JP2010091732A - Resin composition for forming core part and resin film for forming core part using the same, and optical waveguide using these - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for manufacturing an optical waveguide excellent in bending durability, twisting durability and sliding durability, and to provide an optical waveguide having the above characteristics. <P>SOLUTION: A resin composition for forming a core part of the optical waveguide contains (A) a base polymer, (B) a (meth)acrylate having an average addition molar number of 4 to 30 moles of ethylene oxide groups and/or propylene oxide groups, and (C) a photoradical polymerization initiator. A resin film for forming the core part is obtained using the resin composition for forming the core part. The optical waveguide has the core part formed by using the resin composition for forming the core part or the resin film for forming the core part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resin composition for forming a core part, a resin film for forming a core part, and an optical waveguide using these.

In high-speed and high-density signal transmission between electronic devices and between wiring boards, signal transmission interference and attenuation become barriers in conventional transmission using electric wiring, and the limits of high-speed and high-density are beginning to appear. In order to overcome this problem, a technique for optically connecting electronic elements and wiring boards, so-called optical interconnection, has been studied.
In order to transmit an optical signal over a short distance such as inside or between devices, a flexible film optical waveguide is desired. In particular, when an optical waveguide is wired inside a small portable device, the component film is often wired so that the surface of the component faces in order to save space. The polymer film optical waveguide can be bent with a small curvature radius. Is required.
In order to improve the flexibility of the flexible optical waveguide or the followability at the interface when the shape is restored, an optical waveguide using a low elastic modulus material has been developed. For example, in Patent Documents 1 and 2, the flexibility is improved by using an elastomer having a flexural modulus of 1000 MPa or less for the clad layer, and a resin containing a hydrogen bond group in the functional group of the precursor at a flexural modulus of 1000 MPa or less. The followability at the interface when bending or restoring the shape is improved by the film optical waveguide in which the clad layers are joined to each other, in particular, an elastomer having a bending elastic modulus of 200 MPa is used as the material of the upper clad layer and the lower clad layer. When a film optical waveguide in which clad layers are bonded to a functional group of a precursor via a resin containing a hydrogen bond group with a bending elastic modulus of 1000 MPa or less is used for a hinge portion of a mobile phone, it can be bent to a radius of curvature of 1 mm. , It is described that the interface does not peel even if it is repeatedly bent 200,000 times However, since the optical waveguide is manufactured using the stamper, there is a disadvantage that the degree of freedom in design is low and it is difficult to change the design. In addition, the bending durability has not been sufficiently evaluated, and when used in the hinge part of a mobile phone, in addition to bending durability, twisting durability and sliding durability are also required. It has not been done.

Japanese Patent No. 3870976 Japanese Patent No. 3906870

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a material for producing an optical waveguide having excellent bending durability, twisting durability, and sliding durability.

As a result of intensive studies, the present inventors have found that the bendability of the optical waveguide film is improved by using a specific resin composition for forming a clad layer. It has been found that by using a specific material as the resin composition for forming the core portion, the flexibility of the optical waveguide film is further improved, and an optical waveguide having excellent bending durability, twisting durability, and sliding durability can be obtained. The present invention has been reached.
That is, the present invention includes (A) a base polymer, (B) a (meth) acrylate having a total average number of added moles of ethylene oxide groups and / or propylene oxide groups of 4 to 30 moles, and (C) a radical photopolymerization initiator. Containing a resin composition for forming a core part of an optical waveguide, a resin film for forming a core part using the resin composition for forming a core part, a resin composition for forming a core part, or a core part forming resin composition An optical waveguide formed using a resin film is provided.

  According to the present invention, a core part-forming resin composition and a core part-forming resin film capable of producing an optical waveguide excellent in bending durability, twisting durability, and slide durability, and an optical light having the above characteristics A waveguide can be provided.

In the following, the present invention will be described in more detail.
As the resin composition for forming a core part of the present invention, (A) base polymer, (B) (meth) acrylate having an average addition mole number of ethylene oxide groups and / or propylene oxide groups of 4 to 30 moles in total, and ( C) It contains a photo radical polymerization initiator. Hereinafter, each component will be described more specifically.

  The (A) base polymer used in the present invention is for securing the strength when forming a cured product such as a film, and is not particularly limited as long as the object can be achieved. Examples thereof include resins, epoxy resins, (meth) acrylic resins, polycarbonates, polyarylates, polyether amides, polyether imides, polyether sulfones, and derivatives thereof. These base polymers may be used alone or in combination of two or more.

Of the (A) base polymers exemplified above, the main chain preferably has an aromatic skeleton, and particularly preferably a phenoxy resin, from the viewpoint of high heat resistance.
From the viewpoint of three-dimensional crosslinking and improving heat resistance, an epoxy resin, particularly a solid epoxy resin at room temperature (25 ° C.) is preferable.
Moreover, as (A) base polymer, when forming into a film using the resin composition containing said (A), (B) and (C) component, from a viewpoint of ensuring the transparency of this film, It is preferable that the compatibility with the component (B) described in detail is high. From this point, the phenoxy resin and (meth) acrylic resin are preferable. Here, (meth) acrylic resin means acrylic resin and methacrylic resin.

Specifically, the phenoxy resin includes at least one selected from the group consisting of bisphenol A, bisphenol A type epoxy compounds, bisphenol F, bisphenol F type epoxy compounds and derivatives thereof as a constituent unit of a copolymer component. Among these, from the viewpoint of having high heat resistance, a linear polymer of bisphenol A type epoxy resin is preferable. The linear polymer phenoxy resin is generally produced by a one-stage method in which bisphenol A and epichlorohydrin are polycondensed or by a two-stage method in which a bifunctional epoxy resin and bisphenol A are polyadded. It is what is done. Specific examples include “Phenotote YP-50, Phenotote YP-55, Phenotote YP-70” (all trade names), JP-A-4-120124, JP-A-4-122714, manufactured by Tohto Kasei Co., Ltd. And those described in JP-A-4-339852.
In addition, from the viewpoint of realizing high elongation or high strength of the resin composition for forming a core part, at least an aromatic epoxy compound such as a bisphenol A type epoxy compound or a bisphenol F type epoxy compound used as a copolymer component of a phenoxy resin. Preferable examples include an aliphatic epoxy compound or a phenoxy resin produced by replacing an epoxy compound with an ethylene oxide and / or propylene oxide adduct.

  In addition to the phenoxy resin, a high molecular weight product obtained by polyaddition reaction of various bifunctional epoxy resins and bisphenols, for example, brominated phenoxy resin (Japanese Patent Laid-Open No. 63-191826, Japanese Patent Publication No. 8-26119). No. 2), bisphenol A / bisphenol F copolymerization type phenoxy resin (Patent No. 2917884, No. 2799401), phosphorus-containing phenoxy resin (Japanese Patent Laid-Open No. 2001-310939), high heat resistance incorporating a fluorene skeleton Phenoxy resins (Japanese Patent Laid-Open Nos. 11-269264 and 11-302373) are also known as phenoxy resins.

  The following phenoxy resins represented by the bisphenol A / bisphenol F copolymer type phenoxy resin are suitably used as the component (A) in the present invention. That is, (a-1) at least one selected from bisphenol A, bisphenol A-type epoxy compounds and derivatives thereof, and (a-2) at least one selected from bisphenol F, bisphenol F-type epoxy compounds and derivatives thereof As a constituent unit of the copolymer component.

  By using a resin composition for forming a core part containing a resin having such a component (a-1) and (a-2) as a copolymerization component as the component (A), the cladding layer and the core layer It is possible to further improve the interlaminar adhesion and pattern formability (correspondence between fine lines or narrow lines) when forming the optical waveguide core pattern, and it is possible to form a fine pattern with a small line width or line.

Preferred examples of bisphenol A, bisphenol A type epoxy compounds or derivatives thereof include tetrabromobisphenol A, tetrabromobisphenol A type epoxy compounds, and hydrogenated bisphenol A type epoxy compounds.
Further, preferred examples of bisphenol F, or bisphenol F-type epoxy compounds or derivatives thereof include tetrabromobisphenol F, tetrabromobisphenol F-type epoxy compounds, and hydrogenated bisphenol F-type epoxy compounds.

  As described above, the (A) base polymer used in the present invention is particularly preferably a bisphenol A / bisphenol F copolymer phenoxy resin. For example, a trade name “Phenotote YP-” manufactured by Toto Kasei Co., Ltd. 70 ".

  Next, as an epoxy resin solid at room temperature (25 ° C.), for example, “Epototo YD-7020, Epototo YD-7019, Epototo YD-7007” (all trade names) manufactured by Tohto Kasei Co., Ltd., Japan Epoxy Resin Examples thereof include bisphenol A type epoxy resins such as “Epicoat 1010, Epicoat 1009, Epicoat 1008” (trade names) manufactured by Co., Ltd.

  (A) About the molecular weight of a base polymer, it is preferable that it is 20,000 or more by weight average molecular weight from a viewpoint of intensity | strength and flexibility, and it is more preferable that it is 50,000 or more. Although there is no restriction | limiting in particular about the upper limit of a weight average molecular weight, From a compatible viewpoint with (B) component and exposure developability, it is preferable that it is 1,000,000 or less, and it is 500,000 or less. More preferred. The weight average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene.

(A) It is preferable that the compounding quantity of a base polymer shall be 10-80 mass% with respect to the total amount of all the (meth) acrylate components in (A) component and the resin composition for core part formation. When the blending amount is 10% by mass or more, it becomes easy to form a resin composition containing the component (B) and the component (C), and when it is 80% by mass or less, an optical waveguide is formed. Furthermore, the pattern formability is improved and the photocuring reaction proceeds sufficiently.
From the above viewpoint, the blending amount of the (A) base polymer is more preferably 15 to 75% by mass with respect to the total amount of the (A) component and all (meth) acrylate components, and is 20 to 70% by mass. More preferably.
From the same viewpoint as described above, the blending amount of the (A) base polymer with respect to the total amount of the (A) component and the (B) component is preferably 10 to 80% by mass, more preferably 15 to 75% by mass, -70 mass% is more preferable.
In addition, in this invention, all (meth) acrylate components means the (meth) acrylate component contained in the resin composition for core part formation as a polymeric compound. Specifically, (B) component (meth) acrylate having an average addition mole number of ethylene oxide group and / or propylene oxide group of 4 to 30 mol in total, and (D) component hydroxyl group contained as necessary ( It means the total of (meth) acrylate and (meth) acrylate other than (B) component and (D) component contained if necessary.

