Resin wiring board and stretchable device

Abstract

A resin wiring board (1) has a resin substrate (11) with a Young's modulus of 30 N / mm2 or less, and a wiring pattern (21) formed on the resin substrate (11). A resin component included in the resin substrate (11) preferably includes a structural unit derived from a compound that has a fluorene skeleton. A resin component included in the resin substrate may include a structural unit derived from a compound that has a urethane bond and a polymerizable unsaturated bond.

Description

Resin wiring substrate and stretchable device

[0001] The present invention relates to a resin wiring substrate and a stretchable device. This application claims priority to Japanese Patent Application No. 2023-187056, filed on October 31, 2023, the contents of which are incorporated herein by reference.

[0002] Wearable devices have attracted attention in a wide range of fields, including sports science and healthcare. It is desirable for wearable devices to be comfortable to wear. Therefore, it is desirable for them to be stretchable so that they can be worn on the object they are attached to. In this specification, devices with such characteristics are referred to as stretchable devices, regardless of their intended use.

[0003] Patent Document 1 describes an epoxy resin sheet that has recovery after stretching, in which the hysteresis loss after maintaining 50% elongation for 2 seconds in a tensile mode is 40% or less, as measured in accordance with JIS K 7312: 1996. Patent Document 1 also describes a stretchable member and a flexible member that include an epoxy resin sheet.

[0004] Patent Document 2 describes a laminate having a release film on one side of a resin film and a release film on the other side, wherein the resin film contains a segment having an acrylate structure and a segment having a urethane structure, and the resin film has a storage modulus of 0.5 MPa or more and 55 MPa or less and a loss tangent of 0.8 or less under conditions of a temperature of 25°C and a frequency of 1 Hz.

[0005] Patent Document 3 describes a bendable wiring board having a film made of polyurethane that can be synthesized by reacting a long-chain polyol with a polyisocyanate, and that has a temperature at which a storage modulus of 1 MPa is reached by dynamic viscoelasticity measurement of 155°C or higher, a storage modulus of 20 to 200 MPa at 25°C, a tensile strength of 20 to 80 MPa, and a breaking elongation of 500 to 900%, and circuit wiring formed in contact with the surface of the film.

[0006] Patent Document 4 describes a urethane (meth)acrylate obtained by reacting a compound having a fluorene skeleton represented by formula (1) with a (meth)acrylic compound having an isocyanate group, in which the (meth)acrylic compound having an isocyanate group is a mono(meth)acryloyloxyalkyl isocyanate or a di(meth)acryloyloxyalkyl isocyanate.

[0007] Patent Document 5 describes a medical curable composition containing at least one biscresoxyethanol fluorene compound represented by formula (1) and a polyfunctional acrylic monomer polymerizable with the biscresoxyethanol fluorene compound.

[0008] Japanese Patent Application Laid-Open No. 2023-32668 Japanese Patent Application Laid-Open No. 2022-59159 International Publication No. 2020 / 090634 Japanese Patent No. 5608268 Japanese Patent No. 3645722

[0009] The resin wiring board preferably has a low Young's modulus and low strength so that a stretchable device that is comfortable to wear can be formed. Therefore, when manufacturing a resin wiring board, it is preferable to use a resin base material with a low Young's modulus on which a wiring pattern is formed.

[0010] The present invention has been made in view of the above-mentioned problems, and aims to provide a resin wiring board with a low Young's modulus and low strength, and a stretchable device including the same.

[0011] In order to solve the above problems, the following means is provided: A resin wiring board according to one aspect of the present invention has a Young's modulus of 30 N / mm ２ The present invention includes a resin substrate and a wiring pattern formed on the resin substrate.

[0012] The resin wiring board of the present invention has a Young's modulus of 30 N / mm ２The resin wiring board of the present invention has the following resin base material and a wiring pattern formed on the resin base material. Therefore, the resin wiring board of the present invention can be preferably used as a material for a stretchable device that has comfortable wearability. Furthermore, since the stretchable device of the present invention includes the resin wiring board of the present invention, it has comfortable wearability.

[0013] 2A and 2B are schematic diagrams illustrating an example of a stretchable device of the present invention comprising a resin wiring board of the present invention. Fig. 2A is a cross-sectional view of the stretchable device shown in Fig. 1 taken along line A-A' in Fig. 1. Fig. 2B is a cross-sectional view of the stretchable device shown in Fig. 1 taken along line B-B' in Fig. 1. Figs. 3A to 3H are process diagrams illustrating an example of a method for manufacturing the stretchable device shown in Fig. 1. Fig. 4 shows infrared absorption (IR) spectra of resin substrate 8 and resin substrate 18.

[0014] In order to solve the above problems and to obtain a resin wiring substrate capable of forming a stretchable device that is comfortable to wear, the inventors of the present invention have focused on the Young's modulus of the resin substrate in a resin wiring substrate having a wiring pattern formed on the resin substrate and have conducted extensive research. As a result, it has been found that the Young's modulus of the resin substrate is 30 N / mm ２ The present invention has been conceived based on the discovery that the following is sufficient. The present invention includes the following aspects.

[0015] [1] Young's modulus 30 N / mm ２ A resin wiring board having a resin base material as described below and a wiring pattern formed on the resin base material.

[0016] [2] The resin wiring board according to [1], wherein the resin component contained in the resin base material contains a structural unit derived from a compound having a fluorene skeleton. [3] The resin wiring board according to [2], wherein the proportion of the structural units derived from the compound having a fluorene skeleton among the structural units derived from monomers contained in the resin component contained in the resin base material is 30 mass % or more.

[0017] [4] The resin wiring board according to [1], wherein the resin component contained in the resin base material contains a structural unit derived from a compound having a urethane bond and a polymerizable unsaturated bond. [5] The resin wiring board according to [4], wherein the resin component contained in the resin base material contains a structural unit derived from a (meth)acrylic acid alkyl ester. [6] The resin wiring board according to [5], wherein the proportion of the structural units derived from the (meth)acrylic acid alkyl ester among the structural units derived from monomers contained in the resin component contained in the resin base material is 21% by mass to 44% by mass.

[0018] [7] The resin substrate contains a resin component and a filler, and the content of the filler in the resin substrate is 5 parts by mass to 30 parts by mass with respect to 100 parts by mass of the resin component contained in the resin substrate. [4] The resin wiring board according to.

[0019] [8] The resin wiring board according to [1], wherein the resin component contained in the resin base material contains a structural unit derived from a reversible addition-fragmentation chain transfer agent. [9] The resin wiring board according to [1], wherein the resin component contained in the resin base material contains a structural unit derived from a compound having a siloxane bond and a polymerizable unsaturated bond.

[0020]

[10] The resin wiring board according to [1], wherein the wiring pattern has, in a cross-sectional view, an embedded portion made of metal formed along a recess formed on the first surface of the resin base material, and an exposed portion made of metal exposed from the first surface.

[11] A stretchable device comprising the resin wiring board according to any one of [1] to

[10] .

[0021] The resin wiring board and stretchable device of this embodiment will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity. Therefore, the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited to them. Appropriate modifications can be made within the scope of the present invention.

[0022] [Stretchable device] Fig. 1 is a plan view schematic diagram for explaining an example of a stretchable device of the present invention comprising a resin wiring board of the present invention. Fig. 2(a) is a cross-sectional view of the stretchable device shown in Fig. 1 cut along line A-A' shown in Fig. 1. Fig. 2(b) is a cross-sectional view of the stretchable device shown in Fig. 1 cut along line B-B' shown in Fig. 1.

[0023] The stretchable device of this embodiment shown in Figures 1, 2(a), and 2(b) includes a stretchable resin wiring substrate 1. The resin wiring substrate 1 has a stretchable resin base material 11 and a wiring pattern 21 formed on the resin base material 11. The resin wiring substrate 1 and the resin base material 11 of this embodiment have a strip-like shape. As shown in Figures 1 and 2(b), two electronic components 41 are arranged on a first surface 11a of the resin base material 11 arranged approximately at the center in the longitudinal direction of the resin wiring substrate 1.

