Resin compositions, resin films, films, film sets, optical waveguides, optoelectronic composite substrates, and electronic components

Abstract

To provide a resin composition capable of improving embedding properties while suppressing a decrease in light transmittance.SOLUTION: The resin composition can be used in an optical waveguide cladding and contains a cyclic olefin resin (A). The cyclic olefin resin (A) contains a structural unit (a) and a structural unit (b). The structural unit (a) is a structural unit represented by formula (a-1). The structural unit (b) is one or more selected from the group consisting of a structural unit represented by formula (b-1), a structural unit represented by formula (b-2), and a structural unit represented by formula (b-3).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition, a resin film, a film, a film set, an optical waveguide, an optoelectronic composite substrate, and an electronic component.

Background Art

[0002] In recent years, in information communication devices, there has been a demand for components that can achieve more advanced information communication, such as increased information capacity and higher information communication speed. As one of such components, an optoelectronic composite substrate has been studied.

[0003] An optoelectronic composite substrate includes, for example, a substrate on which an optical waveguide is provided. Examples of technologies related to optoelectronic composite substrates include the technologies described in Patent Documents 1 and 2.

[0004] Patent Document 1 describes an optoelectronic hybrid substrate including a flexible circuit board having mounting pads formed on the surface of an insulating layer, an element mounted on the mounting pads, and an optical waveguide laminated on the back surface side of the insulating layer. The flexible circuit board is a flexible double-sided circuit board having electrical wiring formed on the back surface of the insulating layer. A metal reinforcing layer is formed by plating at least on a portion corresponding to the mounting pads among the electrical wiring on the back surface side, and the optical waveguide is in contact with the metal reinforcing layer. According to the optoelectronic hybrid substrate described in Patent Document 1, a metal reinforcing layer is adhered to the insulating layer of the flexible circuit board without an adhesive layer, and the metal reinforcing layer can provide an optoelectronic hybrid substrate in which an element is properly mounted while suppressing deformation due to a pressing load during element mounting.

[0005] Patent Document 1 describes preparing a substrate in which copper foils 21 are formed on the front and back surfaces of an insulating layer 1 made of a resin such as polyimide, and forming through-holes 1a and via holes 1b for light paths in the substrate (see paragraph 0023 of Patent Document 1). And a flexible double-sided circuit board E on which a metal reinforcing layer M is formed is described (see paragraph 0028 of Patent Document 1). The flexible double-sided circuit board E includes the above substrate. Furthermore, Patent Document 1 describes forming an underclad layer 6 in a state of abutting on a metal reinforcing layer M that covers the back-side electrical wiring 2B on the back side of the flexible double-sided circuit board E, and describes that examples of the molding material of the underclad layer 6 include photosensitive resin, thermosetting resin, etc. (see paragraph 0029 of Patent Document 1). According to FIGS. 4 to 6 of Patent Document 1, it can be understood that the molding material of the underclad layer 6 is filled in the recesses formed in the flexible double-sided circuit board E on which the metal reinforcing layer M is formed.

[0006] Patent Document 2 describes an optoelectronic wiring board in which a rigid part in which conductor circuits and insulating layers are laminated on both sides of a substrate and one or more bendable flex parts are integrated, and external connection terminals for mounting an optical element and / or a package substrate on which an optical element is mounted are formed in the rigid part, and an optoelectronic wiring board characterized in that optical wiring is formed in at least one of the flex parts is described. According to the optoelectronic wiring board of Patent Document 2, it is described that large-capacity information processing and high-speed information processing can be suitably performed without increasing the size of the wiring board.

[0007] The rigid part described in Patent Document 2 has an optical signal passing region formed therein, and it is described that the optical signal passing region is filled with a resin composition inside (see claims 4 and 5 of Patent Document 2). Furthermore, it is described that the optical signal passing region is formed so as to penetrate all the substrates and insulating layers constituting the rigid part (see claim 6 of Patent Document 2).

[0008] Furthermore, Patent Document 2 describes a substrate 221 consisting of an optical waveguide film 250 and a surrounding resin layer (insulating layer) 221a, and it is stated that the resin layer 221a constitutes part of the optical signal transmission regions 242a and 242b (see paragraph 0033 of Patent Document 2). [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2014-238455 [Patent Document 2] Japanese Patent Publication No. 2006-140233 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] As described in Patent Documents 1 and 2, in the conventional technology relating to optoelectronic composite substrates, there is a known optoelectronic composite substrate in which a resin composition is filled into recesses and vias formed in the substrate.

[0011] One example of a manufacturing process for an optoelectronic composite substrate is the process of integrating a substrate with vias formed on it with a film for optical waveguide cladding. In this process, the vias formed on the substrate need to be embedded by the optical waveguide cladding. That is, resin compositions that can be used for optical waveguide cladding are required to have properties that allow the resin composition to be sufficiently embedded in the vias (hereinafter, "embedding properties" refers to the property of how well the resin composition that can be used for optical waveguide cladding can be embedded in the vias).

[0012] Furthermore, resin compositions that can be used in optical waveguide cladding are also required to have high light transmittance.

[0013] This invention was made in view of the above circumstances, and provides a resin composition that can improve embeddability while suppressing a decrease in light transmittance. [Means for solving the problem]

[0014] The present invention provides the following resin compositions, resin films, films, film sets, optical waveguides, optoelectronic composite substrates, and electronic components.

[0015] [1] A resin composition that can be used in optical waveguide cladding, Contains a cyclic olefin resin (A), The cyclic olefin resin (A) comprises structural unit (a) and structural unit (b), The aforementioned structural unit (a) is a structural unit represented by the following formula (a-1), A resin composition in which the structural unit (b) is one or more selected from the group consisting of the structural unit represented by the following formula (b-1), the structural unit represented by the following formula (b-2), and the structural unit represented by the following formula (b-3). [ka] (In formula (a-1), R 1 , R 2 , R 3 and R 4 Each of these independently represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms. [ka] (In formula (b-1), R 11 (This represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms.) [ka] [ka] (In formula (b-3), R 21 and R 22 Each of these independently represents a hydrogen atom or an organic group with 1 to 30 carbon atoms. [2] The resin composition according to [1], wherein the content of the structural unit (a) in the cyclic olefin resin (A) is 10 mol% or more and 70 mol% or less when the total amount of all structural units in the cyclic olefin resin (A) is 100 mol%. [3] The resin composition according to [1] or [2], wherein the refractive index of the cyclic olefin resin (A) is 1.45 or more and 1.55 or less. [4] The resin composition according to any one of [1] to [3], wherein the content of the cyclic olefin resin (A) in the resin composition is 20 parts by mass or more and 80 parts by mass or less, when the total content of resin components in the resin composition is 100 parts by mass. [5] The resin composition according to any one of [1] to [4], further comprising a compound (B) having a cyclic ether structure. [6] The resin composition according to [5], wherein the compound (B) having a cyclic ether structure comprises at least one or more selected from the group consisting of epoxy compounds and oxetane compounds. [7] The resin composition according to [5] or [6], wherein the compound (B) having the cyclic ether structure contains an alicyclic structure within the molecule. [8] The resin composition according to any one of [5] to [7], wherein the compound (B) having the cyclic ether structure contains two or more cyclic ether structures within the molecule. [9] The resin composition according to any one of [5] to [8], wherein the compound (B) having the cyclic ether structure is liquid at 23°C.

[10] The resin composition according to any one of [5] to [9], wherein the refractive index of the compound (B) having the cyclic ether structure is 1.45 or more and 1.55 or less.

[11] The resin composition according to any one of [5] to

[10] , wherein the content of the compound (B) having the cyclic ether structure in the resin composition is 20 parts by mass or more and 80 parts by mass or less, when the total content of resin components in the resin composition is 100 parts by mass.

[12] A resin composition according to any one of the above [1] to

[11] , further comprising a curing agent (C).

[13] The resin composition according to

[12] , wherein the curing agent (C) comprises a cationic polymerization initiator.

[14] The resin composition according to

[13] , wherein the cationic polymerization initiator comprises a photocationic polymerization initiator.

[15] The resin composition according to

[13] or

[14] , wherein the cationic polymerization initiator comprises a thermal cationic polymerization initiator.

[16] The resin composition according to any one of

[12] to

[15] , wherein the curing agent (C) comprises an imidazole compound.

[17] The resin composition according to any one of

[12] to

[16] , wherein the content of the curing agent (C) contained in the resin composition is 0.05 parts by mass or more and 10.0 parts by mass or less, when the total content of resin components in the resin composition is 100 parts by mass.

[18] The resin composition according to any one of [1] to

[17] , wherein the refractive index of the resin composition is 1.47 or more and 1.55 or less.

[19] A resin film comprising the resin composition described in any of the above [1] to

[18] , The aforementioned resin film is a resin film having a light transmittance of 85% or more for a wavelength of 850 nm.

