Optical component bonding composition, cured product, and optical fiber array

Abstract

Provided is an optical component bonding composition which yields a cured product exhibiting excellent yellowing resistance. Also provided are: a cured product having a good appearance due to excellent yellowing resistance; and an optical fiber array comprising the cured product.　The optical component bonding composition contains a siloxane compound (A) having a reactive functional group, a polymerization initiator (B), a filler (C), and an antioxidant (D).

Description

Optical component adhesive composition, cured product, and optical fiber array

[0001] The present invention relates to an adhesive composition for optical components, a cured product, and an optical fiber array.

[0002] Silicon photonics has attracted attention as a means of responding to the recent increase in communication speeds and the rapid increase in communication volume in information and communications. Silicon photonics is a technology for integrating elements such as optical waveguides, optical switches, optical modulators, and photodetectors on a silicon substrate, and by integrating optical devices and electronic circuits into optical integrated circuits, it is possible to realize small, highly functional optical devices.

[0003] In silicon photonics, solder mounting may require multiple reflow processes at 200 to 260°C, so optical adhesives for silicon photonics are required to have optical properties (e.g., low refractive index and high transmittance) and reflow resistance.

[0004] Generally, known techniques for lowering the refractive index include a method for lowering the glass transition temperature of a composition for bonding optical components, a method for lowering the crosslink density of a polymer, etc. For example, Patent Document 1 describes a low refractive index adhesive containing an acrylic matrix resin and porous hollow resin particles.

[0005] JP 2011-037978 A

[0006] However, the composition of Patent Document 1 has a problem in that the cured product has low resistance to yellowing. That is, the cured product yellows over time and the yellowing rate is rapid, resulting in a problem in appearance.

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical component bonding composition that gives a cured product with excellent yellowing resistance. Another object of the present invention is to provide a cured product that has excellent yellowing resistance and therefore a good appearance, and an optical fiber array including the cured product.

[0008] As a result of extensive research into achieving the above object, the present inventors have found that the above problems can be solved by using a composition having a specific structure. The present invention was completed based on these findings.

[0009] That is, the present invention provides a composition for bonding optical parts, which comprises a siloxane compound (A) having a reactive functional group, a polymerization initiator (B), a filler (C), and an antioxidant (D).

[0010] The composition preferably contains, as the antioxidant (D), at least one selected from the group consisting of phenol-based antioxidants and phosphite-based antioxidants.

[0011] The composition preferably contains, as the siloxane compound (A) having a reactive functional group, a cyclic siloxane compound (A1) having a reactive functional group and a chain siloxane compound (A2) having a reactive functional group.

[0012] The cyclic siloxane compound (A1) having a reactive functional group preferably has two or more groups containing a cationically polymerizable group as the reactive functional group.

[0013] The cyclic siloxane compound (A1) having a reactive functional group preferably has two or four groups containing an epoxy group as the reactive functional group.

[0014] The chain siloxane compound (A2) having a reactive functional group preferably has two or more groups containing a cationically polymerizable group as the reactive functional group.

[0015] The chain siloxane compound (A2) having a reactive functional group preferably has two or more groups containing an alicyclic epoxy group as the reactive functional group.

[0016] The composition preferably contains the cyclic siloxane compound (A1) having a reactive functional group and the chain siloxane compound (A2) having a reactive functional group (total amount) of 5 to 90 mass %.

[0017] The mass ratio of the cyclic siloxane compound (A1) having a reactive functional group to the chain siloxane compound (A2) having a reactive functional group is preferably 90:10 to 5:95.

[0018] The composition preferably has a retention rate (%) of 72.0% or more, as calculated by the following formula. The following transmittances are values ​​measured at 25°C. Retention rate (%) = Transmittance (%) of cured product (after heat treatment) at a wavelength of 425 nm / Transmittance (%) of cured product (initial) at a wavelength of 425 nm × 100 Cured product (initial): Cured product 1 hour after completion of curing of the composition Cured product (after heat treatment): Cured product after the cured product (initial) was reflowed five times at 260°C in a nitrogen atmosphere, and then exposed to and heat-treated at 200°C in an air atmosphere for 4 hours.

[0019] The content of the filler (C) in the composition is preferably 5 to 90 mass %.

[0020] The composition is preferably used to fix an optical fiber to a groove formed in an optical waveguide element.

[0021] The composition is preferably used for optically coupling an optical fiber to an optical waveguide element.

[0022] The composition is preferably used to simultaneously fix an optical fiber to a groove formed in an optical waveguide element and optically couple the optical fiber to the optical waveguide element.

[0023] The present invention also provides a cured product of the above composition.

[0024] The present invention also provides an optical fiber array comprising the above composition, an optical fiber, and an optical waveguide element, wherein the optical fiber is optically coupled to the optical waveguide element via the composition.

[0025] The optical component bonding composition of the present invention has excellent yellowing resistance when cured, and an optical fiber array including the cured composition has a good appearance due to the excellent yellowing resistance of the cured product.

[0026] 3 is an exploded perspective view of the optical waveguide module, an enlarged view of the vicinity of the connection portion, a side view showing a state in which an optical fiber is fixed to an optical waveguide element, and a cross-sectional view taken along the line AA in FIG.

[0027] [Optical Component Adhesion Composition] The optical component adhesive composition of the present invention contains a siloxane compound (A) having a reactive functional group, a polymerization initiator (B), a filler (C), and an antioxidant (D). The composition preferably contains, as the antioxidant (D), at least one selected from the group consisting of a phenolic antioxidant and a phosphite antioxidant. The composition preferably contains, as the siloxane compound (A) having a reactive functional group, a cyclic siloxane compound (A1) having a reactive functional group and a linear siloxane compound (A2) having a reactive functional group. Hereinafter, the siloxane compound (A) having a reactive functional group, the cyclic siloxane compound (A1) having a reactive functional group, and the linear siloxane compound (A2) having a reactive functional group may be referred to as the siloxane compound (A), the siloxane compound (A1), and the siloxane compound (A2), respectively.

[0028] (Siloxane Compound (A)) The siloxane compound (A) is a compound having a reactive functional group and a siloxane bond (—Si—O—). The number of Si—O units contained in the molecule of the siloxane compound (A) is not particularly limited, but is, for example, preferably 1 to 100, more preferably 2 to 50, and even more preferably 3 to 30. The reactive functional group is not particularly limited as long as it is a group that is reactive with the components in the composition. Examples include groups containing a cationically polymerizable group such as an epoxy group-containing group, an oxetanyl group-containing group, or a vinyl ether group-containing group, a vinyl group-containing group, or a (meth)acryloyl group-containing group. Here, the epoxy group is a group having a three-membered ring (oxirane ring) consisting of two carbon atoms and one oxygen atom, and is also called an ethylene oxide group. The siloxane compound (A) may have one reactive functional group or two or more (for example, preferably 2 to 30, more preferably 3 to 20). In the composition, the siloxane compound (A) may be used alone or in combination of two or more kinds.

[0029] By including the siloxane compound (A), the optical properties (for example, low refractive index and high transmittance) and reflow resistance of the cured product tend to be excellent. Furthermore, the composition preferably contains, as the siloxane compound (A), a cyclic siloxane compound (A1) having a reactive functional group and / or a linear siloxane compound (A2) having a reactive functional group, and more preferably contains both the cyclic siloxane compound (A1) having a reactive functional group and the linear siloxane compound (A2) having a reactive functional group. In this case, the cured product of the composition tends to have better optical properties and reflow resistance.

[0030] Cyclic siloxane compound (A1) having a reactive functional group The siloxane compound (A1) is a compound having a reactive functional group and a cyclic siloxane skeleton. The cyclic siloxane skeleton refers to a skeleton (siloxane ring) formed in a ring shape by siloxane bonds (-Si-O-). The number of Si-O units in the siloxane ring is not particularly limited, but is preferably 2 to 15, more preferably 3 to 10, even more preferably 3 to 8, and particularly preferably 3 to 6. The number of Si-O units is equal to the number of silicon atoms forming the siloxane ring.

[0031] The siloxane compound (A1) preferably has a group containing a cationically polymerizable group as a reactive functional group. When the siloxane compound (A1) is contained as the siloxane compound (A) in the above composition, the combination of the siloxane ring and the group containing a cationically polymerizable group tends to result in a cured product exhibiting high heat resistance and reduced cure shrinkage. Examples of the group containing a cationically polymerizable group include a group containing an epoxy group, a group containing an oxetanyl group, and a group containing a vinyl ether group. From the viewpoint of the heat resistance of the cured product, the reactive functional group possessed by the siloxane compound (A1) is preferably a group containing a cationically polymerizable group that does not have an aromatic ring.

[0032] From the viewpoints of optical properties, heat resistance, and storage stability of the composition, the group containing a cationically polymerizable group in the siloxane compound (A1) is preferably a group containing an epoxy group. The epoxy group may be an alicyclic epoxy group or a non-alicyclic epoxy group. That is, the group containing a cationically polymerizable group may be a group containing an alicyclic epoxy group or a group containing a non-alicyclic epoxy group.

[0033] The alicyclic epoxy group is a group having a cycloalkene oxide structure. The cycloalkene oxide structure is a structure having an aliphatic ring and an epoxy group that constitutes the aliphatic ring and is composed of two adjacent carbon atoms and oxygen atoms. The cycloalkene oxide structure can be obtained, for example, by epoxidizing a cycloalkene with an oxidizing agent such as a peroxide. In the siloxane compound (A2), examples of the alicyclic skeleton of the alicyclic epoxy group include aliphatic rings having 2 to 12 carbon atoms, such as a cyclobutane skeleton, cyclopentane skeleton, cyclohexane skeleton, cycloheptane skeleton, and cyclooctane skeleton, with a cyclohexane skeleton being preferred.

[0034] Examples of groups containing an alicyclic epoxy group include groups in which one or more hydrogen atoms of an alkyl group have been substituted with an alicyclic epoxy group, such as a 2,3-epoxycyclohexylethyl group and a 3,4-epoxycyclohexylethyl group. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 6, and more preferably 2 to 4.

[0035] The non-alicyclic epoxy group is an epoxy group other than the above-mentioned alicyclic epoxy groups. Examples of groups containing a non-alicyclic epoxy group include a glycidyl group and a glycidoxyalkyl group. Examples of the glycidoxyalkyl group include a glycidoxymethyl group, a glycidoxyethyl group, a glycidoxypropyl group (e.g., a 3-glycidoxypropyl group), and a glycidoxybutyl group (e.g., a 4-glycidoxybutyl group), with the 3-glycidoxypropyl group being preferred.

