Resin composition, resin film, film, film set, optical waveguide, opto-electric composite substrate, and electronic component

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 technology]

[0002] BACKGROUND ART In recent years, there has been a demand for components in information and communication devices that can realize more advanced information communication, such as larger information capacity and faster information communication speed, and an optoelectronic composite substrate has been considered as one such component.

[0003] An example of an optical / electrical composite substrate is one in which an optical waveguide is provided on a substrate. Examples of techniques relating to optical and electrical composite substrates include those described in Patent Documents 1 and 2.

[0004] Patent document 1 describes an opto-electrical hybrid board comprising a flexible circuit board having electrical wiring with mounting pads formed on the surface of an insulating layer, an element mounted on the mounting pad, and an optical waveguide laminated on the back side of the insulating layer, wherein the flexible circuit board is a flexible double-sided circuit board having electrical wiring also formed on the back side of the insulating layer, and a metal reinforcing layer is plated on at least the portion of the electrical wiring on the back side that corresponds to the mounting pad, and the optical waveguide is in contact with the metal reinforcing layer. According to the opto-electrical hybrid board described in Patent Document 1, a metal reinforcing layer is adhered to the insulating layer of a flexible circuit board without an adhesive layer, and it is described that an opto-electrical hybrid board can be provided in which the metal reinforcing layer prevents deformation due to a pressure load when the element is mounted and the element is properly mounted.

[0005] Patent Document 1 describes that a substrate is prepared in which copper foil 21 is formed on the front and back surfaces of an insulating layer 1 made of a resin such as polyimide, and that through holes 1a and via holes 1b for optical paths are formed in the substrate (see paragraph 0023 of Patent Document 1). It also describes a flexible double-sided circuit board E in which a metal reinforcing layer M is formed (see paragraph 0028 of Patent Document 1). The flexible double-sided circuit board E includes the above-mentioned substrate. Furthermore, Patent Document 1 describes that an undercladding layer 6 is formed on the back side of a flexible double-sided circuit board E in contact with a metal reinforcing layer M that covers the electrical wiring 2B on the back side, and describes that examples of molding materials for the undercladding layer 6 include photosensitive resins and thermosetting resins (see paragraph 0029 of Patent Document 1).From Figures 4 to 6 of Patent Document 1, it can be seen that the molding material for the undercladding layer 6 is filled into 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 opto-electrical wiring board that is formed by integrating a rigid section in which conductor circuits and insulating layers are laminated on both sides of a substrate with one or more bendable flex sections, wherein the rigid section has external connection terminals formed therein for mounting optical elements and / or package substrates on which optical elements are mounted, and at least one of the flex sections has optical wiring formed therein. According to the optoelectronic wiring board of Patent Document 2, it is described that large amounts of information can be suitably processed and information can be processed at high speed without increasing the size of the wiring board.

[0007] Patent Document 2 describes that the rigid section has an optical signal transmitting region formed therein, and that the optical signal transmitting region is filled with a resin composition (see claims 4 and 5 of Patent Document 2). Furthermore, Patent Document 2 describes that the optical signal transmitting region is formed so as to penetrate all of the substrates and insulating layers that make up the rigid section (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 states that the resin layer 221a forms part of the optical signal transmitting regions 242a, 242b (see paragraph 0033 of Patent Document 2). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-238455 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-140233 Summary of the Invention [Problem to be solved by the invention]

[0010] As described in Patent Documents 1 and 2, in conventional technologies relating to optical and electrical composite substrates, there is known an optical and electrical composite substrate in which recesses and vias formed in a substrate are filled with a resin composition.

[0011] One example of a manufacturing process for an optoelectronic composite substrate is a process of integrating a substrate having vias formed therein with a film for optical waveguide cladding. In this process, the vias formed in the substrate must be embedded with the optical waveguide cladding. That is, a resin composition that can be used for the optical waveguide cladding is required to have properties that enable the resin composition to be sufficiently embedded in the vias (hereinafter, "embeddability" refers to the property of the degree to which the resin composition that can be used for the optical waveguide cladding can be embedded in the vias).

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

[0013] The present invention has been 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] According to the present invention, there are provided 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 for an optical waveguide clad, 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 the following formula (a-1): The structural unit (b) is one or more selected from the group consisting of a structural unit represented by the following formula (b-1), a structural unit represented by the following formula (b-2), and a structural unit represented by the following formula (b-3). [ka] (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. [ka] (In formula (b-1), R 11 represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms. [ka] [ka] (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. [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 of all structural units in the cyclic olefin resin (A) is 100 mol %. [3] The resin composition according to [1] or [2] above, 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 the resin components in the resin composition is 100 parts by mass. [5] The resin composition according to any one of the above [1] to [4], further comprising a compound (B) having a cyclic ether structure. [6] The resin composition according to [5] above, wherein the compound (B) having a cyclic ether structure includes at least one or more compounds selected from the group consisting of epoxy compounds and oxetane compounds. [7] The resin composition according to [5] or [6] above, wherein the compound (B) having a cyclic ether structure contains an alicyclic structure in the molecule. [8] The resin composition according to any one of [5] to [7] above, wherein the compound (B) having a cyclic ether structure contains two or more cyclic ether structures in the molecule. [9] The resin composition according to any one of the above [5] to [8], wherein the compound (B) having a cyclic ether structure is liquid at 23°C.

[10] The resin composition according to any one of [5] to [9] above, wherein the refractive index of the compound (B) having a 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 a 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] The 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] above, wherein the curing agent (C) contains a cationic polymerization initiator.

