JP5327053B2 - Film optical waveguide - Google Patents

Abstract

Disclosed is a film-shaped optical waveguide having excellent bending durability and transparency. Specifically disclosed is a film-shaped optical waveguide (1) comprising a lower cladding layer (15), a core portion (22), an intermediate cladding layer (36) and an upper cladding layer (33). The lower cladding layer (15) and the upper cladding layer (33) are made of a cured product of a photocurable resin composition which contains, when the solid content of the photocurable resin composition is taken as 100% by mass, 30-80% by mass of a urethane (meth)acrylate oligomer (A), 15-69% by mass of a reactive diluted monomer (B) and 0.1-10% by mass of a photopolymerization initiator (C). The intermediate cladding layer (36) is made of a cured product of a photocurable resin composition which contains, when the solid content of the photocurable resin composition is taken as 100% by mass, 5-80% by mass of a urethane (meth)acrylate oligomer (a), 1-40% by mass of a reactive diluted monomer (b), 0.1-10% by mass of a photopolymerization initiator (c) and 15-75% by mass of a vinyl polymer (d) having an ethylenically unsaturated group.

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-mentioned problems, the inventor includes a lower cladding layer, a core portion, an intermediate cladding layer, and an upper cladding layer, and the lower cladding layer, the intermediate cladding layer, and the upper cladding layer. It has been found that the above-mentioned object of the present invention can be achieved according to a film-shaped optical waveguide comprising a cured product of a photo-curable resin composition having a specific component composition.

That is, the present invention provides the following [1] to [ 2 ].
[1] A film-shaped optical waveguide including a lower cladding layer, a core portion, an intermediate cladding layer, and an upper cladding layer, wherein the lower cladding layer and the upper cladding layer are: (A) (A-1) polyol Compound (A-2) Polyisocyanate compound, and (A-3) Urethane (meth) acrylate oligomer that is a reaction product of hydroxyl group-containing (meth) acrylate, 50% by mass or more in the total amount of component (A) 30 to 80% by mass of urethane (meth) acrylate oligomer contained in a proportion , (B) 15 to 69% by mass of a reactive dilution monomer , and (C) 0.1 to 10% by mass of a photopolymerization initiator , and ( E) A photocurable resin composition for a clad layer which does not contain a vinyl polymer having an ethylenically unsaturated group or contains a blending ratio of 10% by mass or less (however, the composition Each blending ratio of the components (A) to (C) and (E) is a value obtained when the total solid content of the photocurable resin composition for the clad layer is 100% by mass.) The intermediate clad layer comprises: (a) 5 to 80% by mass of urethane (meth) acrylate oligomer, (b) 1 to 40% by mass of reactive dilution monomer, and (c) 0.1 to 10% by mass of photopolymerization initiator. And (e) a photocurable resin composition for an intermediate layer containing 15 to 75% by mass of a vinyl-based polymer having an ethylenically unsaturated group (however, each of the components (a) to (c) and (e) The ratio is a value when the total amount of the solid content of the photocurable resin composition for the intermediate layer is 100% by mass.) A film-like optical waveguide comprising a cured product.
[ 2 ] (A-1) The film form according to [ 1 ], wherein the polyol compound is at least one selected from the group consisting of aliphatic polyether polyols, aromatic polyether polyols, polyester polyols, and polycarbonate polyols. Optical waveguide.

The film-shaped optical waveguide of the present invention includes a lower clad layer, an intermediate clad layer, and an upper clad layer made of a photocurable resin composition having a specific component composition. And good transmission characteristics can be maintained. In addition, the film-shaped optical waveguide of the present invention has a highly transparent clad layer made of a photocurable resin composition having a specific component composition, so that the film-shaped optical waveguide and other members such as light-emitting elements are fixed to each other. In doing so, 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 lower clad layer, a core portion, an intermediate clad layer, and an upper clad layer, and the lower clad layer and the upper clad layer have a specific component composition. It consists of hardened | cured material of a composition (it is also called the photocurable resin composition for clad layers), and the said intermediate | middle clad layer has a specific component composition different from the said photocurable resin composition for clad layers. It consists of the hardened | cured material of a photocurable resin composition (it is also called the photocurable resin composition for intermediate | middle layers). First, the photocurable resin composition for cladding layers will be described.

The photocurable resin composition for clad layers contains components (A) to (C) and other components blended as necessary. Hereinafter, each component will be described in detail.
[Component (A)]
Component (A) is a urethane (meth) acrylate oligomer.
Urethane (meth) acrylate oligomer used as the component (A) is prepared by reacting (A-1) a polyol compound, (A-2) a polyisocyanate compound, and (A-3) a hydroxyl group-containing (meth) acrylate Is done.
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, the (A-1) polyol compound, (A-2) polyisocyanate compound, and (A-3) hydroxyl group-containing (meth) acrylate used for the production of the urethane (meth) acrylate oligomer will be described in detail. [(A-1) Polyol Compound] (A-1) Examples of the polyol compound include aliphatic polyether polyols, alicyclic polyether polyols, aromatic polyether polyols, polyester polyols, polycarbonate polyols, and polycaprolactone polyols. It is done. 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.

Commercial products of aliphatic polyether polyol and alicyclic polyether polyol include Unisafe DC1100, Unisafe DC1800, Unisafe DCB1100, Unisafe DCB1800 (manufactured by NOF Corporation); PPTG4000, PPTG2000, PPTG1000, PTG2000, PTG30
00, PTG650, PTGL2000, PTGL1000 (above, manufactured by Hodogaya Chemical Co., Ltd.); Examples include ACCLAIM 2200, 3201, 4200, 6300, 8200 (manufactured by Sumika Bayer Urethane Co., Ltd.); NPML-2002, 3002, 4002, 8002 (manufactured by Asahi Glass Co., Ltd.).

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-1) A polyol compound may be used independently or may use 2 or more types together. (A-1) 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. More preferably.

(A-1) 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-1) 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 (lower clad layer and upper clad layer) obtained by curing the composition is increased, and sufficient. A film-like optical waveguide having bending durability cannot be obtained. On the other hand, when the number average molecular weight exceeds 15,000, the viscosity of the composition increases, and the applicability may deteriorate.

[(A-2) Polyisocyanate Compound] (A-2) As the polyisocyanate compound, for example, 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, methylenebis (4-cyclohexylisocyanate) ), 2,2,4-trimethylhexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, bis (2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, And polyisocyanate compounds such as hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and tetramethylxylylene diisocyanate. Of these, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and the like are preferable. (A-2) A polyisocyanate compound may be used independently or may use 2 or more types together.

[(A-3) Hydroxyl group-containing (meth) acrylate] (A-3) Examples of the hydroxyl group-containing (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- Hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) Acrylate, 1,6-hexanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol (Meth) acrylate, dipentaerythritol penta (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. (A-3) The hydroxyl group-containing (meth) acrylate may be used alone or in combination of two or more.

(A) The compounding ratio of each raw material which comprises a urethane (meth) acrylate oligomer is (A-1) polyol compound 0.5-2 with respect to 1 mol of (A-3) hydroxyl-containing (meth) acrylate, for example. Mol, (A-2) 1 to 2.5 mol of a polyisocyanate compound.

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) is urethane (A-1), a reaction product of a polyol compound, (A-2) a polyisocyanate compound, and (A-3) a hydroxyl group-containing (meth) acrylate, from the viewpoint of bending durability. meth) acrylate oligomer.
Ratio of urethane (meth) acrylate oligomer which is a reaction product of (A-1) polyol compound, (A-2) polyisocyanate compound and (A-3) hydroxyl group-containing (meth) acrylate in component (A) , when component (a) was 100 mass%, 50 mass% or more, preferably 60 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.
Cladding layer photocurable resin composition, the mixing ratio of the component (A), as 100% by mass of the total amount of the solid content of the cladding layer photocurable resin composition, 30 to 80 wt%, preferably from 35 to It is 75 mass% , More preferably, it is 40-70 mass%. When the blending ratio is less than 30% by mass, the Young's modulus of the clad layer (lower clad layer and upper clad layer) obtained by curing the composition is increased, and a film-like optical waveguide having sufficient bending durability is formed. It becomes difficult. On the other hand, when the blending ratio exceeds 80% by mass, the viscosity of the composition increases, and it becomes difficult to form a clad layer having a uniform thickness.