[0036] The number of reactive functional groups in the siloxane compound (A1) is not particularly limited as long as it is one or more. From the viewpoint of curability, the number is preferably two or more, more preferably 2 to 10, even more preferably 2 to 6, particularly preferably 2 to 4, and particularly preferably 2 or 4.

[0037] In the siloxane compound (A1), the epoxy group may be bonded directly to the siloxane ring or may be bonded via a linking group. The linking group may be a divalent group, for example, an alkylene group [—(CH ２ )n- (n is preferably an integer of 1 or more, more preferably 1 to 10, and even more preferably 2 to 5)], an ether bond (—O—), an ester bond (—COO—), and a group containing two or more of these. The proximity of the epoxy group and the siloxane ring tends to result in a dense cured product when the composition is cured, and the cured product tends to have excellent heat resistance (for example, reflow resistance). Therefore, when the epoxy group is bonded to the siloxane ring via a linking group, the number of atoms present between the epoxy group and the siloxane ring, which are derived from the linking group, is preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less.

[0038] As the siloxane compound (A1), for example, a siloxane compound represented by the following formula (1) can be used.

[0039]

[0040] In the formula, n represents an integer of 3 to 10. １ and R ２ are the same or different and represent a group containing an epoxy group or a hydrocarbon group, provided that n R １ and R ２ At least one of R is a group containing an epoxy group. １ and R ２ The hydrocarbon group in is not particularly limited, but is preferably an alkyl group, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms.

[0041] The above n is not particularly limited as long as it is an integer of 3 to 10, but is preferably an integer of 4 to 6. The above epoxy group-containing group may be a group containing an alicyclic epoxy group or a group containing a non-alicyclic epoxy group.

[0042] Examples of the siloxane compound (A1) include 2,4-di[2-(3-{oxabicyclo[4.1.0]heptyl})ethyl]-2,4,6,6,8,8-hexamethyl-cyclotetrasiloxane, 4,8-di[2-(3-{oxabicyclo[4.1.0]heptyl})ethyl]-2,2,4,6,6,8-hexamethyl-cyclotetrasiloxane, 2,4-di[2-(3-{oxabicyclo[4.1.0]heptyl})ethyl]-6,8-dipropyl-2,4,6,8-tetramethyl-cyclotetrasiloxane, 4,8-di[2-(3-{oxabicyclo[4.1.0]heptyl} ) ethyl]-2,6-dipropyl-2,4,6,8-tetramethyl-cyclotetrasiloxane, 2,4,8-tri[2-(3-{oxabicyclo[4.1.0]heptyl})ethyl]-2,4,6,6,8-pentamethyl-cyclotetrasiloxane, 2,4,8-tri[2-(3-{oxabicyclo[4.1.0]heptyl})ethyl]-6-propyl-2,4,6,8-tetramethyl-cyclotetrasiloxane, and 2,4,6,8-tetra[2-(3-{oxabicyclo[4.1.0]heptyl})ethyl]-2,4,6,8-tetramethyl-cyclotetrasiloxane.

[0043] Commercially available siloxane compounds (A1) include, for example, KR-470 (number of epoxy groups: 4), X-40-2670 (number of epoxy groups: 4), and X-40-2678 (number of epoxy groups: 2) (all manufactured by Shin-Etsu Chemical Co., Ltd.), which are cyclic siloxane compounds having an alicyclic epoxy group, i.e., a glycidyl group, and X-40-2701 (number of epoxy groups: 4) and X-40-2728 (number of epoxy groups: 2) (all manufactured by Shin-Etsu Chemical Co., Ltd.), which are cyclic siloxane compounds having a non-alicyclic epoxy group, i.e., a glycidyl group; and ADEKA RESIN EP-3400L (number of epoxy groups: 4) (manufactured by ADEKA Corporation), which is a cyclic dimethylsiloxane compound having four 3-glycidoxypropyl groups in the molecule.

[0044] The epoxy equivalent (g / mol) of the siloxane compound (A1) is not particularly limited, but from the viewpoint of reactivity, it is preferably from 50 to 1,000, more preferably from 100 to 500, and even more preferably from 150 to 400. In this specification, the epoxy equivalent can be measured in accordance with JIS K7236.

[0045] The weight-average molecular weight of the siloxane compound (A1) is not particularly limited, but is preferably 200 to 3,000, more preferably 300 to 2,000, and even more preferably 400 to 1,000. When the weight-average molecular weight of the siloxane compound (A1) is within the above range, the viscosity of the composition becomes appropriate, improving workability. In this specification, the weight-average molecular weight can be calculated by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene.

[0046] The siloxane compound (A1) is preferably a liquid at room temperature (25°C), but may also be a solid. From the viewpoint of workability, the viscosity of the siloxane compound (A1) at 25°C is preferably 10 to 30,000 mPa·s. In this specification, viscosity can be measured in accordance with Japanese Industrial Standard JIS K6833. Specifically, it can be determined by measuring using an E-type viscometer at a rotation speed of 10 rpm. There are no particular limitations on the equipment, rotor, or measurement range used.

[0047] Chain siloxane compound (A2) having a reactive functional group The siloxane compound (A2) is a compound having a reactive functional group and a chain siloxane skeleton. The chain siloxane skeleton refers to a skeleton (siloxane chain) in which siloxane bonds (-Si-O-) are bonded in a chain shape. The number of Si-O units in the siloxane chain is not particularly limited, but is preferably 2 to 50, more preferably 3 to 40, even more preferably 5 to 30, and particularly preferably 10 to 20. The number of Si-O units is equal to the number of silicon atoms forming the siloxane chain.

[0048] The siloxane compound (A2) preferably has a group containing a cationically polymerizable group as a reactive functional group. When the siloxane compound (A2) is contained as the siloxane compound (A) in the above composition, the combination of the siloxane chain and the group containing a cationically polymerizable group tends to result in a low refractive index of the resulting cured product and reduced cure shrinkage. Examples of the group containing a cationically polymerizable group include a group containing an epoxy group, a group containing an oxetanyl group, and a group containing a vinyl ether group. From the viewpoint of the heat resistance of the cured product, the reactive functional group of the siloxane compound (A2) is preferably a group containing a cationically polymerizable group that does not have an aromatic ring.

[0049] From the viewpoints of optical properties, heat resistance, and adhesiveness, the group containing a cationically polymerizable group in the siloxane compound (A2) is preferably a group containing an epoxy group. The epoxy group may be an alicyclic epoxy group or a non-alicyclic epoxy group. That is, the group containing a cationically polymerizable group may be a group containing an alicyclic epoxy group or a group containing a non-alicyclic epoxy group.

[0050] In the siloxane compound (A2), examples of the alicyclic skeleton of the alicyclic epoxy group include aliphatic rings having 2 to 12 carbon atoms, such as a cyclobutane skeleton, cyclopentane skeleton, cyclohexane skeleton, cycloheptane skeleton, and cyclooctane skeleton, and preferably an aliphatic ring having 4 to 8 carbon atoms, such as a cyclohexane skeleton.

[0051] Examples of groups containing an alicyclic epoxy group include groups in which one or more hydrogen atoms of an alkyl group have been substituted with an alicyclic epoxy group, such as a 2,3-epoxycyclohexylethyl group and a 3,4-epoxycyclohexylethyl group. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 6, and more preferably 2 to 4.

[0052] The non-alicyclic epoxy group is an epoxy group other than the above-mentioned alicyclic epoxy groups. Examples of groups containing a non-alicyclic epoxy group include a glycidyl group and a glycidoxyalkyl group. Examples of the glycidoxyalkyl group include a glycidoxymethyl group, a glycidoxyethyl group, a glycidoxypropyl group (e.g., a 3-glycidoxypropyl group), and a glycidoxybutyl group (e.g., a 4-glycidoxybutyl group), with the 3-glycidoxypropyl group being preferred.

[0053] The number of reactive functional groups in the siloxane compound (A2) is not particularly limited as long as it is one or more. From the viewpoint of curability, the number is preferably two or more, more preferably 2 to 10, even more preferably 2 to 6, particularly preferably 2 to 4, and particularly preferably 2.

[0054] In the siloxane compound (A2), the epoxy group may be bonded directly to the siloxane chain or may be bonded via a linking group. The linking group may be a divalent group, for example, an alkylene group [—(CH ２ )n- (n is preferably an integer of 1 or more, more preferably 1 to 10, and even more preferably 2 to 5)], an ether bond (—O—), an ester bond (—COO—), and groups containing two or more of these. The proximity of the epoxy group and the siloxane chain tends to result in a dense cured product when the composition is cured, and the cured product tends to have excellent heat resistance (reflow resistance). Therefore, when the epoxy group is bonded to the siloxane chain via a linking group, the number of atoms present between the epoxy group and the siloxane chain, which are derived from the linking group, is preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less.

[0055] Examples of the siloxane compound (A2) include linear siloxane compounds having an epoxy group-containing group at the molecular terminal. A linear siloxane compound having an epoxy group-containing group at the molecular terminal means a compound having an alicyclic epoxy group-containing group or a non-alicyclic epoxy group-containing group at the terminal of the main chain formed by a siloxane bond. The siloxane compound (A2) may have an epoxy group-containing group at at least one terminal of the main chain, but preferably has an epoxy group-containing group at all terminals of the main chain (or both terminals of the main chain if the main chain is not branched). The siloxane compound (A2) may have an epoxy group on a side chain in addition to the terminal of the main chain, but preferably has an epoxy group-containing group only at the terminal of the main chain.

[0056] As the siloxane compound (A2), for example, a compound represented by the following formula (2) can be used.

[0057] In the formula, R ３ and R ８ are the same or different and represent a group containing an epoxy group. ４ , R ５ , R ６ , R ７ , R ９ , R １１ , and R １２ are the same or different and represent a hydrocarbon group. １０ are the same or different and represent a group containing a hydrocarbon group or an epoxy group. m is an integer of 0 to 3000. n is an integer of 0 to 3000. R ４ ~R ７ and R ９ ~R １２ The hydrocarbon group in is not particularly limited, but is preferably, for example, an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms.