In the present invention, (B) (meth) acrylate (hereinafter also simply referred to as “(B) (meth) acrylate”) having an average added mole number of ethylene oxide groups and / or propylene oxide groups of 4 to 30 moles is used. . When the total number of added moles is 4 moles or more, the tensile properties (tensile elongation at break, tensile elastic modulus, etc.) are improved as compared with the conventional core material, and the strength is increased or the elongation is increased. Elasticity can be realized, and the bending durability, twisting durability, and sliding durability of the optical waveguide can be improved. The upper limit of the total number of added moles is not particularly limited as long as it is 30 moles or less. However, from the viewpoint of suppressing heat resistance, moisture resistance, and interlayer adhesion with the cladding layer of the core portion in the optical waveguide, 20 It is preferably less than or equal to a mole. From the above viewpoint, the total of the average number of added moles of the ethylene oxide group and / or propylene oxide group is more preferably 4 to 15 mol, and further preferably 5 to 10 mol.
Here, (meth) acrylate refers to acrylate or methacrylate.

(B) As a (meth) acrylate having an average added mole number of ethylene oxide groups and / or propylene oxide groups of 4 to 30 moles, it is possible to ensure high refractive index as a core portion and to develop heat resistance. Aromatic (meth) acrylates are preferred.
Examples of the aromatic (meth) acrylate include phenoxyethyl (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, o-phenylphenoxyethyl (meth) acrylate, 1-naphthoxyethyl (meth) acrylate, 2 -Naphoxyethyl (meth) acrylate, N- (meth) acryloyloxyethylphthalimide, ethoxylated 2- (meth) acryloyloxyethyl-N-carbazole (both monofunctional), propoxylated thereof, and ethoxylated thereof Hydroquinone di (meth) acrylate, resorcinol (meth) acrylate, catechol di (meth) acrylate (both bifunctional) ethoxylates, their propoxylates, and their ethoxylated propoxylates Etc. is preferably Among them, from the same viewpoint as above, the aromatic represented by the following general formula (1) (meth) acrylate are more preferred.

(In the formula, R ¹ is a single bond, or

A represents an integer of 2 to 10. R ^{2 to} R ⁵ each independently represent a hydrogen atom or an organic group having 1 to 20 carbon atoms. R ⁶ and R ⁷ are each independently at least one divalent group selected from the group consisting of —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, and —CH ₂ CH (CH ₃ ) —. Indicates. b and c each independently represent an integer of 1 or more, and b + c represents an integer of 4 to 30. )

Here, in the general formula (1), the organic group represented by R ^{2 to} R ⁵ is not particularly limited as long as it is an organic group having 1 to 20 carbon atoms. For example, an alkyl group, a cycloalkyl group, and an aryl group And monovalent organic groups such as an aralkyl group, a carbonyl group, an ester group, and a carbamoyl group. These include a hydroxyl group, a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, a carbonyl group, and a formyl group. Group, ester group, carbamoyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, amino group, silyl group, silyloxy group and the like.

In general formula (1), when b is 2 or more, R ⁶ may be the same or different, and when c is 2 or more, R ⁷ may be the same or different. When they are different, R ⁶ O and R ⁷ O may be added in blocks or randomly.
b and c represent the average number of moles of the ethylene oxide group and / or propylene oxide group represented by R ⁶ O and R ⁷ O.
The sum (b + c) of b and c is 4-30. When b + c is 4 or more, high strength and low elasticity can be realized as the core material, and the bending durability, twisting durability, and sliding durability of the optical waveguide can be improved. The upper limit of b + c is not particularly limited as long as it is 30 or less, but it is preferably 20 or less from the viewpoint of heat resistance, moisture resistance, and suppression of lowering of interlayer adhesion with the cladding layer of the core portion in the optical waveguide. . From the above viewpoint, b + c is more preferably 4 to 15, and further preferably 5 to 10.

  As the aromatic (meth) acrylate represented by the general formula (1), bisphenol A di (meth) acrylate and bisphenol are used from the viewpoint of ensuring high refractive index as a core part and expressing transparency and heat resistance. F di (meth) acrylate, bisphenol AF di (meth) acrylate, ethoxylated aromatic (meth) acrylates such as fluorene type di (meth) acrylate, propoxylated compounds thereof, and ethoxylated propoxylated compounds thereof Are preferable.

It is preferable that the compounding quantity of (B) (meth) acrylate used for this invention is 10-90 mass% with respect to the total amount of (A) component and the said all (meth) acrylate component. When the blending amount is 10% by mass or more, the pattern formability is improved and the photocuring reaction proceeds sufficiently when the optical waveguide is formed. If it is 90 mass% or less, it will become easy to film-form the resin composition containing (A) component and (C) component. From the above viewpoint, the blending amount of the component (B) is more preferably 25 to 85% by mass, and 30 to 80% by mass with respect to the total amount of the (A) component and the total (meth) acrylate component. More preferably it is.
Further, from the same viewpoint as described above, the blending amount of (B) (meth) acrylate with respect to the total amount of component (A) and component (B) is preferably 20 to 90% by mass, and more preferably 25 to 85% by mass. 30 to 80% by mass is more preferable.
In addition, in this invention, unless the effect of this invention is inhibited, (meth) acrylate whose sum total of the average addition mole number of an ethylene oxide group and / or a propylene oxide group is 1 or more and less than 4 mol can also be contained.

  In the resin composition for forming a core part of the present invention, (D) (meth) acrylate having a hydroxyl group can be used as necessary. By using the component (B) and the component (D) in combination, it is possible to achieve low elasticity as the core material while ensuring interlayer adhesion with the cladding layer in the core portion of the optical waveguide. The (D) hydroxyl group-containing (meth) acrylate in the present invention does not include (meth) acrylate having an average of 4 to 30 moles of ethylene oxide group and / or propylene oxide group added.

(D) There is no restriction | limiting in particular as (meth) acrylate which has a hydroxyl group, For example, any of a monofunctional thing, a bifunctional thing, and a polyfunctional thing more than trifunctional can be used. Among these, monofunctional (meth) acrylates are preferable from the viewpoint of increasing strength or increasing elongation and reducing elasticity.
Monofunctional (meth) acrylates having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth). Aliphatic (meth) acrylates such as acrylate; 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (1- And aromatic (meth) acrylates such as naphthoxy) propyl (meth) acrylate and 2-hydroxy-3- (2-naphthoxy) propyl (meth) acrylate.
Examples of the bifunctional (meth) acrylate having a hydroxyl group include resorcinol type epoxy (meth) acrylate, bisphenol A type epoxy (meth) acrylate, bisphenol F type epoxy (meth) acrylate, bisphenol AF type epoxy (meth) acrylate, and fluorene type epoxy. Aromatic epoxy (meth) acrylates such as (meth) acrylates are listed.
Examples of the trifunctional or higher polyfunctional (meth) acrylate having a hydroxyl group include aromatic epoxy (meth) acrylates such as phenol novolac type epoxy (meth) acrylate and cresol novolac type epoxy (meth) acrylate.
Among these, aromatic (meth) acrylate is preferable from the viewpoint of ensuring high refractive index properties as a core portion and expressing heat resistance, and the monofunctional aromatic (meth) acrylate and bifunctional exemplified above are preferred. The aromatic epoxy (meth) acrylate is more preferably monofunctional aromatic (meth) acrylate.

  The blending amount of the (D) hydroxyl group-containing (meth) acrylate used in the present invention is preferably 10 to 80% by mass with respect to the total amount of the (A) component and all (meth) acrylate components. When the blending amount is 10% by mass or more, the pattern formability is improved and the photocuring reaction proceeds sufficiently when the optical waveguide is formed. If it is 80 mass% or less, it will become easy to film-form the resin composition containing (A) component, (B) component, (C) component, and (D) component. From the above viewpoint, the blending amount of the component (D) is more preferably 15 to 70% by mass with respect to the total amount of the (A) component and all (meth) acrylate components, and is 20 to 60% by mass. More preferably. Further, from the same viewpoint as described above, the blending amount of the component (D) with respect to the total amount of the components (A), (B), and (D) is preferably 10 to 80% by weight, and preferably 15 to 70% by weight. Is more preferable, and 20-60 mass% is further more preferable.

  In the present invention, a (meth) acrylate other than the component (B) and the component (D) may be contained as long as the effects of the present invention are not impaired. For example, bisphenol A di (meth) acrylate, bisphenol F di (meta) ) Acrylate, bisphenol AF di (meth) acrylate, fluorene type di (meth) acrylate, hydroquinone di (meth) acrylate, resorcinol (meth) acrylate, catechol di (meth) acrylate, etc. bifunctional aromatic (meth) acrylate; phenyl (Meth) acrylate, benzyl (meth) acrylate, o-biphenyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, phenoxyethyl (meth) acrylate, p-cumylphenoxyethyl (meth) Acry , O-phenylphenoxyethyl (meth) acrylate, 1-naphthoxyethyl (meth) acrylate, 2-naphthoxyethyl (meth) acrylate, N- (meth) acryloyloxyethylphthalimide, 2- (meth) acryloyloxyethyl-N- And monofunctional aromatic (meth) acrylates such as carbazole.

There is no restriction | limiting in particular as (C) radical photopolymerization initiator in this invention, For example, benzoinketals, such as 2, 2- dimethoxy- 1, 2- diphenyl ethane- 1-one; 1-hydroxy cyclohexyl phenyl ketone, 2- Hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1 Α-hydroxy ketones such as {4 [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methylpropan-1-one; methyl phenylglyoxylate, ethyl phenylglyoxylate, oxyphenylacetic acid 2 -(2-hydroxyethoxy) ethyl, oxyphenylacetic acid 2- (2-oxo-2-phen Glyoxyesters such as ruacetoxyethoxy) ethyl; 2-benzyl-2-dimethylamino-1- (4-morpholin-4-ylphenyl) -butan-1-one, 2-dimethylamino-2- (4- Methylbenzyl) -1- (4-morpholin-4-ylphenyl) -butan-1-one, 1,2-methyl-1- [4- (methylthio) phenyl]-(4-morpholine) -2- Α-amino ketones such as ylpropan-1-one; 1,2-octanedione, 1- [4- (phenylthio), 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- ( Oxime esters such as 2-methylbenzoyl) -9H-carbazol-3-yl], 1- (O-acetyloxime); bis (2,4,6-trimethylbenzoyl) phenylphosphine Oxides, phosphine oxides such as bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 2- (o-chlorophenyl) -4,5 -Diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- 2,4,5-triarylimidazole dimers such as (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer; Benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone, N, N′-te Benzophenone compounds such as raethyl-4,4′-diaminobenzophenone and 4-methoxy-4′-dimethylaminobenzophenone; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1 Quinone compounds such as 1,4-naphthoquinone and 2,3-dimethylanthraquinone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether; benzoin and methylben Benzoin compounds such as in and ethyl benzoin; benzyl compounds such as benzyl dimethyl ketal; acridine compounds such as 9-phenylacridine and 1,7-bis (9,9′-acridinylheptane): N-phenylglycine, coumarin and the like Is mentioned.
In the 2,4,5-triarylimidazole dimer, the substituents of the aryl groups at the two triarylimidazole sites may give the same and symmetric compounds, but give differently asymmetric compounds. May be.
Among these, from the viewpoint of curability and transparency, the α-hydroxyketone; the glyoxyester; the oxime ester; and the phosphine oxide are preferable.
The above radical photopolymerization initiators can be used alone or in combination of two or more. Furthermore, it can also be used in combination with an appropriate sensitizer.

