JP5257090B2 - Optical waveguide - Google Patents

Description

  The present invention relates to an optical waveguide, and more particularly to an optical waveguide having excellent bending resistance.

In high-speed and high-density signal transmission between electronic devices and between wiring boards, signal transmission interference and attenuation become barriers in conventional transmission using electric wiring, and the limits of high-speed and high-density are beginning to appear. In order to overcome this problem, a technique for optically connecting electronic elements and wiring boards, so-called optical interconnection, has been studied.
In order to transmit an optical signal over a short distance such as inside or between devices, a flexible film optical waveguide is desired. In particular, when an optical waveguide is wired inside a small portable device, the component film is often wired so that the surface of the component faces in order to save space. The polymer film optical waveguide can be bent with a small curvature radius. Is required.
In order to improve the flexibility of the flexible optical waveguide or the followability at the interface when the shape is restored, an optical waveguide using a low elastic modulus material has been developed. For example, Patent Documents 1 and 2 propose a film optical waveguide with high bending resistance and high twist resistance in which the bending elastic modulus of the optical waveguide is 1000 MPa or less and the film thickness is 150 μm or less. However, since the optical waveguide is manufactured using a stamper, there are disadvantages that design freedom is low and design change is difficult.

Japanese Patent No. 3870976 Japanese Patent No. 3906870

In general, from the viewpoint of adhesion and production efficiency, a film optical waveguide generally uses the same material for the lower cladding layer and the upper cladding layer, and after forming the core layer, a core pattern is obtained by exposure and development. However, it has been found that in the development process, the lower clad layer may be partially eroded by the developing solvent, which causes a problem that the optical characteristics become insufficient.
The present invention has been made in view of the above problems and the above problems, and an object of the present invention is to provide an optical waveguide that has good bending resistance and is less susceptible to erosion of the lower cladding layer due to solvent development.

As a result of intensive studies to solve the above problems, the present inventors do not necessarily use the same material as the resin composition for forming the lower clad layer and the resin composition for forming the upper clad layer. In other words, the lower clad layer forming material having a small rate of change in film thickness before and after being immersed in the core layer patterning solvent, and the cured film exhibit a predetermined elongation rate. It has been found that the above-mentioned problems can be solved by using together with the material for forming the upper cladding layer.
That is, the present invention is an optical waveguide in which a lower clad layer, a patterned core layer, and an upper clad layer are laminated in this order on a substrate, and the thickness after drying the lower clad layer forming resin composition is 20 μm. The film thickness change rate before and after immersing the film formed so as to become the core layer patterning solvent for 120 seconds is 50% or less, and the upper clad layer forming resin composition comprises the upper clad layer. The present invention provides an optical waveguide characterized in that a 110 μm thick cured film obtained by curing a forming resin composition has a tensile yield elongation at 25 ° C. of 5.5 to 30%.

  The optical waveguide of the present invention has good bending resistance and is less affected by erosion of the lower cladding layer due to solvent development.

It is a figure which shows the manufacturing process of an optical waveguide.

  In the optical waveguide of the present invention, a lower clad layer, a patterned core layer, and an upper clad layer are laminated in this order on a substrate, and the lower clad layer forming resin composition is used when patterning the core layer. The cured film having a thickness of 110 μm formed by curing the upper clad layer-forming resin composition with the resin composition for forming the upper clad layer having a rate of change in film thickness of 50% or less with respect to the solvent. The tensile yield elongation at 25 ° C. is 5.5 to 30%.

(Change rate of film thickness)
The measuring method of the change rate of the film thickness is as follows. That is, for example, a resin composition for forming a lower cladding layer is applied to a polyethylene terephthalate (hereinafter sometimes referred to as “PET”) substrate having a thickness of 25 μm so that the thickness after drying becomes 20 μm. Then, after exposure to 4000 mJ / cm ^{2 at} a wavelength of 365 nm, the sample for measurement is prepared by drying at 80 ° C. for 10 minutes. The thickness T ₁ of the coating film of the measurement sample is measured. Subsequently, the film thickness T ₂ after the sample was immersed in a solvent used for patterning the core layer at 23 ° C. for 120 seconds was measured, and the change rate of the film thickness 100 × (T ₂ −T ₁ ) / T ₁ (%) is obtained.
The rate of change of the film thickness is an index representing the swelling ratio of the resin composition for forming the lower cladding layer with respect to the solvent. If this value is 50% or less, the lower cladding layer is affected by the solvent development of the core layer. Thus, an optical waveguide having good optical characteristics can be obtained. From the above viewpoint, the change rate of the film thickness is more preferably 40% or less.
Moreover, when the swelling ratio with respect to the solvent of the resin composition for lower clad layer formation is too high, the coating film formed with the resin composition for lower clad layer formation may peel from a PET base material. In this case, it is impossible to measure the film thickness T ₂ itself after the immersion, which is included when the film thickness change rate of 50% or less in the present invention cannot be achieved.

The resin composition for forming an upper clad layer used in the present invention has a tensile yield elongation at 25 ° C. of 5.5 to 30 of a cured film having a thickness of 110 μm formed by curing the resin composition for forming an upper clad layer. %, Preferably 5.5 to 25%, more preferably 5.5 to 20%. When the tensile yield elongation is 5.5% or more, it becomes brittle and does not break during bending, which is preferable. If it is 30% or less, the cured film does not easily stretch by the bending test and does not return to the original shape, which is preferable. The tensile yield elongation means the elongation at the time when the film yields in the film tensile test.
If this upper clad layer forming resin composition is used in an optical waveguide, even if a mechanical tensile force is applied, it is absorbed by the upper and lower clad layers, so that the core deformation can be reduced and the transmission characteristics of the optical waveguide can be reduced. Can be prevented.

  As described above, by using an upper clad layer forming material in which the cured film exhibits a predetermined elongation rate, the flexibility of the upper clad layer is improved. Regarding the flexibility of the upper cladding layer, in a bending durability test of a cured film having a thickness of 110 μm formed by curing the resin composition for forming the upper cladding layer, a bending radius of 2 mm, a bending angle of 0 to 180 °, a bending speed of 2 times / It is preferable that no breakage occurs after 80,000 times in a second condition, and more preferably, no mechanical breakage occurs after the bending test is performed 1 million times. If no mechanical breakage occurs in the cured film, the optical waveguide using this film as the cladding layer can perform stable optical transmission for a long period of time, and it should be applied to parts that are always movable, such as the hinge part of mobile phones. Can do. In order to reduce the size of the device, it is required that the optical waveguide does not break even at a smaller radius of curvature. From this viewpoint, it is more preferable that no mechanical breakage occurs when the radius of curvature is 0.5 mm. Mechanical breakage can be confirmed by magnifying glass, under a microscope, or by visual observation.

  Further, in the optical waveguide of the present invention, a cured film having a thickness of 110 μm obtained by curing the resin composition for forming the upper cladding layer has a twist angle of ± 180 ° in the twist endurance test (repetitive twist test), and between the grippers. It is preferable that no mechanical breakage occurs in the cured resin film for forming the upper clad layer after the 80,000 times twist test is performed under the conditions of a distance of 20 mm and a twist rate of 0.5 times / second. More preferably, no mechanical breakage occurs after the 1,000,000 times twist test. If no mechanical breakage occurs in the cured film, the optical waveguide using this film as the cladding layer can perform stable light transmission for a long period of time. For example, it should be applied to a mobile part such as a hinge part of a mobile phone. Can do. Mechanical breakage can be confirmed by magnifying glass, under a microscope, or by visual observation.

  The tensile elastic modulus at 25 ° C. of the cured film obtained by curing the resin composition for forming the upper cladding layer in the optical waveguide of the present invention is preferably 1 to 2000 MPa, more preferably 10 to 1500 MPa, and more preferably 20 to 20 MPa. 1000 MPa is more preferable. When the elastic modulus of the cured film is 2000 MPa or less, when the film is bent in the thickness direction, it can be bent with a small radius of curvature. On the other hand, when the pressure is 1 MPa or more, the cured film returns to its original shape without being stretched when a bending test or a twist test is performed, which is preferable. Film optical waveguides using this cured resin film for forming the upper clad layer are absorbed by the upper and lower clad layers even when a mechanical tensile force is applied, so the core deformation can be reduced, and the transmission characteristics of the film waveguide Can be prevented.

  In the optical waveguide of the present invention, the total light transmittance of a cured film having a thickness of 110 μm obtained by curing the resin composition for forming an upper cladding layer is preferably 50% or more. If the transmittance is 50% or more, the visibility of the core portion in the optical waveguide is good. For example, when the optical waveguide is processed by a dicing saw, the processing can be easily positioned. From the above viewpoint, the transmittance is more preferably 60% or more, and particularly preferably 70% or more. The upper limit of the total light transmittance is not particularly limited.

  In the optical waveguide of the present invention, the haze (cloudiness value) of a cured film having a thickness of 110 μm obtained by curing the resin composition for forming an upper clad layer is preferably 50% or less. If the haze is 50% or less, the visibility of the core portion in the optical waveguide is good. For example, when the outer shape of the optical waveguide is processed by a dicing saw, the processing is easily positioned. From the above viewpoint, the haze is more preferably 40% or less, and particularly preferably 30% or less.

The clad layers (upper clad layer and lower clad layer) in the optical waveguide of the present invention preferably have a refractive index of 1.400 to 1.700 at a wavelength of 830 nm at a temperature of 25 ° C. If the refractive index is 1.400 to 1.700, the refractive index is not significantly different from that of a normal optical resin, so that versatility as an optical material is not impaired. From the above viewpoint, the refractive index of the cladding layer is more preferably 1.425 to 1.675, and particularly preferably 1.450 to 1.650.
Further, the relative refractive index difference between the upper cladding layer and the lower cladding layer is preferably 5% or less. When the relative refractive index difference is 5% or less, the optical properties of the optical waveguide are improved and good adhesion between the upper cladding layer and the lower cladding layer is obtained. From the above viewpoint, the relative refractive index difference between the upper cladding layer and the lower cladding layer is more preferably 4% or less. The relative refractive index difference was determined by the following formula (when the refractive index of the upper cladding layer is high).
Specific refractive index difference (%) = [(refractive index of upper cladding layer) ² − (refractive index of lower cladding layer) ² ] / [2 × (refractive index of upper cladding layer) ² ] × 100

In the optical waveguide of the present invention, the relative refractive index difference between the core portion and the clad layer (upper clad layer and lower clad layer) is preferably 1 to 10%. When it is 1% or more, the light propagating through the core portion at the time of bending does not leak into the cladding layer. When it is 10% or less, the propagation light does not spread too much at the connection portion such as the optical waveguide and the optical fiber, and the coupling loss does not increase. From the above viewpoint, the relative refractive index difference is more preferably 1.5 to 7.5%, and particularly preferably 2 to 7%. In addition, the relative refractive index difference was calculated | required by the formula shown below.
Specific refractive index difference (%) = [(refractive index of core part) ² − (refractive index of clad layer) ² ] / [2 × (refractive index of core part) ² ] × 100
In the optical waveguide of the present invention, since the material of the upper clad and the lower clad may not be the same, it is preferable to bend so that a clad layer having a low refractive index is disposed outside the bent portion or the curved portion. For example, when the outer side of the curved portion of the flexible optical waveguide is bent so as to become the upper clad layer, it is preferable to use a material having a lower refractive index than the upper clad layer.

The resin composition for forming an upper clad used in the optical waveguide of the present invention is not particularly limited as long as the above physical properties are satisfied, but the following compositions are preferable.
That is, the resin for forming the upper clad layer contains (meth) acrylic polymer, modified polyamideimide, or acrylonitrile-butadiene rubber as component (A), and contains a polymerizable compound as component (B). Accordingly, a polymerization initiator is contained as the component (C), and an epoxy resin curing agent is contained as the component (D) as necessary. Hereinafter, each material will be described in detail.

The (meth) acrylic polymer in the component (A) refers to a polymer obtained by polymerizing acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, and derivatives thereof as monomers. The (meth) acrylic polymer may be a homopolymer of the above monomer, or may be a copolymer obtained by polymerizing two or more of these monomers. Furthermore, the copolymer containing said monomer and monomers other than the above may be used in the range which does not inhibit the effect of this invention. Further, it may be a mixture of a plurality of (meth) acrylic polymers. In the present invention, it is preferable to have a reactive functional group and have a weight average molecular weight of 100,000 or more.
(A) The (meth) acrylic polymer having a reactive functional group and having a weight average molecular weight of 100,000 or more includes functional groups such as an epoxy group, an acryloyl group, a methacryloyl group, a carboxyl group, a hydroxyl group, and an episulfide group. What is contained is preferable, and an epoxy group is particularly preferable in terms of crosslinkability. Specifically, an epoxy group-containing (meth) acrylic polymer containing an ethylenically unsaturated group as a raw material monomer and having a weight average molecular weight of 100,000 or more can be mentioned.