[0024] (Resin substrate 11) The resin substrate 11 is in a sheet form and has a Young's modulus of 30 N / mm ２ The Young's modulus of the resin substrate 11 is 20 N / mm ２ Preferably, it is 10 N / mm or less. ２ It is more preferable that the Young's modulus of the resin base material 11 is 0.2 N / mm or less. This is because the resin wiring board 1 can be used to form a stretchable device that is more comfortable to wear. ２ It is preferable that the strength is 0.4 N / mm or more. ２ The above is more preferable, because it is easy to obtain a resin wiring board 1 with good durability against stretching, in which the stretchability is not easily deteriorated even when stretched repeatedly.

[0025] The resin substrate 11 contains a resin component made of a resin for substrate and a filler contained as needed. The resin substrate 11 preferably contains a filler. The Young's modulus is 30 N / mm ２ The following resin substrate 11 is likely to lose its stretchability due to repeated stretching. When the resin substrate 11 contains a filler, it is likely to have good stretch durability, in which the stretchability is resistant to deterioration even when stretched repeatedly.

[0026] "Substrate Resin" Examples of the substrate resin, which is a resin component contained in the resin substrate 11, include epoxy-based resins, urethane-based resins, urea-based resins, polyurethane-urea-based resins, (meth)acrylic acid-based resins, polyacrylic resins, silicone-based resins, diene-based resins, polyester-based resins, polyether-based resins, polyamide-based resins, and polystyrene-based resins.

[0027] In this specification, the term "(meth)acrylic acid" encompasses both "acrylic acid" and "methacrylic acid." Furthermore, the term "(meth)acrylate" encompasses both "acrylate" and "methacrylate." The same applies to terms similar to (meth)acrylate; for example, the term "(meth)acryloyl group" encompasses both "acryloyl group" and "methacryloyl group."

[0028] The base resin preferably has, as a structural unit derived from a monomer, one or more structural units selected from a structural unit derived from a compound having a urethane bond and a polymerizable unsaturated bond (hereinafter, sometimes referred to as a "urethane-derived structural unit"), a structural unit derived from a compound having a fluorene skeleton (hereinafter, sometimes referred to as a "fluorene-derived structural unit"), a structural unit derived from a compound having a siloxane bond and a polymerizable unsaturated bond (hereinafter, sometimes referred to as a "siloxane-derived structural unit"), a structural unit derived from a (meth)acrylic acid alkyl ester (hereinafter, sometimes referred to as a "(meth)acrylic acid-derived structural unit"), and a structural unit derived from a reversible addition-fragmentation chain transfer agent (reversible addition fragmentation chain transfer polymerization, sometimes abbreviated herein as a "RAFT agent") (hereinafter, sometimes referred to as a "RAFT agent-derived structural unit").

[0029] The base resin preferably contains, as structural units derived from monomers, one or both of a urethane-derived structural unit and a fluorene-derived structural unit, one or both of a siloxane-derived structural unit and a (meth)acrylic acid-derived structural unit, and a RAFT agent-derived structural unit. The reason for this is that the Young's modulus is 30 N / mm ２ This is because it is easy to obtain a resin substrate 11 having good stretch durability and in which the stretchability is not easily deteriorated even when stretched repeatedly.

[0030] Among the structural units derived from the monomers contained in the substrate resin, the proportions of the urethane-derived structural units, fluorene-derived structural units, siloxane-derived structural units, (meth)acrylic acid-derived structural units, and RAFT agent-derived structural units are not particularly limited, and can be determined appropriately depending on the application of the resin substrate 11 and the required properties such as strength, elongation at break, and stretch durability.

[0031] The greater the number of urethane bonds in the base resin, the lower the Young's modulus and the easier it is to obtain a resin wiring substrate 1 with excellent flexibility. For this reason, the base resin preferably contains urethane-derived structural units. When the base resin contains urethane-derived structural units as structural units derived from monomers, the proportion of urethane-derived structural units among the structural units derived from monomers contained in the base resin is preferably 1% by mass to 80% by mass, and more preferably 5% by mass to 50% by mass. This is because a proportion of urethane-derived structural units of 1% by mass or more can fully achieve the effects of including urethane-derived structural units. Furthermore, a proportion of urethane-derived structural units of 80% by mass or less can sufficiently contain structural units other than urethane-derived structural units, making it easier to obtain a resin base material 11 with good stretch durability that is resistant to deterioration in stretchability even when stretched repeatedly.

[0032] The greater the number of fluorene-derived structural units in the substrate resin, the more likely it is that the resin substrate 11 will have excellent flexibility and good durability. When the substrate resin contains fluorene-derived structural units as structural units derived from monomers, the proportion of fluorene-derived structural units among the structural units derived from monomers contained in the substrate resin is preferably 30% to 99% by mass, and more preferably 35% to 90% by mass. This is because when the proportion of fluorene-derived structural units is 30% by mass or more, the effects of including fluorene-derived structural units can be fully obtained. Furthermore, when the proportion of fluorene-derived structural units is 99% by mass or less, structural units other than fluorene-derived structural units can be sufficiently included, making it easier to obtain a resin substrate 11 with a lower Young's modulus.

[0033] When the base resin has a siloxane-derived structural unit, the resin base material 11 has appropriate water repellency. As a result, the resin base material 11 has excellent durability and is inhibited from deterioration over time due to moisture. Furthermore, when the base resin has a siloxane-derived structural unit, the resin base material 11 has good tackiness (adhesiveness), and the resin wiring board 1 is one in which delamination between the resin base material 11 and the resin coating layer 31 is resistant to delamination.

[0034] When the substrate resin contains a siloxane-derived structural unit as a structural unit derived from a monomer, the proportion of the siloxane-derived structural unit relative to 100 parts by mass of a first oligomer obtained by polymerizing one or more monomers selected from a urethane-derived structural unit, a fluorene-derived structural unit, and a (meth)acrylic acid-derived structural unit by a known method is preferably 0.5 parts by mass to 10 parts by mass, and more preferably 1 part by mass to 5 parts by mass. When the proportion of the siloxane-derived structural unit is 0.5 parts by mass or more, the effect of including the siloxane-derived structural unit is fully obtained. Furthermore, when the proportion of the siloxane-derived structural unit is 10 parts by mass or less, structural units other than the siloxane-derived structural unit can be sufficiently included, making it easier to obtain a resin substrate 11 with properties suited to the application.

[0035] When the base resin has urethane-derived structural units as well as siloxane-derived structural units, the urethane bonds in the resin substrate 11 are less susceptible to hydrolysis, resulting in a resin substrate 11 that is less susceptible to deterioration over time due to hydrolysis, which is preferable. When the base resin has urethane-derived structural units as well as siloxane-derived structural units, the greater the number of siloxane bonds in the resin substrate 11, the less susceptible the urethane bonds in the resin substrate 11 are to hydrolysis, resulting in a resin wiring board 1 with excellent durability. When the base resin has urethane-derived structural units as well as siloxane-derived structural units, the ratio of the number of urethane bonds to the number of siloxane bonds contained in the base resin is not particularly limited and can be determined appropriately depending on the application of the resin wiring board 1 and the required properties such as expansion / contraction durability and elongation at break.

[0036] When the base resin has (meth)acrylic acid-derived structural units, the greater the number of (meth)acrylic acid-derived structural units, the higher the Young's modulus, resulting in a resin base material 11 with good stretch durability and resistance to deterioration in stretchability even when repeatedly stretched. When the base resin contains (meth)acrylic acid-derived structural units as structural units derived from monomers, the proportion of (meth)acrylic acid-derived structural units among the structural units derived from monomers contained in the base resin is preferably 21% to 44% by mass. This is because when the proportion of (meth)acrylic acid-derived structural units is 21% by mass or more, the effect of improving stretch durability due to the inclusion of (meth)acrylic acid-derived structural units can be sufficiently obtained. Furthermore, when the proportion of (meth)acrylic acid-derived structural units is 44% or less, the inclusion of structural units other than (meth)acrylic acid-derived structural units results in a Young's modulus of 30 N / mm ２ This is because the following resin substrate 11 can be easily obtained.

[0037] When the base resin contains a RAFT agent-derived structural unit, variations in the degree of polymerization and crosslinking state are suppressed, resulting in a base resin that is easily dispersed or dissolved in a solvent. When the base resin contains a RAFT agent-derived structural unit as a structural unit derived from a monomer, it is preferably contained in an amount of 0.2 to 5 parts by mass relative to 100 parts by mass of the total monomers contained in the base resin. This is because when the RAFT agent-derived structural unit is contained in an amount of 0.2 parts by mass or more relative to 100 parts by mass of the total monomers contained in the base resin, the effect of containing the RAFT agent-derived structural unit is fully obtained. Furthermore, when the RAFT agent-derived structural unit is contained in an amount of 5 parts by mass or less relative to 100 parts by mass of the total monomers contained in the base resin, structural units other than the RAFT agent-derived structural unit can be sufficiently contained, making it easier to obtain a resin base material 11 with properties suited to the application.