[Component (B)] The component (B) is a reactive dilution monomer. In the present specification, the reactive diluent monomer refers to a monomer that acts as a diluent (reduces viscosity) to other reactive components capable of photopolymerization. Examples of the reactive dilution monomer include 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 multiple monomers). Also referred to as a functional 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, dimethylacrylamide, 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, tris (2-hydroxyethyl) isocyanurate, 9,9-bis [4- (2-acryloxyethoxy) phenyl] Fluorene, ethylene oxide-added bisphenol A type (Meth) acrylate, ethylene oxide-added tetrabromobisphenol A type di (meth) acrylate, propylene oxide added bisphenol A type di (meth) acrylate, propylene oxide added tetrabromobisphenol A type di (meth) acrylate, bisphenol A diglycidyl ether Bisphenol A-type epoxy di (meth) acrylate obtained by epoxy ring-opening reaction with (meth) acrylic acid, tetrabromobisphenol A obtained by epoxy ring-opening reaction between tetrabromobisphenol A diglycidyl ether and (meth) acrylic acid Type epoxy di (meth) acrylate, bisphenol F type epoxy di (meth) acrylate obtained by epoxy ring-opening reaction between bisphenol F diglycidyl ether and (meth) acrylic acid Rate, tetrabromobisphenol F diglycidyl ether with (meth) tetrabromobisphenol F type epoxy di obtained by an epoxy ring-opening reaction of acrylic acid (meth) acrylate. Among them, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 2,2-bis-4 (2-hydroxy-3-acryloxypropylphenyl) propane, 9-bis [4- (2-acryloxyethoxy) phenyl] fluorene, ethylene oxide-added bisphenol A type di (meth) acrylate, ethylene oxide added tetrabromobisphenol A type di (meth) acrylate, bisphenol A diglycidyl ether and ( Bisphenol A type epoxy di (meth) acrylate, tetrabromobisphenol A type epoxy di (meth) acrylate and the like obtained by epoxy ring-opening reaction with (meth) acrylic acid are particularly preferably used.

As a commercial item of a bifunctional monomer, for example, Biscote # 700, # 540 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.); Aronix M-208, M-210 (above, manufactured by Toagosei Co., Ltd.); , BPE-200, BPE-500, A-BPE-4, A-BPEF (above, Shin-Nakamura Chemical Co., Ltd.); Light acrylate 1,6-HX-A, Light ester BP-4EA, BP-4PA, Epoxy ester 3002M, 3002A, 3000M, 3000A (above, Kyoeisha Chemical Co., Ltd.); KAYARADR-551, R-712 (above, Nippon Kayaku Co., Ltd.); BPE-4, BPE-10, BR-42M (above, Daiichi Kogyo) Manufactured by Pharmaceutical Co., Ltd.); Lipoxy VR-77, VR-60, VR-90, SP-1506, SP-1506, SP-1507, SP-15 9, SP-1563 (manufactured by Showa High Polymer Co., Ltd.); NEOPOL V779, NEOPOL V779MA (manufactured by Japan U-PICA Co., Ltd.), 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 Organic) Manufactured by Manabu Kogyo Co.), KAYARAD PET-30, DPHA (manufactured by Nippon Kayaku Co., Ltd.).

As the component (B), any of the monofunctional monomer and the polyfunctional monomer may be used alone or in combination. Preferably, component (B) contains a polyfunctional monomer. In the photocurable resin composition for the cladding layer, the blending ratio of the component (B) is 15 to 69% by mass, preferably 20 to 66, based on 100% by mass of the total solid content of the photocurable composition for the cladding layer. It is 25 mass%, More preferably, it is 25-60 mass%. When the blending ratio is less than 15% by mass, the heat and moisture resistance of the cured product is lowered, and it is difficult to maintain good transmission characteristics and bending durability when the film-shaped optical waveguide is used in a high-temperature and high-humidity atmosphere. Become. On the other hand, when the blending ratio exceeds 69% by mass, the photocurability of the composition is lowered, and it becomes difficult to form a cured product (lower clad layer, upper clad layer) having sufficient mechanical properties. .

[Component (C)] The component (C) is a photopolymerization initiator capable of generating an active species (radical) capable of polymerizing the component (A) and the 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, diethylthioxan 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, And bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide. 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 (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 for a clad layer, the blending ratio of the component (C) is 0.1 to 10% by mass, preferably 0.1%, based on 100% by mass of the total solid content of the photocurable composition for the clad layer. It is 2-7 mass%, More preferably, it is 0.5-5 mass%. When the blending ratio is less than 0.1% by mass, curing does not proceed sufficiently, and it may be difficult to form a cured product (lower cladding layer, upper cladding layer) having sufficient mechanical properties. Moreover, when the said mixture ratio exceeds 10 mass%, a photoinitiator may have a bad influence on the long-term characteristic of a film-form optical waveguide.

[Arbitrary component] An organic solvent (component (D)) can be mix | blended with the photocurable resin composition for clad layers as needed. By blending an organic solvent, an appropriate viscosity can be imparted and a clad layer having a uniform thickness can be formed. 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 in 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. As a preferable compound name of the organic solvent, 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 weight, more preferably 10 to 300 parts by weight, and particularly preferably 20 to 200 parts by weight based on 100 parts by weight of the total solid content of the photocurable resin composition for the clad layer. Part by mass. If the said compounding quantity is less than 5 mass parts, adjustment of the viscosity of a photocurable resin composition may become difficult. If the blending amount exceeds 500 parts by mass, it may be difficult to form a cured product (lower cladding layer, upper cladding layer) having a sufficient thickness.

Moreover, it is preferable that the photocurable resin composition for clad layers does not contain substantially the vinyl polymer (component (E)) which has an ethylenically unsaturated group.
In addition, a component (E) is a high polymer (polymer), and is not a low polymer (oligomer).
In the photocurable resin composition for the cladding layer, the blending ratio of the vinyl-based polymer having an ethylenically unsaturated group is 10% by mass or less , with the total solid content of the photocurable resin composition for the cladding layer being 100% by mass. The content is preferably 5% by mass or less , more preferably 2% by mass or less, and particularly preferably 0% by mass. If the blending ratio exceeds 10% by mass, the bending durability may be lowered.
The vinyl polymer having an ethylenically unsaturated group includes a structural unit derived from a vinyl group-containing monomer and / or a (meth) acryloyl group-containing monomer, and has an ethylenically unsaturated group in the molecule. A polymer having one or more groups. Examples of the ethylenically unsaturated group include a vinyl group and a (meth) acryloyl group, and a (meth) acryloyl group is preferable.
Specific examples of such vinyl polymers include 2-hydroxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, methyl (meth) acrylate, n-butyl (meth) acrylate, styrene, α-methyl What was obtained by radically polymerizing styrene and the like in the presence of a catalyst for radical polymerization in a solvent and then adding 2-methacryloxyethyl isocyanate to the hydroxyl group of the side chain of the obtained copolymer Is mentioned.

In addition, in the photocurable resin composition for the cladding layer, in addition to the above-described components, for example, polymerization other than the components (A) to (D) is performed as long as the characteristics of the resin composition of the present invention are not impaired. A compound having a reactive reactive group or a polymer resin (for example, epoxy resin, acrylic resin, polyamide resin, polyamideimide resin, polyurethane resin, polybutadiene resin, polychloroprene resin, polyether resin, polyester resin, styrene-butadiene block copolymer) Coal, petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine-based polymer, silicone-based polymer) and the like can be blended.

Furthermore, the photocurable resin composition for the clad layer includes various additives as necessary, for example, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, coating surface improvers, thermal polymerization prohibition. Agents, leveling agents, surfactants, colorants, storage stabilizers, plasticizers, lubricants, fillers, inorganic particles, anti-aging agents, wettability improvers, antistatic agents, and the like can be blended. In order to prepare the photocurable resin composition for a clad layer, the above-described components may be mixed and stirred according to a conventional method.