As such (meth) acrylic polymer, for example, (meth) acrylic ester copolymer, acrylic rubber, and the like can be used, and acrylic rubber is more preferable. Acrylic rubber is a rubber mainly composed of an acrylate ester and mainly composed of a copolymer such as butyl acrylate and acrylonitrile, a copolymer such as ethyl acrylate and acrylonitrile, or the like.
Examples of the copolymer monomer include butyl (meth) acrylate, ethyl acrylate, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, acrylonitrile and the like.

When an epoxy group is selected as the reactive functional group, it is preferable to use an ethylenically unsaturated epoxide as the copolymer monomer component.
The ethylenically unsaturated epoxide is not particularly limited, and examples thereof include glycidyl (meth) acrylate, α-ethyl glycidyl (meth) acrylate, α-propyl glycidyl (meth) acrylate, α-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-epoxyheptyl (meth) acrylate, α-ethyl -6,7-epoxyheptyl (meth) acrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3,4-epoxycyclohexylmethyl (meth) acrylate, , 4-epoxycyclohexyl ethyl (meth) acrylate, 3,4-epoxycyclohexyl methyl (meth) acrylate, 3,4-epoxycyclohexyl-butyl (meth) acrylate. Among these, from the viewpoint of transparency and heat resistance, glycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl ( (Meth) acrylate is preferred.
Such an epoxy group-containing (meth) acrylic polymer having a weight average molecular weight of 100,000 or more can be produced by appropriately selecting a monomer from the above monomers, or a commercially available product (for example, HTR manufactured by Nagase ChemteX Corporation). -860P-3, HTR-860P-5, etc.). HTR-860P-3 has a weight average molecular weight of 800,000 and an epoxy equivalent (EEW) of 4,809 g / eq, and has a structure represented by the following formula.

  (A) In a (meth) acrylic polymer having a reactive functional group and a weight average molecular weight of 100,000 or more, the number of reactive functional groups is important because it affects the crosslink density, and also varies depending on the resin used. However, when the (meth) acrylic polymer is obtained as a copolymer of a plurality of monomers, the amount of the reactive functional group-containing monomer used as a raw material includes about 0.5 to 6.0% by mass of the copolymer. It is preferable that

  When the epoxy group-containing (meth) acrylic polymer is used as the component (A), the amount of the ethylenically unsaturated epoxide used as a raw material is preferably 0.5 to 6.0% by mass of the copolymer, 0.5 -5.0 mass% is more preferable, and 0.8-5.0 mass% is especially preferable. When the amount of the epoxy group-containing repeating unit is within this range, the epoxy group is gradually crosslinked, so that a cured film having an appropriate elastic modulus that can withstand a bending test, a torsion test and the like can be obtained.

  Other functional groups may be incorporated into the ethylenically unsaturated epoxide to form a monomer. The mixing ratio in that case is determined in consideration of the glass transition temperature (hereinafter referred to as “Tg”) of the epoxy group-containing (meth) acrylic polymer, and Tg is preferably −10 ° C. or higher. This is because when the Tg is −10 ° C. or higher, the tackiness of the resin film for forming the upper clad layer is appropriate, and no problem is caused in handleability.

  (A) In the case of using an epoxy group-containing (meth) acrylic polymer by polymerizing the above monomer as a (meth) acrylic polymer having a reactive functional group and a weight average molecular weight of 100,000 or more, the polymerization There is no restriction | limiting in particular as a method, For example, methods, such as pearl polymerization and solution polymerization, can be used.

  (A) The weight average molecular weight of the (meth) acrylic polymer is preferably 100,000 or more, more preferably 100,000 to 3,000,000, particularly preferably 300,000 to 3,000,000, and 500,000 to Most preferred is 2 million. If the weight average molecular weight is 100,000 or more, the strength and flexibility in sheet form and film form are sufficient, and tackiness does not increase. On the other hand, if it is 3 million or less, the compatibility with the polymerizable compound described later is good, the flow property is sufficient, and the core embedding property does not deteriorate. In the present invention, the weight average molecular weight is a value measured by gel permeation chromatography and converted using a standard polystyrene calibration curve.

Next, the modified polyamideimide in component (A) is preferably silicone-modified polyamideimide and / or butadiene-modified polyamideimide.
The silicone-modified polyamideimide is a polymer having a siloxane skeleton, an imide bond, and an amide bond. ), And an aromatic unit represented by the following general formula (A2), an alicyclic unit represented by the following general formula (A3), and a general formula (A4) And those having an aromatic unit.

(In the formula, R ⁴ and R ⁵ each independently represents a divalent organic group, R ^{6 to} R ⁹ each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 18 carbon atoms, n is an integer of 1 to 50.)

(Wherein X has the following structure)

  Next, the butadiene-modified polyamideimide used for the component (A) of the present invention will be described. The butadiene-modified polyamideimide is a polymer having a polybutadiene skeleton, an imide bond and an amide bond, and examples thereof include those having a repeating unit represented by the following general formula (A ′) and / or (A ″). In polybutadiene, some or all of the double bonds may be hydrogenated.

  In the formula, p represents an integer of 1 to 50, and R and R ′ in all repeating units represent an aromatic unit represented by the general formula (A2) and a fat represented by the general formula (A3). A cyclic unit has an aromatic unit represented by the general formula (A4).

  The weight average molecular weight of the component (A) modified polyamideimide is preferably 30,000 to 300,000, more preferably 40,000 to 200,000, and 50,000 to 100,000. It is particularly preferred. When the weight average molecular weight is 30,000 or more, the strength and flexibility in the film state are improved, and an increase in tackiness can be suppressed. On the other hand, if it is 300,000 or less, the flexibility and adhesiveness in a film state can be improved.

Next, the acrylonitrile-butadiene rubber used for the component (A) of the present invention will be described.
There is no restriction | limiting in particular as an acrylonitrile-butadiene rubber, A well-known thing can be used individually or in combination of 2 or more types. The acrylonitrile-butadiene rubber is obtained by emulsion copolymerization of acrylonitrile and butadiene, and the acrylonitrile content is preferably in the range of 5 to 60% by mass, more preferably in the range of 15 to 40% by mass. When the content of acrylonitrile is within this range, compatibility with (meth) acrylate and epoxy resin is good, and adhesion with other resins is also good.

  (A) The weight average molecular weight of acrylonitrile-butadiene rubber is preferably 100,000 or more, more preferably 100,000 to 3,000,000, still more preferably 300,000 to 3,000,000, and 500,000 to 200. It is particularly preferable that the number is 10,000. If the weight average molecular weight is 100,000 or more, sufficient strength and flexibility in sheet form and film form are obtained, and tackiness does not increase. On the other hand, if it is 3 million or less, the compatibility with (meth) acrylate and epoxy resin is good, the flow property is sufficient, and the core embedding property does not deteriorate.

  (A) The acrylonitrile-butadiene rubber preferably has a reactive functional group. Preferred examples of the reactive functional group include a functional group such as a carboxyl group, an epoxy group, a hydroxyl group, an episulfide group, an aldehyde group, an epoxy group, an amide group, a vinyl group, an amino group, an isocyanate group, or an allyl group. . Among these, a carboxyl group is preferable in terms of crosslinkability. There is no restriction | limiting in particular in the coupling | bonding position in the acrylonitrile-butadiene rubber molecule of these functional groups, For example, you may couple | bond with the terminal of the principal chain and may couple | bond as a side chain. Alternatively, it may be a copolymer of acrylonitrile and butadiene rubber and a reactive functional group-containing monomer.

  When a carboxyl group is selected as the reactive functional group, (meth) acrylic acid, crotonic acid, cinnamic acid, succinic acid (2- (meth) acryloyloxyethyl), 2-phthaloyl are used as copolymer monomer components. Ethyl (meth) acrylate, 2-tetrahydrophthaloylethyl (meth) acrylate, 2-hexahydrophthaloylethyl (meth) acrylate, ω-carboxy-polycaprolactone mono (meth) acrylate, 3-vinylbenzoic acid, 4-vinyl It is preferable to use a compound containing an ethylenically unsaturated group such as benzoic acid and a carboxy group.

  (A) In acrylonitrile-butadiene rubber, since the number of reactive functional groups affects the crosslink density, when the reactive functional group-containing acrylonitrile-butadiene rubber is obtained as a copolymer of a plurality of monomers, the reaction used as a raw material The amount of the functional functional group-containing monomer is preferably about 0.5 to 6.0% by mass of the copolymer.

  When the carboxyl group-containing acrylonitrile-butadiene rubber is used as the component (A), the amount of the carboxyl group-containing repeating unit is preferably 0.5 to 6.0 mass% of the copolymer, and 0.5 to 5.0 mass. % Is more preferable, and 0.8 to 5.0% by mass is particularly preferable. When the amount of the carboxyl group-containing repeating unit is within this range, since the carboxyl group is slowly crosslinked, a cured film having an appropriate elastic modulus that can withstand a bending test, a torsion test, and the like can be obtained.

Other functional groups can also be incorporated into the carboxyl group-containing monomer. The mixing ratio in that case is determined in consideration of the glass transition temperature (hereinafter referred to as “Tg”) of the carboxyl group-containing acrylonitrile-butadiene rubber, and Tg is preferably −10 ° C. or higher. This is because when the Tg is −10 ° C. or higher, the tackiness of the resin film for forming the upper clad layer is appropriate, and no problem is caused in handleability.
(A) When the above monomer is copolymerized as acrylonitrile-butadiene rubber, the polymerization method is not particularly limited, and for example, methods such as emulsion polymerization, pearl polymerization, and solution polymerization can be used.
In addition, the said component used as (A) component can be used individually by 1 type or in combination of 2 or more types.

Next, the polymerizable compound (B) in the upper clad layer forming resin composition will be described.
As the component (B), (meth) acrylate can be used, and the (meth) acrylate is not particularly limited. For example, any of monofunctional, bifunctional, or trifunctional or more polyfunctional ones can be used. Can be used.
There is no restriction | limiting in particular as monofunctional (meth) acrylate, For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) Acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, butoxyethyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate , Octyl heptyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate Tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3- Aliphatic (meth) acrylates such as chloro-2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate; cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, dicyclopentanyl Alicyclic (meth) acrylates such as (meth) acrylate, dicyclopentenyl (meth) acrylate, isobornyl (meth) acrylate; phenyl (meth) acrylate, Nylphenyl (meth) acrylate, p-cumylphenyl (meth) acrylate, o-biphenyl (meth) acrylate, 1-naphthyl (meth) acrylate, 2-naphthyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxy-3- Phenoxypropyl (meth) acrylate, 2-hydroxy-3- (o-phenylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (1-naphthoxy) propyl (meth) acrylate, 2-hydroxy-3- (2 -Aromatic (meth) acrylates such as naphthoxy) propyl (meth) acrylate; 2-tetrahydrofurfuryl (meth) acrylate, N- (meth) acryloyloxyethyl hexahydrophthalimide, 2- (meth) acryloyloxyethyl-N- Mosquito Examples thereof include heterocyclic (meth) acrylates such as rubazole; ethoxylated products thereof; propoxylated products thereof; ethoxylated propoxylated products thereof; modified caprolactones thereof and the like.
Among these, from the viewpoint of transparency and compatibility with (meth) acrylic polymers, the above aliphatic (meth) acrylates; the above alicyclic (meth) acrylates; the above heterocyclic (meth) acrylates; These propoxylated compounds; these ethoxylated propoxylated compounds; and these caprolactone-modified products are preferable.