[14] The resin composition according to

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

[15] The resin composition according to

[13] or

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

[16] The resin composition according to any one of the above

[12] to

[15] , wherein the curing agent (C) contains an imidazole-based 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] above, wherein the refractive index of the resin composition is 1.47 or more and 1.55 or less.

[19] A resin film made of the resin composition according to any one of [1] to

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

[20] The resin film according to

[19] above, wherein the resin film has a thickness of 1 μm or more and 150 μm or less. [twenty one] A film that can be used for an optical waveguide clad, A film comprising a resin layer formed from the resin composition according to any one of [1] to

[18] above. [twenty two] Further, a base film is provided, The film according to

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

[22] above, wherein the resin constituting the base film contains 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] above, wherein the film is a dry film. [twenty five] A film set that can be used for an optical waveguide clad, a first film and a second film, A film set, wherein at least one of the first film and the second film is the film according to any one of

[21] to

[24] above.

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

[18] above.

[27] A substrate; An optical / electrical composite substrate comprising: the optical waveguide according to

[26] provided on the substrate.

[28] An electronic component comprising the optical / electrical composite substrate according to

[27] . [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 drawings]

[0017] [Figure 1] 1 is a cross-sectional view schematically showing an example of the structure of an optoelectronic composite substrate according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are simplified and do not correspond to actual dimensional proportions. Numerical ranges "A to B" represent A or more and B or less unless otherwise specified.

[0019] FIG. 1 is a cross-sectional view showing a schematic example of the structure of an optoelectronic composite substrate according to this embodiment. As shown in FIG. 1, an optical / electrical composite substrate 200 has an optical waveguide 100 provided on a substrate 110. The optical waveguide 100 includes a first cladding layer 20, a core layer 30, and a second cladding layer 40 laminated in this order. A mirror 50 on the light-emitting element side and a mirror 60 on the light-receiving element side are formed in the optical waveguide 100. Vias 140 (140a, 140b) are formed in the substrate 110 (note that the via 140 shown in FIG. 1 is buried in 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 the optical waveguide 100 side.

[0020] The propagation path of light in the optical / electrical composite substrate 200 will be specifically described using Figure 1. Light emitted from the light-emitting portion of the light-emitting element 120 passes through via 140a formed in the substrate 110, enters mirror 50 on the light-emitting element side, and after being transmitted through the core layer 30, enters mirror 60 on the light-receiving element side, passes through via 140b formed in the substrate 110, and enters light-receiving element 130. The arrows in Figure 1 are a schematic representation of the propagation of light.

[0021] Providing the optical waveguide 100 on the substrate 110 includes, for example, a step of laminating the substrate 110, in which the via 140 is formed, and a film for forming the first cladding layer 20, and integrating them by heating and pressurizing. In the integration step, the via 140 needs to be embedded in the first cladding layer 20.

[0022] According to the inventors' investigations, it was found that with conventional materials for forming optical waveguide cladding, the optical waveguide cladding cannot be sufficiently embedded in the vias formed in the substrate, and that this can result in depressions on the surface of the optical waveguide cladding opposite the substrate side (i.e., the core layer side of the optical waveguide cladding) or voids in the vias.The inventors also found that when the above-mentioned depressions or voids occur in the optoelectronic composite substrate, optical loss occurs at the interfaces of the depressions or voids. In other words, a resin composition that can be used for the cladding of an optical waveguide is required to have properties that enable the resin composition to be sufficiently embedded in vias.

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

[0024] The present invention has been 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 optical / electrical composite substrate capable of suppressing propagation loss.

[0026] [Resin composition] The resin composition of this embodiment is a resin composition that can be used for an optical waveguide clad, 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), and the structural unit (b) is one or more structural units 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).

[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] [ka]

[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] [ka]

[0032] [ka]

[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 this embodiment is preferably 1.55 or less, more preferably 1.54 or less, even more preferably 1.53 or less, and even more preferably 1.52 or less. The lower limit is not particularly limited, but may be, for example, 1.47 or more, or 1.48 or more. The refractive index of the resin composition means the refractive index measured for a resin film made of the resin composition using an Abbe refractometer under conditions of 23° C. and 589 nm. A resin film made of the resin composition can be produced, for example, by applying the resin composition onto a substrate film and drying it, as in the method described in the Examples.

[0035] The light transmittance of the resin composition of this embodiment at a wavelength of 850 nm is preferably 85% or more, more preferably 90% or more, even more preferably 95% or more, even more preferably 97% or more, and even more preferably 98% or more, from the viewpoint of further improving the light propagation efficiency of the optical waveguide. The light transmittance of the resin composition at a wavelength of 850 nm means the light transmittance value measured by a UV-visible spectrophotometer for a resin film made of the resin composition and having a thickness of 25 μm. A resin film made of a resin composition having a thickness of 25 μm can be produced, for example, by applying the resin composition onto a substrate film and drying it, as in the method described in the Examples.

[0036] The shape of the resin composition of the present embodiment is not particularly limited, and examples thereof include a film, membrane, varnish, and sheet.

[0037] Hereinafter, each of the constituent components of the resin composition of this embodiment will be described.

