Mold Tool and Treatment Method for Mold Tool Surface

Abstract

The average roughness Ra of a mold tool surface that comes into contact with a material to be molded measured for a measurement area 10 μm square or smaller is equal to or lower than 5 nm, and fine granular projection structures having diameters ranging from 10 to 80 nm and heights ranging from 10 to 40 nm are formed on the mold tool surface with a density of 400/μm 2 or higher. The frictional force due to the anchoring effect or the digging effect is reduced, and the adhesive force due to meniscus is also reduced. The release resistance is significantly reduced without affecting the dimensional precision of a fine molded product.

1 . A mold tool that comprises:
 a mold tool surface that comes into contact with a material to be molded, wherein the mold tool surface has:
 an average roughness Ra of 5 nm or less for areas 10 μm square or smaller, and 
 fine granular projection structures with diameters ranging from 10 to 80 nm and heights ranging from 10 to 40 nm with a density of 400/μm 2  or higher. 
   
     
     
         2 . A treatment method for a mold tool surface of a mold tool that comes into contact with a material to be molded, wherein the method comprises:
 irradiating the mold tool surface with a gas cluster ion beam, wherein irradiation fluence of the gas cluster ion beam is controlled such that an average roughness Ra of the mold tool surface measured for an area 10 μm square or smaller decreases, then increases to level off at a certain value as the irradiation fluence increases, and   irradiating the mold tool surface with the gas cluster ion beam in a fluence equal to or higher than the irradiation fluence at the time when the average roughness Ra levels off at the certain value.   
     
     
         3 . The treatment method of  claim 2  that comprises:
 controlling the irradiation fluence of the gas cluster ion beam such that the average roughness Ra is equal to or lower than 5 nm and fine granular projection structures having diameters ranging from 10 to 80 nm and heights ranging from 10 to 40 nm are formed on the mold tool surface with a density of 400/gm 2  or higher.