[0058] R ３ , R ８ , and R １０The epoxy group-containing group in the formula (I) may be a group containing an alicyclic epoxy group or a group containing a non-alicyclic epoxy group. Examples of the alicyclic epoxy group-containing group include groups in which one or more hydrogen atoms in an alkyl group have been substituted with an alicyclic epoxy group, such as a 2,3-epoxycyclohexylethyl group or a 3,4-epoxycyclohexylethyl group. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 6, and more preferably 2 to 4. Examples of the non-alicyclic epoxy group-containing group include a glycidyl group and a glycidoxyalkyl group. Examples of the glycidoxyalkyl group include a glycidoxymethyl group, a glycidoxyethyl group, a glycidoxypropyl group (e.g., a 3-glycidoxypropyl group), and a glycidoxybutyl group (e.g., a 4-glycidoxybutyl group), with the 3-glycidoxypropyl group being preferred. m is preferably an integer from 0 to 1000, more preferably an integer from 0 to 500, even more preferably an integer from 0 to 100, even more preferably an integer from 0 to 30, and even more preferably an integer from 0 to 15. n is preferably an integer from 0 to 300, more preferably an integer from 0 to 100, even more preferably an integer from 0 to 30, even more preferably an integer from 0 to 15, and even more preferably an integer from 0 to 5.

[0059] The siloxane compound (A2) is not particularly limited, but for example, a chain siloxane compound having a group containing an alicyclic epoxy group or a group containing a non-alicyclic epoxy group at the molecular terminal is preferably used. Commercially available siloxane compounds (A2) include, but are not limited to, X-22-169B, X-22-169AS, and X-40-2669 having alicyclic epoxy groups at both ends; X-22-163, KF-105, X-22-163A, X-22-163B, and X-22-163C having epoxy groups (non-alicyclic epoxy groups) at both ends; X-22-2046 and KF-102 having alicyclic epoxy groups in the side chain; X-22-343, KF-101, KF-1001, and X-22-2000 having epoxy groups (non-alicyclic epoxy groups) in the side chain; and X-22-9002 having epoxy groups (non-alicyclic epoxy groups) at both ends and in the side chain (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0060] The epoxy equivalent (g / mol) of the siloxane compound (A2) is not particularly limited, but is preferably 100 to 4,000, more preferably 120 to 2,000, and even more preferably 150 to 1,000, from the viewpoint of reactivity.

[0061] The weight-average molecular weight of the siloxane compound (A2) is not particularly limited, but is, for example, preferably 200 to 10,000, more preferably 200 to 8,000, and even more preferably 400 to 6,000. When the weight-average molecular weight of the siloxane compound (A2) is within the above range, the viscosity of the composition becomes appropriate, and workability is improved.

[0062] The siloxane compound (A2) is preferably a liquid at room temperature (25° C.), but may also be a solid. From the viewpoint of workability, the viscosity of the siloxane compound (A2) at 25° C. is preferably 1 to 500 mPa s, more preferably 2 to 300 mPa s, and even more preferably 5 to 100 mPa s.

[0063] The content of the siloxane compound (A) relative to the optical component bonding composition (100% by mass) is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more. Furthermore, it is preferably 90% by mass or less, more preferably 75% by mass or less, even more preferably 60% by mass or less, even more preferably 50% by mass or less, and particularly preferably 45% by mass or less. The content of the siloxane compound (A) relative to the optical component bonding composition (100% by mass) is preferably 5 to 90% by mass, more preferably 10 to 75% by mass, more preferably 20 to 60% by mass, even more preferably 30 to 50% by mass, and particularly preferably 30 to 45% by mass. When the content of the siloxane compound (A) is within the above range, optical properties and reflow resistance tend to be improved. Furthermore, yellowing resistance tends to be improved.

[0064] The content (total amount) of the siloxane compound (A1) and the siloxane compound (A2) relative to the optical component bonding composition (100% by mass) is not particularly limited, but is, for example, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more. Furthermore, for example, it is preferably 90% by mass or less, more preferably 75% by mass or less, even more preferably 60% by mass or less, even more preferably 50% by mass or less, and particularly preferably 45% by mass or less. The content (total amount) of the siloxane compound (A1) and the siloxane compound (A2) relative to the optical component bonding composition (100% by mass) is, for example, preferably 5 to 90% by mass, more preferably 10 to 75% by mass, more preferably 20 to 60% by mass, even more preferably 30 to 50% by mass, and particularly preferably 30 to 45% by mass. When the content (total amount) of the siloxane compound (A1) and the siloxane compound (A2) is within the above range, the optical properties and reflow resistance tend to be improved, and the yellowing resistance also tends to be improved.

[0065] The content of the siloxane compound (A1) relative to the optical component bonding composition (100% by mass) is not particularly limited, but is preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 6% by mass or more, even more preferably 8% by mass or more, and particularly preferably 10% by mass or more. Furthermore, it is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and particularly preferably 15% by mass or less. The content of the siloxane compound (A1) relative to the optical component bonding composition (100% by mass) is preferably 2 to 30% by mass, more preferably 4 to 25% by mass, even more preferably 6 to 20% by mass, even more preferably 8 to 15% by mass, and particularly preferably 10 to 15% by mass. When the content of the siloxane compound (A1) is within the above range, heat resistance tends to be improved.

[0066] The content of the siloxane compound (A2) relative to the optical component bonding composition (100% by mass) is not particularly limited, but is preferably 4% by mass or more, more preferably 8% by mass or more, even more preferably 12% by mass or more, even more preferably 16% by mass or more, and particularly preferably 20% by mass or more. Furthermore, it is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less. The content of the siloxane compound (A2) relative to the optical component bonding composition (100% by mass) is preferably 4 to 60% by mass, more preferably 8 to 50% by mass, even more preferably 12 to 40% by mass, even more preferably 16 to 30% by mass, and particularly preferably 20 to 30% by mass. When the content of the siloxane compound (A2) is within the above range, the refractive index of the cured product tends to decrease.

[0067] The mass ratio of the siloxane compound (A1) to the siloxane compound (A2) (siloxane compound (A1):siloxane compound (A2)) contained in the optical component bonding composition is not particularly limited, but is, for example, preferably 90:10 to 5:95, more preferably 70:30 to 15:85, even more preferably 60:40 to 20:80, even more preferably 50:50 to 25:75, still more preferably 45:55 to 30:70, and particularly preferably 40:60 to 30:70. When the mass ratio of the siloxane compound (A1) to the siloxane compound (A2) is within the above range, the optical properties and reflow resistance tend to be improved. Furthermore, the yellowing resistance tends to be improved.

[0068] Polymerization initiator (B) The polymerization initiator (B) is not particularly limited as long as it can initiate the polymerization reaction of the siloxane compound (A). As the polymerization initiator (B), an appropriate compound can be used depending on the type of reactive functional group possessed by the siloxane compound (A). In addition, in the above composition, one type of polymerization initiator (B) may be used alone, or two or more types may be used in combination.

[0069] The polymerization initiator (B) is not particularly limited, and examples thereof include photopolymerization initiators and thermal polymerization initiators, with photopolymerization initiators being preferred. The photopolymerization initiator is not particularly limited as long as it is a compound that generates an acid, a base, a radical, or the like and initiates curing of the siloxane compound (A) upon irradiation with active energy rays. Here, active energy rays include all light in the broad sense, such as radiation such as α-rays and β-rays, electromagnetic waves such as γ-rays and X-rays, electron beams (EB), ultraviolet rays of about 100 to 400 nm, and visible light of about 400 to 800 nm, with ultraviolet rays being preferred.

[0070] When the reactive functional group of the siloxane compound (A) is a group containing a cationic polymerizable group, it is preferable to use a photoacid generator as the photopolymerization initiator. The photoacid generator is a compound that generates an acid upon irradiation with active energy rays. The cationic polymerization of the siloxane compound (A) proceeds due to the catalytic effect of the acid generated from the photoacid generator. The photoacid generator is not particularly limited, and examples thereof include compounds that generate an acid upon irradiation, such as onium salts, halogen-containing compounds, diazomethane compounds, sulfone compounds, and sulfonic acid compounds.

[0071] From the viewpoint of achieving a low refractive index and high transparency, it is preferable to use an onium salt as the photoacid generator. The onium salt is a salt compound of an onium ion and an anion. The onium salt reacts with light to release a Lewis acid or a Bronsted acid (protonic acid).

[0072] The onium salt is not particularly limited, but is preferably at least one onium salt selected from the group consisting of onium gallates and onium borates, and preferably contains at least one cation selected from the group consisting of iodonium and sulfonium.

[0073] The onium gallate salt is not particularly limited, but examples thereof include onium salts represented by the following formula (3).

[0074]

[0075] In the formula, R １３ ~R １６are the same or different and represent a group having an alkyl group, an aryl group, or a heterocyclic ring having 1 to 18 carbon atoms. １３ ~R １６ At least one of the groups is an aryl group. The number of carbon atoms in the aryl group (excluding the number of carbon atoms in the substituent) is 6 to 14. The aryl group may have a substituent. E represents an element of Group 15 to Group 17 (IUPAC notation) with a valence of n. n is an integer of 1 to 3. R １７ is an organic group bonded to E. １７ The number of R is n+1, and (n+1) R １７ are the same or different, and two or more R １７ are directly connected to each other or are O-, -S-, -SO-, -SO ２ A ring structure containing the element E may be formed via -, -NH-, -CO-, -COO-, -CONH-, an alkylene group, or a phenylene group.

[0076] The onium gallate salt may contain an anion having a tetraphenyl gallate skeleton, and a hydrogen atom of a phenyl group of the tetraphenyl gallate skeleton may be substituted with at least one halogen atom selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The anion having a tetraphenyl gallate skeleton is preferably tetrakis(pentafluorophenyl)gallate. The onium gallate salt can be synthesized, for example, based on the method described in JP 2017-048325 A.

[0077] Examples of onium gallate salts include 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)gallate, triarylsulfonium tetrakis(pentafluorophenyl)gallate, diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)gallate, and 4-isopropylphenyl(p-tolyl)iodonium tetrakis(pentafluorophenyl)gallate.

[0078] The onium borate salt is not particularly limited, but examples thereof include onium salts represented by the following formula (4).

