JP2022076292A - Elastic multilayer circuit board, elastic display using the same, wearable device or biological sensor, display device and method of manufacturing elastic multilayer circuit board - Google Patents

Abstract

To provide an elastic multilayer circuit board which is excellent in the elastic electrical property.SOLUTION: An elastic multilayer circuit board of the present invention comprises a multilayer wiring structure including: a board; a plurality of pieces of lower wiring provided on the board; a lower insulating layer provided on the lower wiring; a plurality of pieces of upper wiring provided on the lower insulating layer; and an upper insulating layer provided on the upper wiring. Each of the board, lower wiring, lower insulating layer, upper wiring and upper insulating layer includes a thermosetting elastomer. The multilayer wiring structure includes an intersection structure in which the first lower wiring and the first upper wiring intersect each other when viewed in the vertical direction with respect to the one surface of the board, and a connection structure in which the first lower wiring and the first upper wiring can be electrically connected to each other.SELECTED DRAWING: Figure 1

Description

The present invention relates to a stretchable multilayer circuit board, a stretchable display using the stretchable multi-layer circuit board, a wearable device, a biosensor, a display device, and a method for manufacturing the stretchable multi-layer circuit board.

So far, various developments have been made on multi-layer circuit boards. As this kind of technique, for example, the technique described in Patent Document 1 is known. Patent Document 1 describes a multilayer circuit board in which a plurality of resin films made of a thermoplastic resin having a conductor pattern made of a metal foil are bonded to each other by heating and pressurizing (Patent Document 1). 1. Claim 1, FIG. 2 (b), etc.).

2008-198859

However, as a result of the study by the present inventor, it has been found that there is room for improvement in the expansion and contraction electrical characteristics in the multilayer circuit board described in Patent Document 1.

As a result of further study by the present inventor, the upper part of the multi-layer wiring structure, such as a substrate, wiring, and an insulating layer, is configured to include a thermosetting elastomer while improving elastic electrical characteristics. We have found that a stretchable multilayer circuit board capable of high integration can be realized by arranging an intersecting structure in which wiring and lower wiring intersect, and have completed the present invention.

According to the present invention
With the board
With a plurality of lower wirings provided on the board,
The lower insulating layer provided on the lower wiring and
A plurality of upper wirings provided on the lower insulating layer, and
An elastic multilayer circuit board comprising a multilayer wiring structure having an upper insulating layer provided on the upper wiring.
The substrate, the lower wiring, the lower insulating layer, the upper wiring, and the upper insulating layer each contain a thermosetting elastomer.
In the multilayer wiring structure,
An intersecting structure in which the first lower wiring and the first upper wiring intersect each other when viewed in a direction perpendicular to one surface of the substrate.
A connection structure in which the first lower wiring and the first upper wiring can be electrically connected to each other,
A stretchable multilayer circuit board is provided.

Further, according to the present invention.
A stretchable display, a wearable device, or a biosensor having the stretchable multilayer circuit board described above is provided.

Further, according to the present invention.
A display device including a display unit, a control unit, a power supply unit, and / or a communication unit.
A display device is provided in which the display unit includes the stretchable display described above.

Further, according to the present invention.
The process of forming the substrate and
The process of forming a plurality of lower wirings on the substrate and
The process of forming the lower insulating layer on the lower wiring and
The process of forming a plurality of upper wirings on the lower insulating layer and
A method for manufacturing an elastic multilayer circuit board having a multilayer wiring structure, comprising a step of forming an upper insulating layer on the upper wiring.
The substrate, the lower wiring, the lower insulating layer, the upper wiring, and the upper insulating layer are each formed by using a thermosetting elastomer.
When viewed in a direction perpendicular to one surface of the substrate, the lower wiring so that the first upper wiring intersects with at least the first lower wiring but can be electrically connected to each other. And to form the upper wiring,
A method for manufacturing a stretchable multilayer circuit board is provided.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a stretchable multilayer circuit board having excellent stretchable electrical characteristics, a stretchable display, a wearable device, or a biosensor, a display device, and a method for manufacturing a stretchable multilayer circuit board using the stretchable multilayer circuit board.

(A) It is a top view schematically showing the structure of the stretchable multilayer circuit board which concerns on this embodiment. (B) It is an enlarged view of the area A of FIG. 1 (a). (A) to (c) are cross-sectional views of a1 to a3 of the region A of FIG. 1 (a), (d) is a cross-sectional view of the region B of FIG. FIG. 3 is a cross-sectional view taken along the line c1 of the C region. It is a figure which shows typically an example of the manufacturing process of the stretchable multilayer circuit board which concerns on this embodiment. It is a functional block diagram which shows an example of the structure of the display device provided with the elastic display which concerns on this embodiment. It is a top view schematically showing the structure of the stretchable multilayer circuit board in an Example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by the same reference numerals, and description thereof will be omitted as appropriate. Further, the figure is a schematic view and does not match the actual dimensional ratio.

The stretchable multilayer circuit board of this embodiment will be outlined.

The stretchable multilayer circuit board of the present embodiment includes a substrate, a plurality of lower wirings provided on the substrate, a lower insulating layer provided on the lower wirings, and a plurality of lower insulating layers provided on the lower insulating layer. It has a multi-layer wiring structure having an upper wiring and an upper insulating layer provided on the upper wiring, and the substrate, the lower wiring, the lower insulating layer, the upper wiring, and the upper insulating layer are each thermally curable. A multi-layer flexible stretchable substrate configured to contain an elastomer.
This elastic multi-layer circuit board has a cross-structure in which the first lower wiring and the first upper wiring intersect each other when viewed in a direction perpendicular to one surface of the substrate in the multi-layer wiring structure, and the first. It is provided with a connection structure in which the lower wiring and the first upper wiring can be electrically connected to each other.

According to the knowledge of the present inventor, each component in the multilayer wiring structure such as the substrate, the upper wiring, the lower wiring, the upper insulating layer, and the lower insulating layer is configured by using an elastomer to form a stretchable multilayer circuit board. The elastic electrical characteristics of can be improved. Further, by arranging an intersecting structure in which at least the first upper wiring and the first lower wiring intersect, it is possible to highly integrate the stretchable multilayer circuit board.
In addition, since multiple electronic components can be mounted in each of the connection structures between the plurality of upper wirings and the plurality of lower wirings, such as between the first lower wiring and the first upper wiring, the functions are integrated. It becomes easy to change.

Here, the thermoplastic resin described in Patent Document 1 may be thermally shrunk by the heat treatment at the time of wiring formation, and the connection reliability in the multilayer circuit board may be lowered. Such a problem becomes more apparent in the structure in which wiring is integrated.

On the other hand, in the stretchable multilayer circuit board of the present embodiment, the heat resistance is improved by using a thermosetting elastomer, particularly silicone rubber, as the elastomer, and the substrate size is thermally shrunk due to the heat history received in the manufacturing process. Since this can be suppressed, a multi-layer wiring structure with excellent connection reliability can be realized. Further, in the stretchable multilayer circuit board of the present embodiment, since the constituent members such as the substrate, the circuit, and the insulating layer are made of an elastic body, it is less likely to be plastically deformed as compared with the thermoplastic material.

According to this embodiment, since wiring members such as upper wiring and lower wiring can be formed by a printing method, it is possible to provide a stretchable multilayer circuit board having an excellent degree of freedom in wiring design.

The stretchable multilayer circuit board of the present embodiment can mount various electronic components like a printed wiring board.
Electronic components include, for example, light emitting elements such as LED chips, biometric meters that detect bioelectric potentials such as brain waves and myoelectric potentials, and biological activities such as blood pressure and pulse, and pressure, temperature, position, humidity, light, sound, and acceleration. Examples include general measuring meters that detect environmental information such as, portable power supplies such as capacitors, acoustic modules, communication modules, and the like.

According to this embodiment, it is possible to provide a stretchable multilayer circuit board capable of two-dimensional (plane) sensing on one surface side of the substrate.

According to this embodiment, various electronic devices such as a stretchable display, a wearable device, and a biosensor can be provided by using a stretchable multilayer circuit board. Even when deformation such as bending and expansion / contraction is required when using an electronic device, high connection reliability can be realized by using the elastic multilayer circuit board.

Hereinafter, the stretchable multilayer circuit board of the present embodiment will be described in detail.

FIG. 1A is a top view schematically showing an example of the stretchable multilayer circuit board 100 of the present embodiment.
1 (b) is an enlarged view of the A region of FIG. 1 (a), and FIGS. 2 (a) to 2 (c) are cross-sectional views taken along the three dotted lines a1 to a3 in the A region of FIG. 1 (a). 2 (d) is a cross-sectional view at the dotted line portion b1 in the B region of FIG. 1 (a), and FIG. 2 (e) is a cross-sectional view at the dotted line portion c1 in the C region of FIG. 1 (a). ..

The stretchable multilayer circuit board 100 of the present embodiment includes a stretchable board (board 110), a plurality of stretchable lower wirings (first lower wiring 120, second lower wiring 126), and a stretchable lower insulating layer (lower insulating layer). Layer 130), a plurality of elastic upper wirings (first upper wiring 150, second upper wiring 156), and elastic upper insulating layer (upper insulating layer 160).

In the present specification, the term "having elasticity" means that, for example, when the stretchable wiring is stretched in the extending direction, the stretch ratios of the constituent members such as the substrate 110, the lower wiring 120, and the upper wiring 150 are not stretched, respectively. It means that it can be extended to, for example, 10% or more, preferably 20% or more, more preferably 50% or more, and further preferably 100% with respect to the length of. When the stretchable multilayer circuit board 100 is extended in the extending direction of the lower wiring 120 and / or the upper wiring 150, the lower wiring 120 or the upper wiring 150 can be maintained in a state in which the lower wiring 120 or the upper wiring 150 is not broken within the above extension ratio range.
Here, the extending direction can be defined as a direction from one end to the other end of the portion of the lower wiring 120 or the upper wiring 150 having the longest length in the in-plane direction.

As shown in FIG. 2B, in one of the cross sections of the stretchable multilayer circuit board 100 in the stacking direction (hereinafter, may be simply referred to as “cross-sectional view”), the multilayer wiring structure 200 is the substrate 110. The lower wiring 120 provided on the substrate 110, the lower insulating layer 130 provided on the lower wiring 120, the upper wiring 150 provided on the lower insulating layer 130, and the upper wiring 150 provided on the upper wiring 150. The upper insulating layer 160 is provided.

As shown in FIGS. 1 (b) and 2 (a), the stretchable multilayer circuit board 100 is viewed in a direction perpendicular to one surface of the substrate 110 in the multilayer wiring structure 200 (hereinafter, simply “top surface”). It is also referred to as "visual"), and includes an intersecting structure 210 in which the first lower wiring 120 and the first upper wiring 150 intersect each other.

Intersection means that the extending direction of the wiring on the lower side and the extending direction of the wiring on the upper side are not the same direction but different from each other between the two wirings arranged via the insulating layer in the stacking direction. It means that the regions have overlapping regions in the top view.
In one example of the present embodiment, at least a part of the regions of the lower wiring 120 and the upper wiring 150 may intersect in the orthogonal direction, that is, so that the intersection angle is 90 degrees in the top view.

Further, in the stretchable multilayer circuit board 100, when viewed in a direction perpendicular to one surface of the substrate 110 (when viewed from above), a plurality of lower wirings and a plurality of upper wirings are mutually arranged in the multilayer wiring structure 200. It may have a plurality of intersecting structures that intersect. The plurality of intersecting structures may be arranged in a grid pattern. This makes it possible to further enhance the functional integration.

As described above, when the stretchable multilayer circuit board 100 has a plurality of crossing structures, the crossing angles in the top view of each crossing structure may be the same or different, but they are all the same from the viewpoint of integration. From the viewpoint of durability, all of them may be configured to be approximately 90 degrees.

In the present specification, the term "abbreviation" means to include a range in consideration of manufacturing tolerances, variations, etc., unless otherwise specified.

Further, as shown in FIG. 2A, the stretchable multilayer circuit board 100 includes a connection structure 220 in which the first lower wiring 120 and the first upper wiring 150 can be electrically connected to each other.

