JP2009134000A - Film-like optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film-like optical waveguide having excellent bending resistance and transparency. <P>SOLUTION: The film-like optical waveguide 24 includes: a lower clad layer 12; a core part 20 formed on the upper face of the lower clad layer 12 and having a specific width; an upper clad layer 22 formed to be laminated on the lower clad layer 12 and the core part 20. At least one of the core part 20, the lower clad layer 12 and the upper clad layer 22 is formed of a photocurable resin composition including, based on 100 parts by mass of the total solid content of the photocurable resin composition, (A) 30-80 parts by mass of a urethane (meth)acrylate oligomer, (B) 10-69 parts by mass of an unsaturated group-containing monomer, and (C) 0.1-10 parts by mass of a photopolymerization initiator. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a film-shaped optical waveguide.

In the multimedia era, optical waveguides are attracting attention as optical transmission media because of the demand for large capacity and high speed information processing in optical communication systems and computers. A typical example of a conventional optical waveguide is a silica-based optical waveguide. However, silica-based optical waveguides require a long process time at a high temperature for the deposition of a quartz film at the time of manufacture. Etching with a high-risk gas is included, and special processes are required for these processes. Many complicated processes and special apparatuses are required, and the yield is low. There are problems such as.
In order to improve these problems, a liquid curable composition is used as a material for the core portion and the cladding layer for the purpose of improving productivity such as reduction in the number of steps of the optical waveguide, shortening of manufacturing time, and increase in yield. A polymer-based optical waveguide to be used has recently been proposed.
As an example, in a polyimide-based optical waveguide whose component is a polyimide obtained from tetracarboxylic dianhydride and diamine, the polyimide is a fluorinated diamine represented by a specific structural formula or a polyimide from a diamine containing the same, or A polyimide optical waveguide characterized by being a mixture thereof has been proposed (Patent Document 1).
This polyimide optical waveguide has good transmission characteristics (low waveguide loss) and has excellent heat resistance.
As another example, (A) a copolymer containing a structural unit having a side chain portion containing a radically polymerizable reactive group bonded via a urethane bond and a structural unit having a side chain that is not polymerizable. A polymer, (B) a compound having one or more ethylenically unsaturated groups in the molecule, a molecular weight of less than 1,000, and a boiling point of 130 ° C. or higher at 0.1 MPa, and (C) a photoradical A photosensitive resin composition for an optical waveguide containing a polymerization initiator has been proposed (Patent Document 2).
According to this photosensitive resin composition, it is possible to form an optical waveguide having high shape accuracy and suppressing deterioration in transmission characteristics under high temperature and high humidity.
Japanese Patent Laid-Open No. 4-9807 JP 2006-146162 A

The conventional optical waveguide has a problem that when it is repeatedly bent in the state of a film-like cured product (film-shaped optical waveguide), breakage or cracks occur, and good transmission characteristics cannot be maintained.
On the other hand, when another member such as a light-emitting element is fixed to the lower surface of the film-shaped optical waveguide, the film-shaped optical waveguide is highly transparent because the film-shaped optical waveguide is seen through from above and aligned. It is desirable to have.
Then, an object of this invention is to provide the film-form optical waveguide excellent in bending durability and transparency.

  As a result of intensive studies to solve the above problems, the present inventor includes a core portion and a cladding layer (lower cladding layer, upper cladding layer), and at least one of the core portion and the cladding layer has a specific component composition. It has been found that the above-mentioned object of the present invention can be achieved by a film-shaped optical waveguide made of a cured product of a photo-curable resin composition having the present invention, and the present invention has been completed.

That is, the present invention provides the following [1] to [4].
[1] A film-shaped optical waveguide comprising a core part and a clad layer, wherein at least one of the core part and the clad layer contains the following components (A) to (C) (however, The following blending amount is a value when the solid content of the photocurable resin composition is 100 parts by mass.) A film-shaped optical waveguide comprising a cured product.
(A) Urethane (meth) acrylate oligomer 30-80 parts by mass (B) Unsaturated group-containing monomer 10-69 parts by mass (C) Photopolymerization initiator 0.1-10 parts by mass [2] Component (A) is The film-like optical waveguide according to the above [1], comprising a urethane (meth) acrylate oligomer that is a reaction product of (a) a polyol compound, (b) a polyisocyanate compound, and (c) a hydroxyl group-containing (meth) acrylate.
[3] (a) The film-shaped optical waveguide according to the above [2], wherein the polyol compound is at least one selected from the group consisting of aliphatic polyether polyol, aromatic polyether polyol, polyester polyol, and polycarbonate polyol. .
[4] The photocurable resin composition does not contain an unsaturated group-containing polymer, or the blending amount is 40 parts by mass or less when the total solid content of the photocurable resin composition is 100 parts by mass. The film-like optical waveguide according to any one of the above [1] to [3], comprising an unsaturated group-containing polymer.
[5] The curable resin composition does not contain an unsaturated group-containing polymer, or contains an unsaturated group-containing polymer, and the blending amount of the unsaturated group-containing polymer is the blending amount of the component (A). The film-like optical waveguide according to any one of the above [1] to [4], which is less than the above.

Since the film-shaped optical waveguide of the present invention includes a core portion and / or a clad layer (a lower clad layer, an upper clad layer) made of a photocurable resin composition having a specific component composition, However, no breakage or cracks occur, and good transmission characteristics can be maintained.
In addition, the film-shaped optical waveguide of the present invention has a highly transparent core part and / or cladding layer made of a photocurable resin composition having a specific component composition. When adhering to this member, the film-like optical waveguide can be seen through and alignment can be performed easily and accurately.

The film-shaped optical waveguide of the present invention includes a core portion and a clad layer (specifically, a lower clad layer and an upper clad layer), and the core portion and / or the clad layer has a specific component composition. It is made of a cured product of the resin composition, and in particular, the cladding layer is made of a cured product of a photocurable resin composition having a specific component composition.
The components (A) to (C) constituting the photocurable resin composition and other components blended as necessary will be described below.

[Component (A)]
Component (A) is a urethane (meth) acrylate oligomer.
The urethane (meth) acrylate oligomer used as the component (A) is produced, for example, by reacting (a) a polyol compound, (b) a polyisocyanate compound, and (c) a hydroxyl group-containing (meth) acrylate. Specifically, it is produced by any one of the following production methods 1 to 4.
Production method 1: A method in which a polyol compound, a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate are charged and reacted together.
Production method 2: A method in which a polyol compound and a polyisocyanate compound are reacted and then a hydroxyl group-containing (meth) acrylate is reacted.
Production method 3: A method in which a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate are reacted, and then a polyol compound is reacted.
Production Method 4: A method in which a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate are reacted, then a polyol compound is reacted, and finally, a hydroxyl group-containing (meth) acrylate compound is reacted again.

