Resin composition, resin membrane, film, film set, optical waveguide, photoelectric composite substrate, and electronic component

Abstract

The present invention pertains to a resin composition that can be used in optical waveguide cladding. The resin composition 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 units selected from the group consisting of structural units represented by formula (b-1), structural units represented by formula (b-2), and structural units represented by formula (b-3).

Description

Resin composition, resin film, film, film set, optical waveguide, photoelectric composite substrate and electronic component

[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.

[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] The optical / electrical composite substrate may have an optical waveguide provided on a substrate. Techniques relating to the optical / electrical composite substrate include those described in Patent Documents 1 and 2, for example.

[0004] Patent Document 1 describes an opto-electrical hybrid board including a flexible circuit board having electrical wiring with mounting pads formed on the surface of an insulating layer, a device mounted on the mounting pads, and an optical waveguide laminated on the back surface of the insulating layer, wherein the flexible circuit board is a flexible double-sided circuit board having electrical wiring also formed on the back surface of the insulating layer, and a metal reinforcing layer is plated on at least a portion of the electrical wiring on the back surface corresponding to the mounting pads, and the optical waveguide is in contact with the metal reinforcing layer. Patent Document 1 describes an opto-electrical hybrid board in which the metal reinforcing layer is adhered to the insulating layer of the flexible circuit board without an adhesive layer, and the metal reinforcing layer prevents deformation due to a pressure load during device mounting, thereby providing an opto-electrical hybrid board in which the device is properly mounted.

[0005] Patent Document 1 describes preparing a substrate having copper foil 21 formed on both sides of an insulating layer 1 made of a resin such as polyimide, and forming through holes 1a and via holes 1b for optical paths in the substrate (see paragraph 0023 of Patent Document 1). Patent Document 1 also describes a flexible double-sided circuit board E having a metal reinforcing layer M formed thereon (see paragraph 0028 of Patent Document 1). The flexible double-sided circuit board E includes the substrate. Patent Document 1 also describes forming an undercladding layer 6 on the back side of the flexible double-sided circuit board E in contact with the metal reinforcing layer M that covers the electrical wiring 2B on the back side. Examples of molding materials for the undercladding layer 6 include photosensitive resins and thermosetting resins (see paragraph 0029 of Patent Document 1). Figures 4 to 6 of Patent Document 1 show that the molding material for the undercladding layer 6 is filled into recesses formed in the flexible double-sided circuit board E having the metal reinforcing layer M formed thereon.

[0006] Patent Document 2 describes an optoelectronic 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 is formed with external connection terminals for mounting optical elements and / or package substrates on which optical elements are mounted, and at least one of the flex sections is formed with optical wiring. It is described that the optoelectronic wiring board in Patent Document 2 can suitably process large amounts of information and high-speed information processing 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 describes that the resin layer 221a constitutes part of the optical signal transmitting regions 242a, 242b (see paragraph 0033 of Patent Document 2).

[0009] JP 2014-238455 A JP 2006-140233 A

[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, "embedding ability" 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.

[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 usable for an optical waveguide clad, comprising a cyclic olefin resin (A), wherein the cyclic olefin resin (A) comprises a structural unit (a) and a structural unit (b), wherein the structural unit (a) is a structural unit represented by the following 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 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). (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 (b-1), R １１ represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms. (In formula (b-3), R ２１ and R ２２each independently represents a hydrogen atom or an organic group having 1 to 30 carbon atoms.) [2] The resin composition according to [1] above, 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 of [1] to [3] above, 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 of [1] to [4] above, 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 comprises at least one or two 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 comprises 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 comprises two or more cyclic ether structures in the molecule. [9] The resin composition according to any one of [5] to [8] above, 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 the resin components in the resin composition is 100 parts by mass.

[12] The resin composition according to any one of [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-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 the 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 to 1.55.

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

[18] , wherein the resin film has a light transmittance of 85% or more at a wavelength of 850 nm.

[20] The resin film according to

[19] , wherein the resin film has a thickness of 1 μm or more and 150 μm or less.