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

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

As the component (B), an epoxy resin can be used, and the epoxy resin is not particularly limited. For example, a wide range of epoxy resins described in an epoxy resin handbook (edited by Masaki Shinbo, Nikkan Kogyo Shimbun), etc. Can do. Specifically, for example, hydroquinone type epoxy resin, resorcinol type epoxy resin, catechol type epoxy resin, bisphenol A type epoxy resin, tetrabromobisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, bisphenol AD Type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, etc. bifunctional phenol glycidyl ether type epoxy resin; hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated 2,2 Hydrogenated bifunctional phenol glycidyl ether type epoxy resin such as' -biphenol type epoxy resin, hydrogenated 4,4'-biphenol type epoxy resin; phenol novolac type epoxy resin, Crezo Polyfunctional glycol glycidyl ether type epoxy resin having 3 or more functional groups such as luminolac type epoxy resin, dicyclopentadiene-phenol type epoxy resin, dicyclopentadiene-cresol type epoxy resin, tetraphenylolethane type epoxy resin, etc .; polyethylene glycol type epoxy resin , Polypropylene glycol type epoxy resin, neopentyl glycol type epoxy resin, 1,6-hexanediol type epoxy resin, etc. bifunctional aliphatic alcohol glycidyl ether type epoxy resin; cyclohexanediol type epoxy resin, cyclohexanedimethanol type epoxy resin, tri Bifunctional alicyclic alcohol glycidyl ether type epoxy resin such as cyclodecanedimethanol type epoxy resin; Trimethylolpropane type epoxy resin Polyfunctional aliphatic alcohol glycidyl ether type epoxy resin such as sorbitol type epoxy resin and glycerin type epoxy resin; bifunctional aromatic glycidyl ester such as diglycidyl phthalate; tetrahydrophthalic acid diglycidyl ester, hexahydro Bifunctional alicyclic glycidyl esters such as diglycidyl phthalate; bifunctional aromatic glycidyl amines such as N, N-diglycidylaniline and N, N-diglycidyltrifluoromethylaniline; N, N, N ′, N Trifunctional or more polyfunctional aroma such as' -tetraglycidyl-4,4-diaminodiphenylmethane, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, O-triglycidyl-p-aminophenol Glycidylamine; Alicyclic Bifunctional alicyclic epoxy resins such as diepoxy acetal, alicyclic diepoxy adipate, alicyclic diepoxy carboxylate, vinylcyclohexene dioxide; 1,2-bis (hydroxymethyl) -1-butanol 1,2 -Trifunctional or higher polyfunctional alicyclic epoxy resin such as epoxy-4- (2-oxiranyl) cyclohexane adduct; Trifunctional or higher polyfunctional heterocyclic epoxy resin such as triglycidyl isocyanurate; Organopolysiloxane type epoxy Silicon-containing bifunctional or trifunctional or higher polyfunctional epoxy resins such as resins are exemplified.
Among these, from the viewpoint of transparency and compatibility with (meth) acrylic polymer, hydroquinone type epoxy resin, resorcinol type epoxy resin, catechol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type Bifunctional phenol glycidyl ether type liquid epoxy resin such as epoxy resin and bisphenol AD type epoxy resin; the above bifunctional alicyclic liquid epoxy resin is preferable.
These compounds can be used alone or in combination of two or more.

As the component (B), urethane (meth) acrylate can be used, and the urethane (meth) acrylate is not particularly limited. For example, a reaction between a hydroxyl group-containing (meth) acrylate and a polyisocyanate or a hydroxyl group-containing (meth) acrylate. Well-known urethane acrylate obtained by reaction of polyisocyanate and polyol can be used. From the viewpoint of compatibility with the (meth) acrylic polymer, urethane (meth) acrylate obtained by reaction of a hydroxyl group-containing (meth) acrylate and polyisocyanate is preferable.
As urethane acrylate obtained by reaction of hydroxyl group-containing (meth) acrylate and polyisocyanate, for example, hydroxyethyl (meth) acrylate and 2,5- or 2,6-bis (isocyanatomethyl) -bicyclo [2.2.1]. ] Heptane reaction product, hydroxyethyl (meth) acrylate and 2,4-tolylene diisocyanate reaction product, hydroxyethyl (meth) acrylate and isophorone diisocyanate reaction product, hydroxypropyl (meth) acrylate and 2, 4-tolylene diisocyanate reaction product, hydroxypropyl (meth) acrylate and isophorone diisocyanate reaction product, phenyl glycidyl ether (meth) acrylate and hexamethylene diisocyanate reaction product, Reaction product of diether and toluene diisocyanate, reaction product of pentaerythritol triacrylate and hexamethylene diisocyanate, reaction product of pentaerythritol triacrylate and toluene diisocyanate, reaction product of pentaerythritol triacrylate and isophorone disissocyanate, di Examples include a reaction product of pentaerythritol pentaacrylate and hexamethylene diisocyanate.

Examples of the polyol used when producing a urethane acrylate obtained by the reaction of a hydroxyl group-containing (meth) acrylate, a polyisocyanate and a polyol include polyether diol, polyester diol, polycarbonate diol, and polycaprolactone diol.
Polyether diols include aliphatic, alicyclic, and aromatic types.
These polyols can be used alone or in combination of two or more.

As the polyol, a dihydric or higher polyol synthesized by a reaction between a diol and a polyisocyanate can also be used.
The polymerization mode of each structural unit in these polyols is not particularly limited, and may be any of random polymerization, block polymerization, and graft polymerization.
Examples of the aliphatic polyether diol include ring-opening copolymerization of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, and two or more ion-polymerizable cyclic compounds. Polyether diol obtained by the above.

  Examples of the ion polymerizable cyclic compound include ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, and tetraoxane. , Cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monooxide, isoprene monooxide, vinyl oxetane, vinyl tetrahydrofuran, vinyl cyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, glycidyl benzoate And cyclic ethers.

  Specific examples of polyether diols obtained by ring-opening copolymerization of two or more of the above ion-polymerizable cyclic compounds include, for example, tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and the like. Binary copolymers obtained from combinations of ethylene oxide, propylene oxide and ethylene oxide, butene-1-oxide and ethylene oxide; terpolymers obtained from combinations of tetrahydrofuran, butene-1-oxide and ethylene oxide .

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

In the present invention, (C) a polymerization initiator can be used as necessary. The polymerization initiator of component (C) is not particularly limited as long as the polymerization is initiated by heating or irradiation with actinic rays such as ultraviolet rays and visible rays. For example, a thermal radical polymerization initiator, a photo radical polymerization initiator, A thermal cationic polymerization initiator, a photocationic polymerization initiator, etc. are mentioned. Moreover, when using the said polyfunctional (meth) acrylate (photoreactive monomer) as (B) polymeric compound, a photobase generator can be used.
The thermal radical polymerization initiator is not particularly limited, and examples thereof include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (t-butylperoxy) cyclohexane, 1,1 -Bis (t-butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane Peroxyketals such as 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane; hydroperoxides such as p-menthane hydroperoxide; α, α′-bis (t-butyl Peroxy) diisopropylbenzene, dicumyl peroxide, t- Dialkyl peroxides such as tilcumyl peroxide and di-t-butyl peroxide; diacyl peroxides such as octanoyl peroxide, lauroyl peroxide, stearyl peroxide and benzoyl peroxide; bis (4-t-butylcyclohexyl) peroxide Peroxycarbonates such as oxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-3-methoxybutyl peroxycarbonate; t-butyl peroxypivalate, t- Hexyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, t -Hexilper Oxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy-3,5 5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, Peroxyesters such as 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane and t-butylperoxyacetate; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2 , 4-Dimethylvaleronitrile), 2,2'-azobi (4-methoxy-2'-dimethylvaleronitrile) azo compounds and the like.
Of these, diacyl peroxides, peroxyesters, and azo compounds are preferred from the viewpoints of curability and transparency.

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

The thermal cationic polymerization initiator is not particularly limited, and examples thereof include benzylsulfonium salts such as p-alkoxyphenylbenzylmethylsulfonium hexafluoroantimonate; benzyl-p-cyanopyridinium hexafluoroantimonate, 1-naphthylmethyl-o- Examples include pyridinium salts such as cyanopyridinium hexafluoroantimonate and cinnamyl-o-cyanopyridinium hexafluoroantimonate; and benzylammonium salts such as benzyldimethylphenylammonium hexafluoroantimonate.
Among these, the benzylsulfonium salt is preferable from the viewpoints of curability and transparency.

The photocationic polymerization initiator is not particularly limited, and examples thereof include aryl diazonium salts such as p-methoxybenzenediazonium hexafluorophosphate, diaryliodonium salts such as diphenyliodonium hexafluorophosphate, and diphenyliodonium hexafluoroantimonate; triphenylsulfonium Hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium hexafluorophosphate, diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate, diphenyl-4-thiophenoxyphenylsulfonium pentafluorohydroxyantimonate Triarylsulfonium salts such as; Triarylselenonium salts such as nylselenonium hexafluorophosphate, triphenylselenonium tetrafluoroborate, triphenylselenonium hexafluoroantimonate; dimethylphenacylsulfonium hexafluoroantimonate, diethylphenacylsulfonium hexafluoroantimonate, etc. Dialkylphenacylsulfonium salts; dialkyl-4-hydroxy salts such as 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate, 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate; α-hydroxymethylbenzoin sulfonate, N-hydroxyimide Sulfonates, α-sulfonyloxy ketones, β-sulfonyloxy ketones, etc. Such as phosphate esters.
Among these, the triarylsulfonium salt is preferable from the viewpoint of curability and transparency.
These thermal and photocationic polymerization initiators can be used alone or in combination of two or more. Furthermore, it can also be used in combination with an appropriate sensitizer.

  The photobase generator in the present invention is generally called an α-aminoketone compound. Such compounds are described, for example, in J. Org. Photopolym. Sci. Technol, Vol. 13, No. 20001, etc., and reacts as shown in the following formula when irradiated with ultraviolet rays.

  Since the α-aminoketone compound does not have radicals before being irradiated with ultraviolet rays, a polymerization reaction of a photoreactive monomer such as a polyfunctional (meth) acrylate does not occur. In addition, curing of the thermosetting resin is not accelerated due to steric hindrance. However, the α-aminoketone compound is dissociated by ultraviolet irradiation, and a polymerization reaction of the photoreactive monomer occurs with the generation of radicals. In addition, dissociation of the α-aminoketone compound causes steric hindrance to be reduced and activated amines to be present. For this reason, it is presumed that the amine has a curing accelerating action of the thermosetting resin, and the heating accelerating action is subsequently exerted by heating. By such an action, there is no radical or activated amine before the ultraviolet irradiation, so that it is possible to provide a resin composition for forming an upper cladding layer that is very excellent in storage stability at room temperature. . Moreover, since the cure rate of a photoreactive monomer or an epoxy resin changes with the structure of the radical and amine which generate | occur | produce by ultraviolet irradiation, a photobase generator can be determined with the (B) polymeric compound to be used.

The photobase generator is not particularly limited as long as it is a compound that generates radicals and activated amines upon irradiation with ultraviolet rays. For example, 2-benzyl-2-dimethylamino-1- (4-morpholine- 4-ylphenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-ylphenyl) -butan-1-one, 1,2- Α-amino ketones such as methyl-1- [4- (methylthio) phenyl]-(4-morpholin) -2-ylpropan-1-one; bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphineoxy Phosphine oxides such as 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o- Fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer And 2,4,5-triarylimidazole dimer and the like.
In the 2,4,5-triarylimidazole dimer, the substituents of the aryl groups at the two triarylimidazole sites may give the same and symmetric compounds, but give differently asymmetric compounds. May be.
Among these, from the viewpoint of curability and transparency, the α-aminoketone is preferable.
The above photobase generators can be used alone or in combination of two or more. Furthermore, it can also be used in combination with other thermal radical polymerization initiators, photo radical polymerization initiators, and appropriate sensitizers.

In the resin composition for forming an upper clad layer of the present invention, (D) an epoxy resin curing agent can be used as needed, and in particular, a phenol-based epoxy resin curing agent can be suitably used. The phenolic epoxy resin curing agent is not particularly limited. For example, hydroquinone, resorcinol, catechol, bisphenol A, tetrabromobisphenol A, bisphenol F, bisphenol AF, bisphenol AD, biphenol, dihydroxynaphthalene, binaphthol, fluorene type bisphenol, etc. Bifunctional phenols: phenol novolak resin, cresol novolak resin, triazine ring-containing phenol novolak resin, triazine ring-containing cresol novolak resin, bisphenol A novolak resin, tetrabromobisphenol A novolak resin, bisphenol AF novolak resin, bisphenol AD novolak resin, biphenol Novolac resin, fluorene type bisphenol novolac resin, di Black cyclopentadiene - - phenol novolak resin, dicyclopentadiene novolak resins such as cresol novolak resins; phenolic resole resins, such as resole resins and cresol resol resin.
Of these, bifunctional phenols such as hydroquinone, resorcinol, catechol, bisphenol A, bisphenol F; phenol novolac resin, cresol novolac resin, bisphenol A novolac resin, from the viewpoint of transparency and compatibility with (meth) acrylic polymers It is preferable that it is novolak resin.
These compounds can be used alone or in combination of two or more.