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

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

[0040] [ka]

[0041] 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. 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 the organic group constituting the formula (I) include at least one selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkylidene group, an aryl group, an aralkyl group, an alkaryl group, a cycloalkyl group, an organic group having a carboxyl group, and an organic group having a heterocycle. Examples of the alkyl group include at least one selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and a dodecyl group. The alkenyl group may be, for example, at least one selected from the group consisting of an allyl group, a pentenyl group, a vinyl group, and the like. Examples of the alkynyl group include an ethynyl group. The alkylidene group may be, for example, at least one selected from the group consisting of a methylidene group, an ethylidene group, and the like. The aryl group may be, for example, at least one selected from the group consisting of a phenyl group, a naphthyl group, an anthracenyl group, and the like. The aralkyl group may be, for example, at least one selected from the group consisting of a benzyl group, a phenethyl group, and the like. The alkaryl group may be, for example, at least one selected from the group consisting of a tolyl group, a xylyl group, and the like. The cycloalkyl group may be, for example, at least one selected from the group consisting of an adamantyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and the like. Examples of organic groups having a heterocycle include organic groups having an epoxy group and an oxetanyl group.

[0043] R 1 , R 2 , R 3 and R 4 In the organic groups constituting the above, one or more hydrogen atoms in the alkyl group, alkenyl group, alkynyl group, alkylidene group, aryl group, aralkyl group, alkaryl group, cycloalkyl group, organic group having a carboxyl group, and organic group having a heterocycle may be substituted with a halogen atom. Examples of the halogen atom 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 At least one selected from the group consisting of is preferably an alkyl group. In addition, from the viewpoint of further improving the heat resistance and strength of the cured product of the resin composition, R 1 , R 2 , R 3 and R 4 At least one selected from the group consisting of: is preferably at least one selected from the group consisting of an organic group having a carboxyl group and an organic group having a heterocycle.

[0045] Among these, in formula (a-1), R 1 , R 2 , R 3 and R 4preferably each independently represent a hydrogen atom, an organic group having a carboxyl group, or an organic group having a heterocycle, more preferably a hydrogen atom, an organic group having a carboxyl group, or an organic group having an epoxy group, even more preferably a hydrogen atom, an organic group having 1 to 8 carbon atoms and having a carboxyl group, or an organic group having 1 to 8 carbon atoms and having an epoxy group, and even more preferably a hydrogen atom, an organic group having 1 to 4 carbon atoms and having a carboxyl group, or an organic group having 1 to 4 carbon atoms and having an epoxy group.

[0046] In the cyclic olefin resin (A), 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).

[0047] The structural unit represented by formula (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 having 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 The organic group constituting the formula (I) may be, for example, at least one selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, and cycloalkyl groups. R 11 Specific examples of the alkyl group, alkenyl group, alkynyl group, alkylidene group, aryl group, aralkyl group, alkaryl group and cycloalkyl group as the organic group constituting R 1, R 2 , R 3 and R 4 The specific examples are the same as those described for the organic groups constituting the above.

[0051] R 11 In the organic group constituting the formula (I), one or more hydrogen atoms may be substituted with halogen atoms, such as fluorine, chlorine, bromine, and iodine.

[0052] Among these, in formula (b-1), R 11 preferably represents a hydrogen atom, an alkyl group or a cycloalkyl group, and R 11 more preferably 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 preferably represents a hydrogen atom, a dodecyl group or a cyclohexyl group.

[0053] The structural unit represented by formula (b-2) is shown below.

[0054] [ka]

[0055] The structural unit represented by formula (b-3) is shown below.

[0056] [ka]

[0057] 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. 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 the organic group constituting the formula (I) include at least one selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an alkylidene group, an aryl group, an aralkyl group, an alkaryl group, a cycloalkyl group, a group having an acryloyl group, and a group having a methacryloyl group. R 21 and R 22 Specific examples of the alkyl group, alkenyl group, alkynyl group, alkylidene group, aryl group, aralkyl group, alkaryl group and cycloalkyl group as the organic group constituting R 1 , R 2 , R 3 and R 4 The specific examples are the same as those described for the organic groups constituting the above.

[0059] R 21 and R 22 In the organic group constituting the formula (I), one or more hydrogen atoms may be substituted with halogen atoms, such as fluorine, chlorine, bromine, and iodine.

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

[0061] Formula (b-3) is R 21 is a hydrogen atom, and R 22 is preferably an organic group having 1 to 30 carbon atoms, and R 21 is a hydrogen atom, and R 22 is more preferably an alkyl group, and R 21 is a hydrogen atom, and R 22 is more preferably an alkyl group having 1 to 10 carbon atoms, and R 21 is a hydrogen atom, and R 22 More preferably, is an n-butyl group.

[0062] The cyclic olefin resin (A) may contain a structural unit other than the structural unit (a) and the structural unit (b). Examples of other structural units include structural units derived from compounds having an ethylenic double bond. Examples of compounds having an ethylenic double bond include α-olefins having 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-methyl-1-hexene, 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; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, and 1,7-octadiene; 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 ethyloxetane vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, and allyl vinyl ether.

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

[0064] The content of the structural unit (b) in the cyclic olefin resin (A), when the total of all structural units in the cyclic olefin resin (A) is 100 mol%, 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 is preferably 70 mol% or less, more preferably 65 mol% or less, even more preferably 60 mol% or less.

[0065] The total content of the structural unit (a) and the 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, when the total of all structural units in the cyclic olefin resin (A) is 100 mol%, and is, for example, 100 mol% or less.

[0066] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, 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. 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 the cyclic olefin resin (A) means the refractive index measured with an Abbe refractometer under the conditions of 23° C. and 589 nm.