[21] A film usable for an optical waveguide clad, comprising a resin layer formed from the resin composition according to any one of [1] to

[18] .

[22] The film according to

[21] , further comprising a substrate film, wherein the resin layer is disposed on the substrate film.

[23] The film according to

[22] , wherein the resin constituting the substrate film includes at least one or more resins selected from the group consisting of polyimide and polyethylene terephthalate.

[24] The film according to any one of

[21] to

[23] , wherein the film is a dry film.

[25] A film set usable for an optical waveguide clad, comprising a first film and a second film, wherein at least one of the first film and the second film is the film according to any one of

[21] to

[24] .

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

[18] .

[27] An optical / electrical composite substrate comprising: a substrate; and the optical waveguide described in

[26] provided on the substrate.

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

[27] .

[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.

[0017] 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.

[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 schematically illustrating an example of the structure of an optical / electrical composite substrate according to this embodiment. As shown in FIG. 1 , an optical / electrical composite substrate 200 includes 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 embedded 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 is transmitted through the core layer 30. After that, it 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 clad layer 20, and integrating them by heating and pressurizing. In the integration step, the via 140 needs to be embedded in the first clad layer 20.

[0022] According to the inventors' investigations, it was found that conventional materials for forming optical waveguide claddings cannot sufficiently fill the optical waveguide claddings 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 (i.e., the core layer side of the optical waveguide cladding) or voids in the vias. Furthermore, it was found that when the above-mentioned depressions or voids occur in the optoelectronic composite substrate, optical loss occurs at the interface of the depressions or voids. In other words, 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 filled in the 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 at 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 the present 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). 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]

[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]

[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]

[0032]

[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 on 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 to 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 with an ultraviolet-visible spectrophotometer for a resin film made of the resin composition and having a thickness of 25 μm. A resin film made of the resin composition and having a thickness of 25 μm can be produced, for example, by applying the resin composition to 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]

[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 ４Examples of the organic group constituting the aryl group include at least one selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, cycloalkyl groups, organic groups having a carboxyl group, and organic groups having a heterocycle. Examples of the alkyl group include at least one selected from the group consisting of methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, tert-butyl groups, pentyl groups, neopentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, and dodecyl groups. Examples of the alkenyl group include at least one selected from the group consisting of allyl groups, pentenyl groups, and vinyl groups. Examples of the alkynyl group include ethynyl groups. Examples of the alkylidene group 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 and phenethyl groups. Examples of alkaryl groups include at least one selected from the group consisting of tolyl 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 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 In addition, from the viewpoint of further improving the heat resistance and strength of the cured product of the resin composition, it is preferable that at least one selected from the group consisting of 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 ４ preferably 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]

[0049] In formula (b-1), R １１represents 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 R may be, for example, 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, and a cycloalkyl group. 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]

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

[0056]

[0057] In formula (b-3), R ２１and 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 ２１ and R ２２ Examples of the organic group constituting R include at least one selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, alkylidene groups, aryl groups, aralkyl groups, alkaryl groups, cycloalkyl groups, groups having an acryloyl group, and groups having a methacryloyl group. 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 ２２is 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 taken as 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, 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 the cyclic olefin resin (A) means the refractive index measured with an Abbe refractometer under 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 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 taken as 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 the present embodiment, when the total content of all components of the resin composition is taken as 100% by mass, 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 is preferably less than 100% by mass, more preferably 80% by mass or less, 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 a known method. More specifically, it can be produced by polymerizing monomers capable of forming each structural unit by any method. Here, 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. Examples of monomers capable of forming the structural unit represented by formula (b-2) include 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 this embodiment preferably further contains a compound (B) having a cyclic ether structure. Here, the compound (B) having a cyclic ether structure of 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 bonding 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, 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 the compound (B) having a cyclic ether structure means the refractive index measured with an Abbe refractometer under conditions of 23°C and 589 nm.