[0079]

[0080] In the formula, R １８ ~R ２１ are the same or different and each represents an alkyl group having 1 to 18 carbon atoms or Ar. １８ ~R ２１ Ar is an aryl group having 6 to 14 carbon atoms (excluding the number of carbon atoms of the substituent), and some of the hydrogen atoms in the aryl group are replaced by an alkyl group having 1 to 18 carbon atoms, an alkyl group having 1 to 8 carbon atoms substituted with a halogen atom, an alkenyl group having 2 to 18 carbon atoms, an alkynyl group having 2 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, a nitro group, a hydroxyl group, a cyano group, or -OR ２３ an alkoxy group or an aryloxy group represented by R ２４ an acyl group represented by CO—, R ２５ an acyloxy group represented by COO-; ２６ an alkylthio group or an arylthio group represented by the formula: ２７ R ２８ or a halogen atom, and R ２３ ~R ２６ is an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 14 carbon atoms. ２７ and R ２８ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms; E represents an element of Group 15 to 17 (IUPAC notation) with a valence of n, where n is an integer of 1 to 3; R ２２ is an organic group bonded to E. ２２ The number of R is n+1, and (n+1) R ２２ may be the same or different, and two or more R ２２ are directly connected to each other or are O-, -S-, -SO-, -SO ２ A ring structure containing the element E may be formed via -, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group.

[0081] The onium borate salt may contain an anion having a tetraphenylborate skeleton, and a hydrogen atom of a phenyl group of the tetraphenylborate skeleton may be substituted with at least one halogen atom selected from the group consisting of fluorine, chlorine, bromine, and iodine. The anion having a tetraphenylborate skeleton is preferably tetrakis(pentafluorophenyl)borate. The onium borate salt can be synthesized, for example, based on the method described in JP 2014-205624 A.

[0082] Examples of onium borate salts include 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, triarylsulfonium tetrakis(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)borate, and 4-isopropylphenyl(p-tolyl)iodonium tetrakis(pentafluorophenyl)borate.

[0083] The halogen-containing compound is not particularly limited, but examples thereof include compounds represented by the following formula (5).

[0084]

[0085] In the formula, E represents an element of group 15 to 17 (IUPAC notation) with a valence of n, and n is an integer of 1 to 3. ３０ is an organic group bonded to E. ３０ The number of R is n+1, and (n+1) R ３０ are the same or different, and two or more R ３０ are directly connected to each other or are O-, -S-, -SO-, -SO ２ A ring structure containing the element E may be formed via -, -NH-, -CO-, -COO-, -CONH-, an alkylene group, or a phenylene group. The organic group is not particularly limited, but may be, for example, an alkyl group having 1 to 18 carbon atoms, an aryl group, or a group having a heterocycle. The number of carbon atoms in the aryl group (excluding the number of carbon atoms in the substituent) is 6 to 14. The aryl group may have a substituent. X － is PF ６－ , SbF ６ － , AsF ６ － , SbCl ６ － , BiCl ５ － , SnCl ６ － , or ClO ４ － Shows.

[0086] The content of the polymerization initiator (B) relative to the optical component bonding composition (100% by mass) is not particularly limited, but is, for example, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and particularly preferably 0.4% by mass or more. Furthermore, for example, it is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less, and particularly preferably 2% by mass or less. The content of the polymerization initiator (B) relative to the optical component bonding composition (100% by mass) is, for example, preferably 0.01 to 5% by mass, more preferably 0.05 to 4% by mass, even more preferably 0.1 to 3% by mass, even more preferably 0.2 to 2% by mass, and particularly preferably 0.4 to 2% by mass.

[0087] The content of the polymerization initiator (B) relative to the siloxane compound (A) contained in the optical part bonding composition is not particularly limited, but is, for example, preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 1.0 mass% or more, and particularly preferably 1.5 mass% or more. Also, for example, it is preferably 20 mass% or less, more preferably 15 mass% or less, even more preferably 10 mass% or less, and particularly preferably 5 mass% or less. The content of the polymerization initiator (B) relative to the siloxane compound (A) contained in the optical part bonding composition is, for example, preferably 0.1 to 20 mass%, more preferably 0.5 to 15 mass%, even more preferably 1.0 to 10 mass%, and particularly preferably 1.5 to 5 mass%.

[0088] Filler (C) The filler (C) is not particularly limited, and examples thereof include inorganic fillers such as silica (silicon dioxide), talc, silicon carbide, silicon nitride, alumina (aluminum oxide), aluminum nitride, aluminum hydroxide, aluminum silicate, magnesium silicate, calcium silicate, calcium carbonate, barium sulfate, barium carbonate, titanium oxide, lime sulfate, potassium titanate, magnesium carbonate, zinc oxide, boron nitride, zirconia (zirconium oxide), and surface-treated inorganic fillers thereof; organic fillers such as silicone-based fillers containing a silicone-based elastomer such as polydimethylsiloxane as a rubber component; olefin-based fillers containing an olefin-based elastomer such as polybutadiene, polyisoprene, polychlorobutadiene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, or styrene-isoprene copolymer as a rubber component; and acrylic-based fillers containing an acrylic elastomer such as polypropyl(meth)acrylate, polybutyl(meth)acrylate, or polycyclohexyl(meth)acrylate as a rubber component. Among these, from the viewpoint of refractive index, surface-treated or untreated silica, silicone-based fillers, and acrylic-based fillers are preferred. In addition, in the above composition, one type of filler (C) may be used alone, or two or more types may be used in combination.

[0089] The filler (C) may be surface-treated with a surface treatment agent such as a silane coupling agent to prevent aggregation. The shape of the filler (C) is not particularly limited, and examples thereof include spherical (spherical, approximately spherical, etc.), polyhedral, rod-shaped (cylindrical, prismatic, etc.), plate-shaped, scaly, needle-shaped, and irregular shapes. Among these, when using a scaly or needle-shaped filler, if the orientation of the filler is disordered, light may be scattered, so from the viewpoint of refractive index and transmittance, the filler (C) is preferably spherical. When the filler (C) is spherical, its sphericity is preferably 0.8 or more, and more preferably 0.9 or more, approximately spherical.

[0090] The upper limit of the average particle size of the filler (C) is not particularly limited, but is preferably 5.0 μm or less, more preferably 3.0 μm or less, even more preferably 1.0 μm or less, and particularly preferably 0.5 μm or less. By setting the average particle size of the filler (C) to the above upper limit or less, high permeability tends to be exhibited. The lower limit of the average particle size of the filler (C) is not particularly limited, but from the viewpoint of the viscosity of the composition, it is preferably 0.01 μm or more, more preferably 0.03 μm or more, even more preferably 0.05 μm or more, and particularly preferably 0.08 μm or more. Fillers (C) with different average particle sizes may be used in combination; for example, a filler with an average particle size of 0.1 μm or more but less than 0.5 μm may be used in combination with a filler with an average particle size of 0.5 μm or more and 5.0 μm or less. In this specification, unless otherwise specified, the average particle size refers to the volume-based median diameter (D50) measured by a laser diffraction scattering method in accordance with ISO-13320 (2020).

[0091] In addition, when silica is used as a filler, its manufacturing method is not particularly limited. For example, spherical silica powder obtained by reacting metal silicon with oxygen, spherical silica powder obtained by melting pulverized silica, and silica fillers obtained by the sol-gel method, precipitation method, and aqueous solution wet method are exemplified. Among these, from the viewpoint of optical properties, silica particles obtained by the sol-gel method, i.e., sol-gel silica particles, which have high sphericity and a relatively sharp particle size distribution, are particularly preferred.

[0092] The content of the filler (C) relative to the optical component bonding composition (100% by mass) is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 30% by mass or more. Furthermore, it is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, and particularly preferably 70% by mass or less. The content of the filler (C) relative to the optical component bonding composition (100% by mass) is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, even more preferably 20 to 75% by mass, and particularly preferably 30 to 70% by mass. When the content of the filler (C) is within the above range, reflow resistance is improved and the refractive index of the cured product tends to decrease. Furthermore, yellowing resistance tends to be improved.

[0093] The content of the filler (C) relative to the siloxane compound (A) (100% by mass) contained in the optical component bonding composition is not particularly limited, but is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, and particularly preferably 80% by mass or more. Furthermore, it is preferably 400% by mass or less, more preferably 300% by mass or less, even more preferably 250% by mass or less, and particularly preferably 200% by mass or less. The content of the filler (C) relative to the siloxane compound (A) (100% by mass) contained in the optical component bonding composition is preferably 20 to 400% by mass, more preferably 40 to 300% by mass, even more preferably 60 to 250% by mass, and particularly preferably 80 to 200% by mass. When the content of the filler (C) is within the above range, reflow resistance is improved and the refractive index of the cured product tends to decrease. Furthermore, yellowing resistance tends to be improved.

[0094] Antioxidant (D) The antioxidant (D) is an agent used to prevent oxidation of the composition, the cured product, or the components contained therein. Examples include phenolic antioxidants, phosphite antioxidants, thioether antioxidants, amine antioxidants, and vinyl oxygen scavengers. From the viewpoint of yellowing resistance, the optical component adhesive composition preferably contains at least one antioxidant (D) selected from the group consisting of phenolic antioxidants and phosphite antioxidants, and more preferably contains a phenolic antioxidant and a phosphite antioxidant. In the composition, one type of antioxidant (D) may be used alone, or two or more types may be used in combination.

[0095] The phenolic antioxidant is not particularly limited as long as it has a phenol group in the molecule, and examples thereof include butylated hydroxyanisole, 2,6-di-t-butyl-p-cresol, 2,6-t-butyl-4-ethylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 4,4'-butylidene Bis(3-methyl-6-t-butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5.5]undecane, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5-di-t-butyl-4'-hydroxyphenyl)propionyloxy]ethyl] pionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-sec-triazine-2,4,6-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylin)methyl]-1,3,5-triazine diazine-2,4,6(1H,3H,5H)-trione, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylenebis[3-(3,N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, 2,6-di-tert-butyl-4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]phenol.

[0096] The phosphite antioxidants include organic phosphite esters (P(OR) ３ (R is an organic group)), and examples thereof include triphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, phenyl diisodecyl phosphite, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, diisodecyl pentaerythritol diphosphite, tris(nonylphenyl) phosphite, 2,2'-methylenebis(4, 6-di-t-butylphenyl)octyl phosphite, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, 4,4'-butylidene-bis(3-methyl-6-t-butylphenylditridecyl)phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, diphenyl isodecyl phosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol-diphosphite, and the like.

