Copper clad laminate
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, 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, wherein the thermoplastic polyimide layer comprises a thermoplastic polyimide and polyimide particles with a median size of 0.3 to 0.8 μm and a maximum size of 2 μm or less dispersed within at least a depth of 0.5 μm from a surface of the thermoplastic polyimide layer in a ratio of about 0.5 to 10% by weight relative to the thermoplastic polyimide in the thermoplastic polyimide layer, wherein the polyimide particles are prepared from pyromellitic acid component and p-phenylenediamine component.
2. The copper-clad laminate as claimed in claim 1 , wherein the polyimide film has a thickness of 5 to 15 μm.
3. 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.
4. The copper-clad laminate as claimed in claim 1 , wherein the copper foil is a rolled copper foil having a thickness of 10 to 18 μm.
5. The copper-clad laminate as claimed in claim 1 , wherein the copper foil is a rolled copper foil having a thickness of 10 to 12 μm.
6. 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 461 N/mm 2 or less, and a ratio of tensile strength after heat treatment at 180° C. for 1 hour as defined by the following equation (1) of 19% or more and 33% or less,
Ratio of tensile strength after heat treatment (%)=[(tensile strength after heat treatment)/(tensile strength before heat treatment)]×100 (1).
7. 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.
8. A copper-clad laminate prepared by peeling off the carrier from the copper-clad laminate as claimed in claim 7 and then plating it with copper to a thickness of the copper foil of 5 to 8 μm.
9. The copper-clad laminate as claimed in claim 1 , exhibiting MIT folding endurance of about 2000 times or more.
10. The copper-clad laminate as claimed in claim 8 , exhibiting MIT folding endurance of about 2000 times or more.