Composition for optical waveguide, dry film for optical waveguide and optical waveguide using epoxies

Patent metadata

Field	Value
Publication number	US-10247883-B2
Application number	US-201615749525-A
Country	US
Kind code	B2
Filing date	Aug 23, 2016
Priority date	Sep 1, 2015
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A composition for an optical waveguide is cured into a sheet to give a cured product. A difference in light transmittance with respect to light having a wavelength of 450 nm is 15% or less between this cured product and this cured product after retention in atmosphere at 175° C. for 40 hours, the light transmittance being calculated in terms of the cured product at a thickness of 50 μm.

First claim

The invention claimed is:

1. A composition for an optical waveguide, which composition is curable into a sheet to give a cured product having a difference in light transmittance of 15% or less with respect to light having a wavelength of 450 nm between the cured product and the cured product after retention in atmosphere at 175° C. for 40 hours, the light transmittance being calculated in terms of the cured product at a thickness of 50 μm;
the composition comprising:
a liquid aliphatic epoxy compound;
a polyfunctional aromatic epoxy compound having three or more epoxy groups in a molecule;
a solid bisphenol A type epoxy compound having an epoxy equivalent ranging from 400 g/eq to 1500 g/eq, inclusive; and
a photocuring agent,

wherein a content of a liquid bisphenol A type epoxy compound, a phenol novolak type epoxy compound, a cresol novolak type epoxy compound, and a solid alicyclic epoxy compound having three or more epoxy groups in a molecule is 5% by mass or less, relative to a total amount of the epoxy compounds.

2. The composition for an optical waveguide according to claim 1 , wherein
a content of the liquid aliphatic epoxy compound ranges from 10% by mass to 30% by mass, inclusive, relative to the total amount of the epoxy compounds,
a content of the polyfunctional aromatic epoxy compound ranges from 10% by mass to 60% by mass, inclusive, relative to the total amount of the epoxy compounds,
a content of the solid bisphenol A type epoxy compound ranges from 10% by mass to 70% by mass, inclusive, relative to the total amount of the epoxy compounds, and
a content of the photocuring agent ranges from 0.3 parts by mass to 5 parts by mass, inclusive, relative to a total of 100 parts by mass of the epoxy compounds.

3. The composition for an optical waveguide according to claim 1 , the composition further comprising a solid aliphatic epoxy compound having two or more epoxy groups in a molecule.

4. The composition for an optical waveguide according to claim 3 , wherein the solid aliphatic epoxy compound is a solid hydrogenerated bisphenol A type epoxy compound.

5. The composition for an optical waveguide according to claim 3 , wherein a content of the solid aliphatic epoxy compound is 70% by mass or less, relative to the total amount of the epoxy compounds.

6. The composition for an optical waveguide according to claim 1 , the composition further comprising an antioxidant.

7. The composition for an optical waveguide according to claim 6 , wherein a content of the antioxidant is 5 parts by mass or less, relative to a total of 100 parts by mass of the epoxy compounds.

8. A dry film, comprising a layer made of a composition that is curable into a sheet to give a cured product having a difference in light transmittance of 15% or less with respect to light having a wavelength of 450 nm between the cured product and the cured product after retention in atmosphere at 175° C. for 40 hours, the light transmittance being calculated in terms of the cured product at a thickness of 50 μm;
the composition comprising:
a liquid aliphatic epoxy compound;
a polyfunctional aromatic epoxy compound having three or more epoxy groups in a molecule;
a solid bisphenol A type epoxy compound having an epoxy equivalent ranging from 400 g/eq to 1500 g/eq, inclusive; and
a photocuring agent,

wherein a content of a liquid bisphenol A type epoxy compound, a phenol novolak type epoxy compound, a cresol novolak type epoxy compound, and a solid alicyclic epoxy compound having three or more epoxy groups in a molecule is 5% by mass or less, relative to a total amount of the epoxy compounds.

9. An optical waveguide comprising a core portion and a clad layer covering the core portion,
at least one of the core portion and the clad layer being a cured product of a composition that is curable into a sheet to give a cured product having a difference in light transmittance of 15% or less with respect to light having a wavelength of 450 nm between the cured product and the cured product after retention in atmosphere at 175° C. for 40 hours, the light transmittance being calculated in terms of the cured product at a thickness of 50 μm;
the composition comprising:
a liquid aliphatic epoxy compound;
a polyfunctional aromatic epoxy compound having three or more epoxy groups in a molecule;
a solid bisphenol A type epoxy compound having an epoxy equivalent ranging from 400 g/eq to 1500 g/eq, inclusive; and
a photocuring agent,

wherein a content of a liquid bisphenol A type epoxy compound, a phenol novolak type epoxy compound, a cresol novolak type epoxy compound, and a solid alicyclic epoxy compound having three or more epoxy groups in a molecule is 5% by mass or less, relative to a total amount of the epoxy compounds.

10. The optical waveguide according to claim 9 , having an increase of waveguide loss of 1 dB/cm or less after a heat treatment at 150° C. for 1000 hours, with respect to waveguide loss before the heat treatment.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Kondou Naoyuki
• Hashimoto Shinji
• Nakashiba Toru
• Maeda Shingo
• Takagi Seiji

Classifications

• G02B6/1221

  made from organic materials · CPC title

• C08L63/08

  Epoxidised polymerised polyenes · CPC title

• C08L63/00

  Compositions of epoxy resins; Compositions of derivatives of epoxy resins · CPC title

• G02B1/10

  Optical coatings produced by application to, or surface treatment of, optical elements (G02B1/08 takes precedence) · CPC title

• G02B6/12

  of the integrated circuit kind (electric integrated circuits H10B, H10D84/00 - H10D89/00, H10F19/00, H10F39/00, H10H29/00, H10K19/00, H10K39/00, H10K59/00, H10N19/00, H10N39/00, H10N59/00, H10N69/00, H10N79/00, H10N89/00) · CPC title