  (C) It is preferable that the compounding quantity of the radical photopolymerization initiator of a component is 0.01-10 mass parts with respect to 100 mass parts of total amounts of (A) component and the said all (meth) acrylate component. If it is 0.01 mass part or more, sufficient sclerosis | hardenability will be obtained, and if it is 10 mass parts or less, sufficient light transmittance will be obtained. From the above viewpoint, the compounding amount of the radical photopolymerization initiator of the component (C) is 0.05 to 7 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the total (meth) acrylate component. Is more preferable, and 0.1 to 5 parts by mass is particularly preferable.

  In addition, in the resin composition for forming a core part of the present invention, an antioxidant, a yellowing inhibitor, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, a filler, and the like as necessary. These so-called additives may be added at a rate that does not adversely affect the effects of the present invention.

The resin composition for forming a core part of the present invention is used for a core part of an optical waveguide and may be diluted with a suitable organic solvent and used as a resin varnish for forming a core part. The solvent for varnishing is not particularly limited as long as it can dissolve the core composition resin composition of the present invention. For example, aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, p-cymene, etc. Chain ethers such as diethyl ether, tert-butyl methyl ether, cyclopentyl methyl ether and dibutyl ether; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol and propylene glycol Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone; methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, γ-butyrolacto Esters such as; carbonates such as ethylene carbonate and propylene carbonate; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Polyhydric alcohol alkyl ethers such as propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether; Polyhydric alcohol alkyl ether acetates such as coal monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate; Examples thereof include amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone.
These organic solvents can be used alone or in combination of two or more. Moreover, it is preferable that the solid content density | concentration in a resin varnish is 10-80 mass% normally.

  When the resin composition for forming a core part of the present invention is prepared, it is preferably mixed by stirring. Although there is no restriction | limiting in particular in the stirring method, From the viewpoint of stirring efficiency, stirring using a propeller is preferable. Although there is no restriction | limiting in particular in the rotational speed of the propeller at the time of stirring, It is preferable that it is 10-1,000 rpm. If it is 10 rpm or more, each component will be sufficiently mixed, and if it is 1,000 rpm or less, entrainment of bubbles due to rotation of the propeller will be reduced. From the above viewpoint, it is more preferable that it is 50-800 rpm, and it is especially preferable that it is 100-500 rpm. Although there is no restriction | limiting in particular in stirring time, It is preferable that it is 1 to 24 hours. If it is 1 hour or more, each component will be fully mixed, and if it is 24 hours or less, the varnish preparation time can be shortened and productivity can be improved.

  The prepared resin composition for forming a core part or resin varnish is preferably degassed under reduced pressure. Although there is no restriction | limiting in particular in the defoaming method, For example, the method of using a vacuum pump, a bell jar, and the defoaming apparatus with a vacuum apparatus is mentioned. Although there is no restriction | limiting in particular in the pressure at the time of pressure reduction, The pressure in which the low boiling point component contained in a resin composition does not boil is preferable. Although there is no restriction | limiting in particular in vacuum degassing time, It is preferable that it is 3 to 60 minutes. If it is 3 minutes or longer, bubbles dissolved in the resin composition can be removed, and if it is 60 minutes or less, the organic solvent contained in the resin composition does not volatilize and the defoaming time is shortened. And productivity can be improved.

Hereinafter, the cured film formed by curing the resin composition for forming a core part of the present invention will be described.
The tensile elongation at break in a tensile test at 25 ° C. of a cured film obtained by curing the resin composition for forming a core of the present invention is preferably 2.5% or more, more preferably 2.5 to 200%. ˜100% is more preferable. When the tensile elongation at break is 2.5% or more, the strength of the core portion can be increased, which is preferable. If the tensile elongation at break is 200% or less, it does not break even when stress is applied to the core part by a bending test, a bending test, a torsion test, or a slide test, which is preferable. The tensile elongation at break means the elongation at the time when the film is broken in the film tensile test.

The tensile elastic modulus at 25 ° C. of the cured film obtained by curing the core portion forming resin composition of the present invention is preferably 30 to 5000 MPa, more preferably 50 to 4000 MPa, and further preferably 100 to 3000 MPa.
If the elastic modulus of the cured film is 5000 MPa or less, if the film has a sufficient elongation as described above, it can be bent with a small radius of curvature when the film is bent in the thickness direction. On the other hand, when the pressure is 30 MPa or more, the deformation of the core can be reduced even when stress is applied to the core when the bending test, the twisting test, and the sliding test are performed, and the deterioration of the transmission characteristics of the film optical waveguide is suppressed. Can be preferred.
In the resin composition for forming a core part of the present invention, from the viewpoint of securing the strength of the optical waveguide and imparting bending durability, twisting durability, and sliding durability, both the tensile elastic modulus and the tensile elastic modulus are Are preferably in the above-mentioned ranges.

  It is preferable that the refractive index in wavelength 830nm in the temperature of 25 degreeC of the cured film formed by superposing | polymerizing and hardening | curing the resin composition for core part formation of this invention is 1.400-1.700. If the refractive index is 1.400 to 1.700, the refractive index is not significantly different from that of a normal optical resin, so that versatility as an optical material is not impaired. From the above viewpoint, the refractive index of the cured film is more preferably 1.425 to 1.675, and particularly preferably 1.450 to 1.650.

Hereinafter, the resin film for forming a core part of the present invention will be described.
The resin film for forming a core part of the present invention uses the resin composition for forming a core part, and contains the components (A), (B) and (C), and further a component (D) used as necessary. It can manufacture easily by apply | coating the resin composition for core part formation to a suitable support film. Moreover, when the said resin composition for core part formation is diluted with the said organic solvent, it can manufacture by apply | coating a resin composition to a support film and removing an organic solvent.

The support film used in the production process of the core portion forming resin film is not particularly limited as long as the actinic ray for exposure used for forming the core pattern is transmitted. For example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc. Polyesters of polyethylene, polyolefins such as polyethylene, polypropylene; polycarbonate, polyamide, polyimide, polyamideimide, polyetherimide, polyethersulfide, polyethersulfone, polyetherketone, polyphenyleneether, polyphenylenesulfide, polyarylate, polysulfone, liquid crystal polymer, etc. Can be mentioned.
Among these, the polyester and the polyolefin are preferable from the viewpoints of the transmittance of exposure actinic rays, flexibility, and toughness. Furthermore, it is more preferable to use a highly transparent support film from the viewpoint of improving the transmittance of exposure actinic rays and reducing the roughness of the side wall of the core pattern. Examples of such highly transparent support films include Cosmo Shine A1517 and Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.
In addition, you may use the film in which the mold release process was given with the silicone type compound, the fluorine-containing compound, etc. from a viewpoint of peelability improvement with a resin layer as needed.

  The thickness of the support film of the core portion forming resin film is preferably 5 to 50 μm. If it is 5 μm or more, the strength as a support is sufficient, and if it is 50 μm or less, the gap between the photomask and the core portion forming resin layer is not increased during the formation of the core pattern, and the pattern resolution is good. From the above viewpoint, the thickness of the support film is more preferably 10 to 40 μm, and particularly preferably 15 to 30 μm.

  The core part-forming resin film produced by applying the core part-forming resin composition on the support film is composed of a support film, a resin layer, and a protective film, with a protective film attached to the resin layer as necessary. A three-layer structure may be used.

  The protective film is not particularly limited, but from the viewpoint of flexibility and toughness, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene are preferably used. In addition, you may use the film in which the mold release process was given with the silicone type compound, the fluorine-containing compound, etc. from a viewpoint of peelability improvement with a resin layer as needed.

  The thickness of the protective film may be appropriately changed depending on the intended flexibility, but is preferably 10 to 250 μm. When it is 10 μm or more, the film strength is sufficient, and when it is 250 μm or less, sufficient flexibility is obtained. From the above viewpoint, the thickness of the protective film is more preferably 15 to 200 μm, and particularly preferably 20 to 150 μm.

  Although it does not specifically limit about the thickness of the resin layer of the resin film for core part formation of this invention, It is the thickness after drying, and it is usually preferable that it is 5-500 micrometers. If the thickness is 5 μm or more, the strength of the resin film or the cured product of the resin film is sufficient because the thickness is sufficient, and if it is 500 μm or less, the drying can be performed sufficiently so that the amount of residual solvent in the resin film does not increase. When the cured resin film is heated, it does not foam.

  The core part-forming resin film thus obtained can be easily stored by, for example, winding it into a roll. Moreover, a roll-shaped film can be cut out into a suitable size and stored in a sheet shape.

Hereinafter, application examples when the resin composition for forming a core part or the resin film for forming a core part is used for the optical waveguide of the present invention will be described.
The optical waveguide of the present invention is designed such that the core portion has a higher refractive index than the cladding layer, and the cladding layer is formed of a resin composition having a refractive index lower than that of the core portion.
Although there is no restriction | limiting in particular as a resin composition for clad layer formation, From a viewpoint of improving the bending durability of an optical waveguide, twisting durability, and slide durability, it is preferable to use a low elastic modulus material. Bending durability, twisting durability, and sliding durability are further improved by using a low elastic modulus clad layer forming resin composition in an optical waveguide using the core portion forming resin composition of the present invention. It is considered possible. From this viewpoint, a resin composition for forming a cladding layer containing (A ′) an elastomer, (B ′) (meth) acrylate, and (C ′) a radical polymerization initiator is used as at least one of the upper cladding layer and the lower cladding layer. It is preferable to use it for a layer.