[0038] The substrate resin can be produced, for example, by the method described below. First, a first oligomer is produced by polymerizing one or more monomers selected from a compound having a urethane bond and a polymerizable unsaturated bond, a compound having a fluorene skeleton, and an alkyl (meth)acrylate ester by a known method. A second oligomer is then produced by polymerizing a compound having a siloxane bond and a polymerizable unsaturated bond by a known method. The second oligomer can then be produced by reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) under known conditions using the first oligomer, the second oligomer, a polymerization initiator, and a RAFT agent. This production method is preferred because it facilitates the production of a substrate resin having a skeleton composed of a polymer of the first oligomer and short-chain branches containing structural units derived from the compound having a siloxane bond and a polymerizable unsaturated bond.

[0039] The base resin may be produced by a method of reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) under known conditions using a compound having a urethane bond and a polymerizable unsaturated bond, a compound having a fluorene skeleton, a (meth)acrylic acid alkyl ester, a compound having a siloxane bond and a polymerizable unsaturated bond, a polymerization initiator, and a RAFT agent.

[0040] Examples of compounds having a urethane bond and a polymerizable unsaturated bond that are used as monomers when producing a base resin include known compounds (urethane(meth)acrylates) that have a urethane bond and a (meth)acryloyl group as the group having a polymerizable unsaturated bond. Only one type of compound having a urethane bond and a polymerizable unsaturated bond may be used, or two or more types may be used.

[0041] The compound having a urethane bond and a polymerizable unsaturated bond used in the production of the substrate resin may be an oligomer having a urethane bond and a polymerizable unsaturated bond. Specific examples of oligomers having a urethane bond and a polymerizable unsaturated bond include acrylic urethanes, polyether urethanes, carbonate urethanes, polyester urethanes, and aromatic urethanes. As the oligomer having a urethane bond and a polymerizable unsaturated bond, it is preferable to use an acrylic urethane because this results in a resin substrate 11 with good flexibility. It is more preferable to use an oligomer having a structural unit having a urethane bond and a (meth)acryloyl group, and a structural unit having a urethane bond but no (meth)acryloyl group. It is particularly preferable to use a compound represented by the following formula (1):

[0042]

[0043] As the oligomer having a urethane bond and a polymerizable unsaturated bond, it is also preferable to use an acrylic urethane represented by the following formula (12), since this gives a resin substrate 11 with good flexibility.

[0044] (n in formula (12) １ indicates the degree of polymerization, which is 1 to 40. １１ is a methylene chain having 1 to 10 carbon atoms which may be substituted with an alkyl group having 1 to 4 carbon atoms. １２ is a divalent group derived from a polyol.

[0045] In formula (12), n １ ​represents the degree of polymerization, which is 1 to 40, preferably 10 to 20. In formula (12), R １１ is a methylene chain having 1 to 10 carbon atoms, which may be substituted with an alkyl group having 1 to 4 carbon atoms. １１ is preferably a methylene chain having 1 to 8 carbon atoms which may be substituted with an alkyl group having 1 to 3 carbon atoms. １１ Specific examples of the group include -(CH ２ ) ２ -, -(CH ２ ) ３ -, -(CH ２ ) ４ -, -(CH ２ ) ６ -, -CH ２ CH (CH ２ CH ３ )-(CH ２ ) ４ -, etc. A plurality of R included in formula (12) １１ may all be different, or some or all may be the same, and it is preferable that they are all the same for ease of production. １２ Examples of the divalent group derived from a polyol represented by the formula: ２ ) -, -(CH ２ ) ２ -, -(CH ２ ) ３ -, -(CH ２ ) ４ -, -CH ２ CH (CH ３ ) CH ２ -, -CH ２ CH (CH ２ CH ３ )-(CH ２ ) ４ - and so on. １２ is R １１ It may be the same as or different from.

[0046] The oligomer having a urethane bond and a polymerizable unsaturated bond is an oligomer having acryloyl groups (CH ) at both ends of an acrylic urethane represented by formula (12). ２ =CH ２C(=O)-), one or both of which are methacryloyl groups (CH ２ =CH(CH ２ )C(═O)—) is also preferably used.

[0047] When an acrylic urethane is used as the oligomer having a urethane bond and a polymerizable unsaturated bond, it is preferable to use one having a weight-average molecular weight (Mw) of 5,000 to 180,000, and more preferably one having a weight-average molecular weight (Mw) of 5,000 to 150,000. Furthermore, when an acrylic urethane is used as the oligomer having a urethane bond and a polymerizable unsaturated bond, it is preferable to use one having a number-average molecular weight (Mn) of 3,000 to 150,000, and more preferably one having a number-average molecular weight (Mn) of 3,000 to 120,000, because it can be easily produced. When the weight-average molecular weight (Mw) of the oligomer having a urethane bond and a polymerizable unsaturated bond is 5,000 or more and / or a number-average molecular weight (Mn) of 3,000 or more, a resin substrate 11 with better flexibility is more likely to be obtained. Furthermore, when the weight-average molecular weight (Mw) is 180,000 or less and / or a number-average molecular weight (Mn) is 150,000 or less, gelation of the resin component during polymerization to produce the substrate resin can be prevented.

[0048] As the oligomer having a urethane bond and a polymerizable unsaturated bond, for example, a polyether-based urethane represented by the following formula (13) and / or a polyester-based urethane represented by the following formula (14) may be used.

[0049] (n in formula (13) ２ represents the degree of polymerization, which is 1 to 50. m represents the degree of polymerization, which is 5 to 20. R １３ R is a divalent organic group having 1 to 10 carbon atoms and a polymerizable unsaturated bond. １４ and R １５ are monovalent terminal groups, and may be the same or different from each other. １６ and R １７ are monovalent terminal groups and may be the same or different from one another. １８is a divalent organic group having 1 to 10 carbon atoms and a polymerizable unsaturated bond. １９ are divalent organic groups having 1 to 10 carbon atoms and each having a polymerizable unsaturated bond, and may be the same or different.

[0050] In formula (13), n ２ represents the degree of polymerization, which is from 1 to 50, and preferably from 10 to 40. In formula (13), m represents the degree of polymerization, which is from 5 to 20, and preferably from 10 to 20.

[0051] In formula (13), R １３ R is a divalent organic group having 1 to 10 carbon atoms and a polymerizable unsaturated bond. １３ Preferably, the group having a polymerizable unsaturated bond has a group containing an ethylenically unsaturated bond, and the group having a polymerizable unsaturated bond is an acryloyl group (CH ２ =CH ２ C(=O)-) and / or methacryloyl group (CH ２ =CH(CH ２ )C(=O)-) is preferably a divalent organic group having 1 to 10 carbon atoms. １３ represents a structure derived from an epoxy group, one or more methylene groups (-CH ２ It is preferable that the alkylene group contains any structure or group selected from a methylene chain having a carbonyl group (>C=O) and a carbonate group (-O-(C=O)-O-).

[0052] In formula (13), R １４ and R １５ are monovalent terminal groups and may be the same or different from one another. １４ and R １５ R is preferably a terminal group selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxyl group, an aldehyde group, and an amide group. １４ is preferably —OH or —COOH. １５ is R １３ R １５ If the structure connecting to is not a methylene group, -CH ２OH or -CH ２ It is preferably COOH.

[0053] In formula (14), R １６ and R １７ are monovalent terminal groups and may be the same or different from one another. １６ and R １７ R is preferably a terminal group selected from the group consisting of a hydrogen atom, a hydroxyl group, a carboxyl group, an aldehyde group, and an amide group. １６ and R １７ are -OH, -COOH, and -CH ２ OH, -CH ２ COOH, -C(=O)CH ３ It is preferable that it is any one selected from the following.