[0078] When the total content of the resin components in the resin composition is taken as 100 parts by mass, the content of the compound (B) having a cyclic ether structure in the resin composition of this embodiment is, from the viewpoint of further improving embeddability, 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, and is preferably 80 parts by mass or less, 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). Examples of the curing agent (C) include at least one selected from the group consisting of a thermal polymerization initiator, a photopolymerization initiator, an amine compound, and the like.

[0081] The curing agent (C) preferably contains a cationic polymerization initiator. Examples of the cationic polymerization initiator include a photocationic 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 contains a sulfonium salt type polymerization initiator.

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

[0085] 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 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.

[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 is 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, when the total content of the resin components in the resin composition is taken as 100 parts by mass, 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 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.

[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 this embodiment preferably further contains a surfactant (D). The surfactant (D) includes, for example, a silicone-based surfactant, a fluorine-based surfactant, etc., and preferably includes a silicone-based surfactant. The surfactant (D) of this embodiment may be a single surfactant or may include two or more surfactants.

[0090] The content of the surfactant (D) contained in the resin composition of this embodiment is, when the total content of the resin components in the resin composition is 100 parts by mass, 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.

[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 the organic solvent (E), it can be made into a varnish-like resin composition.

[0092] Examples of the organic solvent (E) of 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, etc. The organic solvent (E) of this 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 the 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 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 Components> 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 the 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. 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 the present 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 the present 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 95 mass% or more, and the upper limit is not particularly limited, but is, for example, 100 mass% or less.

[0097] [Method for Producing Resin Composition] The resin composition of the present embodiment can be obtained, for example, by mixing the respective components. The resin composition of the present embodiment in a film form 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] From the viewpoint of further improving the light propagation efficiency of the optical waveguide, the resin film of this embodiment has a light transmittance of 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 for a wavelength of 850 nm. The light transmittance of the resin film for 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 the present embodiment includes a resin layer formed from the resin composition of the present embodiment. The film of the present 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 this embodiment preferably further includes a substrate film, and a resin layer is provided on the substrate film. The substrate film may be, for example, a resin film. The resin constituting the substrate film is not particularly limited, but preferably includes at least one or more resins 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. The cover film is preferably provided so as to be in direct contact with the resin layer. When the film of this 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 the present 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 the present embodiment. In the film set of the present embodiment, it is preferable that both the first film and the second film are the film of the present embodiment.

[0111] [Optical Waveguide] The optical waveguide of this embodiment will be described with reference to Fig. 1. 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 laminated 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, it is preferable that both the first clad layer 20 and the second clad layer 40 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 be 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, 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. 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, and may be, 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, etc.

[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 / electrical composite substrate of this embodiment will be described with reference to Fig. 1. 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 substrate (not shown) on the surface of the second cladding layer 40 opposite to the core layer 30 .

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

[0122] The photoelectric composite substrate 200 can be obtained, for example, by (i) forming a first cladding layer 20 on the 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. 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 lamination, vacuum flat lamination, atmospheric pressing, vacuum pressing, or the like.

[0123] [Electronic Component] 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 consoles, 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 may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[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 reaction vessel of an appropriate size equipped with a stirrer and a cooling tube, and dissolved in 1607 g of methyl ethyl ketone and 689 g of toluene. Next, dissolved oxygen in the system was removed 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 further washed with heptane and 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) 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 reaction vessel of an appropriate size equipped with a stirrer and a condenser, and dissolved in 2,213 g of methyl ethyl ketone and 948 g of toluene. Next, dissolved oxygen in the system was removed 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 further washed with heptane and 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) 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 reaction vessel of appropriate size equipped with a stirrer and a condenser, and dissolved in 2401 g of methyl ethyl ketone and 1029 g of toluene. Next, dissolved oxygen in the system was removed by nitrogen bubbling, and the vessel was sealed, and the reaction was carried out 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 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 cyclic olefin resin (A-3). The weight average molecular weight (Mw) of 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 a reaction vessel of appropriate size equipped with a stirrer and a condenser, and dissolved in 2310 g of methyl ethyl ketone and 990 g of toluene. Next, dissolved oxygen in the system was removed 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. The polymer was then 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 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 an Abbe refractometer under conditions of 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 a reaction vessel of an appropriate size equipped with a stirrer and a condenser, and dissolved in 2636 g of methyl ethyl ketone and 1130 g of toluene. Next, dissolved oxygen in the system was removed 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 further washed with heptane and 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 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 atmosphere inside a reaction vessel equipped with a stirrer and a condenser was first thoroughly purged with nitrogen, and 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 charged, and the mixture was heated to 50°C in an oil bath while stirring. ６ F ５ ) ２6.9 g (0.014 mol) of a toluene solution (5 g) was added, and the mixture was further reacted at 50°C for 3 hours. 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 dried in vacuum 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 under conditions of 23°C and 589 nm was 1.50. The cyclic olefin resin (A-6) is a resin that contains the structural unit (a) but does not contain 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 reaction vessel of an appropriate size equipped with a stirrer and a condenser, and dissolved in 3949 g of methyl ethyl ketone and 1693 g of toluene. Next, dissolved oxygen in the system was removed 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 further washed with heptane and 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 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 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]