Next, the photocurable resin composition for intermediate layers will be described.
The photocurable resin composition for the intermediate layer comprises (a) a urethane (meth) acrylate oligomer, (b) a reactive dilution monomer, (c) a photopolymerization initiator, and (e) a vinyl polymer having an ethylenically unsaturated group. , And other optional ingredients formulated as needed.
Hereinafter, each component will be described.

[Component (a)]
Component (a) is a urethane (meth) acrylate oligomer.
As said urethane (meth) acrylate oligomer, the thing similar to the component (A) of the above-mentioned photocurable composition for clad layers is mentioned. In addition, as a urethane (meth) acrylate oligomer of a component (a), it is preferable to use the urethane (meth) acrylate oligomer same as a component (A) on economical and manufacturing control.
In the photocurable resin composition for intermediate layer, the blending ratio of component (a) is 5 to 80% by mass , preferably 10 to 100% by mass , based on the total solid content of the photocurable resin composition for intermediate layer. It is 75 mass% , More preferably, it is 10-70 mass%. If the blending ratio is less than 5% by mass, the Young's modulus of the intermediate 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 ratio exceeds 80 parts by mass, the viscosity of the composition becomes small, and it becomes difficult to form a cured product (intermediate cladding layer) having a uniform thickness.

[Component (b)]
Component (b) is a reactive diluent monomer.
As said reactive dilution monomer, the thing similar to the component (B) of the above-mentioned photocurable composition for cladding layers is mentioned. In addition, as a reactive dilution monomer of a component (b), it is preferable to use the same reactive dilution monomer as a component (B) on economical and manufacturing control.
The intermediate layer photocurable resin composition, the mixing ratio of component (b), the total amount of the solid content of the intermediate layer photocurable resin composition as 100 wt%, 1 to 40 wt%, preferably 3 to 30% by mass, more preferably 5 to 25% by mass. Bending durability etc. can be made more excellent by making the mixture ratio of a component (b) into the said range. When the blending ratio of component (b) exceeds 40% by mass, the viscosity of the composition becomes small, and it becomes difficult to form a cured product (intermediate cladding layer) having a uniform thickness.

[Component (c)]
Component (c) is a photopolymerization initiator.
As said photoinitiator, the thing similar to the component (C) of the above-mentioned photocurable composition for clad layers is mentioned.
The intermediate layer photocurable resin composition, the mixing ratio of the component (c), the total amount of the solid content of the intermediate layer photocurable resin composition as 100 mass%, 0.1 to 10 mass%, preferably It is 0.2-5 mass%. When the blending ratio is less than 0.1% by mass, curing does not proceed sufficiently, and a problem may occur in the transmission characteristics of the optical waveguide. On the other hand, when the said mixture ratio exceeds 10 mass%, a photoinitiator may have a bad influence on a long-term transmission characteristic.

[Component (e)]
Component (e) is a vinyl polymer having an ethylenically unsaturated group.
Component (e) (vinyl-based polymer having an ethylenically unsaturated group) can be polymerized with component (a) and component (b), and by blending component (e), the intermediate layer Applicability can be improved by imparting an appropriate viscosity to the photocurable resin composition.
The component (e) is a high polymer (polymer) and not a low polymer (oligomer).
The vinyl polymer having an ethylenically unsaturated group (hereinafter also simply referred to as a vinyl polymer ) includes a structural unit derived from a vinyl group-containing monomer and / or a (meth) acryloyl group-containing monomer, And it has one or more ethylenically unsaturated groups in a molecule | numerator. Examples of the ethylenically unsaturated group include a vinyl group and a (meth) acryloyl group, and a (meth) acryloyl group is preferable.

（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。） Specific examples of the vinyl polymer include a polymer including a repeating unit represented by the following general formula (1) and a repeating unit represented by the following general formula (2) (for example, a polymer that is a random copolymer). ).

(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.)

（式中、Ｒ^１は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、Ｗ及びＺは各々独立して単結合または２価の有機基である。） Preferable examples of the repeating unit represented by the general formula (1) include a repeating unit represented by the following general formula (3).

(In the formula, R ¹ is a hydrogen atom or a methyl group, R ³ is a (meth) acryloyl group, and W and Z are each independently a single bond or a divalent organic group.)

（式中、Ｒ^４はメチレンまたは炭素数２〜８のアルキレン基である。） 一般式（３）中のＺ（２価の有機基）の例としては、−（ＣＨ₂）_n−Ｏ−（式中、ｎは１〜８の整数である。）等が挙げられる。 Here, examples of W (divalent organic group) in the general formula (3) include a structure represented by the following general formula (4), a phenylene group, and the like.

(In the formula, R ⁴ is methylene or an alkylene group having 2 to 8 carbon atoms.) Examples of Z (divalent organic group) in formula (3) include — (CH ₂ ) _n —O—. (Wherein, n is an integer of 1 to 8).

（式中、Ｒ^５は炭素数１〜２０の直鎖状、分岐状または環状の炭素鎖を有する基である。） Examples of Y in the general formula (2) include a structure represented by the following general formula (5), a phenyl group, a cyclic amide group, a pyridyl group, and the like.

(In the formula, R ⁵ is a group having a linear, branched or cyclic carbon chain having 1 to 20 carbon atoms.)

The weight average molecular weight in terms of polystyrene of the vinyl polymer is preferably 5,000 to 100,000, more preferably 8,000 to 70,000, and particularly preferably 10,000 to 50,000. If the value is less than 5,000, the composition has a low viscosity and a desired film thickness cannot be obtained. If the value exceeds 100,000, the composition has a high viscosity, which causes There are drawbacks such as poor workability.
Examples of the method for producing the vinyl polymer include (e-1) a radical polymerizable compound having a hydroxyl group and (e-2) component (radical polymerizable compound corresponding to the general formula (2)) in a solvent. And (e-3) an isocyanate having a (meth) acryloyl group is added to the side chain hydroxyl group of the obtained copolymer after radical polymerization.
The compounds (e-1) to (e-3) used in this method will be described.

Compound (e-1) (a radically polymerizable compound having a hydroxyl group) reacts with a hydroxyl group in the compound and an isocyanate group (—N═C═O) in compound (e-3) to form a urethane bond ( -NH-COO-) and a structural unit having a side chain portion containing a (meth) acryloyl group derived from the compound (e-3) is used to introduce into the component (e).
Examples of the compound (e-1) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxymethyl (meth) acrylate, 4-hydroxycyclohexyl ( And (meth) acrylate.
A compound (e-1) is used individually by 1 type or in combination of 2 or more types.
The content of the structural unit derived from the compound (e-1) in the vinyl polymer is preferably 3 to 80% by mass, more preferably 7 to 60% by mass, and particularly preferably 10 to 40% by mass.
When the content is less than 3% by mass, curing tends to be insufficient. If the content exceeds 80% by mass, it may be difficult to adjust the refractive index.

The compound (e-2) (compound corresponding to the structure of the general formula (2)) is mainly used for appropriately controlling the mechanical properties and refractive index of the unsaturated group-containing (meth) acrylic polymer. Examples of the compound (e-2) include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) ) (Meth) acrylic acid alkyl esters such as acrylate; esters of (meth) acrylic acid and cyclic hydrocarbon compounds such as dicyclopentanyl (meth) acrylate and cyclohexyl (meth) acrylate; phenyl (meth) acrylate, (Meth) acrylic such as benzyl (meth) acrylate, o-phenylphenol glycidyl ether (meth) acrylate, 4- (1-methyl-1-phenylethyl) phenoxyethyl acrylate, p-cumylphenoxyethylene glycol (meth) acrylate Acid ants Esters; tribromophenol ethoxy (meth) acrylate, 2,2,2-trifluoromethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoro Halogenated (meth) acrylic esters such as pentyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-methoxystyrene Aromatic vinyls such as 1, conjugated diolefins such as 1,3-butadiene, isoprene and 1,4-dimethylbutadiene; nitrile group-containing polymerizable compounds such as acrylonitrile and methacrylonitrile; amide bonds such as acrylamide and methacrylamide Containing polymerizable compound And fatty acid vinyls such as vinyl acetate. Of these, dicyclopentanyl (meth) acrylate, methyl (meth) acrylate, n-butyl (meth) acrylate, styrene, 4- (1-methyl-1-phenylethyl) phenoxyethyl acrylate, α-methylstyrene and the like are preferable. Used. A compound (e-2) is used individually by 1 type or in combination of 2 or more types. The content of the structural unit derived from the compound (e-2) in the unsaturated group-containing (meth) acrylic polymer is preferably 15 to 92% by mass, more preferably 25 to 84% by mass, and particularly preferably 35 to 78%. % By mass. If the content is less than 15% by mass, it may be difficult to adjust the refractive index. If the content exceeds 92% by mass, curing tends to be insufficient.