[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 the solubility in organic solvents, 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 the cyclic olefin resin (A) can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0068] The content of cyclic olefin resin (A) in the resin composition of this embodiment, when the total content of the resin components of the resin composition is 100 parts by mass, 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 is 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, when the total content of all components of the resin composition is 100 mass%, is preferably 5 mass% or more, more preferably 8 mass% or more, even more preferably 10 mass% or more, even more preferably 20 mass% or more, even more preferably 25 mass% or more, and even more preferably 28 mass% or more, from the viewpoint of further improving embeddability while suppressing a decrease in light transmittance, and is preferably less than 100 mass%, more preferably 80 mass% or less, more preferably 75 mass% or less, even more preferably 70 mass% or less, and even more preferably 65 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 a known method, more specifically, by polymerizing monomers capable of forming each structural unit by any method. Examples of monomers capable of forming the structural unit represented by formula (a-1) include 2-norbornene, methyl glycidyl ether norbornene, and 5-norbornene-2-carboxylic acid. Examples of monomers capable of forming the structural unit represented by formula (b-1) include maleimide and N-cyclohexylmaleimide. An example of a monomer capable of forming the structural unit represented by formula (b-2) is maleic anhydride. Examples of monomers capable of forming the structural unit represented by formula (b-3) include 1-butyl hydrogen maleate and ethyl hydrogen maleate.

[0071] The cyclic olefin resin (A) may be a single cyclic olefin resin, or may contain two or more cyclic olefin resins.

[0072] <Compound (B) Having a Cyclic Ether Structure> From the viewpoint of further improving embeddability, the resin composition of the present 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. In addition, 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] The compound (B) having a cyclic ether structure preferably contains an alicyclic structure in the molecule. Here, the compound (B) having a cyclic ether structure containing an alicyclic structure in the molecule 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 bond atom. The number of ring members in the alicyclic structure is not particularly limited, but is preferably a 4- to 10-membered ring, more preferably a 4- to 8-membered ring, even more preferably a 5- or 6-membered ring, and even more preferably a 6-membered ring.

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

[0076] The compound (B) having a cyclic ether structure is preferably liquid at 23°C from the viewpoint of ease of handling when producing a resin composition.

[0077] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the refractive index of the 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. 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 the compound (B) having a cyclic ether structure means the refractive index measured with an Abbe refractometer under the conditions of 23° C. and 589 nm.

[0078] The content of the 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, and even more preferably 35 parts by mass or more, when the total content of the resin components in the resin composition is taken as 100 parts by mass, from the viewpoint of further improving embeddability, and is preferably 80 parts by mass or less, and more preferably 75 parts by mass or less.

[0079] The compound (B) having a cyclic ether structure may be a compound having one type of cyclic ether structure, or may contain compounds having two or more types of cyclic ether structures.

[0080] <Curing agent (C)> The resin composition of the present embodiment preferably further contains a curing agent (C). The curing agent (C) may be, for example, 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 the cationic polymerization initiator include a photo-cationic polymerization initiator and a thermal cationic polymerization initiator.

[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, etc., 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, an iodonium salt type polymerization initiator, etc., and preferably includes a sulfonium salt type polymerization initiator.

[0084] The curing agent (C) preferably contains an imidazole compound. The imidazole compound refers to a compound containing an imidazole ring structure, such as a compound in which the hydrogen of imidazole is substituted with a hydrocarbon group or the like.

[0085] The content of the 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 is preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, even more preferably 6.0 parts by mass or less, when the total content of the resin components in the resin composition is 100 parts by mass.

[0086] When the curing agent (C) contains at least one selected from the group consisting of a photocationic polymerization initiator and a thermal cationic polymerization initiator, the content of the curing agent (C) contained in the resin composition of the present embodiment is, when the total content of the resin components in the resin composition is taken as 100 parts by mass, 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, even more preferably 0.5 parts by mass or less.

[0087] When the curing agent (C) contains an imidazole-based compound, the content of the curing agent (C) contained in the resin composition of the present embodiment is, when the total content of the resin components in the resin composition is taken as 100 parts by mass, 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, even more preferably 6.0 parts by mass or less.

[0088] The curing agent (C) of the present embodiment may contain one type of curing agent, or may contain two or more types of curing agents.

[0089] <Surfactant (D)> From the viewpoint of further improving embeddability, the resin composition of the present embodiment preferably further contains a surfactant (D). The surfactant (D) includes, for example, a silicone surfactant, a fluorine-based surfactant, etc., and preferably includes a silicone surfactant. The surfactant (D) of the present embodiment may be a single surfactant or may contain two or more surfactants.

[0090] The content 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, even more preferably 0.3 parts by mass or less, when the total content of the resin components in the resin composition is 100 parts by mass.

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

[0092] Examples of the organic solvent (E) of the present 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, and butyl lactate. The organic solvent (E) of the present embodiment may be a single organic solvent, or may contain two or more organic solvents.

[0093] When the resin composition of the present embodiment contains an organic solvent (E), the concentration of all 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 is 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 the present embodiment may further contain, for example, a curing aid, a leveling agent, a colorant, a storage stabilizer, a plasticizer, a filler, inorganic particles, an antidegradant, a wettability improver, an antistatic agent, etc. The content of other components is an appropriate amount.

