JPWO2019187611A1 - Elastic circuit board - Google Patents

Abstract

An object of the present invention is to suppress a decrease in elasticity due to curing of an adhesive layer that adheres a textile layer and a resin layer, and to have sufficient elasticity (for example, 50% modulus of about 1.0 or less). Is to obtain the circuit board of. The circuit board 1 of the present invention is a stretchable base material 100 and includes a textile layer 110, a resin layer 120 covering the textile layer 110, and a plurality of adhesive portions 130a for adhering the textile layer 110 and the resin layer 120. The elastic base material 100 including the adhesive layer 130 is included, and further includes a circuit pattern 10 formed on the resin layer.

Description

The present invention relates to a circuit board having elasticity.

Conventionally, a printed circuit board in which a circuit pattern is printed on an insulating board has been used as a circuit board, which is one of the main components of an electronic device.

Such printed circuit boards include not only flexible substrates having a bendable structure but also stretchable substrates having elasticity.

For example, Patent Document 1 discloses a textile fabric in which a stretchable conductive layer is thermocompression bonded by a hot melt adhesive layer as a structure of a stretchable substrate.

JP-A-2017-101124

However, the present inventors have found that the structure of the stretchable substrate disclosed in Patent Document 1 has a problem that the stretchable substrate is not sufficiently stretchable due to the curing of the hot melt adhesive layer after thermocompression bonding. It was.

Therefore, an object of the present invention is to provide a circuit board having sufficient elasticity (for example, 50% modulus of about 1.0 or less).

The elastic circuit board according to the present invention is
(1) It is an elastic base material and
With the textile layer,
A resin layer covering the textile layer and
An elastic base material including an adhesive layer including a plurality of adhesive portions for adhering the textile layer and the resin layer, and an elastic base material.
(2) The above object is achieved by including a circuit pattern formed on the resin layer.

In the present invention, the plurality of bonded portions may be arranged independently of the circuit pattern.

In the present invention, the distance between the adjacent adhesive portions among the plurality of adhesive portions may be about 0.7 mm to about 2.0 mm.

In the present invention, the ratio of the total area of the plurality of adhesive portions to the area of the resin layer may be about 60% or less.

In the present invention, the circuit board has a 50% modulus of about 1.0 or less, and the 50% modulus may be defined by "50% modulus = load at 50% elongation (MPa)".

In the present invention, the plurality of adhesive portions may be regularly arranged.

In the present invention, the plurality of adhesive portions may be arranged in a staggered pattern.

In the present invention, the staggered arrangement may have an interval of about 0.7 mm to about 2.0 mm in one direction and an interval of about 0.7 mm to about 2.0 mm in the direction orthogonal to the one direction. ..

In the present invention, the area of each of the plurality of bonded portions may be about 0.1 mm ² to about 0.3 mm ² .

In the present invention, the plurality of adhesive portions may have a substantially circular shape.

In the present invention, the thickness of the stretchable base material may be about 0.25 mm to about 1.0 mm.

In the present invention, the thickness of the circuit pattern may be about 0.005 mm to about 0.02 mm.

In the present invention, the circuit pattern may be formed by a conductive composition containing silver.

In the present invention, the conductive composition may further contain a stretchable material.

In the present invention, the resin layer may contain a thermoplastic resin material.

In the present invention, the product may include the circuit board according to any one of claims 1 to 15.

In the present invention, the product may be selected from the group consisting of clothing, shoes, footwear, gloves, toys, in-vehicle seats, healthcare devices, in-vehicle steering and the like.
Furthermore, the present invention includes the following items.
(Item 1)
(1) It is an elastic base material and
With the textile layer,
A resin layer covering the textile layer and
An elastic base material including an adhesive layer including a plurality of adhesive portions for adhering the textile layer and the resin layer, and an elastic base material.
(2) A circuit board including a circuit pattern formed on the resin layer.
It has a peel strength of at least about 180 g / cm or more and a 50% modulus of about 1.0 or less, the 50% modulus being defined by "50% modulus = load at 50% elongation (MPa)". Circuit board.
(Item 2)
The circuit board according to item 1, wherein the plurality of bonded portions are arranged independently of the circuit pattern.
(Item 3)
The circuit board according to item 1 or 2, wherein the distance between the adjacent adhesive portions among the plurality of adhesive portions is about 0.7 mm to about 2.0 mm.
(Item 4)
The circuit board according to any one of items 1 to 3, wherein the ratio of the total area of the plurality of adhesive portions to the area of the resin layer is about 30% to about 60%.
(Item 5)
The circuit board according to any one of items 1 to 4, wherein the area of each of the plurality of bonded portions is about 0.4 mm ² to about 1.8 mm ^2.
(Item 6)
The circuit board according to item 5, wherein the plurality of bonded portions have a substantially circular shape.
(Item 7)
The circuit board according to item 6, wherein the diameter of the bonded portion is about 0.7 mm to about 1.5 mm.
(Item 8)
The circuit board according to any one of items 1 to 7, which has a peel strength of at least about 700 g / cm or more.
(Item 9)
The circuit board according to any one of items 1 to 8, wherein the thickness of the stretchable base material is about 0.25 mm to about 1.0 mm.
(Item 10)
The circuit board according to any one of items 1 to 9, wherein the thickness of the circuit pattern is about 0.005 mm to about 0.02 mm.
(Item 11)
The circuit board according to any one of items 1 to 10, wherein the circuit pattern is formed of a conductive composition containing silver.
(Item 12)
The circuit board according to item 11, wherein the conductive composition further comprises a stretchable material.
(Item 13)
The circuit board according to any one of items 1 to 12, wherein the resin layer contains a thermoplastic resin material.
(Item 14)
A product including the circuit board according to any one of items 1 to 13.
(Item 15)
The product according to item 14, wherein the product is selected from the group consisting of clothing, shoes, footwear, gloves, toys, in-vehicle seats, healthcare devices and in-vehicle steering.