Examples of the compound (e-3) (isocyanate having a (meth) acryloyl group) include 2-methacryloxyethyl isocyanate, N-methacryloyl isocyanate, methacryloxymethyl isocyanate, 2-acryloxyethyl isocyanate, N-acryloyl isocyanate, Examples include acryloxymethyl isocyanate.
The content of the structural unit derived from the compound (e-3) in the vinyl polymer is preferably 5 to 80% by mass, more preferably 9 to 60% by mass, and particularly preferably 12 to 45% by mass.
When the content is less than 5% by mass, curing tends to be insufficient. If the content exceeds 80% by mass, it may be difficult to adjust the refractive index.

The vinyl-based polymer can include structural units other than the structural units represented by the general formulas (1) and (2). Examples of the compound for introducing such a structural unit (hereinafter referred to as compound (e-4)) include dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate and diethyl itaconate; vinyl chloride, chloride Examples include chlorine-containing polymerizable compounds such as vinylidene. The content of the structural unit derived from the compound (e-4) in the vinyl polymer is preferably 0 to 20% by mass, more preferably 0 to 10% by mass.
In the process of producing the vinyl polymer , various additives such as a thermal polymerization inhibitor, a storage stabilizer, and a curing catalyst can be added during the addition reaction of the compound (e-3).
The thermal polymerization inhibitor is blended in order to suppress a polymerization reaction due to heat. Examples of thermal polymerization inhibitors include pyrogallol, benzoquinone, hydroquinone, methylene blue, tert-butylcatechol, monobenzyl ether, methoxyphenol, amylquinone, amyloxyhydroquinone, n-butylphenol, phenol, hydroquinone monopropyl ether and the like.
Examples of the storage stabilizer include 2,6-di-t-butyl-p-cresol, benzoquinone, p-toluquinone, p-xyloquinone, phenyl-α-naphthylamine and the like.
Examples of the curing catalyst include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioleate, dibutyltin diacetate, tetramethoxytitanium, tetraethoxytitanium and the like.
The total amount of these various additives is usually 10 parts by mass or less, preferably 5 parts by mass or less, with respect to 100 parts by mass of the total amount of the compounds (e-1) to (e-3).

Examples of the solvent that can be used for radical polymerization of the compound (e-1), the compound (e-2), and the compound (e-4) used in the production of the vinyl polymer as described above include methanol, Alcohols such as ethanol, ethylene glycol, diethylene glycol, propylene glycol; cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, pro Alkyl ethers of polyhydric alcohols such as lenglycol monomethyl ether and propylene glycol monoethyl ether; alkyl ethers of polyhydric alcohols such as ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate and propylene glycol monomethyl ether acetate Acetates; aromatic hydrocarbons such as toluene and xylene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol; ethyl acetate, butyl acetate, Ethyl lactate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, 2-hydroxy Ethyl 2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, 3-ethoxy Examples include esters such as methyl propionate.
Of these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones, and esters are preferred.

The glass transition temperature of the vinyl polymer is preferably 20 ° C. or higher and 150 ° C. or lower. At this time, the glass transition temperature is defined as a value obtained by measurement using a differential scanning calorimeter (DSC) which is usually performed. If the temperature is less than 20 ° C., it is difficult to form a cured product (intermediate cladding layer), or stickiness occurs, resulting in poor workability when laminating a dry film. . On the other hand, when the temperature exceeds 150 ° C., the cured product (intermediate clad layer) becomes hard or brittle, and the bending durability may decrease.

In the photocurable resin composition for intermediate layer, the blending ratio of component (e) is 15 to 75 mass%, preferably 20 to 70 mass%, where the solid content of the photocurable resin composition for intermediate layer is 100 mass%. %, Particularly preferably 30 to 70% by mass. If the said mixture ratio is less than 15 mass%, the viscosity of a composition may become small and applicability | paintability may be inferior. On the other hand, if the blending ratio exceeds 75% by mass, the cured product (intermediate clad layer) may become hard or brittle, and the bending durability may decrease.

[Optional Components] An organic solvent (component (d)) can be blended with the intermediate layer photocurable resin composition as necessary. By blending an organic solvent, an appropriate viscosity can be imparted and an intermediate cladding layer having a uniform thickness can be formed. As an organic solvent, the same thing as the component (D) of the above-mentioned photocurable composition for cladding layers 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 with respect to 100 parts by mass of the solid content of the photocurable resin composition for the intermediate layer. It is. If the said compounding quantity is less than 5 mass parts, adjustment of the viscosity of a photocurable resin composition may become difficult. If the blending amount exceeds 500 parts by mass, it may be difficult to form an intermediate cladding layer having a sufficient thickness.

In addition to the component (d) (organic solvent), the intermediate layer photocurable resin composition may have a polymerizable reaction other than the components (a), (b), and ( e ) as necessary. A compound having a group, a polymer resin, various additives, and the like can be blended. Specific examples of the polymer resin and the additive include those exemplified as the optional components of the above-described photocurable resin composition for a clad layer.
In order to prepare the photocurable resin composition for an intermediate layer, the above-described components may be mixed and stirred according to a conventional method.

Next, the photocurable resin composition (hereinafter, also referred to as “core photocurable resin composition”) used for forming the core portion of the film-shaped optical waveguide of the present invention will be described. Suitable examples of the photocurable resin composition for the core include (a) a vinyl polymer having an ethylenically unsaturated group, (b) a urethane (meth) acrylate oligomer, (c) a reactive diluent monomer, and ( D) A photocurable composition containing a photopolymerization initiator.

[Ingredient (I)] Ingredient (
A) is a vinyl polymer having an ethylenically unsaturated group. Examples of the vinyl polymer having an ethylenically unsaturated group include those similar to the component (e) of the above-described intermediate layer photocurable resin composition.

[Component (B)] The component (B) is a urethane (meth) acrylate oligomer. As said urethane (meth) acrylate oligomer, the thing similar to the component (A) of the above-mentioned photocurable resin composition for clad layers is mentioned. In the photocurable resin composition for the core, the amount of component (b) is preferably 10 to 100 parts by weight, more preferably 20 to 80 parts by weight, particularly preferably 100 parts by weight of component (b). 35 to 70 parts by mass. When the blending amount is less than 10 parts by mass, sufficient bending resistance may not be obtained for the cured product (core portion) of the photocurable composition layer. On the other hand, when the said compounding quantity exceeds 100 mass parts, compatibility with a component (I) will worsen, film | membrane roughening may be produced on the surface of a core part, and sufficient transparency may not be obtained.

[Component (C)] The component (C) is a reactive dilution monomer. As said reactive dilution monomer, the thing similar to the component (B) of the above-mentioned photocurable composition for cladding layers is mentioned. In the photocurable resin composition for the core, the amount of the component (c) is preferably 5 to 100 parts by mass, more preferably 10 to 70 parts by mass, particularly preferably 100 parts by mass of the component (b). 20 to 50 parts by mass. When the blending amount is less than 5 parts by mass, the accuracy of the target waveguide shape may be inferior when a film-like optical waveguide is formed. On the other hand, when the said compounding quantity exceeds 100 mass parts, compatibility with a component (I) will worsen and film | membrane roughening may be produced on the surface of the hardened | cured material (core part) of a photocurable resin composition.