The structure and components of the connection structure 220 are not particularly limited, and the connection structure 220 has a structure in which the first lower wiring 120 and the first upper wiring 150 can be electrically connected via an electronic component 170 or the like.

In an example of the connection structure 220, the lower wiring 120 has a lower connection portion 122 that connects to the outside such as an electronic component 170, and the upper wiring 150 has an upper connection portion 152 that connects to the outside such as an electronic component 170. Have.

As shown in FIG. 1 (b), the lower connection portion 122 may be configured to be wider than the line width of the lower wiring 120 in the top view. The lower connection portion 122 functions as an electrode pad, and the connection stability in the stacking direction with the electronic component 170 can be enhanced.

The lower connection portion 122 may have a protruding connection portion as shown in FIGS. 2 (a) and 2 (b). The protruding connection portion has a structure protruding from the lower wiring 120 upward from the substrate 110 toward the lower wiring 120 in a cross-sectional view when the multilayer wiring structure 200 is cut in the stacking direction. At least, the first lower wiring 120 may have a lower connection portion 122 configured by a protruding connection portion. This makes it possible to improve the ease of connection between the lower connection portion 122 and the upper connection portion 152.

The upper connection portion 152 may be composed of a branch connection portion branched from the upper wiring 150. As shown in FIG. 1B, for example, the branch connection portion is a wiring that protrudes from the side surface of the upper wiring 150 and extends in a direction different from the extending direction of the upper wiring 150 in the same layer as the upper wiring 150. Is. This branch connection portion is formed in the vicinity of the lower connection portion 122. As a result, the integration of the stretchable multilayer circuit board 100 can be enhanced.

In the connection structure 220, a part of the lower wiring 120 and the lower insulating layer 130 may be configured in a state of being exposed without being covered by the lower insulating layer 130 and the upper insulating layer 160.

In the connection structure 220, as shown in FIG. 2A, at least a lower opening (opening 140) penetrating the lower insulating layer 130 and the upper insulating layer 160 is formed, and at least penetrates the upper insulating layer 160. An upper opening (opening 142) may be formed.
The opening 140 and the opening 142 may be independent holes, respectively, or may be composed of one hole in which two or more opening spaces are connected to each other.

When having such an opening, the first lower wiring 120 has a lower connecting portion 122 configured to be exposed within the opening 140, and the first upper wiring 150 has the opening 142. It may have an upper connection portion 152 configured to be exposed within.

As shown in FIG. 2A, the electronic component 170 is mounted on the stretchable multilayer circuit board 100 in a state of being electrically connected to, for example, the lower connection portion 122 and the upper connection portion 152 by various connection means. Will be done.

The electronic component 170 may be configured to be electrically connected to the first lower wiring 120 and the first upper wiring 150 using, for example, at least one of a conductive paste and a solder material. The conductive paste may be the same material that forms the wiring.

In the multilayer wiring structure 200, the stretchable multilayer circuit board 100 may include a sealing portion (not shown) for sealing the electronic component 170. The sealing portion may be configured to cover at least a part of the upper surface or the side surface of the electronic component 170, or may be configured to cover at least a part of the connection portion between the electronic component 170 and each wiring. This makes it possible to improve the connection stability of the electronic component 170.
As the sealing material, for example, a thermosetting elastomer may be used.

As shown in FIG. 1A, the lower wiring 120 may have a lower connecting portion 124 at an end, and the upper wiring 150 may have an upper connecting portion 154 at an end. These lower connection portions 124 and upper connection portion 154 function as electrodes that can be connected to the outside such as an external power supply.

The lower wiring 120 and the upper connecting portion 154 are configured so that at least a part thereof is not covered with a member constituting the multilayer wiring structure 200, for example, an insulating layer, and is exposed. As an example of the lower wiring 120 and the upper connecting portion 154, as shown in FIGS. 2 (d) and 2 (e), a protruding connecting portion that protrudes to the upper insulating layer 160 of the outermost layer may be configured. This makes it possible to realize a structure that is easy to connect.

In the stretchable multilayer circuit board 100, as shown in FIG. 2A, the substrate 110 does not have wiring on the other surface on the opposite side to the one on which the lower wiring 120 and the upper wiring 150 are provided. It may be configured. That is, the stretchable multilayer circuit board 100 may be a one-sided circuit board. As a result, the flexible elasticity of the stretchable multilayer circuit board 100 can be ensured, and the degree of integration of the wiring circuit can be increased.

Next, a modification of the stretchable multilayer circuit board 100 will be described.

As shown in FIG. 1A, the plurality of elastic lower wirings may be composed of at least two or more wirings of the first lower wiring 120 and the second lower wiring 126, and the plurality of elastic lower wirings may be three or more. It may have four or more wires and eight or more wires.
Similarly, as shown in FIG. 1A, the plurality of elastic upper wirings may be composed of at least two or more wirings of the first upper wiring 150 and the second upper wiring 156. It may have 3 or more, 4 or more, and 8 or more wires.
The upper limit of the number of wirings of the plurality of elastic lower wirings and the plurality of elastic upper wirings can be set as needed and is not particularly limited.

The plurality of elastic lower wirings and the plurality of elastic upper wirings may have one or two or more wirings having wiring portions parallel to each other in the top view.

The first lower wiring 120 and the second lower wiring 126 are arranged at least in part or in whole in the same lower wiring layer. At least a part or the whole of the first lower wiring 120 and the second lower wiring 126 may be formed so as to be in contact with one surface of the substrate 110.

Further, at least a part or the whole of the first upper wiring 150 and the second upper wiring 156 are arranged in the same upper wiring layer. At least a part or all of the first upper wiring 150 and the second upper wiring 156 may be formed so as to be in contact with one surface of the lower insulating layer 130 located between the lower wiring and the upper wiring.
A part of the first upper wiring 150 and the second upper wiring 156 is in contact with one surface of the substrate 110 and is formed in the same layer as the first lower wiring 120 and the second lower wiring 126. You may.

The multilayer wiring structure 200 may have one or two or more other wiring layers on the upper insulating layer 160. That is, the number of wiring layers of the multilayer wiring structure 200 is not limited to the two layers shown in FIG. 2A, and may be three or more layers or four or more layers, if necessary. In this case, at least one or more insulating layers are formed between the re-adjacent wiring layers in the stacking direction.

The stretchable multilayer circuit board 100 may have at least one crossed structure 210, and may have, for example, a value obtained by integrating the number of wirings of the upper wiring and the number of wirings of the lower wiring. Examples of the plurality of intersecting structures include a first intersecting structure 210 of the lower wiring 120 and the upper wiring 150, a second intersecting structure 212 of the lower wiring 120 and the upper wiring 156, and the like.

The position of the connection surface of the upper connection portion 152 may be arranged in any of the layers of the lower insulation layer 130, the upper wiring 150, and the upper insulation layer 160, but the position is substantially the same as the connection surface of the upper connection portion 152. It may be configured.

The lower wiring 120 and the lower connecting portion 122 may be formed by a printing method using a conductive paste, that is, may be composed of a printing layer. Further, the upper wiring 150 and the upper connecting portion 152 may also be formed by a printing method using a conductive paste, that is, may be composed of a printing layer.
As a result, the wiring and the connection portion can be formed almost seamlessly, and the boundaries between the wirings can be almost eliminated.

At least one of the lower insulating layer 130 and the upper insulating layer 160 may be configured such that a plurality of insulating layers are separated from each other in the same layer, or may be configured by one insulating layer.

In the cross-sectional view, the multilayer wiring structure 200 has a region where the upper insulating layer 160 exists on the lower insulating layer 130, a region where the upper insulating layer 160 does not exist on the lower insulating layer 130, and a lower insulating under the upper insulating layer 160. The layer 130 may have at least one of the non-existent regions.

Even if the above-mentioned opening is composed of at least one of a through hole penetrating the insulating layer, a separated portion in which a plurality of insulating layers are separated from each other, and an uncoated portion in which the substrate 110 is not covered by the insulating layer in a top view. good.

The opening 140 and the opening 142 in FIG. 2 may be composed of voids, but may be filled with a material or the like constituting an insulating layer. The void structure makes it difficult for stress generated during expansion and contraction of the stretchable multilayer circuit board 100 to be transmitted to the connection portion of the electronic component 170, and enhances connection reliability during expansion and contraction. On the other hand, by adopting a filling structure, it is possible to suppress the entry of foreign substances such as dust into the opening and to prevent the connection portion from being exposed to the external environment, so that long-term connection reliability can be improved.

An example of the void structure is a separation portion around the connection portion between the electronic component 170 and the lower connection portion 122 and the upper connection portion 152 so as not to come into contact with the insulation layer such as the upper insulation layer 160. The structure in which is present can be mentioned.

The electronic component 170 may be partially or wholly embedded in an opening formed in an insulating layer, such as an opening 140 and an opening 142. As a result, the connection stability of the electronic component 170 can be improved.
When sealing the periphery of the electronic component 170, the entire electronic component 170 may be provided outside the opening.

The thickness ratio expressed by the thickness of the wiring / the thickness of the insulating layer is, for example, 0.05 to 20.0, preferably 0.08 to 15.0, and more preferably 0.1 to 10.0. Within such a range, conductivity and insulation can be improved.
The thickness ratio expressed by the thickness of the insulating layer / the thickness of the substrate is, for example, 0.01 to 2.0, preferably 0.05 to 1.0, and more preferably 0.08 to 0.7. Within such a range, flexibility and insulation can be improved.

The thickness ratio may be satisfied by at least one of the lower wiring 120 and the upper wiring 150, preferably by both wirings, and may be satisfied by at least one insulating layer of the lower insulating layer 130 and the upper insulating layer 160. It is preferred that both insulating layers fill.

The upper limit of the thickness of the substrate 110 can be set according to the application, and may be, for example, 10 mm or less, preferably 1 mm or less, but more preferably 400 μm or less from the viewpoint of wearable device applications. By setting the thickness to 400 μm or less, a thin film stretchable multilayer circuit board 100 can be realized.
From the viewpoint of mechanical strength, the lower limit of the thickness of the substrate 110 is, for example, 10 μm or more, preferably 50 μm or more, and more preferably 100 μm or more.

Next, the materials and characteristics constituting the stretchable multilayer circuit board 100 will be described.

In this embodiment, the substrate 110, the lower wiring 120, the lower insulating layer 130, the upper wiring 150, and the upper insulating layer 160 each contain the same and / or different thermosetting elastomers, preferably the same thermosetting elastomer. May be configured to include.
More specifically, the lower wiring 120 and the upper wiring 150 may be made of the same and / or different conductive elastomers, respectively, and the substrate 110, the lower insulating layer 130, and the upper insulating layer 160 are the same and respectively. / Or may be composed of different insulating elastomers.

The insulating elastomer can include, for example, a thermosetting elastomer such as silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, and ethylene propylene rubber. Among these, the insulating elastomer may contain one or more selected from the group consisting of silicone rubber, urethane rubber, and fluororubber, and may be preferably composed of silicone rubber. Silicone rubber is chemically stable among elastomers and has excellent mechanical strength.

The insulating elastomer does not contain a conductive filler and may contain a non-conductive filler. This enhances the mechanical properties of the conductive elastomer. As the non-conductive filler, a known material can be used, but for example, an inorganic filler may be used. As the inorganic filler, silica particles, silicone rubber particles, talc and the like may be used.

The conductive elastomer can include, for example, a thermosetting elastomer such as silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, and ethylene propylene rubber, and a conductive filler. Among these, the conductive elastomer may contain one or more selected from the group consisting of silicone rubber, urethane rubber, and fluororubber, and may be preferably configured to contain silicone rubber and a conductive filler. As a result, the elasticity and electrical characteristics of the conductive elastomer can be enhanced.

Examples of the conductive filler include powdery or fibrous metal-based fillers, carbon-based fillers, metal oxide fillers, metal-plated fillers and the like. Among these, as the conductive filler, a metal-based filler, preferably silver powder, may be used.
Further, the conductive elastomer may contain a non-conductive filler together with the conductive filler. This makes it possible to increase the durability of expansion and contraction.

As an example of this embodiment, the substrate 110, the lower wiring 120, the lower insulating layer 130, the upper wiring 150, and the upper insulating layer 160 may each contain the same thermosetting elastomer. As a result, the adhesion to each other can be improved, so that the stretch durability of the stretchable multilayer circuit board 100 can be improved.

