Thermoplastic polyimide composition and double-sided flexible copper clad laminate using the same

Abstract

A thermoplastic polyimide composition characterized by improved thermal resistance, adhesion and flatness for use in copper clad laminates. The polyimide contains repeating units represented by the formulae I and II,

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a cross section showing a conventional method for making an adhesiveless double-sided copper clad laminate;

FIG. 2 is a cross section showing another conventional method for making an adhesiveless double-sided copper clad laminate;

FIG. 3 is a cross section showing a further conventional method for making an adhesiveless double-sided copper clad laminate; and

FIG. 4 is a cross section showing a method for making an adhesiveless double-sided copper clad laminate according to a preferred embodiment of the invention.

Claims

1. A thermoplastic polyimide composition, comprising: a thermoplastic polyimide copolymer having repeating units represented by formulae I and II, and the mole fraction of the repeating unit of formula I being at least 10%,

2. The thermoplastic polyimide composition as claimed in claim 1, wherein each of Ar1 and Ar2, independently, represents at least one of the bivalent aromatic groups specified below:

3. The thermoplastic polyimide composition as claimed in claim 1, wherein X represents at least one of the quadrivalent aromatic groups specified below:

4. The thermoplastic polyimide composition as claimed in claim 1, wherein the thermoplastic polyimide copolymer has a glass transition temperature (Tg) of about 210-300° C.

5. The thermoplastic polyimide composition as claimed in claim 1, wherein the thermoplastic polyimide copolymer has a glass transition temperature (Tg) of about 230-280° C.

6. The thermoplastic polyimide composition as claimed in claim 1, wherein the mole fraction of the recurring unit of formula I is about 10-90%, and the mole fraction of the recurring unit of formula II is about 90-10%.

7. The thermoplastic polyimide composition as claimed in claim 1, wherein the thermoplastic polyimide copolymer exhibits an intrinsic viscosity (I.V.) not less than 0.75 dl/g.

8. The thermoplastic polyimide composition as claimed in claim 1, further comprising an inorganic additive.

9. The thermoplastic polyimide composition as claimed in claim 1, wherein the inorganic additive comprises at least one of silica, talc, calcium carbonate, and clay.

10. A double-sided flexible copper clad laminate, comprising: a first polyimide film and a second polyimide film, sandwiched between two copper foils, whereinthe first polyimide film has a lower thermal expansion coefficient than the second polyimide film; andthe second polyimide film comprising the thermoplastic polyimide composition of claim 1.

11. The double-sided flexible copper clad laminate as claimed in claim 10, wherein the second polyimide film has a thickness of about 3-5 μm.

12. The double-sided flexible copper clad laminate as claimed in claim 10, wherein a bulk thermal expansion coefficient of the first and second polyimide films is less than 30 ppm/° C.