[Component (d)] The component (d) is a photopolymerization initiator. As said photoinitiator, the thing similar to the component (C) of the above-mentioned photocurable composition for clad layers is mentioned. In the photocurable resin composition for the core, the mixing ratio of the component (d) is preferably 0.1 to 10% by mass, more preferably 0.1%, based on 100% by mass of the total amount of the photocurable resin composition for the core. 2 to 5% by mass. If the blending ratio is less than 0.1% by mass, curing does not proceed sufficiently and a problem may occur in the transmission characteristics of the film-like optical waveguide. On the other hand, when the said mixture ratio exceeds 10 mass%, a photoinitiator may have a bad influence on a long-term transmission characteristic.

[Optional Components] The core photocurable resin composition may contain an organic solvent (component (e)) as necessary. By blending an organic solvent, an appropriate viscosity can be imparted. As an organic solvent, the same thing as the component (D) of the above-mentioned photocurable composition for cladding layers is mentioned. In the photocurable resin composition for the core, the blending ratio of the component (e) (organic solvent) is preferably 5 to 80% by mass, more preferably 100% by mass based on the total amount of the photocurable resin composition for the core. It is 10-60 mass%, Most preferably, it is 15-55 mass%. If the said mixture ratio is less than 5 mass%, adjustment of the viscosity of a photocurable resin composition may become difficult. On the other hand, if the blending ratio exceeds 80% by mass, it may be difficult to form a film-like optical waveguide having a sufficient thickness.

In addition, the photocurable resin composition for the core includes various additives as necessary, for example, an antioxidant, an ultraviolet absorber, a light stabilizer, a silane coupling agent, a coating surface improver, a thermal polymerization inhibitor, a leveling agent. 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 for the core, 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 and the manufacturing method thereof 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. 4 is a flowchart showing an example of the method for producing a film-shaped optical waveguide of the present invention.

[Structure of Film Optical Waveguide] In FIG. 1, the film optical waveguide 1 includes a lower cladding layer 15, a core portion 22 formed on the lower cladding layer 15, the lower cladding layer 15, and An intermediate cladding layer 36 formed on the side of the core portion 22 so as to have substantially the same thickness as the core portion 22, and an upper cladding layer 33 formed on the core portion 22 and the intermediate cladding layer 36. It includes an optical waveguide body and support films 2 and 3 provided on the upper and lower surfaces of the optical waveguide body. The optical waveguide main body has a three-layer structure of a lower layer made of the lower cladding layer 15, an intermediate layer made of the core portion 22 and the intermediate cladding layer 36, and an upper layer made of the upper cladding layer 33. The lower clad layer 15 is formed by being laminated on the upper surface of the support film 2, and a core portion 22 having a specific width and an intermediate clad layer 36 are formed on the upper surface of the lower clad layer 15. . An upper cladding layer 33 is formed on the upper surfaces of the core portion 22 and the intermediate cladding layer 36, and the support film 3 is provided on the upper surface of the upper cladding layer 33. The core portion 22 is embedded in the lower cladding layer 15, the intermediate cladding layer 36, and the upper cladding layer 33 that form the outer shape of the optical waveguide body. The intermediate clad layer 36 is formed by being laminated on the upper surface of the lower clad layer 15 (excluding the region where the core portion 22 is formed), and has approximately the same height as the core portion 22. The thickness of the lower cladding layer 15, the core portion 22, the intermediate cladding layer 36, and the upper cladding layer 33 in the film-shaped optical waveguide is not particularly limited. For example, the thickness of the lower cladding layer 15 is 1 to 200 μm, and the core portion The thickness of 22 is determined to be 3 to 200 μm, the thickness of the intermediate cladding layer is 3 to 200 μm, and the thickness of the upper cladding layer 33 is 1 to 200 μm. Although the width | variety of a core part is not specifically limited, For example, it is 1-200 micrometers. The lower cladding layer 15 and the upper cladding layer 33 are made of a cured product of the above-described photocurable resin composition for a cladding layer. The intermediate cladding layer 36 is made of a cured product of the above-described intermediate layer photocurable resin composition. It is preferable that the core part 22 consists of hardened | cured material of the above-mentioned photocurable resin composition for cores. In addition, at least one of the lower cladding layer 15, the core portion 22, the intermediate cladding layer 36, and the upper cladding layer 33 is formed using a dry film described later. That is, at least one of these parts is formed by curing a layer made of an uncured photocurable resin composition in the dry film. Particularly preferably, at least the intermediate cladding layer 36 is formed using a dry film.

The refractive index of the core portion 22 needs to be higher than any of the refractive indexes of the lower cladding layer 15, the intermediate cladding layer 36, and the upper cladding layer 33. For example, for light having a wavelength of 400 to 1,600 nm, the refractive index of the core portion 22 is 1.420 to 1.650, and the refractive indexes of the lower cladding layer 15, the intermediate cladding layer 36, and the upper cladding layer 33 are 1. It is preferable that the refractive index of the core portion 22 is 400 to 1.648 and at least 0.1% larger than the refractive index of any of the three cladding layers 14, 33, and 36. The relative refractive index difference Δ between each portion of the lower cladding layer 15, the intermediate cladding layer 36 and the upper cladding layer 33 and the core portion 22 is preferably 1% or more. The relative refractive index difference Δ is expressed by the following formula. Δ = (n ¹ −n ² ) / n ¹ where n ¹ is the refractive index of the core portion 22, and n ² is the refractive index of the cladding layers (lower cladding layer 15, intermediate cladding layer 36, upper cladding layer 33). is there. By doing so, light can be confined in the core portion 22, so that a good optical waveguide can be created.

The clad layers (the lower clad layer 15, the intermediate clad layer 36, and the upper clad layer 33) have high transparency. Specifically, when the cladding layer has a thickness of 10 μm, it has a transmittance of 80% or more, preferably 90% or more, for light having a wavelength of 405 nm. Since the cladding layer has high transparency, a light emitting element such as a surface emitting laser or a light receiving element such as a photodiode is joined to the lower surface of the film-shaped optical waveguide to form an interface for converting an electrical / optical signal. Sometimes, 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 cladding layer has high transparency, it can exhibit high transmittance with respect to light in the wavelength region used for the optical signal, and the optical signal from the light emitting element passes through the cladding layer and passes through the core. The loss of light when reaching the 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.

[Dry Film] Next, a dry film used for producing the film-like optical waveguide of the present invention will be described. In the present specification, the “dry film” includes at least a layer made of an uncured photocurable resin composition (not liquid; for example, a dried product) and a layer made of the photocurable resin composition. And a base film for support. That is, the dry film only needs to include a layer made of an uncured photocurable resin composition and a base film for supporting the layer. (I) A base film and a photocurable resin composition It may be a laminate with a layer (uncured layer) made of a product, or (ii) a layer (cured product layer) made of a cured product of a base film, a photocurable resin composition, and photocured It may be a laminate with a layer (uncured layer) made of a conductive resin composition. Specific examples of the dry film are shown below. As an example of the dry film of (i) above, (a) a laminate of a base film and a layer (uncured layer) made of a photocurable resin composition for the lower cladding layer, (b) a base film, Laminated body with layer (uncured layer) made of photocurable resin composition for core, (c) base film, and layer (uncured layer) made of photocurable resin composition for intermediate cladding layer And (d) a laminate of a base film and a layer (uncured layer) made of a photocurable resin composition for the upper cladding layer. Examples of the dry film (ii) include, for example, (e) a base film, a lower cladding layer (a layer made of a cured product of a photocurable resin composition for the lower cladding layer), and an intermediate cladding layer Laminated body with layer (uncured layer) made of photocurable resin composition, (f) base film, lower clad layer (layer made of cured product of photocurable resin composition for lower clad layer), Laminated body with layer (uncured layer) made of photocurable resin composition for core part, (g) Base film and upper clad layer (made of cured product of photocurable resin composition for upper clad layer) Layer) and a laminate of a layer (uncured layer) made of a photocurable resin composition for the intermediate cladding layer. Moreover, as a dry film, (h) The laminated body which laminates | stacks a cover film on the layer which consists of an uncured photocurable resin composition in the laminated body in any one of said (a)-(g). Can also be used. In the method for producing a film-shaped optical waveguide of the present invention, as described above, it is preferable that at least the intermediate cladding layer 36 is formed using a dry film. The intermediate clad layer can be formed using the laminate of the above (c), but is preferably formed using the laminate of the above (g).