Hereinafter, each of (a) a polyol compound, (b) a polyisocyanate compound, and (c) a hydroxyl group-containing (meth) acrylate used for production of a urethane (meth) acrylate oligomer will be described in detail.
[(A) Polyol compound]
(A) As a polyol compound, aliphatic polyether polyol, alicyclic polyether polyol, aromatic polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone polyol, etc. are mentioned.
Examples of the aliphatic polyether polyol include at least one selected from ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, substituted tetrahydrofuran, oxetane, substituted oxetane, tetrahydropyran, and oxeban. Examples thereof include those obtained by ring-opening (co) polymerizing a compound. Specific examples thereof include polyethylene glycol, 1,2-polypropylene glycol, 1,3-polypropylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, polyisobutylene glycol, copolymer polyol of propylene oxide and tetrahydrofuran. Copolymer polyols of ethylene oxide and tetrahydrofuran, copolymer polyols of ethylene oxide and propylene oxide, copolymer polyols of tetrahydrofuran and 3-methyltetrahydrofuran, copolymer polyols of ethylene oxide and 1,2-butylene oxide, etc. Can be mentioned.
Examples of the alicyclic polyether polyol include hydrogenated bisphenol A ethylene oxide addition diol, hydrogenated bisphenol A propylene oxide addition diol, hydrogenated bisphenol A butylene oxide addition diol, and hydrogenated bisphenol F ethylene oxide addition diol. And propylene oxide addition diol of hydrogenated bisphenol F, butylene oxide addition diol of hydrogenated bisphenol F, dimethylol compound of dicyclopentadiene, tricyclodecane dimethanol and the like.

  As commercial products of aliphatic polyether polyol and alicyclic polyether polyol, Unisafe DC1100, Unisafe DC1800, Unisafe DCB1100, Unisafe DCB1800 (above, manufactured by NOF Corporation); PPTG4000, PPTG2000, PPTG1000, PTG2000, PTG3000, PTG650, PTGL2000, PTGL1000 (above, manufactured by Hodogaya Chemical Co., Ltd.); EXENOL 4020, EXENOL 3020, EXENOL 2020, EXENOL 1020 (above, manufactured by Asahi Glass Co., Ltd.); 4200, 6300, 8200 (above, manufactured by Sumika Bayer Urethane Co., Ltd.); NPML-2 02,3002,4002,8002 (above, manufactured by Asahi Glass Co., Ltd.), and the like.

Examples of the aromatic polyether polyol include bisphenol A ethylene oxide addition diol, bisphenol A propylene oxide addition diol, bisphenol A butylene oxide addition diol, bisphenol F ethylene oxide addition diol, bisphenol F propylene oxide addition diol, Examples include butylphenol addition diol of bisphenol F, alkylene oxide addition diol of hydroquinone, alkylene oxide addition diol of naphthoquinone, and the like. Examples of commercially available aromatic polyether polyols include Uniol DA400, DA700, DA1000 (manufactured by NOF Corporation) and the like.
Examples of the polyester polyol include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, and 3-methyl. Polyhydric alcohols such as -1,5-pentanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, Examples thereof include polyester polyols obtained by reacting polybasic acids such as sebacic acid. Commercially available products include Kurapol P-2030, P-1030, P-2010, P-5010, P-2050, F-2010, P-2011, PMIPA, PKA-A, PKA-A2, PNA-2000 (above, Kuraray Co., Ltd.).

Examples of the polycarbonate polyol include 1,6-hexanediol polycarbonate, copolymerized polycarbonate diol of 1,6-hexanediol and 1,5-pentanediol, 3-methyl-1,5-pentanediol and 1,6-hexane. Examples thereof include a copolymer polycarbonate diol with hexanediol, a copolymer polycarbonate diol with 1,3-propanediol and 1,4-butanediol, and the like. Commercially available products include PCDL T5652, G3452, G3450J (Asahi Kasei Co., Ltd.); DN-980, 981, 982, 983 (Nippon Polyurethane Co., Ltd.); Kuraray polyol C-590, C1050, C-1090, C-2050, C-2090, C-3090, C-5090, C-1065N, C-2065N, C-1015N, C-2015N (above, manufactured by Kuraray); PLACEL-CD205, CD-983, CD220 (above, Daicel Chemical Industries) PC-8000 (manufactured by PPG, USA) and the like.
As polycaprolactone polyol, ε-caprolactone, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, 1,6-hexanediol, neopentyl glycol Polycaprolactone diol obtained by reacting with diols such as 1,4-cyclohexanedimethanol and 1,4-butanediol. As a commercial item, PLACC CEL205,205AL, 212,212AL, 220,220AL (above, Daicel Chemical Industries Ltd. make) etc. are mentioned.
Other polyol compounds that can be used in the present invention include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedi Examples include methanol, poly β-methyl-δ-valerolactone, hydroxy-terminated polybutadiene, hydroxy-terminated hydrogenated polybutadiene, castor oil-modified polyol, polydimethylsiloxane-terminated diol compound, and polydimethylsiloxane carbitol-modified polyol.
Among these, aliphatic polyether polyol, aromatic polyether polyol, polyester polyol, and polycarbonate polyol are preferable, and polyester polyol and polycarbonate polyol are more preferable.
(A) A polyol compound may be used independently or may use 2 or more types together.
(A) The polyol compound is preferably at least one selected from the group consisting of an aliphatic polyether polyol, an aromatic polyether polyol, a polyester polyol, and a polycarbonate polyol, and is a polyester polyol and / or a polycarbonate polyol. Is more preferable.

  (A) The number average molecular weight of the polyol compound is preferably 100 to 15,000, more preferably 1,000 to 14,000, and most preferably 1,500 to 12,000. (A) When the number average molecular weight of the polyol compound is less than 100, the Young's modulus at room temperature and low temperature of the clad layer obtained by curing the composition is increased, and a film-like optical waveguide having sufficient bending durability is obtained. I can't. On the other hand, when the number average molecular weight exceeds 15,000, the viscosity of the composition increases, and the applicability may deteriorate.

[(B) Polyisocyanate compound]
(B) Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethylphenylene diisocyanate, 4,4′-biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, methylene bis (4-cyclohexyl isocyanate), 2,2,4-trimethylhexamethylene diisocyanate 1,4-hexamethylene diisocyanate, bis (2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, Examples thereof include polyisocyanate compounds such as tetramethylxylylene diisocyanate. Of these, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and the like are preferable.
(B) A polyisocyanate compound may be used independently or may use 2 or more types together.

[(C) Hydroxyl group-containing (meth) acrylate]
(C) Examples of the hydroxyl group-containing (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenyloxy. Propyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, neo Pentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol pen (Meth) acrylate. Furthermore, the compound obtained by addition reaction of glycidyl group containing compounds, such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth) acrylate, and (meth) acrylic acid is mentioned. Of these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like are preferably used.
(C) The hydroxyl group-containing (meth) acrylate may be used alone or in combination of two or more.

  (A) The blending ratio of each raw material constituting the urethane (meth) acrylate oligomer is, for example, (a) 0.5 to 2 mol of a polyol compound, and (b) with respect to 1 mol of (c) hydroxyl group-containing (meth) acrylate. ) 1 to 2.5 moles of polyisocyanate compound.