[0137] <Compounds (B) Having a Cyclic Ether Structure> (B-1) CELLOXIDE 2021P (manufactured by Daicel Corporation, epoxy compound having an alicyclic structure, liquid at 23°C, refractive index 1.51) (B-2) EHPE-3150 (manufactured by Daicel Corporation, epoxy compound having an alicyclic structure, solid at 23°C, refractive index 1.51) (B-3) EPICOAT YX-8000 (manufactured by Mitsubishi Chemical Corporation, epoxy compound having an 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]

[0139] <Curing Agent (C)> (C-1) CPI-310B (manufactured by 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) Curesol C11z (manufactured by Shikoku Chemical Industry Co., Ltd., imidazole-based compound)

[0140] <Surfactant (D)> (D-1) BYK-333 (manufactured by BYK Japan K.K., 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 Compositions) The raw materials formulated according to Table 1 were 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 varnish-like resin compositions of Examples 1 to 10, 21 and Comparative Examples 1 to 3, respectively.

[0143] (Film Production) The resin compositions of Examples 1 to 10, 21 and Comparative Examples 1 to 3 obtained by the above-mentioned resin composition production were applied to a 38 μm thick antistatic treated polyethylene terephthalate substrate as a varnish using an applicator so that the thickness after drying would be the thickness of the resin layer shown 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, and the films of Examples 1 to 10, 21 and Comparative Examples 1 to 3 were obtained, respectively.

[0144] [Examples 11-20, 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 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, 60 g of dehydrated toluene and 11 g of ethyl acetate were added, and the vial was 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, 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 therein. After stirring at room temperature for 1 hour, a significant increase in viscosity was observed. At this point, the stopper was removed, and 60 g of tetrahydrofuran (THF) was added and stirred to obtain a reaction solution. 9.5 g of acetic anhydride, 18 g of hydrogen peroxide (30% concentration), and 30 g of ion-exchanged water were added to a 100 mL beaker and stirred to prepare an aqueous solution of peracetic acid. Next, the entire amount of the aqueous solution of peracetic acid was added to the reaction solution and stirred for 12 hours to perform a Ni reduction treatment. Next, the reaction solution after completion of the treatment was transferred to a separatory funnel, and the lower aqueous layer was removed. 100 mL of a 30% aqueous solution of isopropyl alcohol was added and vigorously stirred. After allowing to stand and allowing complete separation into two layers, the aqueous layer was removed. This water washing process was repeated a total of 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 a polymer for forming a core layer.

[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. 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 Core Layer-Forming Resin Composition) 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 Ltd., product name: CPI-310B), and 0.1 g of an antioxidant (manufactured by BSF, product name: Irganox 1076) were added thereto and dissolved uniformly, followed by filtration 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 resin composition for core layer formation was applied to a release-treated PET film using an applicator so that the film thickness after drying would be 40 μm. After coating, the film was placed in a dryer at 45° C. for 5 minutes to completely remove the solvent, thereby obtaining a dry film for core layer formation.