[0054] In formula (14), R １８ R is a divalent organic group having 1 to 10 carbon atoms and a polymerizable unsaturated bond. １８ Preferably, the group having a polymerizable unsaturated bond has a group containing an ethylenically unsaturated bond, and the group having a polymerizable unsaturated bond is an acryloyl group (CH ２ =CH ２ C(=O)-) and / or methacryloyl group (CH ２ =CH(CH ２ )C(=O)-) is preferably a divalent organic group having 1 to 10 carbon atoms. １８ represents a structure derived from an epoxy group, one or more methylene groups (-CH ２ It is preferable that the alkylene group contains any structure or group selected from a methylene chain having a carbonyl group (>C=O) and a carbonate group (-O-(C=O)-O-).

[0055] The oligomer having a urethane bond and a polymerizable unsaturated bond may be any of a random copolymer, a block copolymer, and an alternating copolymer, and is preferably a random copolymer because it can be easily produced.

[0056] As a compound having a fluorene skeleton (9,9-bisphenylfluorene skeleton) used as a monomer when producing a base resin, a fluorene compound having a fluorene skeleton and a reactive group such as a hydroxyl group or an amino group can be used. Specific examples of the compound having a fluorene skeleton include bisphenolfluorene (BPF), biscresolfluorene (BCF), bisaminophenylfluorene (BAFL), and bisphenoxyethanolfluorene (BPEF). Only one type of compound having a fluorene skeleton may be used, or two or more types may be used.

[0057] Examples of (meth)acrylic acid alkyl esters used as monomers in producing base resins include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, and decyl (meth)acrylate. One or more types of (meth)acrylic acid alkyl esters may be used. The alkyl methacrylate is preferably methyl (meth)acrylate, since it has good dispersibility with the compound having a urethane bond and a polymerizable unsaturated bond, which is used as a monomer in producing the base resin.

[0058] Examples of compounds having a siloxane bond and a polymerizable unsaturated bond that are used as monomers when producing a resin for a substrate include various known silicone resins having a (meth)acryloyl group as a group having a polymerizable unsaturated bond. Only one type of compound having a siloxane bond and a polymerizable unsaturated bond may be used, or two or more types may be used.

[0059] The compound having a siloxane bond and a polymerizable unsaturated bond may be an oligomer obtained by polymerizing a compound having a siloxane bond and a polymerizable unsaturated bond. Examples of such oligomers include those having a structural unit derived from a modified polydialkylsiloxane in which a (meth)acryloyl group is bonded to one or both ends of a polydialkylsiloxane such as polydimethylsiloxane. The oligomer preferably has a structural unit derived from a modified polydialkylsiloxane in which a (meth)acryloyl group is bonded to one end of the polydialkylsiloxane. This is because a resin substrate 11 can be produced that is made of a substrate resin having short chain branches containing siloxane-derived structural units and that can fully utilize the effects of containing siloxane-derived structural units. As the oligomer obtained by polymerizing a compound having a siloxane bond and a polymerizable unsaturated bond, it is particularly preferable to use a compound represented by the following formula (2) having a structural unit derived from modified polydimethylsiloxane (Silabraine (registered trademark) FM-0721; product name, manufactured by JNC Corporation).

[0060] (In formula (2), n represents the degree of polymerization and is 10 to 150. Me represents —CH ３ n-Bu is —CH ２ CH ２ CH ２ CH ３ It is.)

[0061] As the RAFT agent, it is preferable to use, for example, one having one or more groups represented by the following general formula (11), (21) or (31).

[0062] (In formula (11), Z １ is an alkyl group, and one or more hydrogen atoms in the alkyl group may be substituted with a cyano group, a carboxy group, a methoxycarbonyl group, or an aryl group, and the two or more substituents may be the same or different. ２ is an alkyl group, and Z ３ is an aryl group. ４is a hydrogen atom or a halogen atom. * in formula (11), (21), or (31) indicates a bond to which the group represented by formula (11), (21), or (31) is bonded.

[0063] As the polymerization initiator used in producing the base resin, for example, one or more known initiators such as persulfates, hydrogen peroxide, azo compounds, and organic peroxides can be used, and it is preferable to use an azo compound such as dimethyl-2,2'-azobis(2-methylpropionate).

[0064] In the above-described method for producing a base resin, the first oligomer and the second oligomer are RAFT polymerized using a RAFT agent, thereby forming a crosslinked structure during polymerization, thereby preventing gelation of the resin components. Furthermore, in the above-described method, the first oligomer and the second oligomer are RAFT polymerized, making it possible to easily produce a base resin having a desired degree of polymerization and crosslinked state.

[0065] Furthermore, when the base resin does not contain a siloxane-derived structural unit, the base resin can be produced, for example, by the method described below. That is, the base resin can be produced by a method in which one or more monomers selected from a compound having a urethane bond and a polymerizable unsaturated bond, a compound having a fluorene skeleton, and a (meth)acrylic acid alkyl ester are subjected to reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) using a polymerization initiator and a RAFT agent under known conditions. In this case, since one or more monomers are RAFT polymerized using a RAFT agent, a crosslinked structure is formed during polymerization, thereby preventing gelation of the resin components. Furthermore, since the above-mentioned production method involves RAFT polymerization of one or more monomers, a base resin having a desired degree of polymerization and crosslinked state can be easily produced.

[0066] "Filler" Examples of fillers that may be contained in the resin substrate 11 as needed include carbon black, silica, calcium carbonate, talc, and clay. Only one type of filler may be used, or two or more types may be used. The type and shape, such as particle size, of the filler are not particularly limited, and can be appropriately determined depending on the application of the resin substrate 11 and the required properties, such as strength, elongation at break, and stretch durability.

[0067] When the resin substrate 11 contains a filler, the content of the filler in the resin substrate 11 is, for example, preferably 5 to 30 parts by mass, and more preferably 10 to 20 parts by mass, per 100 parts by mass of the base resin. When the content of the filler in the resin substrate 11 is 5 parts by mass or more per 100 parts by mass of the base resin, the effect of improving the stretch durability due to the inclusion of the filler is sufficiently obtained. Furthermore, when the content of the filler in the resin substrate 11 is 30 parts by mass or less per 100 parts by mass of the base resin, it is possible to prevent the flexibility of the resin substrate 11 from being impaired due to an excessive filler content.

[0068] The resin substrate 11 is preferably a solidified resin composition containing a substrate resin, an optional filler, and a solvent. The solvent contained in the resin composition may be any solvent capable of dispersing or dissolving the substrate resin. Specifically, examples of solvents that can be used include N,N-dimethylacetamide (DMAc), methyl ethyl ketone (MEK), N,N-dimethylformamide (DMF), diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, butyl carbitol (BC), butyl carbitol acetate (BCA), ethyl cyanoacrylate (ECA), α-terpineol, acetone, ethanol, methanol, ethyl lactate, butyl lactate, toluene, isopropyl alcohol, isobutyl alcohol, ethyl acetate, and butyl acetate. The solvent may be one selected from the above solvents, or two or more may be used. As the solvent, it is preferable to use methyl ethyl ketone (MEK) and / or butyl carbitol acetate (BCA) since the base resin is easily dispersed or dissolved in these solvents.

[0069] The resin substrate 11 preferably has a breaking elongation rate of 50% or more, and more preferably 100% or more. When the resin substrate 11 has a breaking elongation rate of 50% or more, the resin wiring board 1 can be suitably used in various stretchable devices such as wearable devices. The breaking elongation rate of the resin substrate 11 can be changed by appropriately selecting the material of the resin substrate 11 and the amount used. In addition, the breaking elongation rate of the resin substrate 11 is preferably 3000% or less. This is because it is easy to obtain a resin substrate 11 with good stretching durability, in which stretching is resistant to deterioration even when stretched repeatedly.

[0070] In this specification, "elongation at break" is defined as {(length at break - length before pulling) / length before pulling} x 100 (%). The elongation at break can be measured in each predetermined direction. In this specification, for example, "the elongation at break of the resin substrate 11 is 50% or more" specifies that the elongation at break in the direction in which the elongation at break is greatest is 50% or more. If there is no anisotropy in the elongation at break, the elongation at break will be the same in all directions. Furthermore, if the anisotropy of the elongation at break is small, the elongation at break will be close in all directions.

[0071] (Wiring Pattern 21) The wiring pattern 21 is composed of electrically connected linear wiring 22 and stretchable wiring 24. The wiring pattern 21 is linear and has a uniform width in a plan view. The planar shape of the wiring pattern 21 is not particularly limited and can be determined appropriately depending on the application of the resin wiring board 1, etc. The planar shape of the wiring pattern 21 is preferably a shape that is unlikely to break or peel even if the resin base material 11 is deformed, and can be, for example, a curved shape in which successive arcs having a predetermined radius of curvature are connected, as shown in FIG. 1 . The number of wiring patterns 21 can be determined appropriately depending on the application of the resin wiring board 1, etc.