(A ') There is no restriction | limiting in particular as an elastomer, Urethane rubbers, such as diene type synthetic rubbers, such as an acrylic rubber, acrylonitrile-butadiene rubber, and a butadiene rubber, polyether urethane, polyester urethane, etc. can be used. Of these, acrylic rubber is preferred from the viewpoints of heat resistance and solvent resistance.
Here, the acrylic rubber refers to a polymer containing structural units derived from monomers such as acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, and derivatives thereof. The acrylic rubber may be a homopolymer of the above monomer, or may be a copolymer obtained by polymerizing two or more of these monomers.
Examples of the acrylic rubber include rubbers mainly composed of an acrylate ester and mainly composed of a copolymer such as butyl acrylate and acrylonitrile, a copolymer such as ethyl acrylate and acrylonitrile, or the like.
Examples of the copolymer monomer include butyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, acrylonitrile and the like.
Furthermore, the copolymer containing said monomer and monomers other than the above may be used in the range which does not inhibit the effect of this invention. Further, it may be a mixture of a plurality of acrylic rubbers.

As the acrylic rubber used as the component (A ′), those containing a reactive functional group such as an epoxy group, an acryloyl group, a methacryloyl group, a carboxyl group, a hydroxyl group, and an episulfide group are preferable. preferable.
When an epoxy group is selected as the reactive functional group, it is preferable to use an ethylenically unsaturated epoxide as the copolymer monomer component.
The ethylenically unsaturated epoxide is not particularly limited, and examples thereof include glycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 3,4-epoxycyclohexyl. Preferred examples include ethyl (meth) acrylate and the like.
Such an epoxy group-containing (meth) acrylic polymer having a weight average molecular weight of 100,000 or more can be produced by appropriately selecting a monomer from the above monomers, or a commercially available product (for example, HTR- manufactured by Nagase ChemteX Corporation). 860P-3, HTR-860P-5, etc.).
When the epoxy group-containing acrylic rubber is used as the component (A ′), the amount of the ethylenically unsaturated epoxide used as a raw material is preferably 0.5 to 6.0% by mass of the copolymer. When the amount of the epoxy group-containing repeating unit is within this range, the epoxy group gradually crosslinks, so that an optical waveguide having an appropriate elastic modulus that can withstand a bending test, a twisting test, a sliding test, and the like can be obtained.

  (A ′) The weight average molecular weight of the elastomer is preferably 100,000 to 3,000,000, more preferably 300,000 to 3,000,000, and particularly preferably 500,000 to 2,000,000. If the weight average molecular weight is 100,000 or more, the strength and flexibility in sheet form and film form are sufficient and tackiness does not increase. On the other hand, if it is 3 million or less, the compatibility with (B ′) (meth) acrylate described later is good, the flow property is sufficient, and the core embedding property does not deteriorate.

  The blending amount of the (A ′) elastomer is preferably 10 to 80% by mass with respect to the total amount of the (A ′) component and the (B ′) component. When the content is 10% by mass or more, the low elasticity of the (A ′) elastomer functions, and the bending durability, twisting durability, and sliding durability of the optical waveguide are improved without the film becoming brittle. When it is 80% by mass or less, the polymerization reaction of the component (B ′) is likely to occur, so that the peelability from the supporting substrate is improved. From the above viewpoint, the blending amount of the component (A ′) is more preferably 15 to 70% by mass with respect to the total amount of the component (A ′) and the component (B ′), and is preferably 20 to 60% by mass. It is particularly preferred.

(B ′) (Meth) acrylate preferably contains urethane (meth) acrylate from the viewpoint of imparting flexibility and toughness.
As the urethane (meth) acrylate, for example, a known urethane (meth) acrylate obtained by a reaction between a hydroxyl group-containing (meth) acrylate and a polyisocyanate or a reaction between a hydroxyl group-containing (meth) acrylate, a polyisocyanate and a polyol is used. Can do. (A ′) From the viewpoint of compatibility with the elastomer, urethane (meth) acrylate obtained by reaction of a hydroxyl group-containing (meth) acrylate and a polyisocyanate is preferable.

  As urethane (meth) acrylate obtained by reaction of hydroxyl group-containing (meth) acrylate and polyisocyanate, for example, hydroxyethyl (meth) acrylate and 2,5- or 2,6-bis (isocyanatomethyl) -bicyclo [2. 2.1] Reaction product of heptane, reaction product of hydroxyethyl (meth) acrylate and 2,4-tolylene diisocyanate, reaction product of hydroxyethyl (meth) acrylate and isophorone diisocyanate, hydroxypropyl (meth) acrylate Reaction product of 2,4-tolylene diisocyanate, reaction product of hydroxypropyl (meth) acrylate and isophorone diisocyanate, reaction product of phenylglycidyl ether (meth) acrylate and hexamethylene diisocyanate, Reaction product of glycidyl ether and toluene diisocyanate, reaction product of pentaerythritol tri (meth) acrylate and hexamethylene diisocyanate, reaction product of pentaerythritol tri (meth) acrylate and toluene diisocyanate, pentaerythritol tri (meth) acrylate and isophorone Examples thereof include a reaction product of disicocyanate, a reaction product of dipentaerythritol penta (meth) acrylate and hexamethylene diisocyanate, and the like.

Examples of the polyol used when producing a urethane (meth) acrylate obtained by the reaction of a hydroxyl group-containing (meth) acrylate, a polyisocyanate, and a polyol include polyether diol, polyester diol, polycarbonate diol, and polycaprolactone diol. .
Polyether diols include aliphatic, alicyclic, and aromatic types.
These polyols can be used alone or in combination of two or more.
As the polyol, a dihydric or higher polyol synthesized by a reaction between a diol and a polyisocyanate can also be used.
The polymerization mode of each structural unit in these polyols is not particularly limited, and may be any of random polymerization, block polymerization, and graft polymerization.
Examples of the aliphatic polyether diol include ring-opening copolymerization of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, and two or more ion-polymerizable cyclic compounds. Polyether diol obtained by the above.

Examples of the ion polymerizable cyclic compound include ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, and tetraoxane. , Cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monooxide, isoprene monooxide, vinyl oxetane, vinyl tetrahydrofuran, vinyl cyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, glycidyl benzoate And cyclic ethers.
Specific examples of polyether diols obtained by ring-opening copolymerization of two or more of the above ion-polymerizable cyclic compounds include, for example, tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and the like. Binary copolymers obtained from combinations of ethylene oxide, propylene oxide and ethylene oxide, butene-1-oxide and ethylene oxide; terpolymers obtained from combinations of tetrahydrofuran, butene-1-oxide and ethylene oxide .

Further, a polyether diol obtained by ring-opening copolymerization of the ion polymerizable cyclic compound and a cyclic imine such as ethyleneimine; a cyclic lactone acid such as β-propiolactone or glycolic acid lactide; or a dimethylcyclopolysiloxane. Can also be used.
Examples of the alicyclic polyether diol include hydrogenated bisphenol A alkylene oxide addition diol, hydrogenated bisphenol F alkylene oxide addition diol, 1,4-cyclohexanediol alkylene oxide addition diol, and the like.

Further, as (B ′) (meth) acrylate, (meth) acrylate having no urethane bond in the molecule can be used. There is no restriction | limiting in particular as such (meth) acrylate, For example, any of a monofunctional thing, a bifunctional thing, or a polyfunctional thing more than trifunctional can be used.
There is no restriction | limiting in particular as monofunctional (meth) acrylate, For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) Acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, butoxyethyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate , Octyl heptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate Tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3- Aliphatic (meth) acrylates such as chloro-2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate; cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, dicyclopentanyl Alicyclic (meth) acrylates such as (meth) acrylate, dicyclopentenyl (meth) acrylate, isobornyl (meth) acrylate; phenyl (meth) acrylate, Nylphenyl (meth) acrylate, p-cumylphenyl (meth) acrylate, o-biphenyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxy-3- Phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (1-naphthoxy) propyl (meth) acrylate, 2-hydroxy-3- (2 -Aromatic (meth) acrylates such as naphthoxy) propyl (meth) acrylate; 2-tetrahydrofurfuryl (meth) acrylate, N- (meth) acryloyloxyethyl hexahydrophthalimide, 2- (meth) acryloyloxyethyl-N- Mosquito Examples thereof include heterocyclic (meth) acrylates such as rubazole; ethoxylated products thereof; propoxylated products thereof; ethoxylated propoxylated products thereof; modified caprolactones thereof and the like.
Among these, from the viewpoint of transparency and compatibility with (A ′) elastomer, the above aliphatic (meth) acrylate; the above alicyclic (meth) acrylate; the above heterocyclic (meth) acrylate; These propoxylated compounds; these ethoxylated propoxylated compounds; and these caprolactone-modified products are preferable.

There is no restriction | limiting in particular as bifunctional (meth) acrylate, For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 2-methyl-1,3-propanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate , Neopentyl glycol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2-butyl-2-ethyl-1, 3-propanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, glycerin di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate Aliphatic (meth) acrylates such as: cyclohexanedimethanol (meth) acrylate, ethoxylated cyclohexanedimethanol (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, hydrogenated bisphenol A di (meth) acrylate, hydrogenated bisphenol F Alicyclic (meth) acrylates such as meth) acrylate; aromatics such as bisphenol A di (meth) acrylate, bisphenol F di (meth) acrylate, bisphenol AF di (meth) acrylate, and fluorene type di (meth) acrylate Heterocyclic (meth) acrylates such as isocyanuric acid di (meth) acrylate; ethoxylated products thereof; propoxylated products thereof; ethoxylated propoxylated products thereof; modified caprolactone products thereof; neopentyl glycol type Aliphatic epoxy (meth) acrylates such as epoxy (meth) acrylate; cyclohexanedimethanol type epoxy (meth) acrylate, hydrogenated bisphenol A type epoxy (meth) acrylate, hydrogenated bisphenol F type epoxy (meth) Alicyclic epoxy (meth) acrylates such as acrylate; resorcinol type epoxy (meth) acrylate, bisphenol A type epoxy (meth) acrylate, bisphenol F type epoxy (meth) acrylate, bisphenol AF type epoxy (meth) acrylate, fluorene type epoxy Aromatic epoxy (meth) acrylates such as (meth) acrylates may be mentioned.
Among these, from the viewpoint of transparency and compatibility with (A ′) elastomer, the above aliphatic (meth) acrylate; the above alicyclic (meth) acrylate; the above heterocyclic (meth) acrylate; These propoxy compounds; these ethoxylated propoxy compounds; these caprolactone-modified products; the above aliphatic epoxy (meth) acrylates; and the alicyclic epoxy (meth) acrylates.