  Moreover, the urethane (meth) acrylate oligomer which is a reaction material of a polyisocyanate compound and a hydroxyl-containing (meth) acrylate can also be used as a component (A). In this case, examples of the polyisocyanate compound and the hydroxyl group-containing (meth) acrylate include those similar to the (b) polyisocyanate compound and (c) hydroxyl group-containing (meth) acrylate, respectively.

As a component (A), a urethane (meth) acrylate oligomer may be used individually by 1 type, or may use 2 or more types together.
Component (A) includes a urethane (meth) acrylate oligomer that is a reaction product of (a) a polyol compound, (b) a polyisocyanate compound, and (c) a hydroxyl group-containing (meth) acrylate, from the viewpoint of bending durability. It is preferable.
In component (A), the amount of urethane (meth) acrylate oligomer, which is a reaction product of (a) polyol compound, (b) polyisocyanate compound, and (c) hydroxyl group-containing (meth) acrylate, is determined according to component (A). When the total amount of is 100 parts by mass, it is preferably 50 parts by mass or more, more preferably 60 parts by mass or more.
The number average molecular weight of the component (A) is preferably 100 to 15,000, more preferably 300 to 12,000. If the value is less than 100, the viscosity of the composition becomes too small, and the coatability may be inferior. On the other hand, when the value exceeds 15,000, the viscosity becomes high and handling becomes difficult.
In the photocurable resin composition, the compounding amount of the component (A) is preferably 30 to 80 parts by mass, more preferably 35 to 75 parts by mass based on 100 parts by mass of the total solid content of the photocurable resin composition. Especially preferably, it is 40-70 mass parts. When the blending amount is less than 30 parts by mass, the Young's modulus of the clad layer obtained by curing the composition is increased, and it becomes difficult to form a film-shaped optical waveguide having sufficient bending durability. On the other hand, when the blending amount exceeds 80 parts by mass, the viscosity of the composition increases, and it becomes difficult to form a clad layer having a uniform thickness.

[Component (B)]
Component (B) is an unsaturated group-containing monomer.
As the unsaturated group-containing monomer, a monomer having one ethylenically unsaturated group in the molecule (hereinafter also referred to as a monofunctional monomer), and a monomer having two or more ethylenically unsaturated groups in the molecule (hereinafter referred to as “monofunctional monomer”). Also referred to as a polyfunctional monomer). Examples of the ethylenically unsaturated group include a (meth) acryloyl group and a vinyl group, and a (meth) acryloyl group is more preferable.
Examples of the monofunctional monomer include acryloylmorpholine, dimethylacrylamide, diethylacrylamide, diisopropylacrylamide, isobornyl (meth) acrylate, dicyclopentenyl acrylate, dicyclopentanyl (meth) acrylate, isodecyl (meth) acrylate, lauryl ( (Meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, tricyclodecanyl (meth) acrylate , Diacetone acrylamide, isobutoxymethyl (meth) acrylamide, N-vinyl pyrrolidone, N-vinyl caprolactam, 3-hydroxy Chlohexyl (meth) acrylate, 2-acryloylcyclohexyl succinic acid, phenoxyethyl (meth) acrylate, tribromophenol ethoxy (meth) acrylate, (meth) acrylate of alcohol which is an adduct of phenol ethylene oxide, p-cumylphenol (Meth) acrylate of alcohol which is an adduct of ethylene oxide, 4- (1-methyl-1-phenylethyl) phenoxyethyl (meth) acrylate, (meth) acrylate of alcohol which is an adduct of ethylene oxide of nonylphenol, o-Phenylphenol glycidyl ether (meth) acrylate, hydroxyethylated o-phenylphenol acrylate, 2-methacryloyloxyethylphthalic acid, methoxypolyethylene group Call (meth) acrylate, and the like.
Among these, N-vinyl compounds such as acryloylmorpholine, N-vinylpyrrolidone and N-vinylcaprolactam, and monofunctional (meth) acrylates having an aliphatic hydrocarbon group having 10 or more carbon atoms are preferable.
Here, the aliphatic hydrocarbon group having 10 or more carbon atoms includes straight chain, branched chain, and alicyclic groups. Preferable examples of the monofunctional (meth) acrylate having an aliphatic hydrocarbon group having 10 or more carbon atoms include isobornyl (meth) acrylate, isodecyl (meth) acrylate, and lauryl (meth) acrylate.
Commercially available monofunctional monomers include ACMO, DMAA (manufactured by Kojin Co., Ltd.); New Frontier IBA (Daiichi Kogyo Seiyaku Co., Ltd.); IBXA, IBXMA, ADMA (Osaka Organic Chemical Co., Ltd.); FA511A, FA512A, FA513A (Above, manufactured by Hitachi Chemical Co., Ltd.); light ester M, E, BH, IB-X, HO-MS, HO-HH, L, PO, S, TD, light acrylate LA, SA, EC-A , MTG-A, 130A, PO-A, P-200A, NP-4EA, THF-A, IB-XA, HOA-MS, HOA-MPL, HOA-MPE (above, manufactured by Kyoeisha Chemical Co., Ltd.); Aronix M150 , M156, M5300, TO1315, TO1316 (above, manufactured by Toagosei Co., Ltd.); FA544A, 512M, 512MT, 513M (above, Hitachi Chemical) NK ester A-CMP-1E, A-LEN-10, M-450G, S, S-1800M, S-1800A, PHE-1G, NPA-8E, NPA-5P, NPA-10G, M- 90G, LMA, LA, IB, CB-26, CB-23, CB-1, AMP-60G, AM-30G, A-SA, A-IB, 702A (manufactured by Shin-Nakamura Chemical Co., Ltd.) and the like.

Among the above polyfunctional monomers, monomers having two ethylenically unsaturated groups in the molecule (bifunctional monomer) include, for example, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) Acrylate, 2,2-bis-4 (2-hydroxy-3-acryloxypropylphenyl) propane, ethylene oxide-added bisphenol A type di (meth) acrylate, ethylene oxide added tetrabromobisphenol A type di (meth) acrylate, propylene Oxa Bisphenol A type epoxy di () obtained by epoxy ring-opening reaction between bisphenol A diglycidyl ether and propylene oxide added tetrabromobisphenol A type di (meth) acrylate, bisphenol A diglycidyl ether and (meth) acrylic acid ( Of tetrabromobisphenol A type epoxy di (meth) acrylate, bisphenol F diglycidyl ether and (meth) acrylic acid obtained by epoxy ring-opening reaction of (meth) acrylate, tetrabromobisphenol A diglycidyl ether and (meth) acrylic acid Bisphenol F-type epoxy di (meth) acrylate obtained by epoxy ring-opening reaction, tetrabutyl obtained by epoxy ring-opening reaction of tetrabromobisphenol F diglycidyl ether and (meth) acrylic acid Mo bisphenol F type epoxy di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate, 9,9-bis [4- (2-acryloyloxy ethoxy) phenyl] fluorene, and the like.
Among them, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 2,2-bis-4 (2-hydroxy-3-acryloxypropylphenyl) propane, ethylene oxide Addition bisphenol A type di (meth) acrylate, ethylene oxide addition tetrabromobisphenol A type di (meth) acrylate, bisphenol A type epoxy di (meth) obtained by epoxy ring-opening reaction of bisphenol A diglycidyl ether and (meth) acrylic acid ) Acrylate, tetrabromobisphenol A type epoxy di (meth) acrylate, 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene and the like are particularly preferably used.