The amine-based epoxy resin curing agent is not particularly limited, and chain fats such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, diethylaminopropylamine, dicyandiamide, tetramethylguanidine, triethanolamine and the like. Group amine; isophoronediamine, diaminodicyclohexylmethane, bis (aminomethyl) cyclohexane, bis (4-amino-3-methyldicyclohexyl) methane, N-aminoethylpiperazine, 3,9-bis (3-aminopropyl) -2, Cycloaliphatic amines such as 4,8,10-tetraoxaspiro [5.5] undecane; xylenediamine, phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, 2,2- And aromatic amines such as bis [4- (4-aminophenoxy) phenyl] propane.
These compounds can be used alone or in combination of two or more.

  The resin composition for forming an upper clad layer in the optical waveguide of the present invention may further contain (E) a curing accelerator as necessary.

The (E) curing accelerator used in the present invention is not particularly limited, and examples thereof include secondary amines such as tri-n-butylamine, benzylmethylamine, and methylaniline; triethylamine, tri-n-propylamine, Tertiary amines such as isopropylamine, tri-n-butylamine, diethylisopropylamine, benzyldimethylamine, N, N-dimethylaniline, N, N, N ′, N′-tetramethylethylenediamine; pyrrolidine, N-methylpyrrolidine, Piperidine, N-methylpiperidine, morpholine, N-methylmorpholine, piperazine, N, N′-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane, 1,5-diazabicyclo [4.3. 0] Nona-5-ene, 1,8-diazabicyclo [5.4.0] unde Cyclic amines such as -7-ene; 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1,2-dimethylimidazole, 2-ethyl-1-methyl Imidazole, 1,2-diethylimidazole, 1-ethyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 4-ethyl-2-methylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2 -Phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4, 5-dihydroxymethyl Midazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)] ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)] ethyl-s-triazine, 2,4-diamino-6- [2′- Imidazole compounds such as ethyl-4′-methylimidazolyl- (1 ′)] ethyl-s-triazine; trimellitic acid adducts of the imidazole compounds; isocyanuric acid adducts of the imidazole compounds; hydrobromic acid additions of the imidazole compounds Body; tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium iodide, salt Benzyltrimethylammonium bromide benzyltrimethylammonium, and the like quaternary ammonium salts such as benzyl iodide trimethylammonium.
Among these, from the viewpoint of transparency and curability, the imidazole compound; the trimellitic acid adduct of the imidazole compound; and the isocyanuric acid adduct of the imidazole compound are preferable.
These compounds can be used alone or in combination of two or more.

  If necessary, the resin composition for forming an upper clad layer of the present invention includes fillers such as inorganic fillers and organic fillers, silane coupling agents such as silane, titanium, and aluminum, antioxidants, yellow You may add what is called additives, such as a change inhibitor, a ultraviolet absorber, a visible light absorber, a coloring agent, a plasticizer, a stabilizer, a filler, in the ratio which does not have a bad influence on the effect of this invention.

  The resin composition for forming an upper clad layer used in the present invention is not particularly limited as long as the effects of the present invention are achieved. For example, it contains the constituent components shown in the following first to seventh aspects. It is preferable that

  As a first aspect of the resin composition for forming an upper clad layer used in the present invention, (A) a (meth) acrylic polymer having a reactive functional group and having a weight average molecular weight of 100,000 or more, (B) an epoxy It is preferable to contain a resin, (D) a phenolic epoxy resin curing agent, and (E) a curing accelerator as required.

  In the first embodiment, the amount of (A) (meth) acrylic polymer added is (B) an epoxy resin and (D) a phenol-based epoxy resin curing agent, from the viewpoint of elastic modulus reduction and flow control during molding. When the total weight of A is A and the weight of the (A) (meth) acrylic polymer is B, the ratio A / B is preferably 0.24 to 1.0. If the above blending ratio is 0.24 or more, the elastic modulus is reduced and the flowability suppressing effect at the time of molding is obtained. On the other hand, if it is 1.0 or less, the handleability at high temperatures can be improved. .

  In the first aspect, the blending amount of the (D) phenolic epoxy resin curing agent is not particularly limited as long as the epoxy group curing reaction can proceed, but preferably, with respect to 1 mol of the epoxy group of the epoxy resin. In the range of 0.01 to 5.0 equivalents, particularly preferably in the range of 0.8 to 1.2 equivalents.

  Said 1st aspect WHEREIN: It is preferable that the compounding quantity of (E) hardening accelerator shall be 0-5.0 mass% with respect to the total amount with an epoxy resin and a phenol type epoxy resin hardening | curing agent, 0.05- It is more preferable to set it as 3.0 mass%, and it is more preferable to set it as 0.2-3.0 mass% further. When the blending amount of the curing accelerator is 5.0% by mass or less, the storage stability is improved and the pot life is sufficient.

As a second embodiment of the resin composition for forming an upper clad layer used in the present invention, (A) a (meth) acrylic polymer having a reactive functional group and having a weight average molecular weight of 100,000 or more, (B) an epoxy It is preferable to contain a resin and a photoreactive monomer, (C) a photobase generator, and (D) a phenolic epoxy resin curing agent.
In addition, a photoreactive monomer is a monomer which superposes | polymerizes by irradiation of light here, and the above-mentioned polyfunctional (meth) acrylate is mentioned as a suitable thing.

  In the second aspect, the amount of the (B) epoxy resin used is preferably 5 to 250 parts by mass with respect to 100 parts by mass of the (A) (meth) acrylic polymer. When it is within this range, it is possible to ensure the elastic modulus and flowability during molding, and to obtain sufficient handleability at high temperatures. (B) As for the usage-amount of an epoxy resin, 10-100 mass parts is more preferable, and 20-50 mass parts is especially preferable.

  The said 2nd aspect WHEREIN: As for the usage-amount of (B) photoreactive monomer, 5-100 mass parts is preferable with respect to 100 mass parts of (A) (meth) acrylic polymer. If the blending amount is 5 parts by mass or more, the polymerization reaction of the photoreactive monomer is likely to occur, so that the peelability from the support substrate tends to be improved. If it is 100 parts by mass or less, the low elasticity of the (meth) acrylic polymer functions, and the flex resistance is improved without the film becoming brittle. Therefore, 10-70 mass parts is more preferable, and 20-50 mass parts is especially preferable.

  In the said 2nd aspect, the usage-amount of (C) photobase generator is 0.1-20 mass parts with respect to 100 mass parts of (A) (meth) acrylic polymer. If it is 0.1 part by mass or more, the reactivity can be improved and the residual monomer can be reduced, and if it is 20 parts by mass or less, the molecular weight increase due to the polymerization reaction can be functioned well and the low molecular weight component can be reduced. The reflow resistance can be improved. Therefore, it is preferably 0.5 to 15 parts by mass, and more preferably 1 to 5 parts by mass.

  In the second aspect, the amount of (D) phenolic epoxy resin curing agent used is preferably such that the equivalent ratio of phenolic hydroxyl groups per epoxy group of the epoxy resin is in the range of 0.5 to 1.5. 0.8 to 1.2 is more preferable. If it is this range, hardening (crosslinking) of resin will become enough, a glass transition temperature will go up, and the moisture resistance of a hardening | curing agent can be improved.

  As a third aspect of the resin composition for forming an upper clad layer used in the present invention, (A) a (meth) acrylic polymer having a reactive functional group and having a weight average molecular weight of 100,000 or more, (B) ( It is preferable to contain a (meth) acrylate and an epoxy resin, (C) a radical photopolymerization initiator, and (D) a phenolic epoxy resin curing agent.

  In the said 3rd aspect, the usage-amount of the (meth) acrylate of (B) component has preferable 5-100 mass parts with respect to 100 mass parts of (A) (meth) acrylic polymer. If the blending amount is 5 parts by mass or more, the polymerization reaction of (meth) acrylate is likely to occur, so that the peelability from the support substrate tends to be improved. If it is 100 parts by mass or less, the low elasticity of the (meth) acrylic polymer functions, and the flex resistance is improved without the film becoming brittle. Therefore, 10-70 mass parts is more preferable, and 20-50 mass parts is especially preferable.

  In the said 3rd aspect, 5-250 mass parts is preferable with respect to 100 mass parts of (A) (meth) acrylic polymers, and the usage-amount of the epoxy resin of (B) component. When it is within this range, it is possible to ensure the elastic modulus and flowability during molding, and to obtain sufficient handleability at high temperatures. As for the usage-amount of an epoxy resin, 10-100 mass parts is more preferable, and 20-50 mass parts is especially preferable.

  In the third aspect, the compounding amount of the photoradical polymerization initiator of the component (C) is 0.01 to 100 parts by mass with respect to 100 parts by mass of the total amount of the components (A), (B), and (D). It is preferably 10 parts by mass. If it is 0.01 mass part or more, hardening will be enough, and if it is 10 mass parts or less, sufficient light transmittance will be obtained. From the above viewpoint, the amount is more preferably 0.05 to 7 parts by mass, and particularly preferably 0.1 to 5 parts by mass.

  3rd aspect WHEREIN: It is preferable that the usage-amount of (D) phenolic epoxy resin hardening | curing agent is the range whose equivalent ratio of phenolic hydroxyl group per epoxy group of an epoxy resin is 0.5-1.5. 0.8 to 1.2 is more preferable. If it is this range, hardening (crosslinking) of resin will become enough, a glass transition temperature will go up, and the moisture resistance of a hardening | curing agent can be improved.

  Said 3rd aspect WHEREIN: It is preferable that the compounding quantity of (E) hardening accelerator shall be 0-5.0 mass% with respect to the total amount with an epoxy resin and a phenol type epoxy resin hardening | curing agent, 0.05- It is more preferable to set it as 3.0 mass%, and it is more preferable to set it as 0.2-3.0 mass% further. When the blending amount of the curing accelerator is 5.0% by mass or less, the storage stability is improved and the pot life is sufficient.

  As a fourth embodiment of the resin composition for forming an upper clad layer used in the present invention, (A) a (meth) acrylic polymer having a reactive functional group and a weight average molecular weight of 100,000 or more, (B) urethane (meta ) Acrylate and (C) a radical polymerization initiator are preferably contained, and more preferably, the component (B) contains (meth) acrylate as described above.

  4th aspect WHEREIN: As for the usage-amount of the urethane (meth) acrylate of (B) component, 5-400 mass parts is preferable with respect to 100 mass parts of (A) (meth) acrylic polymer. If the blending amount is 5 parts by mass or more, the polymerization reaction of urethane (meth) acrylate is likely to occur, so that the peelability from the support substrate tends to be improved. If it is 400 parts by mass or less, the low elasticity of the (meth) acrylic polymer functions, and the flex resistance is improved without the film becoming brittle. Therefore, 10-70 mass parts is more preferable, and 20-50 mass parts is especially preferable.

  The said 4th aspect WHEREIN: As for the usage-amount of the (meth) acrylate of (B) component, 0-150 mass parts is preferable with respect to 100 mass parts of (A) (meth) acrylic polymer. By adding (meth) acrylate, the polymerization reaction tends to occur, so that the peelability from the supporting substrate tends to be improved. When the blending amount is 100 parts by mass or less, the low elasticity of the (meth) acrylic polymer functions, and the flex resistance is improved without the film becoming brittle. Therefore, 10-100 mass parts is more preferable, and 20-70 mass parts is especially preferable.

  4th aspect WHEREIN: The compounding quantity of the radical polymerization initiator of (C) component is 0.1-10 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component. preferable. If it is 0.1 parts by mass or more, curing is sufficient, and if it is 10 parts by mass or less, sufficient light transmittance is obtained. From the above viewpoint, the amount is more preferably 0.5 to 7 parts by mass, and particularly preferably 0.8 to 5 parts by mass.

  As a fifth aspect of the resin composition for forming an upper clad layer used in the present invention, (A) a (meth) acrylic polymer having a reactive functional group and having a weight average molecular weight of 100,000 or more, (B) fat It is a resin composition containing a cyclic epoxy resin and (C) a cationic polymerization initiator, and (B) the alicyclic epoxy resin preferably contains 50% by mass or more of a liquid at room temperature.

  5th aspect WHEREIN: It is preferable that the compounding quantity of the (meth) acrylic polymer of (A) component is 10-85 mass% with respect to the total amount of (A) component and (B) component. If it is 10% by mass or more, the strength and flexibility of the cured product of the resin composition for optical materials is sufficient, and if it is 85% by mass or less, it is easily entangled by the component (B) during curing. The developer resistance is not insufficient. From the above viewpoint, the blending amount of the component (A) is more preferably 20 to 80% by mass, and particularly preferably 25 to 75% by mass.

