The particles are effective for reforming the surface. The inside of the small pores in the particles may be cavities or may be present with water. The water in the inside evaporates in the stage of drying if the water exists therein. The concn. of the solid content of the non-film-formable vinyl resin emulsion particles is adequately 5-70wt% in general.
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