Commercially available products of bifunctional monomers include, for example, Biscoat # 700, # 540 (above, manufactured by Osaka Organic Chemical Industry); Aronix M-208, M-210, M-215 (above, manufactured by Toagosei Co., Ltd.); NK Esters BPE-100, BPE-200, BPE-500, A-BPE-4, A-BPEF (above, manufactured by Shin-Nakamura Chemical Co., Ltd.); Light acrylate 1,6-HX-A, Light ester BP-4EA, BP- 4PA, epoxy ester 3002M, 3002A, 3000M, 3000A (above, manufactured by Kyoeisha Chemical Co., Ltd.); KAYARAD
R-551, R-712 (above, Nippon Kayaku Co., Ltd.); BPE-4, BPE-10, BR-42M (above, Daiichi Kogyo Seiyaku Co., Ltd.); Lipoxy VR-77, VR-60, VR- 90, SP-1506, SP-1506, SP-1507, SP-1509, SP-1563 (manufactured by Showa Polymer Co., Ltd.); Neopole V779, Neopole V779MA (manufactured by Nippon Yupica), and the like.

Among the polyfunctional monomers, examples of the monomer having three or more ethylenically unsaturated groups (trifunctional or higher monomer) include, for example, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, caprolactone-modified tris. (2-hydroxyethyl) isocyanurate tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide (hereinafter referred to as “EO”) modified trimethylolpropane tri (meth) acrylate, propylene oxide (hereinafter referred to as “PO”) .) Modified trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, 2,2,2-tris (meth) acryloyloxymethyl ethyl ester Phosphoric acid, 2,2,2-tris (meth) acryloyloxymethylethylsuccinic acid, EO-modified tris (acryloxy) isocyanurate, caprolactone-modified tris- (2-acryloxyethyl) isocyanurate, tris (acryloxy) isocyanurate , Pentaerythritol tetra (meth) acrylate, PO-modified pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, EO-modified dipenta Erythritol hexa (meth) acrylate, PO-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate Caprolactone-modified dipentaerythritol penta (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, tri methacryloyloxyethyl phosphate, and the like.
Among these, EO-modified trimethylolpropane tri (meth) acrylate, tris (acryloxy) isocyanurate, and dipentaerythritol hexa (meth) acrylate are preferable.

Commercially available products of trifunctional monomers include, for example, Aronix M-315, M-325, M-327, TO-756, TO-1382 (manufactured by Toagosei Co., Ltd.), NK ester TM-4EL, CBX-O, CBX- 1N, A-DPH-6H, A-9300, A-DPH, A-9300-1CL, TMPT, TMPT-9EO, ATM-4P, ATM-4E, ATM-35E, AD-TMP, A-TMPT, A- TMPT-3EO, A-TMPT-3PO, A-TMMT, A-TMM-3LMN (manufactured by Shin-Nakamura Chemical Co., Ltd.), light ester TMP, light acrylate TMP-A, TMP-6EO-3A, PE-3A, PE- 4A, DPE-6A, BA-134, TMP-3EO-A (manufactured by Kyoeisha Chemical Co., Ltd.), Biscoat 295, 360, 3PA, 400 (Osaka Yu Chemical Co., Ltd.), KAYARAD PET-30, DPHA (manufactured by Nippon Kayaku Co., Ltd.).
Further, polyether acrylic oligomer, polyester acrylic oligomer, polycarbonate acrylic oligomer, or polyepoxy acrylic oligomer having polyether, polyester, and polycarbonate in the main chain can also be used.

As the component (B), any of the monofunctional monomer and the polyfunctional monomer may be used alone or in combination.
In the photocurable resin composition, the compounding amount of the component (B) is 10 to 69 parts by mass, preferably 20 to 65 parts by mass, more preferably 100 parts by mass based on the total solid content of the photocurable resin composition. Is 25-60 parts by mass. When the amount of component (B) is less than 10 parts by mass, the moisture and heat resistance of the cured product is lowered, and when the film-shaped optical waveguide is used in a high-temperature and high-humidity atmosphere, the transmission characteristics and the bending durability are favorably maintained. It becomes difficult. On the other hand, when the compounding quantity of a component (B) exceeds 69 mass parts, the photocurability of a composition will fall and it will become difficult to form hardened | cured material (clad layer) which has sufficient mechanical characteristics.

[Component (C)]
Component (C) is a photopolymerization initiator that can generate an active species (radical) capable of polymerizing component (A) and component (B) by light.
Here, light means ionizing radiation such as infrared rays, visible rays, ultraviolet rays, and X-rays, electron beams, α rays, β rays, and γ rays.
Examples of the photopolymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3- Methyl acetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy 2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthate 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like. Among these, 1-hydroxycyclohexyl phenyl ketone and the like are preferably used from the viewpoints of polymerization rate and solution stability.

Examples of commercially available components (C) include Irgacure 184, 369, 379, 651, 500, 819, 907, 784, 2959, CGI-1700, -1750, -1850, CG24-61, Darocur 1116, 1173 (or above). Ciba Specialty Chemicals); Lucirin TPO, LR8883, LR8970 (above, manufactured by BASF); Ubekrill P36 (manufactured by UCB), and the like.
A radical photopolymerization initiator is used individually by 1 type or in combination of 2 or more types.
In the present invention, a photosensitizer can be used together with a photopolymerization initiator. Examples of the photosensitizer include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and 4-dimethylaminobenzoic acid. Isoamyl etc. are mentioned. Examples of commercially available photosensitizers include Ubekryl P102, 103, 104, and 105 (above, manufactured by UCB).

  In the photocurable composition, the compounding amount of the component (C) is 0.1 to 10 parts by mass, preferably 0.2 to 7 parts by mass, with the total solid content of the photocurable composition being 100 parts by mass. More preferably, it is 0.5-5 mass parts. When the blending amount is less than 0.1 parts by mass, curing may not proceed sufficiently, and it may be difficult to form a cured product (core portion and / or cladding layer) having sufficient mechanical properties. Moreover, when the said compounding quantity exceeds 10 mass parts, a photoinitiator may have a bad influence on the long-term characteristic of hardened | cured material.

