Photosensitive epoxy resin composition, curable film for formation of optical waveguide core layer, and optical waveguide and optical/electrical transmission hybrid flexible printed wiring board produced by using the photosensitive epoxy resin composition or the curable film

Patent metadata

Field	Value
Publication number	US-10288770-B2
Application number	US-201414785933-A
Country	US
Kind code	B2
Filing date	Mar 11, 2014
Priority date	Apr 23, 2013
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

The present invention provides a photosensitive epoxy resin composition which contains: (A) a cresol novolak polyfunctional epoxy resin; (B) a liquid epoxy resin having a fluorene skeleton in its main chain; and (C) a photoacid generator; wherein the components (A) and (B) are present in a mixing weight ratio of (A)/(B)=40/60 to 60/40. Where the inventive photosensitive epoxy resin composition is used as an optical waveguide forming material, particularly as an optical waveguide core layer forming material for formation of a core layer, the optical waveguide core layer can be formed as having excellent reflow resistance and a lower loss through a coating process and a roll-to-roll process without altering the conventional production process.

First claim

What is claimed is:

1. A photosensitive epoxy resin composition comprising:
(A) a cresol novolak polyfunctional epoxy resin;
(B) a liquid epoxy resin having a fluorene skeleton in its main chain; and
(C) a photoacid generator;
wherein the components (A) and (B) are present in a mixing weight ratio of (A)/(B)=40/60 to 60/40.

2. The photosensitive epoxy resin composition according, to claim 1 , further comprising greater than 0 wt % and not greater than 5 wt % of a liquid bisphenol-A epoxy resin based on the weight of a resin component of the photosensitive epoxy resin composition.

3. The photosensitive epoxy resin composition according to claim 1 , wherein the photoacid generator (C) is present in a proportion of 0.1 to 10 parts by weight based on 100 parts by weight of a resin component of the photosensitive epoxy resin composition.

4. The photosensitive epoxy resin composition according to claim 1 , wherein the cresol novolak polyfunctional epoxy resin (A) is a cresol novolak polyfunctional epoxy resin represented by the following general formula (1):

wherein groups R, which may be the same or different, are each a C1 to C6 alkyl group, and n is a positive number.

5. The photosensitive epoxy resin composition according to claim 1 , wherein the liquid epoxy resin (B) having the fluorene skeleton in its main chain is a liquid epoxy resin represented by the following general formula (2):

wherein R 1 to R 4 , which may be the same or different, are each a hydrogen atom or a C1 to C6 alkyl group;
wherein R 5 and R 6 , which may be the same or different, are each a hydrogen atom or a methyl group; and
wherein each n is an integer of 0 to 10 which may be the same or different.

6. The photosensitive epoxy resin composition according to claim 1 , Which is a core layer forming material for an optical waveguide including a substrate, a cladding layer provided on the substrate, and a core layer provided in a predetermined pattern in the cladding layer for transmission of an optical signal.

7. A curable film for formation of an optical waveguide core layer, the curable film comprising the photosensitive epoxy resin composition according to claim 1 .

8. An optical waveguide comprising:
a substrate;
a cladding layer provided on the substrate; and
a core layer provided in a predetermined pattern in the cladding layer for transmission of an optical signal;
wherein the core layer is formed from the photosensitive epoxy resin composition according to claim 1 .

9. An optical waveguide comprising:
a substrate;
a cladding layer provided on the substrate; and
a core layer provided in a predetermined pattern in the cladding layer for transmission of an optical signal;
wherein the core layer is formed from the curable film according to claim 7 .

10. An optical/electrical transmission hybrid flexible printed wiring board comprising:
a flexible printed wiring board substrate; and
an optical waveguide provided on the flexible printed wiring board substrate;
wherein the optical waveguide is the optical waveguide according to claim 8 .

11. An optical/electrical transmission hybrid flexible printed wiring board comprising:
a flexible printed wiring board substrate; and
an optical waveguide provided on the flexible printed wiring board substrate;
wherein the optical waveguide is the optical waveguide according to claim 9 .

Assignees

• Nitto Denko Corp

Inventors

• Hirayama Tomoyuki
• Tanaka Naoyuki

Classifications

• H05K1/0393

  Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups) · CPC title

• H05K1/0326

  containing O · CPC title

• H05K1/0274

  Optical details, e.g. printed circuits comprising integral optical means (H05K1/0269 takes precedence; coupling light guides with opto-electronic components G02B6/42) · CPC title

• G02B6/138

  by using polymerisation · CPC title

• G02B1/046 Primary

  characterised by the core material · CPC title