[0072] 1, 2(a), and 2(b), the linear wiring 22 is arranged, in plan view, at both ends of the strip-shaped resin substrate 11. The inner ends of the linear wiring 22 arranged at both ends are electrically connected to the outer ends 24a of the elastic wiring 24, respectively.

[0073] The linear wiring 22 is made of a conductive material and has a substantially rectangular cross-sectional shape. The linear wiring 22 has a planar line shape as shown in Fig. 1, and a portion of the linear wiring 22 in plan view is covered by the resin base material 11 and the resin coating layer 31 in cross-section as shown in Fig. 2(a). The linear wiring 22 also has an embedded portion 22a and an exposed portion 22b as shown in Figs. 2(a) and 2(b).

[0074] In a cross-sectional view, the embedded portion 22a is formed along the inside of the recess 11b formed in the first surface 11a of the resin base material 11. Therefore, the outer surface of the embedded portion 22a is disposed in contact with the resin base material 11. Furthermore, the embedded portion 22a is embedded in the recess 11b of the resin base material 11, thereby holding the linear wiring 22.

[0075] The exposed portions 22 b are exposed from the first surface 11 a of the resin substrate 11. In this embodiment, as shown in FIG. 2B , the linear wiring 22 arranged at both ends of the resin substrate 11 has the exposed portions 22 b. Therefore, for example, by forming wiring electrically connected to another device in contact with the exposed portions 22 b, the electrical connection to the other device can be easily achieved. Specifically, for example, by using a plating method, a method of applying a conductive material using an inkjet printer or a dispenser, the electrical connection to the other device can be easily achieved by forming wiring electrically connected to the other device in contact with the exposed portions 22 b exposed from the first surface 11 a of the resin substrate 11.

[0076] Furthermore, the exposed portion 22b can function as a pad when electrically connecting the linear wiring 22 and the stretchable wiring 24 using a known method. In the present embodiment, the exposed portion 22b is formed on approximately the same plane as the first surface 11a of the resin substrate 11. Therefore, the linear wiring 22 and the stretchable wiring 24 can be easily electrically connected compared to, for example, a case where the exposed portion 22b is formed protruding from the first surface 11a of the resin substrate 11, or a case where the exposed portion 22b is formed at a position closer to the bottom surface of the recess 11b than the first surface 11a of the resin substrate 11. In other words, when the exposed portion 22b is formed on approximately the same plane as the first surface 11a of the resin substrate 11, it can be more preferably used as a pad.

[0077] In this embodiment, as shown in FIGS. 2( a) and 2(b), the exposed portion 22b is formed substantially flush with the first surface 11a of the resin substrate 11. Therefore, compared to a case where the exposed portion 22b is formed, for example, so as to protrude from the first surface 11a of the resin substrate 11, the proportion of the outer surface area of ​​the embedded portion 22a is relatively large. As a result, the contact area between the linear wiring 22 and the resin substrate 11 is large, and the adhesion of the linear wiring 22 to the resin substrate 11 is improved. Moreover, because the exposed portion 22b is formed substantially flush with the first surface 11a of the resin substrate 11, the entire linear wiring 22 is embedded in the recess 11b in a cross-sectional view, and the linear wiring 22 is more effectively held by the recess 11b. Therefore, the linear wiring 22 is even less likely to peel off from the resin substrate 11 even when the resin substrate 11 expands or contracts.

[0078] Furthermore, since the exposed portion 22b is formed on approximately the same plane as the first surface 11a of the resin base material 11, the linear wiring 22 having the buried portion 22a and the exposed portion 22b can be easily manufactured using the manufacturing method described later, and productivity is superior compared to, for example, a case where the exposed portion 22b is formed protruding from the first surface 11a of the resin base material 11, or a case where the exposed portion 22b is formed at a position closer to the bottom surface of the recess 11b than the first surface 11a of the resin base material 11.

[0079] In this embodiment, the linear wiring 22 is preferably made of a metal, and more preferably made of a metal film having a particle diameter of 0.5 μm to 2.0 μm. When the linear wiring 22 is made of a metal, the linear wiring 22 can be easily manufactured using a plating method described below. Furthermore, when the linear wiring 22 is made of a metal film having a particle diameter of 0.5 μm to 2.0 μm, the linear wiring 22 can be formed to have a sufficient thickness using a plating method described below.

[0080] The particle diameter of the metal film forming the linear wiring 22 can be measured, for example, by the following method: observing the surface of the metal film using a scanning electron microscope (SEM) (for example, a 10,000x magnification field of view), measuring the particle diameters of 100 particles within the field of view, and calculating the average value.

[0081] Furthermore, the linear wiring 22 is preferably made of a metal film having a crystal grain size of 0.3 μm to 1.8 μm, and more preferably made of a metal film having a crystal grain size of 0.7 μm to 1.5 μm, because the linear wiring 22 can be easily formed using a plating method described later.

[0082] The crystal grain size of the metal film forming the linear wiring 22 can be measured, for example, by the following method: The surface of the metal film is observed using a transmission electron microscope (TEM) (for example, a 10,000x magnification field), the crystal grain size of 100 particles within the field is measured, and the average value is calculated.

[0083] In the present embodiment, the linear wiring 22 being "made of a metal" means that the linear wiring 22 contains a metal component of 90% by mass or more. For example, when the metal is copper, the linear wiring 22 is a wiring made of copper with a purity of 90% by mass or more, and may be a wiring made of copper with a purity of 96% by mass or more, or may be a wiring made of copper with a purity of 97% by mass or more.

[0084] The linear wiring 22 is preferably made of a conductive material with a heat resistance temperature of 220° C. or higher, and more preferably made of a conductive material with a heat resistance temperature of 500° C. or higher. Examples of conductive materials with a heat resistance temperature of 220° C. or higher include copper (heat resistance temperature 1085° C.), silver (heat resistance temperature 962° C.), gold (heat resistance temperature 1064° C.), palladium (heat resistance temperature 1555° C.), tin (heat resistance temperature 232° C.), and nickel (heat resistance temperature 1453° C.). The linear wiring 22 is preferably made of copper because it can be easily manufactured using the plating method described below, has a high heat resistance temperature, and is excellent in conductivity.

[0085] In this specification, the term "heat resistant temperature" means a temperature at which discoloration of a conductive material or a change in shape of a conductive material is observed when heated.

[0086] If the heat resistance temperature of the linear wiring 22 is 220°C or higher, there are more options for forming an electrical connection between wiring electrically connected to another device and the exposed portion 22b of the linear wiring 22, for example, in order to electrically connect the resin wiring board 1 to another device.

[0087] Specifically, when the heat resistance temperature of the linear wiring 22 is 220° C. or higher, methods for forming an electrical connection between wiring electrically connected to another device and the exposed portion 22 b of the linear wiring 22 include a spot soldering mounting method using a molten low-melting point metal, and a bonding method using an adhesive such as a conductive adhesive or an anisotropic adhesive. Among these, the spot soldering mounting method is preferred because it can easily and firmly electrically connect the exposed portion 22 b of the linear wiring 22 of the resin wiring board 1 to the wiring electrically connected to another device.

[0088] [Stretchable Wiring 24] As shown in Figures 1 and 2(b), the stretchable wiring 24 is a linear wiring having stretchability and arranged on the first surface 11a of the resin substrate 11. The stretchable wiring 24 has a substantially rectangular cross-sectional shape. As shown in Figures 1 and 2(b), one end 24a of the stretchable wiring 24 is formed in contact with the exposed portion 22b of the linear wiring 22. As a result, the stretchable wiring 24 is electrically connected to the linear wiring 22.

[0089] The stretchable wiring 24 can be one containing metal powder and a known stretchable resin. The metal powder contained in the stretchable wiring 24 is not particularly limited, and known materials can be used. The metal powder preferably contains scale-shaped (flake-shaped) powder. When the metal powder contains scale-shaped powder, the scale-shaped powder has upper and lower surfaces that extend in the planar direction, which increases the proportion of surface contact between the metal powder particles, resulting in high conductivity (low resistivity).