[Optional ingredients]
[Component (D)]
An organic solvent (component (D)) can be mix | blended with a photocurable resin composition as needed. By blending an organic solvent, an appropriate viscosity can be imparted to form a core portion and / or a clad layer having a uniform thickness.
The type of the organic solvent can be appropriately selected within a range that does not impair the object and effect of the present invention, but has a boiling point within the range of 50 to 200 ° C. under atmospheric pressure, and each constituent component Those that dissolve uniformly are preferred.
Preferable examples of the organic solvent include alcohols, ethers, esters, and ketones. The preferred compound name of the organic solvent is at least one selected from the group consisting of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, diethylene glycol dimethyl ether, methyl isobutyl ketone, methyl amyl ketone, toluene, xylene, and methanol. A solvent is mentioned.
The blending amount of the organic solvent is preferably 5 to 500 parts by mass, more preferably 10 to 300 parts by mass, and particularly preferably 20 to 200 parts by mass based on 100 parts by mass of the total solid content of the photocurable resin composition. is there. If the amount is less than 5 parts by mass, it may be difficult to adjust the viscosity of the photocurable resin composition. When the amount exceeds 500 parts by mass, it may be difficult to form a core portion and / or a cladding layer having a sufficient thickness.

[Component (E)]
It is preferable that the photocurable resin composition does not contain an unsaturated group-containing polymer (component (E)) or a small amount even if it is contained.
Moreover, when an unsaturated group containing polymer (component (E)) is included, it is preferable that the compounding quantity of a component (E) is less than the compounding quantity of a component (A).
In the photocurable resin composition, the blending ratio of the unsaturated group-containing polymer is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 100 parts by mass of the solid content of the photocurable resin composition. Is 20 parts by mass or less, particularly preferably 10 parts by mass or less. When the said mixture ratio exceeds 40 mass parts, bending durability may fall.
In addition, an unsaturated group containing (meth) acrylate type polymer is mentioned as an example of an unsaturated group containing polymer.
Here, examples of the “unsaturated group” in the unsaturated group-containing (meth) acrylate polymer include ethylenically unsaturated groups such as a (meth) acryloyl group and a vinyl group.
In addition, the “(meth) acrylate” in the unsaturated group-containing (meth) acrylate polymer means a (meth) acrylate such as methyl (meth) acrylate, n-butyl (meth) acrylate or the like constituting the polymer. It means that it is used at a content of 50% by mass or more in the total amount of the monomer.

（式中、Ｒ^１及びＲ^２は各々独立して水素原子またはメチル基であり、Ｒ^３は（メタ）アクリロイル基であり、Ｘは２価の有機基であり、Ｙは重合性を有しない有機基である。） An example of the unsaturated group-containing polymer is a polymer (for example, a random copolymer) including a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2). Can be mentioned.

(Wherein R ¹ and R ² are each independently a hydrogen atom or a methyl group, R ³ is a (meth) acryloyl group, X is a divalent organic group, and Y is not polymerizable. Organic group.)

As the unsaturated group-containing polymer, for example, after radical polymerization of a radical polymerizable compound having a hydroxyl group and a radical polymerizable compound corresponding to the general formula (2) in the presence of a catalyst for radical polymerization in a solvent, What was obtained by adding the isocyanate which has a (meth) acryloyloxy group with respect to the hydroxyl group of the side chain of the obtained copolymer is mentioned.
Examples of the radical polymerizable compound having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and the like.
Examples of the radical polymerizable compound corresponding to the general formula (2) include dicyclopentanyl (meth) acrylate, methyl (meth) acrylate, n-butyl (meth) acrylate, styrene, 4- (1-methyl- 1-phenylethyl) phenoxyethyl acrylate, α-methylstyrene and the like.
Examples of the isocyanate having the (meth) acryloyloxy group include 2-methacryloxyethyl isocyanate.
The polystyrene-converted weight average molecular weight of the unsaturated group-containing polymer is preferably 5,000 to 100,000, more preferably 8,000 to 70,000, and particularly preferably 10,000 to 50,000.

  In the photocurable resin composition of the present invention, in addition to the above-described components, for example, polymerizable reactions other than the components (A) to (E), for example, within a range that does not impair the characteristics of the resin composition of the present invention. Group-containing compounds and polymer resins (for example, epoxy resins, acrylic resins, polyamide resins, polyamideimide resins, polyurethane resins, polybutadiene resins, polychloroprene resins, polyether resins, polyester resins, styrene-butadiene block copolymers, Petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine-based polymer, silicone-based polymer) and the like can be blended.

Furthermore, the photo-curable resin composition of the present invention includes, as necessary, various additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, a silane coupling agent, a coating surface improver, and a thermal polymerization inhibitor. , Leveling agents, surfactants, colorants, storage stabilizers, plasticizers, lubricants, fillers, inorganic particles, anti-aging agents, wettability improvers, antistatic agents, and the like.
In order to prepare the photocurable resin composition, the above-described components may be mixed and stirred according to a conventional method.

Next, an example of the film-like optical waveguide of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view schematically showing an example of the film-like optical waveguide of the present invention.
FIG. 2 is a flowchart showing an example of the method for producing a film-shaped optical waveguide of the present invention.

[Structure of film-shaped optical waveguide]
In FIG. 1, a film-like optical waveguide 24 is composed of a core portion 20 and clad layers (lower clad layer 12 and upper clad layer 22). The lower cladding layer 12 is formed by being laminated on the upper surface of the substrate 10, and a core portion 20 having a specific width is formed on the upper surface of the lower cladding layer 12. An upper clad layer 22 is laminated on the upper surfaces of the core portion 20 and the lower clad layer 12. The core portion 20 is embedded in the lower cladding layer 12 and the upper cladding layer 22 that form the outer shape of the optical waveguide 24.
In the present invention, at least one of the core portion 20, the lower clad layer 12, and the upper clad layer 22 is made of a cured product of the above-described photocurable resin composition. In the present invention, both the lower clad layer 12 and the upper clad layer 22 are preferably made of a cured product of the above-described photocurable resin composition, and more preferably, the core portion 20, the lower clad layer 12, and the upper clad layer 22. All of these are preferably made of a cured product of the above-described core-forming photocurable resin composition.
The thickness of each of the lower cladding layer 12 and the upper cladding layer 22 is not particularly limited, but is, for example, 1 to 200 μm, preferably 1 to 50 μm, more preferably 1 to 25 μm, and particularly preferably 1 to 15 μm. . Although the thickness of the core part 20 is not specifically limited, For example, it is 1-200 micrometers, Preferably it is 1-150 micrometers, More preferably, it is 1-100 micrometers, Especially preferably, it is 1-70 micrometers. Although the width | variety of the core part 20 is not specifically limited, For example, it is 1-200 micrometers.
The refractive index of the core portion 20 needs to be larger than any of the refractive indexes of the lower cladding layer 12 and the upper cladding layer 22. For example, for light having a wavelength of 400 to 1,600 nm, the refractive index of the core portion 20 is 1.420 to 1.650, and the refractive indexes of the lower cladding layer 12 and the upper cladding layer 22 are 1.400 to 1.648. In addition, it is preferable that the refractive index of the core portion 20 is at least 0.1% larger than the refractive index of any of the two cladding layers.