[0148] (Preparation of Core Layer) The obtained dry film for forming a core layer was exposed to light at an exposure dose of 100 mJ / cm using a direct imaging type exposure machine (manufactured by SCREEN Co., Ltd., product name: LI-9000). ２ The substrate was irradiated with ultraviolet light of 1000 W at 1000 W at 2 ...

[0149] (Preparation of photoelectric composite substrate) In preparing the photoelectric composite substrate, the first clad layer film and the second clad layer film refer to the clad films listed in Table 2. The types of clad listed in Table 2 refer to the types of clad 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 double-sided copper-clad laminate and the first clad layer were laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., product name: CVP-300) under conditions of temperature: 140°C, pressure: 0.5 MPa, and time: 120 seconds so that the double-sided copper-clad laminate and the first clad layer were in contact, to obtain a laminate. After peeling off the PET film from the first clad layer film, a direct imaging exposure machine (manufactured by SCREEN Co., Ltd., product name: LI-9000) was used to expose the first clad layer to an exposure dose of 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] The core layer in the core layer-forming dry film after the above-described treatment (preparation of core layer) was subjected to oxygen plasma treatment, and then laminated using a vacuum laminator under the same conditions as for the lamination treatment of laminate 1 so that the first clad layer and core layer in laminate 1 were in contact with each other. The PET film derived from the core layer-forming dry film 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 treatment of Laminate 1 so that the core layer and the second clad layer in Laminate 2 were in contact with each other. The PET film derived from the second clad layer film was peeled off, and Laminate 3 having a layer structure of "double-sided copper-clad laminate / first clad layer / core layer / second clad layer" was obtained.

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

[0153] The resulting 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] Evaluation methods for the Examples and Comparative Examples will be 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 that had no appearance abnormalities such as those in standard B were rated as A, and samples that had 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). A lower refractive index is preferable from the viewpoint of increasing the difference in refractive index from the core layer.

[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 by the resin composition was laminated on a glass slide under conditions of temperature: 100 ° C., pressure: 0.5 MPa, and time: 2 minutes, with the glass slide being the glass slide side. Then, the substrate film was peeled off to obtain a sample for transmittance measurement (glass slide with resin composition). Subsequently, a 100% correction was performed with a glass slide inserted into both the background slot and the sample slot using an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, product name: V-670), and the glass slide on the measurement slot side was replaced with the transmittance measurement sample. The light transmittance [%] at a wavelength of 850 nm was measured in the transmittance measurement mode.

[0158] <Evaluation of Embeddability> 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 of 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 after filling were rated as C.

[0159] <Optical Loss Evaluation> For the optoelectronic composite substrates of Examples 11 to 20, and 22 and Comparative Examples 4 and 5, both sides were diced so that the length of the patterned portion was 7 cm, to obtain samples for optical loss evaluation. For the optical loss evaluation samples, the propagation loss was evaluated in accordance with the cutback method in 4.6.2.1 of the "Test Methods for Polymer Optical Waveguides (JPCA-PE02-05-01S-2008)." Note that light with a wavelength of 850 nm was used for the measurement. Based on the obtained results, samples with a propagation loss of less than 1 dB were evaluated 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]

[0162]

[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 experience 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. That is, it can be seen 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 by reference.

[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 Light-receiving element 140a, 140b Vias 200 Opto-electrical composite substrate

Claims

1. A resin composition usable for an optical waveguide clad, comprising a cyclic olefin resin (A), the cyclic olefin resin (A) comprising a structural unit (a) and a structural unit (b), the structural unit (a) being a structural unit represented by the following formula (a-1), and the structural unit (b) being 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): (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 (b-1), R １１ represents a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms. (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 described in 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. A resin composition described in 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 includes 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. A resin composition described in 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) contains an imidazole compound.

17. A resin composition described in 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 the 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, wherein 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, comprising a resin layer formed from the resin composition according to any one of claims 1 to 18.

22. The film according to claim 21, further comprising a base film, and the resin layer is provided on the base film.

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

24. The film of 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, comprising a first film and a second film, at least one of the first film and the second film being a film according to any one of claims 21 to 24.

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

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

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

Images