JP4682955B2 - Manufacturing method of optical waveguide - Google Patents

Description

  The present invention relates to an optical waveguide manufacturing method, and more particularly to an optical waveguide manufacturing method including a step of forming a core portion by irradiating a photosensitive composition with light.

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 such an optical waveguide is a quartz-based waveguide. However, a special manufacturing apparatus is required and a long manufacturing time is observed.

In order to solve these problems, various methods for producing an optical waveguide using a dry film in which an uncured photosensitive resin composition layer is formed on a base film have been proposed.
For example, (A) a carboxyl group-containing urethane compound, (B) a polymerizable unsaturated compound, (C) two or more ring-opening polymerizable functional group-containing compounds in the molecule, and (D) a radiation polymerization initiator are essential. A dry film for forming an optical waveguide comprising a photosensitive resin composition contained as a component, wherein the dry film has a softening temperature of 0 ° C. to 80 ° C. (Patent Document 1).
Further, (A) a copolymer obtained from a radically polymerizable compound having a carboxyl group and other radically polymerizable compounds and having a glass transition temperature of 20 ° C. or higher and 150 ° C. or lower, (B) two in the molecule There has been proposed a radiation-curable dry film for forming an optical waveguide characterized by containing the above compound having a polymerizable reactive group and (C) a radiation polymerization initiator (Patent Document 2).
Furthermore, (A) a vinyl polymer having a carboxyl group, a polymerizable group and other organic groups, (B) a compound having two or more polymerizable reactive groups in the molecule, and (C) radiation polymerization initiation A radiation-curable dry film for forming an optical waveguide characterized by containing an agent component has been proposed (Patent Document 3).
JP 2005-208563 A JP 2003-202437 A JP 2003-195080 A

According to the technique of each of the above-mentioned documents (Patent Documents 1 to 3), it is advantageous in that an optical waveguide can be manufactured in a short time and at a low cost as compared with a conventional method for manufacturing a silica-based optical waveguide.
However, the present inventor has found that there is the following problem when forming the core portion of the optical waveguide using a dry film.
That is, to form the core portion of the optical waveguide using a dry film, after laminating (transferring) the dry film on the lower cladding layer so that the base film is on the upper side, the base film is peeled off, The exposed photosensitive composition layer may be irradiated with light such as ultraviolet rays through a photomask composed of a light transmitting portion and a non-transmitting portion to cure the photosensitive composition layer. It is done. In addition, when light is irradiated while the base film is left in place, the light transmittance is deteriorated by the base film, which adversely affects the progress of partial curing of the photosensitive composition layer.
However, since the photosensitive composition layer containing a specific monomer such as a monomer having a (meth) acryloyl group has adhesiveness (tack), a photomask is attached after peeling the base film. It was necessary to pay close attention to prevent this from happening, and it was found that there were problems such as poor workability.
The present invention is intended to solve the above-described problems, and an optical waveguide capable of forming an optical waveguide with high shape accuracy and good transmission characteristics (waveguide loss) with a simple manufacturing process with high work efficiency. An object is to provide a method for manufacturing a waveguide.

As a result of diligent studies to solve the above problems, the present inventor has applied (i) a photosensitive composition for forming a core portion on the lower cladding layer to form a photosensitive composition layer. Then, a specific film is laminated on the photosensitive composition layer, and (ii) the photosensitive film layer in the state where the film of (i) is in contact with the photosensitive composition layer. According to a method including irradiating light to the composition layer, etc., an optical waveguide having high shape accuracy and good transmission characteristics (waveguide loss) can be formed with a simple manufacturing process with high work efficiency. The present invention has been completed.
That is, the present invention provides the following [1] to [ 4 ].
[1] A method for producing an optical waveguide including a lower cladding layer, a core portion, and an upper cladding layer, the photosensitive composition for forming a core portion on a lower cladding layer formed on a substrate Film lamination step of laminating a film made of a synthetic resin containing a filler having a number average particle size of 5 to 100 nm on the photosensitive composition layer And in a state where the film is in contact with the photosensitive composition layer, the photosensitive composition layer is irradiated with light through the film, and the photosensitive composition of the photosensitive composition layer is partially A core pattern forming step of forming a core pattern-containing layer comprising a cured portion and an uncured portion; and, after peeling the film, developing the core pattern-containing layer, thereby lowering the lower cladding layer and the core portion. A method of manufacturing an optical waveguide, comprising: a core part forming step for obtaining a laminated body including an upper clad layer forming step for forming an upper clad layer on the lower clad layer and the core part.
[ 2 ] The method for producing an optical waveguide according to [1] , wherein the film has a surface roughness (Ra) of 30 nm or less.
[ 3 ] The method for producing an optical waveguide according to [1] or [2] , wherein the film has a thickness of 300 μm or less.
[ 4 ] The method for producing an optical waveguide according to any one of [1] to [ 3 ], wherein the photosensitive composition contains a monomer having a (meth) acryloyl group and a photoradical polymerization initiator.

According to the method for manufacturing an optical waveguide of the present invention, since a specific film is used, the surface of the core portion is uneven due to light scattering on the surface or inside of the base film by a filler having a large particle size. There will be no problems. For this reason, although the photosensitive composition layer located under the film is cured by irradiating light from above the film, a core portion having a high shape accuracy can be formed.
Further, according to the method for producing an optical waveguide of the present invention, light is passed through the film from above with respect to the photosensitive composition layer positioned below the film while the film is in contact with the photosensitive composition layer. Since irradiation is performed, inhibition of polymerization due to oxygen in radical polymerization during curing of the photosensitive composition layer can be prevented, and a core portion excellent in dimensional stability can be formed.
Furthermore, according to the method for manufacturing an optical waveguide of the present invention, the optical waveguide can be manufactured with a simple manufacturing process with high work efficiency.

An optical waveguide manufacturing method of the present invention is an optical waveguide manufacturing method including a lower clad layer, a core portion, and an upper clad layer, wherein the core portion is formed on the lower clad layer formed on the substrate. After forming a photosensitive composition layer by applying a photosensitive composition for forming, a synthetic resin containing a filler having a number average particle diameter of 5 to 100 nm is formed on the photosensitive composition layer. A film laminating step for laminating a film, and in a state where the film is brought into contact with the photosensitive composition layer, the photosensitive composition layer is irradiated with light (for example, ultraviolet rays) through the film, thereby the photosensitivity. A core pattern forming step of partially curing the photosensitive composition of the composition layer to form a core pattern-containing layer composed of a cured portion and an uncured portion, and after peeling the film, the core pattern-containing layer is Develop It allows those comprising a core portion forming step of obtaining a laminate including a lower cladding layer and the core portion, and an upper clad layer forming step of forming an upper cladding layer on the lower clad layer and the core portion of the above.

Examples of the base material used in the present invention include a substrate made of an inorganic material such as a silicon substrate and a glass substrate, and a synthetic resin film or sheet made of the same material as a base film described later.
As an embodiment of a film lamination process, the following two examples are mentioned, for example.
The first embodiment of the film laminating step is a method for forming a core part-forming dry film having a film and a photosensitive composition layer formed on the film, and forming the surface on the photosensitive composition layer side as a lower cladding. It is laminated on the layer. In addition, the film in this form example is also called a base film.
In the second embodiment of the film lamination step, a photosensitive composition layer is formed by applying a photosensitive composition for forming a core part on the lower clad layer, and then forming the photosensitive composition layer. A film is laminated thereon.