[0090] In this specification, "scale-shaped powder" refers to powder (metal powder) whose thickness is 1 / 10 or less of the maximum particle diameter. The maximum particle diameter of scale-shaped powder is determined as follows. The length from end to end of each scale-shaped powder varies depending on the direction in a plan view, and the longest of these lengths is defined as the maximum particle diameter. The maximum particle diameter can be determined by methods such as observation with an optical microscope or scanning electron microscope (SEM) (for example, a 5000x field of view).

[0091] Examples of the metal powder contained in the elastic wiring 24 include silver (Ag) powder, carbon (C) powder, copper (Cu) powder, palladium (Pd) powder, gold (Au) powder, platinum (Pt) powder, etc. Among these, it is preferable to use silver powder or an alloy powder mainly composed of silver as the metal powder, since this results in an elastic wiring 24 with low resistance and excellent conductivity.

[0092] In this specification, "alloy powder containing silver as a main component" means an alloy powder containing more than 50 wt% of silver. The alloy powder containing silver as a main component preferably contains 70 wt% or more of silver, more preferably 80 wt% or more of silver, and even more preferably 90 wt% or more of silver. The silver powder may also be silver powder whose surface is silver and whose interior is made of a metal other than silver, such as silver-coated copper powder.

[0093] The metal powder may be prepared as needed or commercially available. Examples of methods for producing particulate silver powder include adding a reducing agent-containing aqueous solution to an aqueous reaction system containing silver ions to reduce and precipitate silver particles. Furthermore, flake-shaped metal powder can be produced, for example, by forming a thin film of the desired metal and then pulverizing the thin film. Since the flake-shaped powder produced by this method is obtained by pulverizing the thin film, the individual crushed metal flakes are also flat. The thickness (i.e., the degree of flatness) relative to the maximum particle diameter of the flake-shaped powder can be adjusted by adjusting the thickness of the thin film used as the material and the degree of pulverization.

[0094] The stretchable resin contained in the stretchable wiring 24 can be the same as the base resin that forms the resin substrate 11. The stretchable resin contained in the stretchable wiring 24 and the base resin that forms the resin substrate 11 may be the same or different, and are preferably the same. This is because the stretchable wiring 24 is likely to have good adhesion to the resin substrate 11.

[0095] The content of the stretchable resin contained in the stretchable wiring 24 is preferably in the range of 8% by mass to 20% by mass, and more preferably in the range of 10% by mass to 18% by mass. When the content of the stretchable resin contained in the stretchable wiring 24 is 8% by mass or more, the stretchable wiring 24 has good stretchability and excellent adhesion to the resin substrate 11. When the content of the stretchable resin contained in the stretchable wiring 24 is 20% by mass or less, it is easy to ensure the content of metal powder in the stretchable wiring 24, and therefore it is easy to obtain a stretchable wiring 24 with high conductivity, which is preferable.

[0096] 1, 2(a), and 2(b), the resin wiring board 1 of this embodiment has a resin coating layer 31 that covers the stretchable wiring 24 arranged on the first surface 11a of the resin base material 11 and also covers the exposed portions 22b of the linear wiring 22. The resin coating layer 31 is preferably stretchable because it tends to have good adhesion to the resin base material 11.

[0097] The resin coating layer 31 may be made of a known material, preferably containing a stretchable resin, such as polyimide resin, polyamide resin, epoxy resin, polycarbonate, silicone resin, polyacrylic resin, or fluororesin.

[0098] The elastic resin contained in the resin coating layer 31 can be the same as the substrate resin that forms the resin substrate 11. The elastic resin contained in the resin coating layer 31 and the substrate resin that forms the resin substrate 11 may be the same or different. When the elastic resin contained in the resin coating layer 31 and the substrate resin that forms the resin substrate 11 are the same, this is preferable because the resin coating layer 31 is likely to have good adhesion to the resin substrate 11.

[0099] (Electronic component 41) In the stretchable device of this embodiment, two electronic components 41 are arranged on the first surface 11a of the resin base material 11 of the resin wiring board 1. These electronic components 41 are each electrically connected to the stretchable wiring 24 shown in Figures 1 and 2(b). The number and type of electronic components 41 are not particularly limited and are determined appropriately depending on the application of the stretchable device.

[0100] Known electronic components can be used as the electronic component 41. Examples of the electronic component 41 include various sensors, capacitors, inductors, high-frequency filters, transformers, resistors, varistors, diodes, various ICs, various actuators, antennas, and batteries. When the electronic component 41 is a battery, examples include a solar cell, a lithium-ion battery, and an electric double-layer capacitor. Examples of the solar cell include a double-sided electrode solar cell and a back-side electrode solar cell in terms of electrode arrangement. Furthermore, examples of the solar cell include inorganic material solar cells such as silicon-based solar cells and compound semiconductor-based solar cells, and organic solar cells in terms of materials.

[0101] [Method for manufacturing a stretchable device] Next, an example of a method for manufacturing a stretchable device shown in Figures 1, 2(a), and 2(b) will be described in detail with reference to the drawings. (Formation of wiring 25 that becomes linear wiring 22) In this embodiment, first, a resin substrate 11 having linear wiring 22 is manufactured. Figures 3(a) to 3(h) are process diagrams for explaining an example of a method for manufacturing the stretchable device shown in Figure 1. Figures 3(a) to 3(h) are cross-sectional schematic views showing enlarged regions corresponding to part of a cross section in a direction perpendicular to the longitudinal direction of the resin substrate 11 shown in Figure 1.

[0102] First, as shown in Fig. 3(a), a plate-shaped manufacturing substrate 5 is prepared. A known substrate, such as a resin substrate made of a resin such as polytetrafluoroethylene (PTFE), can be used as the manufacturing substrate 5. Next, as shown in Fig. 3(b), a plating seed layer 6 made of a copper thin film or the like is provided on the manufacturing substrate 5 by a sputtering method, a CVD method, or the like.

[0103] Next, a photosensitive resist layer 7 is formed on the plating seed layer 6 using a known method. Thereafter, the photosensitive resist layer 7 is patterned into a shape corresponding to the planar shape of the linear wiring 22 using photolithography, thereby exposing a portion of the plating seed layer 6 as shown in Fig. 3(c). Next, as shown in Fig. 3(d), wiring 25 made of copper or the like that will become the linear wiring 22 (see Figs. 1, 2(a) and 2(b)) is formed on the exposed plating seed layer 6 by plating.

[0104] Next, as shown in Fig. 3(e), the photosensitive resist layer 7 is peeled off by a known method to expose the plating seed layer 6. Thereafter, as shown in Fig. 3(f), the exposed plating seed layer 6 is removed by a known method such as etching.

[0105] (Formation of resin substrate 11) First, a resin composition containing the above-mentioned substrate resin, a filler optionally contained, and a solvent is prepared using a known method. Next, as shown in FIG. 3(g), the resin composition is applied to a manufacturing substrate 5 having wiring 25 in a predetermined planar shape and thickness to form a resin composition layer 12 having a strip-like shape corresponding to the planar shape of the resin substrate 11 (coating process). In the coating process, a known method can be used as a method for applying the resin composition. Specifically, as the coating method, for example, a method using various coaters or wire bars, various printing methods including inkjet printing, etc. can be used.

[0106] Next, the resin composition layer 12 is dried and solidified (drying and solidification step). This results in a sheet-like resin substrate 11. In the drying and solidification step, the drying temperature for drying the resin composition layer 12 is, for example, preferably 25°C or higher and 150°C or lower, and more preferably 25°C or higher and 120°C or lower. When the drying temperature is 25°C or higher, the resin composition layer 12 can be dried more efficiently, and the sheet-like resin substrate 11 can be efficiently produced. When the drying temperature is 150°C or lower, deterioration of the sheet-like resin substrate 11 due to an excessively high drying temperature can be suppressed.

[0107] In the drying and solidification process, completion of solidification by drying the resin composition layer 12 (completion of the sheet-shaped resin substrate 11) can be confirmed, for example, by the fact that no clear change is observed in the mass of the resin composition layer 12 being dried.

[0108] Next, in this embodiment, the sheet-like resin base material 11 and the wiring 25 are peeled off in an integrated state from on the manufacturing substrate 5. As a result, as shown in Fig. 3(h) , linear wiring 22 is formed, which has an embedded portion 22a formed so as to be embedded along the recess 11b formed in the first surface 11a of the resin base material 11 in a cross-sectional view, and an exposed portion 22b exposed from the first surface 11a of the resin base material 11.