The core portion 20 and the clad layer (the lower clad layer 12 and the upper clad layer 22) have high transparency. Specifically, when the core portion and the cladding layer have a thickness of 10 μm, they have a transmittance of 80% or more, preferably 90% or more, for light having a wavelength of 405 nm.
An interface that converts electrical / optical signals by bonding a light emitting element such as a surface emitting laser or a light receiving element such as a photodiode to the lower surface of the film-like optical waveguide by having high transparency in the core portion and the cladding layer. When the film-shaped optical waveguide is formed, the position of the light-emitting element and the light-receiving element can be accurately aligned with the position of the core portion in the film-shaped optical waveguide by seeing through the film-shaped optical waveguide from above.
In addition, since the core portion and the cladding layer have high transparency, a high transmittance can be expressed for light in the wavelength region used for the optical signal, and the optical signal from the light emitting element passes through the cladding layer. Thus, the loss of light when reaching the core portion and the loss of light when the optical signal from the core portion reaches the light receiving element through the cladding layer can be extremely reduced.

[Method for producing film-shaped optical waveguide]
The method for manufacturing the film-shaped optical waveguide 24 of the present invention includes a step of forming the lower clad layer 12, a step of forming the core portion 20, and a step of forming the upper clad layer 22.
In addition, the photocurable resin composition for forming each part of the lower clad layer 12, the core part 20, and the upper clad layer 22 constituting the optical waveguide is respectively, for convenience, a lower layer composition, a core composition, This is referred to as an upper layer composition.
(1) Preparation of photocurable resin composition The component composition of each of the lower layer composition and the upper layer composition is not particularly limited, but is the same photocurable resin composition in terms of economy and production management. It is preferable that it is a thing.
The viscosity of the lower layer composition and the upper layer composition is preferably 1 to 10,000 cps (25 ° C.), more preferably 5 to 8,000 cps (25 ° C.), and particularly preferably 10 to 5,000 cps (25 ° C.). It is. When the viscosity is outside this range, it may be difficult to handle the photocurable resin composition or to form a uniform coating film. In addition, a viscosity can be suitably adjusted by changing compounding quantities, such as an organic solvent.
In addition, each component composition of the lower layer composition, the core composition, and the upper layer composition is required for the optical waveguide to have a refractive index relationship between the lower clad layer 12, the core portion 20, and the upper clad layer 22. It is determined so as to satisfy the conditions. Specifically, two or three kinds of photocurable resin compositions are prepared so that the difference in refractive index has an appropriate magnitude, and among these, a photocurable resin composition that gives a cured film having the highest refractive index. Is used as a core composition, and other photocurable resin compositions are used as a lower layer composition and an upper layer composition.

(2) Preparation of Substrate As shown in FIG. 2A, a substrate 10 having a flat surface is prepared. Although it does not specifically limit as a kind of this board | substrate 10, For example, a silicon substrate, a glass substrate, PET film, a polyimide film etc. can be used.

(3) Formation process of lower cladding layer In this process, the lower cladding layer 12 is formed on the upper surface of the substrate 10. Specifically, the lower layer composition is applied to the surface of the substrate 10 and dried or prebaked to form a lower layer thin film. The lower layer thin film is irradiated with light and cured to form a lower clad layer 12 which is a cured body (see (b) in FIG. 2). In the step of forming the lower clad layer 12, it is preferable to irradiate the entire surface of the thin film with light and harden the whole.
As a method for applying the composition for the lower layer, any one of a spin coating method, a dipping method, a spray method, a bar coating method, a roll coating method, a curtain coating method, a gravure printing method, a silk screen method, an ink jet method and the like is used. be able to. Among these, since a thin film for a lower layer having a uniform thickness can be obtained, it is preferable to employ a spin coating method.
In addition, in order to make the rheological properties of the lower layer composition suitable for the coating method, the lower layer composition requires various leveling agents, thixotropic agents, fillers, organic solvents, surfactants, etc. It is preferable to mix according to this. It is preferable to pre-bake the thin film for lower layers which consists of a composition for lower layers at the temperature of 50-150 degreeC as needed for the purpose of removing an organic solvent etc. after application | coating.

The irradiation amount of light when forming the lower cladding layer 12 is not particularly limited, but light having a wavelength of 200 to 450 nm and an illuminance of 1 to 500 mW / cm ² is irradiated with an irradiation amount of 10 to 5,000 mJ / cm. It is preferable to perform exposure by irradiating so as to be ² .
Visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays and the like can be used as the type of light to be irradiated, and ultraviolet rays are particularly preferable. As the light irradiation device, for example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, an excimer lamp or the like is preferably used.
Moreover, at the time of exposure, sclerosis | hardenability can be improved by making exposure atmosphere into nitrogen stream as needed.
Further, after the exposure, a heat treatment (post-bake) can be further performed. Although this heating condition changes with component composition etc. of a photocurable resin composition, it is 30-250 degreeC normally, Preferably it is 50-200 degreeC, More preferably, it is 100-150 degreeC, for example, for 5 minutes-72 hours of heating. Time can be taken. By performing the heat treatment (post-bake), the entire surface of the coating film can be sufficiently cured.
In addition, the coating method of the composition in the formation process of the lower clad layer 12, the amount of light irradiation, the type, the light (ultraviolet) irradiation device, the pre-bake and post-bake conditions, etc. The same applies to.

(4) Core Part Formation Step Next, as shown in FIG. 2C, the core composition is applied to the upper surface of the lower cladding layer 12 and dried or prebaked to form the core thin film 14. To do. Thereafter, as shown in FIG. 2D, the upper surface of the core thin film 10 is irradiated (exposed) with light 16 through a photomask 18 having a predetermined line pattern, for example, according to a predetermined pattern. Do. As a result, only the portion irradiated with light in the core thin film 14 is cured, so that other uncured portions are developed and removed, as shown in FIG. On the lower clad layer 12, the core portion 20 made of a patterned cured film can be formed.
The details of the development processing in this step are as follows.
The development process is carried out in accordance with a predetermined pattern, and for the thin film selectively cured, using the difference in solubility between the cured portion and the uncured portion, only the uncured portion is developed using a developer. The removal is performed. That is, after pattern exposure, the uncured portion is removed and the cured portion is left, resulting in the formation of the core portion.

An organic solvent can be used as the developer used in the development process. Examples of the organic solvent include acetone, methanol, ethanol, isopropyl alcohol, ethyl lactate, propylene glycol monomethyl ether acetate, methyl amyl ketone, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether, and the like.
The development time is usually 30 to 600 seconds. As a developing method, a known method such as a liquid piling method, a dipping method, or a shower developing method can be employed. After the development, the organic solvent is removed by air drying as it is, and a patterned thin film is formed.
After the formation of the patterned thin film (patterning portion), the patterning portion is heat-treated (post-baked). Although this heating condition changes with component composition etc. of a photocurable resin composition, it is 30-250 degreeC normally, Preferably it is 50-200 degreeC, More preferably, it is 100-150 degreeC, for example, for 5 minutes-10 minutes. The heating time of time may be used. By performing the heat treatment (post-bake), the entire surface of the coating film can be sufficiently cured.