As a film used at a film lamination process, what contains the filler whose number average particle diameter is 5-100 nm in the matrix (base material) which consists of synthetic resins, such as polyethylene terephthalate polyethylene, a polypropylene, and polyester, is mentioned.
Here, “the particle size of the filler” means that measured by a transmission electron microscope.
Examples of the filler include particles such as silica, calcium carbonate, magnesium carbonate, polystyrene, carbon-silica dual phase filler, clay, and carbon black.
Among them, particles such as silica, calcium carbonate, magnesium carbonate, and polystyrene do not greatly reduce the light transmittance in the film when the photosensitive composition layer located below the film is cured by light irradiation. Therefore, it is preferable.
The number average particle diameter of the filler is 5 to 100 nm, preferably 5 to 50 nm, and more preferably 5 to 30 nm. When the number average particle diameter exceeds 100 nm, the accuracy of the shape of the core portion may be lowered.
In the present specification, “a filler having a number average particle diameter of 5 to 100 nm” means that when a plurality of types of fillers are included, the total number average particle diameter of these plurality of types of fillers is 5 to 100 nm. It means that. Therefore, a specific type of filler having a number average particle diameter of 5 to 100 nm and another specific type of filler having a number average particle exceeding 100 nm are used in combination, and the whole number average particle of these two types of fillers. When a diameter exceeds 100 nm, it does not correspond to the filler used by this invention.

The mass ratio of the filler in the film is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less. If the mass ratio exceeds 5%, the accuracy of the shape of the core portion may be reduced, or the light transmittance may be reduced, and the working efficiency for forming the core portion may be reduced.
Although the lower limit of the mass ratio of the filler in a film is not specifically limited, Preferably it is 0.001% or more. If the mass ratio is less than 0.001%, there is a drawback that it is difficult to handle a long film.
The surface roughness (Ra) of the film containing the filler is preferably 30 nm or less, more preferably 20 nm or less, still more preferably 15 nm or less, and particularly preferably 10 nm or less. When the surface roughness (Ra) exceeds 30 nm, the accuracy of the shape of the core portion may be lowered.
The surface roughness (Ra) is a center line average roughness (Ra) measured by a method according to “JIS B0601”. The method for measuring the surface roughness is not particularly limited, and examples thereof include a method of observing a cross section of the film with an electron microscope, a stylus type surface roughness meter, and a method of observing with an atomic force microscope.
The thickness of the film is preferably 300 μm or less, more preferably 200 μm or less, still more preferably 5 to 200 μm, and particularly preferably 10 to 150 μm. When the thickness exceeds 300 μm, the light transmittance is reduced, the accuracy of the shape of the core part may be lowered, and the working efficiency for forming the core part may be lowered.

［式中、Ｒ^１、Ｒ^２、Ｒ^３は各々独立して水素原子または炭素数１〜１２のアルキル基、Ｘはカルボキシル基を有する基、Ｙは反応性官能基を有する基、ＺはＸおよびＹ以外の有機基であり、ｌ、ｎ、ｍは各々、０ではない繰り返し単位数を示す。］、（Ｂ）ポリエステルポリオール化合物と、ポリイソシアネート化合物と、水酸基含有（メタ）アクリレートとの反応生成物であるウレタン（メタ）アクリレート化合物、（Ｃ）分子内に１個以上のエチレン性不飽和基を有し、０．１ＭＰａにおける沸点が１３０℃以上である上記（Ａ）、（Ｂ）以外の化合物、並びに、（Ｄ）光ラジカル重合開始剤を含有する感光性樹脂組成物が挙げられる。 Examples of the photosensitive composition which is a material of the photosensitive composition layer for forming the core portion include a photosensitive resin composition containing a monomer having a (meth) acryloyl group and a radical photopolymerization initiator Is mentioned. The material of the cladding layer can also be composed of the same components as the material of the core part (however, the blending ratio is different).
As a suitable example of this photosensitive resin composition, the following (A) to (D):
(A) a copolymer having a structure represented by the following general formula (1):

[Wherein R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, X is a group having a carboxyl group, Y is a group having a reactive functional group, and Z is X And an organic group other than Y, and each of l, n, and m represents a number of repeating units other than 0. ] (B) Urethane (meth) acrylate compound which is a reaction product of a polyester polyol compound, a polyisocyanate compound, and a hydroxyl group-containing (meth) acrylate, (C) one or more ethylenically unsaturated groups in the molecule And a photosensitive resin composition containing a compound other than the above (A) and (B) having a boiling point of 130 ° C. or higher at 0.1 MPa, and (D) a photoradical polymerization initiator.

［Ｒ^１、Ｒ^２、Ｒ^３は各々独立して水素原子または炭素数１〜１２のアルキル基、Ｘはカルボキシル基を有する基、Ｙは反応性官能基を有する基、ＺはＸおよびＹ以外の有機基であり、ｌ、ｎ、ｍは各々、０ではない繰り返し単位数を示す。］ Hereinafter, said (A)-(D) component is explained in full detail.
[(A) component]
The component (A) used in the present invention is a copolymer having a structure represented by the following general formula (1).

[R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, X is a group having a carboxyl group, Y is a group having a reactive functional group, Z is other than X and Y And each of l, n, and m represents a number of repeating units that is not 0. ]

  (A) The weight average molecular weight of a component becomes like this. Preferably it is 5,000-100,000, More preferably, it is 8,000-70,000, Most preferably, it is 10,000-50,000. If the value is less than 5,000, the composition has a disadvantage that the viscosity of the composition becomes small and a desired film thickness cannot be obtained. If the value exceeds 100,000, the viscosity of the composition becomes large and the coating property becomes poor. Have disadvantages such as worsening.

The component (A) can be obtained by either of the following two methods (1) and (2). The compound (c) is a radical polymerizable compound other than the compounds (a) and (b).
(1) (a) a radically polymerizable compound having a carboxyl group, (b) a radically polymerizable compound having a reactive functional group (for example, a cyclic ether such as an epoxy group or an oxetanyl group), and (c) another radical polymerization. A radical copolymerization of a functional compound in a solvent.
(2) (a) A radical polymerizable compound having a carboxyl group, and (c) another radical polymerizable compound is radically copolymerized in a solvent to obtain a polymer, and then (d) a reactive functional group ( For example, a method of adding a radically polymerizable compound having an epoxy group) to a part of the carboxyl group of the side chain of the polymer.

The compounds (a) to (d) used in the above methods (1) and (2) will be described.
Examples of the compound (a) (radical polymerizable compound having a carboxyl group) include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid. Acid; Methacrylic acid derivatives having a carboxyl group and an ester bond such as 2-succinoloylethyl methacrylate, 2-malenoloylethyl methacrylate, 2-hexahydrophthaloylethyl methacrylate, and the like.
Among these, acrylic acid, methacrylic acid, and 2-hexahydrophthaloylethyl methacrylate are preferable, and acrylic acid and methacrylic acid are particularly preferable.
A compound (a) is used individually by 1 type or in combination of 2 or more types.
(A) The content rate of the compound (a) in a component becomes like this. Preferably it is 5-50 mass%, More preferably, it is 10-40 mass%. When the content is less than 5% by mass, the composition of the present invention is not easily dissolved when subjected to an alkali development treatment after being cured by light irradiation. For example, it was used as a core portion of an optical waveguide. In this case, the core shape as designed cannot be obtained, and sufficient transmission characteristics cannot be obtained. When the content exceeds 50% by mass, the shape as designed cannot be obtained.