The said 5th aspect WHEREIN: It is preferable that the compounding quantity of the alicyclic epoxy resin of (B) component is 15-90 mass% with respect to the total amount of (A) component and (B) component. If it is 15% by mass or more, it is easy to entangle the (A) component (meth) acrylic polymer, and the developer resistance is not insufficient. If it is 90% by mass or less, the cured film Film strength and flexibility are sufficient. From the above viewpoint, the blending amount of the component (B) is more preferably 20 to 80% by mass, and particularly preferably 25 to 75% by mass.
In addition, as the (B) alicyclic epoxy resin, from the viewpoint of transparency and compatibility with the (meth) acrylic polymer, the alicyclic epoxy resin that is liquid at room temperature in the component (B) is preferably 50% by mass. More preferably, the content is 70% by mass or more, more preferably 85% by mass or more, and the component (B) is particularly preferably made of a liquid alicyclic epoxy resin at room temperature.

  5th aspect WHEREIN: The compounding quantity of the cationic polymerization initiator of (C) component shall be 0.01-10 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component. preferable. If it is 0.01 mass part or more, hardening will be enough, and if it is 10 mass parts or less, sufficient light transmittance will be obtained. From the above viewpoint, the amount is more preferably 0.05 to 7 parts by mass, and particularly preferably 0.1 to 5 parts by mass.

As a sixth embodiment of the resin composition for forming an upper clad layer used in the present invention, it is preferable to contain (A) a modified polyamideimide, (B) an epoxy resin, and (D) an epoxy resin curing agent.
As the component (A), the aforementioned silicone-modified polyamideimide and / or butadiene-modified polyamideimide are preferable. Moreover, it is preferable that (B) component contains the above-mentioned bisphenol type epoxy resin and / or phenol novolac type epoxy resin. Further, as the component (D), it is preferable to use the above-described phenol-based epoxy resin curing agent and / or amine-based epoxy resin curing agent.

  6th aspect WHEREIN: As for the usage-amount of (B) epoxy resin, 5-250 mass parts is preferable with respect to 100 mass parts of (A) modified polyamideimide. When it is within this range, it is possible to ensure the elastic modulus and flowability during molding, and to obtain sufficient handleability at high temperatures. (B) As for the usage-amount of an epoxy resin, 10-100 mass parts is more preferable, and 20-50 mass parts is especially preferable.

  In the sixth aspect, the epoxy resin curing agent (D) is effective because it is excellent in impact resistance under high temperature and high pressure when combined with an epoxy resin. (D) There is no restriction | limiting in particular as an epoxy resin hardening | curing agent, A phenol type hardening | curing agent, an amine type hardening | curing agent, etc. are mentioned, Although these are the above-mentioned details, Among these, transparency and a modified polyamideimide From the standpoint of compatibility, the phenolic curing agent is preferably a bifunctional phenol such as hydroquinone, resorcinol, catechol, bisphenol A, or bisphenol F; The amine curing agent is preferably an aliphatic amine, an alicyclic amine, or an aromatic amine.

  6th aspect WHEREIN: It is preferable that the usage-amount of (D) component is the range whose equivalent ratio per epoxy group of an epoxy resin is 0.5-1.5, 0.8-1.2 It is more preferable that If it is this range, hardening (crosslinking) of resin will become enough, a glass transition temperature will go up, and the moisture resistance of a hardening | curing agent can be improved.

In the sixth aspect, (F) bismaleimide can be further added to the upper clad layer forming resin composition as necessary.
The bismaleimide used in the present invention is not particularly limited as long as it contains two or more maleimide groups in the molecule. For example, 1-methyl-2,4-bismaleimidebenzene, N, N ′ -M-phenylene bismaleimide, N, N'-p-phenylene bismaleimide, N, N'-m-toluylene bismaleimide, N, N'-4,4'-biphenylene bismaleimide, N, N'-4 , 4 ′-[3,3′-dimethylbiphenylene] bismaleimide, N, N′-4,4 ′-[3,3′-dimethyldiphenylmethane] bismaleimide, N, N′-4,4 ′-[3 , 3′-diethyldiphenylmethane] bismaleimide, N, N′-4,4′-diphenylmethane bismaleimide, N, N′-4,4′-diphenylpropane bismaleimide, N, N′-4,4′-diphenyl ether Sumerimide, N, N′-3,3′-diphenylsulfone bismaleimide, N, N′-4,4′-diphenylsulfone bismaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [3-tert-butyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [3-s-butyl-4- (4-maleimidophenoxy) phenyl] propane, 1-bis [4- (4-maleimidophenoxy) phenyl] decane, 1,1-bis [2-methyl-4- (4-maleimidophenoxy) -5-t-butylphenyl] -2-methylpropane, 4, 4′-cyclohexylidene-bis [1- (4-maleimidophenoxy) -2- (1,1-dimethylethyl) benzene], 4,4′-methylene-bis [1- (4-male Imidophenoxy) -2,6-bis (1,1-dimethylethyl) benzene], 4,4′-methylene-bis [1- (4-maleimidophenoxy) -2,6-di-s-butylbenzene], 4,4′-cyclohexylidene-bis [1- (4-maleimidophenoxy) -2-cyclohexylbenzene, 4,4′-methylene-bis [1- (maleimidophenoxy) -2-nonylbenzene], 4,4 '-(1-methylethylidene) -bis [1- (maleimidophenoxy) -2,6-bis (1,1-dimethylethyl) benzene], 4,4'-(2-ethylhexylidene) -bis [ 1- (maleimidophenoxy) -benzene], 4,4 ′-(1-methylheptylidene) -bis [1- (maleimidophenoxy) -benzene], 4,4′-cyclohexylidene-bis [1- ( Maleimidophenoxy) -3-methylbenzene], 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [4- (4-maleimidophenoxy) phenyl] hexafluoropropane, 2, 2-bis [3-methyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [3-methyl-4- (4-maleimidophenoxy) phenyl] hexafluoropropane, 2,2-bis [ 3,5-dimethyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [3,5-dimethyl-4- (4-maleimidophenoxy) phenyl] hexafluoropropane, 2,2-bis [ 3-ethyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [3-ethyl-4- (4-maleimi Phenoxy) phenyl] hexafluoropropane, bis [3-methyl-4- (4-maleimidophenoxy) phenyl] methane, bis [3,5-dimethyl-4- (4-maleimidophenoxy) phenyl] methane, bis [3- Ethyl-4- (4-maleimidophenoxy) phenyl] methane, 3,8-bis [4- (4-maleimidophenoxy) phenyl] -tricyclo- [5.2.1.02,6] decane, 4,8- Bis [4- (4-maleimidophenoxy) phenyl] -tricyclo- [5.2.1.02,6] decane, 3,9-bis [4- (4-maleimidophenoxy) phenyl] -tricyclo- [5. 2.1.02,6] decane, 4,9-bis [4- (4-maleimidophenoxy) phenyl] -tricyclo- [5.2.1.02,6] decane, , 8-bis [4- (4-maleimidophenoxy) phenyl] menthane, 1,8-bis [3-methyl-4- (4-maleimidophenoxy) phenyl] menthane, 1,8-bis [3,5-dimethyl -4- (4-maleimidophenoxy) phenyl] menthane and the like. Among these, from the viewpoint of transparency and compatibility with the modified polyamideimide, N, N′-m-phenylenebismaleimide or the like having a low aromatic conjugation is preferable. These compounds can be used alone or in combination of two or more.

  The blending amount of (F) bismaleimide is preferably 0 to 100 parts by mass, more preferably 5 to 95 parts by mass with respect to 100 parts by mass of (A) modified polyamideimide. More preferably, it is 90 mass parts. When the amount of bismaleimide is 100 parts by mass or less, the film characteristics are good.

As a seventh embodiment of the resin composition for forming an upper clad layer used in the present invention, (A) acrylonitrile-butadiene rubber, (B) (meth) acrylate, (C) a radical polymerization initiator, and (D ) It preferably contains an epoxy resin curing agent.
(A) As mentioned above, the acrylonitrile-butadiene rubber is preferably a carboxyl group-containing acrylonitrile-butadiene rubber containing 0.5 to 6% by mass of a carboxyl group-containing repeating unit.

  As the (meth) acrylate of the component (B), any of monofunctional, bifunctional, or trifunctional or more polyfunctional ones can be used as described above. The amount of (B) (meth) acrylate used is preferably 5 to 100 parts by mass with respect to 100 parts by mass of (A) acrylonitrile-butadiene rubber. If the blending amount is 5 parts by mass or more, the polymerization reaction of (meth) acrylate is likely to occur, so that the peelability from the support substrate tends to be improved. If it is 100 parts by mass or less, the low elasticity of acrylonitrile-butadiene rubber functions, and the flex resistance is improved without the film becoming brittle, which is preferable. Therefore, 10-70 mass parts is more preferable, and 20-50 mass parts is especially preferable.

Moreover, it is also a preferable aspect that (B) component contains an epoxy resin in addition to (meth) acrylate. The epoxy resin preferably contains a bisphenol type epoxy resin and / or a phenol novolac type epoxy resin.
(B) When adding an epoxy resin as a component, it is preferable to contain (D) an epoxy resin hardening | curing agent. Specifically, a phenol-based epoxy resin curing agent is preferable, and it is particularly preferable that at least one of a phenol novolak resin, a bisphenol A novolak resin, and a cresol novolak type epoxy resin is included.

Next, the resin composition for forming the lower cladding layer will be described in detail. The resin composition for forming the lower cladding layer is not particularly limited as long as it satisfies the above-described requirements for the rate of change in film thickness, and those described as the resin composition for forming the upper cladding layer can be used. .
Further, the resin composition for forming the upper cladding layer and the resin composition for forming the lower cladding layer may be the same or different, but usually the rate of change in the film thickness required for the resin composition for forming the lower cladding layer, and the upper In order to control the bending durability required for the resin composition for forming a cladding layer, it is advantageous to use different materials.

  Specifically, the resin composition for forming a lower clad layer contains (a) a base polymer, (b) a photopolymerizable compound, and (c) a photopolymerization initiator, and changes in the above-described film thickness It is selected within the range that satisfies the rate requirement. That is, when the core layer is exposed and developed, it is selected according to the type of solvent used in the development process.

  (A) Examples of the base polymer include phenoxy resins, epoxy resins, (meth) acrylic resins, polycarbonate resins, polyarylate resins, polyether amides, polyether imides, polyether sulfones, and derivatives thereof. These base polymers may be used alone or in combination of two or more. Of the base polymers exemplified above, from the viewpoint of high heat resistance, the main chain preferably has an aromatic skeleton, and particularly preferably a phenoxy resin. From the viewpoint of three-dimensional crosslinking and improving heat resistance, an epoxy resin, particularly an epoxy resin that is solid at room temperature is preferable. Further, compatibility with the photopolymerizable compound (B) described in detail later is important for ensuring the transparency of the resin film for forming the cladding layer. From this point, the phenoxy resin and the (meth) acrylic resin are used. Resins are preferred. Here, (meth) acrylic resin means acrylic resin and methacrylic resin.

  Among phenoxy resins, those containing bisphenol A or a bisphenol A type epoxy compound or a derivative thereof, and bisphenol F or a bisphenol F type epoxy compound or a derivative thereof as a constituent unit of a copolymer component are heat resistant, adhesive and soluble. It is preferable because of its excellent properties. Preferred examples of the bisphenol A or bisphenol A type epoxy compound include tetrabromobisphenol A and tetrabromobisphenol A type epoxy compounds. Moreover, as a derivative of bisphenol F or a bisphenol F-type epoxy compound, tetrabromobisphenol F, a tetrabromobisphenol F-type epoxy compound, etc. are mentioned suitably. Specific examples of the bisphenol A / bisphenol F copolymer type phenoxy resin include “Phenotote YP-70” (trade name) manufactured by Toto Kasei Co., Ltd.

  Examples of the epoxy resin that is solid at room temperature include, for example, “Epototo YD-7020, Epototo YD-7019, Epototo YD-7007” (all trade names) manufactured by Toto Chemical Co., Ltd., and “Epicoat 1010” manufactured by Japan Epoxy Resins Co., Ltd. Bisphenol A type epoxy resin such as “Epicoat 1009, Epicoat 1008” (both trade names).

  (A) The molecular weight of the base polymer is preferably 5,000 or more in terms of number average molecular weight, more preferably 10,000 or more, and particularly preferably 30,000 or more, from the viewpoint of film formability. Although there is no restriction | limiting in particular about the upper limit of a number average molecular weight, It is preferable that it is 1,000,000 or less from the viewpoint of compatibility with (b) photo polysynthesis compound and exposure developability, Furthermore, 500,000. Hereinafter, it is particularly preferably 200,000 or less.

