# US 11,027,458 B2 · Prepreg, metal-clad laminate, printed wiring board, and method for producing prepreg

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- Number: US 11,027,458 B2
- Document ID: US11027458B2
- Status: Granted
- Kind: B2
- Application number: 16/082,318
- Filed: 2017-02-15
- Published: 2019-03-21
- Granted: 2021-06-08
- Earliest claimed: 2016-03-23
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Hiroyuki Fujisawa; Kenichi Toshimitsu; Yoshihiko Nakamura
- Web page: https://patentgrep.com/patent/US11027458B2

## CPC

- B29B 15/125: {by dipping}
- B29B 15/122: {with a matrix in liquid form, e.g. as melt, solution or latex}
- B32B 5/024: {Woven fabric}
- B32B 5/26: another layer {next to it} also being fibrous or filamentary {(relative arrangement of fibres or filaments of different layers B32B5/12)}
- B32B 5/28: impregnated with or embedded in a plastic substance {(not used)}
- B32B 15/14: next to a fibrous or filamentary layer
- B32B 15/20: comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)}
- B32B 17/04: bonded with or embedded in a plastic substance
- C08J 5/244: {using glass fibres}
- C08J 5/249: {characterised by the additives used in the prepolymer mixture}
- H05K 1/03: Use of materials for the substrate
- H05K 1/036: {Multilayers with layers of different types}
- H05K 1/0366: {reinforced, e.g. by fibres, fabrics (H05K1/036 takes precedence)}
- H05K 1/0373: {containing additives, e.g. fillers (H05K1/036 takes precedence)}
- B32B 2250/02: 2 layers
- B32B 2250/03: 3 layers
- B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
- B32B 2255/02: on fibrous or filamentary layer
- B32B 2255/26: Polymeric coating
- B32B 2260/021: Fibrous or filamentary layer
- B32B 2260/046: Synthetic resin
- B32B 2262/101: Glass fibres
- B32B 2264/107: Ceramic
- B32B 2307/204: Di-electric
- B32B 2307/206: Insulating
- B32B 2307/732: Dimensional properties
- B32B 2457/08: PCBs, i.e. printed circuit boards
- C08J 2363/04: Epoxynovolacs
- C08J 2363/10: Epoxy resins modified by unsaturated compounds
- C08J 2463/04: Epoxynovolacs
- C08J 2463/10: Epoxy resins modified by unsaturated compounds
- H05K 2201/0195: Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure
- H05K 2201/0209: Inorganic, non-metallic particles
- H05K 2201/0269: Non-uniform distribution or concentration of particles
- H05K 2203/166: Alignment or registration; Control of registration
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

The prepreg includes a first resin layer and a second resin layer disposed on both surfaces of the first resin layer. The first resin layer is a half-cured product of a first resin composition that includes a glass cloth impregnated with the first resin composition and contains no hexagonal boron nitride. The second resin layer is a half-cured product of a second resin composition containing hexagonal boron nitride. The glass cloth has a warp and weft weave density of 54 pieces/25 mm or more. The hexagonal boron nitride has an average particle size ranging from 10 μm to 30 μm. The hexagonal boron nitride is contained in an amount ranging from 20 parts by mass to 40 parts by mass relative to 100 parts by mass of a residual component other than the hexagonal boron nitride in the second resin composition.

## Claims

### Claim 1

A prepreg comprising:
a first resin layer; and
a second resin layer disposed on each of opposite faces of the first resin layer,
wherein
the first resin layer is a half-cured product of a first thermosetting resin composition that includes a glass cloth impregnated with the first thermosetting resin composition and contains no hexagonal boron nitride,
the second resin layer is a half-cured product of a second thermosetting resin composition containing hexagonal boron nitride,
the glass cloth has a warp and weft weave density of 54 pieces/25 mm or more,
the hexagonal boron nitride has an average particle size ranging from 10 μm to 30 μm, and
the hexagonal boron nitride is contained in an amount ranging from 20 parts by mass to 40 parts by mass relative to 100 parts by mass of a residual component other than the hexagonal boron nitride in the second thermosetting resin composition.

### Claim 2 (depends on 1)

The prepreg according to claim 1, wherein the hexagonal boron nitride in the second resin layer is aligned in parallel with the glass cloth in the first resin layer.

### Claim 3 (depends on 1)

A metal-clad laminate comprising:
an insulating layer formed of a cured product of the prepreg according to claim 1; and
a metal layer disposed on one or both surfaces of the insulating layer.

### Claim 4 (depends on 1)

A printed wiring board comprising:
an insulating layer formed of a cured product of the prepreg according to claim 1; and
conductor wiring disposed on one or both surfaces of the insulating layer.

### Claim 5 (depends on 1)

A method for producing the prepreg according to claim 1, the method comprising steps of:
impregnating the glass cloth with a first varnish comprising the first thermosetting resin composition;
applying a second varnish comprising the second thermosetting resin composition to both surfaces of the glass cloth that has been impregnated with the first varnish; and
heating to half-cure the first thermosetting resin composition and the second thermosetting resin composition.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the first thermosetting resin composition is identical to a composition obtained by removing the hexagonal boron nitride from the second thermosetting resin composition.