[20] The resin film is the resin film according to

[19] , wherein the thickness is 1 μm or more and 150 μm or less. [twenty one] A film that can be used in optical waveguide cladding, A film comprising a resin layer formed from any of the resin compositions described in [1] to

[18] above. [twenty two] Furthermore, it includes a base film, The film according to

[21] , having the resin layer on the base film. [twenty three] The film according to

[22] , wherein the resin constituting the base film comprises at least one or more selected from the group consisting of polyimide and polyethylene terephthalate. [twenty four] The film according to any one of

[21] to

[23] , wherein the film is a dry film. [twenty five] A film set that can be used in optical waveguide cladding, Including a first film and a second film, A film set in which at least one of the first film and the second film is a film according to any of

[21] to

[24] above.

[26] An optical waveguide in which a first cladding layer, a core layer, and a second cladding layer are stacked in this order, An optical waveguide in which at least one of the first cladding layer and the second cladding layer comprises the resin composition described in any of [1] to

[18] above.

[27] circuit board and An optoelectronic composite substrate comprising the optical waveguide described in

[26] provided on the substrate.

[28] An electronic component comprising the optoelectronic composite substrate described in

[27] above. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a resin composition that can improve embeddability while suppressing a decrease in light transmittance. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic cross-sectional view showing an example of the structure of the optoelectronic composite substrate of this embodiment. [Modes for carrying out the invention]

[0018] Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are simplified diagrams and do not correspond to the actual dimensional ratios. Unless otherwise specified, the numerical range "A~B" represents A or greater and B or less.

[0019] Figure 1 is a schematic cross-sectional view showing an example of the structure of a photoelectric composite substrate according to this embodiment. As shown in Figure 1, the optoelectronic composite substrate 200 has an optical waveguide 100 provided on a substrate 110. The optical waveguide 100 is constructed by stacking a first cladding layer 20, a core layer 30, and a second cladding layer 40 in that order. The optical waveguide 100 has a mirror 50 on the light-emitting side and a mirror 60 on the light-receiving side. Vias 140 (140a, 140b) are formed on the substrate 110 (note that the vias 140 shown in Figure 1 are embedded by the first cladding layer 20). A light-emitting element 120 and a light-receiving element 130 are provided on the side of the substrate 110 opposite to the optical waveguide 100 side.

[0020] The light propagation path in the photoelectric composite substrate 200 will be specifically explained using Figure 1. Light emitted from the light-emitting part of the light-emitting element 120 passes through via 140a formed in the substrate 110, is incident on the mirror 50 on the light-emitting element side, is transmitted through the core layer 30, is then incident on the mirror 60 on the photodetector side, passes through via 140b formed in the substrate 110, and is incident on the photodetector 130. The arrows in Figure 1 schematically represent the propagation of light.

[0021] When providing an optical waveguide 100 on a substrate 110, for example, the process includes laminating the substrate 110 on which vias 140 are formed with a film for forming a first cladding layer 20, and then integrating them by heating and pressurizing. In the integrating process, it is necessary to embed the vias 140 with the first cladding layer 20.

[0022] Our investigations have shown that with conventional materials for forming optical waveguide cladding, the optical waveguide cladding cannot be sufficiently embedded in the vias formed on the substrate, which can result in depressions on the side of the optical waveguide cladding opposite to the substrate (i.e., the core layer side of the optical waveguide cladding) or voids occurring within the vias. We have also found that when these depressions or voids occur in the optoelectronic composite substrate, optical loss occurs at the interface between the depressions and voids. In other words, resin compositions that can be used in optical waveguide cladding are required to have properties that allow the resin composition to be sufficiently embedded in vias.

[0023] Furthermore, as described above, the first cladding layer 20 embedded in the via 140 serves as a light propagation path. Therefore, resin compositions that can be used for optical waveguide cladding are required to have high light transmittance (for example, light transmittance at a wavelength of 850 nm).

[0024] This invention was made in view of the above circumstances, and provides a resin composition that can improve embeddability while suppressing a decrease in light transmittance.

[0025] Furthermore, according to the present invention, it is possible to provide an optoelectronic composite substrate that can suppress propagation loss.

[0026] [Resin composition] The resin composition of this embodiment is a resin composition that can be used in optical waveguide cladding and comprises a cyclic olefin resin (A), the cyclic olefin resin (A) comprising structural unit (a) and structural unit (b), wherein structural unit (a) is a structural unit represented by formula (a-1), and structural unit (b) is one or more selected from the group consisting of structural units represented by formula (b-1), formula (b-2), and formula (b-3).

[0027] [ka]

[0028] In formula (a-1), R 1 , R 2 , R 3 and R 4 each independently represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms.

[0029]

Chemical formula

[0030] In formula (b-1), R 11 represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms.

[0031]

Chemical formula

[0032]

Chemical formula

[0033] In formula (b-3), R 21 and R 22 each independently represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.

[0034] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the resin composition of the present embodiment is preferably 1.55 or less, more preferably 1.54 or less, still more preferably 1.53 or less, and even more preferably 1.52 or less. The lower limit is not particularly limited, and for example, it may be 1.47 or more, or 1.48 or more. The refractive index of the resin composition means the refractive index measured under the conditions of 23 °C and 589 nm using an Abbe refractometer for the resin film composed of the resin composition. The resin film composed of the resin composition can be produced, for example, by applying and drying the resin composition on a base film as described in the method of the examples.

[0035] From the viewpoint of further improving the optical propagation efficiency of the optical waveguide, the light transmittance of the resin composition of this embodiment for a wavelength of 850 nm is preferably 85% or more, more preferably 90% or more, more preferably 95% or more, more preferably 97% or more, and more preferably 98% or more. The light transmittance of a resin composition at a wavelength of 850 nm refers to the value of light transmittance measured by an ultraviolet-visible spectrophotometer for a resin film made of a resin composition with a thickness of 25 μm. A resin film consisting of a resin composition with a thickness of 25 μm can be produced, for example, by coating and drying the resin composition on a substrate film, as described in the examples.

[0036] The shape of the resin composition in this embodiment is not particularly limited and may include, for example, a film, a membrane, a varnish, a sheet, or the like.

[0037] The following describes each component of the resin composition of this embodiment.

[0038] <Cyclic olefin resin (A)> The resin composition of this embodiment includes a cyclic olefin resin (A). The cyclic olefin resin (A) includes structural unit (a) and structural unit (b).

[0039] In the cyclic olefin resin (A), structural unit (a) is the structural unit represented by formula (a-1).

[0040] [ka]

[0041] In formula (a-1), R 1 , R 2 , R 3 and R 4 Each of these independently represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms. In formula (a-1), the organic group having 1 to 30 carbon atoms is preferably an organic group having 1 to 25 carbon atoms, more preferably an organic group having 1 to 20 carbon atoms, and even more preferably an organic group having 1 to 15 carbon atoms.

[0042] In formula (a-1), R 1 , R 2 , R 3 and R 4 Examples of organic groups constituting the compound include at least one selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkalyl groups, cycloalkyl groups, carboxyl groups, and heterocyclic organic groups. Examples of alkyl groups include at least one selected from the group consisting of methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, and dodecyl group. Examples of alkenyl groups include at least one selected from the group consisting of allyl groups, pentenyl groups, and vinyl groups. Examples of alkynyl groups include the ethynyl group. Examples of alkylidene groups include at least one selected from the group consisting of methylidene groups and ethylidene groups. Examples of aryl groups include at least one selected from the group consisting of phenyl, naphthyl, and anthracenyl groups. Examples of aralkyl groups include at least one selected from the group consisting of benzyl groups and phenethyl groups. Examples of the alkalyl group include at least one selected from the group consisting of tolyl groups and xylyl groups. Examples of cycloalkyl groups include at least one selected from the group consisting of adamantyl, cyclopentyl, cyclohexyl, and cyclooctyl groups. Examples of organic groups having heterocycles include epoxy groups and organic groups having oxetanyl groups.

[0043] R 1 , R 2 , R 3 and R 4 In the organic groups constituting the compound, organic groups having alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkalil groups, cycloalkyl groups, carboxyl groups, and heterocyclic organic groups may have one or more hydrogen atoms substituted with halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0044] From the viewpoint of further improving the film-forming properties of the resin composition, R 1 , R 2 , R 3 and R 4 It is preferable that at least one selected from the group consisting of is an alkyl group. Furthermore, from the viewpoint of further improving the heat resistance and strength of the cured resin composition, R 1 , R 2 , R 3 and R 4 Preferably, at least one selected from the group consisting of is at least one selected from the group consisting of organic groups having a carboxyl group and organic groups having a heterocycle.

[0045] Among these, in equation (a-1), R 1 , R 2 , R 3 and R 4Each of these terms independently preferably represents an organic group having a hydrogen atom, a carboxyl group, or a heterocycle; more preferably represents an organic group having a hydrogen atom, a carboxyl group, or an epoxy group; even more preferably represents an organic group having 1 to 8 carbon atoms having a hydrogen atom, a carboxyl group, or an epoxy group; and still more preferably represents an organic group having 1 to 4 carbon atoms having a hydrogen atom, a carboxyl group, or an epoxy group.