In the present specification, including the same thermosetting elastomer, including the same insulating elastomer, and containing the same conductive elastomer, respectively, means at least one of the types of thermosetting elastomers exemplified above. Means to contain more than one elastomer of the same type.

More specifically, the substrate 110, the lower insulating layer 130, and the upper insulating layer 160 may each be configured to contain the same silicone rubber. This makes it possible to improve the adhesion between the layers. Further, the withstand voltage can be increased in the insulating layer sandwiched between the upper and lower wirings.

The substrate 110, the lower insulating layer 130, and the upper insulating layer 160 may be configured such that at least one, preferably all, contains an inorganic filler. This makes it possible to appropriately improve these mechanical properties.

Further, the lower wiring 120 and the upper wiring 150 may be configured to contain the same silicone rubber and conductive filler, respectively. As a result, the elasticity and the conductivity can be enhanced.

At least one of the lower wiring 120 and the upper wiring 150 may preferably be configured to include all of the inorganic fillers. This makes it possible to improve the mechanical properties as well as the conductivity.

The substrate 110, the lower wiring 120, the lower insulating layer 130, the upper wiring 150, and the upper insulating layer 160 may each be configured to contain the same type of silicone rubber. As a result, the adhesion between the layers can be enhanced. In addition, durability during expansion and contraction can be improved.

Here, the components in the silicone rubber-based curable composition will be described in detail.

Here, the inclusion of the same silicone rubber means that the silicone rubber-based curable composition contains at least the same kind of vinyl group-containing linear organopolysiloxane, and further, the same kind of cross-linking agent and the same kind. It may contain one or more selected from the group consisting of non-conductive fillers, the same type of silane coupling agent, and the same type of catalyst.

The insulating silicone rubber may be composed of a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane.
Further, the conductive silicone rubber may be composed of a conductive filler and a cured product of a silicone rubber-based curable composition containing a vinyl group-containing organopolysiloxane.

The vinyl group-containing linear organopolysiloxane of the same type may contain at least the same vinyl group as the functional group and may have a linearity, and the vinyl group amount, the molecular weight distribution, or the addition amount thereof in the molecule may be. It may be different.

The cross-linking agent of the same type may have at least a common structure such as a linear structure or a branched structure, may contain a molecular weight distribution in the molecule or a different functional group, and the addition amount thereof is different. You may.

The non-conductive fillers of the same type may have at least a common constituent material, and may differ in particle size, specific surface area, surface treatment agent, or addition amount thereof.

The silane coupling agent of the same type may have at least a common functional group, and other functional groups in the molecule and the amount added may be different.

The catalysts of the same type may have at least a common constituent material, and the catalysts may contain different compositions or may have different addition amounts.

The silicone rubber-based curable composition constituting the same silicone rubber further comprises different types of vinyl group-containing linear organopolysiloxanes, cross-linking agents, non-conductive fillers, silane coupling agents, and catalysts. It may include one or more selected from the group.

The silicone rubber-based curable composition of the present embodiment can contain a vinyl group-containing organopolysiloxane (A). The vinyl group-containing organopolysiloxane (A) is a polymer which is a main component of the silicone rubber-based curable composition of the present embodiment.

The vinyl group-containing organopolysiloxane (A) can include a vinyl group-containing linear organopolysiloxane (A1) having a linear structure.

The vinyl group-containing linear organopolysiloxane (A1) has a linear structure and contains a vinyl group, and the vinyl group serves as a cross-linking point at the time of curing.

The content of the vinyl group of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably, for example, having two or more vinyl groups in the molecule and 15 mol% or less. .. As a result, the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) is optimized, and a network with each component described later can be reliably formed.

In the present specification, the vinyl group content is the mol% of the vinyl group-containing siloxane unit when all the units constituting the vinyl group-containing linear organopolysiloxane (A1) are 100 mol%. .. However, it is considered that there is one vinyl group for each vinyl group-containing siloxane unit.

The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of, for example, preferably about 1000 to 10000, and more preferably about 2000 to 5000. The degree of polymerization can be determined, for example, as the polystyrene-equivalent number average degree of polymerization (or number average molecular weight) in GPC (gel permeation chromatography) using chloroform as a developing solvent.
In the present specification, "to" means that an upper limit value and a lower limit value are included unless otherwise specified.

Further, the specific gravity of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of about 0.9 to 1.1.

By using a vinyl group-containing linear organopolysiloxane (A1) having a degree of polymerization and specific gravity within the above range, the silicone rubber obtained has heat resistance, flame retardancy, chemical stability, etc. Can be improved.

The vinyl group-containing linear organopolysiloxane (A1) preferably has a structure represented by the following formula (1).

In formula (1), R ¹ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like, and among them, a vinyl group is preferable. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group and the like.

Further, R ² is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, and a butenyl group. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

Further, R ³ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group.

Further, examples of the substituent of R ¹ and R ² in the formula (1) include a methyl group, a vinyl group and the like, and examples of the substituent of R ³ include a methyl group and the like.

In the equation (1), the plurality of R ^1s are independent of each other and may be different from each other or may be the same. The same applies to R ² and R ³ .

Further, m and n are the number of repeating units constituting the vinyl group-containing linear organopolysiloxane (A1) represented by the formula (1), m is an integer of 0 to 2000, and n is 1000 to 10000. Is an integer of. m is preferably 0 to 1000, and n is preferably 2000 to 5000.

Moreover, as a specific structure of the vinyl group-containing linear organopolysiloxane (A1) represented by the formula (1), for example, the one represented by the following formula (1-1) can be mentioned.

In formula (1-1), R ¹ and R ² are each independently a methyl group or a vinyl group, and at least one of them is a vinyl group.

The vinyl group-containing linear organopolysiloxane (A1) is a first vinyl group-containing linear siloxane having a vinyl group content of 2 or more in the molecule and 0.4 mol% or less. Organopolysiloxane (A1-1) may be included. The vinyl group amount of the first vinyl group-containing linear organopolysiloxane (A1-1) may be 0.1 mol% or less.

The vinyl group-containing linear organopolysiloxane (A1) has a vinyl group content of 0.5 to 15 mol% with the first vinyl group-containing linear organopolysiloxane (A1-1). May contain a vinyl group-containing linear organopolysiloxane (A1-2).

As raw rubber which is a raw material of silicone rubber, a first vinyl group-containing linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) having a high vinyl group content are used. ), The vinyl groups can be unevenly distributed, and the cross-linking density can be more effectively formed in the cross-linking network of the silicone rubber. As a result, the tear strength of the silicone rubber can be increased more effectively.

Specifically, as the vinyl group-containing linear organopolysiloxane (A1), for example, in the above formula (1-1), a unit in which R1 is a vinyl group and / or a unit in which R2 is a vinyl group is a molecule. A first vinyl group-containing linear organopolysiloxane (A1-1) having two or more of them and containing 0.4 mol% or less, and a unit in which R1 is a vinyl group and / or R2 is a vinyl group. It is preferable to use a second vinyl group-containing linear organopolysiloxane (A1-2) containing 0.5 to 15 mol% of the unit.

Further, the first vinyl group-containing linear organopolysiloxane (A1-1) preferably has a vinyl group content of 0.01 to 0.2 mol%. Further, the vinyl group-containing linear organopolysiloxane (A1-2) preferably has a vinyl group content of 0.8 to 12 mol%.

Further, when the first vinyl group-containing linear organopolysiloxane (A1-1) and the second vinyl group-containing linear organopolysiloxane (A1-2) are blended in combination (A1-1). The ratio of and (A1-2) is not particularly limited, but for example, the weight ratio of (A1-1) :( A1-2) is preferably 50:50 to 95: 5, and 80:20 to 90: It is more preferably 10.

The first and second vinyl group-containing linear organopolysiloxanes (A1-1) and (A1-2) may be used alone or in combination of two or more. good.

Further, the vinyl group-containing organopolysiloxane (A) may contain a vinyl group-containing branched organopolysiloxane (A2) having a branched structure.

<< Organohydrogen Polysiloxane (B) >>
The silicone rubber-based curable composition of the present embodiment can contain organohydrogenpolysiloxane (B).
The organohydrogenpolysiloxane (B) is classified into a linear organohydrogenpolysiloxane (B1) having a linear structure and a branched organohydrogenpolysiloxane (B2) having a branched structure. Either one or both can be included.

The linear organohydrogenpolysiloxane (B1) has a linear structure and a structure (≡Si—H) in which hydrogen is directly bonded to Si, and is a vinyl group-containing organopolysiloxane (A). In addition to the vinyl group, it is a polymer that undergoes a hydrosilylation reaction with the vinyl group contained in the components contained in the silicone rubber-based curable composition and crosslinks these components.

The molecular weight of the linear organohydrogenpolysiloxane (B1) is not particularly limited, but for example, the weight average molecular weight is preferably 20000 or less, and more preferably 1000 or more and 10000 or less.

The weight average molecular weight of the linear organohydrogenpolysiloxane (B1) can be measured, for example, by polystyrene conversion in GPC (gel permeation chromatography) using chloroform as a developing solvent.

Further, the linear organohydrogenpolysiloxane (B1) is usually preferably one having no vinyl group. This makes it possible to accurately prevent the cross-linking reaction from proceeding in the molecule of the linear organohydrogenpolysiloxane (B1).

As the linear organohydrogenpolysiloxane (B1) as described above, for example, one having a structure represented by the following formula (2) is preferably used.

In formula (2), ^R4 is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, a hydrocarbon group combining these, or a hydride group. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

Further, R5 is a substituted or unsubstituted alkyl group having 1 to ¹⁰ carbon atoms, an alkenyl group, an aryl group, a hydrocarbon group combining these, or a hydride group. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group and a propyl group, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

In the equation (2), the plurality of R ^4s are independent of each other and may be different from each other or may be the same. The ^same applies to R5. However, of the plurality of ^R4 and R5, at ^least two or more are hydride groups.

Further, R ⁶ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group in which these are combined. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. The plurality of ^R6s are independent of each other and may be different from each other or may be the same.

Examples of the substituent of R ⁴ , R ⁵ , and R ⁶ in the formula (2) include a methyl group and a vinyl group, and a methyl group is preferable from the viewpoint of preventing an intramolecular cross-linking reaction.

Further, m and n are the number of repeating units constituting the linear organohydrogenpolysiloxane (B1) represented by the formula (2), where m is an integer of 2 to 150 and n is an integer of 2 to 150. Is. Preferably, m is an integer of 2 to 100 and n is an integer of 2 to 100.

The linear organohydrogenpolysiloxane (B1) may be used alone or in combination of two or more.

Since the branched organohydrogenpolysiloxane (B2) has a branched structure, it forms a region having a high crosslink density and is a component that greatly contributes to the formation of a dense structure having a crosslink density in the silicone rubber system. Further, like the linear organohydrogenpolysiloxane (B1), it has a structure (≡Si—H) in which hydrogen is directly bonded to Si, and in addition to the vinyl group of the vinyl group-containing organopolysiloxane (A), silicone. It is a polymer that undergoes a hydrosilylation reaction with the vinyl group of the component contained in the rubber-based curable composition and crosslinks these components.

The specific gravity of the branched organohydrogenpolysiloxane (B2) is in the range of 0.9 to 0.95.

Further, the branched organohydrogenpolysiloxane (B2) is usually preferably one having no vinyl group. This makes it possible to accurately prevent the cross-linking reaction from proceeding in the molecule of the branched organohydrogenpolysiloxane (B2).

The branched organohydrogenpolysiloxane (B2) is preferably represented by the following average composition formula (c).

Average composition formula (c)
(H _a (R ⁷ ) _3-a SiO _1/2 ) _m (SiO _4/2 ) _n
(In the formula (c), R ⁷ is a monovalent organic group, a is an integer in the range of 1 to 3, m is _a number of Ha (R ⁷ ) _3-a SiO _1/2 units, and n is SiO _{4 /.} It is a number of ₂ units)

In formula (c), R ⁷ is a monovalent organic group, preferably a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an aryl group, or a hydrocarbon group in combination thereof. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

In the formula (c), a is the number of hydride groups (hydrogen atoms directly bonded to Si), and is an integer in the range of 1 to 3, preferably 1.