  (A) It is preferable that the compounding quantity of a base polymer shall be 10-80 mass% with respect to the total amount of (a) component and (b) component. When the blending amount is 10% by mass or more, there is an advantage that it is easy to form a thick film of about 50 to 500 μm necessary for forming an optical waveguide. On the other hand, when the blending amount is 80% by mass or less, a photocuring reaction occurs. Progresses sufficiently. From the above viewpoint, the blending amount of the (a) base polymer is more preferably 20 to 70% by mass.

Next, (b) the photopolymerizable compound is not particularly limited as long as it is polymerized by irradiation with light such as ultraviolet rays. Examples thereof include compounds having a saturated group.
Specific examples of compounds having two or more epoxy groups in the molecule include bisphenol A type epoxy resins, tetrabromobisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, naphthalene type epoxy resins, etc. Bifunctional aromatic glycidyl ether; phenol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene-phenol type epoxy resin, tetraphenylol ethane type epoxy resin, etc. polyfunctional aromatic glycidyl ether; polyethylene glycol type epoxy resin, Bifunctional aliphatic glycidyl ether such as polypropylene glycol type epoxy resin, neopentyl glycol type epoxy resin, hexanediol type epoxy resin; hydrogenated bisphenol A type epoxy Bifunctional alicyclic glycidyl ethers such as resins; polyfunctional aliphatic glycidyl ethers such as trimethylolpropane type epoxy resins, sorbitol type epoxy resins and glycerin type epoxy resins; bifunctional aromatic glycidyl esters such as phthalic acid diglycidyl esters; Bifunctional alicyclic glycidyl esters such as tetrahydrophthalic acid diglycidyl ester and hexahydrophthalic acid diglycidyl ester; bifunctional aromatic glycidyl amines such as N, N-diglycidylaniline and N, N-diglycidyltrifluoromethylaniline N, N, N ′, N′-tetraglycidyl-4,4-diaminodiphenylmethane, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, O-triglycidyl-p-aminophenol Polyfunctional aromatic glycidyla such as Min; Bifunctional alicyclic epoxy resin such as alicyclic diepoxy acetal, alicyclic diepoxy adipate, alicyclic diepoxy carboxylate, vinylcyclohexene dioxide; Bifunctional heterocyclic epoxy resin such as diglycidyl hydantoin A polyfunctional heterocyclic epoxy resin such as triglycidyl isocyanurate; a bifunctional or polyfunctional silicon-containing epoxy resin such as an organopolysiloxane type epoxy resin;

  These compounds having two or more epoxy groups in the molecule usually have a molecular weight of about 100 to 2,000, more preferably about 150 to 1,000, and those that are liquid at room temperature are suitably used. Moreover, these compounds can be used individually or in combination of 2 or more types, Furthermore, it can also be used in combination with another photopolymerizable compound.

  Specific examples of the compound having an ethylenically unsaturated group in the molecule include (meth) acrylate, vinylidene halide, vinyl ether, vinyl pyridine, vinyl phenol, etc. Of these, transparency and heat resistance are included. From the viewpoint, (meth) acrylate is preferable, and any of monofunctional, bifunctional, trifunctional or higher can be used. Specifically, it is the same as described above.

  The blending amount of the (b) photopolymerizable compound is preferably 20 to 90% by mass with respect to the total amount of the component (a) and the component (b). When the blending amount is 20% by mass or more, the base polymer can be easily entangled and cured, and when it is 90% by mass or less, a sufficiently thick clad layer can be easily formed. it can. From the above viewpoint, it is more preferable that the blending amount of the (b) photopolymerizable compound is 30 to 80% by mass.

  Next, the photopolymerization initiator of the component (c) is not particularly limited. For example, as an initiator of an epoxy compound, an aryldiazonium salt such as p-methoxybenzenediazonium hexafluorophosphate; diphenyliodonium hexafluorophosphonium salt, diphenyliodonium Diaryl iodonium salts such as hexafluoroantimonate salt; triphenylsulfonium hexafluorophosphonium salt, triphenylsulfonium hexafluoroantimonate salt, diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate salt, diphenyl-4-thiophenoxyphenylsulfonium Hexafluoroantimonate salt, diphenyl-4-thiophenoxyphenylsulfonium pentafluorohydroxyantimonate salt A triarylsulfonium salt; a triphenylselenonium hexafluorophosphonium salt, a triphenylselenonium borofluoride salt, a triarylselenonium salt such as a triphenylselenonium hexafluoroantimonate salt; a dimethylphenacylsulfonium hexafluoroantimonate salt; Dialkylphenazylsulfonium salts such as diethylphenacylsulfonium hexafluoroantimonate salt; dialkyl-4-hydroxyphenylsulfonium salts such as 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate salt, 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate salt Α-hydroxymethylbenzoin sulfonate ester, N-hydroxyimide sulfonate, α-sulfonyloxy Ketones, such as sulfonic acid esters, such as β- sulfo Niro carboxymethyl ketone.

Moreover, as an initiator of the compound having an ethylenically unsaturated group in the molecule, benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4 '-Diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2,2-dimethoxy-1,2 -Diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy- 2-Methyl-1-propan-1-one, 1,2-methyl-1- [4- (methylthio) phenyl] -2-morph Aromatic ketones such as linopropan-1-one; 2-ethylanthraquinone, phenanthrenequinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2 , 3-Diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, quinones such as 2,3-dimethylanthraquinone Benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether; benzoin compounds such as benzoin, methyl benzoin and ethyl benzoin; benzyl such as benzyl dimethyl ketal; Derivatives; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, etc. 2,4,5-triarylimidazole dimer; bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide Phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Niruakurijin, 1,7-bis (9,9'-acridinyl) heptane and the like acridine derivatives; N- phenylglycine, N- phenylglycine derivatives, coumarin-based compounds. In addition, in the 2,4,5-triarylimidazole dimer, the aryl group substituents of two 2,4,5-triarylimidazoles may give the same and symmetric compounds, or differently asymmetric Such compounds may be provided. Moreover, you may combine a thioxanthone type compound and a tertiary amine compound like the combination of diethyl thioxanthone and dimethylaminobenzoic acid. Of these compounds, aromatic ketones and phosphine oxides are preferred from the viewpoint of improving the transparency of the core layer and the cladding layer.
These (c) photopolymerization initiators can be used alone or in combination of two or more.

  (C) It is preferable that the compounding quantity of a photoinitiator shall be 0.1-10 mass parts with respect to 100 mass parts of total amounts of (a) component and (b) component. If it is 0.1 parts by mass or more, the photosensitivity is sufficient, while if it is 10 parts by mass or less, only the surface of the optical waveguide is selectively cured, the curing does not become insufficient, It is preferable that the propagation loss does not increase due to absorption of the photopolymerization initiator itself. From the above viewpoint, the amount of (c) the photopolymerization initiator is more preferably 1 to 5 parts by mass.

  In addition, if necessary, in the lower clad layer forming resin, an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, a filler, etc. These so-called additives may be added at a rate that does not adversely affect the effects of the present invention.

  In the present invention, it is also preferable that the resin for forming the lower cladding layer uses (a) acrylonitrile-butadiene rubber as the base polymer. By containing acrylonitrile-butadiene rubber, in addition to solvent resistance, bending resistance can be imparted to the optical waveguide.

  Next, the resin composition for forming a core layer can be a resin composition that is designed so that the core layer has a higher refractive index than that of the cladding layer and can form a core pattern with actinic rays. Things are preferred. Specifically, it is preferable to use the same resin composition as that used in the lower clad layer forming resin. That is, it is a resin composition containing the components (a), (b) and (c) and optionally containing the optional components.

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

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

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

Hereinafter, the resin film for forming a clad layer (upper clad and lower clad) of the present invention will be described.
The resin film for forming a clad layer of the present invention can be easily produced by applying the resin composition for forming a clad layer to a suitable support film. Moreover, when the said resin composition for clad layer formation is diluted with the said organic solvent, it can manufacture by apply | coating a resin composition to a support film and removing an organic solvent.

The support film is not particularly limited, and examples thereof include: polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene; polycarbonates, polyamides, polyimides, polyamideimides, polyetherimides, polyether sulfides, polysulphides. Examples include ether sulfone, polyether ketone, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, and liquid crystal polymer. Among these, from the viewpoint of flexibility and toughness, it may be polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyamide, polyimide, polyamideimide, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone. preferable.
In addition, you may use the film in which the mold release process was given with the silicone type compound, the fluorine-containing compound, etc. from a viewpoint of peelability improvement with a resin layer as needed.

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

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

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

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

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

  The clad layer-forming resin film thus obtained can be easily stored, for example, by being rolled up. Moreover, a roll-shaped film can be cut out into a suitable size and stored in a sheet shape.

Next, the resin film for core part formation can be manufactured using the resin composition for core part formation by the same method as the resin film for clad layer formation. The support film used in the production process of the core portion forming resin film is not particularly limited as long as it can transmit the actinic ray for exposure used for core pattern formation. For example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate. Polyester such as phthalate; Polyolefin such as polyethylene and polypropylene; Polycarbonate, Polyamide, Polyimide, Polyamideimide, Polyetherimide, Polyethersulfide, Polyethersulfone, Polyetherketone, Polyphenyleneether, Polyphenylenesulfide, Polyarylate, Polysulfone, Liquid crystal polymer Etc.
Among these, the polyester and the polyolefin are preferable from the viewpoints of the transmittance of exposure actinic rays, flexibility, and toughness. Furthermore, it is more preferable to use a highly transparent support film from the viewpoint of improving the transmittance of exposure actinic rays and reducing the roughness of the side wall of the core pattern. Examples of such highly transparent support films include Cosmo Shine A1517 and Cosmo Shine A4100 manufactured by Toyobo Co., Ltd.
In addition, you may use the film in which the mold release process was given with the silicone type compound, the fluorine-containing compound, etc. from a viewpoint of peelability improvement with a resin layer as needed.

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

  The core part-forming resin film produced by applying the core part-forming resin composition onto the support film is attached to the resin layer as necessary, and the support film, the resin layer, and the protective film. It is good also as a 3 layer structure which consists of.

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

Next, a method for forming an optical waveguide using the resin composition for an optical waveguide, the resin varnish for forming an optical waveguide, and the film for forming an optical waveguide of the present invention as a clad material and a core material will be described in detail.
The optical waveguide manufacturing method of the present invention includes a step of forming an optical waveguide forming resin layer as a lower cladding layer on a substrate, a step of forming an optical waveguide forming resin layer as a core layer, and a desired core pattern. A step of exposing, a step of developing with a developer of an organic solvent or an alkaline aqueous solution after the exposure to form a core portion, and a step of forming a resin layer for forming an optical waveguide as an upper clad layer.

  The substrate used for the optical waveguide of the present invention is not particularly limited, but various materials can be used depending on the application, for example, silicon wafer, glass epoxy substrate, plastic substrate, metal substrate, substrate with metal layer, etc. And a rigid wiring board, a polyimide substrate, a plastic film such as a PET film, a plastic film with a resin layer, a plastic film with a metal layer, and the like, and a flexible wiring board, copper foil, and glass. These substrates may be treated with an adhesion-imparting agent such as a coupling agent, or may be subjected to UV-ozone treatment or plasma treatment in order to improve adhesion to the resin composition. Various adhesives may be used. It is also possible to impart releasability to the base material and peel off the base material after manufacturing the optical waveguide.

The method for forming the optical waveguide forming resin layer as the lower clad layer, core layer, and upper clad layer is not particularly limited. For example, the optical waveguide forming resin composition of the present invention or the optical waveguide forming resin is used. Examples of the varnish include spin coating, dip coating, spraying, bar coating, roll coating, curtain coating, gravure coating, screen coating, and inkjet coating.
When using a resin varnish for forming an optical waveguide, a drying step may be added after forming the resin layer as necessary. Examples of the drying method include heat drying and vacuum drying. Moreover, you may use these together as needed.

In addition, as another method for forming the photosensitive resin layer for forming an optical waveguide, a method of forming by a laminating method using the resin film for forming an optical waveguide of the present invention can be mentioned. It is preferable to laminate under reduced pressure from the viewpoint of adhesion and followability.
Among these, from the viewpoint that an optical waveguide manufacturing process with excellent productivity can be provided, a method of manufacturing by a lamination method using a resin film for forming an optical waveguide is preferable.