[0046] In the cyclic olefin resin (A), the structural unit (b) is one or more selected from the group consisting of the structural unit represented by formula (b-1), the structural unit represented by formula (b-2), and the structural unit represented by formula (b-3).

[0047] The structural unit represented by equation (b-1) is shown below.

[0048] [ka]

[0049] In formula (b-1), R 11 represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms. In formula (b-1), the organic group having 1 to 30 carbon atoms is preferably an organic group having 1 to 25 carbon atoms, more preferably an organic group having 1 to 20 carbon atoms, and even more preferably an organic group having 1 to 15 carbon atoms.

[0050] In formula (b-1), R 11 Examples of organic groups constituting the compound include at least one selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkalil groups, and cycloalkyl groups. R 11 Specific examples of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, and cycloalkyl groups as constituent organic groups are R 1, R 2 , R 3 and R 4 This is similar to the specific example described for the organic groups that make up the compound.

[0051] R 11 In the organic group constituting the compound, one or more hydrogen atoms may be substituted by halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0052] Among these, in equation (b-1), R 11 R preferably represents a hydrogen atom, an alkyl group, or a cycloalkyl group. 11 It is more preferable that represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl group having 1 to 20 carbon atoms, and even more preferable that represents a hydrogen atom, a dodecyl group, or a cyclohexyl group.

[0053] The structural unit shown in equation (b-2) is as follows.

[0054] [ka]

[0055] The structural unit shown in equation (b-3) is as follows.

[0056] [ka]

[0057] In formula (b-3), R 21 and R 22 Each of these independently represents a hydrogen atom or an organic group with 1 to 30 carbon atoms. In formula (b-3), the organic group having 1 to 30 carbon atoms is preferably an organic group having 1 to 25 carbon atoms, more preferably an organic group having 1 to 20 carbon atoms, and even more preferably an organic group having 1 to 15 carbon atoms.

[0058] In formula (b-3), R 21and R 22 Examples of organic groups constituting the compound include at least one selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkalyl groups, cycloalkyl groups, groups having acryloyl groups, and groups having methacryloyl groups. R 21 and R 22 Specific examples of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, and cycloalkyl groups as constituent organic groups are R 1 , R 2 , R 3 and R 4 This is similar to the specific example described for the organic groups that make up the compound.

[0059] R 21 and R 22 In the organic group constituting the compound, one or more hydrogen atoms may be substituted by halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0060] Among these, in equation (b-3), R 21 and R 22 Each of these elements preferably independently represents a hydrogen atom or an alkyl group, and more preferably a hydrogen atom or an n-butyl group.

[0061] Equation (b-3) is R 21 is a hydrogen atom, and R 22 It is preferable that R is an organic group having 1 to 30 carbon atoms. 21 is a hydrogen atom, and R 22 It is more preferable that R is an alkyl group. 21 is a hydrogen atom, and R 22 It is more preferable that R is an alkyl group having 1 to 10 carbon atoms. 21 is a hydrogen atom, and R 22 It is even more preferable that it is an n-butyl group.

[0062] The cyclic olefin resin (A) may contain structural unit (a) and structural units other than structural unit (b). Other structural units include, for example, structural units derived from compounds having ethylenic double bonds. Examples of compounds having an ethylenic double bond include α-olefins with 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene; 1,4 At least one selected from the group consisting of -hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene, and other non-conjugated dienes; acrylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, and 2-hydroxyethyl(meth)acrylic acid; maleic acids such as maleic acid, maleic anhydride, dimethylmaleic acid, diethylmaleic acid, and dibutylmaleic acid; and vinyl ethers such as ethyl oxetane vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, and allyl vinyl ether.

[0063] The content of structural unit (a) in the cyclic olefin resin (A) is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 30 mol% or more, even more preferably 35 mol% or more, even more preferably 40 mol% or more, and preferably 70 mol% or less, more preferably 65 mol% or less, and even more preferably 60 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%.

[0064] The content of structural unit (b) in the cyclic olefin resin (A) is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 30 mol% or more, even more preferably 35 mol% or more, even more preferably 40 mol% or more, and preferably 70 mol% or less, more preferably 65 mol% or less, and even more preferably 60 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%.

[0065] The total content of structural unit (a) and structural unit (b) in the cyclic olefin resin (A) is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 65 mol% or more, and for example, 100 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%.

[0066] The refractive index of the cyclic olefin resin (A) is preferably 1.55 or less, more preferably 1.53 or less, and even more preferably 1.52 or less, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide, and the lower limit is not particularly limited, but may be, for example, 1.45 or more, or 1.48 or more. The refractive index of cyclic olefin resin (A) refers to the refractive index measured at 23°C and 589 nm using an Abbe refractometer.

[0067] The weight-average molecular weight (Mw) of the cyclic olefin resin (A) is preferably 4,000 or more, more preferably 5,000 or more, and even more preferably 6,000 or more, and from the viewpoint of further improving solubility in organic solvents, it is preferably 20,000 or less, more preferably 18,000 or less, and even more preferably 16,000 or less. The weight-average molecular weight (Mw) of cyclic olefin resin (A) can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0068] The content of the cyclic olefin resin (A) in the resin composition of this embodiment is preferably 20 parts by mass or more, more preferably 23 parts by mass or more, even more preferably 25 parts by mass or more, and even more preferably 28 parts by mass or more, from the viewpoint of further improving embeddability while suppressing a decrease in light transmittance, and also preferably 100 parts by mass or less, more preferably 80 parts by mass or less, more preferably 75 parts by mass or less, even more preferably 70 parts by mass or less, and even more preferably 65 parts by mass or less, from the viewpoint of further improving embeddability while suppressing a decrease in light transmittance.

[0069] The content of the cyclic olefin resin (A) in the resin composition of this embodiment is preferably 5% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, and even more preferably 28% by mass or more, from the viewpoint of further improving embeddability while suppressing a decrease in light transmittance, and also preferably less than 100% by mass, more preferably 80% by mass or less, even more preferably 75% by mass or less, even more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less, from the viewpoint of further improving embeddability while suppressing a decrease in light transmittance.

[0070] The cyclic olefin resin (A) can be produced, for example, by known methods, and more specifically, by polymerizing monomers capable of forming each structural unit in any way. Here, examples of monomers capable of forming the structural unit shown in formula (a-1) include 2-norbornene, methylglycidyl ether norbornene, and 5-norbornene-2-carboxylic acid. Examples of monomers capable of forming the structural unit shown in formula (b-1) include maleimide and N-cyclohexylmaleimide. Examples of monomers capable of forming the structural unit shown in formula (b-2) include maleic anhydride. Examples of monomers capable of forming the structural unit shown in formula (b-3) include 1-butyl hydrogen maleate and ethyl hydrogen maleate.

[0071] The cyclic olefin resin (A) may be one type of cyclic olefin resin, or it may contain two or more types of cyclic olefin resins.

[0072] <Compound having a cyclic ether structure (B)> From the viewpoint of further improving embeddability, the resin composition of this embodiment preferably further contains a compound (B) having a cyclic ether structure. Here, the compound (B) having a cyclic ether structure in this embodiment can be a monomer, oligomer, or polymer in general, and its molecular weight and molecular structure are not particularly limited. Furthermore, in this specification, the resin component in the resin composition also includes the compound (B) having a cyclic ether structure.

[0073] The compound (B) having a cyclic ether structure preferably includes at least one or more compounds selected from the group consisting of epoxy compounds and oxetane compounds.

[0074] Compound (B) having a cyclic ether structure preferably contains an alicyclic structure within its molecule. Here, compound (B) having a cyclic ether structure containing an alicyclic structure means that it contains an alicyclic structure in addition to the cyclic ether structure. However, the alicyclic structure in this embodiment includes a fused ring structure in which a cyclic ether and an aliphatic ring are fused, and a spiro-ring structure in which a cyclic ether and an aliphatic ring are bonded by a spiro-bonding atom. The number of members in the alicyclic structure is not particularly limited, but it is preferably 4-membered to 10-membered rings, more preferably 4-membered to 8-membered rings, even more preferably 5-membered or 6-membered rings, and even more preferably 6-membered rings.

[0075] Compound (B) having a cyclic ether structure preferably contains two or more cyclic ether structures within the molecule, and more preferably contains two or three cyclic ether structures within the molecule.

[0076] Compound (B), which has a cyclic ether structure, is preferably liquid at 23°C from the viewpoint of ease of handling when manufacturing the resin composition.

[0077] The refractive index of compound (B) having a cyclic ether structure is preferably 1.55 or less, more preferably 1.53 or less, and even more preferably 1.52 or less, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide, and the lower limit is not particularly limited, but may be, for example, 1.45 or more, or 1.48 or more. The refractive index of compound (B) having a cyclic ether structure refers to the refractive index measured at 23°C and 589 nm using an Abbe refractometer.