[0097] The thioether antioxidant is not particularly limited as long as it is a compound having a thioether bond in the molecule, and examples thereof include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3'-thiodipropionate.

[0098] The amine-based antioxidant is not particularly limited, and examples thereof include primary aliphatic amines such as ethylamine, propylamine, and butylamine; secondary aliphatic amines such as diethylamine, dipropylamine, and dibutylamine; primary aromatic amines such as aniline and its derivatives; and secondary aromatic amines such as phenothiazine.

[0099] The vinyl-based oxygen scavenger is a compound having a vinyl group in the molecule, and is not particularly limited as long as it is an agent that reduces curing inhibition due to oxygen and promotes curing, but examples include isoprenyl methacrylate, diprenyl glycerin ether, 1-(3-methyl-2-butenoxy)-2,3-hydroxypropane, 1,3-bis(3-methyl-2-butenoxy)-2-methacryloyloxypropane, α-(3-methyl-2-butenoxy)-ω-hydroxypoly[oxy(3-methyl-2-butenoxymethylethane-1,2-diyl)], α-methoxy-ω-hydroxypoly[oxy(3-methyl-2-butenoxymethylethane-1,2-diyl)], and the like.

[0100] The content of the antioxidant (D) relative to the optical component bonding composition (100% by mass) is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and particularly preferably 0.3% by mass or more. Furthermore, the content is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less, even more preferably 4% by mass or less, even more preferably 3% by mass or less, and particularly preferably 2% by mass or less. The content of the antioxidant (D) relative to the optical component bonding composition (100% by mass) is preferably 0.01 to 10% by mass, more preferably 0.05 to 8% by mass, more preferably 0.1 to 6% by mass, more preferably 0.3 to 4% by mass, even more preferably 0.3 to 3% by mass, and particularly preferably 0.3 to 2% by mass. Having the antioxidant (D) content within the above range tends to further improve yellowing resistance.

[0101] The content (total amount) of the phenolic antioxidant and the phosphite antioxidant relative to the optical component bonding composition (100% by mass) is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and particularly preferably 0.3% by mass or more. Also, for example, it is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less, even more preferably 4% by mass or less, even more preferably 3% by mass or less, and particularly preferably 2% by mass or less. The content (total amount) of the phenolic antioxidant and the phosphite antioxidant relative to the optical component bonding composition (100% by mass) is, for example, preferably 0.01 to 10% by mass, more preferably 0.05 to 8% by mass, more preferably 0.1 to 6% by mass, more preferably 0.3 to 4% by mass, even more preferably 0.3 to 3% by mass, and particularly preferably 0.3 to 2% by mass. When the content (total amount) of the phenolic antioxidant and the phosphite antioxidant is within the above range, yellowing resistance tends to be further improved.

[0102] The content (total amount) of the phenolic antioxidant and the phosphite antioxidant relative to the siloxane compound (A) contained in the optical component bonding composition is not particularly limited, but is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, even more preferably 0.6 mass% or more, and particularly preferably 1.0 mass% or more. Furthermore, it is preferably 20 mass% or less, more preferably 15 mass% or less, even more preferably 10 mass% or less, and particularly preferably 5 mass% or less. The content (total amount) of the phenolic antioxidant and the phosphite antioxidant relative to the siloxane compound (A) contained in the optical component bonding composition is preferably 0.1 to 20 mass%, more preferably 0.3 to 15 mass%, even more preferably 0.6 to 10 mass%, and particularly preferably 1.0 to 5 mass%. Having the content (total amount) of the phenolic antioxidant and the phosphite antioxidant within the above range tends to further improve yellowing resistance.

[0103] Other Additives (E) The composition for bonding optical components may contain additives such as epoxy resins (e.g., alicyclic epoxy resins), core-shell rubber particles (e.g., acrylonitrile rubber particles), photosensitizers, coupling agents, stabilizers, ion trapping agents, leveling agents, antifoaming agents, viscosity modifiers, and solvents (hereinafter referred to as "other additives (E)") within a range that does not impair the effects of the present invention. The content of each additive can be appropriately selected.

[0104] The method for producing the optical component adhesive composition is not particularly limited. For example, the siloxane compound (A), polymerization initiator (B), filler (C), antioxidant (D), and optionally other additives (E) can be simultaneously or separately introduced into an appropriate mixer, and the mixture is stirred and mixed homogeneously while melting by heating if necessary to obtain the composition. Examples of the mixer that can be used include a Raikai mixer, Henschel mixer, three-roll mill, ball mill, planetary mixer, and bead mill, all equipped with a stirrer and a heater. These devices may also be used in combination as appropriate.

[0105] The viscosity of the composition at 25°C is not particularly limited, but is preferably 0.01 to 10,000 mPa·s, more preferably 0.1 to 5,000 mPa·s, even more preferably 1 to 3,000 mPa·s, and particularly preferably 10 to 1,000 mPa·s. In this specification, unless otherwise specified, viscosity is expressed as a value measured in accordance with Japanese Industrial Standard JIS K6833. Specifically, it can be determined by measuring using an E-type viscometer at a rotation speed of 10 rpm. There are no particular limitations on the equipment, rotor, or measurement range used.

[0106] The composition preferably has a retention rate (%) of 72.0% or more, as calculated by the following formula. The following transmittances are values ​​measured at 25°C. Retention rate (%) = Transmittance (%) of cured product (after heat treatment) at a wavelength of 425 nm / Transmittance (%) of cured product (initial) at a wavelength of 425 nm × 100 Cured product (initial): Cured product 1 hour after completion of curing of the composition Cured product (after heat treatment): Cured product after the cured product (initial) was reflowed five times at 260°C in a nitrogen atmosphere, and then exposed to and heat-treated at 200°C in an air atmosphere for 4 hours. The method for measuring the retention rate will be described in detail in the examples below.

[0107] The higher the retention rate (%), the higher the yellowing resistance of the cured product. This is because the transmittance of the cured product at a wavelength of 425 nm is an indicator of the yellowing of the cured product. In other words, the lower the transmittance, the more yellow the cured product turns. The retention rate is an indicator of the degree to which the cured product turns yellow upon heat treatment; a high value indicates a slow rate of yellowing of the cured product, while a low value indicates a fast rate of yellowing of the cured product.

[0108] The optical component bonding composition of the present invention has excellent optical properties and heat resistance, and therefore can be used to bond various optical components, and is particularly suitable for use as an optical adhesive for silicon photonics. Examples of optical components that can be bonded with the composition include optical fibers, optical fiber arrays, and optical waveguide elements. Furthermore, the composition is preferably used for bonding optical fibers and optical waveguide elements.

[0109] The applications of the adhesive composition for optical components of the present invention will be described with reference to Fig. 1. The composition has applications for fixing an optical fiber 10 to a V-shaped groove (referred to as a "V groove") 33 formed in an optical waveguide element 30, and for optically coupling the optical fiber 10 to an optical waveguide 32 of the optical waveguide element 30. The composition may also be used to fulfill these applications simultaneously.

[0110] [Cured Product] The optical part bonding composition of the present invention can be cured to form a cured product by irradiating it with the above-mentioned active energy rays, preferably light with a wavelength of 10 to 600 nm, more preferably ultraviolet light with a wavelength of 100 to 500 nm, even more preferably ultraviolet light with a wavelength of 250 to 450 nm, and particularly preferably ultraviolet light with a wavelength of 300 to 400 nm. When the composition is cured by ultraviolet irradiation, the irradiation amount (cumulative light amount) of the ultraviolet light used is, for example, 500 to 30,000 mJ / cm. ２ The device used for irradiating ultraviolet light is not particularly limited, and any known and commonly used device can be used.

[0111] The refractive index of the cured product at a wavelength of 1310 nm at 25°C is not particularly limited, but is preferably 1.47 or less, more preferably 1.46 or less, even more preferably 1.45 or less, and particularly preferably 1.44 or less. In this specification, unless otherwise specified, the refractive index is expressed as a value measured in accordance with JIS K7142:2014A method.

[0112] When the thickness of the cured product is 0.3 μm, the transmittance at a wavelength of 1,310 nm at 25° C. is not particularly limited, but from the viewpoint of optical properties, it is preferably 80% or more, more preferably 85% or more, even more preferably 90% or more, and particularly preferably 92% or more. In this specification, transmittance is expressed as a value measured in accordance with JIS K7105, unless otherwise specified.

[0113] When the thickness of the cured product is 0.3 μm, the transmittance at 25° C. at a wavelength of 425 nm is not particularly limited, but from the viewpoint of optical properties, it is preferably 80% or more, more preferably 85% or more, even more preferably 90% or more, and particularly preferably 92% or more.

[0114] The cured product has particularly excellent reflow resistance. The reflow resistance refers to the ability to withstand thermal shock at a maximum temperature of 260°C for 1 minute. In other words, the cured product has the property of showing little change in physical properties before and after the reflow process (maximum temperature of about 260°C) used for soldering when mounting electronic components. For example, the composition has the property of showing little change in adhesive strength before and after the reflow process when cured.

[0115] [Optical fiber array] The adhesive composition for optical components of the present invention is preferably used for bonding optical fibers and optical waveguide elements. Specifically, the composition is preferably used for constructing an optical fiber array 1. The optical fiber array 1 includes optical fibers 10 and an adhesive layer 20. The optical fibers 10 are covered with a coating 11 and are shown in the form of ribbon fibers 12. In the optical fiber array 1, the optical fibers 10 are optically coupled to the optical waveguides 32 of the optical waveguide element 30 by the adhesive layer 20.

[0116] 1 to 4, the optical fiber array 1 has a substrate 31 in which V-grooves 33, which are grooves for accommodating optical fibers 10, are formed, and a presser plate 40 adhesively fixed to the surface of the optical fibers 10, and the optical fibers 10 are adhesively fixed to the V-grooves 33 by an adhesive layer 20 (FIGS. 3 and 4). The adhesive layer 20 bonds the optical fibers 10 to the optical waveguide elements 30 (FIG. 3), and also bonds the substrate 31 with the optical fibers 10 accommodated in the V-grooves 33 to the presser plate 40 (FIG. 4).