[Manufacturing Method of Film Optical Waveguide] The manufacturing method of the film optical waveguide 1 includes a step of preparing a dry film 30 for forming the intermediate cladding layer 36 and the upper cladding layer 33, a step of forming the lower cladding layer 15, The step of forming the core portion 22 and the step of forming the intermediate cladding layer 36 and the upper cladding layer 33 using the dry film 30 are included. In addition, the composition for forming each part of the lower clad layer 15, the core portion 22, the intermediate clad layer 36, and the upper clad layer 33 constituting the film-shaped optical waveguide is respectively a lower layer composition and a core composition for convenience. These are referred to as the composition, the intermediate layer composition, and the upper layer composition.

(1) Preparation of material Each component composition of the lower layer composition, the core composition, the intermediate layer composition, and the upper layer composition is composed of the lower cladding layer 15, the core portion 22, the intermediate cladding layer 36, and the upper layer. The relationship of the refractive index of each part of the clad layer 33 is determined so as to satisfy the conditions required for the film-like optical waveguide. Specifically, three or four types of photocurable compositions are prepared so that the difference in refractive index is an appropriate magnitude, and among these, the photocurable composition that gives the cured film with the highest refractive index is the core. The other photocurable composition is used as the lower layer composition, the intermediate layer composition, and the upper layer composition. The lower layer composition and the upper layer composition are preferably the same photocurable composition (the above-described photocurable resin composition for the clad layer) in terms of economy and production management.

(2) Step of preparing a dry film for forming an intermediate cladding layer and an upper cladding layer From a base film 31, an upper cladding layer 33 (a layer made of a cured product of an upper layer composition), and an uncured intermediate layer composition This is a step of preparing a dry film 30 that is a laminate with the layer 34. As base film 31, what has flexibility and has high permeability to light used for hardening of a photocurable resin composition is preferred. Examples of such a base film include a polyethylene terephthalate film and a polyethylene naphthalate film. Although the thickness of a base film is not specifically limited, For example, it is 10-200 micrometers. By using such a base film, the layer 34 made of the uncured intermediate layer composition can be cured by irradiating light from the base film 31 side in the step (5) described later. Moreover, the base film 31 can be used as the support film 3 of a film-like optical waveguide as it is. In addition, in the dry film 30, the cover film 35 can be provided in the upper surface of the layer 34 which consists of a composition for middle layers as needed. Examples of the cover film include a polyethylene film, a polypropylene film, and a polyethylene terephthalate film. Although the thickness of a cover film is not specifically limited, For example, it is 5-100 micrometers.

The dry film 30 is obtained as follows, for example. First, the upper layer composition is applied to the upper surface of the base film 31, and dried or prebaked as necessary to form the upper layer thin film 32 ((a) in FIG. 3). Next, the upper thin film 32 is irradiated with light and cured to form an upper clad layer 33 which is a cured body ((b) in FIG. 3). Next, the intermediate layer composition is applied to the upper surface of the upper clad layer 33, and dried or prebaked to disperse the solvent, thereby forming a layer 34 of the uncured intermediate layer composition (in FIG. 3). (C)). As needed, the dry film 30 is obtained by providing the cover film 35 on the upper surface of the layer 34 which consists of a composition for uncured middle layers ((d) in FIG. 3). Examples of the method for applying the photocurable resin composition (upper layer composition, middle layer composition) include spin coating, dipping, spraying, bar coating, roll coating, curtain coating, gravure printing, Examples thereof include a silk screen method and an ink jet method.

The temperature at the time of drying or prebaking the composition for upper layers is 50-200 degreeC, for example. The amount of light irradiation when forming the upper cladding layer 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 in an amount of 10 to 5,000 mJ / cm 2. 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, and γ rays 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. In forming the upper clad layer, it is preferable to irradiate the entire surface of the upper layer thin film 32 with light to cure the whole. Further, after the exposure, it is preferable to perform a heat treatment (post-bake) so that the entire surface of the upper clad layer 33 is sufficiently cured. This heating condition varies depending on the blending composition of the photocurable resin composition, the kind of additive, and the like, but usually the heating temperature is 30 to 300 ° C, preferably 50 to 200 ° C, and the heating time is 5 minutes to 72. It's time.

The intermediate layer composition is dried or prebaked for the purpose of scattering the organic solvent. The temperature condition at this time is preferably 30 to 150 ° C, more preferably 50 to 140 ° C. In the layer 34 composed of the composition for the middle layer, the amount of the organic solvent remaining after drying is preferably 20% by mass or less based on 100% by mass of the photocurable resin composition after the organic solvent is dispersed. The thickness of the layer 34 made of the uncured intermediate layer composition is usually 1 to 200 μm. In addition, it is preferable that the thickness of the layer 34 which consists of a composition for uncured intermediate | middle layers is 1-1.2 times with respect to the height of the core part 22. FIG. By setting the thickness of the layer 34 made of the uncured intermediate layer composition to 1 to 1.2 times the height of the core portion 22, the intermediate clad layer is formed using the dry film 30 in the step (5) described later. The workability at the time of forming 36 can be improved, and the shape accuracy and transmission characteristics of the finally obtained film-like optical waveguide can be improved.

(3) Forming process of lower clad layer In this process, the lower clad layer 15 is formed on the upper surface of the support film 2. Specifically, the lower layer composition is applied to the surface of the support film 2, and dried or prebaked as necessary to form the lower layer thin film 14 ((a) in FIG. 4). Next, the lower layer thin film 14 is irradiated with light and cured to form a lower cladding layer 15 which is a cured body ((b) in FIG. 4). In forming the lower cladding layer 15, it is preferable to irradiate the entire surface of the thin film with light and harden the whole. Moreover, it is preferable to further heat-treat (post-bake) so that the whole coating film may fully harden | cure after exposure. As the support film 2, a film having flexibility and high transparency to the light used for curing the photocurable resin composition is preferable. Examples of such a support film include polyethylene terephthalate film and polyethylene naphthalate. Although the thickness of a support film is not specifically limited, For example, it is 10-200 micrometers. In the lower clad layer forming step, the composition coating method, light irradiation amount, type, light (ultraviolet) irradiation device, pre-bake and post-bake conditions, etc. The conditions are the same as the formation conditions. The lower clad layer 15 can also be formed using a dry film. In this case, an uncured lower layer was prepared using a dry film 10 (a dry film that is a laminate of a base film 11 and an uncured lower layer composition 13; see FIG. 2B). The lower clad layer 15 is formed by irradiating and curing the layer 13 made of the composition for use. The base film 11 can be used as the support film 2 of a film-like optical waveguide as it is. For example, the dry film 10 is formed by applying the lower layer composition 12 on the upper surface of the base film 11 ((a) in FIG. 2), and drying or prebaking to disperse the organic solvent, thereby uncured lower layer composition. It is obtained by forming a layer 13 made of ((b) in FIG. 2). In the dry film 10, a cover film can be provided on the upper surface of the layer 13 made of the uncured lower layer composition (not shown in the drawing) as necessary. And the same as the base film and cover film in the dry film 30). The application method of the lower layer composition, the conditions for drying or pre-baking, and the like are the same as the conditions for the intermediate layer composition in step (2) above. The layer 13 composed of the uncured lower layer composition can be subjected to drying or pre-baking, post-baking after exposure, and the like as required, similarly to the lower layer thin film 14.

(4) Core Part Formation Step This is a step of forming the core part 22 on the surface of the lower cladding layer 15. Specifically, as shown in FIG. 4C, a core composition is applied to the surface of the lower cladding layer 15, and dried or prebaked as necessary to form the core thin film 21. Thereafter, as shown in FIG. 4D, irradiation (exposure) of light 5 is performed on the upper surface of the core thin film 21 according to a predetermined pattern, for example, through a photomask 4 having a predetermined line pattern. Do. As a result, only the portion irradiated with light in the core thin film 21 is cured, so that other uncured portions are developed and removed, as shown in FIG. On the lower cladding layer 15, a core portion 22 made of a patterned cured film is formed.