The trifunctional or higher polyfunctional (meth) acrylate is not particularly limited. For example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra ( Aliphatic (meth) acrylates such as (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate; heterocyclic (meth) acrylates such as isocyanuric acid tri (meth) acrylate; these ethoxys These propoxylated products; These ethoxylated propoxylated products; These caprolactone modified products; Phenol novolac epoxy (meth) acrylate, Cresol novolac epoxy ( Aromatic epoxy (meth) acrylates such as data) acrylate.
Among these, from the viewpoint of transparency and compatibility with (A ′) elastomer, the above aliphatic (meth) acrylate; the above heterocyclic (meth) acrylate; the ethoxylated product thereof; the propoxylated product thereof; An ethoxylated propoxy compound of the above; preferably a caprolactone modified product thereof.

  The blending amount of (B ′) (meth) acrylate is preferably 20 to 90% by mass with respect to the total amount of component (A ′) and component (B ′). When the content is 20% by mass or more, the polymerization reaction of the component (B ′) tends to occur, so that the peelability from the supporting substrate tends to be improved. If it is 90% by mass or less, the low elasticity of the (A ′) elastomer functions and the film does not become brittle, and the bending durability, twisting durability, and sliding durability of the optical waveguide are improved, which is preferable. From the above viewpoint, the blending amount of the component (B ′) is more preferably 30 to 85% by mass, and 40 to 80% by mass with respect to the total amount of the component (A ′) and the component (B ′). It is particularly preferred.

(C ') There is no restriction | limiting in particular as a radical polymerization initiator, A well-known photoradical polymerization initiator and a thermal radical polymerization initiator can be used. Examples of the photo radical polymerization initiator include the photo radical polymerization initiators exemplified above. Examples of the thermal radical polymerization initiator include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butyl peroxide). Oxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis ( peroxyketals such as t-hexylperoxy) -3,3,5-trimethylcyclohexane; hydroperoxides such as p-menthane hydroperoxide; α, α′-bis (t-butylperoxy) diisopropylbenzene, dioctyl Milperoxide, t-butylcumyl peroxide Dialkyl peroxides such as di-t-butyl peroxide; diacyl peroxides such as octanoyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide; bis (4-t-butylcyclohexyl) peroxydicarbonate, di- Peroxycarbonates such as 2-ethoxyethyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-3-methoxybutyl peroxycarbonate; t-butyl peroxypivalate, t-hexyl peroxypivalate 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t-hexylperoxy- 2-ethylhexa Noate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, 2,5-dimethyl-2 Peroxyesters such as 2,5-bis (benzoylperoxy) hexane and t-butylperoxyacetate; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) 2,2′-azobis (4-methoxy-2′-di And azo compounds such as methyl valeronitrile).
The above heat and photo radical polymerization initiators can be used alone or in combination of two or more. Furthermore, it can also be used in combination with an appropriate sensitizer.

  The compounding amount of the photoradical polymerization initiator of the component (C ′) is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the components (A ′) and (B ′). If it is 0.01 mass part or more, hardening will be enough, and if it is 10 mass parts or less, sufficient light transmittance will be obtained. From the above viewpoint, the compounding amount of the component (C ′) is more preferably 0.05 to 7 parts by mass with respect to 100 parts by mass of the total amount of the component (A ′) and the component (B ′). It is particularly preferably 1 to 5 parts by mass.

The tensile elastic modulus at 25 ° C. of a cured film obtained by curing the resin composition for forming a clad layer is preferably 1 to 2000 MPa, more preferably 10 to 1500 MPa, and further preferably 20 to 1000 MPa.
Further, the tensile elongation at break in a tensile test at 25 ° C. of a cured film obtained by curing the resin composition for forming a clad layer is preferably 10 to 600%, more preferably 15 to 400%, and more preferably 20 to 200%. Further preferred.
By using a cured resin film for forming a clad layer having such characteristics in the optical waveguide of the present invention, the interlayer adhesion between the core portion and the clad layer is improved, and a mechanical tensile force is applied to the optical waveguide. Since it is absorbed by the upper and lower cladding layers, the deformation of the core can be reduced, and the deterioration of the transmission characteristics of the film waveguide can be suppressed.

It is preferable to use a resin film for forming a clad layer for at least one of the lower clad layer and the upper clad layer of the optical waveguide of the present invention. The clad layer-forming resin film can be produced using the clad layer-forming resin composition by the same method as the core part-forming resin film.
In addition, there is no restriction | limiting in particular as a support film used in the manufacture process of the resin film for clad layer formation, For example, Polyester, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; Polyolefin, such as polyethylene and a polypropylene; Polycarbonate, polyamide, Examples include polyimide, polyamideimide, polyetherimide, polyethersulfide, polyethersulfone, polyetherketone, polyphenyleneether, polyphenylenesulfide, polyarylate, polysulfone, and liquid crystal polymer. Among these, from the viewpoints of flexibility and toughness, the polyester, polypropylene, polycarbonate, polyamide, polyimide, polyamideimide, polyphenylene ether, polyphenylene sulfide, polyarylate, and polysulfone are preferable.
In addition, you may use the film in which the mold release process was given with the silicone type compound, the fluorine-containing compound, etc. from a viewpoint of peelability improvement with a resin layer as needed.

  The thickness of the support film may be appropriately changed depending on the intended flexibility, but is preferably 3 to 250 μm. When it is 3 μm or more, the film strength is sufficient, and when it is 250 μm or less, sufficient flexibility is obtained. From the above viewpoint, the thickness of the support film is more preferably 5 to 200 μm, and particularly preferably 7 to 150 μm.

The clad layer forming resin film produced by applying the clad layer forming resin composition on the support film is affixed on the resin layer as necessary, and the support film, the resin layer, and the protective film It is good also as a 3 layer structure which consists of.
The clad layer-forming resin film thus obtained can be easily stored, for example, by being rolled up. Moreover, a roll-shaped film can be cut out into a suitable size and stored in a sheet shape.

Hereinafter, the optical waveguide of the present invention will be described.
A sectional view of the optical waveguide is shown in FIG. The optical waveguide 1 is formed on a base material 5 and includes a core part 2 made of a core part-forming resin composition having a high refractive index, a lower clad layer 4 made of a clad layer-forming resin composition having a low refractive index, and The upper clad layer 3 is used.
The core portion forming resin film of the present invention is preferably used for the core portion 2. The clad layer forming resin film is preferably used for at least one of the lower clad layer 4 and the upper clad layer 3.
By using a resin film for forming a clad layer and a resin film for forming a core part in the optical waveguide of the present invention, the flatness of each layer, the interlayer adhesion between the clad and the core, and the resolution at the time of forming the optical waveguide core pattern (thin lines or (Correspondence between narrow lines) can be further improved, flatness is excellent, and it is possible to form a fine pattern with a small line width and line spacing.

  In the optical waveguide 1, the material of the base material 5 is not particularly limited. For example, a glass epoxy resin substrate, a ceramic substrate, a glass substrate, a silicon substrate, a plastic substrate, a metal substrate, a substrate with a resin layer, a substrate with a metal layer, Examples thereof include a plastic film, a plastic film with a resin layer, and a plastic film with a metal layer.

The optical waveguide 1 can be a flexible optical waveguide using a flexible and tough substrate as the substrate 5, for example, a support film of a resin film for forming a clad layer as the substrate. Moreover, you may make the base material 5 function as a protective film of the optical waveguide 1 at this time. By using a support film substrate as the substrate 5, flexibility and toughness can be imparted to the optical waveguide 1. At this time, the clad layer forming resin is preferably formed on a support film that has been subjected to an adhesion treatment. Furthermore, by making the base material 5 function as a protective film, the optical waveguide 1 is not subjected to dirt or scratches, so that the ease of handling is improved.
From the above viewpoint, the base material 5 having a function as a protective film is disposed outside the upper cladding layer 3 as shown in FIG. 1B, or the lower cladding layer 4 as shown in FIG. And the base material 5 which has a function as a protective film may be arrange | positioned on the outer side of both of the upper clad layers 3.
If the optical waveguide 1 has sufficient flexibility and toughness, the substrate 5 having a function as a protective film may not be disposed as shown in FIG.

The thickness of the lower clad layer 4 is not particularly limited, but is preferably 2 to 200 μm. If it is 2 μm or more, it becomes easy to confine the propagating light inside the core, and if it is 200 μm or less, the entire thickness of the optical waveguide 1 is not too large. The thickness of the lower cladding layer 4 is a value from the boundary between the core portion 2 and the lower cladding layer 4 to the lower surface of the lower cladding layer 4.
Although there is no restriction | limiting in particular about the thickness of the resin film for lower clad layer formation, Thickness is adjusted so that the thickness of the lower clad layer 4 after hardening may become said range.

  Although there is no restriction | limiting in particular about the height of the core part 2, It is preferable that it is 10-150 micrometers. When the height of the core is 10 μm or more, the alignment tolerance is not reduced in coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed, and when the core portion is 150 μm or less, the light is received and emitted after the optical waveguide is formed In coupling with an element or an optical fiber, coupling efficiency is not reduced. From the above viewpoint, the height of the core part is more preferably 15 to 130 μm, and particularly preferably 20 to 120 μm. In addition, there is no restriction | limiting in particular about the thickness of the resin film for core part formation, but thickness is adjusted so that the height of the core part after hardening may become said range.

  The thickness of the upper clad layer 3 is not particularly limited as long as the core portion 2 can be embedded, but the thickness after drying is preferably 12 to 500 μm. The thickness of the upper clad layer 3 may be the same as or different from the thickness of the lower clad layer 4 that is formed first, but is thicker than the thickness of the lower clad layer 4 from the viewpoint of embedding the core portion 2. It is preferable. The thickness of the upper cladding layer 3 is a value from the boundary between the core portion 2 and the lower cladding layer 4 to the upper surface of the upper cladding layer 3.

