Laminate for printed wiring board
View Patent ↗A laminate for a printed wiring board having a laminate structure comprising an electrical insulator layer (A) and an electrical conductor layer (B) bonded directly to each other, wherein the electrical insulator layer (A) is formed of a fluorocopolymer comprising repeating units (a) based on tetrafluoroethylene and/or chlorotrifluoroethylene, repeating units (b) based on a fluoromonomer excluding tetrafluoroethylene and chlorotrifluoroethylene, and repeating units (c) based on a monomer having an acid anhydride residue and a polymerizable unsaturated bond in amounts of (a) being from 50 to 99.89 mol %, (b) being from 0.1 to 49.99 mol % and (c) being from 0.01 to 5 mol %, based on ((a)+(b)+(c)), and the electrical conductor layer (B) has a surface roughness of at most 10 μm on the side being in contact with the electrical insulator layer (A). The laminate for a printed wiring board is excellent in signal response in a high frequency region.
1. A laminate for a printed wiring board having a laminate structure comprising an electrical insulator layer (A) and an electrical conductor layer (B) bonded directly to each other, wherein the electrical insulator layer (A) is formed of a fluorocopolymer comprising repeating units (a) based on tetrafluoroethylene and/or chlorotrifluoroethylene, repeating units (b) based on a fluoromonomer excluding tetrafluoroethylene and chlorotrifluoroethylene, and repeating units (c) based on a monomer having an acid anhydride residue and a polymerizable unsaturated bond in amounts of (a) being from 50 to 99.89 mol %, (b) being from 0.1 to 49.99 mol % and (c) being from 0.01 to 5 mol %, based on ((a)+(b)+(c)), and the electrical conductor layer (B) has a surface roughness of at most 10 μm on the side being in contact with the electrical insulator layer (A).
2. The laminate for a printed wiring board according to claim 1 , wherein the fluorocopolymer further contains repeating units (d) based on a non-fluorinated monomer excluding the monomer having an acid anhydride residue and a polymerizable unsaturated bond, and the molar ratio of ((a)+(b)+(c))/(d) is from 100/5 to 100/90.
3. The laminate for a printed wiring board according to claim 1 , wherein the monomer having an acid anhydride residue and a polymerizable unsaturated bond, is at least one member selected from the group consisting of itaconic anhydride, citraconic anhydride and 5-norbornene-2,3-dicarboxylic anhydride.
4. The laminate for a printed wiring board according to claim 1 , wherein the electrical conductor layer (B) is made of a metal foil of copper, silver, gold or aluminum, or a copper foil having gold plating applied thereon.
5. The laminate for a printed wiring board according to claim 1 , wherein the electrical conductor layer (B) has a thickness of at most 20 μm.
6. The laminate for a printed wiring board according to claim 1 , wherein the electrical conductor layer (B) is made of a copper foil.
7. The laminate for a printed wiring board according to claim 1 , wherein said surface roughness is from 0.1 to 5 μm.
8. The laminate for a printed wiring board according to claim 1 , wherein the electrical insulator layer (A) is formed of a fluorocopolymer comprising repeating units based on tetrafluoroethylene and chlorotrifluoroethylene.
9. The laminate for a printed wiring board according to claim 1 , wherein the electrical insulator layer (A) is formed from a fluorocopolymer comprising repeating units of itaconic anhydride, CH 2 ═CH(CF 2 ) 2 F, tetrafluoroethylene, and ethylene.
10. The laminate for a printed wiring board according to claim 1 , wherein the electrical insulator layer (A) is formed of a fluorocopolymer comprising repeating units based on tetrafluoroethylene, CF 2 ═CFOCF 2 CF 2 CF 3 and itaconic anhydride.
11. The laminate for a printed wiring board according to claim 1 , wherein the peel strength of the insulator layer (A) and the electrical conductor layer (B) has a peel strength according to IPCTM-6502.4.8 of from 15N/10 mm to 31N/10 mm.
12. The laminate for a printed wiring board according to claim 1 , wherein the electrical insulator layer (A) is formed of at least one fluorocopolymer selected from the group consisting of
a CF 2 ═CF 2 /CF 2 ═CFOCF 2 CF 2 CF 3 /(itaconic anhydride)copolymer,
a CF 2 ═CF 2 /CF 2 ═CFOCF 2 CF 2 CF 3 /(citraconic anhydride)copolymer,
a CF 2 ═CF 2 /hexafluoropropylene/(itaconic anhydride)copolymer,
a CF 2 ═CF 2 /hexafluoropropylene/(citraconic anhydride)copolymer,
a CF 2 ═CF 2 /(vinylidene fluoride)/(itaconic anhydride)copolymer,
a CF 2 ═CF 2 /(vinylidene fluoride)/(citraconic anhydride)copolymer,
a CF 2 ═CF 2 /CH 2 ═CH(CF 2 ) 4 F/(itaconic anhydride)/ethylene copolymer,
a CF 2 ═CF 2 /CH 2 ═CH(CF 2 ) 4 F/(citraconic anhydride)/ethylene copolymer,
a CF 2 ═CF 2 /CH 2 ═CH(CF 2 ) 2 F/(itaconic anhydride)/ethylene copolymer,
a CF 2 ═CF 2 /CH 2 ═CH(CF 2 ) 2 F/(citraconic anhydride)/ethylene copolymer,
a CClF═CF 2 /CH 2 ═CH(CF 2 ) 4 F/(itaconic anhydride)/ethylene copolymer,
a CClF═CF 2 /CH 2 ═CH(CF 2 ) 4 F/(citraconic anhydride)/ethylene copolymer,
a CClF═CF 2 /CH 2 ═CH(CF 2 ) 2 F/(itaconic anhydride)/ethylene copolymer and
a CClF═CF 2 /CH 2 ═CH(CF 2 ) 2 F/(citraconic anhydride)/ethylene copolymer.
13. The laminate for a printed wiring board according to claim 1 , wherein the fluorocopolymer of the electrical insulator layer (A) further comprises an inorganic filler.
14. The laminate for a printed wiring board according to claim 1 , wherein the electrical conductor layer (B) has a chromate film coating on the side opposite to the roughened surface.
15. The laminate for a printed wiring circuit board according to claim 1 , wherein the electrical insulated layer (A) is formed of a fluorocopolymer film covering a woven fibrous film.
16. The laminate for a printed wiring board according to claim 1 , wherein the electrical insulator layer (A) and the electrical conductor layer (B) are in direct and continuous contact.
17. The laminate for a printed wiring board according to claim 1 , wherein the electrical conductor layer (B) is a copper foil having gold plating.
18. A single-sided printed wiring board, comprising:
the laminate for a printed wiring board of claim 1 .
19. A double-sided printed wiring board, comprising:
the laminate for a printed wiring board of claim 1 , and
an electrical conductor layer (B) laminated to the surface of the insulator layer (A).
20. A multilayer circuit board, comprising:
a base plate layer, and
the laminate for a printed wiring board of claim 1 .
21. The multilayer circuit board of claim 20 , wherein the base plate is at least one electrical insulator layer selected from the group consisting of a woven inorganic fiber, a woven organic fiber, and an electrical insulator having a plurality of sheets of paper.