Further, in the formula ( _c ), m is the number of Ha (R ⁷ ) _3-a SiO _1/2 unit, and n is the number of SiO _4/2 unit.

The branched organohydrogenpolysiloxane (B2) has a branched structure. The linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) differ in that their structure is linear or branched, and the Si is the same as when the number of Si is 1. The number of alkyl groups R to be bonded (R / Si) is 1.8 to 2.1 for the linear organohydrogenpolysiloxane (B1) and 0.8 to 1 for the branched organohydrogenpolysiloxane (B2). It is in the range of 0.7.

Since the branched organohydrogenpolysiloxane (B2) has a branched structure, for example, the amount of residue when heated to 1000 ° C. at a heating rate of 10 ° C./min under a nitrogen atmosphere is 5% or more. Will be. On the other hand, since the linear organohydrogenpolysiloxane (B1) is linear, the amount of residue after heating under the above conditions is almost zero.

Further, specific examples of the branched organohydrogenpolysiloxane (B2) include those having a structure represented by the following formula (3).

In formula (3), R ⁷ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, an aryl group, or a hydrocarbon group in combination thereof, or a hydrogen atom. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the aryl group having 1 to 8 carbon atoms include a phenyl group. Examples of the substituent of R ⁷ include a methyl group and the like.

In the equation (3), the plurality of R ^7s are independent of each other and may be different from each other or may be the same.

Further, in the equation (3), "-O-Si≡" indicates that Si has a branched structure that spreads three-dimensionally.

The branched organohydrogenpolysiloxane (B2) may be used alone or in combination of two or more.

Further, in the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2), the amount of hydrogen atoms (hydride groups) directly bonded to Si is not particularly limited. However, in the silicone rubber-based curable composition, the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpoly are added to 1 mol of the vinyl group in the vinyl group-containing linear organopolysiloxane (A1). The total amount of hydride group of siloxane (B2) is preferably 0.5 to 5 mol, more preferably 1 to 3.5 mol. This ensures that a crosslinked network is formed between the linear organohydrogenpolysiloxane (B1) and the branched organohydrogenpolysiloxane (B2) and the vinyl group-containing linear organopolysiloxane (A1). Can be made to.

<< Silica particles (C) >>
The silicone rubber-based curable composition of the present embodiment may contain silica particles (C) as a non-conductive filler, if necessary.

The silica particles (C) are not particularly limited, but for example, fumed silica, calcined silica, precipitated silica and the like are used. These may be used alone or in combination of two or more.

The specific surface area of the silica particles (C) by, for example, the BET method is preferably, for example, 50 to 400 m ² / g, and more preferably 100 to 400 m ² / g. The average primary particle size of the silica particles (C) is preferably, for example, 1 to 100 nm, and more preferably about 5 to 20 nm.

By using the silica particles (C) within the range of the specific surface area and the average particle size, it is possible to improve the hardness and mechanical strength of the formed silicone rubber, particularly the tensile strength.

<< Silane Coupling Agent (D) >>
The silicone rubber-based curable composition of the present embodiment can contain a silane coupling agent (D).
The silane coupling agent (D) can have a hydrolyzable group. The hydrolyzing group is hydrolyzed by water to become a hydroxyl group, and this hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl group on the surface of the silica particles (C), whereby the surface of the silica particles (C) can be modified.

Further, the silane coupling agent (D) can include a silane coupling agent having a hydrophobic group. As a result, this hydrophobic group is imparted to the surface of the silica particles (C), so that the cohesive force of the silica particles (C) is reduced in the silicone rubber-based curable composition and thus in the silicone rubber (hydrogen due to the silanol group). Aggregation due to bonding is reduced), and as a result, it is presumed that the dispersibility of the silica particles in the silicone rubber-based curable composition is improved. As a result, the interface between the silica particles and the rubber matrix increases, and the reinforcing effect of the silica particles increases. Further, it is presumed that the slipperiness of the silica particles in the matrix is improved when the rubber matrix is deformed. Then, by improving the dispersibility and slipperiness of the silica particles (C), the mechanical strength (for example, tensile strength, tear strength, etc.) of the silicone rubber due to the silica particles (C) is improved.

Further, the silane coupling agent (D) can include a silane coupling agent having a vinyl group. As a result, a vinyl group is introduced on the surface of the silica particles (C). Therefore, when the silicone rubber-based curable composition is cured, that is, the vinyl group of the vinyl group-containing organopolysiloxane (A) and the hydride group of the organohydrogenpolysiloxane (B) undergo a hydrosilylation reaction. When the network (crosslinked structure) formed by these is formed, the vinyl group of the silica particles (C) is also involved in the hydrosilylation reaction with the hydride group of the organohydrogenpolysiloxane (B). Silica particles (C) will also be incorporated into the. As a result, it is possible to reduce the hardness and increase the modulus of the formed silicone rubber.

As the silane coupling agent (D), a silane coupling agent having a hydrophobic group and a silane coupling agent having a vinyl group can be used in combination.

Examples of the silane coupling agent (D) include those represented by the following formula (4).

Y _n -Si- (X) _4-n ... (4)
In the above equation (4), n represents an integer of 1 to 3. Y represents any functional group having a hydrophobic group, a hydrophilic group or a vinyl group, and when n is 1, it is a hydrophobic group, and when n is 2 or 3, at least one of them is. It is a hydrophobic group. X represents a hydrolyzable group.

The hydrophobic group is an alkyl group having 1 to 6 carbon atoms, an aryl group, or a hydrocarbon group in which these are combined, and examples thereof include a methyl group, an ethyl group, a propyl group, a phenyl group, and the like. Methyl groups are preferred.

Examples of the hydrophilic group include a hydroxyl group, a sulfonic acid group, a carboxyl group, a carbonyl group and the like, and a hydroxyl group is particularly preferable. The hydrophilic group may be contained as a functional group, but is preferably not contained from the viewpoint of imparting hydrophobicity to the silane coupling agent (D).

Further, examples of the hydrolyzable group include an alkoxy group such as a methoxy group and an ethoxy group, a chloro group or a silazane group, and among them, a silazane group is preferable because it has high reactivity with the silica particles (C). Those having a silazane group as a hydrolyzable group have two structures of ( _Yn —Si—) in the above formula (4) due to their structural characteristics.

Specific examples of the silane coupling agent (D) represented by the above formula (4) include, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, and methyltri as having a hydrophobic group as a functional group. Ekoxysilanes such as ethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane; methyltrichlorosilane , Dimethyldichlorosilane, trimethylchlorosilane, chlorosilanes such as phenyltrichlorosilane; hexamethyldisilazane, examples of which have a vinyl group as a functional group include methacrypropyltriethoxysilane, methacrypropyltrimethoxysilane, methacryoxy. Ekkasilanes such as propylmethyldiethoxysilane, methacrypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane, vinylmethyldichlorosilane; divinyltetramethyldi Examples thereof include silazane, but in consideration of the above description, hexamethyldisilazane is particularly preferable as having a hydrophobic group, and divinyltetramethyldisilazane is preferable as having a vinyl group.

In the present embodiment, the lower limit of the content of the silane coupling agent (D) is preferably 1% by mass or more with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). It is more preferably 5% by mass or more, and further preferably 5% by mass or more. The upper limit of the content of the silane coupling agent (D) is preferably 100% by mass or less, preferably 80% by mass or less, based on 100 parts by mass of the total amount of the vinyl group-containing organopolysiloxane (A). It is more preferably present, and further preferably 40% by mass or less.
By setting the content of the silane coupling agent (D) to the above lower limit value or more, the silicone rubber has an appropriate adhesion to the substrate, and when the silica particles (C) are used, the silicone rubber as a whole It can contribute to the improvement of the mechanical strength of. Further, by setting the content of the silane coupling agent (D) to the above upper limit value or less, the silicone rubber can have appropriate mechanical properties.

<< Platinum or platinum compound (E) >>
The silicone rubber-based curable composition of the present embodiment can contain platinum or a platinum compound (E).
Platinum or the platinum compound (E) is a catalytic component that acts as a catalyst during curing. The amount of platinum or the platinum compound (E) added is the amount of the catalyst.

As the platinum or the platinum compound (E), known ones can be used, for example, platinum black, platinum supported on silica, carbon black or the like, platinum chloride acid or an alcohol solution of platinum chloride acid, chloride. Examples thereof include a complex salt of platinum acid and olefin, and a complex salt of platinum chloride acid and vinyl siloxane.

As the platinum or the platinum compound (E), only one type may be used alone, or two or more types may be used in combination.

<< Water (F) >>
Further, the silicone rubber-based curable composition of the present embodiment may contain water (F) in addition to the above components (A) to (E).

Water (F) functions as a dispersion medium for dispersing each component contained in the silicone rubber-based curable composition, and is a component that contributes to the reaction between the silica particles (C) and the silane coupling agent (D). .. Therefore, in the silicone rubber, the silica particles (C) and the silane coupling agent (D) can be more reliably connected to each other, and uniform characteristics can be exhibited as a whole.

Further, when water (F) is contained, the content thereof can be appropriately set, but specifically, for example, 10 to 100 parts by weight with respect to 100 parts by weight of the silane coupling agent (D). It is preferably in the range of 30 to 70 parts by weight, and more preferably in the range of 30 to 70 parts by weight. This makes it possible to more reliably proceed the reaction between the silane coupling agent (D) and the silica particles (C).

(Other ingredients)
Further, the silicone rubber-based curable composition of the present embodiment may further contain other components in addition to the above components (A) to (F). Other components include silica particles (C) such as diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, and mica. Examples thereof include additives such as inorganic fillers, reaction inhibitors, dispersants, pigments, dyes, antioxidants, antioxidants, flame retardants, and thermal conductivity improvers.

In the silicone rubber-based curable composition, the content ratio of each component is not particularly limited, but is set as follows, for example.

In the present embodiment, the upper limit of the content of the silica particles (C) may be, for example, 60 parts by weight or less, preferably 50 parts by weight, based on 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A). It may be less than or equal to, and more preferably 40 parts by weight or less. This makes it possible to balance mechanical strength such as hardness and tensile strength. The lower limit of the content of the silica particles (C) is not particularly limited with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), but may be, for example, 10 parts by weight or more.

The silane coupling agent (D) is preferably contained, for example, in a proportion of 5 parts by weight or more and 100 parts by weight or less of the silane coupling agent (D) with respect to 100 parts by weight of the vinyl group-containing organopolysiloxane (A). More preferably, it is contained in a proportion of 5 parts by weight or more and 40 parts by weight or less. Thereby, the dispersibility of the silica particles (C) in the silicone rubber-based curable composition can be surely improved.

The content of the organohydrogenpolysiloxane (B) is specifically, for example, with respect to 100 parts by weight of the total amount of the vinyl group-containing organopolysiloxane (A), the silica particles (C) and the silane coupling agent (D). , 0.5 part by weight or more and preferably 20 parts by weight or less, and more preferably 0.8 parts by weight or more and 15 parts by weight or less. When the content of (B) is within the above range, a more effective curing reaction may be possible.

The content of platinum or the platinum compound (E) means the amount of catalyst and can be appropriately set, but specifically, vinyl group-containing organopolysiloxane (A), silica particles (C), and silane coupling agent ( The amount of the platinum group metal in this component is 0.01 to 1000 ppm by weight, preferably 0.1 to 500 ppm, based on the total amount of D). By setting the content of platinum or the platinum compound (E) to the above lower limit value or more, the obtained silicone rubber composition can be sufficiently cured. By setting the content of platinum or the platinum compound (E) to the above upper limit value or less, the curing rate of the obtained silicone rubber composition can be improved.

Further, when water (F) is contained, the content thereof can be appropriately set, but specifically, for example, 10 to 100 parts by weight with respect to 100 parts by weight of the silane coupling agent (D). It is preferably in the range of 30 to 70 parts by weight, and more preferably in the range of 30 to 70 parts by weight. This makes it possible to more reliably proceed the reaction between the silane coupling agent (D) and the silica particles (C).

<Manufacturing method of silicone rubber>
Next, a method for manufacturing the silicone rubber of the present embodiment will be described.
As a method for producing a silicone rubber of the present embodiment, a silicone rubber-based curable composition can be prepared, and the silicone rubber-based curable composition can be cured to obtain a silicone rubber.
The details will be described below.