  In the repeated bending test (bending durability test) of the flexible optical waveguide of the present invention, it is preferable that no mechanical breakage occurs in the flexible optical waveguide after the bending test is performed 100,000 times with a curvature radius of 1 to 5 mm, for example, 2 mm. More preferably, no mechanical breakage occurs after the bending test is performed 1 million times. If mechanical breakage does not occur in the optical waveguide, stable optical transmission can be performed for a long period of time. For example, the optical waveguide can be applied to a part that is always movable, such as a hinge part of a mobile phone. In order to reduce the size of the device, it is required that the optical waveguide does not break even at a smaller radius of curvature. From this viewpoint, it is more preferable that no mechanical breakage occurs when the radius of curvature is 0.5 mm. Mechanical breakage can be confirmed by magnifying glass, under a microscope, or by visual observation.

  In the repeated twist test (twist durability test) of the flexible optical waveguide of the present invention, it is preferable that no mechanical breakage occurs in the flexible optical waveguide after the 100,000-time twist test. More preferably, no mechanical breakage occurs after the 1,000,000 times twist test. If mechanical breakage does not occur in the optical waveguide, stable optical transmission can be performed for a long period of time. For example, the optical waveguide can be applied to a part that is always movable, such as a hinge part of a mobile phone. Mechanical breakage can be confirmed by magnifying glass, under a microscope, or by visual observation.

  In the repeated slide test (slide endurance test) of the flexible optical waveguide of the present invention, it is preferable that no mechanical breakage occurs in the flexible optical waveguide after the 100,000 times slide test is performed with a gap of 4 mm. More preferably, no mechanical breakage occurs after the slide test is performed 1 million times. If mechanical breakage does not occur in the optical waveguide, stable optical transmission can be performed for a long period of time. For example, the optical waveguide can be applied to a part that is always movable, such as a hinge part of a mobile phone. Mechanical breakage can be confirmed by magnifying glass, under a microscope, or by visual observation.

  When the film optical waveguide of the present invention preferably has a core portion having a tensile modulus of elasticity of 30 to 5000 MPa or less, the followability at the interface when the film optical waveguide is bent or restored in shape can be improved. it can.

In the optical waveguide of the present invention, the relative refractive index difference between the core portion and the cladding layer is preferably 1 to 10%. When it is 1% or more, the light propagating through the core portion at the time of bending does not leak into the cladding layer. If it is 10% or less, the propagation light does not spread too much at the connection portion such as the optical waveguide and the optical fiber, and the coupling loss does not increase. From the above viewpoint, it is more preferably 1.5 to 7.5%, and particularly preferably 2 to 5%. In addition, the relative refractive index difference was calculated | required by the formula shown below.
Specific refractive index difference (%) = [(refractive index of core part) ² − (refractive index of clad layer) ² ] / [2 × (refractive index of core part) ² ] × 100

  In the optical waveguide of the present invention, the light propagation loss is preferably 0.3 dB / cm or less. If it is 0.3 dB / cm or less, the loss of light becomes small and the intensity of the transmission signal is sufficient. From the above viewpoint, the light propagation loss is more preferably 0.2 dB / cm or less, and further preferably 0.1 dB / cm or less.

The optical waveguide of the present invention is excellent in bending resistance, twisting resistance, slide resistance, transparency, reliability, and heat resistance, and can also be used as an optical transmission line of an optical module. As the form of the optical module, for example, an optical waveguide with an optical fiber in which optical fibers are connected to both ends of the optical waveguide, an optical waveguide with a connector in which connectors are connected to both ends of the optical waveguide, and an optical waveguide and a printed wiring board are combined. Examples include an opto-electric composite substrate, an opto-electric conversion module that combines an optical waveguide, an optical / electric conversion element that converts an optical signal and an electrical signal, and a wavelength multiplexer / demultiplexer that combines an optical waveguide and a wavelength division filter.
In the photoelectric composite substrate, the printed wiring board to be combined is not particularly limited, and examples thereof include a rigid substrate such as a glass epoxy substrate and a ceramic substrate, a flexible substrate such as a polyimide substrate and a polyethylene terephthalate substrate.

  Hereinafter, the manufacturing method for forming the optical waveguide 1 using the resin composition for core part formation or the resin film for core part formation of this invention is demonstrated. In the following description, the clad layer forming resin and the core portion forming resin are collectively referred to as “optical waveguide forming resin”.

  There is no restriction | limiting in particular as a method of manufacturing the optical waveguide 1 of this invention, For example, the resin layer for optical waveguide formation is formed on a base material using the resin composition for optical waveguide formation and / or the resin film for optical waveguide formation. The method of forming and manufacturing is mentioned.

  The substrate used for the production of the optical waveguide of the present invention is not particularly limited, but is a glass epoxy resin substrate, a ceramic substrate, a glass substrate, a silicon substrate, a plastic substrate, a metal substrate, a substrate with a resin layer, a substrate with a metal layer. , A plastic film, a plastic film with a resin layer, a plastic film with a metal layer, and the like.

The method for forming the optical waveguide forming resin layer is not particularly limited. For example, using the optical waveguide forming resin composition, spin coating, dip coating, spraying, bar coating, roll coating, Examples of the coating method include a curtain coating method, a gravure coating method, a screen coating method, and an inkjet coating method.
When the resin composition for forming an optical waveguide is diluted with a suitable organic solvent, a step of drying may be added after forming the resin layer as necessary. Examples of the drying method include heat drying and reduced pressure drying. Moreover, you may use these together as needed.

As another method for forming the optical waveguide forming resin layer, there is a method of forming the optical waveguide forming resin film using the optical waveguide forming resin composition by a laminating method.
Among these, from the viewpoint that an optical waveguide having excellent flatness and having a fine pattern with a small line width and a small line pattern can be formed, a method of producing by a lamination method using a resin film for forming an optical waveguide is preferable.

Hereinafter, although the manufacturing method for forming the optical waveguide 1 using the resin film for optical waveguide formation for a lower clad layer, a core part, and an upper clad layer is demonstrated, this invention is not restrict | limited to this.
First, the resin film for lower clad layer formation is laminated | stacked on the base material 5 as a 1st process. There is no restriction | limiting in particular as the lamination | stacking method in a 1st process, For example, the method of laminating | stacking by crimping, heating using a roll laminator or a flat plate laminator etc. is mentioned. The flat plate laminator in the present invention refers to a laminator in which a laminated material is sandwiched between a pair of flat plates and pressed by pressing the flat plate. For example, a vacuum pressurizing laminator can be suitably used. The heating temperature here is preferably 20 to 130 ° C., and the pressure bonding pressure is preferably 0.1 to 1.0 MPa, but these conditions are not particularly limited. When a protective film exists in the resin film for lower clad layer formation, it laminates | stacks after removing a protective film.

  When laminating using a vacuum pressurizing laminator, a lower clad layer forming resin film may be temporarily pasted onto the substrate 5 in advance using a roll laminator. Here, from the viewpoint of improving adhesion and followability, it is preferable to perform temporary bonding while pressing, and when pressing, a laminator having a heat roll may be used while heating. The laminating temperature is preferably 20 to 130 ° C. When it is 20 ° C. or higher, the adhesion between the resin film for forming the lower clad layer and the substrate 5 is improved, and when it is 130 ° C. or lower, the resin layer does not flow too much at the time of roll lamination, and the required film Thickness is obtained. From the above viewpoint, the laminating temperature is more preferably 40 to 100 ° C. The pressure during lamination is preferably 0.2 to 0.9 MPa, and the lamination speed is preferably 0.1 to 3 m / min, but these conditions are not particularly limited.

The lower clad layer forming resin layer laminated on the substrate 5 is cured by light and / or heat to form the lower clad layer 4. The removal of the support film of the lower clad layer forming resin film may be performed either before or after curing.
The irradiation amount of actinic rays when the lower clad layer-forming resin layer is cured with light is preferably 0.1 to 5 J / cm ² , but there is no particular limitation on this condition. Moreover, when actinic rays permeate | transmit a base material, in order to make it harden | cure efficiently, the double-sided exposure machine which can irradiate actinic rays simultaneously from both surfaces can be used. Moreover, you may irradiate actinic light, heating. In addition, as a process after photocuring, you may perform a 50-200 degreeC heat processing as needed.
The heating temperature when the lower clad layer forming resin layer is cured by heat is preferably 50 to 200 ° C., but this condition is not particularly limited.

When the support film for the resin film for forming the lower clad layer functions as the protective film 5 for the optical waveguide 1, it is cured under the same conditions as described above by light and / or heat without laminating the resin film for forming the lower clad layer. Then, the lower cladding layer 4 may be formed.
In addition, the protective film of the resin film for lower clad layer formation may be removed before hardening, or may be removed after hardening.

  As the second step, a core part-forming resin film is laminated on the lower cladding layer 4 by the same method as in the first step. The core part forming resin layer is designed to have a higher refractive index than the cladding layer forming resin layer.

As a third step, the core portion 2 (core pattern) is exposed. The method for exposing the core 2 is not particularly limited. For example, a method of irradiating actinic rays in an image form through a negative mask pattern called artwork, a direct actinic ray without passing through a photomask using laser direct drawing And the like.
Examples of the active light source include a light source that effectively emits ultraviolet light, such as an ultra-high pressure mercury lamp, a high-pressure mercury lamp, a mercury vapor arc lamp, a metal halide lamp, a xenon lamp, and a carbon arc lamp. Other examples include light sources that effectively emit visible light, such as photographic flood bulbs and solar lamps.

It is preferable that the irradiation amount of the actinic ray at the time of exposing the core part 2 is 0.01-10 J / cm < ² >. When it is 0.01 J / cm ² or more, the curing reaction proceeds sufficiently and the core part 2 is not washed away by development, and when it is 10 J / cm ² or less, the core part 2 becomes thick due to excessive exposure. This is preferable because a fine pattern can be formed. From these viewpoints, the dose of active ray is more preferably from 0.03~5J / cm ^2, and particularly preferably 0.05~3J / cm ^2.
The exposure of the core part 2 may be performed through the support film of the core part forming resin film, or may be performed after removing the support film.

  Moreover, you may perform post-exposure heating as needed from a viewpoint of the resolution of the core part 2 and adhesive improvement after exposure. The time from ultraviolet irradiation to post-exposure heating is preferably within 10 minutes, but this condition is not particularly limited. The post-exposure heating temperature is preferably 40 to 160 ° C., and the time is preferably 30 seconds to 10 minutes, but these conditions are not particularly limited.