Examples of the compound (b) (radical polymerizable compound having a reactive functional group) include glycidyl (meth) acrylate, α-ethylglycidyl (meth) acrylate, α-n-propylglycidyl (meth) acrylate, α-n. -Butyl glycidyl (meth) acrylate, 2-methyl glycidyl (meth) acrylate, 2-ethyl glycidyl (meth) acrylate, 2-propyl glycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4- (Meth) acrylic acid esters having an epoxy group such as epoxy heptyl (meth) acrylate, α-ethyl-6,7-epoxyheptyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate; Ethyl-2-oxetanyl) methyl (meth) Chryrate, (2-methyl-2-oxetanyl) methyl (meth) acrylate, 2- (2-ethyl-2-oxetanyl) ethyl (meth) acrylate, 2- (2-methyl-2-oxetanyl) ethyl (meth) acrylate , (Meth) acrylic acid esters having an oxetanyl group such as 3- (2-ethyl-2-oxetanyl) propyl (meth) acrylate and 3- (2-methyl-2-oxetanyl) propyl (meth) acrylate; Vinyl benzyl glycidyl ether, m-vinyl benzyl glycidyl ether, p-vinyl benzyl glycidyl ether, α-methyl-o-vinyl benzyl glycidyl ether, α-methyl-m-vinyl benzyl glycidyl ether, α-methyl-p-vinyl benzyl glycidyl Ether, 2,3-diglycidyl Ruoxymethylstyrene, 2,4-diglycidyloxymethylstyrene, 2,5-diglycidyloxymethylstyrene, 2,6-diglycidyloxymethylstyrene, 2,3,4-triglycidyloxymethylstyrene, 2,3 , 5-triglycidyloxymethylstyrene, 2,3,6-triglycidyloxymethylstyrene, 3,4,5-triglycidyloxymethylstyrene, 2,4,6-triglycidyloxymethylstyrene, etc. Examples thereof include styrenes.
Among these, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, p-vinylbenzyl glycidyl ether and the like are preferably used.

A compound (b) is used individually by 1 type or in combination of 2 or more types.
The content rate of the compound (b) in (A) component becomes like this. Preferably it is 5-50 mass%, More preferably, it is 7-40 mass%. If the content is less than 5% by mass, curing may be insufficient. When this content rate exceeds 50 mass%, a cure shrinkage rate may become large and workability may fall.

The compound (c) (other radical polymerizable compound) is mainly used for appropriately controlling the mechanical properties and refractive index of the component (A).
Examples of the compound (c) include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, and t-butyl (meth) acrylate. (Meth) acrylic acid alkyl esters such as phenyl (meth) acrylate, benzyl (meth) acrylate and other (meth) acrylic acid aryl esters; dicyclopentanyl acrylate; diethyl maleate, diethyl fumarate, diethyl itaconate Dicarboxylic acid diesters such as; aromatic vinyls such as styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-methoxystyrene; 1,3-butadiene, isoprene, 1,4- Dimethyl butadiene Which conjugated diolefins; nitrile group-containing polymerizable compounds such as acrylonitrile and methacrylonitrile; chlorine-containing polymerizable compounds such as vinyl chloride and vinylidene chloride; amide bond-containing polymerizable compounds such as acrylamide and methacrylamide; vinyl acetate, etc. Examples include fatty acid vinyls.
Of these, methyl (meth) acrylate, n-butyl (meth) acrylate, styrene, α-methylstyrene and the like are preferably used.

A compound (c) is used individually by 1 type or in combination of 2 or more types.
The content rate of the compound (c) in (A) component becomes like this. Preferably it is 5-80 mass%, More preferably, it is 20-80 mass%. When the content is less than 5% by mass, it tends to be difficult to adjust the refractive index. If the content exceeds 80% by mass, curing tends to be insufficient.

Examples of the compound (d) (radical polymerizable compound having a reactive functional group) include glycidyl (meth) acrylate, α-ethylglycidyl (meth) acrylate, α-n-propylglycidyl (meth) acrylate, α-n. -Butyl glycidyl (meth) acrylate, 2-methyl glycidyl (meth) acrylate, 2-ethyl glycidyl (meth) acrylate, 2-propyl glycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4- (Meth) acrylic acid esters having an epoxy group such as epoxyheptyl (meth) acrylate, α-ethyl-6,7-epoxyheptyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate; o-vinyl Benzyl glycidyl ether, m-vinyl Benzyl glycidyl ether, p-vinylbenzyl glycidyl ether, α-methyl-o-vinylbenzyl glycidyl ether, α-methyl-m-vinylbenzyl glycidyl ether, α-methyl-p-vinylbenzyl glycidyl ether, 2,3-diglycidyl Oxymethylstyrene, 2,4-diglycidyloxymethylstyrene, 2,5-diglycidyloxymethylstyrene, 2,6-diglycidyloxymethylstyrene, 2,3,4-triglycidyloxymethylstyrene, 2,3, Styrene having an epoxy group such as 5-triglycidyloxymethylstyrene, 2,3,6-triglycidyloxymethylstyrene, 3,4,5-triglycidyloxymethylstyrene, 2,4,6-triglycidyloxymethylstyrene Such as The
Among these, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, p-vinylbenzyl glycidyl ether and the like are preferably used.
A compound (d) is used individually by 1 type or in combination of 2 or more types.
The content rate of the compound (d) in (A) component becomes like this. Preferably it is 5-50 mass%, More preferably, it is 7-40 mass%. When the content is less than 5% by mass, it is difficult to obtain sufficient curing. When this content rate exceeds 50 mass%, a cure shrinkage rate will become large and workability will fall.

Examples of the polymerization solvent used for radical copolymerization in the methods (1) and (2) include alcohols such as methanol, ethanol, ethylene glycol, diethylene glycol and 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, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. Alkyl ethers of alcohols; alkyl ether acetates of polyhydric alcohols such as ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate; aromatic hydrocarbons such as toluene and xylene; acetone, methyl ethyl ketone, methyl isobutyl Ketones such as ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol; ethyl acetate, butyl acetate, ethyl lactate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate Ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methyl Methyl Kishipuropion acid, 3-methoxy ethyl propionate, ethyl 3-ethoxypropionate, esters such as methyl 3-ethoxypropionate and the like.
Of these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones, and esters are preferred.

In addition, as a polymerization catalyst used for radical copolymerization, a normal radical polymerization initiator can be used, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvalero). Nitriles), 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile) and the like; benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1′-bis- (t There may be mentioned organic peroxides such as -butylperoxy) cyclohexane and hydrogen peroxide. When a peroxide is used as the radical polymerization initiator, a redox initiator may be used in combination with a reducing agent.
As the solvent used for the addition reaction in the method (2), the same solvent as the polymerization solvent used for radical copolymerization can be used. When performing the addition reaction, a thermal polymerization inhibitor can be added to suppress the polymerization reaction due to heat.
Examples of such thermal polymerization inhibitors include pyrogallol, benzoquinone, hydroquinone, methylene blue, tert-butylcatechol, monobenzyl ether, methoxyphenol, amylquinone, amyloxyhydroquinone, n-butylphenol, phenol and hydroquinone monopropyl ether. Can do.
The amount of the thermal polymerization inhibitor used is preferably 5 parts by mass or less with respect to 100 parts by mass of the component (A).

[Component (B)]
The component (B) is a urethane (meth) acrylate compound that is a reaction product of a polyester polyol compound, a polyisocyanate compound, and a hydroxyl group-containing (meth) acrylate.
As a manufacturing method of (B) component, the following manufacturing methods 1-4 are mentioned, for example.
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 is reacted again.
Among production methods 1 to 4, production methods 2 to 4 are preferable for controlling the molecular weight distribution.