[0078] The content of compound (B) having a cyclic ether structure in the resin composition of this embodiment is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, even more preferably 35 parts by mass or more, and preferably 80 parts by mass or less, more preferably 75 parts by mass or less, when the total content of resin components in the resin composition is 100 parts by mass, from the viewpoint of further improving embeddability.

[0079] Compound (B) having a cyclic ether structure may be a compound having one cyclic ether structure, or it may contain two or more compounds having cyclic ether structures.

[0080] <Hardening agent (C)> The resin composition of this embodiment preferably further contains a curing agent (C). Examples of the curing agent (C) include at least one selected from the group consisting of thermal polymerization initiators, photopolymerization initiators, amine compounds, and the like.

[0081] The curing agent (C) preferably contains a cationic polymerization initiator. Examples of cationic polymerization initiators include photocatalytic cationic polymerization initiators and thermal cationic polymerization initiators.

[0082] The curing agent (C) contains a cationic polymerization initiator, and preferably contains a photocationic polymerization initiator as the cationic polymerization initiator. The photocationic polymerization initiator includes, for example, a sulfonium salt type polymerization initiator, an iodonium salt type polymerization initiator, and preferably a sulfonium salt type polymerization initiator, more preferably a triarylsulfonium salt type polymerization initiator, and even more preferably a triphenylsulfonium salt type polymerization initiator.

[0083] The curing agent (C) contains a cationic polymerization initiator, and preferably contains a thermal cationic polymerization initiator as the cationic polymerization initiator. The thermal cationic polymerization initiator includes, for example, a sulfonium salt type polymerization initiator and an iodonium salt type polymerization initiator, and preferably includes a sulfonium salt type polymerization initiator.

[0084] The curing agent (C) preferably contains an imidazole compound. An imidazole compound refers to a compound containing an imidazole ring structure, for example, a compound in which the hydrogen atoms of imidazole are replaced with hydrocarbon groups or the like.

[0085] The amount of curing agent (C) contained in the resin composition of this embodiment is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, and preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, and even more preferably 6.0 parts by mass or less, when the total amount of resin components in the resin composition is 100 parts by mass.

[0086] When the curing agent (C) includes at least one selected from the group consisting of photocationic polymerization initiators and thermal cationic polymerization initiators, the amount of curing agent (C) contained in the resin composition of this embodiment is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, and preferably 1.0 part by mass or less, more preferably 0.7 parts by mass or less, and even more preferably 0.5 parts by mass or less, when the total amount of resin components in the resin composition is 100 parts by mass.

[0087] When the curing agent (C) contains an imidazole compound, the amount of curing agent (C) contained in the resin composition of this embodiment is preferably 1.0 part by mass or more, more preferably 2.0 parts by mass or more, even more preferably 4.0 parts by mass or more, and preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, and even more preferably 6.0 parts by mass or less, when the total amount of resin components in the resin composition is 100 parts by mass.

[0088] The curing agent (C) in this embodiment may be one type of curing agent, or it may contain two or more types of curing agents.

[0089] <Surfactant (D)> The resin composition of this embodiment preferably further contains a surfactant (D) from the viewpoint of further improving embedding properties. The surfactant (D) includes, for example, a silicone-based surfactant, a fluorine-based surfactant, and preferably a silicone-based surfactant. The surfactant (D) in this embodiment may be one type of surfactant or may contain two or more types of surfactants.

[0090] The amount of surfactant (D) contained in the resin composition of this embodiment is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.07 parts by mass or more, and preferably 3.0 parts by mass or less, more preferably 1.0 part by mass or less, even more preferably 0.7 parts by mass or less, even more preferably 0.5 parts by mass or less, and even more preferably 0.3 parts by mass or less, when the total amount of resin components in the resin composition is 100 parts by mass.

[0091] <Organic solvent (E)> The resin composition of this embodiment may contain an organic solvent (E). When the resin composition of this embodiment contains an organic solvent (E), it can be made into a varnish-like resin composition.

[0092] Examples of the organic solvent (E) in this embodiment include acetone, methyl ethyl ketone, methyl amyl ketone, toluene, propylene glycol monomethyl ether, propylene glycol methyl ethyl ether, propylene glycol dimethyl ether, propylene glycol 1-monomethyl ether 2-acetate, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, benzyl alcohol, propylene carbonate, ethylene glycol diacetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate, dipropylene glycol methyl-n-propyl ether, butyl acetate, γ-butyrolactone, methyl lactate, ethyl lactate, butyl lactate, and the like. The organic solvent (E) in this embodiment may be one type of organic solvent, or it may contain two or more types of organic solvents.

[0093] When the resin composition of this embodiment contains an organic solvent (E), the concentration of total solids (non-volatile components) in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 35% by mass or more, from the viewpoint of appropriately controlling the viscosity of the resin composition, and preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, from the viewpoint of sufficiently dissolving each component in the resin composition.

[0094] <Other ingredients> The resin composition of this embodiment may further contain, for example, a curing aid, a leveling agent, a colorant, a preservative stabilizer, a plasticizer, a filler, inorganic particles, a degradation inhibitor, a wettability improver, an antistatic agent, and the like. The amount of other components is appropriate.

[0095] The total content of the cyclic olefin resin (A) and the compound having a cyclic ether structure (B) in the resin composition of this embodiment is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 98% by mass or more, from the viewpoint of further improving embeddability while suppressing a decrease in light transmittance, when the total content of resin components in the resin composition is set to 100% by mass. The upper limit of the total content is not particularly limited, but for example, it is 100% by mass or less. The total content of the cyclic olefin resin (A) and the compound having a cyclic ether structure (B) in the resin composition of this embodiment is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, even more preferably 50% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 92% by mass or more, and the upper limit is not particularly limited, but for example it is less than 100% by mass and 99% by mass or less.

[0096] The total content of the cyclic olefin resin (A), the compound having a cyclic ether structure (B), and the curing agent (C) in the resin composition of this embodiment is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, even more preferably 50% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, and the upper limit is not particularly limited, but for example it is 100% by mass or less.

[0097] [Method for producing resin compositions] The resin composition of this embodiment can be obtained, for example, by mixing each component. The film-like resin composition of this embodiment can be obtained, for example, by applying a varnish-like resin composition onto a base film and drying it.

[0098] [Resin film] The resin film of this embodiment is a resin film made of the resin composition of this embodiment. The resin film of this embodiment includes not only the resin film itself, but also resin films formed on a substrate film, etc.

[0099] From the viewpoint of further improving the optical propagation efficiency of the optical waveguide, the light transmittance of the resin film in this embodiment for a wavelength of 850 nm is preferably 85% or more, more preferably 90% or more, more preferably 95% or more, more preferably 97% or more, and more preferably 98% or more. The light transmittance of a resin film at a wavelength of 850 nm can be measured using an ultraviolet-visible spectrophotometer.

[0100] The thickness of the resin film in this embodiment is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and even more preferably 8 μm or more, from the viewpoint of further improving embedding properties, and is preferably 150 μm or less, more preferably 130 μm or less, even more preferably 100 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, and even more preferably 30 μm or less, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide.

[0101] The resin film of this embodiment can be obtained, for example, by a known method of forming a coating film using a varnish-like resin composition of this embodiment as a raw material.

[0102] [film] The film of this embodiment comprises a resin layer formed from the resin composition of this embodiment. The film in this embodiment is preferably a dry film.

[0103] The thickness of the film in this embodiment is preferably 10 μm or more, more preferably 30 μm or more, even more preferably 50 μm or more, even more preferably 60 μm or more, even more preferably 80 μm or more, and preferably 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less, from the viewpoint of further improving the handling of the film.

[0104] The thickness of the resin layer in this embodiment is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and even more preferably 8 μm or more. Furthermore, from the viewpoint of further improving the optical propagation efficiency of the optical waveguide, it is preferably 150 μm or less, more preferably 130 μm or less, even more preferably 100 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, and even more preferably 30 μm or less.

[0105] The film of this embodiment preferably further comprises a base film, and a resin layer is provided on the base film. For example, a resin film can be used as the base film. The resin constituting the base film is not particularly limited, but it is preferable to include at least one or more resins selected from the group consisting of polyimide and polyethylene terephthalate.

[0106] The thickness of the base film in this embodiment is preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and even more preferably 40 μm or less, from the viewpoint of further improving the handling of the film.

[0107] The base film of this embodiment may be subjected to surface treatments such as antistatic treatment and mold release treatment.

[0108] The film of this embodiment may further include a cover film. Preferably, the cover film is provided in direct contact with the resin layer. When the film of this embodiment includes a base film, it is preferable that the cover film is provided on the side of the resin layer opposite to the base film. The cover film is not particularly limited, but for example, an OPP cover film can be used.

[0109] The film of this embodiment can be obtained, for example, by applying and drying the varnish-like resin composition of this embodiment onto a base film. Methods of application include direct application using various coating devices such as pin coaters, die coaters, comma coaters, and curtain coaters, as well as printing methods such as screen printing.