In this step, the method of irradiating light according to a predetermined pattern is not limited to the method using the photomask 4 composed of the light transmitting portion and the non-transmitting portion. For example, any of the following methods a to c 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 photosensitive resin composition while scanning a laser beam or convergent light obtained by a condensing optical system such as a lens or a mirror.

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. As the developer, an ordinary organic solvent used in the development process or a dilute alkaline aqueous solution can be used. When the above-mentioned core-forming photocurable resin composition is used as the core composition, it can be developed with a dilute alkaline aqueous solution excellent in environmental safety. Examples of alkali compounds for preparing dilute aqueous alkali solutions include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propyl. Amine, triethylamine, methyldiethylamine, N-methylpyrrolidone, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, 1,8-diazabicyclo [5.4.0]- Examples include 7-undecene and 1,5-diazabicyclo [4.3.0] -5-nonane. Of these, tetramethylammonium hydroxide (TMAH), potassium hydroxide, and the like are preferably used. The concentration of the alkali compound in the aqueous alkali solution varies depending on the type of the alkali compound used, but in the case of an organic alkali, it is preferably 0.05 to 10% by mass, more preferably 0.1 to 7% by mass. . For example, when tetramethylammonium hydroxide (TMAH) is used, the concentration is preferably 0.5 to 2.5% by mass. In addition, it is also preferable to add an appropriate amount of a water-soluble organic solvent such as methanol or ethanol, a surfactant or the like to such a dilute alkaline aqueous solution and use it as a developer.

The developing time is usually 30 to 600 seconds, and a known method such as a liquid piling method, a dipping method, or a shower developing method can be adopted as the developing method. Thereafter, washing with running water is performed for 30 to 90 seconds, for example, and the moisture on the surface is removed by air drying with compressed air, compressed nitrogen, or the like, thereby forming a patterned cured body. Next, a sufficiently hardened core portion 22 can be formed by post-baking for 5 to 600 minutes at a temperature of 30 to 300 ° C. with a heating device such as a hot plate or an oven. The conditions of the composition coating method, light irradiation amount, type, light (ultraviolet) irradiation device, etc. in the core portion forming step are the same as the conditions for forming the upper clad layer in the above step (2). .

The core portion 22 can be formed using a dry film. In this case, a dry film (a dry film including a base film, a layer made of an uncured core composition, and a cover film as necessary) prepared in advance is used, and the cover film is formed on the upper surface of the lower clad layer 15. The dry film having been peeled off is laminated so that the layers made of the uncured core composition face each other. Next, the layer made of the core composition is irradiated with light according to a predetermined pattern, and the uncured portion is developed and removed, whereby a patterned cured film is formed on the lower cladding layer 15. A core portion 22 is formed. As a base film and a cover film, the thing similar to the base film in the dry film 30 of the above-mentioned process (2) and a cover film is mentioned. The layer made of the uncured core composition can be subjected to drying or pre-baking, post-baking after exposure, and the like as required, as with the core thin film 21.

(5) Step of forming intermediate clad layer and upper clad layer Dry film 30 (base film 31, upper clad layer 33, layer 34 made of uncured intermediate layer composition) prepared in step (2) above The intermediate clad layer 36 and the upper clad layer 33 are formed using the above laminate. Specifically, the dry film 30 is laminated on the upper surfaces of the lower clad layer 15 and the core portion 22 so that the layer 34 made of the uncured intermediate layer composition faces ((f) in FIG. 4). Then, the core portion 22 and the upper clad layer 33 are bonded together so as to come into contact ((g) in FIG. 4). Next, the layer 34 made of the intermediate layer composition is cured by irradiating light to form an intermediate cladding layer 36 ((h) in FIG. 4), whereby the film-shaped optical waveguide 1 is obtained. When the dry film 30 has the cover film 35, the cover film 35 is peeled off, and then the dry film 30 is laminated on the upper surfaces of the lower cladding layer 15 and the core portion 22. Moreover, the base film 31 can be used as the support film 3 of the film-form optical waveguide 1 without peeling off as it is.

When the dry film 30 is laminated and bonded to the upper surfaces of the lower cladding layer 15 and the core portion 22, the layer 34 made of the uncured intermediate layer composition may protrude from the lower cladding layer 15. This protruding portion is removed. In the formation of the intermediate cladding layer 36, the light irradiation amount, type, light (ultraviolet) irradiation device, pre-bake and post-bake conditions, and the like are the same as those for the formation of the upper clad layer in the above step (2). is there. By laminating and laminating the dry film 30 as described above, the layer 34 made of the uncured intermediate layer composition has the core portion 22 that is a cured body as a spacer, and the lower clad layer 15 and the upper clad layer. 33. In this state, the intermediate clad layer 36 having a uniform thickness can be formed by curing the layer 34 made of the intermediate layer composition by light irradiation. As a result, the thickness of the cladding layers around the core portion 22 (the lower cladding layer 15, the intermediate cladding layer 36, and the upper cladding layer 33) can be made uniform, so that the optical characteristics of light propagating through the core portion 22 are good. Can be realized. The film-shaped optical waveguide can also be used with the support films 2 and 3 peeled off.

Hereinafter, the present invention will be specifically described by way of examples.
[1. Preparation of each component of photocurable resin composition]
The following materials were prepared as urethane (meth) acrylate oligomers, reactive diluent monomers, photopolymerization initiators, organic solvents, vinyl polymers having an ethylenically unsaturated group, and other additives.
[Urethane (meth) acrylate oligomer; component (A) of photocurable resin composition for clad layer, component (a) of photocurable resin composition for intermediate layer, component of photocurable resin composition for core (b) ]]
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, and A-1 was obtained.
A-2 to A-9 were obtained in the same manner.
Table 1 shows the raw material names and amounts used for the production of A-1 to A-9.

[Reactive dilution monomer; component (B) of photocurable resin composition for clad layer, component (b) of photocurable resin composition for intermediate layer, component (c) of photocurable resin composition for core] (1) N-vinyl-2-pyrrolidone; manufactured by ISP, V-PYROL (2) N-vinylcaprolactam; manufactured by ISP, V-CAP (3) isobornyl acrylate; manufactured by Osaka Organic Chemical Industry, IBXA ( 4) Bisphenol A EO adduct diacrylate; manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat 700 (5) 2,2-bis-4 (2-hydroxy-3-acryloxypropylphenyl) propane; manufactured by Showa Polymer Co., Ltd., VR -77 (6) 1,9-nonanediol diacrylate; manufactured by Osaka Organic Chemical Industry Co., Ltd., Viscoat 260 (7) 9,9-bis [4- (2-acryloxyethoxy) phenyl] full Len; Shin-Nakamura Chemical Co., Ltd., NK ester A-BPEF (8) 1,6-hexanediol diacrylate; Kyoeisha Chemical Co., Ltd., light acrylate 1,6-HX-A (9) EO-modified trimethylolpropane triacrylate Manufactured by Osaka Organic Chemical Industry Co., Ltd., Biscoat 360 (10) Tris (acryloxy) isocyanurate; manufactured by Toagosei Co., Ltd., Aronics M-315 (11) dipentaerythritol hexaacrylate; manufactured by Nippon Kayaku Co., Ltd., KAYARAD DPHA [polymerization initiator The component (C) of the photocurable resin composition for the cladding layer, the component (c) of the photocurable resin composition for the intermediate layer, the component (d) of the photocurable resin composition for the core] (1) Irgacure 369; 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, Ciba Specialty Chemicals (2) Irgacure 184; 1-hydroxycyclohexyl phenyl ketone, Ciba Specialty Chemicals [organic solvent; photocurable resin composition for clad layer (D), intermediate layer photocurable resin Component (d) of composition, component (e) of photocurable resin composition for core] (1) Methoxypropyl acetate

[Vinyl polymer having an ethylenically unsaturated group; component (E) of photocurable resin composition for clad layer, component (e) of photocurable resin composition for intermediate layer, photocurable resin composition for core Ingredients (I)]
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 carried out 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 A flask equipped with a dry ice / methanol reflux was purged with nitrogen, and then 3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 100 g of methyl isobutyl ketone as an organic solvent were added. Stir until dissolved. 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, 3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 100 g of methyl isobutyl ketone as an organic solvent were added. Stir until dissolved. Subsequently, 20 g of 2-hydroxyethyl methacrylate, 10 g of methacrylic acid, 20 g of styrene, 40 g of 4- (1-methyl-1-phenylethyl) phenoxyethyl acrylate, and 10 g of n-butyl acrylate were added, and then gently stirred. It was. 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 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 to E-3.