[0109] (Formation of stretchable wiring 24) Next, in this embodiment, a stretchable electrical wiring paste containing a predetermined amount of the above-mentioned base resin, a solvent, and a metal powder such as silver powder is used to form the stretchable wiring 24 on the resin base material 11 having the linear wiring 22. As the stretchable electrical wiring paste, it is preferable to use one that contains 50% by mass to 90% by mass of metal powder relative to the content of resin in the stretchable electrical wiring paste, for example.

[0110] First, the stretchable electrical wiring paste is applied to the resin substrate 11 having the linear wiring 22 in a shape corresponding to the planar shape of the stretchable wiring 24, to form a wiring paste layer of a predetermined thickness (application step). In the application step, a known method can be used to apply the stretchable electrical wiring paste. Specifically, as the application method, for example, a method using various coaters or a wire bar, or various printing methods including inkjet printing can be used.

[0111] 3(h), the surface of the exposed portion 22b of the linear wiring 22 is formed on approximately the same plane as the first surface 11a of the resin base material 11. Therefore, by applying the stretchable electrical wiring paste in a predetermined shape to the resin base material 11 having the linear wiring 22, the stretchable electrical wiring paste can also be easily applied to the region on the surface of the exposed portion 22b of the linear wiring 22 that is electrically connected to the stretchable wiring 24.

[0112] Next, the wiring paste layer is dried and solidified (drying and solidifying step). This allows the elastic wiring 24 to be obtained. In the drying and solidifying step, the drying temperature for drying the wiring paste layer is, for example, preferably 25°C or higher and 150°C or lower, and more preferably 25°C or higher and 120°C or lower. When the drying temperature is 25°C or higher, the wiring paste layer can be dried more efficiently, and the elastic wiring 24 can be produced efficiently. When the drying temperature is 150°C or lower, it is possible to prevent the resin substrate 11 and the elastic wiring 24 from being altered in quality due to an excessively high drying temperature.

[0113] In the drying and solidifying step, completion of solidification by drying the wiring paste layer (completion of the stretchable wiring 24) can be confirmed, for example, by the fact that no clear change is observed in the mass of the wiring paste layer being dried (the total mass of the resin substrate 11, the linear wiring 22, and the wiring paste layer). Through the above steps, a stretchable linear stretchable wiring 24 is formed, which is disposed on the first surface 11a of the resin substrate 11 and has one end 24a in contact with the exposed portion 22b of the linear wiring 22.

[0114] (Formation of resin coating layer 31) Next, in this embodiment, a resin composition containing the above-mentioned base resin and a solvent is used to form an elastic resin coating layer 31 on the first surface 11a of the resin base material 11 having the linear wiring 22 and the elastic wiring 24.

[0115] First, a resin composition containing the above-mentioned substrate resin and solvent is applied to the first surface 11a of the resin substrate 11 having the linear wiring 22 and the stretchable wiring 24 in a shape corresponding to the planar shape of the resin coating layer 31 to form a resin composition layer of a predetermined thickness (application step). In the application step, the resin composition can be applied by the same method as that which can be used when forming the resin substrate 11.

[0116] Next, the resin composition layer is dried and solidified (drying and solidifying step) in the same manner as when the resin substrate 11 is formed. This forms a resin coating layer 31 that covers the elastic wiring 24. In the drying and solidifying step, the drying temperature for drying the resin composition layer is, for example, preferably 25°C or higher and 150°C or lower, and more preferably 25°C or higher and 120°C or lower, as in the case of forming the resin substrate 11. When the drying temperature is 25°C or higher, the resin composition layer can be dried more efficiently, and the resin coating layer 31 can be produced efficiently. When the drying temperature is 150°C or lower, it is possible to prevent the resin substrate 11 having the elastic wiring 24 and the resin coating layer 31 from deteriorating due to an excessively high drying temperature.

[0117] In the drying and solidification process, completion of solidification by drying the resin composition layer (completion of the resin coating layer 31) can be confirmed, for example, by the fact that no clear change is observed in the mass of the resin composition layer being dried (the total mass of the resin substrate 11, linear wiring 22, stretchable wiring 24, and resin composition layer).

[0118] (Mounting of electronic component 41) Next, in this embodiment, the electronic component 41 is placed at a predetermined position on the first surface 11a of the resin substrate 11 having the resin coating layer 31, the linear wiring 22, and the stretchable wiring 24 by a known method such as a method using a surface mounter. Then, the electronic component 41 and the stretchable wiring 24 are electrically connected by a known method using molten solder, a conductive adhesive, an anisotropic adhesive, or the like. By performing the above steps, the stretchable device of this embodiment can be obtained.

[0119] [Other Examples] The above describes the embodiments of the present invention in detail, but each configuration and combination thereof in each embodiment is merely an example, and additions, omissions, substitutions, and other modifications of the configurations are possible within the scope that does not deviate from the spirit of the present invention.

[0120] For example, in the above-described stretchable device, as shown in FIGS. 1, 2(a), and 2(b), a case has been described as an example in which the surface of the electronic component 41 opposite the resin substrate 11 and the portion of the stretchable wiring 24 electrically connected to the electronic component 41 that is not covered by the resin coating layer 31 are exposed, but the electronic component 41 and the stretchable wiring 24 may be covered by a resin coating layer.

[0121] The resin coating layer that coats the electronic components 41 and the stretchable wiring 24 can be made of a known material, and preferably contains a stretchable resin. The stretchable resin contained in the resin coating layer that coats the electronic components 41 and the stretchable wiring 24 can be the same as the base resin that forms the resin substrate 11. The stretchable resin contained in the resin coating layer that coats the electronic components 41 and the stretchable wiring 24 may be the same as or different from the resin that forms the resin substrate 11 and / or the resin coating layer 31, and is preferably the same.

[0122] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the following examples. [Resin Compositions 1 to 26] A siloxane shown in Table 1 was mixed with a monomer mixture obtained by mixing urethane, fluorene, and methacrylic acid in the ratios shown in Table 1, in the ratios shown in Table 1 (parts by mass relative to 100 parts by mass of the mixed monomer). The mixture was heated in methyl ethyl ketone (MEK) to undergo reversible addition-fragmentation chain transfer polymerization (RAFT polymerization) using 1.0 part by mass of dimethyl-2,2'-azobis(2-methylpropionate) (V601; product name, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) as a polymerization initiator relative to 100 parts by mass of the total monomers, and 1.5 parts by mass of a RAFT agent (S,S-dibenzyltrithiocarbonate; manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) relative to 100 parts by mass of the total monomers, to obtain a resin.

[0123] The obtained resin was mixed with the filler shown in Table 1 in the ratio (parts by mass relative to 100 parts by mass of resin) shown in Table 1, and dispersed in MEK as a solvent to prepare Resin Compositions 1 to 26, each having a resin content of 70% by mass to 100% by mass.

[0124]

[0125] The urethane, fluorene, methacrylic acid, siloxane, and fillers A, B, C, and D shown in Table 1 are as follows: [Urethane (resin compositions 1 to 9, 11 to 24)] A random copolymer represented by formula (1) (weight average molecular weight (Mw) 61,000, number average molecular weight (Mn) 30,800). [Urethane (resin compositions 25, 26)] A random copolymer represented by formula (12) (n in formula (12) １ is 20. R １１ is -(CH ２ ) ６ - is. R １２ is -(CH ２ )-. The weight average molecular weight (Mw) is 5,200 and the number average molecular weight (Mn) is 4,110.

[0126] [Fluorene] GA-2800 (trade name; manufactured by Osaka Gas Chemicals Co., Ltd.). [Methacrylic acid] Methyl methacrylate (manufactured by Kuraray Co., Ltd.). [Siloxane] A compound represented by formula (2) having a structural unit derived from modified polydimethylsiloxane (Silabraine (registered trademark) FM-0721; trade name; manufactured by JNC Corporation). [A] Silica, average particle size 2.1 μm to 2.6 μm (manufactured by Tosoh Silica Corporation). [B] Silica, average particle size 1.5 μm to 1.9 μm (manufactured by Tosoh Silica Corporation). [C] Calcium carbonate, average particle size: 0.7 μm (manufactured by Shiraishi Calcium Co., Ltd.). [D] Silica, average particle size: 2.5 μm to 3.5 μm (manufactured by Tosoh Silica Corporation).