First, each component of the silicone rubber-based curable composition is uniformly mixed by an arbitrary kneading device to prepare a silicone rubber-based curable composition.

[1] For example, a vinyl group-containing organopolysiloxane (A), silica particles (C), and a silane coupling agent (D) are weighed in a predetermined amount and then kneaded by an arbitrary kneading device. A kneaded product containing each of these components (A), (C) and (D) is obtained.

The kneaded product is preferably obtained by kneading the vinyl group-containing organopolysiloxane (A) and the silane coupling agent (D) in advance, and then kneading (mixing) the silica particles (C). This further improves the dispersibility of the silica particles (C) in the vinyl group-containing organopolysiloxane (A).

Further, when obtaining this kneaded product, water (F) may be added to the kneaded product of each component (A), (C), and (D) as needed. This makes it possible to more reliably proceed the reaction between the silane coupling agent (D) and the silica particles (C).

Further, it is preferable that the kneading of each component (A), (C), and (D) goes through a first step of heating at the first temperature and a second step of heating at the second temperature. Thereby, in the first step, the surface of the silica particles (C) can be surface-treated with the coupling agent (D), and in the second step, the silica particles (C) and the coupling agent (D) are combined. By-products produced by the reaction can be reliably removed from the kneaded product. Then, if necessary, the component (A) may be added to the obtained kneaded product and further kneaded. This makes it possible to improve the familiarity of the components of the kneaded product.

The first temperature is preferably, for example, about 40 to 120 ° C., and more preferably about 60 to 90 ° C., for example. The second temperature is, for example, preferably about 130 to 210 ° C, more preferably about 160 to 180 ° C.

Further, the atmosphere in the first step is preferably under an inert atmosphere such as under a nitrogen atmosphere, and the atmosphere in the second step is preferably under a reduced pressure atmosphere.

Further, the time of the first step is preferably, for example, about 0.3 to 1.5 hours, and more preferably about 0.5 to 1.2 hours. The time of the second step is, for example, preferably about 0.7 to 3.0 hours, and more preferably about 1.0 to 2.0 hours.

By setting the first step and the second step under the above-mentioned conditions, the above-mentioned effect can be obtained more remarkably.

[2] Next, the organohydrogenpolysiloxane (B) and platinum or the platinum compound (E) are weighed in a predetermined amount, and then the kneaded product prepared in the above step [1] using an arbitrary kneading device. By kneading each component (B) and (E), a silicone rubber-based curable composition is obtained. The obtained silicone rubber-based curable composition may be a paste containing a solvent.

When kneading the respective components (B) and (E), the kneaded product previously prepared in the above step [1] and the organohydrogenpolysiloxane (B) were prepared in the above step [1]. It is preferable to knead the kneaded product with platinum or the platinum compound (E), and then knead the respective kneaded products. This ensures that each component (A) to (E) is contained in the silicone rubber-based curable composition without proceeding with the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B). Can be dispersed in.

The temperature at which each component (B) and (E) is kneaded is preferably, for example, about 10 to 70 ° C., more preferably about 25 to 30 ° C. as the roll set temperature.

Further, the kneading time is preferably, for example, about 5 minutes to 1 hour, and more preferably about 10 to 40 minutes.

By setting the temperature within the above range in the above step [1] and the above step [2], the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) is more accurately performed. Can be prevented or suppressed. Further, in the above steps [1] and the above steps [2], by setting the kneading time within the above range, each component (A) to (E) is more reliably dispersed in the silicone rubber-based curable composition. Can be done.

The kneading device used in each of the steps [1] and [2] is not particularly limited, and for example, a kneader, two rolls, a Banbury mixer (continuous kneader), a pressurized kneader, or the like can be used.

Further, in this step [2], a reaction inhibitor such as 1-ethynylcyclohexanol may be added to the kneaded product. As a result, even if the temperature of the kneaded product is set to a relatively high temperature, the progress of the reaction between the vinyl group-containing organopolysiloxane (A) and the organohydrogenpolysiloxane (B) is more accurately prevented or suppressed. be able to.

[3] Next, the silicone rubber is formed by curing the silicone rubber-based curable composition.

In the present embodiment, the curing step of the silicone rubber-based curable resin composition is, for example, heating (primary curing) at 100 to 250 ° C. for 1 to 30 minutes and then post-baking (secondary curing) at 200 ° C. for 1 to 4 hours. ) Is done.

Through the above steps, a silicone rubber made of a cured product of a silicone rubber-based curable resin composition can be obtained.

[3] Next, the insulating paste can be obtained by dissolving the silicone rubber-based curable composition obtained in the step [2] in a solvent.
Further, [3] Next, the silicone rubber-based curable composition obtained in the step [2] is dissolved in a solvent, and a conductive filler is added to obtain a conductive paste.

(solvent)
Conductive pastes and insulating pastes contain solvents.
As the solvent, various known solvents can be used, and for example, a high boiling point solvent can be included. These may be used alone or in combination of two or more.

The lower limit of the boiling point of the high boiling point solvent is, for example, 100 ° C. or higher, preferably 130 ° C. or higher, and more preferably 150 ° C. or higher. This makes it possible to improve printing stability such as screen printing. On the other hand, the upper limit of the boiling point of the high boiling point solvent is not particularly limited, but may be, for example, 300 ° C. or lower, 290 ° C. or lower, or 280 ° C. or lower. As a result, excessive heat history at the time of wiring formation can be suppressed, so that damage to the substrate and the shape of the wiring formed of the conductive paste can be maintained satisfactorily.

The solvent can be appropriately selected from the viewpoint of solubility and boiling point of the silicone rubber-based curable resin composition. For example, an aliphatic hydrocarbon having 5 or more and 20 or less carbon atoms, preferably 8 or more and 18 or less carbon atoms. It is possible to contain an aliphatic hydrocarbon of the above, more preferably an aliphatic hydrocarbon having 10 or more and 15 or less carbon atoms.

Examples of the solvent include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane and tetradecane; benzene, toluene, ethylbenzene, xylene, mecitylene and tri. Aromatic hydrocarbons such as fluoromethylbenzene and benzotrifluoride; diethyl ether, diisopropyl ether, dibutyl ether, cyclopentylmethyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monobutyl ether, dipropylene Ethers such as glycol dimethyl ether, dipropylene glycol methyl-n-propyl ether, 1,4-dioxane, 1,3-dioxane, tetrahydrofuran; dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1 , 1-Trichloroethane, haloalkanes such as 1,1,2-trichloroethane; carboxylic acid amides such as N, N-dimethylformamide, N, N-dimethylacetamide; Esters and the like can be exemplified. These may be used alone or in combination of two or more.
The solvent used here may be appropriately selected from the solvents capable of uniformly dissolving or dispersing the composition components in the above conductive paste.

The upper limit of the polarity term (δ _p ) of the Hansen solubility parameter of the solvent is, for example, 10 MPa ^1/2 or less, preferably 7 MPa ^1/2 or less, and more preferably 5.5 MPa ^1/2 or less. It can contain a first solvent. This makes it possible to improve the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste. The lower limit of the polarity term (δ _p ) of the first solvent is not particularly limited, but may be, for example, 0 Pa ^1/2 or more.

The upper limit of the hydrogen bond term (δ _h ) of the Hansen solubility parameter in the first solvent is, for example, 20 MPa ^1/2 or less, preferably 10 MPa ^1/2 or less, and more preferably 7 MPa ^1/2 or less. be. This makes it possible to improve the dispersibility and solubility of the silicone rubber-based curable resin composition in the paste. The lower limit of the hydrogen bond term (δ _h ) of the first solvent is not particularly limited, but may be, for example, 0 Pa ^1/2 or more.

The Hansen solubility parameter (HSP) is an index of the solubility of a substance in another substance. HSP represents solubility as a three-dimensional vector. This three-dimensional vector can be typically represented by a dispersion term (δ _d ), a polarity term (δ _p ), and a hydrogen bond term (δ _h ). And it can be judged that those having similar vectors have high solubility. It is possible to judge the similarity of the vector by the distance (HSP distance) of the Hansen solubility parameter.

The Hansen solubility parameter (HSP value) used in the present specification can be calculated using software called HSPiP (Hansen Solubility Parameter in Practice). Here, the computer software HSPiP developed by Hansen and Abbott includes a function for calculating the HSP distance and a database describing various resin and solvent or non-solvent Hansen parameters.
The solubility of each resin in a pure solvent and a mixed solvent of a good solvent and a poor solvent was investigated, and the results were input to the HSPiP software. Is calculated.

As the solvent of the present embodiment, for example, an elastomer or a solvent having a small difference in HSP distance, polarity term and hydrogen bond term between the constituent unit constituting the elastomer and the solvent can be selected.

The lower limit of the viscosity of the conductive paste and / or the insulating paste when measured at a room temperature of 25 ° C. and a shear rate of 20 [1 / s] is, for example, 1 Pa · s or more, preferably 5 Pa · s or more. , More preferably 10 Pa · s or more. Thereby, the film forming property can be improved. In addition, the shape retention can be improved even when a thick film is formed. On the other hand, the upper limit of the viscosity of the conductive paste and / or the insulating paste at room temperature of 25 ° C. is, for example, 100 Pa · s or less, preferably 90 Pa · s or less, and more preferably 80 Pa · s or less. .. Thereby, the printability in the paste can be improved.

At room temperature 25 ° C., the viscosity when measured at a shear rate of 1 [1 / s] is η1, the viscosity when measured at a shear rate of 5 [1 / s] is η5, and the viscosity index is the viscosity ratio (η1 / η5). ).
At this time, the lower limit of the thixotropic index of the conductive paste and / or the insulating paste is, for example, 1.0 or more, preferably 1.1 or more, and more preferably 1.2 or more. As a result, the shape of the wiring obtained by the printing method can be stably maintained. On the other hand, the upper limit of the thixotropic index of the conductive paste and / or the insulating paste is, for example, 3.0 or less, preferably 2.5 or less, and more preferably 2.0 or less. This makes it possible to improve the printability of the paste.

The content of the silicone rubber-based curable composition in the insulating paste is preferably 10% by mass or more, more preferably 15% by mass or more, and 20% by mass or more in 100% by mass of the insulating paste. Is more preferable. The content of the silicone rubber-based curable composition in the insulating paste is preferably 50% by mass or less, more preferably 40% by mass or less, and 35% by mass in 100% by mass of the insulating paste. It is more preferably% or less.

(Conductive filler)
As the conductive filler, a known conductive material may be used, but metal powder (G) may be used.
The metal constituting the metal powder (G) is not particularly limited, but for example, copper, silver, gold, nickel, tin, lead, zinc, bismuth, antimon, or at least one kind of metal powder obtained by alloying these. Alternatively, two or more of these can be included.
Of these, the metal powder (G) preferably contains silver or copper, that is, silver powder or copper powder, because of its high conductivity and high availability.
As these metal powders (G), those coated with other kinds of metals can also be used.

In the present embodiment, the shape of the metal powder (G) is not limited, but conventionally used metal powders (G) such as dendritic, spherical, and lint-like can be used. Among these, phosphorus flake-shaped metal powder (G) may be used.

Further, the particle size of the metal powder (G) is not limited, but for example, the average particle size _D50 is preferably 0.001 μm or more, more preferably 0.01 μm or more, still more preferably 0.1 μm or more. be. The particle size of the metal powder (G) is, for example, preferably 1,000 μm or less, more preferably 100 μm or less, and further preferably 20 μm or less with an average particle size _D50 .
By setting the average particle size D ₅₀ in such a range, it is possible to exhibit appropriate conductivity as a silicone rubber.
The particle size of the metal powder (G) is determined by, for example, observing a conductive paste or a silicone rubber formed by using the conductive paste with a transmission electron microscope or the like, performing image analysis, and arbitrarily selecting a metal. It can be defined as the average value of 200 pieces of flour.