As a 4th process, when exposed through the support film of the resin film for core part formation, this is removed and it develops using the developing solution suitable for the composition of the resin layer for core part formation.
The development method is not particularly limited, and examples thereof include a spray method, a dip method, a paddle method, a spin method, a brushing method, and a scraping method. Moreover, you may use these image development methods together as needed.
The developer is not particularly limited, and is an organic solvent-based developer such as an organic solvent or a semi-aqueous developer composed of an organic solvent and water; an alkaline aqueous solution, an alkaline aqueous solution composed of an alkaline aqueous solution and one or more organic solvents. And alkaline developers. The development temperature is adjusted in accordance with the developability of the core portion forming resin layer.

The organic solvent is not particularly limited, and examples thereof include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; chain ethers such as diethyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, and dibutyl ether. Cyclic ethers such as tetrahydrofuran and 1,4-dioxane; alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol, and propylene glycol; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2- Ketones such as pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; ethylene carbonate, propylene carbonate Which carbonic acid ester; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol Polyhydric alcohol alkyl ethers such as monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl Polyhydric alcohol alkyl ether acetates such as ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate; N, N-dimethylformamide, N, Examples include amides such as N-dimethylacetamide and N-methylpyrrolidone.
These organic solvents can be used alone or in combination of two or more. Further, a surface active agent, an antifoaming agent, or the like may be mixed in the organic solvent.

The semi-aqueous developer is not particularly limited as long as it is composed of one or more organic solvents and water.
The concentration of the organic solvent is usually preferably 2 to 90% by mass. Further, a small amount of a surfactant, an antifoaming agent or the like may be mixed in the semi-aqueous developer.

The base of the alkaline aqueous solution is not particularly limited, and examples thereof include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate; Alkali metal bicarbonates such as lithium hydrogen, sodium bicarbonate, potassium bicarbonate; alkali metal phosphates such as potassium phosphate and sodium phosphate; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; Sodium salts such as sodium acid and sodium metasilicate; ammonium salts such as ammonium carbonate and ammonium hydrogen carbonate; tetramethylammonium hydroxide, triethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1 3-propanediol, and organic bases such as 1,3-diamino-propanol-2-morpholine.
These bases can be used alone or in combination of two or more.
The pH of the alkaline aqueous solution used for development is preferably 9-14. Moreover, you may mix surfactant, an antifoamer, etc. in alkaline aqueous solution.

The alkaline quasi-aqueous developer is not particularly limited as long as it is composed of an alkaline aqueous solution and one or more organic solvents. The pH of the alkaline quasi-aqueous developer is preferably as low as possible within a range where development can be sufficiently performed, preferably pH 8 to 13, and more preferably pH 9 to 12.
The concentration of the organic solvent is usually preferably 2 to 90% by mass. Further, a small amount of a surfactant, an antifoaming agent or the like may be mixed in the alkaline quasi-aqueous developer.

As a treatment after development, the organic solvent, a semi-aqueous cleaning solution composed of the organic solvent and water, or water may be used as necessary.
The cleaning method is not particularly limited, and examples thereof include a spray method, a dipping method, a paddle method, a spin method, a brushing method, and a scraping method. Moreover, you may use these washing | cleaning methods together as needed.
The said organic solvent can be used individually or in combination of 2 or more types. In the semi-aqueous cleaning liquid, the concentration of the organic solvent is usually preferably 2 to 90% by mass. The washing temperature is adjusted in accordance with the developability of the core portion forming resin layer.

As processing after development or washing, exposure and / or heating may be performed as necessary from the viewpoint of improving the curability and adhesion of the core portion 2. The heating temperature is preferably 40 to 200 ° C., and the irradiation amount of active light is preferably 0.01 to 10 J / cm ² , but these conditions are not particularly limited.

  As a fifth step, an upper clad layer forming resin film is laminated on the lower clad layer 4 and the core portion 2 by the same method as the first and second steps. Here, the upper clad layer forming resin layer is designed to have a lower refractive index than the core portion forming resin layer. The thickness of the upper clad forming resin layer is preferably larger than the height of the core portion 2.

Next, the upper clad layer-forming resin layer is cured by light and / or heat in the same manner as in the first step to form the upper clad layer 3.
The irradiation amount of the actinic ray when the upper clad layer forming resin layer is cured by light is preferably 0.1 to 30 J / cm ² , but this condition is not particularly limited. Moreover, when actinic rays permeate | transmit a base material, in order to make it harden | cure efficiently, the double-sided exposure machine which can irradiate actinic rays simultaneously from both surfaces can be used. Moreover, you may irradiate actinic light, heating as needed, and you may heat-process as a process after photocuring. The heating temperature during and / or after irradiation with actinic rays is preferably 50 to 200 ° C., but these conditions are not particularly limited.
The heating temperature when the upper clad layer forming resin layer is cured by heat is preferably 50 to 200 ° C., but this condition is not particularly limited.
In addition, when the removal of the support film of the resin film for upper clad layer formation is required, it may remove before hardening or after hardening.
The optical waveguide 1 can be manufactured through the above steps.

  The following examples of the present invention will be described more specifically, but the present invention is not limited to these examples.

Example 1
[Preparation of resin varnish COV-1 for core formation]
As the component (A), 75 parts by mass of a propylene glycol monomethyl ether acetate solution (solid content 40% by mass) of bisphenol A / bisphenol F type phenoxy resin (YP-70 manufactured by Toto Kasei Co., Ltd.) (solid content 30 parts by mass), ( B) As component, 40 parts by mass of ethoxylated bisphenol A diacrylate (A-BPE-10, Shin-Nakamura Chemical Co., Ltd., ethylene oxide group average added mole number 10), ethoxylated fluorene type diacrylate (manufactured by Osaka Gas Chemical Co., Ltd.) EA-0500, ethylene oxide group average addition mole number 5) 30 parts by mass, (C) as component 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-1- On (Ciba Japan Co., Ltd. Irgacure 2959) 1 part by mass, and Bi (2,4,6-trimethylbenzoyl) phenylphosphine oxide after mixing and stirring the (Ciba Japan Co., Ltd. IRGACURE 819) 1 part by mass, vacuum defoamed to obtain a core-forming resin varnish COV-1.

[Preparation of Core Part Forming Resin Film COF-1]
The core part-forming resin varnish COV-1 is applied onto the non-treated surface of a PET film (A1517 manufactured by Toyobo Co., Ltd., thickness 16 μm) using a coating machine (Multicoater TM-MC manufactured by Hirano Techseed Co., Ltd.). , Dried at 80 ° C. for 10 minutes, and then at 100 ° C. for 10 minutes, and then a surface release-treated PET film (A31 manufactured by Teijin DuPont Films Co., Ltd., 25 μm thick) was pasted as a protective film to form a core portion-forming resin film COF-1 Obtained. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine. However, in this example, the thickness after curing is 70 μm for the core portion forming resin film, and for the tensile test. The thickness of the cured film was adjusted to 50 μm.

[Production of cured film for tensile test]
Using a roll laminator (HLM-1500 manufactured by Hitachi Chemical Technoplant Co., Ltd.), the core-forming resin film COF-1 from which the protective film (A31) has been removed, and the core-forming resin film from which the protective film (A31) has been removed. The COF-1 was laminated under the conditions of a pressure of 0.4 MPa, a temperature of 50 ° C., and a speed of 0.4 m / min. Then, ultraviolet rays (wavelength 365 nm) were irradiated with 2000 mJ / cm ² using an ultraviolet exposure machine (Dai Nippon Screen Co., Ltd. MAP-1200-L). After removing the support film (A1517), heat treatment was performed at 160 ° C. for 1 hour to obtain a cured film having a thickness of 100 μm.

[Tensile test]
The obtained cured film (width 10 mm, length 70 mm) was subjected to a tensile test (distance between grips 50 mm) using a tensile tester (RTM-100 manufactured by Orientec Co., Ltd.) at a temperature of 25 ° C. and a tensile speed of 5 mm / min, in accordance with JIS K 7127.
(1) Tensile elongation at break The tensile elongation at break was calculated according to the following formula.
Tensile elongation at break (%) = (distance between grips at break (mm) −initial distance between grips (mm)) ÷ initial distance between grips (mm) × 100
(2) Tensile modulus The tensile modulus was calculated by the following equation using the first linear portion of the tensile stress-strain curve.
Tensile modulus (MPa) = Difference in stress between two points on a straight line (N) ÷ Original average cross-sectional area of cured film (mm ² ) ÷ Difference in strain between the same two points

[Preparation of Clad Layer Forming Resin Varnish CLV-1]
Cyclohexanone solution of epoxy group-containing acrylic rubber (HTR-860P-3 manufactured by Nagase ChemteX Corporation, weight average molecular weight 800,000, solid content 12% by mass) 500 parts by mass (solid content 60 parts by mass), polybutanediol skeleton-containing urethane 20 parts by mass of acrylate (UA-160TM manufactured by Shin-Nakamura Chemical Co., Ltd.), 20 parts by mass of dipentaerythritol hexaacrylate (DPE-6A manufactured by Kyoeisha Chemical Co., Ltd.), 1- [4- (2-hydroxyethoxy) phenyl]- 1 part by mass of 2-hydroxy-2-methyl-1-propan-1-one (Irgacure 2959, manufactured by Ciba Specialty Chemicals Co., Ltd.) and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (Ciba Japan Corporation Irgacure 819) 1 part by mass After stirring and mixing, vacuum defoaming, to obtain a cladding layer-forming resin varnish CLV-1.

[Preparation of Cladding Layer Forming Resin Film CLF-1]
The clad layer forming resin varnish CLV-1 is applied onto the non-treated surface of a PET film (A4100 manufactured by Toyobo Co., Ltd., thickness 50 μm) using a coating machine (Multicoater TM-MC manufactured by Hirano Techseed Co., Ltd.). The film was dried at 100 ° C. for 20 minutes, and then a surface release-treated PET film (A31 manufactured by Teijin DuPont Films Ltd., thickness 25 μm) was attached as a protective film to obtain a resin film CLF-1 for forming a clad layer. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine. In this embodiment, the thickness after curing is 20 μm for the resin film for forming the lower cladding layer, and the upper cladding. In the resin film for layer formation, it adjusted so that it might be set to 80 micrometers.

[Fabrication of optical waveguide]
Using the ultraviolet exposure machine, the lower clad layer forming resin film CLF-1 was irradiated with ultraviolet rays (wavelength 365 nm) at 4000 mJ / cm ² , and then the protective film (A31) was removed to form a lower clad layer.