In this step, the method of irradiating light according to a predetermined pattern is not limited to the method using the photomask 18 composed of a light transmitting portion and a non-transmitting portion, and for example, any of the methods a to c shown below May be adopted.
a. A method using electro-optical means for forming a mask image composed of a light transmitting region and a light non-transmitting region in accordance with a predetermined pattern using the same principle as that of a liquid crystal display device.
b. A method of irradiating light through an optical fiber corresponding to a predetermined pattern in the light guide member using a light guide member formed by bundling a large number of optical fibers.
c. A method of irradiating a photocurable resin composition while scanning a laser beam or convergent light obtained by a condensing optical system such as a lens or a mirror.

(5) Upper Cladding Layer Forming Step In this step, the upper clad layer 22 is formed on the upper surfaces of the core portion 20 and the lower clad layer 12. Specifically, the upper layer composition is applied to the upper surfaces of the core portion 20 and the lower cladding layer 12, dried or prebaked to form an upper layer thin film, and the upper layer thin film is irradiated with light and cured. Then, the upper cladding layer 22 which is a cured body is formed (see FIG. 2F). In the step of forming the upper clad layer 22, it is preferable to irradiate the entire surface of the thin film with light and harden the whole. After the exposure, a heat treatment (post-bake) may be further performed.
As described above, the upper-layer composition coating method, pre-bake conditions, light irradiation amount and type, light irradiation apparatus, post-bake conditions, and the like when forming the upper cladding layer 22 are as described above. This is the same as the formation process of the lower cladding layer 12.
Thereafter, when the substrate 10 is not peeled off as it is ((f) in FIG. 2), or when the substrate 10 is peeled off (not shown), a film-like optical waveguide 24 is obtained.

Hereinafter, the present invention will be specifically described by way of examples.
[1. Preparation of photocurable resin composition for core portion and photocurable resin composition for clad layer]
The following materials were prepared as components (A) to (E).
[Component (A)]
In a reaction vessel equipped with a stirrer, 16.6 parts by mass of isophorone diisocyanate, 74.7 parts by mass of polypropylene glycol having a number average molecular weight of 2,000, 0.01 parts by mass of 2,6-di-t-butyl-p-cresol Was cooled to 5 to 10 ° C. While stirring, 0.05 parts by mass of di-n-butyltin dilaurate was added and the mixture was stirred for 2 hours while adjusting the temperature to be kept at 30 ° C. or lower, and then the temperature was raised to 50 ° C. and further stirred for 2 hours. . Subsequently, 8.7 parts by mass of 2-hydroxyethyl acrylate (the total amount of 100 parts by mass above) was added dropwise, and after completion of the addition, the mixture was reacted at 50 ° C. for 1 hour, further heated to 65 ° C. and reacted for 2 hours. . The reaction was terminated when the residual isocyanate was 0.1% by mass or less to obtain Compound A-1.
Compounds A-2 to A-8 were obtained in the same manner.
Table 1 shows the raw material names and blending amounts used for the production of Compounds A-1 to A-8.

[Component (B)]
(1) N-vinylcaprolactam; V-CAP (trade name) manufactured by ISP
(2) N-vinyl-2-pyrrolidone; V-PYROL (trade name) manufactured by ISP
(3) Isobornyl acrylate; manufactured by Osaka Organic Chemical Industry Co., Ltd., IBXA (trade name)
(4) Bisphenol A EO adduct diacrylate; manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat 700 (trade name)
(5) 2,2-bis-4 (2-hydroxy-3-acryloxypropylphenyl) propane; manufactured by Showa Polymer Co., Ltd., VR-77 (trade name)
(6) 1,6-hexanediol diacrylate; manufactured by Kyoeisha Chemical Co., Ltd., light acrylate 1,6-HX-A (trade name)
(7) 1,9-nonanediol diacrylate; manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat 260 (trade name)
(8) EO-modified trimethylolpropane triacrylate; manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat 360 (trade name)
(9) Tris (acryloxy) isocyanurate; manufactured by Toagosei Co., Ltd., Aronix M-315 (trade name)
(10) Dipentaerythritol hexaacrylate; KAYARAD DPHA (trade name) manufactured by Nippon Kayaku Co., Ltd.
(11) 9,9-bis [4- (2-acryloxyethoxy) phenyl] fluorene; manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-BPEF (trade name)

[Component (C)]
(1) Irgacure 369; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, manufactured by Ciba Specialty Chemicals (2) Irgacure 184; 1-hydroxycyclohexyl phenyl ketone, Ciba Made by Specialty Chemicals

[Component (D)]
(1) Methyl isobutyl ketone; manufactured by Diachemical Co., Ltd. (2) methoxypropyl acetate; manufactured by Daicel Chemical Industries, Ltd., MPGPAC (trade name)

[Component (E)]
Preparation Example 1
A flask equipped with a dry ice / methanol reflux was purged with nitrogen, and then 1.5 g of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator and 90 g of methyl isobutyl ketone as an organic solvent were charged and polymerized. Stir until the initiator is dissolved. Subsequently, 20 g of 2-hydroxyethyl methacrylate, 25 g of dicyclopentanyl acrylate, 40 g of methyl methacrylate, and 15 g of n-butyl acrylate were charged, and then gently stirring was started. Thereafter, the temperature of the solution was raised to 70 ° C., and polymerization was carried out at this temperature for 6 hours. Thereafter, 0.12 g of di-n-butyltin dilaurate and 0.05 g of 2,6-di-t-butyl-p-cresol were charged into the obtained solution, and 23.7 g of 2-methacryloxyethyl isocyanate was stirred. Was added dropwise so that the temperature was kept at 60 ° C. or lower. After completion of the dropwise addition, the mixture was reacted at 60 ° C. for 5 hours to obtain a polymer solution having a methacryl group in the side chain. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After this re-dissolution-coagulation operation was performed three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer E-1.

Preparation Example 2
After replacing the flask equipped with a dry ice / methanol reflux with nitrogen, charge 3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 100 g of methyl isobutyl ketone as an organic solvent until the polymerization initiator is dissolved. Stir. Subsequently, 20 g of 2-hydroxyethyl methacrylate, 10 g of methacrylic acid, 10 g of dicyclopentanyl acrylate, 25 g of styrene, and 35 g of n-butyl acrylate were added, and stirring was started gently. Thereafter, the temperature of the solution was raised to 80 ° C., and polymerization was carried out at this temperature for 6 hours. Thereafter, 0.13 g of di-n-butyltin dilaurate and 0.05 g of 2,6-di-t-butyl-p-cresol were charged into the obtained solution, and 23.7 g of 2-methacryloxyethyl isocyanate was stirred. Was added dropwise so that the temperature was kept at 60 ° C. or lower. After completion of the dropwise addition, the mixture was reacted at 60 ° C. for 5 hours to obtain a polymer solution having a methacryl group in the side chain. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After performing this re-dissolution-coagulation operation three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer E-2.