(1) Polyol compound The polyol compound which is one of the raw materials of the component (B) of the present invention is a compound having two or more hydroxyl groups in the molecule. Examples of such compounds include aromatic polyether polyols, aliphatic polyether polyols, alicyclic polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, and the like.
Among these, in order to further improve the adhesiveness, it is preferable to use a polyether polyol compound containing an alkyleneoxy structure.
Aromatic polyether polyols 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, bisphenol F Propylene oxide addition diol, hydroquinone alkylene oxide addition diol, naphthoquinone alkylene oxide addition diol, and the like. As a commercial item, Uniol, DA700, DA1000 (above, Nippon Oil & Fats Corporation) etc. are mentioned, for example.
As the aliphatic polyether polyol, at least one compound selected from ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, substituted tetrahydrofuran, oxetane, substituted oxetane, tetrahydropyran and oxeban is used. Examples thereof include those obtained by ring-opening (co) polymerization. Specific examples 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, ethylene Copolymer polyol of oxide and tetrahydrofuran, copolymer polyol of ethylene oxide and propylene oxide, copolymer polyol of tetrahydrofuran and 3-methyltetrahydrofuran, copolymer polyol of ethylene oxide and 1,2-butylene oxide .

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.
Examples of commercially available 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, PTG3000, PTG650. , PTGL2000, PTGL1000 (above, manufactured by Hodogaya Chemical Co., Ltd.); EXENOL4020, EXENOL3020, EXENOL2020, (exceeded by Asahi Glass Co., Ltd.); 3201, 4200, 6300, 8200 (above, Sumika Bayer Urethane Co., Ltd.); NPML -2002, 3002, 4002, 8002 (above, manufactured by Asahi Glass Co., Ltd.).

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, 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, sebacin Examples thereof include polyester polyols obtained by reacting polybasic acids such as acids. As a commercial product, Kurapol P-2010, PMIPA, PKA-A, PKA-A2, PNA-2000, etc. (above, manufactured by Kuraray Co., Ltd.) are available.
Examples of the polycarbonate polyol include 1,6-hexane polycarbonate. Commercially available products include DN-980, 981, 982, 983 (above, manufactured by Nippon Polyurethane Co., Ltd.), PLACEL-CD205, CD-983, CD220 (above, manufactured by Daicel Chemical Industries), PC-8000 (produced by PPG, USA). Etc. are available.

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 commercially available products, PLACC CEL205, 205AL, 212, 212AL, 220, 220AL (manufactured by Daicel Chemical Industries, Ltd.) can be obtained.
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 the polyol compounds, polypropylene glycol, ethylene oxide / propylene oxide copolymer diol, ethylene oxide / 1,2-butylene oxide copolymer diol, and propylene oxide / tetrahydrofuran copolymer diol are preferable, and ethylene oxide / 1,2-butylene. An oxide copolymer diol is more preferred.

  The number average molecular weight of the polyol compound is preferably 400 to 10,000, more preferably 1,000 to 8,000, and most preferably 1,500 to 5,000. When the number average molecular weight is less than 400, the Young's modulus of the cured product at normal temperature and low temperature is increased, and it becomes difficult to obtain sufficient bending resistance. On the other hand, when the number average molecular weight exceeds 10,000, the viscosity of the composition increases and the coatability may deteriorate.

(2) Polyisocyanate compound The polyisocyanate compound which is one of the raw materials of the component (B) of the present invention is a compound having two or more isocyanate groups in the molecule. Examples of such compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, and 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, methylene bis (4-cyclohexyl isocyanate), 2,2,4-trimethylhexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, Diisocyanate compounds such as (2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, etc. Can be mentioned.
Of these, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and the like are preferable. These polyisocyanate compounds may be used alone or in combination of two or more.

(3) Hydroxyl group-containing (meth) acrylate The hydroxyl group-containing (meth) acrylate which is one of the raw materials of the component (B) of the present invention is a compound having a hydroxyl group and a (meth) acryloyl group in the molecule. Examples of such compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4 -Hydroxybutyl (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di ( And (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and the like. Furthermore, the compound obtained by addition reaction of a glycidyl group containing compound and (meth) acrylic acid, such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth) acrylate, is mentioned.
Of these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like are preferable.
The blending ratio of each raw material constituting the component (B) of the present invention is, for example, 0.5 to 2 mol of a polyol compound and 1 to 2.5 mol of a polyisocyanate compound with respect to 1 mol of a hydroxyl group-containing (meth) acrylate. is there.

The number average molecular weight (polystyrene conversion value measured by gel permeation chromatography) of the component (B) of the present invention is preferably 1,000 to 100,000, more preferably 3,000 to 60,000, particularly preferably. 5,000 to 30,000. When the number average molecular weight is less than 1,000, it is difficult to obtain sufficient bending resistance for the cured product (core portion) of the photosensitive resin composition layer when the optical waveguide is produced as a film. On the other hand, when the number average molecular weight exceeds 100,000, the viscosity of the composition becomes too high, and coatability may be deteriorated.
The amount of component (B) in the composition of the present invention is preferably 10 to 100 parts by weight, more preferably 20 to 80 parts by weight, and particularly preferably 35 to 70 parts by weight with respect to 100 parts by weight of component (A). Part by mass. When the amount is less than 10 parts by mass, sufficient bending resistance may not be obtained for the cured product (core portion) of the photosensitive resin composition layer when the optical waveguide is produced as a film. When the amount exceeds 100 parts by mass, the compatibility with the component (A) is deteriorated, and film roughness may occur on the surface of the cured product (core portion).

[Component (C)]
The component (C) is a compound other than the component (A) and the component (B) having at least one ethylenically unsaturated group in the molecule and having a boiling point at 0.1 MPa of 130 ° C. or higher.
Here, examples of the ethylenically unsaturated group include a (meth) acryloyl group and a vinyl group.
The molecular weight of the component (C) is preferably less than 2,000, more preferably less than 1,000.
Preferred examples of the component (C) having two or more ethylenically unsaturated groups in the molecule include two or more (meth) acryloyl groups and / or vinyl groups in the molecule, and a molecular weight of less than 1,000. The compound of this is mentioned.
In this case, all of the ethylenically unsaturated groups in the molecule may be any one of acryloyl group, methacryloyl group, and vinyl group, or acryloyl group and methacryloyl group, acryloyl group and vinyl group, and methacryloyl group. And a combination of any two of vinyl group, or a combination of three types of acryloyl group, methacryloyl group and vinyl group.

Examples of (meth) acrylates having two (meth) acryloyl groups in the molecule include 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, neopentyl glycol di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, bis (hydroxymethyl) ) Addition of tricyclodecane di (meth) acrylate, di (meth) acrylate of diol which is an adduct of bisphenol A ethylene oxide or propylene oxide, addition of ethylene oxide or propylene oxide of hydrogenated bisphenol A Di (meth) acrylate of diol, epoxy (meth) acrylate obtained by adding (meth) acrylate to diglycidyl ether of bisphenol A, diacrylate of polyoxyalkylenated bisphenol A, 9,9-bis [4- ( 2-acryloyloxyethoxy) phenyl] fluorene and the like.
Examples of (meth) acrylates having 3 or more (meth) acryloyl groups in the molecule include compounds in which 3 mol or more of (meth) acrylic acid is ester-bonded to a polyhydric alcohol having 3 or more hydroxyl groups, for example, Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate Etc.
Moreover, polyether acrylic oligomer, polyester acrylic oligomer, or polyepoxy acrylic oligomer having polyether or polyester in the main chain can also be used.