[0110] [Film Set] The film set of this embodiment includes a first film and a second film, wherein at least one of the first film and the second film is the film of this embodiment. In this embodiment, it is preferable that both the first film and the second film in the film set are the films of this embodiment.

[0111] [Optical waveguide] The optical waveguide of this embodiment will be explained with reference to Figure 1. The optical waveguide 100 of this embodiment is an optical waveguide in which a first cladding layer 20, a core layer 30, and a second cladding layer 40 are stacked in this order, and at least one of the first cladding layer 20 and the second cladding layer 40 contains the resin composition of this embodiment. In this embodiment, it is preferable that both the first cladding layer 20 and the second cladding layer 40 of the optical waveguide contain the resin composition of this embodiment.

[0112] When the optical waveguide 100 is provided on the substrate 110, it is preferable that the first cladding layer 20 is on the substrate 110 side. When the first cladding layer 20 is on the substrate 110 side, the preferred thicknesses of the first cladding layer 20 and the second cladding layer 40 are as follows. The thickness of the first cladding layer 20 is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, even more preferably 8 μm or more, even more preferably 10 μm or more, even more preferably 15 μm or more, and even more preferably 20 μm or more, and from the viewpoint of further improving the optical propagation efficiency of the optical waveguide, it is preferably 150 μm or less, more preferably 100 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, and even more preferably 30 μm or less. The thickness of the second cladding layer 40 is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, even more preferably 8 μm or more, and preferably 150 μm or less, more preferably 100 μm or less, even more preferably 70 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, even more preferably 30 μm or less, and even more preferably 20 μm or less, from the viewpoint of further suppressing thermal shrinkage of the optical waveguide.

[0113] The material forming the core layer 30 is not particularly limited, but for example, it may be formed from a resin composition. The resin used to form the core layer 30 can be, for example, a resin used for the core of a known optical waveguide, but it is preferable to include a cyclic olefin resin, and more preferably a norbornene resin. The resin composition for forming the core layer 30 may contain antioxidants, photocationic polymerization initiators, and the like.

[0114] The thickness of the core layer 30 is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, even more preferably 20 μm or more, even more preferably 30 μm or more, and preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and even more preferably 50 μm or less.

[0115] The core layer 30 may have a waveguide pattern formed on it. Examples of methods for forming the waveguide pattern include exposure, etching, and replication.

[0116] The optical waveguide 100 may have mirrors formed on it, and may have a mirror 50 on the light-emitting element side and a mirror 60 on the light-receiving element side. One method for forming the mirrors is to form an inclined surface by laser processing or the like.

[0117] In addition to the first cladding layer 20, the core layer 30, and the second cladding layer 40, the optical waveguide 100 may also include other layers, provided that they do not affect the good performance of the optical waveguide 100.

[0118] [Optoelectric composite substrate] The optoelectronic composite substrate of this embodiment will be described with reference to Figure 1. The optoelectronic composite substrate 200 comprises a substrate 110 and an optical waveguide 100 provided on the substrate 110.

[0119] The substrate 110 can be, for example, a printed circuit board or a flexible circuit board, and is preferably a flexible circuit board. The substrate 110 may have vias 140 formed on it.

[0120] The optoelectronic composite substrate 200 may further include a polyimide substrate (not shown) on the side of the second cladding layer 40 opposite to the core layer 30.

[0121] The photoelectric composite substrate 200 may include a light-emitting element 120, a light-receiving element 130, and the like.

[0122] The optoelectronic composite substrate 200 can be obtained, for example, by (i) forming a first cladding layer 20 on a substrate 110, (ii) forming a core layer 30 on the first cladding layer 20, and (iii) forming a second cladding layer 40 on the core layer 30. Methods for forming each layer include, for example, laminating each layer sequentially by rolling the film for each layer using methods such as roll lamination, vacuum roll lamination, flat lamination, vacuum flat lamination, atmospheric pressure pressing, and vacuum pressing.

[0123] [Electronic components] The electronic component of this embodiment includes the photoelectric composite substrate of this embodiment. Examples of electronic components in this embodiment include those found in electronic devices such as mobile phones, game consoles, routers, WDM devices, personal computers, televisions, and home servers.

[0124] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the embodiments described above, and any modifications, improvements, etc., that can achieve the objectives of the present invention are included in the present invention. [Examples]

[0125] The embodiment will be described in detail below based on examples and comparative examples. However, this embodiment is not limited in any way to the descriptions of these examples.

[0126] [Raw materials] First, we will describe the raw materials used in the examples and comparative examples.

[0127] <Synthesis of cyclic olefin resins> (Synthesis of cyclic olefin resin (A-1)) In a reaction vessel of appropriate size equipped with a stirrer and condenser, 470.8 g (5.0 mol) of 2-norbornene, 490.3 g (5.0 mol) of maleic anhydride, and 23.0 g (0.10 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed and dissolved in 1607 g of methyl ethyl ketone and 689 g of toluene. After removing dissolved oxygen from the system by nitrogen bubbling, the vessel was sealed and the reaction was carried out at 70°C for 16 hours. After the resulting solution was cooled to room temperature, it was reprecipitation in a large amount of heptane to obtain a polymer precipitate. Subsequently, the polymer was filtered off using a suction filter, and the powder was further washed with heptane. The mixture was then dried in a dryer at 60°C for 24 hours to obtain cyclic olefin resin (A-1). The weight-average molecular weight (Mw) of the cyclic olefin resin (A-1) was 11,000, as determined by GPC measurement, and the refractive index was 1.51 under conditions of 23°C and 589 nm, as determined by Abbe refractometer measurement. The cyclic olefin resin (A-1) is a resin containing the structural unit represented by formula (a-1) and the structural unit represented by formula (b-2).

[0128] (Synthesis of cyclic olefin resin (A-2)) In a reaction vessel of appropriate size equipped with a stirrer and condenser, 470.8 g (5.0 mol) of 2-norbornene, 860.9 g (5.0 mol) of 1-butyl hydrogen maleate, and 23.0 g (0.10 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed and dissolved in 2213 g of methyl ethyl ketone and 948 g of toluene. After removing dissolved oxygen from the system by nitrogen bubbling, the vessel was sealed and reacted at 70°C for 16 hours. After the resulting solution was cooled to room temperature, it was reprecipitation in a large amount of heptane to obtain a polymer precipitate. Subsequently, the polymer was filtered off using a suction filter, and the powder was further washed with heptane. The mixture was then dried in a dryer at 60°C for 24 hours to obtain cyclic olefin resin (A-2). The weight-average molecular weight (Mw) of the cyclic olefin resin (A-2) was 12,000, as determined by GPC measurement, and the refractive index was 1.51 under conditions of 23°C and 589 nm, as determined by Abbe refractometer measurement. The cyclic olefin resin (A-2) is a resin containing the structural unit represented by formula (a-1) and the structural unit represented by formula (b-3).

[0129] (Synthesis of cyclic olefin resin (A-3)) In a reaction vessel of appropriate size equipped with a stirrer and condenser, 450 g (2.5 mol) of methyl glycidyl ether norbornene, 235 g (2.5 mol) of 2-norbornene, 516.5 g (3.0 mol) of 1-butyl hydrogen maleate, 245 g (2.5 mol) of maleic anhydride, and 23.0 g (0.1 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed and dissolved in 2401 g of methyl ethyl ketone and 1029 g of toluene. Then, dissolved oxygen in the system was removed by nitrogen bubbling, the vessel was sealed, and the reaction was carried out at 70°C for 16 hours. After the resulting solution was cooled to room temperature, it was reprecipitation in a large amount of heptane to obtain a polymer precipitate. Subsequently, the polymer was filtered off using a suction filter, and the powder was further washed with heptane. After drying in a dryer at 60°C for 24 hours, a cyclic olefin resin (A-3) was obtained. The weight-average molecular weight (Mw) of the cyclic olefin resin (A-3) was 6,300, determined by GPC measurement, and the refractive index was 1.51 under conditions of 23°C and 589 nm, determined by Abbe refractometer measurement. The cyclic olefin resin (A-3) is a resin containing the structural unit represented by formula (a-1), the structural unit represented by formula (b-2), and the structural unit represented by formula (b-3).

[0130] (Synthesis of cyclic olefin resin (A-4)) In a reaction vessel of appropriate size equipped with a stirrer and condenser, 345.4 g (2.5 mol) of 5-norbornene-2-carboxylic acid, 355.0 g (2.5 mol) of ethyl oxetane vinyl ether, 242.7 g (2.5 mol) of maleimide, 448.1 g (2.5 mol) of N-cyclohexyl maleimide, and 23.0 g (0.1 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed and dissolved in 2310 g of methyl ethyl ketone and 990 g of toluene. After removing dissolved oxygen from the system by nitrogen bubbling, the vessel was sealed and reacted at 70°C for 16 hours. The resulting solution was cooled to room temperature and then reprecipitation in a large amount of heptane to obtain a polymer precipitate. Next, the polymer was filtered off using a suction filter, and the powder was further washed with heptane. After that, it was dried in a dryer at 60°C for 24 hours to obtain cyclic olefin resin (A-4). The weight-average molecular weight (Mw) of cyclic olefin resin (A-4) measured by GPC was 11,500, and the refractive index of cyclic olefin resin (A-4) measured by Abbe refractometer at 23°C and 589 nm was 1.51. The cyclic olefin resin (A-4) is a resin containing the structural unit represented by formula (a-1) and the structural unit represented by formula (b-1).