[0095] The total content of the cyclic olefin resin (A) and the compound (B) having a cyclic ether structure in the resin composition of this embodiment is, when the total content of the resin components in the resin composition is taken as 100% by mass, 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, and the upper limit of the total content is not particularly limited, but is, for example, 100% by mass or less. The total content of the cyclic olefin resin (A) and the compound (B) having a cyclic ether structure in the resin composition of this embodiment is, when the total content of all components in the resin composition is 100 mass%, preferably 10 mass% or more, more preferably 20 mass% or more, even more preferably 30 mass% or more, even more preferably 35 mass% or more, even more preferably 50 mass% or more, even more preferably 70 mass% or more, even more preferably 80 mass% or more, even more preferably 85 mass% or more, even more preferably 90 mass% or more, even more preferably 92 mass% or more, and the upper limit is not particularly limited, but is, for example, less than 100 mass% and 99 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, when the total content of all components in the resin composition is 100% by mass, 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, even more preferably 95% by mass or more, and the upper limit is not particularly limited, but is, for example, 100% by mass or less.

[0097] [Method of producing resin composition] The resin composition of the present embodiment can be obtained, for example, by mixing the components. The film-like resin composition of this embodiment can be obtained, for example, by applying a varnish-like resin composition onto a substrate 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 a resin film alone but also a resin film formed on a substrate film.

[0099] The light transmittance of the resin film of this embodiment at a wavelength of 850 nm is preferably 85% or more, more preferably 90% or more, even more preferably 95% or more, even more preferably 97% or more, and even more preferably 98% or more, from the viewpoint of further improving the light propagation efficiency of the optical waveguide. The light transmittance of the 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 embeddability, 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 light propagation efficiency of the optical waveguide.

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

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

[0103] From the viewpoint of further improving the handleability of the film, the thickness of the film of 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 is preferably 250 μm or less, more preferably 200 μm or less, even more preferably 150 μm or less.

[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, and from the viewpoint of further improving the light 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 the present embodiment preferably further includes a substrate film, and a resin layer is provided on the substrate film. The base film may be, for example, a resin film. The resin constituting the base film is not particularly limited, but it is preferable that the base film contains at least one or more types selected from the group consisting of polyimide and polyethylene terephthalate.

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

[0107] The substrate film of the present embodiment may be subjected to a surface treatment such as an antistatic treatment or a release treatment.

[0108] The film of this embodiment may further include a cover film, which is preferably provided so as to be in direct contact with the resin layer. When the film of the present embodiment includes a base film, the cover film is preferably provided on the surface 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 the varnish-like resin composition of this embodiment to a substrate film and drying it. Examples of the application method include direct application using various coater devices such as a pin coater, a die coater, a comma coater, and a curtain coater, and printing methods such as screen printing.

[0110] [Film Set] The film set of this embodiment includes a first film and a second film, and at least one of the first film and the second film is the film of this embodiment. In the film set of this embodiment, both the first film and the second film are preferably the film of this embodiment.

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

[0112] When the optical waveguide 100 is provided on a substrate 110, the first cladding layer 20 is preferably 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. From the viewpoint of further improving embeddability, 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 light propagation efficiency of the optical waveguide, the thickness 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. From the viewpoint of further suppressing thermal shrinkage of the optical waveguide, 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, and even more preferably 8 μm or more, and 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, even more preferably 30 μm or less, and even more preferably 20 μm or less.

[0113] The material for forming the core layer 30 is not particularly limited, but may be formed from, for example, a resin composition. The resin for forming the core layer 30 may be, for example, a resin used for the core of a known optical waveguide, but preferably contains a cyclic olefin resin, and more preferably contains a norbornene resin. The resin composition for forming the core layer 30 may contain an antioxidant, a photocationic polymerization initiator, 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 is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, even more preferably 50 μm or less.

[0115] A waveguide pattern may be formed in the core layer 30. Methods for forming the waveguide pattern include, for example, exposure, etching, and replication.

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

[0117] The optical waveguide 100 may include other layers in addition to the first cladding layer 20, the core layer 30, and the second cladding layer 40, as long as the excellent performance of the optical waveguide 100 is not affected.

[0118] [Optical / electrical composite substrate] The optical and electrical composite substrate of this embodiment will be described with reference to FIG. The optical / electrical composite substrate 200 includes a substrate 110 and an optical waveguide 100 provided on the substrate 110 .

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

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

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

[0122] The optical-electrical composite substrate 200 can be obtained, for example, by (i) forming a first clad layer 20 on the substrate 110, (ii) forming a core layer 30 on the first clad layer 20, and (iii) forming a second clad layer 40 on the core layer 30. Examples of methods for forming each layer include methods in which films for forming each layer are laminated in order by roll lamination, vacuum roll lamination, flat plate lamination, vacuum flat plate lamination, atmospheric pressing, vacuum pressing, etc.

[0123] [Electronic Components] The electronic component of this embodiment includes the optical / electrical composite substrate of this embodiment. Examples of the electronic component of this embodiment include electronic components in electronic devices such as mobile phones, game machines, router devices, WDM devices, personal computers, televisions, and home servers.

[0124] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

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

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

[0127] <Synthesis of cyclic olefin resin> (Synthesis of Cyclic Olefin Resin (A-1)) 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 into a suitable reaction vessel equipped with a stirrer and a condenser, and dissolved in 1607 g of methyl ethyl ketone and 689 g of toluene. Dissolved oxygen was then removed from the system by nitrogen bubbling, after which the vessel was sealed and reacted at 70 °C for 16 hours. The resulting solution was cooled to room temperature and reprecipitated in a large amount of heptane to obtain a polymer precipitate. The polymer was then filtered off using a suction filter, and the powder was washed with heptane and 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) measured by GPC was 11,000, and the refractive index measured by an Abbe refractometer at 23° C. and 589 nm was 1.51. The cyclic olefin resin (A-1) is a resin containing a structural unit represented by formula (a-1) and a structural unit represented by formula (b-2).