[0117] The substrate 31 may be made of glass, a semiconductor, an organic resin, or the like, with a semiconductor substrate being preferable. The substrate may also have a ball grid array electrode (not shown) on one surface. Providing a ball grid array electrode on one surface of the substrate allows for a high density of multiple electrical interfaces, thereby enabling the miniaturization of silicon photonics devices. The ball grid array electrode is positioned with the expectation that it will be mounted and fixed to another substrate or the like by a reflow process. Therefore, the adhesive layer in the optical fiber array must be heat-resistant so that it can withstand the temperature and time required during reflow heating.

[0118] The adhesive layer 20 is a cured product of the optical component bonding composition of the present invention. That is, the optical fiber array 1 includes optical fibers 10 and the adhesive layer 20, the optical fibers 10 are optically bonded to the optical waveguide element 30 by the adhesive layer 20, and the adhesive layer 20 is made of the above-mentioned cured product. In other words, the optical fiber array 1 includes a cured product of the optical component bonding composition, the optical fibers 10, and the optical waveguide element 30, and the optical fibers 10 are optically bonded to the optical waveguide element 30 by the optical component bonding composition or a cured product thereof.

[0119] The optical fiber array 1 has a substrate 31 in which a V-groove 33 for arranging the optical fiber 10 is formed, and a pressure plate 40 adhesively fixed to the surface of the optical fiber 10, and the optical fiber 10 is adhesively fixed to the V-groove 33 by an adhesive layer 20, which bonds the optical fiber 10 to the optical waveguide element 30 and also bonds the substrate 31 with the optical fiber 10 arranged in the V-groove 33 to the pressure plate 40.

[0120] As shown in FIG. 1 , an optical waveguide module 50 (optical waveguide device) can be constructed using an optical fiber array 1. The optical waveguide module 50 includes the optical fiber array 1. Specifically, the optical waveguide module 50 includes the optical fiber array 1, an adhesive layer 20, and an optical waveguide element 30, and the optical fiber array 1 is optically coupled to the optical waveguide 32 of the optical waveguide element 30 via the adhesive layer 20. The adhesive layer 20 is formed using the optical component adhesive composition of the present invention. Note that the optical fiber array 1 and the optical waveguide element 30 in the optical waveguide module 50 are not particularly limited as long as they are used in optical integrated circuits. It is preferable that the optical waveguide module 50 be incorporated as a silicon photonics device.

[0121] [Method for manufacturing an optical fiber array] The method for manufacturing an optical fiber array 1 is a method for manufacturing an optical fiber array 1 in which optical fibers 10 are optically coupled to an optical waveguide element 30 by an adhesive layer 20, and the adhesive layer 20 is formed from a cured product of the optical component bonding composition of the present invention. In this case, the step of fixing the optical fibers 10 in the V-grooves 33, which are grooves formed in the optical waveguide element 30, and the step of optically coupling the optical fibers 10 to the optical waveguides 32 of the optical waveguide element 30 may be performed separately, but are preferably performed simultaneously.

[0122] An example of a method for fixing the optical fiber 10 to the optical waveguide element 30 will be described below. First, the optical fiber 10 is placed along the V-groove 33, and the end of the optical fiber 10 is brought into contact with the side surface on the optical waveguide 32 side. Here, accurate alignment is performed to reduce loss at the connection point between the optical fiber 10 and the optical waveguide 32. Next, a presser plate 40 is placed on the optical fiber 10. Thereafter, an optical component adhesive composition is dropped into the V-groove 33. The presser plate 40 may be formed integrally with the substrate 31.

[0123] The optical component adhesive composition supplied to the V-groove 33 permeates into the gap between the optical fiber 10 and the V-groove 33 by capillary action, permeates along the contact portion between the optical fiber 10 and the presser plate 40, and also permeates into the gap between the optical fiber 10 and the optical waveguide 32. Therefore, the optical component adhesive composition is required to have an appropriate injectability so that it can permeate into both the gap between the optical fiber 10 and the V-groove 33 and the gap between the optical fiber 10 and the optical waveguide 32.

[0124] Next, the optical component bonding composition is cured by irradiation with active energy rays (e.g., ultraviolet rays), thereby bonding the optical fiber 10 to the optical waveguide 32, the optical fiber 10 to the V-groove 33, and the optical fiber 10 to the presser plate 40. Note that a thermal curing step may be added after the step of curing the optical component bonding composition with active energy rays or during the irradiation of active energy rays. In other words, the adhesive layer 20 can also serve to optically couple the optical fiber 10 to the optical waveguide 32 of the optical waveguide element 30, fix the optical fiber 10 in the V-groove 33, which is a groove portion formed in the optical waveguide element 30, and fix the optical fiber 10 to the presser plate 40. In other words, the adhesive layer 20 can perform bonding for optical path coupling and bonding for V-groove fixation at the same time with a single adhesive layer. The adhesive layer 20 does not necessarily have to perform these bonding operations simultaneously, and may be used as an adhesive layer for optically coupling the optical fiber 10 to the optical waveguide 32 of the optical waveguide element 30, or as an adhesive layer for V-groove fixation for fixing the optical fiber 10 to the V-groove 33, which is a groove portion formed in the optical waveguide element 30.

[0125] As will be shown in the examples described later, the optical part bonding composition of the present invention can suppress a decrease in transmittance when it is cured. Therefore, the present invention provides a method for suppressing a decrease in transmittance when it is cured from the optical part bonding composition.

[0126] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0127] The compositions of Examples 1 to 5 and Comparative Example 1 were prepared by mixing the components using a three-roll mill according to the formulations shown in Table 1. The numerical values ​​for each component in Table 1 indicate parts by mass (unit: g).

[0128] Each component in Table 1 will be explained below. Siloxane compound (A1) X-40-2728 (product name): a cyclic siloxane compound represented by the following formula (R is an alkyl group), manufactured by Shin-Etsu Chemical Co., Ltd., containing a non-alicyclic epoxy group, having two epoxy functional groups, a viscosity of 26 mPa·s at 25°C, and an epoxy equivalent of 280 g / mol. KR-470 (product name): Cyclic siloxane compound represented by the following formula, manufactured by Shin-Etsu Chemical Co., Ltd., containing alicyclic epoxy groups, epoxy functional group number 4, viscosity at 25°C 3000 mPa s, epoxy equivalent 200 g / mol Siloxane compound (A2) X-22-169AS (product name): a chain siloxane compound represented by the following formula, manufactured by Shin-Etsu Chemical Co., Ltd., containing alicyclic epoxy groups at both ends of the molecule, with a viscosity of 25 mPa·s at 25°C and an epoxy equivalent of 500 g / mol X-40-2669 (product name): A chain siloxane compound represented by the following formula, manufactured by Shin-Etsu Chemical Co., Ltd., containing an alicyclic epoxy group, with a viscosity of 35 mPa·s at 25°C and an epoxy equivalent of 200 g / mol.

[0129] Polymerization initiator (B) IK-1FG (product name): gallate-based photoacid generator (iodonium salt-type photoacid generator), manufactured by San-Apro Co., Ltd.

[0130] Filler (C) KE-S30HG (product name): spherical sol-gel silica particles with an average particle size of 0.3 μm, manufactured by Nippon Shokubai Co., Ltd. GM-0205S: product name "Ganz Pearl GM-0205S", polyacrylate filler with an average particle size of 0.1 μm, manufactured by Aica Kogyo Co., Ltd. SI-020: product name "Ganz Pearl SI-020", silicone filler with an average particle size of 0.1 μm, manufactured by Aica Kogyo Co., Ltd.

[0131] Antioxidants (D) PEP-8: product name "ADK STAB PEP-8", phosphite antioxidant, 3,9-bis(octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, manufactured by ADEKA Corporation PEP-36: product name "ADK STAB PEP-36", phosphite antioxidant, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, manufactured by ADEKA Corporation AO-20: product name "ADK STAB AO-20, a phenolic antioxidant, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, manufactured by ADEKA Corporation

[0132] Additive (E) KBM-103 (product name): phenyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. UVS-1331: product name "Anthracure UVS-1331", anthracene type photosensitizer, 9,10-dibutoxyanthracene, manufactured by Air Water Inc. UVS-2171: product name "Anthracure UVS-2171", naphthalene type photosensitizer, 1,4-diethoxynaphthalene, manufactured by Air Water Inc. RKB-5810 (product name): nano rubber filler-containing alicyclic epoxy resin, manufactured by Resinous Kasei Co., Ltd.

[0133] [Evaluation] The compositions of Examples 1 to 5 and Comparative Example 1 were cured, and the transmittance of the cured products was measured as follows.

[0134] (Measurement and Calculation of Transmittance and Retention Rate of Cured Products) The compositions of Examples 1 to 5 and Comparative Example 1 were cured under the following conditions to produce cured products with a thickness of 0.3 mm. Curing conditions: The composition was applied to a PET film on a glass slide to a thickness of 0.3 mm, and then irradiated with a UV irradiator with a metal halide lamp light source at a peak wavelength of 365 nm and a radiation intensity of 30,000 mJ / cm. ２The composition was cured by UV irradiation with an integrated light dose of 1000 kJ / min, then dried in a dryer at 120°C for 60 minutes, and then peeled off from the PET film. The resulting cured product was left to stand at 25°C for 1 hour, and this is referred to as the "cured product (initial)." The resulting cured product was then reflowed by passing it through a reflow oven (MK1809, manufactured by HELLER, conveyor speed: 32.05 cm / min) five times under a nitrogen atmosphere, with a peak temperature of 260°C maintained for 60 seconds, and then heat-treated by exposure to 200°C for 4 hours in an air atmosphere. This product is referred to as the "cured product (after heat treatment)."

