Copper clad laminate

Abstract

A copper-clad laminate is prepared by laminating a copper foil on one side or both sides of a polyimide film by thermocompression bonding. The flexibility of the copper-clad laminate is remarkably improved by employing a polyimide film having a thickness of 5 to 20 μm and a copper foil having a thickness of 1 to 18 μm.

1 . A copper-clad laminate prepared by laminating a copper foil on one side or both sides of a polyimide film by thermocompression bonding, wherein
 the polyimide film has a thickness of 5 to 20 μm, and   the copper foil has a thickness of 1 to 18 μm.   
   
   
       2 . The copper-clad laminate as claimed in  claim 1 , wherein
 the polyimide film comprises a heat-resistant polyimide layer and a thermoplastic polyimide layer; and   the copper foil is laminated on one side or both sides of the heat-resistant polyimide layer via the thermoplastic polyimide layer by thermocompression bonding.   
   
   
       3 . The copper-clad laminate as claimed in  claim 1 , wherein the polyimide film has a thickness of 5 to 15 μm. 
   
   
       4 . The copper-clad laminate as claimed in  claim 1 , wherein the copper foil is a rolled copper foil having a thickness of 8 to 18 μm. 
   
   
       5 . The copper-clad laminate as claimed in  claim 4 , wherein the copper foil is a rolled copper foil having a thickness of 10 to 18 μm. 
   
   
       6 . The copper-clad laminate as claimed in  claim 5 , wherein the copper foil is a rolled copper foil having a thickness of 10 to 12 μm. 
   
   
       7 . The copper-clad laminate as claimed in  claim 1 , wherein the copper foil is a rolled copper foil having a tensile strength before heat treatment of 300 N/mm 2  or more, and a ratio of tensile strength after heat treatment at 180° C. for 1 hour as defined by the following equation (1) of 33% or less:
   Ratio of tensile strength after heat treatment(%)=[(tensile strength after heat treatment)/(tensile strength before heat treatment)]×100  (1)   
   
   
       8 . The copper-clad laminate as claimed in  claim 1 , wherein the copper foil is a copper foil with a carrier, in which the copper foil after peeling off the carrier has a thickness of 1 to 5 μm. 
   
   
       9 . A copper-clad laminate prepared by peeling off the carrier from the copper-clad laminate as claimed in  claim 8  and then plating it with copper to a thickness of the copper foil of 5 to 8 μm. 
   
   
       10 . The copper-clad laminate as claimed in  claim 1 , exhibiting MIT folding endurance of about 2000 times or more. 
   
   
       11 . The copper-clad laminate as claimed in  claim 9 , exhibiting MIT folding endurance of about 2000 times or more. 
   
   
       12 . The copper-clad laminate as claimed in  claim 1 , wherein the polyimide film is a thermocompression-bonding multilayer polyimide film having a thermoplastic polyimide layer on one side or both sides of a heat-resistant polyimide layer. 
   
   
       13 . The copper-clad laminate as claimed in  claim 12 , wherein polyimide particles are dispersed in the thermoplastic polyimide layer. 
   
   
       14 . The copper-clad laminate as claimed in  claim 13 , wherein the thermoplastic polyimide layer has polyimide particles with a median size of 0.3 to 0.8 μm and the maximum size of 2 μm or less dispersed within at least a depth of 0.5 μm from its surface in a ratio of about 0.5 to 10% by weight relative to the polyimide in the polyimide surface layer, and is substantially free from an inorganic powder, and
 the polyimide film has a friction coefficient of 0.05 to 0.7.   
   
   
       15 . The copper-clad laminate as claimed in  claim 13 , wherein the polyimide particles are prepared from a pyromellitic acid component and a p-phenylenediamine component. 
   
   
       16 . The copper-clad laminate as claimed in  claim 12 , wherein the polyimide film comprises a thermoplastic polyimide layer with a thickness of 1 to 6 μm on both sides of a heat-resistant polyimide layer with a thickness of 3 to 18 μm. 
   
   
       17 . The copper-clad laminate as claimed in  claim 12 , prepared by laminating the thermocompression-bonding multilayer polyimide film and the copper foil by thermocompression bonding under pressure at a temperature of a glass transition temperature of the thermoplastic polyimide to 400° C. both inclusive. 
   
   
       18 . The copper-clad laminate as claimed in  claim 12 , wherein the thermocompression-bonding multilayer polyimide film is formed by disposing a thermocompression-bonding polyimide layer on one side or both sides of a heat-resistant polyimide layer and integrating them by coextrusion-flow casting method. 
   
   
       19 . The copper-clad laminate as claimed in  claim 1  used for a whole polyimide hinge. 
   
   
       20 . A copper-clad laminate prepared by laminating a copper foil with a thickness of 18 μm or less on a thermocompression-bonding multilayer polyimide film with a thickness of 5 to 25 μm, wherein
 the thermocompression-bonding multilayer polyimide film has a thermoplastic polyimide layer, in which polyimide particles are dispersed, on at least one side of a heat-resistant polyimide layer.   
   
   
       21 . A process for continuously manufacturing a copper-clad laminate by laminating a copper foil with a thickness of 1 to 18 μm on a polyimide film with a thickness of 5 to 20 μm, which has a thermoplastic polyimide layer on one side or both sides of a heat-resistant polyimide layer, by thermocompression bonding, comprising:
 continuously feeding the polyimide film and the copper foil into a laminating machine such that the copper foil is disposed on the thermoplastic polyimide layer of the polyimide film; and   laminating them by thermocompression bonding under pressure at a temperature of a glass transition temperature of the thermoplastic polyimide to 400° C. both inclusive.