[0128] (Synthesis of Cyclic Olefin Resin (A-2)) 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 into a suitable reaction vessel equipped with a stirrer and a condenser, and dissolved in 2213 g of methyl ethyl ketone and 948 g of toluene. Dissolved oxygen was then removed from the system by nitrogen bubbling, after which the vessel was sealed and reacted at 70 °C for 16 hours. The resulting solution was cooled to room temperature and reprecipitated in a large amount of heptane to obtain a polymer precipitate. The polymer was then filtered off using a suction filter, and the powder was washed with heptane and 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) measured by GPC was 12,000, and the refractive index measured by an Abbe refractometer at 23° C. and 589 nm was 1.51. The cyclic olefin resin (A-2) is a resin containing a structural unit represented by formula (a-1) and a structural unit represented by formula (b-3).

[0129] (Synthesis of Cyclic Olefin Resin (A-3)) 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 into a suitable reaction vessel equipped with a stirrer and a condenser, and dissolved in 2401 g of methyl ethyl ketone and 1029 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 reprecipitated in a large amount of heptane to obtain a polymer precipitate. The polymer was then filtered using a suction filter, and the powder was washed with heptane and dried in a dryer at 60 °C for 24 hours to obtain cyclic olefin resin (A-3). The weight average molecular weight (Mw) of the cyclic olefin resin (A-3) measured by GPC was 6,300, and the refractive index measured by an Abbe refractometer at 23° C. and 589 nm was 1.51. The cyclic olefin resin (A-3) is a resin containing a structural unit represented by formula (a-1), a structural unit represented by formula (b-2), and a structural unit represented by formula (b-3).

[0130] (Synthesis of Cyclic Olefin Resin (A-4)) 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-cyclohexylmaleimide, and 23.0 g (0.1 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed into an appropriately sized reaction vessel equipped with a stirrer and a condenser, and dissolved in 2310 g of methyl ethyl ketone and 990 g of toluene. Dissolved oxygen was removed from the system by nitrogen bubbling, and the vessel was sealed and reacted at 70 °C for 16 hours. The resulting solution was cooled to room temperature and then reprecipitated 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 washed with heptane and then dried in a dryer at 60° C. for 24 hours to obtain a cyclic olefin resin (A-4). The weight average molecular weight (Mw) of the cyclic olefin resin (A-4) measured by GPC was 11,500, and the refractive index of the cyclic olefin resin (A-4) measured by an Abbe refractometer at 23°C and 589 nm was 1.51. The cyclic olefin resin (A-4) is a resin containing a structural unit represented by formula (a-1) and a structural unit represented by formula (b-1).

[0131] (Synthesis of Cyclic Olefin Resin (A-5)) 900 g (5.0 mol) of methyl glycidyl ether norbornene, 242.7 g (2.5 mol) of maleimide, 448.1 g (2.5 mol) of N-cyclohexylmaleimide, and 23.0 g (0.1 mol) of dimethyl 2,2'-azobis(2-methylpropionate) were weighed into an appropriately sized reaction vessel equipped with a stirrer and a condenser, 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. The resulting solution was cooled to room temperature and then reprecipitated in a large amount of heptane to obtain a polymer precipitate. The polymer was then filtered using a suction filter, and the powder was washed with heptane and dried in a dryer at 60 °C for 24 hours to obtain cyclic olefin resin (A-5). The weight average molecular weight (Mw) of the cyclic olefin resin (A-5) measured by GPC was 8,500, and the refractive index of the cyclic olefin resin (A-5) measured by an Abbe refractometer at 23°C and 589 nm was 1.51. The cyclic olefin resin (A-5) is a resin containing a structural unit represented by formula (a-1) and a structural unit represented by formula (b-1).

[0132] (Synthesis of Cyclic Olefin Resin (A-6)) <For Comparative Example> The inside of a reaction vessel equipped with a stirrer and a condenser was first thoroughly purged with nitrogen. Then, 164 g (0.7 mol) of decylnorbornene, 54.1 g (0.3 mol) of methyl glycidyl ether norbornene, and 800 g of toluene were added and heated to 50 °C in an oil bath while stirring. 5 g of a toluene solution of 26.9 g (0.014 mol) of (toluene)Ni(CF) was added and the reaction was continued for 3 hours at 50 °C. The resulting solution was reprecipitated 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 resulting 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 an Abbe refractometer at 23 °C and 589 nm was 1.50. The cyclic olefin resin (A-6) is a resin containing the structural unit (a) but not the structural unit (b).

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

[0134] 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 above (A-5) Cyclic olefin resin synthesized above (A-6) Cyclic olefin resin synthesized above (for comparison) (A-7) JER-1256 (manufactured by Mitsubishi Chemical Corporation, aromatic phenoxy resin) (for comparison) (A-8) Cyclic olefin resin synthesized above

[0136] [ka]

[0137] <Compound (B) Having a Cyclic Ether Structure> (B-1) Celloxide 2021P (manufactured by Daicel Corporation, epoxy compound with an alicyclic structure, liquid at 23°C, refractive index 1.51) (B-2) EHPE-3150 (manufactured by Daicel Corporation, epoxy compound with an alicyclic structure, solid at 23°C, refractive index 1.51) (B-3) Epikote YX-8000 (manufactured by Mitsubishi Chemical Corporation, epoxy compound with an alicyclic structure, liquid at 23°C, refractive index 1.51) (B-4) Denacol EX-321L (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] <Curing agent (C)> (C-1) CPI-310B (San-Apro Co., Ltd., photocationic polymerization initiator) (C-2) San-Aid SI-B5 (manufactured by Sanshin Chemical Industry Co., Ltd., thermal cationic polymerization initiator) (C-3) Curezol C11z (manufactured by Shikoku Chemicals Co., Ltd., imidazole-based compound)

[0140] <Surfactant (D)> (D-1) BYK-333 (BYK Japan Co., Ltd., silicone 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 to 10, 21 and Comparative Examples 1 to 3] (Preparation of Resin Composition) The raw materials formulated according to Table 1 were stirred at room temperature until the raw materials were completely dissolved to obtain a solution, which was then filtered through a PTFE filter with a pore size of 0.2 μm to obtain varnish-like resin compositions of Examples 1 to 10 and 21 and Comparative Examples 1 to 3, respectively.