[0131] (Synthesis of cyclic olefin resin (A-5)) In a reaction vessel of appropriate size equipped with a stirrer and condenser, 900 g (5.0 mol) of methylglycidyl ether norbornene, 242.7 g (2.5 mol) of maleimide, 448.1 g (2.5 mol) of N-cyclohexyl maleimide, and 23.0 g (0.1 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed and dissolved in 2636 g of methyl ethyl ketone and 1130 g of toluene. After removing dissolved oxygen from the system by nitrogen bubbling, the vessel was sealed and reacted at 70°C for 16 hours. After the resulting solution was cooled to room temperature, it was reprecipitation in a large amount of heptane to obtain a polymer precipitate. Subsequently, the polymer was filtered off using a suction filter, and the powder was further washed with heptane. The mixture was then dried in a dryer at 60°C for 24 hours to obtain cyclic olefin resin (A-5). The weight-average molecular weight (Mw) of cyclic olefin resin (A-5) measured by GPC was 8,500, and the refractive index of cyclic olefin resin (A-5) measured by Abbe refractometer at 23°C and 589 nm was 1.51. The cyclic olefin resin (A-5) is a resin containing the structural unit represented by formula (a-1) and the structural unit represented by formula (b-1).

[0132] (Synthesis of cyclic olefin resin (A-6)) <For comparative example> First, the reaction vessel, equipped with a stirrer and condenser, was thoroughly purged with nitrogen. Then, 164 g (0.7 mol) of decyl norbornene, 54.1 g (0.3 mol) of methyl glycidyl ether norbornene, and 800 g of toluene were charged, and the mixture was heated to 50°C in an oil bath while stirring. To this, 5 g of a toluene solution of 26.9 g (0.014 mol) of (toluene)Ni(C6F5) was added, and the reaction was continued at 50°C for 3 hours. The resulting solution was reprecipitation in a large amount of methanol to obtain a polymer precipitate, which was then filtered using a suction filter to obtain a polymer powder. The obtained polymer was vacuum dried at 60°C for 16 hours to obtain cyclic olefin resin (A-6). The weight-average molecular weight (Mw) of cyclic olefin resin (A-6) measured by GPC was 100,000, and the refractive index of cyclic olefin resin (A-6) measured by Abbe refractometer at 23°C and 589 nm was 1.50. Cyclic olefin resin (A-6) is a resin that contains structural unit (a) but does not contain structural unit (b).

[0133] (Synthesis of cyclic olefin resin (A-8)) In a reaction vessel of appropriate size equipped with a stirrer and condenser, 540 g (3.0 mol) of methyl glycidyl ether norbornene, 1855 g (7.0 mol) of N-dodecyl maleimide, and 23.0 g (0.1 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed and dissolved in 3949 g of methyl ethyl ketone and 1693 g of toluene. After removing dissolved oxygen from the system by nitrogen bubbling, the vessel was sealed and reacted at 70°C for 16 hours. After the resulting solution was cooled to room temperature, it was reprecipitation in a large amount of heptane to obtain a polymer precipitate. Subsequently, the polymer was filtered off using a suction filter, and the powder was further washed with heptane. The mixture was then dried in a dryer at 60°C for 24 hours to obtain cyclic olefin resin (A-8). The weight-average molecular weight (Mw) of cyclic olefin resin (A-8) measured by GPC was 12,000, and the refractive index of cyclic olefin resin (A-8) measured by Abbe refractometer at 23°C and 589 nm was 1.52. The cyclic olefin resin (A-8) is a resin containing the structural unit represented by formula (a-1) and the structural unit represented by formula (b-1).

[0134] The details of the raw materials for each component in Table 1 are as follows:

[0135] <Resin (A)> (A-1) Cyclic olefin resin synthesized above (A-2) Cyclic olefin resin synthesized above (A-3) Cyclic olefin resin synthesized above (A-4) Cyclic olefin resin synthesized as described above (A-5) Cyclic olefin resin synthesized above (A-6) Cyclic olefin resin synthesized as described above (for comparative example) (A-7) JER-1256 (manufactured by Mitsubishi Chemical Corporation, aromatic phenoxy resin) (for comparative example) (A-8) Cyclic olefin resin synthesized above

[0136] [ka]

[0137] <Compound having a cyclic ether structure (B)> (B-1) Celoxide 2021P (manufactured by Daicel Corporation, epoxy compound with alicyclic structure, liquid at 23°C, refractive index 1.51) (B-2) EHPE-3150 (manufactured by Daicel Corporation, epoxy compound with alicyclic structure, solid at 23°C, refractive index 1.51) (B-3) Epicote YX-8000 (manufactured by Mitsubishi Chemical Corporation, epoxy compound with alicyclic structure, liquid at 23°C, refractive index 1.51) (B-4) Denacol EX-321L (manufactured by Nagase ChemteX Corporation, aliphatic epoxy compound, liquid at 23°C, refractive index 1.50) (B-5)OXT-221 (manufactured by Toagosei Co., Ltd., oxetane compound, liquid at 23°C, refractive index 1.50)

[0138] [ka]

[0139] <Hardening agent (C)> (C-1) CPI-310B (manufactured by Sunapro Co., Ltd., photocationic polymerization initiator) (C-2) San-Aid SI-B5 (manufactured by Sanshin Chemical Industry Co., Ltd., thermal cationic polymerization initiator) (C-3) Cureazole C11z (manufactured by Shikoku Chemicals Co., Ltd., an imidazole compound)

[0140] <Surfactant (D)> (D-1) BYK-333 (manufactured by Big Chemie Japan Co., Ltd., silicone-based surfactant)

[0141] <Organic solvent (E)> (E-1)2-butanone (E-2) Propylene glycol monomethyl ether acetate (E-3) Propylene glycol monomethyl ether

[0142] [Examples 1-10, 21 and Comparative Examples 1-3] (Preparation of resin compositions) Each raw material, formulated according to Table 1, was stirred at room temperature until the raw materials were completely dissolved to obtain a solution. The solution was then filtered through a PTFE filter with a pore size of 0.2 μm to obtain the varnish-like resin compositions of Examples 1-10, 21, and Comparative Examples 1-3, respectively.

[0143] (Film production) The resin compositions of Examples 1-10, 21 and Comparative Examples 1-3, obtained in the preparation of the above resin compositions, were applied to a 38 μm thick antistatic treated polyethylene terephthalate substrate using an applicator, with varnish applied so that the thickness after drying was the thickness of the resin layer shown in Table 1. After drying at 100°C for 10 minutes, an OPP cover film was attached to the surface of the resin layer formed by the resin composition to produce a film, thereby obtaining the films of Examples 1-10, 21 and Comparative Examples 1-3, respectively.

[0144] [Examples 11-20, 22 and Comparative Examples 4, 5] (Synthesis of polymers for core layer formation) In a glove box filled with dry nitrogen, where both moisture and oxygen concentrations were controlled to 1 ppm or less, 7.2 g (40.1 mmol) of hexylnorbornene (HxNB) and 12.9 g (40.1 mmol) of diphenylmethylnorbornenemethoxysilane were weighed into a 500 mL vial. 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the vial was sealed tightly with a silicone sealer. Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of anhydrous toluene were weighed into a 100 mL vial, a stirrer tip was added, and the vial was sealed tightly. The Ni catalyst was thoroughly stirred to completely dissolve it, obtaining the Ni catalyst solution. 1 mL of the Ni catalyst solution was accurately weighed using a syringe and quantitatively injected into the vial containing the two types of norbornene dissolved above. The vial was stirred at room temperature for 1 hour, and a significant increase in viscosity was observed. At this point, the stopper was removed, 60 g of tetrahydrofuran (THF) was added, and the mixture was stirred to obtain the reaction solution. A peracetic acid aqueous solution was prepared by adding 9.5 g of acetic anhydride, 18 g of hydrogen peroxide solution (30% concentration), and 30 g of deionized water to a 100 mL beaker and stirring. Next, the entire peracetic acid aqueous solution was added to the above reaction solution and stirred for 12 hours to perform the reduction treatment of Ni. Next, the completed reaction solution was transferred to a separatory funnel, the aqueous layer at the bottom was removed, and then 100 mL of a 30% aqueous solution of isopropyl alcohol was added and the mixture was vigorously stirred. After standing, complete two-layer separation occurred, and the aqueous layer was removed. This washing process was repeated a total of three times. The oil layer was then dropped dropwise into a large excess of acetone to reprecipitate the resulting polymer, which was separated from the filtrate by filtration. Finally, the polymer for forming the core layer was obtained by heating and drying in a vacuum dryer set to 60°C for 12 hours.