The method of forming by the laminating method is not particularly limited, and examples thereof include a method of laminating by pressure bonding while heating using a roll laminator or a flat plate laminator. In the present invention, the flat plate type laminator refers to a laminator in which a laminated material is sandwiched between a pair of flat plates and pressed by pressing the flat plate. For example, a vacuum pressurizing laminator can be suitably used. The heating temperature here is preferably 20 to 130 ° C., and the pressure bonding pressure is preferably 0.1 to 1.0 MPa, but these conditions are not particularly limited.
In addition, before lamination by a vacuum pressure laminator, a photosensitive resin film for forming a lower clad layer may be temporarily pasted on a substrate using a roll laminator. Here, from the viewpoint of improving adhesion and followability, it is preferable to perform temporary bonding while pressure bonding. When pressure bonding, it may be performed while heating using a laminator having a heat roll. The laminating temperature is preferably 20 to 130 ° C. If it is 20 degreeC or more, the adhesiveness of the photosensitive resin film for lower clad layer formation and a board | substrate will improve, and if it is 130 degrees C or less, a resin layer does not flow too much at the time of roll lamination, and the required film thickness is can get. From the above viewpoint, it is more preferable that it is 40-100 degreeC. The pressure is preferably 0.2 to 0.9 MPa and the laminating speed is preferably 0.1 to 3 m / min, but these conditions are not particularly limited.

Hereinafter, a method for manufacturing an optical waveguide will be described more specifically with reference to FIG.
First, as a first step, an optical waveguide forming resin composition for forming a lower clad layer or an optical waveguide forming resin varnish using the same is applied onto the substrate by a spin coating method or the like, A film for forming an optical waveguide for forming a cladding layer is laminated by lamination or the like. When the cover film is present in the resin film for forming an optical waveguide for forming the lower clad layer, it is preferable to laminate after removing the cover film or while removing it.
The lower clad layer forming resin composition layer applied or laminated on the substrate is photocured to form a lower clad layer (see FIG. 1A). If the base film is present in the resin film for forming an optical waveguide for forming the lower cladding layer, it may be removed thereafter.
The irradiation amount of the actinic ray when forming the lower clad layer is preferably 0.1 to 5 J / cm ² , but these conditions are not particularly limited. Moreover, when actinic rays permeate | transmit a base material, in order to make it harden | cure efficiently, the double-sided exposure machine which can irradiate actinic rays simultaneously from both surfaces can be used. Moreover, you may irradiate actinic light, heating.
In addition, as a process after photocuring, you may perform a 50-200 degreeC heat processing as needed.

  The thickness of the lower cladding layer is desirably 1 to 100 μm. When the thickness is 1 μm or more, light can be sufficiently confined, and when it is 100 μm or less, film formation is easy. From the above viewpoint, the thickness of the lower clad is preferably in the range of 3 to 80 μm, particularly preferably 5 to 50 μm.

Next, as a second step, an optical waveguide forming resin composition for forming a core portion on the lower cladding layer, or an optical waveguide forming resin varnish using the same in the same manner as in the first step, or An optical waveguide forming resin film is applied or laminated to form a core portion forming resin layer (see FIG. 1B). Here, the resin composition for forming an optical waveguide for forming the core portion is designed to have a higher refractive index than the resin composition for forming an optical waveguide for forming the lower clad layer, and the core pattern can be formed by actinic rays. It is preferably made of a resin composition for forming an optical waveguide. Moreover, when using the film for optical waveguide formation, it is preferable to laminate | stack using a roll laminator.
Although the film thickness of the core portion forming resin layer can be changed depending on the use of the optical waveguide, generally, about 20 to 80 μm is preferable in the case of a multimode waveguide.

Subsequently, as a third step, the core portion (core pattern) is exposed. The method for exposing the core pattern is not particularly limited. For example, the core layer-forming resin layer formed on the lower cladding layer is preferably a negative or so called artwork under deoxidation conditions such as in a nitrogen atmosphere. Examples include a method of irradiating actinic light in an image form through a positive mask pattern (photomask), a method of directly irradiating an active light on an image without passing through a photomask using direct laser drawing (FIG. 1C). reference). Examples of the active light source include known light sources that effectively emit ultraviolet light, such as carbon arc lamps, mercury vapor arc lamps, ultrahigh pressure mercury lamps, high pressure mercury lamps, xenon lamps, and metal halide lamps. In addition, a light source that effectively emits visible light, such as a photographic flood bulb or a solar lamp, can also be used. When the resin film for forming an optical waveguide is used for forming the core layer, it may be exposed after peeling the base film or may be exposed through the base film.
It is preferable that the irradiation amount of the actinic ray at the time of exposing a core pattern is 0.01-10 J / cm < ² >. If it is 0.01 J / cm ² or more, the curing reaction will proceed sufficiently, and the core pattern will not be washed away by the development process described later, and if it is 10 J / cm ² or less, the core pattern will become thick due to excessive exposure. This is preferable because a fine core pattern can be formed. From the above viewpoints, 0.05 to 5 J / cm ² is more preferable, and 0.1 to 3 J / cm ² is particularly preferable.

When the resin film for forming an optical waveguide for forming the core portion is used, the exposure of the core pattern may be performed through the cover film or after the cover film is removed.
Further, after exposure, post-exposure heating may be performed as necessary from the viewpoint of improving the resolution and adhesion of the core pattern. The time from ultraviolet irradiation to post-exposure heating is preferably within 10 minutes. Within 10 minutes, active species generated by UV irradiation are not deactivated. The post-exposure heating temperature is preferably 40 to 160 ° C., and the time is preferably 30 seconds to 10 minutes.

Next, as a fourth step, a non-exposed portion is removed and developed by wet development, dry development, or the like, and a core pattern (core portion) is manufactured (see FIG. 1D). When the resin film for forming an optical waveguide for forming the core part is used for exposure through the base film, development is performed after removing the resin film. In the case of wet development, a developer corresponding to the composition of the resin film, such as an organic solvent, an alkaline aqueous solution, or an aqueous developer, is used. And developing by a known method such as a spin method. Moreover, you may use these image development methods together as needed.
As the developer, an organic solvent, an alkaline aqueous solution or the like that is safe and stable and has good operability is preferably used. Examples of the organic solvent developer include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, cyclohexanone, methyl isobutyl ketone, γ-butyrolactone, and ethyl acetate. , Butyl acetate, and various alcohols. These organic solvents may be added with water in the range of 1 to 20% by mass in order to prevent ignition.

Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium or potassium hydroxide; alkali carbonates such as lithium, sodium, potassium or ammonium carbonate or bicarbonate; potassium phosphate, phosphoric acid Examples include alkali metal phosphates such as sodium; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate.
Examples of the alkaline aqueous solution used for development include a dilute solution of 0.1 to 5% by mass of sodium carbonate, a dilute solution of 0.1 to 5% by mass of potassium carbonate, and a dilute solution of 0.1 to 5% by mass of sodium hydroxide. Preferred examples include a solution and a dilute solution of 0.1 to 5% by mass sodium tetraborate.
Moreover, it is preferable to make pH of the alkaline aqueous solution used for image development into the range of 9-11, and the temperature is adjusted according to the developability of the layer of the photosensitive resin composition. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like may be mixed.

Examples of the aqueous developer include those composed of water or an aqueous alkali solution and one or more organic solvents. Examples of the alkaline substance include borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1,3-diaminopropanol-2-morpholine and the like can be mentioned.
The pH of the developer is preferably as low as possible within a range where the resist can be sufficiently developed, preferably pH 8-12, more preferably pH 9-10.

Examples of the organic solvent include triacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono And butyl ether. These are used alone or in combination of two or more.
The concentration of the organic solvent is usually preferably 2 to 90% by mass, and the temperature can be adjusted according to the developability. Further, a small amount of a surfactant, an antifoaming agent and the like can be mixed in the aqueous developer.

As the treatment after development, the core pattern may be further cured and used by heating at about 60 to 250 ° C. or exposure at about 0.1 to 1000 mJ / cm ² as necessary.

  Next, as a fifth step, after the core pattern is formed, the resin composition for an optical waveguide having a refractive index lower than that of the core, or a resin varnish using the same, or a film by coating or laminating method, An upper cladding layer is formed (see FIG. 1E). The formation method is the same as the formation method of the lower cladding layer. When using a film for forming an optical waveguide, it is preferable to laminate using a roll laminator or a vacuum pressure laminator.

EXAMPLES The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Physical property measurement method (1-1) Preparation of cured film for tensile test, bending durability test, total light transmittance and haze measurement Surface release treatment of resin varnish for forming upper clad layer obtained in each example and comparative example The PET film (Teijin DuPont Films Co., Ltd. A53, thickness 25 μm) was coated on the mold release surface using a coating machine (Hirano Techseed Co., Ltd. Multicoater TM-MC) and dried at 100 ° C. for 20 minutes. Subsequently, a surface release treatment PET film (A31 manufactured by Teijin DuPont Films, Inc., thickness 25 μm) was applied as a protective film to obtain an upper clad layer forming resin film. The thickness of the resin layer was adjusted to 110 μm for the tensile test, bending durability test, total light transmittance and haze measurement, and 50 μm for the cured film for refractive index measurement.

(1-2) Tensile test The tensile test (distance between grips 50 mm) of the cured film (width 10 mm, length 70 mm) obtained in the above (1) was used as a tensile tester (RTM-100 manufactured by Orientec Co., Ltd.). ) At a temperature of 25 ° C. and a pulling speed of 500 mm / min in accordance with JIS K 7127.
Initial elastic modulus (tensile modulus), yield strength (tensile yield strength), maximum strength (tensile strength), yield elongation (tensile yield elongation), elongation at break (tensile elongation at break) are calculated in accordance with JIS K 7127. Obtained by law.

(1-3) Bending durability test The bending durability test of the cured film (width 5 mm, length 100 mm) obtained in the above (1) was performed using a bending durability tester (manufactured by Daisho Electronics Co., Ltd.) with a bending angle of 0. A bending endurance test was performed under the conditions of ˜180 °, a bending radius of 2 mm, and a bending speed of 2 times / second.

(1-4) Measurement of total light transmittance and haze The total light transmittance and haze of the cured film obtained in the above (1) were measured for color separation and turbidity measuring instrument (COH 400 manufactured by Nippon Denshoku Kogyo Co., Ltd.). ).

(1-5) Change rate of film thickness (%)
The resin composition for forming the lower clad layer is applied to a PET substrate having a thickness of 25 μm so that the thickness after drying becomes 20 μm, and after exposure to 4000 mJ / cm ^{2 at} a wavelength of 365 nm, the resin composition for 10 minutes at 80 ° C. The sample for a measurement was produced by drying. The thickness T ₁ of the coating film of the measurement sample was measured. Subsequently, the film thickness T ₂ after the sample was immersed in a solvent used for patterning the core layer at 23 ° C. for 120 seconds was measured, and the change rate of the film thickness 100 × (T ₂ −T ₁ ) / T ₁ (%) was determined.

Evaluation Method (2-1) Propagation Loss of Optical Waveguide Propagation loss of optical waveguides manufactured in each of the examples and comparative examples was obtained by using a VCSEL of 850 nm (FLS-300-01-VCL, manufactured by EXFO) and a light receiving sensor as a light source. (Advantest Co., Ltd., Q82214), cut back method (measurement waveguide length 5, 3, 2 cm, incident fiber; GI-50.525 multimode fiber (NA = 0.20), outgoing fiber; SI- 114/125 (NA = 0.22)).

(2-2) Flexural resistance of optical waveguide The optical waveguide manufactured in each example was subjected to a flexural test of the optical waveguide in the same manner as the above (1-3) flexural durability test. evaluated.

Example 1
(1) Preparation of resin varnish for forming lower clad layer (a) 35 parts by mass of “Phenotote YP-70” manufactured by Tohto Kasei Co., Ltd. as a base polymer, (b) Shin-Nakamura Chemical Co., Ltd. as a photopolymerizable compound ( Co., Ltd. “KRM-2110” 63 parts by mass, and (c) 2 parts by mass of “SP-170” manufactured by Tokyo Chemical Industry Co., Ltd. as a polymerization initiator, and 40 parts by mass of ethyl cellosolve as a solvent. In addition, a resin varnish for forming a lower clad layer was prepared.

(2) Preparation of resin varnish for core layer formation (a) 20 parts by mass of “Phenotote YP-70” manufactured by Toto Kasei Co., Ltd. as a base polymer, and (b) Shin-Nakamura Chemical Co., Ltd. as a photopolymerizable compound ) "A-BPEF" 39 parts by mass and ADEKA "EA-1020" 39 parts by mass, and (c) 1 part by mass of "Irgacure 819" manufactured by Ciba Specialty Chemicals and Ciba as radical polymerization initiator -1 part by mass of "Irgacure 2959" manufactured by Specialty Chemicals, and 40 parts by mass of ethyl cellosolve as a solvent were added thereto to prepare a resin varnish for forming a core layer.