[0143] (Film Preparation) The resin compositions of Examples 1 to 10, 21 and Comparative Examples 1 to 3 obtained by preparing the above resin compositions were applied as a varnish using an applicator onto a 38 μm thick antistatic treated polyethylene terephthalate substrate so that the thickness after drying would be the thickness of the resin layer listed in Table 1, and then dried at 100°C for 10 minutes.Finally, 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 to 10, 21 and Comparative Examples 1 to 3, respectively.

[0144] [Examples 11 to 20, 22 and Comparative Examples 4 and 5] (Synthesis of polymer for forming core layer) In a glove box filled with dry nitrogen and with moisture and oxygen concentrations both controlled to 1 ppm or less, 7.2 g (40.1 mmol) of hexylnorbornene (HxNB) and 12.9 g (40.1 mmol) of diphenylmethylnorbornene methoxysilane were weighed into a 500 mL vial, to which 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the vial was then sealed with a silicone sealer. Next, 1.56 g (3.2 mmol) of Ni catalyst and 10 mL of dehydrated toluene were weighed into a 100 mL vial, the vial was sealed with a stirrer tip, and the Ni catalyst was thoroughly stirred to completely dissolve, yielding a Ni catalyst solution. 1 mL of the Ni catalyst solution was accurately measured with a syringe and quantitatively injected into the vial containing the two norbornenes dissolved above. Stirring was continued at room temperature for 1 hour, resulting in a significant increase in viscosity. At this point, the stopper was removed, and 60 g of tetrahydrofuran (THF) was added and stirred to obtain a reaction solution. A 100 mL beaker was charged with 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (30% concentration), and 30 g of ion-exchanged water, and the resulting mixture was stirred to prepare an aqueous solution of peracetic acid. The entire amount of the aqueous solution of peracetic acid was then added to the reaction solution and stirred for 12 hours to reduce Ni. Next, the reaction solution was transferred to a separatory funnel, and after removing the lower aqueous layer, 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. After allowing the mixture to stand and completely separate into two layers, the aqueous layer was removed. This water washing process was repeated three times, and the oil layer was then dropped into a large excess of acetone to reprecipitate the resulting polymer. The filtrate was separated by filtration and then heated and dried for 12 hours in a vacuum dryer set at 60°C to obtain the core layer-forming polymer.

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

[0146] (Preparation of Resin Composition for Forming Core Layer) 10 g of the purified core layer-forming polymer was weighed into a 100 mL glass container, and 30 g of methylcyclohexane, 2.4 g of an oxetane compound (manufactured by Toagosei Co., Ltd., product name: OXT-213), 0.8 g of an epoxy compound (manufactured by Daicel Corporation, product name: CELLOXIDE 2021P), 0.03 g of a photocationic polymerization initiator (manufactured by San-Apro Co., Ltd., product name: CPI-310B), and 0.1 g of an antioxidant (manufactured by BSF, product name: Irganox1076) were added thereto and dissolved uniformly. The mixture was then filtered through a 0.2 μm PTFE filter to obtain a core layer-forming resin composition.

[0147] (Preparation of dry film for core layer formation) The obtained core layer-forming resin composition was applied to a release-treated PET film using an applicator so that the film would have a dry thickness of 40 μm. After application, the film was placed in a dryer at 45° C. for 5 minutes to completely remove the solvent, yielding a dry film for core layer formation.

[0148] (Creation of core layer) The obtained dry film for forming the core layer was exposed to light at a dose of 100 mJ / cm using a direct imaging exposure machine (manufactured by SCREEN Co., Ltd., product name: LI-9000). 2 The substrate was irradiated with ultraviolet light at 1000 W at 2000 W, creating 20 lines and spaces with a length of 9 cm, 10 μm in exposed areas, and 50 μm in unexposed areas. The substrate was then placed in a 160°C oven for 1 hour to obtain a core layer. It was confirmed that the obtained core layer had a clear waveguide pattern (multiple cores) with a rectangular cross section.

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

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

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

[0152] Next, the second clad layer in laminate 3 was laminated to the polyimide substrate (manufactured by UBE Corporation, product name: Upilex 25S, thickness 25 μm) using a vacuum laminator under the same conditions as for laminating laminate 1 so that they were in contact with each other, thereby obtaining laminate 4, whose layer structure was "double-sided copper-clad laminate / first clad layer / core layer / second clad layer / polyimide substrate."

[0153] The obtained laminate 4 was heat-treated in an oven at 180° C. for 1 hour to obtain the photoelectric composite substrates of Examples 11 to 20 and 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 Coatability> The appearance of the films of Examples 1 to 10 and 21 and Comparative Examples 1 to 3 was observed, and samples with no appearance abnormalities such as standard B were rated as A, and samples with appearance abnormalities (uneven coating, cloudiness, repelling, cracks, etc.) were rated as B.