  Examples of (meth) acrylate having one (meth) acryloyl group in the molecule and having a boiling point at 130 MPa of 0.1 MPa or more include dimethylaminoethyl (meth) acrylate, acryloylmorpholine, dimethylacrylamide, Diethylacrylamide, diisopropylacrylamide, diacetoneacrylamide, isobutoxymethyl (meth) acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, isobornyl (meth) acrylate, dicyclopentenyl acrylate, dicyclopentanyl (meth) acrylate, dicyclo Pentenyloxyethyl (meth) acrylate, 3-hydroxy-1-adamantyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) ) Acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, isoamyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, dicyclopentadienyl (Meth) acrylate, tricyclodecanyl (meth) acrylate, 2-acryloylcyclohexyl succinic acid, tetrahydrofurfuryl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, butoxyethyl (meth) acrylate, alkyl (Meth) acrylate of alcohol which is an adduct of alcohol (1 to 8 carbon atoms) ethylene oxide, alcohol which is an adduct of ethylene oxide of phenol (Meth) acrylate, (meth) acrylate of alcohol which is an adduct of ethylene oxide of p-cumylphenol, (meth) acrylate of alcohol which is an adduct of ethylene oxide of nonylphenol, o-phenylphenol glycidyl ether (meth) acrylate 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, 2-phenoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, 2-ethylhexyl (meth) acrylate, 3-hydroxycyclohexyl acrylate , Tribromophenol ethoxy (meth) acrylate, 2,2,2-trifluoromethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl ( And (meth) acrylate, perfluorooctylethyl (meth) acrylate, and the like.

As these commercial products, Iupimer UV SA1002, SA2007 (above, manufactured by Mitsubishi Chemical Corporation), Biscote # 150, # 155, # 160, # 190, # 192, # 195, # 230, # 215, # 260, # 260 295, # 300, # 335HP, # 360, # 400, # 540, # 700, 3F, 3FM, 4F, 8F, 8FM, 2-MTA, 2-ETA, V-MTG, 3PA, GPT, HEA, HPA, 4-HBA, AIB, IOAA, LA, STA (manufactured by Osaka Organic Chemical Industry Co., Ltd.), light ester M, E, NB, IB, EH, ID, L, L-7, TD, L-8, S , 130MA, 041MA, CH, THF, BZ, PO, IB-X, HO, HOP, HOA, HOP-A, HOB, DM, DE, HO-MS, EG, 2EG, 1.4BG, 1.6HX, 1.9ND, 1.10DC, TMP, G-101P, G-201P, BP-2EM, BP-4EM, BP-6EM, MTG, BO, BC, 3EG, 4EG, 9EG, 14EG, NP, FM-108, G-201P, light acrylate IO-A, HOB-A, TMP-3EO-A, FA-108, IAA, LA, SA, BO-A, EC-A, MTG-A, 130A, DPM-A, PO-A, P-200A, NP-4EA, NP-8EA, THF-A, IB-XA, HOA, HOP-A, M-600A, HOA-MS, 3EG-A, 4EG- A, 9EG-A, 14EG-A, NP-A, MPD-A, 1.6HX-A, BEPG-A, 1.9ND-A, MOD-A, DCP-A, BP-4EA, BP-4PA, BP-10EA, MP-A, TMP-6EO-3A, PE-3A, PE-4A, DPE-6A, BA-104, BA-134 (manufactured by Kyoeisha Chemical Co., Ltd.), KAYARAD MANDA, HX-220, HX-620, R -551, R-712, R-604, R-684, PET-30, GPO-303, TMPTA, DPHA, D-310, D-330, DPCA-20, -30, -60, -120 (above, Nippon Kayaku Co., Ltd.), Aronix M208, M210, M215, M220, M240, M305, M309, M310, M315, M325, M400, M1200, M6100, M6200, M6250, M7100, M8030, M8060, M8100, M8530, M8560, M9050 (above, manufactured by Toagosei Co., Ltd.), NK ester # 401P, N K ester A-BPEF, NK ester A-CMP-1E (above, Shin-Nakamura Chemical Co., Ltd.), New Frontier BR-31 (above, Daiichi Kogyo Seiyaku Co., Ltd.), Lipoxy VR-77, VR-60, VR -90 (above, Showa Polymer Co., Ltd.), Ebecryl 81, 83, 600, 629, 645, 745, 754, 767, 701, 755, 705, 770, 800, 805, 810, 830, 450, 1830, 1870 ( As described above, Daicel UCB), beam sets 575, 551B, 502H, 102 (above, Arakawa Chemical Co., Ltd.), adamantate HA, HM (above, Idemitsu Kosan Co., Ltd.) and the like can be mentioned.
(C) A component is used individually by 1 type or in combination of 2 or more types.
(C) The compounding quantity of a component becomes like this. Preferably it is 5-100 mass parts with respect to 100 mass parts of (A) component, More preferably, it is 10-70 mass parts, Most preferably, it is 20-50 mass parts. When the amount is less than 5 parts by mass, the accuracy of the shape of the core portion of the target optical waveguide may be inferior when forming the optical waveguide. When the amount exceeds 100 parts by mass, the component (A) And the film may become rough on the surface of the cured product (core portion).

[(D) component]
The component (D) is a photo radical polymerization initiator capable of generating an active species (radical species) capable of polymerizing an ethylenically unsaturated group by light irradiation.
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 photo radical polymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2 -Hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthio Xanthone, 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.
Commercially available radical photopolymerization initiators include, for example, Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI 1700, CGI 1750, CGI 11850, CG 24-61, Darocur 1116, 1173 (and above, Ciba Specialty Chemicals). Co., Ltd.), Lucirin TPO, TPO-L (above, manufactured by BASF), Ubekrill P36 (manufactured by UCB), and the like.
A radical photopolymerization initiator is used individually by 1 type or in combination of 2 or more types.

The content rate of (D) component in the photosensitive resin composition of this invention becomes like this. Preferably it is 0.1-10 mass%, More preferably, it is 0.2-5 mass%. When the content 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, if the content exceeds 10% by mass, the photopolymerization initiator may adversely affect long-term transmission characteristics.
In this invention, a photosensitizer can be mix | blended with the above-mentioned photoinitiator. If a photosensitizer is used in combination, energy rays such as light can be absorbed more effectively.
Photosensitizers include, for example, thioxanthone, diethylthioxanthone and thioxanthone derivatives; anthraquinone, bromoanthraquinone and anthraquinone derivatives; anthracene, bromoanthracene and anthracene derivatives; perylene and perylene derivatives; xanthone, thioxanthone and thioxanthone derivatives; And ketocoumarin. What is necessary is just to select the kind of photosensitizer according to the kind of photoinitiator.

[(E) component]
It is preferable that the photosensitive resin composition further contains an organic solvent as the component (E). By mix | blending an organic solvent, while the storage stability of the photosensitive resin composition improves, the suitable viscosity can be provided and the photosensitive resin composition layer which has 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. Specifically, the organic solvent used when preparing (A) component can be used.
Preferable examples of the organic solvent include alcohols, ethers, esters, and ketones. Preferred organic solvent compound names include at least 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, cyclohexanone, toluene, xylene, and methanol. One solvent is mentioned.
The compounding amount of the organic solvent is preferably 10 to 500 parts by mass, more preferably 20 to 300 parts by mass, and particularly preferably 30 to 180 parts by mass with respect to 100 parts by mass of the total amount of the components (A) to (D). Part. When the amount is less than 10 parts by mass, it may be difficult to adjust the viscosity of the photosensitive resin composition. When the amount exceeds 500 parts by mass, it may be difficult to form a photosensitive resin composition layer having a sufficient thickness.