(3) Preparation of resin varnish for forming upper clad layer (A) “HTR-860P-3” (weight average molecular weight) manufactured by Nagase ChemteX Corporation as a (meth) acrylic polymer having a reactive functional group which is a binder resin 800,000, EEW; 4,809 g / eq) 60 parts by mass, (B) 20 parts by mass of “AH-600” manufactured by Kyoeisha Chemical Co., Ltd. as urethane (meth) acrylate, and Kyoeisha Chemical Co., Ltd. as (meth) acrylate ) "TMP-A" 20 parts by mass, (C) 1 part by mass of Ciba Specialty Chemicals "Irgacure 819" and Ciba Specialty Chemicals "Irgacure 2959" as a radical polymerization initiator Then, 40 parts by mass of ethyl cellosolve was added as a solvent to prepare an upper clad layer forming resin varnish.

(4) Preparation of core layer forming resin film and cladding layer forming resin film PET film (Toyobo Co., Ltd., “Cosmo Shine A1517”, thickness 16 μm) and applicator (Yoshimi Seiki Co., Ltd. “YBA-4”) )) Is applied to the resin varnish for forming the clad layer (for forming the upper clad layer and for forming the lower clad layer) and the resin varnish for forming the core layer (cladding layer forming resin film; adhesive treatment surface in the winding) Use, resin film for core layer formation; use of untreated surface outside winding), 80 ° C., 10 minutes, then 100 ° C., 10 minutes to dry the solvent, core layer formation resin film, upper clad layer formation resin film And the resin film for lower clad layer formation was produced. The film thickness at this time can be arbitrarily adjusted between 5 and 100 μm by adjusting the gap of the applicator. In this example, the film thickness after curing is 40 μm for the core layer and the lower cladding layer. The thickness was adjusted to 20 μm and the upper cladding layer to 70 μm.

(5) Production of optical waveguide The resin film for forming the lower cladding layer is irradiated with 1000 mJ / cm ^{2 of} ultraviolet rays (wavelength 365 nm) with an ultraviolet exposure machine (Oak Manufacturing Co., Ltd. “EXM-1172”) to form the lower cladding layer. (Refer to FIG. 1A.) Next, a vacuum pressure laminator (“MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.) was used on the clad layer, and the pressure was set to 0.00. The core layer-forming resin film was laminated under the conditions of 4 MPa, a temperature of 70 ° C., and a pressing time of 30 seconds (see FIG. 1B). Subsequently, after irradiation with 1000 mJ / cm ^{2 of} ultraviolet light (wavelength 365 nm) through the photomask (negative type) having a width of 40 μm (see FIG. 1 (c)), N, N-dimethylacetamide and The core pattern was developed with a 3 to 7 (mass ratio) mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) (see FIG. 1 (d)). Methanol and water were used for washing the developer. Subsequently, the resin film for upper clad formation was laminated on the same lamination conditions, the ultraviolet irradiation and the heat processing were performed at 160 degreeC, and the flexible optical waveguide was manufactured (refer FIG.1 (e)).
When the refractive index of the core layer and the clad layer was measured with a prism coupler (Model 2010) manufactured by Metricon, the core layer was 1.584, the lower clad layer was 1.537, and the upper clad layer was 1 at a wavelength of 850 nm. 4895. The propagation loss of the optical waveguide was 0.08 dB / cm, and when the optical waveguide was tested for flexibility, it did not break even after 1 million cycles.

Examples 2 and 3
In Example 1, an optical waveguide was produced in the same manner as in Example 1 except that the component (B) of the resin varnish for forming the upper clad layer was the one shown in Table 1.
The results of evaluation in the same manner as in Example 1 are shown in Table 1.

Examples 4 and 5
In Example 2, an optical waveguide was manufactured in the same manner as in Example 2 except that the resin varnish for forming the lower cladding layer was the one shown in Table 1.
The results of evaluation in the same manner as in Example 1 are shown in Table 1.

Comparative Example 1
When an optical waveguide was manufactured in the same manner as in Example 1 using the lower clad composed of the components shown in Table 1, the lower clad was greatly swollen during the exposure / development process of the core pattern. Changed and could not proceed to the next step.

Comparative Example 2
When an optical waveguide was manufactured in the same manner as in Example 1 using the lower clad composed of the components shown in Table 1, the lower clad swelled greatly during the core pattern exposure / development process. Changed and could not proceed to the next step.

Comparative Example 3
As components of the upper clad, 90 parts by mass of “Phenotote YP-70” manufactured by Toto Kasei Co., Ltd., 10 parts by mass of “KRM-2110” manufactured by ADEKA Co., Ltd., “SP-170” 2 manufactured by ADEKA Co., Ltd. When the bending durability test of the upper clad film was carried out using the mass part, it was destroyed in 10,000 times or less.

* 1 HTR-860P-3; (meth) acrylic polymer having a reactive functional group, manufactured by Nagase ChemteX Corporation (weight average molecular weight; 800,000, EEW; 4,809 g / eq)
* 2 Phenototoy YP-70; Bisphenol A / bisphenol F copolymerized phenoxy resin, manufactured by Tohto Kasei Co., Ltd. * 3 AH-600; Urethane (meth) acrylate, manufactured by Kyoeisha Chemical Co., Ltd. * 4 792SH8K; Urethane (meta ) Acrylate, manufactured by Hitachi Chemical Co., Ltd. * 5 UA160-TM; urethane (meth) acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. * 6 TMP-A; (meth) acrylate, manufactured by Kyoeisha Chemical Co., Ltd. * 7 KRM Epoxy resin, manufactured by Adeka Co., Ltd. * 8 Irgacure 819; manufactured by Ciba Specialty Chemicals * 9 Irgacure 2959; manufactured by Ciba Specialty Chemicals * 10 SP-170; manufactured by Tokyo Chemical Industry Co., Ltd. * 11 A- BPEF: aromatic diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. * 12 EA-102 Aromatic epoxy acrylate, manufactured by ADEKA Co., Ltd. * 13 DN631; carboxyl group-containing acrylonitrile-butadiene rubber, manufactured by Nippon Zeon Co., Ltd. * 14 DN101L; high nitrile acrylonitrile-butadiene rubber, manufactured by Nippon Zeon Co., Ltd. * 15 YX8000; alicyclic epoxy resin, manufactured by Japan Epoxy Resin Co., Ltd. * 16 A-9300; ethoxylated isocyanuric acid triacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. * 17 LF4871; bisphenol A type phenolic resin, Dainippon Ink * 18 2PZ-CN manufactured by Chemical Industry Co., Ltd .; 1-cyanoethyl-2-phenylimidazole, manufactured by Shikoku Chemicals Co., Ltd.

  Since the optical waveguide of the present invention has good bending resistance and erosion of the lower cladding layer due to solvent development is suppressed, the optical characteristics are good.

DESCRIPTION OF SYMBOLS 1; Substrate 2; Lower clad layer 3; Core part forming resin layer 4; Base film 5; Photomask 6; Core pattern (core part)
7; upper clad layer 8; base film

Claims (25)

  An optical waveguide in which a lower clad layer, a patterned core layer, and an upper clad layer are laminated in this order on a substrate, and the thickness after drying the resin composition for forming the lower clad layer is 20 μm. The film thickness change rate before and after immersing the film in the core layer patterning solvent for 120 seconds is 50% or less, and the upper clad layer forming resin composition is the upper clad layer forming resin composition. An optical waveguide characterized in that a cured film having a thickness of 110 μm obtained by curing is a tensile yield elongation at 25 ° C. of 5.5 to 30%. 2. The optical waveguide according to claim 1, wherein the relative refractive index difference between the upper cladding layer and the lower cladding layer is 5% or less.   The optical waveguide according to claim 1, wherein a relative refractive index difference between the core pattern and the lower cladding layer and a relative refractive index difference between the core pattern and the upper cladding layer are 1 to 10%, respectively.   The optical waveguide according to claim 1, wherein a cured film having a thickness of 110 μm obtained by curing the resin composition for forming an upper clad layer has a tensile elastic modulus at 25 ° C. of 1 to 2000 MPa.   The optical waveguide according to any one of claims 1 to 4, wherein a cured film having a thickness of 110 µm formed by curing the resin composition for forming an upper cladding layer has a total light transmittance of 50% or more.   The resin for forming the upper cladding layer contains at least one selected from the group consisting of (meth) acrylic polymers, modified polyamideimides, and acrylonitrile-butadiene rubbers as the component (A), and polymerizable as the component (B). The compound according to any one of claims 1 to 5, comprising a compound, optionally containing a polymerization initiator as component (C), and optionally containing an epoxy resin curing agent as component (D). Optical waveguide. Wherein component (A) has a reactive functional group, and a weight average molecular weight of 100,000 or more (meth) acrylic polymer, the component (B) is an epoxy resin, and the component (D) The optical waveguide according to claim 6, which is a phenol-based epoxy resin curing agent. It has a component (A) is a reactive functional group, and a weight average molecular weight of 100,000 or more (meth) acrylic polymer, the component (B) is an epoxy resin and photoactive monomer, the ( The optical waveguide according to claim 6, wherein the component (C) is a photobase generator, and the component (D) is a phenolic epoxy resin curing agent. Wherein a component (A) is a reactive functional group, and a weight average molecular weight of 100,000 or more (meth) acrylic polymer, a said component (B) (meth) acrylates and epoxy resins, the ( The optical waveguide according to claim 6, wherein component (C) is a radical polymerization initiator and component (D) is a phenolic epoxy resin curing agent. Wherein component (A) has a reactive functional group, and a weight average molecular weight of 100,000 or more (meth) acrylic polymer, the component (B) is a urethane (meth) acrylate, and the (C The optical waveguide according to claim 6, wherein the component is a radical polymerization initiator. Wherein component (A) has a reactive functional group, and a weight average molecular weight of 100,000 or more (meth) acrylic polymer, the component (B) is an alicyclic epoxy resin, wherein the (C) The optical waveguide according to claim 6, wherein the component is a resin composition containing a cationic polymerization initiator, and the (B) alicyclic epoxy resin contains 50% by mass or more of a liquid at room temperature. Wherein component (A) is a modified polyamide-imide, the component (B) is an epoxy resin, and an optical waveguide according to claim 6 wherein component (D) is an epoxy resin curing agent. The optical waveguide according to claim 12, wherein the (A) modified polyamideimide is a silicone-modified polyamideimide or a butadiene-modified polyamideimide. The optical waveguide according to claim 12 or 13, wherein the (B) epoxy resin includes a bisphenol type epoxy resin or a phenol novolac type epoxy resin. The optical waveguide according to claim 12, wherein the (D) epoxy resin curing agent is a phenol-based epoxy resin curing agent or an amine-based epoxy resin curing agent.   Furthermore, the optical waveguide in any one of Claims 12-15 containing a bismaleimide as (F) component. Wherein component (A) is acrylonitrile - a butadiene rubber, component (B) is a (meth) acrylate, and an optical waveguide according to claim 6 wherein component (C) is a radical polymerization initiator. The optical waveguide according to claim 17, wherein the (A) acrylonitrile-butadiene rubber is a carboxyl group-containing acrylonitrile-butadiene rubber containing 0.5 to 6 mass% of a carboxyl group-containing repeating unit. The component (B) is (meth) acrylate and an epoxy resin, and an optical waveguide according to claim 17 or 18 wherein the component (D) is a phenol-based epoxy resin curing agent. The optical waveguide according to claim 19, wherein the (B) epoxy resin includes a bisphenol type epoxy resin or a phenol novolac type epoxy resin. The optical waveguide according to claim 19 or 20, wherein the (D) phenolic epoxy resin curing agent includes at least one of a phenol novolac resin, a bisphenol A novolac resin, and a cresol novolac type epoxy resin. The said core pattern formation resin composition and the said lower clad layer formation resin composition contain (a) base polymer, (b) photopolymerizable compound, and (c) photoinitiator, respectively. 21. The optical waveguide according to any one of 21. The (a) base polymer is at least one selected from phenoxy resin, epoxy resin, (meth) acrylic resin, polycarbonate resin, polyarylate resin, polyetheramide, polyetherimide, polyethersulfone, and derivatives thereof. The optical waveguide according to claim 22. The optical waveguide according to claim 22 or 23, wherein the (b) photopolymerizable compound is a compound having two or more epoxy groups in the molecule or a compound having an ethylenically unsaturated group in the molecule. The resin for forming a lower clad layer contains (a) acrylonitrile-butadiene rubber as a base polymer, (b) a polymerizable compound, and (c) a photopolymerization initiator. The optical waveguide according to any one of the above.

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