The content of the conductive filler in the conductive paste is preferably 30% by mass or more, more preferably 40% by mass or more, and more preferably 50% by mass or more in 100% by mass of the conductive paste. More preferred. The content of the conductive filler in the conductive paste is preferably 85% by mass or less, more preferably 75% by mass or less, and 65% by mass or less in 100% by mass of the conductive paste. Is even more preferable.
By setting the content of the conductive filler to the above lower limit value or more, the silicone rubber can have an appropriate conductive property. Further, by setting the content of the conductive filler to the above upper limit value or less, the silicone rubber can have appropriate flexibility.

The content of the silicone rubber-based curable composition in the conductive paste is preferably 1% by mass or more, more preferably 3% by mass or more, and 5% by mass or more in 100% by mass of the conductive paste. Is more preferable. The content of the silicone rubber-based curable composition in the conductive paste is preferably 25% by mass or less, more preferably 20% by mass or less, and 15% by mass in 100% by mass of the conductive paste. It is more preferably% or less.
By setting the content of the silicone rubber-based curable composition to the above lower limit value or more, the silicone rubber can have appropriate flexibility. Further, by setting the content of the silicone rubber-based curable composition to the above upper limit value or less, the mechanical strength of the silicone rubber can be improved.

The lower limit of the content of the silica particles (C) in the conductive paste is, for example, 1% by mass or more, preferably 3% by mass or more, based on 100% by mass of the total amount of the silica particles (C) and the conductive filler. It is more preferably 5% by mass or more. Thereby, the mechanical strength of the silicone rubber can be improved. On the other hand, the upper limit of the content of the silica particles (C) in the conductive paste is preferably 20% by mass or less in the total amount of 100% by mass of the silica particles (C) and the conductive filler. Is 15% by mass or less, more preferably 10% by mass or less. This makes it possible to balance the elastic electrical characteristics and the mechanical strength of the silicone rubber.

The content of the conductive filler in the conductive cured product obtained by curing the conductive paste constituting the wiring such as the lower wiring and the upper wiring is preferably 65% by mass or more in 100% by mass of the conductive cured product. It is more preferably 70% by mass or more, and further preferably 75% by mass or more. The content of the conductive filler in the conductive cured product is preferably 95% by mass or less, more preferably 90% by mass or less, and 85% by mass or less in 100% by mass of the conductive cured product. Is more preferable.
By setting the content of the conductive filler to the above lower limit value or more, the silicone rubber can have an appropriate conductive property. Further, by setting the content of the conductive filler to the above upper limit value or less, the silicone rubber can have appropriate flexibility.

Next, the manufacturing process of the stretchable multilayer circuit board 100 of the present embodiment will be described.

The method for manufacturing a stretchable multilayer circuit board of the present embodiment is a method for manufacturing a flexible circuit board having a multilayer wiring structure, which includes a step of forming a substrate and a step of forming a plurality of lower wirings on the substrate. , A step of forming a lower insulating layer on the lower wiring, a step of forming a plurality of upper wirings on the lower insulating layer, and a step of forming an upper insulating layer on the upper wiring.
In the method for manufacturing a stretchable multilayer circuit board, the substrate, the lower wiring, the lower insulating layer, the upper wiring, and the upper insulating layer are each formed by using a thermosetting elastomer and viewed in a direction perpendicular to one surface of the substrate. At that time, the lower wiring and the upper wiring are formed so that the first upper wiring intersects with at least the first lower wiring but can be electrically connected to each other.

In the method for manufacturing a stretchable multilayer circuit board, a plurality of lower wirings and a plurality of upper wirings may be formed by applying the same or different conductive pastes and drying them.

Here, an example of the manufacturing process of the stretchable multilayer circuit board 100 will be described with reference to FIG.
FIG. 3 is a cross-sectional view showing an outline of a manufacturing process of the stretchable multilayer circuit board 100.

First, as shown in FIG. 3A, the support 120 is installed on the workbench 11, and the insulating paste 13 is applied onto the support 12. As the coating method, various methods can be used, and for example, a printing method such as a squeegee method using the squeegee 14 can be used. Subsequently, the coating-like insulating paste 13 can be dried to form an insulating layer 32 (a substrate 110 made of an insulating elastomer) on the support 12. The drying conditions can be appropriately set according to the type and amount of the solvent in the insulating paste 13, and for example, the drying temperature may be 150 ° C. to 180 ° C., the drying time may be 1 minute to 30 minutes, or the like. can.

The insulating layer 32 constituting the substrate 110 may be formed by a molding method such as calendar molding or compression molding using the above-mentioned silicone rubber-based curable composition.

Subsequently, as shown in FIG. 3B, a mask 16 having a predetermined opening pattern shape is arranged on the insulating layer 32. Then, as shown in FIGS. 3 (b) and 3 (c), the conductive paste 15 is applied onto the insulating layer 32 via the mask 16.
As the coating method, the same method as the coating method of the insulating paste 13 can be used, and for example, squeegee printing with the squeegee 14 may be used.
Here, when the insulating paste 13 and the conductive paste 15 each contain a silicone rubber-based curable composition, a conductive coating film (conductive layer 52) having a predetermined pattern shape is laminated on the dried insulating layer 32. After that, these may be collectively cured. The curing treatment can be appropriately set depending on the silicone rubber-based curable composition, and for example, the curing temperature can be 160 ° C. to 220 ° C., the curing time can be 1 hour to 3 hours, or the like. As shown in FIG. 3D, the mask 16 can be removed after the curing treatment or before the curing treatment. As a result, the cured product of the conductive layer 52 (lower wiring 120 composed of the conductive elastomer) having a predetermined pattern shape can be formed on the substrate composed of the cured product of the insulating layer 32.

Subsequently, as shown in FIG. 3 (e), the insulating paste 17 is further coated on the insulating layer 32 and the patterned conductive layer 52, and the insulating layer 72 (as shown in FIG. 3 (f)). A lower insulating layer 130) made of an insulating elastomer can be formed.
After that, the steps of FIGS. 3 (b) to 3 (e) may be repeated as appropriate. As a result, the upper wiring 150 made of a conductive elastomer, the upper insulating layer 160 made of an insulating elastomer, and the like are formed, and the circuit can be multi-layered. Further, by adjusting the mask pattern and its arrangement position, an intersecting structure of the lower wiring 120 and the upper wiring 150 can be formed.
The repeating step may be performed after separating the support 120 from the insulating layer 32.
As a result, the stretchable multilayer circuit board 100 shown in FIG. 1A can be obtained.

Thus, in the stretchable multilayer circuit board 100, at least one of the substrate 110, the lower insulating layer 130, and the upper insulating layer 160 is preferably an insulating printed layer all printed with an insulating paste. It may be configured. This makes it possible to improve the adhesion with the wiring.

In the stretchable multilayer circuit board 100, the lower wiring 120 and the upper wiring 150 may each be composed of a conductive printed layer printed with a conductive paste. This makes it possible to freely select the pattern shape of the conductive print layer.

The lower limit of the content of the conductive filler of at least one of the lower wiring 120 and the upper wiring 150 is, for example, 70% by mass or more, preferably 75% by mass or more, and more preferably 80% by mass or more in 100% by mass of the wiring. be. As a result, the stretchable electrical characteristics of the stretchable multilayer circuit board can be enhanced. On the other hand, the upper limit of the content of at least one of the conductive fillers of the lower wiring 120 and the upper wiring 150 is, for example, 90% by mass or less, preferably 88% by mass or less, and more preferably 85% by mass in 100% by mass of the wiring. It is as follows. This makes it possible to suppress deterioration of rubber characteristics such as elasticity of the stretchable multilayer circuit board.

Hereinafter, the characteristics of the stretchable multilayer circuit board 100 will be described.

In the present embodiment, at least one or more of the substrate 110, the lower wiring 120, the lower insulating layer 130, the upper wiring 150, and the upper insulating layer 160 may be made of an elastomer having at least one of the following characteristics. In one preferred embodiment, the substrate 110 is composed of an elastomer having at least one of the following tear strength, elongation at break, and durometer hardness A:

The lower limit of the tear strength of the elastomer is, for example, 25 N / mm or more, preferably 28 N / mm or more, more preferably 30 N / mm or more, still more preferably 33 N / mm or more, still more preferably 35 N / mm or more. This makes it possible to improve the durability of the elastomer during repeated use. In addition, the mechanical strength of the elastomer can be improved.
On the other hand, the upper limit of the tear strength of the elastomer is not particularly limited, but may be, for example, 80 N / mm or less, or 70 N / mm or less. This makes it possible to balance various properties of the elastomer.

The lower limit of the tensile strength of the elastomer is, for example, 5.0 MPa or more, preferably 10.0 MPa or more, and more preferably 12.0 MPa or more. This makes it possible to improve the mechanical strength of the elastomer. In addition, it is possible to realize an elastomer having excellent durability that can withstand repeated deformation.
On the other hand, the upper limit of the tensile strength of the elastomer is not particularly limited, but may be, for example, 25 MPa or less, or 20 MPa or less. This makes it possible to balance various properties of the elastomer.

The lower limit of the elongation at break of the elastomer is, for example, 100% or more, preferably 200% or more, more preferably 300% or more, still more preferably 400% or more. This makes it possible to improve the high elasticity and durability of the elastomer.
On the other hand, the upper limit of the elongation at break of the elastomer is not particularly limited, but may be, for example, 2000% or less, or 1500% or less. This makes it possible to balance various properties of the elastomer.

The upper limit of the durometer hardness A of the elastomer is not particularly limited, but may be, for example, 90 or less, preferably 75 or less, and more preferably 70 or less. This makes it possible to balance the cured physical properties of the silicone rubber. As a result, it is possible to enhance the deformability of the elastomer, which facilitates deformation such as bending and stretching.
On the other hand, the lower limit of the durometer hardness A of the elastomer is not particularly limited, but is, for example, 30 or more, preferably 35 or more, and more preferably 40 or more. As a result, the mechanical strength of the elastomer can be increased.

In the present embodiment, for example, the following method can be adopted as a method for measuring the characteristics of each member of the stretchable multilayer circuit board and the characteristics of the elastomer used for each member. For the measurement of the characteristics of each member, each member such as a substrate may be used as it is as a test piece.

(Measurement conditions for tear strength)
A crescent-shaped test piece is prepared using an elastomer, and the tear strength of the obtained crescent-shaped test piece is measured at 25 ° C. in accordance with JIS K6252 (2001).

(Measurement conditions for tensile strength)
A dumbbell-shaped No. 3 test piece is prepared using an elastomer, and the tensile strength of the obtained dumbbell-shaped No. 3 test piece is measured at 25 ° C. in accordance with JIS K6251 (2004).

(Measurement conditions for breaking elongation)
A dumbbell-shaped No. 3 test piece is prepared using an elastomer, and the obtained dumbbell-shaped No. 3 test piece is measured for elongation at break in accordance with JIS K6251 (2004) at 25 ° C.

(Measurement procedure of durometer hardness A)
A sheet-shaped test piece is prepared using an elastomer, and the durometer hardness A of the obtained sheet-shaped test piece at 25 ° C. is measured according to JIS K6253 (1997).

At 25 ° C., the volume resistivity of at least one of the first lower wiring 120 and the first upper wiring 150 when unstretched is, for example, 1 × 10 ^-5 Ω · cm or more and 1 × 10 ^-1 Ω · cm or less. It is preferably 5 × 10 ⁻⁵ Ω · cm or more and 5 × 10 − ² Ω · cm or less, and more preferably 1 × 10 ^-4 Ω · cm or more and 1 × 10 − ² Ω · cm or less. Within such a range, the stretchable multilayer circuit board 100 having excellent electrical characteristics can be obtained even when it is not stretched and even when it is stretched.

At least one of the electric resistance values of the first lower wiring 120 and the first upper wiring 150 at 25 ° C. when unstretched is, for example, 0.01 Ω / cm or more and 1000 Ω / cm or less, preferably 0.05 Ω / cm or more. It is 500 Ω / cm or less, more preferably 0.1 Ω / cm or more and 200 Ω / cm or less.

When the electrical resistance value at 25 ° C. and unstretched is within the above range, at least one of the electrical resistance values of the first lower wiring 120 and the first upper wiring 150 at 25 ° C. and 50% elongation is 0.1Ω. It is / cm or more and 1200 Ω / cm or less, preferably 0.2 Ω / cm or more and 700 Ω / cm or less, and more preferably 0.3 Ω / cm or more and 300 Ω / cm or less. Within such a range, the stretchable multilayer circuit board 100 having excellent electrical characteristics can be obtained even when it is not stretched and even when it is stretched.