In the photosensitive resin composition, in addition to the components (A) to (E), if necessary, the photosensitive resin composition has, for example, one polymerizable reactive group in the molecule as long as the characteristics of the resin composition are not impaired. Compound, 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, petroleum resin, Xylene resin, ketone resin, cellulose resin, fluorine-based polymer, silicone-based polymer) and the like can be blended.
Furthermore, various additives as necessary, for example, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, coating surface improvers, thermal polymerization inhibitors, leveling agents, surfactants, colorants, Storage stabilizers, plasticizers, lubricants, fillers, inorganic particles, anti-aging agents, wettability improvers, antistatic agents and the like can be blended.
Here, examples of the antioxidant include Irganox 1010, 1035, 1076, 1222 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Antigene P, 3C, FR, and Sumilizer (manufactured by Sumitomo Chemical Co., Ltd.). Examples of ultraviolet absorbers include Tinuvin P, 234, 320, 326, 327, 328, 329, 213 (and above, manufactured by Ciba Specialty Chemicals), Seesorb 102, 103, 110, 501, 202, 712, and 704 (and above). , Manufactured by Sipro Kasei Co., Ltd.). Examples of the light stabilizer include Tinuvin 292, 144, 622LD (manufactured by Ciba Specialty Chemicals), Sanol LS770 (manufactured by Sankyo Co., Ltd.), Sumisorb TM-061 (manufactured by Sumitomo Chemical Co., Ltd.), and the like. Examples of the silane coupling agent include γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like, and commercially available products such as SH6062 and SZ6030 (above, Toray Dow Corning Silicone Co., Ltd.), KBE903, 603, 403 (manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of the coating surface improver include silicone additives such as dimethylsiloxane polyether, and commercially available products include DC-57, DC-190 (manufactured by Dow Corning), SH-28PA, SH-29PA, SH. -30PA, SH-190 (above, manufactured by Toray Dow Corning Silicone), KF351, KF352, KF353, KF354 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), L-700, L-7002, L-7500, FK- 024-90 (manufactured by Nihon Unicar).
In order to prepare the photosensitive resin composition, the components described above may be mixed and stirred according to a conventional method.

The core part-forming dry film used in a reference example described later has a base film and an uncured photosensitive resin composition layer formed on the base film.
In addition, the dry film for core part formation is good also as a structure which has the cover film for protecting the photosensitive resin composition layer further on the photosensitive resin composition layer formed on the base film. In this case, the cover film is peeled off when the core part forming dry film is used.
As a method of forming a photosensitive composition layer on a base film, a method of directly applying the photosensitive composition on a base film, or a method of dissolving the photosensitive composition in an organic solvent, a spin coating method, A method of spraying a solvent using a drier, etc. after applying using a method such as a dipping method, a spray method, a bar coating method, a roll coating method, a curtain coating method, a gravure printing method, a silk screen method, or an ink jet method. Is mentioned.
The temperature condition for scattering the organic solvent is preferably 30 to 150 ° C, more preferably 50 to 140 ° C. The amount of the organic solvent remaining after drying is preferably 20 parts by mass or less based on 100 parts by mass of the photosensitive resin composition after the organic solvent is dispersed. Moreover, the thickness of the photosensitive resin composition layer is usually 3 to 200 μm.

Hereinafter, an example of a method for manufacturing an optical waveguide will be described with reference to the drawings as appropriate. FIG. 1 is a cross-sectional view schematically showing an example of an optical waveguide manufactured by the method of the present invention, and FIG. 2 is a flowchart showing an example of a method for manufacturing the optical waveguide .
[1. Structure of optical waveguide]
In FIG. 1, an optical waveguide 1 has a lower cladding layer 2 formed on a base material (not shown) such as a silicon substrate or a synthetic resin film, and a specific width formed on the upper surface of the lower cladding layer 2. It comprises a core portion 3 having an upper clad layer 4 formed on the core portion 3 and the lower clad layer 2. The core portion 3 is embedded in the lower cladding layer 2 and the upper cladding layer 4.
The thicknesses of the lower clad layer 2, the core portion 3, and the upper clad layer 4 are not particularly limited. For example, the thickness of the lower clad layer 2 is 1 to 200 μm, the thickness of the core portion 3 is 3 to 200 μm, and the upper portion The thickness of the clad layer 4 is determined to be 1 to 200 μm. Although the width | variety of the core part 3 is not specifically limited, For example, it is 1-200 micrometers.
The refractive index of the core portion 3 needs to be higher than any of the refractive indexes of the lower cladding layer 2 and the upper cladding layer 4. For example, for light having a wavelength of 400 to 1,600 nm, the refractive index of the core portion 3 is 1.420 to 1.650, and the refractive indexes of the lower cladding layer 2 and the upper cladding layer 4 are 1.400 to 1.648. In addition, it is preferable that the refractive index of the core portion 3 is at least 0.1% larger than the refractive indexes of the two cladding layers 2 and 4.

[2. Manufacturing method of optical waveguide]
In FIG. 2, in the method of manufacturing the optical waveguide 1, if the steps are divided in the order of forming each part of the optical waveguide 1, the step of forming the lower cladding layer 2 on the base material (not shown) ( a)), a step of forming the core portion 3 on the lower cladding layer 2 (FIGS. 2B to 2E), and an upper cladding layer 22 on the lower cladding layer 2 and the core portion 3 The process ((f) of FIG. 2) to perform is included.
In addition, the photosensitive resin composition prepared in order to form each part of the lower clad layer 2, the core part 3, and the upper clad layer 4 is respectively a lower layer composition, a core composition, and an upper layer composition for convenience. It is called a thing. Also, dry films having an uncured photosensitive resin composition layer composed of a lower layer composition, a core composition, and an upper layer composition are respectively obtained as a lower layer dry film, a core dry film, and an upper layer dry film. It is called a film.

(1) Preparation of photosensitive resin composition Each component composition of the lower layer composition, the core composition, and the upper layer composition is the refractive index of each part of the lower cladding layer 2, the core part 3, and the upper cladding layer 4. Is determined so as to satisfy the conditions required for the optical waveguide. Specifically, two or three types of photosensitive resin compositions having an appropriate difference in refractive index are prepared, and among these, a photosensitive resin composition that gives a cured film having the highest refractive index is prepared. The composition for the core is used, and another photosensitive resin composition is used as the composition for the lower layer and the composition for the upper layer.
The lower layer composition and the upper layer composition are preferably the same photosensitive resin composition in terms of economy and production control.

(2) Preparation of base material A base material having a flat surface is prepared. Although it does not specifically limit as a kind of this base material, For example, a board | substrate consisting of inorganic materials, such as a silicon substrate, a glass substrate, a glass epoxy resin, a polyimide substrate, a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN) etc. A synthetic resin film or sheet can be used.
(3) Formation of lower clad layer In this step, the lower clad layer 2 is formed on the upper surface of the substrate. Specifically, a liquid lower layer photosensitive resin composition is applied to the upper surface of the base material, pre-baked as necessary to form a lower layer thin film, and this lower layer thin film is irradiated with light and cured. Then, the lower cladding layer 2 which is a cured body is formed.
The lower layer photosensitive resin composition is not particularly limited as long as it is a composition capable of forming an optical waveguide.
After the formation of the lower clad layer 2, heat treatment (post-bake) is performed as necessary.
Examples of the method for applying the photosensitive resin composition include spin coating, dipping, spraying, bar coating, roll coating, curtain coating, gravure printing, silk screen, and inkjet.