[0127] Resin compositions 1 to 26 thus obtained were used to form resin substrates 1 to 26 by the following method. Resin compositions 1 to 26 were each applied to a manufacturing substrate made of a PET film using a coater, and then dried at 80°C to solidify, thereby obtaining resin substrates 1 to 26 in the form of sheets having a thickness of 0.05 mm.

[0128] The resin substrates 1 to 26 thus obtained were peeled from the manufacturing substrate, and the Young's modulus, elongation at break, strength, and stretch durability of each were examined using the methods described below. The results are shown in Table 2. In the methods described below, the Young's modulus, elongation at break, strength, and stretch durability of the resin substrate were measured at a measurement point of 10 mm width and 10 mm length, but the measurement results of the Young's modulus, elongation at break, strength, and stretch durability of the resin substrate were similar regardless of the dimensions of the measurement point. Therefore, the dimensions of the measurement point for the above items of the resin substrate may be, for example, 5 mm width and 5 mm length, or 3 mm width and 3 mm length.

[0129] [Measurement of Young's Modulus] Five strip-shaped measurement samples, each 10 mm wide and 35 mm long, were cut out from the resin substrate. A metal substrate was clamped between the upper and lower grips of the measuring instrument, and the measurement sample was fixed to the metal substrate with double-sided tape so that the measurement point was 10 mm wide and 10 mm long. Thereafter, the tensile stress and strain of the measurement sample were measured using a tensile tester (product name: Autograph AGS-5kNX, manufactured by Shimadzu Corporation). Using the results, a stress-strain diagram was created, and the Young's modulus of the measurement sample was calculated from the slope of the proportional limit. The average value of the Young's moduli of the five measurement samples was taken as the Young's modulus of each resin substrate.

[0130] [Strength Measurement] Five strip-shaped measurement samples, each 10 mm wide and 35 mm long, were cut out from the resin substrate. The maximum tensile strength of each measurement sample was calculated using the method described below, and the average value was used as the strength. A metal substrate was clamped between the upper and lower grips of the measuring device, and the measurement sample was fixed to the metal substrate with double-sided tape so that the measurement point was 10 mm wide and 10 mm long. The measurement sample was then pulled at a pulling rate of 10 mm / min using a tensile tester (product name: Autograph AGS-5kNX, manufactured by Shimadzu Corporation). The maximum tensile strength of the measurement sample was then measured.

[0131] [Measurement of Breaking Elongation] Six strip-shaped measurement samples, each 10 mm wide and 30 mm long, were cut out from each resin substrate. The elongation at break of each measurement sample was calculated by the method described below.

[0132] The metal substrate was clamped between the upper and lower grips of the measuring instrument, and the measurement sample was fixed to the metal substrate with double-sided tape so that the measurement point was 10 mm wide and 10 mm long. The measurement sample was then pulled at a pulling rate of 10 mm / min using a tensile tester (product name: Autograph AGS-5kNX, manufactured by Shimadzu Corporation). The length of the measurement sample at break was measured, and the length before pulling (10 mm) was subtracted from that length to calculate the elongation at break (length at break - length before pulling) for each measurement sample. The average value was taken as the elongation at break, and the elongation at break was calculated using the following formula: Elongation at break (%) = {elongation at break / length before pulling} × 100

[0133] [Stretching Durability] In the same manner as in the measurement of breaking elongation percentage, a strip-shaped measurement sample having a width of 10 mm and a length of 30 mm was cut out from the resin substrate, and the stretching durability was calculated by the method described below.

[0134] The metal substrate was clamped between the upper and lower grips of the measuring instrument, and the measurement sample was fixed to the metal substrate with double-sided tape so that the measurement point was 10 mm wide and 10 mm long. The measurement sample was then pulled at a tensile speed of 10 mm / min using a tensile tester (product name: Autograph AGS-5kNX, manufactured by Shimadzu Corporation) to measure the change in stretch strength when stretched to 2 mm (20% of the length of the measurement point). The change in stretch strength when the measurement sample was returned to its original length at a tensile speed of 10 mm / min was then measured. From these measurement results, the peak strength (maximum value) of the first stretch strength when the measurement sample was stretched and returned was determined.

[0135] Thereafter, the peak strengths of the stretching strengths at the second to 100th times were determined in the same manner as the peak strength of the stretching strength at the first time. Then, the ratio of the peak strength of the stretching strength at the first time to the peak strength of the stretching strength at the 100th time (peak strength of the stretching strength at the 100th time / peak strength of the stretching strength at the first time) was calculated to evaluate the stretching durability.

[0136]

[0137] As shown in Tables 1 and 2, by using resin compositions 1 to 18 and 20 to 26, the Young's modulus was 30 N / mm ２ It was confirmed that low-strength resin substrates 1 to 18 and 20 to 26, as shown below, could be obtained. Furthermore, as shown in resin substrates 17 and 19, when [urethane], [siloxane], and [methacrylic acid] were used as monomers, it was found that by reducing the proportion of [urethane] and increasing the proportion of "methacrylic acid," the Young's modulus increased and the stretch durability tended to improve. Furthermore, as shown in resin substrates 16 and 20 to 24, when [urethane] and [siloxane] were used as monomers, it was confirmed that the inclusion of a filler improved the stretch durability.

[0138] The resin substrate 8 and the resin substrate 18 were analyzed by photothermal infrared spectroscopy (O-PTIR) using an infrared spectrometer (trade name: mIRage, manufactured by Japan Thermal Consulting Co., Ltd.). The results are shown in FIG.

[0139] Fig. 4 shows infrared absorption (IR) spectra of resin substrate 8 and resin substrate 18. The dotted line in Fig. 4 shows the results for resin substrate 18, and the solid line shows the results for resin substrate 18.

[0140] The wavelength of the IR spectrum shown in FIG. －１ ±35cm －１ , wavelength 1500cm －１ ±35cm －１ , wavelength 1600cm －１ ±35cm －１ The peak at a wavelength of 1150 cm in the IR spectrum is due to fluorene. －１ ±35cm －１ The peak at a wavelength of 1260 cm in the IR spectrum is due to methacrylic acid. －１ ±35cm －１ , wavelength 1741cm －１ ±25cm －１ The peak is due to C═O.

[0141] 1...resin wiring board, 11...resin base material, 11a...first surface, 12...resin composition layer, 21...wiring pattern, 22...linear wiring, 22a...embedded portion, 22b...exposed portion, 24...elastic wiring, 25...wiring, 31...resin coating layer.

Claims

1. Young's modulus is 30N / mm ２ A resin wiring board comprising: a resin base material having a wiring pattern formed on the resin base material; 2. The resin wiring board according to claim 1, wherein the resin component contained in the resin base material contains a structural unit derived from a compound having a fluorene skeleton.

3. The resin wiring board according to claim 2, wherein the proportion of structural units derived from a compound having a fluorene skeleton among structural units derived from monomers contained in the resin component contained in the resin base material is 30 mass % or more.

4. The resin wiring board according to claim 1, wherein the resin component contained in the resin base material contains a structural unit derived from a compound having a urethane bond and a polymerizable unsaturated bond.

5. The resin wiring board according to claim 4, wherein the resin component contained in the resin base material contains a structural unit derived from an alkyl (meth)acrylate ester.

6. The resin wiring board according to claim 5, wherein the proportion of structural units derived from the (meth)acrylic acid alkyl ester among structural units derived from monomers contained in the resin component contained in the resin base material is 21% by mass to 44% by mass.

7. The resin wiring board according to claim 4, wherein the resin base material contains a resin component and a filler, and the content of the filler in the resin base material is 5 parts by mass to 30 parts by mass per 100 parts by mass of the resin component contained in the resin base material.

8. The resin wiring board according to claim 1, wherein the resin component contained in the resin base material contains a structural unit derived from a reversible addition-fragmentation chain transfer agent.

9. The resin wiring board according to claim 1, wherein the resin component contained in the resin base material contains a structural unit derived from a compound having a siloxane bond and a polymerizable unsaturated bond.

10. The resin wiring board according to claim 1, wherein the wiring pattern has, in a cross-sectional view, an embedded portion made of metal formed along a recess formed on the first surface of the resin base material, and an exposed portion made of metal exposed from the first surface.

11. A stretchable device comprising a resin wiring board according to any one of claims 1 to 10.

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