[0145] The molecular weight of the core layer-forming polymer was determined to be Mw = 100,000 and Mn = 40,000, as determined by GPC measurement. Furthermore, the molar ratio of each structural unit in the core layer-forming polymer was determined to be 50 mol% for hexylnorbornene structural units and 50 mol% for diphenylmethylnorbornenemethoxysilane structural units, as determined by NMR measurement.

[0146] (Preparation of resin composition for core layer formation) Ten g of the purified polymer for core layer formation was weighed into a 100 mL glass container. To this, 30 g of methylcyclohexane, 2.4 g of oxetane compound (manufactured by Toagosei Co., Ltd., product name: OXT-213), 0.8 g of epoxy compound (manufactured by Daicel Corporation, product name: Celoxide 2021P), 0.03 g of photocationic polymerization initiator (manufactured by Sunapro Co., Ltd., product name: CPI-310B), and 0.1 g of antioxidant (manufactured by BSF, product name: Irganox 1076) were added and dissolved uniformly. The mixture was then filtered through a 0.2 μm PTFE filter to obtain a resin composition for core layer formation.

[0147] (Preparation of dry film for core layer formation) The obtained core layer forming resin composition was coated onto a release-treated PET film using an applicator to achieve a dry film thickness of 40 μm. After coating, the film was placed in a 45°C dryer for 5 minutes to completely remove the solvent and form a coating, thereby obtaining a dry film for core layer formation.

[0148] (Core layer fabrication) On the resulting dry film for core layer formation, an exposure dose of 100 mJ / cm² was applied using a direct-writing exposure machine (SCREEN Corporation, product name: LI-9000). 2 By irradiating with ultraviolet light, 20 line-and-space lines were created, each 9 cm long with an exposed area of ​​10 μm and an unexposed area of ​​50 μm. Subsequently, the samples were placed in a 160°C oven for 1 hour to obtain a core layer. A clear waveguide pattern (multiple core sections) with a rectangular cross-section was observed in the obtained core layer.

[0149] (Fabrication of photoelectric composite substrates) In the fabrication of the optoelectronic composite substrate, the film of the first cladding layer and the film of the second cladding layer refer to the cladding films listed in Table 2, respectively. The cladding types listed in Table 2 refer to the cladding types listed in Table 1. For example, "Cladding A" refers to the film obtained in Example 1. First, a 24cm x 16cm double-sided copper-clad laminate was placed on a stainless steel plate. The OPP cover film of the first cladding layer was peeled off, and the double-sided copper-clad laminate and the first cladding layer were laminated using a vacuum laminator (Nikko Materials Co., Ltd., product name: CVP-300) under the conditions of temperature: 140℃, pressure: 0.5MPa, and time: 120 seconds, so that they were in contact, to obtain a laminate. After peeling off the PET film derived from the first cladding layer, an exposure machine (SCREEN Co., Ltd., product name: LI-9000) was used to expose the laminate at an exposure dose of 1000mJ / cm². 2 The entire surface was irradiated with ultraviolet light, and then heated in a 120°C oven for 1 hour to obtain a laminate 1 having a layer structure of "double-sided copper-clad laminate / first cladding layer".

[0150] After the process described above (creation of the core layer) was performed, the core layer in the dry film for core layer formation was subjected to oxygen plasma treatment. Then, the first cladding layer in the laminate 1 and the core layer were laminated using a vacuum laminator under the same conditions as the lamination process of the laminate 1, so that the core layer was in contact with the first cladding layer in the laminate 1. The PET film derived from the dry film for core layer formation was peeled off to obtain a laminate 2 with a layer structure of "double-sided copper-clad laminate / first cladding layer / core layer".

[0151] Next, the core layer of laminate 2 was subjected to oxygen plasma treatment, and then the cover film of the second cladding layer was peeled off. The core layer and the second cladding layer in laminate 2 were then laminated using a vacuum laminator under the same conditions as the lamination of laminate 1, so that they were in contact. The PET film derived from the second cladding layer was peeled off to obtain laminate 3, which has a layer structure of "double-sided copper-clad laminate / first cladding layer / core layer / second cladding layer".

[0152] Next, the second cladding layer in the laminate 3 and the polyimide substrate (manufactured by UBE Corporation, product name: UPILEX 25S, thickness 25 μm) were laminated using a vacuum laminator under the same conditions as the lamination process for laminate 1, so that they were in contact, to obtain laminate 4 with a layer structure of "double-sided copper-clad laminate / first cladding layer / core layer / second cladding layer / polyimide substrate".

[0153] The resulting laminate 4 was heat-treated in an oven at 180°C for 1 hour to obtain the optoelectronic composite substrates for Examples 11-20, 22 and Comparative Examples 4 and 5, respectively.

[0154] [evaluation] The evaluation methods for the examples and comparative examples are described below.

[0155] <Evaluation of coating properties> The appearance of the films from Examples 1-10, 21 and Comparative Examples 1-3 was observed. Samples without appearance abnormalities like those in Standard B were evaluated as A, and samples exhibiting appearance abnormalities (uneven coating, clouding, repelling, cracks, etc.) were evaluated as B.

[0156] <Evaluation of refractive index> For the films of Examples 1-10, 21 and Comparative Examples 1-3, the OPP cover film was peeled off, and the refractive index was measured at 23°C and 589 nm using an Abbe refractometer (manufactured by Atago Co., Ltd., product name: NAR-1T SOLID). A lower refractive index is preferable from the standpoint of maximizing the refractive index difference with the core layer.

[0157] <Measurement of light transmittance at a wavelength of 850 nm> For the films of Examples 1-10, 21 and Comparative Examples 1-3, the OPP cover film was peeled off, and the films were laminated onto a slide glass with the resin layer formed by the resin composition facing the slide glass side under the conditions of temperature: 100°C, pressure: 0.5 MPa, and time: 2 minutes. After that, the base film was peeled off to obtain a sample for transmittance measurement (slide glass with resin composition). Subsequently, a 100% correction was performed using a UV-Vis spectrophotometer (JASCO Corporation, product name: V-670) with slide glass placed in both the background slot and the sample slot. The slide glass on the measurement slot side was then replaced with the transmittance measurement sample, and the light transmittance [%] at a wavelength of 850 nm was measured in transmittance measurement mode.

[0158] <Evaluation of implantability> A 50 μm thick double-sided copper-clad laminate (CCL) with 100 μmΦ via holes was prepared. The OPP cover film of the films from Examples 1-10, 21 and Comparative Examples 1-3 was peeled off, and the films were attached to the CCL so that the resin layer formed by the resin composition was facing the CCL side. Lamination was then performed using a laminator at a temperature of 100°C, a pressure of 5.0 MPa, and a time of 2 minutes. The via holes of the obtained substrates were observed under a microscope and evaluated as follows: samples with no voids and complete filling were classified as A, samples with insufficient filling as B, and samples with filling defects such as bleeding after filling as C.

[0159] <Evaluation of optical loss> For the photoelectric composite substrates in Examples 11-20, 22 and Comparative Examples 4 and 5, both sides were diced so that the pattern length was 7 cm, and samples for optical loss evaluation were obtained. For the samples used to evaluate optical loss, propagation loss was evaluated in accordance with the cutback method described in section 4.6.2.1 of the "Test Method for Polymer Optical Waveguides (JPCA-PE02-05-01S-2008)". Light with a wavelength of 850 nm was used for the measurements. Based on the results, samples with propagation loss of less than 1 dB were classified as A, samples with propagation loss between 1 dB and 3 dB were classified as B, and samples with propagation loss exceeding 3 dB were classified as C.

[0160] The evaluation results for each example and each comparative example are shown in Tables 1 and 2, respectively.

[0161] [Table 1]

[0162] [Table 2]

[0163] As shown in Table 1, all of the films in the examples showed good results in the embeddability evaluation. Furthermore, the films in the examples did not experience a decrease in light transmittance at a wavelength of 850 nm, unlike the film in Comparative Example 2. In other words, it can be seen that the resin composition of this embodiment can improve embeddability while suppressing a decrease in light transmittance.

[0164] Table 2 shows that all of the photoelectric composite substrates in the embodiment performed well in the optical loss evaluation. In other words, it can be seen that propagation loss can be suppressed with the photoelectric composite substrate of this embodiment.