Let X1 be the electrical resistance value of the wiring at 25 ° C. and 20% elongation, and X2 be the electrical resistance value of the wiring at 25 ° C. and 50% elongation.
When the electric resistance value at 25 ° C. and unstretched is within the above range, at least one of the first lower wiring 120 and the first upper wiring 150 is, for example, 1.2 ≦ X2 / X1 ≦ 8.0, preferably. Is configured to satisfy 1.3 ≦ X2 / X1 ≦ 7.0, more preferably 1.4 ≦ X2 / X1 ≦ 6.0. Within such a range, the stretchable multilayer circuit board 100 having excellent electrical characteristics can be obtained even at the time of extension.

Let Z1 be the electrical resistance value of the wiring at 25 ° C. and unstretched, and let Z2 be the electrical resistance value of the wiring in the unstretched state after performing the stretching operation at 25 ° C. and 50% 100 times.
At least one of the first lower wiring 120 and the first upper wiring 150 is, for example, 1.1 ≦ Z2 / Z1 ≦ 3.0, preferably 1.2 ≦ Z2 / Z1 ≦ 2.9, more preferably 1. It is configured to satisfy .3 ≦ Z2 / Z1 ≦ 2.8. Within such a range, the stretchable multilayer circuit board 100 having excellent electrical characteristics can be obtained even during repeated stretching.

The electronic device of this embodiment includes the above-mentioned stretchable multilayer circuit board.
Examples of the electronic device include a stretchable display, a wearable device, a biosensor, and the like.

Hereinafter, an example in which the stretchable multilayer circuit board is applied to the stretchable display will be described with reference to FIG.
FIG. 4 is a functional block diagram showing an example of the configuration of a display device including a stretchable display.

An example of the display device 300 includes a display unit 310 and a control unit 320. The display device 300 may further include at least one or more other functional units such as a power supply unit 350 and a communication unit 340.

The display unit 310 includes a stretchable display (display unit 310), and displays by the stretchable display. The stretchable display is composed of the above-mentioned stretchable multilayer circuit board on which a display element or the like is mounted.
Such a display device 300 can be attached to an object according to various uses such as clothes and a body.

The control unit 320 controls the display content of the display unit 310. The display unit 310 can control the display content based on the information input from the input unit 330, for example.

The input unit 330 may be provided directly on the display device 300, or may be provided on an external terminal such as a smartphone. The information input from the input unit 330 is transmitted to the control unit 320 via the communication unit 340 included in the display device 300. The input unit 330 may be composed of, for example, a button or a touch panel.
When the external terminal is provided with a display, the same display content as that of the display unit 310 may be displayed on the display via the communication unit 340.
The communication unit 340 includes various communication means such as Bluetooth (registered trademark) and Wi-Fi.

The display device 300 may further include a storage unit 360. The control unit 320 may display the display content stored in the storage unit 360 on the display unit 310. Further, the control unit 320 can generate, change, and delete the information constituting the display contents stored in the storage unit 360.

The power supply unit 350 may be composed of a mobile battery or may include an electrode that can be connected to an external power source.

In the display device 300, even if a non-display area around the display area is provided on the substrate 110 of the stretchable multilayer circuit board constituting the display unit 310 in addition to the display area on which the display element is mounted. good. On the substrate 110 in the non-display area, for example, at least one or two or more of each unit such as a control unit 320, a power supply unit 350, an input unit 330, a communication unit 340, and a storage unit 360 may be provided. As a result, the display element and each part or between each part can be connected by elastic wiring.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like to the extent that the object of the present invention can be achieved are included in the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the description of these Examples.

(Vinyl group-containing organopolysiloxane (A))
(A1-1): First vinyl group-containing linear organopolysiloxane: Vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 1 (structure represented by the above formula (1-1)).
(A1-2): Second vinyl group-containing linear organopolysiloxane: Vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 2 ( ^R1 and R having a structure represented by the above formula (1-1)). Structure in which ² is a vinyl group)

(Organohydrogenpolysiloxane (B))
(B-1): Organohydrogenpolysiloxane: "TC-25D" manufactured by Momentive Co., Ltd.

(Silica particles (C))
(C): Silica fine particles (particle size 7 nm, specific surface area 300 m ² / g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL300"

(Silane Coupling Agent (D))
(D-1): Hexamethyldisilazane (HMDZ), manufactured by Gelest, "HEXAMETHYLDISILAZANE (SIH6110.1)".
(D-2) Divinyltetramethyldisilazane, manufactured by Gelest, "1,3-DIVINYLTRAMETHYLDISILAZANE (SID4612.0)"

(Platinum or platinum compound (E))
(E-1): Platinum compound (manufactured by Momentive, trade name "TC-25A")

(Water (F))
(F): Pure water

(Metal powder (G))
(G1): Silver powder, manufactured by Tokuriki Kagaku Kenkyusho, trade name "TC-101", median diameter d ₅₀ : 8.0 μm, aspect ratio 16.4, average major axis 4.6 μm

(Synthesis of vinyl group-containing organopolysiloxane (A))
[Synthesis scheme 1: Synthesis of first vinyl group-containing linear organopolysiloxane (A1-1)]
The first vinyl group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (5).
That is, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium silicate were placed in a 300 mL separable flask having a cooling tube and a stirring blade substituted with Ar gas, heated, and heated at 120 ° C. for 30 minutes. Stirred. At this time, an increase in viscosity was confirmed.
Then, the temperature was raised to 155 ° C., and stirring was continued for 3 hours. Then, after 3 hours, 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added, and the mixture was further stirred at 155 ° C. for 4 hours.
After 4 hours, it was diluted with 250 mL of toluene and then washed 3 times with water. The organic layer after washing was washed with 1.5 L of methanol several times for reprecipitation purification, and the oligomer and the polymer were separated. The obtained polymer was dried under reduced pressure at 60 ° C. overnight to obtain a first vinyl group-containing linear organopolysiloxane (A1-1) ⁽ Mn = 2,2 × 105, Mw = 4.8 ×). 10 ⁵ ). The vinyl group content calculated by 1 H-NMR spectrum measurement was 0.04 mol%.

[Synthesis scheme 2: Synthesis of second vinyl group-containing linear organopolysiloxane (A1-2)]
In the above synthesis step (A1-1), in addition to 74.7 g (252 mmol) of octamethylcyclotetrasiloxane, 2,4,6,8-tetramethyl 2,4,6,8-tetravinylcyclotetrasiloxane 0. By performing the same as the synthesis step of (A1-1) except that 86 g (2.5 mmol) was used, a second vinyl group-containing linear organopolysiloxane (as shown in the following formula (6)) ( A1-2) was synthesized. The vinyl group content calculated by 1 H-NMR spectrum measurement was 0.92 mol%.

(Preparation of silicone rubber-based curable composition)
Silicone rubber-based curable compositions 1 to 5 were prepared according to the following procedure.
First, a mixture of 90% vinyl group-containing organopolysiloxane (A), silane coupling agent (D) and water (F) is kneaded in advance at the ratio shown in Table 1 below, and then silica particles (silica particles ()) are added to the mixture. C) was added and further kneaded to obtain a kneaded product (silicone rubber compound).
Here, the kneading after the addition of the silica particles (C) is carried out in the first step of kneading under a nitrogen atmosphere at 60 to 90 ° C. for 1 hour for the coupling reaction, and the removal of the by-product (ammonia). Therefore, it is carried out by going through the second step of kneading under a reduced pressure atmosphere under the condition of 160 to 180 ° C. for 2 hours, and then cooling, and the remaining 10% of the vinyl group-containing organopolysiloxane (A) is added twice. It was added separately and kneaded for 20 minutes.
Subsequently, organohydrogenpolysiloxane (B), platinum or platinum compound (E) was added to 100 parts by weight of the obtained kneaded product (silicone rubber compound) at the ratio shown in Table 2 below, and kneaded with a roll. Then, silicone rubber-based curable compositions 1 to 5 were obtained.

(Preparation of insulating paste)
The obtained 32 parts by weight of the silicone rubber-based curable composition 4 was immersed in 68 parts by weight of tetradecane (solvent), and then stirred with a rotation / revolution mixer to obtain a conductive paste.

(Preparation of conductive paste)
The obtained 13.7 parts by weight of the silicone rubber-based curable composition 5 was immersed in 31.8 parts by weight of tetradecane (solvent), and then stirred with a rotation / revolution mixer to 54.5 parts by weight of the metal. After adding the powder (G1), the mixture was kneaded with three rolls to obtain a conductive paste.

<Example 1>
(Manufacturing of elastic circuit board)
The stretchable multilayer circuit board 100 shown in FIG. 5 was manufactured according to the following procedure.
First, the obtained silicone rubber-based curable composition 1 was pressed at 170 ° C. and 10 MPa for 10 minutes to form a sheet and first cured. Subsequently, it was secondarily cured at 200 ° C. for 4 hours to obtain a substrate 110 (cured product of silicone rubber-based curable composition) having the substrate thickness of length × width × thickness: 12 cm × 12 cm × Table 3.
Using the obtained conductive paste, eight lower wiring patterns were drawn on the substrate 110 through a mask having a predetermined pattern, and dried at 140 ° C. for 20 minutes. No. The lower wirings 120 of 1 to 8 each have a structure in which the vertical wirings and the horizontal wirings having the lengths shown in Table 2 are connected by changing the direction by 90 degrees in this order, and the width of each wiring is 1.0 mm. The thickness is the wiring thickness in Table 3.
Using the obtained insulating paste, an insulating layer is formed on the substrate 110 and the lower wiring 120 via a mask having a predetermined pattern, and dried at 140 ° C. for 20 minutes to insulate in Table 3. The lower insulating layer 130 having a layer thickness was formed. However, an opening is formed in the lower insulating layer 130 so that the lower connecting portion 122 and the lower connecting portion 124 of the eight lower wirings 120 are exposed.
Using the obtained conductive paste, eight upper wiring patterns having wirings intersecting the eight lower wirings 120 at 90 degrees in a top view through a mask having a predetermined pattern are placed on the lower insulating layer 130. And dried at 140 ° C. for 20 minutes. No. The upper wiring 150 of 9 to 16 has a structure in which the vertical wiring (long), the horizontal wiring, and the vertical wiring (short) having the lengths shown in Table 2 are connected in this order by changing the direction by 90 degrees. The width of each wiring was 1.0 mm, and the thickness was the wiring thickness shown in Table 3.
Further, in each of the vertical wirings (short) of the eight upper wirings 150, an upper connecting portion 152 having a wiring width of 1.0 mm and a thickness of the wiring thickness shown in Table 3 is provided in the vicinity of the lower connecting portion 122. This was formed.
Using the obtained insulating paste, an insulating layer is formed on the substrate 110, the lower insulating layer 130, and the upper wiring 150 via a mask having a predetermined pattern, and dried at 140 ° C. for 20 minutes. The upper insulating layer 160 having the insulating layer thickness shown in Table 3 was formed. However, the lower connecting portion 122 and the lower connecting portion 124 of the eight lower wirings 120 are exposed to the upper insulating layer 160, and the upper connecting portion 152 and the upper connecting portion 154 of the eight upper wirings 150 are exposed. An opening was formed in.
The multilayer structure having the substrate 110, the lower wiring 120, the lower insulating layer 130, the upper wiring 150, and the upper insulating layer 160 was cured at 180 ° C. for 2 hours, and the stretchable multilayer structure of Example 1 shown in FIG. 5 was cured. The circuit board 100 was obtained.

<Examples 2 and 3>
Except for changing the silicone rubber-based curable composition 1 constituting the substrate to the silicone rubber-based curable composition 2 or 3 in Table 1 and adopting the substrate thickness, the insulating layer thickness, and the wiring thickness in Table 3. The elastic multilayer circuit board 100 of Examples 2 and 3 was produced in the same manner as in Example 1.
In the cross section of the stretchable multilayer circuit board 100 in the stacking direction, the substrate thickness, the insulating layer thickness, and the wiring thickness were measured using a microscope.