In the blending ratio shown in Table 3, the above-mentioned components are uniformly mixed, and photocurable resin compositions J-1 to J-13 for the lower clad layer, upper clad layer, and intermediate clad layer, and photocured for the core. Resin compositions K-1 to K-2 were obtained.

[2. Formation of Film Optical Waveguide] [Example 1] (1) Preparation of Dry Film for Forming Intermediate Cladding Layer and Upper Cladding Layer First, a photocurable resin composition J-1 is made of polyethylene terephthalate (PET) base film. A coating film made of the photocurable resin composition J-1 was formed on the upper surface of the film by a spin coater. Next, the coating film was irradiated with ultraviolet rays having a wavelength of 365 nm and an illuminance of 20 mW / cm ² for 100 seconds to be photocured to form an upper cladding layer having a thickness of 10 μm. Subsequently, after the photocurable resin composition J-11 is applied to the upper surface of the upper clad layer with a spin coater, it is pre-baked using a hot plate at 100 ° C. for 10 minutes to obtain an uncured photocurable resin composition. By forming a layer made of the product J-11, it consists of a base film, an upper clad layer (a cured product of the photocurable resin composition J-1), and an uncured photocurable resin composition J-11. A dry film obtained by laminating layers was obtained. (2) Formation of lower clad layer First, the photocurable resin composition J-1 was applied to the upper surface of a polyethylene terephthalate (PET) support film (thickness: 100 μm) with a spin coater, and the photocurable resin composition J A coating consisting of -1 was formed. Next, the coating film was irradiated with ultraviolet rays having a wavelength of 365 nm and an illuminance of 20 mW / cm ² for 100 seconds to be photocured to form a lower cladding layer having a thickness of 10 μm. (3) Formation of core part Next, the photocurable resin composition K-2 for the core is applied onto the lower clad layer with a spin coater, and prebaked at 100 ° C. for 10 minutes to form a coating film. did. Subsequently, the coating film was irradiated with ultraviolet rays having a wavelength of 365 nm and an illuminance of 20 mW / cm ² for 75 seconds through a photomask having a line pattern having a width of 50 μm to be 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. Then, the core part (thickness 50 micrometers) which has a line-shaped pattern 50 micrometers in width was formed by postbaking on 150 degreeC and the conditions for 1 hour. (4) Formation of Intermediate Cladding Layer and Upper Cladding Layer Subsequently, the dry film is laminated on the upper surfaces of the lower cladding layer and the core portion so that the layer made of the uncured photocurable resin composition J-11 faces each other. Then, the core portion and the upper clad layer in the dry film were bonded together. Thereafter, the layer made of the uncured photocurable resin composition J-11 is cured by irradiating with an ultraviolet ray having a wavelength of 365 nm and an illuminance of 20 mW / cm ² for 100 seconds to form an intermediate cladding layer having a thickness of 50 μm. A laminate comprising a support film, a lower clad layer, a core portion, an intermediate clad layer, an upper clad layer, and a support film was obtained. (5) Peeling of the substrate The cured product formed in the steps (1) to (4) above is peeled off from the support film, and the lower cladding layer, the core portion, the intermediate cladding, and the upper cladding layer are laminated in this order. A film-like optical waveguide was obtained.

[Examples 2 to 8, Comparative Examples 1 to 4] A photocurable resin composition for forming a clad layer (a lower clad layer, an upper clad layer, and an intermediate clad layer) and light for forming a core portion A film-shaped optical waveguide was formed in the same manner as in Example 1 except that the curable resin composition was changed as shown in Table 4.

[Evaluation of Film Optical Waveguide] Film optical waveguides (Examples 1 to 8 and Comparative Examples 1 to 4) 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 test 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 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. Measure the number of times until the film-shaped optical waveguide breaks, “○” if no break or crack occurs even if the number of bending exceeds 100,000, and break or crack occurs when the number of bending is less than 100,000 The case where it does is made "x". [2. Waveguide loss] With respect to the produced film-shaped optical waveguide, light having a wavelength of 850 nm was incident from one end. Then, by measuring the amount of light emitted from the other end, the waveguide loss per unit length was determined by the cutback method. A case where the waveguide loss was 0.5 dB / cm or less was rated as “◯”, and a case where the waveguide loss exceeded 0.5 dB / cm was rated as “x”. The results are shown in Table 4.

Table 4 shows that the film-form optical waveguide (Examples 1-8) of this invention is excellent in bending durability. On the other hand, in the comparative example 1 which used the photocurable resin composition which does not contain a urethane (meth) acrylate oligomer as a material of a lower clad layer, an upper clad layer, and an intermediate | middle clad layer, it turns out that bending durability is inferior. Further, a photocurable resin composition in which the blending amount of any one or both of the urethane (meth) acrylate oligomer and the reactive dilution monomer is outside the scope of the present invention is applied to the lower cladding layer, the upper cladding layer, and the intermediate cladding layer. In Comparative Examples 2 to 4 used as the material, it can be seen that the bending durability is inferior.

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 dry film for lower clad layer formation. It is a flowchart which shows an example of the manufacturing method of the dry film for intermediate | middle clad layers and upper clad layers formation. 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 1 Film-form optical waveguide 2 Support film 3 Support film 4 Photomask 5 Light 10 Dry film for lower clad layer formation 11 Base film 12 Lower layer composition 13 Layer which consists of uncured lower layer composition 14 Lower layer thin film 15 Lower Cladding layer 21 Thin film for core 22 Core portion 30 Dry film for forming intermediate clad layer and upper clad layer 31 Base film 32 Thin film for upper layer 33 Upper clad layer 34 Layer made of uncured intermediate layer composition 35 Cover film 36 Middle Cladding layer

Claims (2)

A film-shaped optical waveguide including a lower cladding layer, a core portion, an intermediate cladding layer, and an upper cladding layer,
The lower clad layer and the upper clad layer are urethane (A) (A-1) reaction product of (A-1) polyol compound, (A-2) polyisocyanate compound, and (A-3) hydroxyl group-containing (meth) acrylate. 30 to 80% by mass of urethane (meth) acrylate oligomer containing a meth) acrylate oligomer in the total amount of component (A) at a blending ratio of 50% by mass or more , (B) 15 to 69% by mass of reactive dilution monomer , and (C Cladding layer containing 0.1) -10% by weight of a photopolymerization initiator and not containing (E) a vinyl polymer having an ethylenically unsaturated group, or containing 10% by weight or less. Photocurable resin composition (however, each compounding ratio of components (A) to (C) and (E) is 100% by mass of the total solid content of the photocurable resin composition for cladding layers) Is a value if.) Consists of a cured product,
The intermediate clad layer comprises: (a) urethane (meth) acrylate oligomer 5 to 80% by mass, (b) reactive dilution monomer 1 to 40% by mass, (c) photopolymerization initiator 0.1 to 10% by mass, and (E) A photocurable resin composition for an intermediate layer containing 15 to 75% by mass of a vinyl polymer having an ethylenically unsaturated group (however, the blending ratio of each of the components (a) to (c) and (e) is A film-shaped optical waveguide comprising a cured product of a solid content of the photocurable resin composition for intermediate layer of 100% by mass) . (A-1) The film-form optical waveguide according to claim 1 , wherein the polyol compound is at least one selected from the group consisting of aliphatic polyether polyols, aromatic polyether polyols, polyester polyols, and polycarbonate polyols.

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