[0165] This application claims priority based on Japanese Patent Application No. 2023-166734, filed on 28 September 2023, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0166] 20. First cladding layer 30 core layers 40. Second cladding layer 50 Mirror on the light-emitting element side 60 Mirror on the light-receiving element side 100 optical waveguide 110 circuit boards 120 light-emitting elements 130 Photodetector 140a, 140b via 200 Optoelectronic composite substrate

Claims

1. A resin composition used in optical waveguide cladding, Contains a cyclic olefin resin (A), The cyclic olefin resin (A) comprises structural unit (a) and structural unit (b), The aforementioned structural unit (a) is a structural unit represented by the following formula (a-1), The aforementioned structural unit (b) is one or more selected from the group consisting of the structural unit represented by the following formula (b-1), the structural unit represented by the following formula (b-2), and the structural unit represented by the following formula (b-3). The compound further comprises a compound (B) having a cyclic ether structure, For a resin film made of the resin composition with a thickness of 25 μm, the light transmittance of the resin composition at a wavelength of 850 nm, as measured by an ultraviolet-visible spectrophotometer, is 85% or more. The content of the structural unit (a) in the cyclic olefin resin (A) is 10 mol% or more and 70 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%, The content of the structural unit (b) in the cyclic olefin resin (A) is 10 mol% or more and 70 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%, The content of the cyclic olefin resin (A) in the resin composition is 20 parts by mass or more, when the total content of resin components in the resin composition is 100 parts by mass. A resin composition having a refractive index of 1.47 or more and 1.55 or less, as measured using an Abbe refractometer under conditions of 23°C and 589 nm. 【Chemistry 1】 (In formula (a-1), R １ , R ２ , R ３ and R ４ Each of these independently represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms. 【Chemistry 2】 (In formula (b-1), R １１ (This represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms.) 【Transformation 3】 【Chemistry 4】 (In formula (b-3), R ２１ and R ２２ Each of these independently represents a hydrogen atom or an organic group with 1 to 30 carbon atoms.

2. A resin composition used in optical waveguide cladding, Contains a cyclic olefin resin (A), The cyclic olefin resin (A) comprises structural unit (a) and structural unit (b), The aforementioned structural unit (a) is a structural unit represented by the following formula (a-1), The aforementioned structural unit (b) is one or more selected from the group consisting of the structural unit represented by the following formula (b-1), the structural unit represented by the following formula (b-2), and the structural unit represented by the following formula (b-3). Further containing a hardening agent (C), The curing agent (C) comprises a cationic polymerization initiator. For a resin film made of the resin composition with a thickness of 25 μm, the light transmittance of the resin composition at a wavelength of 850 nm, as measured by an ultraviolet-visible spectrophotometer, is 85% or more. The content of the structural unit (a) in the cyclic olefin resin (A) is 10 mol% or more and 70 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%, The content of the structural unit (b) in the cyclic olefin resin (A) is 10 mol% or more and 70 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%, The content of the cyclic olefin resin (A) in the resin composition is 20 parts by mass or more, when the total content of resin components in the resin composition is 100 parts by mass. A resin composition having a refractive index of 1.47 or more and 1.55 or less, as measured using an Abbe refractometer under conditions of 23°C and 589 nm. 【Transformation 5】 (In formula (a-1), R １ , R ２ , R ３ and R ４ each independently represent a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms.) 【Transformation 6】 (In formula (b-1), R １１ (This represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms.) 【Transformation 7】 【Transformation 8】 (In formula (b-3), R ２１ and R ２２ Each of these independently represents a hydrogen atom or an organic group with 1 to 30 carbon atoms.

3. A resin composition used in optical waveguide cladding, Contains a cyclic olefin resin (A), The cyclic olefin resin (A) comprises structural unit (a) and structural unit (b), The aforementioned structural unit (a) is a structural unit represented by the following formula (a-1), The aforementioned structural unit (b) is one or more selected from the group consisting of the structural unit represented by the following formula (b-1), the structural unit represented by the following formula (b-2), and the structural unit represented by the following formula (b-3). Further containing a hardening agent (C), The curing agent (C) comprises an imidazole compound, For a resin film made of the resin composition with a thickness of 25 μm, the light transmittance of the resin composition at a wavelength of 850 nm, as measured by an ultraviolet-visible spectrophotometer, is 85% or more. The content of the structural unit (a) in the cyclic olefin resin (A) is 10 mol% or more and 70 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%, The content of the structural unit (b) in the cyclic olefin resin (A) is 10 mol% or more and 70 mol% or less, when the total amount of all structural units in the cyclic olefin resin (A) is taken as 100 mol%, The content of the cyclic olefin resin (A) in the resin composition is 20 parts by mass or more, when the total content of resin components in the resin composition is 100 parts by mass. A resin composition having a refractive index of 1.47 or more and 1.55 or less, as measured using an Abbe refractometer under conditions of 23°C and 589 nm. 【Chemistry 9】 (In formula (a-1), R １ , R ２ , R ３ and R ４ Each of these independently represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms. 【Chemistry 10】 (In formula (b-1), R １１ (This represents a hydrogen atom, a hydroxyl group, or an organic group with 1 to 30 carbon atoms.) 【Chemistry 11】 【Chemistry 12】 (In formula (b-3), R ２１ and R ２２ Each of these independently represents a hydrogen atom or an organic group with 1 to 30 carbon atoms.

4. The resin composition according to any one of claims 1 to 3, wherein the refractive index of the cyclic olefin resin (A) is 1.45 or more and 1.55 or less.

5. The resin composition according to any one of claims 1 to 3, wherein the content of the cyclic olefin resin (A) in the resin composition is 80 parts by mass or less when the total content of resin components in the resin composition is 100 parts by mass.

6. The resin composition according to claim 2 or 3, further comprising a compound (B) having a cyclic ether structure.

7. The compound (B) has a cyclic ether structure, The resin composition according to any one of claims 1 to 3, wherein the compound (B) having the cyclic ether structure comprises at least one or more selected from the group consisting of epoxy compounds and oxetane compounds.

8. The compound (B) has a cyclic ether structure, The resin composition according to any one of claims 1 to 3, wherein the compound (B) having the cyclic ether structure contains an alicyclic structure within the molecule.

9. The compound (B) has a cyclic ether structure, The resin composition according to any one of claims 1 to 3, wherein the compound (B) having the cyclic ether structure contains two or more cyclic ether structures within the molecule.

10. The compound (B) has a cyclic ether structure, The resin composition according to any one of claims 1 to 3, wherein the compound (B) having the cyclic ether structure is liquid at 23°C.

11. The compound (B) has a cyclic ether structure, The resin composition according to any one of claims 1 to 3, wherein the refractive index of the compound (B) having the cyclic ether structure is 1.45 or more and 1.55 or less.

12. The compound (B) has a cyclic ether structure, The resin composition according to any one of claims 1 to 3, wherein the content of the compound (B) having the cyclic ether structure in the resin composition is 20 parts by mass or more and 80 parts by mass or less, when the total content of resin components in the resin composition is 100 parts by mass.

13. The resin composition according to claim 1, further comprising a curing agent (C).

14. Contains a hardening agent (C), The resin composition according to claim 1 or 3, wherein the curing agent (C) comprises a cationic polymerization initiator.

15. Contains a hardening agent (C), The curing agent (C) comprises a cationic polymerization initiator. The resin composition according to any one of claims 1 to 3, wherein the cationic polymerization initiator comprises a photocationic polymerization initiator.

16. Contains a hardening agent (C), The curing agent (C) comprises a cationic polymerization initiator. The resin composition according to any one of claims 1 to 3, wherein the cationic polymerization initiator comprises a thermal cationic polymerization initiator.

17. Contains a hardening agent (C), The resin composition according to claim 1 or 2, wherein the curing agent (C) comprises an imidazole compound.

18. Contains a hardening agent (C), The resin composition according to any one of claims 1 to 3, wherein the content of the curing agent (C) contained in the resin composition is 0.05 parts by mass or more and 10.0 parts by mass or less, when the total content of resin components in the resin composition is 100 parts by mass.

19. A resin film comprising the resin composition according to any one of claims 1 to 3, The resin film is a resin film having a light transmittance of 85% or more for a wavelength of 850 nm.

20. The resin film according to claim 19, wherein the resin film has a thickness of 1 μm or more and 150 μm or less.

21. A film that can be used in optical waveguide cladding, A film comprising a resin layer formed by the resin composition according to any one of claims 1 to 3.

22. Furthermore, it includes a base film, The film according to claim 21, having the resin layer on the base film.

23. The film according to claim 22, wherein the resin constituting the base film comprises at least one or more selected from the group consisting of polyimide and polyethylene terephthalate.

24. The film according to claim 21, wherein the film is a dry film.

25. A film set that can be used in optical waveguide cladding, Including a first film and a second film, A film set in which at least one of the first film and the second film is the film described in claim 21.

26. An optical waveguide in which a first cladding layer, a core layer, and a second cladding layer are stacked in this order, An optical waveguide in which at least one of the first cladding layer and the second cladding layer comprises the resin composition according to any one of claims 1 to 3.

27. circuit board and An optoelectronic composite substrate comprising an optical waveguide according to claim 26 provided on the substrate.

28. An electronic component comprising the photoelectric composite substrate described in claim 27.

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