(Manufacturing of electronic device)
In the obtained stretchable multilayer circuit board 100 of FIG. 5, No. The lower connection portion 122 and No. 2 in the lower wiring 120 of 1 to 9. LED chips (electronic components 170) were placed on each of the 64 locations straddling the upper connection portion 152 in the upper wiring 150 of 10 to 16, and these were adhered with the above conductive paste, dried and cured at 140 ° C. for 20 minutes. .. Then, the LED chip was sealed with the above insulating paste, dried at 140 ° C. for 20 minutes, and cured to obtain an electronic device.

The following items were evaluated for the obtained stretchable multilayer circuit board and the electronic device.

(hardness)
The silicone rubber-based curable compositions of Examples 1 to 3 were pressed at 170 ° C. and 10 MPa for 10 minutes to form a sheet and primary cured. Subsequently, it was secondarily cured at 200 ° C. for 4 hours, and a sheet-shaped substrate (cured product of a silicone rubber-based curable composition) having the substrate thickness shown in Table 3 was used as a test piece.
The test pieces were laminated so as to have a thickness of 6 mm, and the durometer hardness A of the obtained sheet-shaped test pieces at 25 ° C. was measured according to JIS K6253 (1997).

(Tear strength)
Using the above test piece, the tear strength at 25 ° C. was measured according to JIS K6252 (2001). The unit is N / mm.

(Tensile strength)
Using the above test piece, the tensile strength at 25 ° C. was measured according to JIS K6251 (2004). The unit is MPa.

Using the above test piece, the elongation at break was measured according to JIS K6251 (2004). The breaking elongation was calculated by [moving distance between chucks (mm)] ÷ [initial distance between chucks (35 mm)] × 100. The unit is%.

(Connection reliability)
The test piece (sheet-like substrate) obtained by using the silicone rubber-based curable composition of Examples 1 to 3 was further heat-treated at 180 ° C. for 2 hours. The dimensional change of the test piece before and after this heat treatment was about 0%.

(Electrical characteristics)
A voltage of 5 V was applied to the obtained electronic device via each lower wiring 120 and each upper wiring 150, and it was confirmed that 64 LED chips emitted light all at once. The case where there are 5% or more of all the LEDs with poor connection (non-light emission) is evaluated as ×, and the case where the number is less than 5% is evaluated as ○, and the results are shown in Table 1.

In the cured product (wiring pattern) of the conductive paste used for the lower wiring 120 and the upper wiring 150, the volume resistance value at 25 ° C. and unstretched is 3.2 × 10 ^-4 Ω · cm, 25 ° C., unstretched. The electrical resistance value at that time was 1.4 Ω / cm.

(Expandable electrical characteristics)
The stretchable multilayer circuit board 100 in the obtained electronic device was repeatedly stretched by 20% in the vertical direction of FIG. 5 10 times. In the electronic device after the expansion / contraction operation, a voltage was applied in the same manner as the above electrical characteristics, and it was confirmed that the 64 LED chips emitted light all at once. The case where there are 5% or more of all the LEDs with poor connection (non-light emission) is evaluated as ×, and the case where the number is less than 5% is evaluated as ○, and the results are shown in Table 1.

(Expandable durability)
As a result of observing the cross-sectional view cut in the thickness direction of the stretchable multilayer circuit board 100 after the expansion / contraction operation, the adhesion interface of the substrate 110, the lower wiring 120, the lower insulating layer 130, the upper wiring 150, and the upper insulating layer 160, respectively. It was confirmed that no peeling occurred.

Examples 1 to 3 show the results of obtaining a stretchable multilayer circuit board having a structure in which a plurality of electronic components (LEDs) are highly integrated and having excellent stretchable electrical characteristics.

11 Worktable 12 Support 13 Insulation paste 14 Squeegee 15 Conductive paste 16 Mask 17 Insulation paste 32 Insulation layer 52 Conductive layer 72 Insulation layer 100 Elastic multi-layer circuit board 110 Board 120 Lower wiring 120 Support 122 Lower connection part 124 Lower Connection 126 Lower Wiring 130 Lower Insulation Layer 140 Opening 142 Opening 150 Top Wiring 152 Top Connection 154 Top Connection 156 Top Wiring 160 Top Insulation Layer 170 Electronic Components 200 Multilayer Wiring Structure 210 Crossed Structure 220 Connection Structure

Claims (30)

With the board
With a plurality of lower wirings provided on the board,
The lower insulating layer provided on the lower wiring and
A plurality of upper wirings provided on the lower insulating layer, and
An elastic multilayer circuit board comprising a multilayer wiring structure having an upper insulating layer provided on the upper wiring.
The substrate, the lower wiring, the lower insulating layer, the upper wiring, and the upper insulating layer each contain a thermosetting elastomer.
In the multilayer wiring structure,
An intersecting structure in which the first lower wiring and the first upper wiring intersect each other when viewed in a direction perpendicular to one surface of the substrate.
A connection structure in which the first lower wiring and the first upper wiring can be electrically connected to each other,
A stretchable multilayer circuit board. The stretchable multilayer circuit board according to claim 1.
An elastic multilayer circuit board in which the substrate, the lower insulating layer, and the upper insulating layer each contain silicone rubber. The stretchable multilayer circuit board according to claim 1 or 2.
An elastic multilayer circuit board in which the lower wiring and the upper wiring contain silicone rubber and a conductive filler, respectively. The stretchable multilayer circuit board according to any one of claims 1 to 3.
A stretchable multilayer circuit board in which the substrate, the lower wiring, the lower insulating layer, the upper wiring, and the upper insulating layer contain the same type of silicone rubber. The stretchable multilayer circuit board according to claim 3.
A stretchable multilayer circuit board in which the conductive filler contains silver powder. The stretchable multilayer circuit board according to any one of claims 1 to 5.
A stretchable multilayer circuit board in which at least one of the substrate, the lower insulating layer, and the upper insulating layer contains an inorganic filler. The stretchable multilayer circuit board according to any one of claims 1 to 6.
An elastic multilayer circuit board in which at least one of the lower wiring and the upper wiring contains an inorganic filler. The stretchable multilayer circuit board according to claim 6 or 7.
A stretchable multilayer circuit board in which the inorganic filler contains silica. The stretchable multilayer circuit board according to any one of claims 1 to 8.
A stretchable multilayer circuit board in which at least one of the substrate, the lower insulating layer, and the upper insulating layer is composed of an insulating printed layer printed with an insulating paste. The stretchable multilayer circuit board according to any one of claims 1 to 9.
An elastic multilayer circuit board in which the lower wiring and the upper wiring are each composed of a conductive printed layer printed with a conductive paste. The stretchable multilayer circuit board according to any one of claims 1 to 10.
A stretchable multilayer circuit board having a tear strength of 25 N / mm or more at 25 ° C., which is measured according to JIS K6252 (2001). The stretchable multilayer circuit board according to any one of claims 1 to 11.
A stretchable multilayer circuit board having a breaking elongation of the substrate at 25 ° C. of 100% or more, which is measured according to JIS K6251 (2004). The stretchable multilayer circuit board according to any one of claims 1 to 12.
A stretchable multilayer circuit board having a durometer hardness A of the substrate at 25 ° C. of 30 or more and 90 or less, which is defined in accordance with JIS K6253 (1997). The stretchable multilayer circuit board according to any one of claims 1 to 13.
A stretchable multilayer circuit board having a thickness of the lower insulating layer / a thickness of the substrate of 0.01 or more and 2.0 or less. The stretchable multilayer circuit board according to any one of claims 1 to 14.
A stretchable multilayer circuit board in which the thickness of the lower wiring / the thickness of the lower insulating layer is 0.05 or more and 20.0 or less. The stretchable multilayer circuit board according to any one of claims 1 to 15.
Elastic multilayer having a volume resistivity of 1 × 10 ^-5 Ω · cm or more and 1 × 10 ^-1 Ω · cm or less at 25 ° C. and the first lower wiring and the first upper wiring when unstretched. Circuit board. The stretchable multilayer circuit board according to any one of claims 1 to 16.
When the electrical resistance values of the first lower wiring and the first upper wiring at 25 ° C. and not extended are within the range of 0.01 Ω / cm or more and 1000 Ω / cm or less, the first when extended by 20%. When the electrical resistance values of the lower wiring and the first upper wiring are X1, and the electrical resistance values of the first lower wiring and the first upper wiring at the time of 50% extension are X2, X2 / X1 is A stretchable multilayer circuit board having a value of 1.2 or more and 8.0 or less. The stretchable multilayer circuit board according to any one of claims 1 to 17.
When the electrical resistance values of the first lower wiring and the first upper wiring at 25 ° C. and not extended are within the range of 0.01 Ω / cm or more and 1000 Ω / cm or less, the first when extended by 50%. A stretchable multilayer circuit board in which the electrical resistance values of the lower wiring and the first upper wiring are 0.1 Ω / cm or more and 1200 Ω / cm or less. The stretchable multilayer circuit board according to any one of claims 1 to 18.
Z1 of the electric resistance value of the first lower wiring in the unstretched state at 25 ° C., and Z2 as the electric resistance value of the first lower wiring in the unstretched state after performing the stretching operation of 50% 100 times. When you do
A stretchable multilayer circuit board having Z2 / Z1 of 1.1 or more and 3.0 or less. The stretchable multilayer circuit board according to any one of claims 1 to 19.
In the connection structure, a stretchable multilayer circuit board configured such that the first lower wiring and the first upper wiring are electrically connected via electronic components. The stretchable multilayer circuit board according to claim 20.
The electronic component is a stretchable multilayer circuit board configured to be electrically connected to the first lower wiring and the first upper wiring using at least one of a conductive paste and a solder material. The stretchable multilayer circuit board according to claim 20 or 21.
An elastic multilayer circuit board provided with a sealing portion for sealing the electronic component in the multilayer wiring structure. The stretchable multilayer circuit board according to any one of claims 1 to 22.
In the connection structure, at least the lower insulating layer and the lower opening penetrating the upper insulating layer are formed, and at least the upper opening penetrating the upper insulating layer is formed.
The first lower wiring has a lower connection configured to be exposed within the lower opening.
A stretchable multilayer circuit board having an upper connection portion such that the first upper wiring is configured to be exposed in the upper opening. The stretchable multilayer circuit board according to any one of claims 1 to 23.
In a cross-sectional view when the multilayer wiring structure is cut in the stacking direction, the first lower wiring in the connection structure has a protruding connection portion protruding from the substrate toward the lower wiring. substrate. The stretchable multilayer circuit board according to any one of claims 1 to 24.
The substrate is an elastic multilayer circuit board having no wiring on the other surface on the opposite side to the one on which the upper wiring and the lower wiring are provided. The stretchable multilayer circuit board according to any one of claims 1 to 25.
When viewed in a direction perpendicular to one surface of the substrate
In the multi-layer wiring structure, a plurality of crossing structures are provided in which the plurality of the lower wirings and the plurality of the upper wirings intersect with each other.
An elastic multilayer circuit board in which the plurality of intersecting structures are arranged in a grid pattern. A stretchable display, a wearable device, or a biosensor having the stretchable multilayer circuit board according to any one of claims 1 to 26. A display device including a display unit, a control unit, a power supply unit, and / or a communication unit.
A display device in which the display unit includes the stretchable display according to claim 27. The process of forming the substrate and
The process of forming a plurality of lower wirings on the substrate and
The process of forming the lower insulating layer on the lower wiring and
The process of forming a plurality of upper wirings on the lower insulating layer and
A method for manufacturing an elastic multilayer circuit board having a multilayer wiring structure, comprising a step of forming an upper insulating layer on the upper wiring.
The substrate, the lower wiring, the lower insulating layer, the upper wiring, and the upper insulating layer are each formed by using a thermosetting elastomer.
When viewed in a direction perpendicular to one surface of the substrate, the lower wiring so that the first upper wiring intersects with at least the first lower wiring but can be electrically connected to each other. And to form the upper wiring,
A method for manufacturing a stretchable multilayer circuit board. The method for manufacturing an elastic multilayer circuit board according to claim 29.
A method for manufacturing a stretchable multilayer circuit board, wherein the plurality of lower wirings and the plurality of upper wirings are formed by applying the same or different conductive pastes and drying them.

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