Subsequently, using the roll laminator, the core part-forming resin film COF-1 from which the protective film (A31) has been removed is placed on the lower cladding layer at a pressure of 0.4 MPa, a temperature of 50 ° C., and a speed of 0.4 m / min. It laminated | stacked on conditions. Next, ultraviolet light (wavelength 365 nm) was irradiated at 1000 mJ / cm ² through a negative photomask having a width of 80 μm using the above-described ultraviolet exposure machine, and then post-exposure heating was performed at 80 ° C. for 5 minutes. After removing the support film (A1517) and developing the core using a developer (propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 70/30 mass ratio), propylene glycol monomethyl ether and then 2-propanol And then dried by heating at 80 ° C. for 10 minutes and at 100 ° C. for 10 minutes.

Next, the upper clad layer forming resin film CLF-1 from which the protective film (A31) has been removed using the vacuum pressurizing laminator is applied to the core and the lower clad layer at a pressure of 0.4 MPa and a temperature of 120 ° C. Lamination was performed under a pressure time of 30 seconds. Ultraviolet rays (wavelength 365 nm) were irradiated at 4000 mJ / cm ² and heat-treated at 120 ° C. for 1 hour to form an upper clad layer. Subsequently, the support film (A4100) of the clad layer forming resin film CLF-1 was removed to obtain an optical waveguide. Thereafter, an optical waveguide having a width of 3 mm and a length of 100 mm was cut out using a dicing saw (DAD-341 manufactured by DISCO Corporation).

[Optical propagation loss measurement]
The optical propagation loss of the obtained optical waveguide is determined by using a VCSEL (FLS-300-01-VCL manufactured by EXFO), a light receiving sensor (Q82214 manufactured by Advantest Corporation), and an incident fiber (GI). -50/125 multimode fiber, NA = 0.20) and outgoing fiber (SI-114 / 125, NA = 0.22), cutback method (measurement waveguide length 10, 5, 3, 2 cm) It was measured by.
A: 0.1 dB / cm or less, B: 0.2 dB / cm or less Δ: 0.3 dB / cm or less, X: larger than 0.3 dB / cm

[Bending durability test]
The bending durability test of the obtained optical waveguide was performed using a bending durability tester (manufactured by Daisho Electronics Co., Ltd.) under the conditions of a bending angle of 0 to 180 °, a bending radius of 2 mm, and a bending speed of 2 times / second. The presence or absence of breakage of the optical waveguide was observed.
A: Not broken after 1,000,000 times, B: Not broken after 500,000 times, Δ: Not broken after 100,000 times, X: Broken after less than 100,000 times

[Twist durability test]
The obtained optical waveguide was subjected to a twisting durability test using a bending durability tester (manufactured by Daisho Electronics Co., Ltd.) under the conditions of a twisting angle of ± 180 °, a distance between grips of 20 mm, and a twisting speed of 0.5 times / second. The endurance test was performed to observe whether the optical waveguide was broken or not.
A: Not broken after 1,000,000 times, B: Not broken after 500,000 times, Δ: Not broken after 100,000 times, X: Broken after less than 100,000 times

[Slide endurance test]
The slide durability test of the obtained optical waveguide was performed using a slide durability tester (manufactured by Daisho Electronics Co., Ltd.) under the conditions of a gap of 4 mm, a slide amount of 20 mm, and a slide speed of 2 times / second. The presence or absence of breakage was observed.
A: Not broken after 1,000,000 times, B: Not broken after 500,000 times, Δ: Not broken after 100,000 times, X: Broken after less than 100,000 times

Examples 2 to 7 and Comparative Example 1
Resin varnishes COV-2 to 8 for forming a core part were prepared according to the blending ratio shown in Table 1, and resin films COF-2 to 8 for forming a core part were produced in the same manner as in Example 1.
Then, the optical waveguide was produced by the same method as Example 1 using these core part formation resin films COF-2-8.

* 1: Propylene glycol monomethyl ether acetate solution of bisphenol A / bisphenol F type phenoxy resin (manufactured by Tohto Kasei Co., Ltd.) * 2: Ethoxylated bisphenol A diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., ethylene oxide group average added mole number 10) )
* 3: Ethoxylated fluorene diacrylate (Osaka Gas Chemical Co., Ltd., ethylene oxide group average added mole number 5)
* 4: Ethoxylated fluorene diacrylate (Osaka Gas Chemical Co., Ltd., ethylene oxide group average added mole number 10)
* 5: Bisphenol A type epoxy acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
* 6: 2-hydroxy-3- (o-phenylphenoxy) propyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
* 7: Propylene glycol monomethyl ether acetate solution of ethoxylated fluorene diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., ethylene oxide group average added mole number 2, solid content 70 mass%)
* 8: 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (Ciba Japan Co., Ltd.)
* 9: Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (Ciba Japan Co., Ltd.)

Moreover, the optical propagation loss measurement of the obtained optical waveguide (width 3mm, length 100mm), the bending durability test, the twisting durability test, and the slide durability test were implemented on the same conditions as the above.
The results are shown in Table 2.

* 1: ◎ ... 0.1 dB / cm or less, ◯ ... 0.2 dB / cm or less, △ ... 0.3 dB / cm or less, x ... greater than 0.3 dB / cm * 2: ◎ ... break after 1 million cycles No, ○… No break after 500,000 times, Δ… No break after 100,000 times, ×… Breakage less than 100,000 times

  From Table 1, the cured film of the resin composition for forming a core part of the present invention has a high tensile elongation at break and a low tensile elastic modulus. For this reason, from Table 2, optical waveguides manufactured using these are excellent in bending durability, twisting durability, and sliding durability while satisfying a light propagation loss of 0.3 dB / cm or less that is practically required. You can see that

  The optical waveguide using the resin composition for forming a core part of the present invention has excellent bending durability, twisting durability, and sliding durability due to the above configuration. Therefore, it can be applied to a wide range of fields such as optical interconnection.

It is sectional drawing explaining the form of the optical waveguide of this invention.

Explanation of symbols

1. 1. Optical waveguide 2. Core part 3. Upper clad layer 4. Lower clad layer Base material

Claims (21)

  An optical waveguide comprising (A) a base polymer, (B) a (meth) acrylate having an average number of added moles of ethylene oxide groups and / or propylene oxide groups of 4 to 30 mol in total, and (C) a radical photopolymerization initiator. A resin composition for forming a core part.   (B) The resin composition for forming a core part according to claim 1, wherein the (meth) acrylate having an average added mole number of ethylene oxide groups and / or propylene oxide groups of 4 to 30 moles is an aromatic (meth) acrylate. object. (B) The (meth) acrylate having a total added mole number of ethylene oxide groups and / or propylene oxide groups of 4 to 30 moles is an aromatic (meth) acrylate represented by the following general formula (1): 3. The resin composition for forming a core part according to 1 or 2.

(Wherein R ¹ is a single bond, or

A represents an integer of 2 to 10. R ^{2 to} R ⁵ each independently represent a hydrogen atom or an organic group having 1 to 20 carbon atoms. R ⁶ and R ⁷ are each independently at least one divalent group selected from the group consisting of —CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ — and —CH ₂ CH (CH ₃ ) —. Indicates. b and c each independently represent an integer of 1 or more, and b + c represents an integer of 4 to 30. )   The blending amount of the (A) base polymer is 10 to 80% by mass with respect to the total amount of the (A) component and the total (meth) acrylate component in the core portion forming resin composition, and (B) ethylene oxide. The blending amount of the (meth) acrylate having a total number of added moles of groups and / or propylene oxide groups of 4 to 30 moles is 10 to 90 relative to the total amount of the component (A) and the total (meth) acrylate component. The blending amount of (C) the polymerization initiator is 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the total (meth) acrylate component. The resin composition for core part formation in any one of -3.   Furthermore (D) The resin composition for core part formation in any one of Claims 1-4 containing the (meth) acrylate which has a hydroxyl group.   (D) The resin composition for forming a core part according to claim 5, wherein the (meth) acrylate having a hydroxyl group is an aromatic (meth) acrylate.   (D) The resin composition for core part formation of Claim 5 or 6 whose (meth) acrylate which has a hydroxyl group is monofunctional (meth) acrylate.   (D) The compounding quantity of the (meth) acrylate which has a hydroxyl group is 10-80 mass% with respect to the total amount of the (A) component and all the (meth) acrylate components in the said resin composition for core part formation. Item 8. The resin composition for forming a core part according to any one of Items 5 to 7.   (A) The base polymer is a phenoxy resin containing at least one selected from the group consisting of bisphenol A, bisphenol A type epoxy compound, bisphenol F, bisphenol F type epoxy compound and derivatives thereof as a constituent unit of the copolymer component. The resin composition for core part formation in any one of Claims 1-8.   The resin composition for core part formation according to any one of claims 1 to 9, wherein the cured film formed by curing the resin composition for core part formation has a tensile elongation at break at 25 ° C of 2.5% or more. object.   The resin composition for core part formation according to claim 10, wherein the cured film formed by curing the resin composition for core part formation has a tensile elastic modulus at 25 ° C of 30 to 5000 MPa.   The resin composition film for core part formation using the resin composition for core part formation in any one of Claims 1-11.   The optical waveguide by which the core part was formed with the resin composition for core part formation in any one of Claims 1-11.   An optical waveguide having a core portion formed by the resin composition film for forming a core portion according to claim 12.   An optical waveguide in which the core portion is formed between a lower cladding layer and an upper cladding layer, wherein the cladding layer is formed of a resin composition having a refractive index lower than that of the core portion, and the ratio of the core portion to the cladding layer. The optical waveguide according to claim 13 or 14, wherein the refractive index difference is 1 to 10%.   The optical waveguide according to any one of claims 13 to 15, wherein the optical waveguide is not broken after performing a bending durability test with a bending radius of 2 mm 100,000 times.   The optical waveguide according to any one of claims 13 to 16, wherein the optical waveguide is not broken after conducting a twisting durability test 100,000 times.   The optical waveguide according to any one of claims 13 to 17, wherein the optical waveguide is not broken after a slide durability test with a gap of 4 mm is performed 100,000 times.   At least one of the upper cladding layer and the lower cladding layer uses a resin composition for forming a cladding layer containing (A ′) an elastomer, (B ′) (meth) acrylate, and (C ′) a polymerization initiator. The optical waveguide according to claim 13, wherein the optical waveguide is formed.   The optical waveguide according to claim 19, wherein (A ′) the elastomer includes acrylic rubber.   The optical waveguide according to claim 19 or 20, wherein (B ') (meth) acrylate contains urethane (meth) acrylate.

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