Method of drying copper foil and copper foil drying apparatus

Abstract

A method employed to dry a copper foil having been subjected to various surface treatments, which method comprises irradiating at least one surface-treated side of the copper foil with near infrared rays to dry the copper foil, and an apparatus suitable to the method. The drying of the copper foil having undergone surface treatments can be accomplished by a simple apparatus with low electric power while controlling the heating of the surface of the copper foil so that the drying temperature can be held at 100° C. or higher at which a eutectic alloying of rust preventive metal and copper foil, for example, alloying (brass formation) of zinc and copper on the surface of the copper foil is effected.

what is claimed is:  
     
         1 . A method of drying a copper foil subjected to surface treatments, comprising irradiating one surface or both surfaces of the copper foil with near infrared rays to thereby dry the copper foil.  
     
     
         2 . The method as claimed in    claim 1   , wherein the copper foil is an electrodeposited copper foil.  
     
     
         3 . The method as claimed in    claim 1   , wherein at least one surface-treated side of the copper foil is irradiated with near infrared rays to dry the copper foil.  
     
     
         4 . The method as claimed in    claim 3    wherein nodularization comprising depositing fine particles on the surface of the copper foil is done prior to a passivation.  
     
     
         5 . The method as claimed in    claim 4   , wherein the passivation comprises applying a rust preventive metal.  
     
     
         6 . The method as claimed in    claim 5   , wherein the passivation comprises applying at least one rust preventive metal selected from the group consisting of Zn, Ni, Sn, Cr, Mo and Co.  
     
     
         7 . The method as claimed in any of    claims 1    to    6   , wherein the drying by near infrared irradiation is done under condition such that the surface or surfaces of the copper foil have a temperature of 100 to 170° C.  
     
     
         8 . A copper foil drying apparatus for drying a copper foil subjected to surface treatments, comprising a drying chamber and, arranged therein, a near infrared irradiating unit, said drying chamber adapted to allow the copper foil to be continuously fed therethrough, said near infrared irradiating unit arranged opposite to a surface-treated side of the copper foil so that at least the surface-treated side of the copper foil is irradiated with near infrared rays.  
     
     
         9 . The apparatus as claimed in    claim 8   , wherein the copper foil is an electrodeposited copper foil.  
     
     
         10 . The apparatus as claimed in    claim 8   , which further comprises means for controlling the output of the near infrared irradiating unit so that the surface of the copper foil has a controlled drying temperature.  
     
     
         11 . The apparatus as claimed in any of    claims 8    to    10   , wherein near infrared irradiating units are arranged so that they face each other with the copper foil interposed therebetween, the apparatus provided with control means for selectively operating either a near infrared ray irradiating unit arranged on one side or near infrared irradiating units arranged on both sides in conformity with surface condition of the copper foil fed through the drying chamber.  
     
     
         12 . The method of    claim 1   , wherein said near infrared rays have a wavelength of about 0.8 to 2 μm.  
     
     
         13 . The apparatus of    claim 8   , wherein said near infrared irradiation unit supplies infrared rays having a wavelength of about 0.8 to 2 μm.