The lower layer thin film may be pre-baked at a temperature of 50 to 200 ° C. for the purpose of accelerating curing and removing the residual solvent, if necessary.
The radiation dose for forming the lower cladding layer is not particularly limited, but radiation with a wavelength of 200 to 450 nm and an illuminance of 1 to 500 mW / cm ² is applied with a dose 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 radiation to be irradiated, and ultraviolet rays are particularly preferable. For example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, or an excimer lamp is preferably used as the radiation irradiation apparatus. In the step of forming the lower clad layer, it is preferable to irradiate the entire surface of the thin film and cure the whole.
Further, after the exposure, it is preferable to further perform heat treatment (hereinafter referred to as “post-bake”) so that the entire surface of the coating film is sufficiently cured. Although this heating condition changes with the compounding composition of the photosensitive resin composition, the kind of additive, etc., Usually, it is 30-300 degreeC, Preferably it is 50-200 degreeC, for example, if it is set as the heating condition for 5 minutes-72 hours. good.
Note that the radiation dose, type, radiation irradiation apparatus, and the like in the lower clad layer 2 forming step are the same in the core portion forming step and the upper clad layer forming step, which will be described later.
For the lower clad layer 2, a lower layer dry film is prepared in place of the application of the liquid photosensitive resin composition for the lower layer, and the same transfer and light irradiation (however, the entire surface) as the following core dry film is performed. May be formed.

(4) Formation of core part
In a reference example to be described later, the core dry film 10 (a laminate of the base film 11 and the core photosensitive composition layer 12) is placed in a state where the core photosensitive composition layer 12 faces downward and the lower cladding layer. 2 is transferred (laminated) to the upper surface of 2 to form a thin film for the core ((b-1) and (b-2) in FIG. 2).
Here, as a transfer method of the core dry film 10, while applying appropriate heat and pressure using a pressure bonding method such as a normal pressure hot roll pressure bonding method, a vacuum heat roll pressure bonding method, or a vacuum heat press pressure bonding method, The method of transferring to above is mentioned. When the core dry film 10 has a cover film, the core dry film 10 is transferred onto the substrate so that the base film 11 faces upward while peeling the cover film.
In the present invention, as a method for forming the core portion, after applying the liquid core photosensitive composition on the lower clad layer, it is used in the present invention without being dried or in a dried state. film to employ a method of laminating the (number average particle diameter of film made of a synthetic resin containing a filler of 5 to 100 nm). In this case, in order to form the photosensitive composition layer 12 for the core, spin coating method, dipping method, spray method, bar coating method, roll coating method, curtain coating method, gravure printing method, silk screen method, ink jet method, etc. The core photosensitive composition is applied by the method described above. After application, if necessary, pre-baking may be performed at a temperature of 50 to 200 ° C. for the purpose of removing the residual solvent. The base film 11 is laminated on the core photosensitive composition layer.
After that, a photomask 14 having a predetermined pattern, for example, a predetermined line pattern, is placed on the base film 11, and the light 13 (on the core photosensitive composition layer 12 is passed through the photomask 14 and the base film 11. For example, ultraviolet rays are irradiated ((c-1) in FIG. 2). Thereby, in the photosensitive composition layer 12 for cores, only the location irradiated with light hardens | cures, and other parts remain uncured ((c-2) of FIG. 2). Then, the base film 11 is peeled ((d) of FIG. 2).
Next, the uncured portion is developed and removed to form the core portion 3 made of a patterned cured film on the lower cladding layer 2 ((e) of FIG. 2).

Thus, the method of irradiating radiation according to a predetermined pattern is not limited to a method using a photomask composed of a radiation transmitting portion and a non-transmitting portion, and examples thereof include the following methods a to c.
a. A method using electro-optical means for forming a mask image composed of a radiation transmitting region and a radiation 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 using a light guide member formed by bundling a large number of optical fibers and irradiating radiation through the optical fiber corresponding to a predetermined pattern in the light guide member.
c. A method of irradiating laser light or convergent radiation obtained by a condensing optical system such as a lens or a mirror while scanning.

The thin film that has been pattern-exposed and selectively cured in this manner according to a predetermined pattern can be developed using the difference in solubility between the cured portion and the uncured portion. Therefore, after the pattern exposure, while removing the uncured portion and leaving the cured portion, the core portion 3 can be formed as a result.
An organic solvent can be used as the developer used in the development process. Examples of the organic solvent include acetone, methanol, ethanol, isopropyl alcohol, ethyl lactate, propylene glycol monomethyl ether acetate, methyl amyl ketone, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether, and the like.
On the other hand, when the composition forming the core photosensitive composition layer 12 is alkali-soluble, an alkali developer can also be used as the developer. Examples of the alkaline developer include tetramethylammonium hydroxide (TMAH) aqueous solution and potassium hydroxide aqueous solution.
The development time is usually 30 to 600 seconds. As a developing method, a known method such as a liquid piling method, a dipping method, or a shower developing method can be employed. When an organic solvent is used as the developer, the organic solvent is removed by air drying as it is after the development, and the core portion is formed. When an alkali developer is used as the developer, the core portion is formed by rinsing with ion-exchanged water or a shower for 30 to 300 seconds and drying after development.
Next, in order to further cure the patterning portion, post baking is performed, for example, at a temperature of 30 to 400 ° C. for 5 to 600 minutes using a heating device such as a hot plate or an oven.

(5) Formation of upper clad layer After applying the liquid photosensitive composition for upper clad on the lower clad layer 2 and the core portion 3, light irradiation is performed in the same manner as when the lower clad layer is formed, An upper cladding layer 4 is formed. Thus, the optical waveguide 1 is completed.
Instead of the liquid photosensitive composition for upper clad, a dry film for upper clad may be used. In this case, the upper clad layer can be obtained by transferring the upper clad dry film onto the lower clad layer 2 and the core portion 3 and irradiating with light in the same manner as described above. Note that the base film of the upper layer dry film may be peeled off or left as it is.

[Example]
Hereinafter, the present invention will be specifically described by way of examples.
[Preparation of photosensitive resin composition]
First, the following materials were prepared as the components (A) to (D).
[(A) component]
Preparation Example 1
After substituting a flask equipped with a dry ice / methanol reflux with nitrogen, 3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 150 g of ethyl lactate as an organic solvent were stirred until the polymerization initiator was dissolved. did. Subsequently, 20 g of methacrylic acid, 30 g of dicyclopentanyl methacrylate, 25 g of styrene, and 25 g of n-butyl acrylate were charged, and then gently stirred. Thereafter, the temperature of the solution was raised to 80 ° C., and polymerization was carried out at this temperature for 6 hours. Thereafter, 10.5 g of 3,4-epoxycyclohexylmethyl acrylate, 0.8 g of tetrabutylammonium bromide, and 0.1 g of p-methoxyphenol were added to the obtained solution, and the side chain was stirred at 80 ° C. for 7 hours. A polymer solution having an acrylic group was obtained. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After 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 A-1.

Preparation Example 2
After substituting the flask equipped with a dry ice / methanol reflux with nitrogen, 1 g of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator and 150 g of ethyl lactate as an organic solvent were added. Stir until dissolved. Subsequently, 20 g of methacrylic acid, 25 g of dicyclopentanyl methacrylate, 35 g of methyl methacrylate, and 20 g of n-butyl acrylate were charged, and then gently stirred. Thereafter, the temperature of the solution was raised to 70 ° C., and polymerization was carried out at this temperature for 6 hours. Thereafter, 31.4 g of 3,4-epoxycyclohexylmethyl acrylate, 2.2 g of tetrabutylammonium bromide, and 0.1 g of p-methoxyphenol were added to the obtained solution, and the side chain was stirred at 80 ° C. for 7 hours. A polymer solution having an acrylic group was obtained. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After this re-dissolution / coagulation operation was performed three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer A-2.
Table 1 shows the raw material names and blending amounts used in the production of the copolymers A-1 and A-2.