Preparation Example 3
After replacing the flask equipped with a dry ice / methanol reflux with nitrogen, charge 3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 100 g of methyl isobutyl ketone as an organic solvent until the polymerization initiator is dissolved. Stir. Subsequently, 20 g of 2-hydroxyethyl methacrylate, 25 g of styrene, 5 g of n-butyl acrylate, 35 g of 4- (1-methyl-1-phenylethyl) phenoxyethyl acrylate, and 15 g of methacrylic acid were charged, and then gently stirred. It was. Thereafter, the temperature of the solution was raised to 80 ° C., polymerization was performed at this temperature for 6 hours, and after cooling to room temperature, 23.7 g of 2-methacryloxyethyl isocyanate equivalent to 2-hydroxyethyl methacrylate was added to the resulting solution, 0.13 g of di-n-butyltin dilaurate and 0.05 g of 2,6-di-t-butyl-p-cresol were charged, the temperature of the solution was raised to 60 ° C., and polymerization was performed at this temperature for 6 hours. A polymer solution having a methacryloyl group in the side chain was obtained. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After this re-dissolution / coagulation operation was performed three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer E-3.
Table 2 shows the raw material names and blending amounts used for the production of the copolymers E-1, E-2, and E-3.

  In the blending ratio shown in Table 3, the above-mentioned component (A) (compounds A-1 to A-8) and components (B) to (D) or components (B) to (E) are uniformly mixed, The photocurable resin composition for core part and the photocurable resin composition J-1 to J-11 for clad layers were obtained.

[3. Formation of film-like optical waveguide]
[Example 1]
(1) Formation of lower clad layer The lower layer photocurable resin composition J-1 was applied to the upper surface of a silicon substrate with a spin coater, and then applied to the coating film made of the photocurable resin composition J-1 with a wavelength of 365 nm. Then, ultraviolet rays having an illuminance of 20 mW / cm ² were irradiated for 100 seconds and photocured to form a lower cladding layer having a thickness of 10 μm.
(2) Formation of core part The core part photocurable resin composition J-11 was applied onto the lower clad layer with a spin coater and prebaked at 100 ° C for 10 minutes. Next, an ultraviolet ray having a wavelength of 365 nm and an illuminance of 20 mW / cm ² is irradiated for 75 seconds on a 50 μm-thick coating film made of the photocurable resin composition for the core part through a photomask having a line-shaped pattern having a width of 50 μm. And photocured. And the board | substrate which has the hardened coating film was immersed in the developing solution which consists of acetone, and the unexposed part of the coating film was dissolved. Thereafter, post-baking was performed at 150 ° C. for 1 hour to form a core portion having a line pattern having a width of 50 μm.

(3) Formation of upper clad layer The upper layer photocurable resin composition J-1 is applied to the upper surface of the lower clad layer having the core portion by a spin coater, and then comprises the photocurable resin composition J-1. The coating film was photocured by irradiating ultraviolet rays having a wavelength of 365 nm and an illuminance of 20 mW / cm ² for 100 seconds to form an upper clad layer having a thickness of 10 μm from the upper surface of the core portion.
(4) Exfoliation of substrate Film-like light produced by exfoliating the cured product formed in the above steps (1) to (3) from a substrate and laminating a lower clad layer, a core portion, and an upper clad layer in this order. A waveguide was obtained.

[Examples 2 to 10, Comparative Examples 1 and 2]
A film-like optical waveguide was formed in the same manner as in Example 1 except that the photocurable resin composition for forming the core portion and the clad layer (lower clad layer and upper clad layer) was changed as shown in Table 4. .

[4. Evaluation of film-like optical waveguide]
Film-shaped optical waveguides (Examples 1 to 10, Comparative Examples 1 and 2) were evaluated as follows.
[1. Bending durability]
A bending test was performed on the produced film-shaped optical waveguide (width 5 mm, length 10 cm, thickness 70 μm) in an environment of a temperature of 23 ° C. and a humidity of 50%. The test conditions were a bending angle of ± 135 °, a bending speed of 100 times / minute, a load of 100 g, and a bending radius of 0.5 mm and 1 mm. The number of bendings was bent from the initial 0 degree position (the film-shaped optical waveguide was in a horizontal state) to a +135 degree position, and then bent again to a -135 degree position via the 0 degree position. Thereafter, the operation of returning to the 0 degree position is defined as one time. The number of times until the film-shaped optical waveguide breaks is measured. If the number of flexing times exceeds 100,000, “○” indicates that no breaking or cracking occurs. The number of flexing times exceeds 50,000 times and is within 100,000 times. The case where breakage or cracks occurred was indicated as “Δ”, and the case where breakage or cracks occurred within 50,000 times was indicated as “x”.
[2. transparency]
The transparency of the core part and the cladding layer (thickness: 10 μm) was measured with a spectrophotometer. The case where the transmittance of light at a wavelength of 405 nm was 80% or more was “◯”, and the case where it was less than 80% was “x”.
The results are shown in Table 4.

  Table 4 shows that the film-form optical waveguide (Examples 1-10) of this invention is excellent in bending durability. Moreover, it turns out that the core part and clad layer of the film-form optical waveguide of this invention are excellent in transparency. On the other hand, it can be seen that Comparative Example 1 and Comparative Example 2 in which the amount of component (A) is outside the scope of the present invention are both inferior in bending durability.

It is sectional drawing which shows typically an example of the film-form optical waveguide of this invention. It is a flowchart which shows an example of the manufacturing method of the film-form optical waveguide of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate 12 Lower clad layer 14 Core thin film 16 Light 18 Photomask 20 Core portion 22 Upper clad layer 24 Film-like optical waveguide

Claims (5)

A film-shaped optical waveguide comprising a core part and a clad layer, wherein at least one of the core part and the clad layer comprises the following components (A) to (C): The amount is a value when the total amount of the solid content of the photocurable resin composition is 100 parts by mass.) A film-like optical waveguide comprising a cured product.
(A) Urethane (meth) acrylate oligomer 30-80 parts by mass (B) Unsaturated group-containing monomer 10-69 parts by mass (C) Photopolymerization initiator 0.1-10 parts by mass   The film according to claim 1, wherein the component (A) comprises a urethane (meth) acrylate oligomer which is a reaction product of (a) a polyol compound, (b) a polyisocyanate compound, and (c) a hydroxyl group-containing (meth) acrylate. Optical waveguide.   The film-form optical waveguide according to claim 2, wherein the (a) polyol compound is at least one selected from the group consisting of aliphatic polyether polyols, aromatic polyether polyols, polyester polyols, and polycarbonate polyols.   The photocurable resin composition does not contain an unsaturated group-containing polymer, or is unsaturated with a blending amount of 40 parts by mass or less when the total solid content of the photocurable resin composition is 100 parts by mass. The film-form optical waveguide of any one of Claims 1-3 containing group-containing polymer.   The curable resin composition does not contain an unsaturated group-containing polymer, or contains an unsaturated group-containing polymer, and the blending amount of the unsaturated group-containing polymer is less than the blending amount of the component (A). The film-shaped optical waveguide according to any one of claims 1 to 4, wherein the optical waveguide is a film-shaped optical waveguide.

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