[0135] The transmittance (25°C) of the cured product (initial) and the cured product (after heat treatment) at a wavelength of 425 nm was measured using an ultraviolet-visible spectrophotometer (product name "V-670", manufactured by JASCO Corporation). The results are shown in Table 1 under "Initial" and "After heat treatment" under "Transmittance (%) at a wavelength of 425 nm." The retention rate (%) calculated using the following formula is also shown in the "Retention rate (%)" section of the same table. Retention rate (%) = Transmittance (%) at a wavelength of 425 nm of the cured product (after heat treatment) / Transmittance (%) at a wavelength of 425 nm of the cured product (initial) × 100

[0136]

[0137] Variations of the invention according to the present disclosure are described below. [Appendix 1] An optical component bonding composition comprising a siloxane compound (A) having a reactive functional group, a polymerization initiator (B), a filler (C), and an antioxidant (D). [Appendix 2] The optical component bonding composition according to Appendix 1, in which the siloxane compound (A) contains, as a reactive functional group, a group containing a cationically polymerizable group (e.g., a group containing at least one cationically polymerizable group selected from the group consisting of a group containing an epoxy group, a group containing an oxetanyl group, and a group containing a vinyl ether group) and / or a group containing a radically polymerizable group (e.g., a group containing at least one radically polymerizable group selected from the group consisting of a group containing a vinyl group and a group containing a (meth)acryloyl group). [Appendix 3] The optical component bonding composition according to Appendix 1 or Appendix 2, in which the siloxane compound (A) has 2 or more, 2 to 30, or 3 to 20 reactive functional groups. [Appendix 4] The optical part bonding composition according to any one of Appendices 1 to 3, comprising, as the siloxane compound (A), a cyclic siloxane compound (A1) having a reactive functional group and / or a chain siloxane compound (A2) having a reactive functional group. [Appendix 5] The optical part bonding composition according to Appendices 4, wherein the number of Si—O units in the siloxane ring in the siloxane compound (A1) is 2 to 15, 3 to 10, 3 to 8, or 3 to 6. [Appendix 6] The optical part bonding composition according to Appendices 4 or 5, wherein the siloxane compound (A1) comprises, as the reactive functional group, a group containing a cationically polymerizable group (e.g., a group containing at least one cationically polymerizable group selected from the group consisting of a group containing an epoxy group, a group containing an oxetanyl group, and a group containing a vinyl ether group), and / or a group containing a radically polymerizable group (e.g., a group containing at least one radically polymerizable group selected from the group consisting of a group containing a vinyl group and a group containing a (meth)acryloyl group). [Appendix 7] The optical part bonding composition according to any one of Appendices 4 to 6, wherein the siloxane compound (A1) has a group containing an epoxy group as a reactive functional group.[Appendix 8] The optical part bonding composition according to Appendix 7, wherein the group containing an epoxy group is a group containing an alicyclic epoxy group and / or a group containing a non-alicyclic epoxy group. [Appendix 9] The optical part bonding composition according to any one of Appendix 6 to Appendix 8, wherein the siloxane compound (A1) has 2 or more, 2 to 10, 2 to 6, 2 to 4, or 2 or 4 groups containing a cationically polymerizable group as reactive functional groups. [Appendix 10] The siloxane compound (A1) is a siloxane compound represented by the above formula (1) (wherein n represents an integer of 3 to 10, or 4 to 6. R １ and R ２ are the same or different and represent a group containing an epoxy group or a hydrocarbon group, provided that n R １ and R ２ At least one of R is a group containing an epoxy group. １ and R ２wherein the hydrocarbon group may be an alkyl group, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. [Appendix 11] The optical part bonding composition according to any one of Appendices 4 to 10, wherein the siloxane compound (A1) has an epoxy equivalent (g / mol) of 50 to 1000, 100 to 500, or 150 to 400. [Appendix 12] The optical part bonding composition according to any one of Appendices 4 to 11, wherein the siloxane compound (A1) has a weight average molecular weight of 200 to 3000, 300 to 2000, or 400 to 1000. [Appendix 13] The optical part bonding composition according to any one of Appendices 4 to 12, wherein the number of Si—O units in the siloxane chain in the siloxane compound (A2) is 2 to 50, 3 to 40, 5 to 30, or 10 to 20. [Appendix 14] The optical part bonding composition according to any one of Appendices 4 to 13, wherein the siloxane compound (A2) contains, as a reactive functional group, a group containing a cationically polymerizable group (for example, a group containing at least one cationically polymerizable group selected from the group consisting of a group containing an epoxy group, a group containing an oxetanyl group, and a group containing a vinyl ether group), and / or a group containing a radically polymerizable group (for example, a group containing at least one radically polymerizable group selected from the group consisting of a group containing a vinyl group and a group containing a (meth)acryloyl group). [Appendix 15] The optical part bonding composition according to any one of Appendices 4 to 14, wherein the siloxane compound (A2) has, as a reactive functional group, a group containing an epoxy group. [Appendix 16] The optical part bonding composition according to Appendices 15, wherein the group containing an epoxy group is a group containing an alicyclic epoxy group and / or a group containing a non-alicyclic epoxy group. [Appendix 17] The optical part bonding composition according to any one of Appendices 14 to 16, wherein the siloxane compound (A2) has 2 or more, 2 to 10, 2 to 6, 2 to 4, or 2 groups containing a cationically polymerizable group as a reactive functional group. [Appendix 18] The optical part bonding composition according to any one of Appendices 14 to 16, wherein the siloxane compound (A2) is a compound represented by the above formula (2) (wherein, R ３ and R ８ are the same or different and represent a group containing an epoxy group.４ , R ５ , R ６ , R ７ , R ９ , R １１ , and R １２ are the same or different and represent a hydrocarbon group. １０ are the same or different and represent a group containing a hydrocarbon group or an epoxy group. m is an integer of 0 to 3000. n is an integer of 0 to 3000. R ３ , R ８ , and R １０ The group containing an epoxy group in R may be a group containing an alicyclic epoxy group or a group containing a non-alicyclic epoxy group. ４ ~R ７ and R ９ ~R １２wherein the hydrocarbon group may be an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. [Appendix 19] The optical part bonding composition according to any one of Appendices 4 to 18, wherein the siloxane compound (A2) has an epoxy equivalent (g / mol) of 100 to 4,000, 120 to 2,000, or 150 to 1,000. [Appendix 20] The optical part bonding composition according to any one of Appendices 4 to 19, wherein the siloxane compound (A2) has a weight average molecular weight of 200 to 10,000, 200 to 8,000, or 400 to 6,000. [Appendix 21] The optical part bonding composition according to any one of Appendices 1 to 20, wherein the content of the siloxane compound (A) relative to the optical part bonding composition (100 mass%) is 5 mass% or more, 10 mass% or more, 20 mass% or more, or 30 mass% or more; 90 mass% or less, 75 mass% or less, 60 mass% or less, 50 mass% or less, or 45 mass% or less; and / or 5 to 90 mass%, 10 to 75 mass%, 20 to 60 mass%, 30 to 50 mass%, or 30 to 45 mass%. [Appendix 22] The optical part bonding composition according to any one of Appendices 4 to 21, wherein the content (total amount) of the siloxane compound (A1) and the siloxane compound (A2) relative to the optical part bonding composition (100 mass%) is 5 mass% or more, 10 mass% or more, 20 mass% or more, or 30 mass% or more; 90 mass% or less, 75 mass% or less, 60 mass% or less, 50 mass% or less, or 45 mass% or less; and / or 5 to 90 mass%, 10 to 75 mass%, 20 to 60 mass%, 30 to 50 mass%, or 30 to 45 mass%. [Appendix 23] The optical part bonding composition according to any one of Appendices 4 to 22, wherein the content of the siloxane compound (A1) relative to the optical part bonding composition (100 mass%) is 2 mass% or more, 4 mass% or more, 6 mass% or more, 8 mass% or more, or 10 mass% or more; 30 mass% or less, 25 mass% or less, 20 mass% or less, or 15 mass% or less; and / or 2 to 30 mass%, 4 to 25 mass%, 6 to 20 mass%, 8 to 15 mass%, or 10 to 15 mass%.[Appendix 24] The optical part bonding composition according to any one of Appendices 4 to 23, wherein the content of the siloxane compound (A2) relative to the optical part bonding composition (100 mass%) is 4 mass% or more, 8 mass% or more, 12 mass% or more, 16 mass% or more, or 20 mass% or more; 60 mass% or less, 50 mass% or less, 40 mass% or less, or 30 mass% or less; and / or 4 to 60 mass%, 8 to 50 mass%, 12 to 40 mass%, 16 to 30 mass%, or 20 to 30 mass%. [Appendix 25] The optical part bonding composition according to any one of Appendices 4 to 24, wherein a mass ratio of the siloxane compound (A1) to the siloxane compound (A2) (siloxane compound (A1):siloxane compound (A2)) is 90:10 to 5:95, 70:30 to 15:85, 60:40 to 20:80, 50:50 to 25:75, 45:55 to 30:70, or 40:60 to 30:70. [Appendix 26] The optical part bonding composition according to any one of Appendices 1 to 25, wherein the polymerization initiator (B) is at least one selected from a photopolymerization initiator and a thermal polymerization initiator. [Appendix 27] The optical part bonding composition according to Appendices 26, wherein the photopolymerization initiator comprises at least one photoacid generator selected from an onium salt, a halogen-containing compound, a diazomethane compound, a sulfone compound, and a sulfonic acid compound. [Appendix 28] The optical part bonding composition according to Appendix 27, wherein the onium salt is at least one onium salt selected from the group consisting of onium gallate salts and onium borate salts. [Appendix 29] The optical part bonding composition according to any one of Appendices 1 to 28, wherein a content of the polymerization initiator (B) relative to the optical part bonding composition (100 mass%) is 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.2 mass% or more, or 0.4 mass% or more; 5 mass% or less, 4 mass% or less, 3 mass% or less, or 2 mass% or less; and / or 0.01 to 5 mass%, 0.05 to 4 mass%, 0.1 to 3 mass%, 0.2 to 2 mass%, or 0.4 to 2 mass%.[Appendix 30] The optical part bonding composition according to any one of Appendices 1 to 29, wherein the content of the polymerization initiator (B) relative to the siloxane compound (A) is 0.1 mass% or more, 0.5 mass% or more, 1.0 mass% or more, or 1.5 mass% or more; 20 mass% or less, 15 mass% or less, 10 mass% or less, or 5 mass% or less; and / or 0.1 to 20 mass%, 0.5 to 15 mass%, 1.0 to 10 mass%, or 1.5 to 5 mass%. [Appendix 31] The optical component bonding composition according to any one of Appendix 1 to Appendix 30, wherein the filler (C) is an inorganic filler selected from the group consisting of silica (silicon dioxide), talc, silicon carbide, silicon nitride, alumina (aluminum oxide), aluminum nitride, aluminum hydroxide, aluminum silicate, magnesium silicate, calcium silicate, calcium carbonate, barium sulfate, barium carbonate, titanium oxide, lime sulfate, potassium titanate, magnesium carbonate, zinc oxide, boron nitride, zirconia (zirconium oxide), and surface-treated inorganic fillers thereof; or an organic filler such as a silicone filler containing a silicone elastomer such as polydimethylsiloxane as a rubber component, an olefin filler containing an olefin elastomer such as polybutadiene, polyisoprene, polychlorobutadiene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, or styrene-isoprene copolymer as a rubber component, or an acrylic filler containing an acrylic elastomer such as polypropyl(meth)acrylate, polybutyl(meth)acrylate, or polycyclohexyl(meth)acrylate as a rubber component. [Appendix 32] The optical part bonding composition according to Appendix 31, wherein the filler (C) is surface-treated with a silane coupling agent. [Appendix 33] The optical part bonding composition according to any one of Appendices 1 to 32, wherein the filler (C) has an average particle size of 5.0 μm or less, 3.0 μm or less, 1.0 μm or less, or 0.5 μm or less; 0.01 μm or more, 0.03 μm or more, 0.05 μm or more, or 0.08 μm or more; and / or 5.0 to 0.01 μm, 3.0 to 0.03 μm, 1.0 to 0.05 μm, or 0.5 to 0.08 μm.[Appendix 34] The optical part bonding composition according to any one of Appendices 1 to 33, wherein the content of the filler (C) relative to the optical part bonding composition (100 mass%) is 5 mass% or more, 10 mass% or more, 20 mass% or more, or 30 mass% or more; 90 mass% or less, 80 mass% or less, 75 mass% or less, or 70 mass% or less; and / or 5 to 90 mass%, 10 to 80 mass%, 20 to 75 mass%, or 30 to 70 mass%. [Appendix 35] The optical part bonding composition according to any one of Appendices 1 to 34, wherein the content of the filler (C) relative to the siloxane compound (A) (100 mass%) is 20 mass% or more, 40 mass% or more, 60 mass% or more, or 80 mass% or more; 400 mass% or less, 300 mass% or less, 250 mass% or less, or 200 mass% or less; and / or 20 to 400 mass%, 40 to 300 mass%, 60 to 250 mass%, or 80 to 200 mass%. [Appendix 36] The optical part bonding composition according to any one of Appendices 1 to 35, wherein the antioxidant (D) includes at least one selected from the group consisting of a phenolic antioxidant, a phosphite-based antioxidant, a thioether-based antioxidant, an amine-based antioxidant, and a vinyl-based oxygen scavenger, or includes at least one selected from the group consisting of a phenolic antioxidant and a phosphite-based antioxidant. [Appendix 37] The optical part bonding composition according to any one of Appendices 1 to 36, wherein the content of the antioxidant (D) relative to the optical part bonding composition (100 mass%) is 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, or 0.3 mass% or more; 10 mass% or less, 8 mass% or less, 6 mass% or less, 4 mass% or less, 3 mass% or less, or 2 mass% or less; and / or 0.01 to 10 mass%, 0.05 to 8 mass%, 0.1 to 6 mass%, 0.3 to 4 mass%, 0.3 to 3 mass%, or 0.3 to 2 mass%.[Appendix 38] The optical part bonding composition according to any one of Appendix 36 or Appendix 37, wherein the content (total amount) of the phenolic antioxidant and the phosphite-based antioxidant relative to the optical part bonding composition (100 mass%) is 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, or 0.3 mass% or more; 10 mass% or less, 8 mass% or less, 6 mass% or less, 4 mass% or less, 3 mass% or less, or 2 mass% or less; and / or 0.01 to 10 mass%, 0.05 to 8 mass%, 0.1 to 6 mass%, 0.3 to 4 mass%, 0.3 to 3 mass%, or 0.3 to 2 mass%. [Appendix 39] The optical part bonding composition according to any one of Appendices 36 to 38, wherein the content (total amount) of the phenolic antioxidant and the phosphite antioxidant relative to the siloxane compound (A) is 0.1% by mass or more, 0.3% by mass or more, or 0.6% by mass or more, 1.0% by mass or more, 20% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less; and / or 0.1 to 20% by mass, 0.3 to 15% by mass, 0.6 to 10% by mass, or 1.0 to 5% by mass. [Appendix 40] The optical part bonding composition according to any one of Appendices 1 to 39, wherein the viscosity at 25°C is 0.01 to 10,000 mPa s, 0.1 to 5,000 mPa s, 1 to 3,000 mPa s, or 10 to 1,000 mPa s. [Appendix 41] The optical part bonding composition according to any one of Appendices 1 to 40, having a retention rate (%) calculated by the following formula of 72.0% or more: Retention rate (%) = Transmittance (%) of cured product (after heat treatment) at a wavelength of 425 nm / Transmittance (%) of cured product (initial) at a wavelength of 425 nm × 100 Cured product (initial): The cured product one hour after completion of curing of the composition Cured product (after heat treatment): The cured product (initial) is reflowed five times at 260°C in a nitrogen atmosphere, and then exposed to and heat-treated at 200°C in an air atmosphere for four hours. The transmittance of the cured product is the value measured at 25°C. [Appendix 42] The optical part bonding composition according to any one of Appendices 1 to 41, having a refractive index at a wavelength of 1310 nm at 25°C of 1.47 or less, 1.46 or less, 1.45 or less, or 1.44 or less.[Appendix 43] The optical component bonding composition according to any one of Appendices 1 to 42, wherein, when the thickness of the cured product is 0.3 μm, the transmittance at 25°C at a wavelength of 1310 nm is 80% or more, 85% or more, 90% or more, or 92% or more. [Appendix 44] The optical component bonding composition according to any one of Appendices 1 to 43, wherein, when the thickness of the cured product is 0.3 μm, the transmittance at 25°C at a wavelength of 425 nm is 80% or more, 85% or more, 90% or more, or 92% or more. [Appendix 45] The optical component bonding composition according to any one of Appendices 1 to 44, which is used for fixing an optical fiber to a groove formed in an optical waveguide element. [Appendix 46] The optical component bonding composition according to any one of Appendices 1 to 45, which is used for optically coupling an optical fiber to an optical waveguide element. [Appendix 47] The optical component bonding composition according to any one of Appendices 1 to 46, which is used for simultaneously fixing an optical fiber to a groove formed in an optical waveguide element and optically coupling the optical fiber to the optical waveguide element. [Appendix 48] A cured product of the optical component bonding composition according to any one of Appendices 1 to 47. [Appendix 49] An optical fiber array comprising: the optical component bonding composition according to any one of Appendices 1 to 47; an optical fiber; and an optical waveguide element, wherein the optical fiber is optically coupled to the optical waveguide element by the optical component bonding composition.