[Component (B)]
In a reaction vessel equipped with a stirrer, 13.6 parts by mass of isophorone diisocyanate, 81.7 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, 4.7 parts by mass of 2-hydroxyethyl acrylate (the total amount of 100 parts by mass above) was dropped, and after completion of the dropping, the mixture was reacted at 50 to 70 ° C. for 1 hour. The reaction was terminated when the residual isocyanate was 0.1% by mass or less, and Compound B-1 was obtained.
[Component (C)]
Trimethylolpropane triacrylate (boiling point at 0.1 MPa: 315 ° C., manufactured by Osaka Organic Chemical Industry Co., Ltd.)
[(D) component]
Photo radical polymerization initiator (trade name: “Irgacure 369”, manufactured by Ciba Specialty Chemicals)
[(E) component]
Ethyl lactate The above-described components (A) to (E) were mixed at the blending ratio shown in Table 2 to obtain photosensitive resin compositions (Compositions 1 and 2).

[ Reference Examples 1 to 4, Comparative Examples 1 to 3]
(1) Preparation of dry film On the base film shown in Table 3, the composition 1 obtained above was applied by spin coating, then dried at 120 ° C for 10 minutes, and further covered on the surface of the dried coating film A polyethylene terephthalate film (film thickness: 25 μm) as a film was pressure-bonded at normal pressure and normal temperature to obtain a dry film for core having a photosensitive resin composition layer thickness of 50 μm. In addition, all the mass ratios of the filler contained in the base film which comprises the dry film for cores were in the range of 0.001-1 mass%.
Moreover, the dry film for lower layers and the upper layer was produced with the thickness of 20 micrometers and 70 micrometers of the photosensitive resin composition layer using the composition 2 obtained above by the same method, respectively.
(2) Formation of lower clad layer The polyethylene terephthalate film, which is a cover film for the lower layer dry film (photosensitive resin composition layer thickness: 20 μm), is peeled off, and the lower layer dry film is placed on the surface of the silicon substrate with a laminator at room temperature. It was transferred by a normal pressure hot roll pressing method. Subsequently, the photosensitive resin composition layer was cured by irradiating with ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² for 100 seconds. The polyethylene terephthalate film, which is the base film, was peeled off and post-baked at 150 ° C. for 1 hour to obtain a lower cladding layer having a thickness of 20 μm.
(3) Formation of the core portion A dry film for core (thickness of the photosensitive resin composition layer: 50 μm) from which the polyethylene terephthalate film, which is a cover film, has been peeled off in advance is pressure-bonded at room temperature and normal pressure with a laminator on the lower clad layer. Transcribed by the method. Thereafter, a photomask having a line pattern having a width of 50 μm is placed on the base film, and ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² are applied to the photosensitive resin composition layer through the photomask and the base film. Irradiate for 100 seconds to cure.
Next, the base film was peeled off, and the substrate having the partially cured photosensitive resin composition layer was immersed in a developer composed of acetone to dissolve unexposed portions of the photosensitive resin composition layer. Thereafter, post-baking was performed at 150 ° C. for 1 hour to form a core portion having a line pattern having a width of 50 μm.
(4) Formation of upper clad layer Next, on the upper surface of the lower clad layer having the core portion, a dry film for upper layer (thickness of the photosensitive resin composition layer: 70 μm) from which the polyethylene terephthalate film as the cover film has been peeled off in advance is applied. It was transferred by a normal pressure hot roll pressure bonding method (temperature: 80 ° C.). Thereafter, ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² were irradiated for 100 seconds, and the polyethylene terephthalate film as a base film was peeled off to form an upper clad layer having a thickness of 70 μm.

[ Comparative Example 4 ]
Without using the core dry film, a liquid photosensitive resin composition (the composition 1) is applied to form a core photosensitive composition layer, and the core photosensitive composition layer is formed on the core photosensitive composition layer. In the same manner as in Reference Example 1 except that a photomask was placed at a predetermined distance above and a light was irradiated and the core photosensitive composition layer was partially cured without placing a film on Thus, an optical waveguide was formed.

[Evaluation of optical waveguide]
Optical waveguides ( Reference Examples 1 to 4, Comparative Examples 1 to 4 ) were evaluated as follows.
(1) Waveguide loss With respect to the optical waveguide, light from an LED having a wavelength of 850 nm was introduced into a graded index fiber having a diameter of 50 μm and made incident from one end of a waveguide having a predetermined length. The outgoing light from the other end of the waveguide was introduced into a graded index fiber having a diameter of 50 μm, and the outgoing light was received by a photodiode. The above loss measurement is performed on an automatic alignment system, and the waveguide loss per unit length (dB / cm) is measured by measuring the received light amount when alignment is performed so that the received light amount of the photodiode is maximized. ) Was determined by the cutback method. In the above measurement, matching oil was used between the light incident side fiber and the waveguide and between the output side waveguide and the fiber. Six measurements were performed, and the average value was defined as the average loss (dB / cm).
(2) Loss variation For the optical waveguide, the standard deviation when the waveguide loss was measured was defined as the loss variation (dB / cm).
The above results are shown in Table 3. The average particle size of the filler was measured with an electron microscope.
The “determination” in Table 3 was evaluated as “◯” when the loss was 0.3 dB / cm or less and the loss variation was 0.1 dB / cm or less, and “x” otherwise. .
In Table 3, waveguide loss is described as “loss”, and loss variation is described as “variation σ”. “Transfer film surface roughness” in Table 3 indicates the surface roughness of the upper surface of the core photosensitive resin composition layer after the base film is peeled off.

From Table 3, the optical waveguide formed by using the dry film ( Reference Examples 1 to 4) has a small waveguide loss despite the light irradiation through the base film to form the core portion, and It can be seen that the loss variation is small. On the other hand, it can be seen that all of the optical waveguides of Comparative Examples 1 to 3 have a large waveguide loss. Further, the optical waveguide of Comparative Example 3 had a large loss variation.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical waveguide 2 Lower clad layer 3 Core part 4 Upper clad layer 10 Core dry film 11 Base film 12 Core photosensitive composition layer 13 Light (ultraviolet)
14 Core pattern forming member (photomask)

Claims (4)

A method of manufacturing an optical waveguide including a lower cladding layer, a core portion, and an upper cladding layer,
On the lower clad layer formed on the substrate, a photosensitive composition for forming a core portion is applied to form a photosensitive composition layer, and then on the photosensitive composition layer. A film lamination step of laminating a film made of a synthetic resin containing a filler having a number average particle diameter of 5 to 100 nm,
In a state where the film is in contact with the photosensitive composition layer, the photosensitive composition layer is irradiated with light through the film to partially cure the photosensitive composition of the photosensitive composition layer. A core pattern forming step of forming a core pattern-containing layer composed of a cured portion and an uncured portion;
After peeling off the film, by developing the core pattern-containing layer, a core part forming step for obtaining a laminate including a lower clad layer and a core part;
And an upper cladding layer forming step of forming an upper cladding layer on the lower cladding layer and the core portion. The method for producing an optical waveguide according to claim 1 , wherein the film has a surface roughness (Ra) of 30 nm or less. The thickness of the film, a method of manufacturing an optical waveguide according to claim 1 or 2 is 300μm or less. The photosensitive composition, a monomer having a (meth) acryloyl group, and a method of manufacturing an optical waveguide according to any one of claims 1 to 3 including a photoradical polymerization initiator.

Images