[0156] <Evaluation of refractive index> The OPP cover film was peeled off from the films of Examples 1 to 10 and 21 and Comparative Examples 1 to 3, 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). The refractive index is preferably low from the viewpoint of increasing the difference in refractive index between the core layer and the film.

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

[0158] <Embeddability evaluation> A 50 μm-thick double-sided copper-clad laminate (CCL) with a 100 μm diameter via hole was prepared. The OPP cover film of each of the films in Examples 1 to 10, 21, and Comparative Examples 1 to 3 was peeled off, and the film was attached to the CCL so that the resin layer formed from the resin composition faced the CCL. The film was then laminated using a laminator at a temperature of 100°C, a pressure of 5.0 MPa, and a time of 2 minutes. The via holes in the resulting substrates were observed under a microscope, and samples that were filled without voids were rated as A, samples with insufficient filling were rated as B, and samples with poor filling, such as bleeding, were rated as C.

[0159] <Optical loss evaluation> The optoelectronic composite substrates of Examples 11 to 20 and 22 and Comparative Examples 4 and 5 were cut by dicing on both sides so that the length of the patterned portion was 7 cm, to obtain samples for evaluating optical loss. The propagation loss of the optical loss evaluation samples was evaluated in accordance with 4.6.2.1 Cutback Method of "Test Methods 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 a propagation loss of less than 1 dB were rated as A, samples with a propagation loss of 1 dB to 3 dB as B, and samples with a propagation loss of more than 3 dB 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 can be seen from Table 1, the embeddability evaluation results for all of the films of the examples were good. Furthermore, the films of the examples did not show a decrease in light transmittance at a wavelength of 850 nm, as did the film of Comparative Example 2. That is, it can be seen that the resin composition of the present embodiment can improve embeddability while suppressing a decrease in light transmittance.

[0164] As can be seen from Table 2, the optical and electrical composite substrates of the examples all had good optical loss evaluation results, which means that the optical and electrical composite substrate of this embodiment can suppress propagation loss.

[0165] This application claims priority based on Japanese Patent Application No. 2023-166734, filed September 28, 2023, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0166] 20 First cladding layer 30 Core Layer 40 Second cladding layer 50 Mirror on the light-emitting element side 60 Mirror on the light receiving element side 100 optical waveguide 110 Substrate 120 Light-emitting element 130 Photodetector 140a, 140b vias 200 Optical and electrical composite substrate

Claims

1. A resin composition that can be used for an optical waveguide clad, 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 the following formula (a-1): The structural unit (b) is one or more selected from the group consisting of a structural unit represented by the following formula (b-1), a structural unit represented by the following formula (b-2), and a structural unit represented by the following formula (b-3): 【Chemical 1】 (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. 【Chemistry 2】 (In formula (b-1), R １１ represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms. 【Chemistry 3】 【Chemistry 4】 (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.

2. 2. The resin composition according to claim 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 of all structural units in the cyclic olefin resin (A) is 100 mol %.

3. The resin composition according to claim 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 claims 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 the resin components in the resin composition is 100 parts by mass.

5. The resin composition according to any one of claims 1 to 4, further comprising a compound (B) having a cyclic ether structure.

6. The resin composition according to claim 5, wherein the compound (B) having a cyclic ether structure comprises at least one or more compounds selected from the group consisting of epoxy compounds and oxetane compounds.

7. The resin composition according to claim 5 or 6, wherein the compound (B) having a cyclic ether structure contains an alicyclic structure in the molecule.

8. The resin composition according to any one of claims 5 to 7, wherein the compound (B) having a cyclic ether structure contains two or more cyclic ether structures in the molecule.

9. The resin composition according to any one of claims 5 to 8, wherein the compound (B) having a cyclic ether structure is liquid at 23°C.

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

11. The resin composition according to any one of claims 5 to 10, wherein the content of the compound (B) having a 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 the resin components in the resin composition is 100 parts by mass.

12. The resin composition according to any one of claims 1 to 11, further comprising a curing agent (C).

13. The resin composition according to claim 12, wherein the curing agent (C) comprises a cationic polymerization initiator.

14. The resin composition according to claim 13 , wherein the cationic polymerization initiator comprises a photocationic polymerization initiator.

15. The resin composition according to claim 13 or 14, wherein the cationic polymerization initiator comprises a thermal cationic polymerization initiator.

16. The resin composition according to any one of claims 12 to 15, wherein the curing agent (C) comprises an imidazole-based compound.

17. The resin composition according to any one of claims 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 claims 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 made of the resin composition according to any one of claims 1 to 18, The resin film has 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 for an optical waveguide clad, A film comprising a resin layer formed from the resin composition according to any one of claims 1 to 18.

22. Further, a base film is provided, The film according to claim 21 , having the resin layer on the substrate 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 any one of claims 21 to 23, wherein the film is a dry film.

25. A film set that can be used for an optical waveguide clad, a first film and a second film; A film set, wherein at least one of the first film and the second film is the film according to any one of claims 21 to 24.

26. An optical waveguide in which a first clad layer, a core layer, and a second clad layer are laminated in this order, An optical waveguide, wherein at least one of the first clad layer and the second clad layer comprises the resin composition according to any one of claims 1 to 18.

27. A substrate; An optical / electrical composite substrate comprising: the optical waveguide according to claim 26 provided on the substrate.

28. An electronic component comprising the optical-electrical composite substrate according to claim 27.

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