[0138] The optical component bonding composition of the present invention has excellent yellowing resistance when cured, and an optical fiber array including the cured composition has a good appearance due to the excellent yellowing resistance of the cured product.

[0139] REFERENCE SIGNS LIST 1 Optical fiber array 10 Optical fiber 11 Coating 12 Ribbon fiber 20 Adhesive layer 30 Optical waveguide element 31 Substrate 32 Optical waveguide 33 V-groove (groove portion) 40 Pressing plate 50 Optical waveguide module (optical waveguide device)

Claims

1. A composition for bonding optical components, comprising a siloxane compound (A) having a reactive functional group, a polymerization initiator (B), a filler (C), and an antioxidant (D).

2. The optical component bonding composition according to claim 1, wherein the antioxidant (D) is at least one selected from the group consisting of phenol-based antioxidants and phosphite-based antioxidants.

3. The optical component bonding composition according to claim 1 or 2, wherein the siloxane compound (A) having a reactive functional group comprises a cyclic siloxane compound (A1) having a reactive functional group and a chain siloxane compound (A2) having a reactive functional group.

4. The optical component bonding composition according to claim 3, wherein the cyclic siloxane compound (A1) having a reactive functional group has two or more groups containing a cationically polymerizable group as the reactive functional group.

5. The optical component bonding composition according to claim 3, wherein the cyclic siloxane compound (A1) having a reactive functional group has two or four groups containing an epoxy group as the reactive functional group.

6. The optical component bonding composition according to claim 3, wherein the chain siloxane compound (A2) having a reactive functional group has two or more groups containing a cationically polymerizable group as the reactive functional group.

7. The optical component bonding composition according to claim 3, wherein the chain siloxane compound (A2) having a reactive functional group has two or more groups containing an alicyclic epoxy group as the reactive functional group.

8. The optical component bonding composition according to claim 3, wherein the content (total amount) of the cyclic siloxane compound (A1) having a reactive functional group and the chain siloxane compound (A2) having a reactive functional group is 5 to 90 mass %.

9. The optical component bonding composition according to claim 3, wherein the mass ratio of the cyclic siloxane compound (A1) having a reactive functional group to the chain siloxane compound (A2) having a reactive functional group is 90:10 to 5:

95.

10. The optical component bonding composition according to claim 1 or 2, wherein the retention rate (%) calculated by the following formula is 72.0% or more. The following transmittances are values ​​measured at 25°C. Retention rate (%) = Transmittance (%) of cured product (after heat treatment) at a wavelength of 425 nm / Transmittance (%) of cured product (initial) at a wavelength of 425 nm × 100 Cured product (initial): Cured product one hour after completion of curing of the composition Cured product (after heat treatment): Cured product after the cured product (initial) is reflowed five times at 260°C in a nitrogen atmosphere, and then exposed to 200°C in an air atmosphere for four hours and heat-treated 11. The optical component bonding composition according to claim 1 or 2, wherein the content of the filler (C) is 5 to 90 mass %.

12. The optical part bonding composition according to claim 1 or 2, wherein the filler (C) has an average particle size of 0.1 to 5.0 μm.

13. The adhesive composition for optical parts according to claim 1 or 2, which is used to fix an optical fiber in a groove formed in an optical waveguide element.

14. The adhesive composition for optical parts according to claim 1 or 2, which is used for optically coupling an optical fiber to an optical waveguide element.

15. The adhesive composition for optical components according to claim 1 or 2, which is used to simultaneously fix an optical fiber to a groove formed in an optical waveguide element and optically couple the optical fiber to the optical waveguide element.

16. A cured product of the adhesive composition for optical parts according to claim 1 or 2.

17. An optical fiber array comprising: an adhesive composition for optical components according to claim 1 or 2; an optical fiber; and an optical waveguide element, wherein the optical fiber is optically coupled to the optical waveguide element by the adhesive composition for optical components.

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