According to the present invention, a circuit board having sufficient elasticity can be obtained.

FIG. 1 is a diagram for explaining the circuit board 1 according to the first embodiment of the present invention, and FIGS. 1 (a) and 1 (b) are perspective views and plan views showing the appearance of the circuit board 1, respectively. Yes, FIG. 1 (c) is a sectional view taken along line Ic-Ic of FIG. 1 (b). 2A and 2B are views schematically showing a detailed structure of the circuit board 1 shown in FIG. 1, FIG. 2A is an enlarged view of an IIa portion of FIG. 1B, and FIG. 2B is an enlarged view. FIG. 2 is a cross-sectional view taken along the line IIb-IIb of FIG. 2A. FIG. 3 is an enlarged perspective view of part III of FIG. 1 (a). FIG. 4 is a diagram for explaining a specific example of the circuit pattern 10 shown in FIG. 1, and FIGS. 4 (a) to 4 (d) are specific examples of meandering wiring patterns (first to fourth). The meander pattern) is shown. FIG. 5 is a diagram for explaining a method of adhering the textile layer 110 to the resin layer 120 in the order of work steps, and FIGS. 5 (a) to 5 (f) show each work process. FIG. 6 is a diagram showing a mask member Ma used for selectively applying an adhesive to the surface of the resin layer 120 shown in FIG. FIG. 7 is a diagram for explaining the elastic base material 100 obtained by adhering the resin layer 120 to the textile layer 110, and FIG. 7A is a diagram showing the surface of the resin layer 120 of the elastic base material 100. 7 (b) is a photograph showing the side surface of the stretchable base material 100. FIG. 8 is a diagram for explaining the stretchable base material 100 shown in FIG. 7, and FIG. 8 (a) shows a side surface of the stretchable base material 100 that is orthogonal to the side surface shown in FIG. 7 (b). The photograph shown in FIG. 8 (b) is an enlarged photograph of the side surface shown in FIG. 8 (a). FIG. 9 is a diagram for explaining a method of forming the circuit pattern 10 on the resin layer 120 of the elastic base material 100 shown in FIG. 7A in the order of work steps, and FIGS. 9A to 9C. ) Indicates each work process. 10A and 10B are views for explaining the screen printing machine P used for forming the circuit pattern 10, FIG. 10A is a plan view, and FIG. 10A is a sectional view taken along line Xb-Xb of FIG. 10A.

Hereinafter, the present invention will be described. It should be understood that the terms used herein are used in the meaning commonly used in the art unless otherwise noted. Thus, unless otherwise defined, all terminology and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, this specification (including definitions) takes precedence.

(Definition of terms)
As used herein, the term "circuit pattern" refers to a conductive layer patterned so as to form a predetermined circuit.

In the present specification, "the adhesive portion is arranged independently of the circuit pattern" means that the adhesive portion is arranged independently of the circuit pattern and is not arranged depending on the circuit pattern. Say. The phrase "the bonded portion is arranged depending on the circuit pattern" as used herein means that when the circuit board is viewed from above, the region composed of the bonded portion and the circuit pattern are almost the same (for example, 80%). It means the state where they are arranged so as to match the above.

In the present specification, the expansion / contraction ratio is described using 50% modulus as an index. 50% modulus is defined as "load per unit area at 50% elongation (MPa)", "high stretch ratio" means small 50% modulus, and "low stretch ratio" It means that the 50% modulus is large.

In the present specification, the "tensile strength" and "tensile elongation" of the resin are the maximum force (tensile strength: MPa) that can be withstood when pulled and how much the resin is stretched at that time, as measured according to JIS K7311. (Tensile elongation:%).

In the present specification (the present invention), "peeling strength" refers to an average value of values measured three times using a tensile tester.

In the present specification (the present invention), the "elastic modulus" means an average value of values (storage elastic modulus) measured three times using a dynamic viscoelastic device.

As used herein, the term "weight average molecular weight" refers to a value measured by gel permeation chromatography (GPC) using standard polystyrene having an average molecular weight of about 5 to about 1 million.

As used herein, the term "about" means within ± 10% of the numbers that follow.

(1. Elastic base material)
An object of the present invention is to provide a circuit board having sufficient elasticity (for example, 50% modulus of about 1.0 or less).
(1) It is an elastic base material and
With the textile layer,
A resin layer covering the textile layer and
An elastic base material including an adhesive layer including a plurality of adhesive portions for adhering the textile layer and the resin layer, and an elastic base material.
(2) The above problem is solved by providing a circuit board including a circuit pattern formed on the resin layer.

The thickness of the stretchable substrate can be arbitrary. It is preferably about 0.25 mm to about 1.0 mm, and more preferably about 0.5 mm to about 0.75 mm. However, the present invention is not limited to this.

(1.1 Textile layer)
The textile layer in the stretchable substrate of the present invention may include any material recognized as a fibrous structure such as woven fabrics, knitted fabrics, non-woven fabrics, braided nets including strings and ropes. Any material can be used as the material of the textile layer, but it is preferable to use a fabric having a high elongation rate in order to obtain elasticity. For example, in one embodiment, the elongation rate of the dough used in the present invention is about 200 to 320% in one direction and about 70 to 70 in the direction orthogonal to one direction when a force of 9.8 N is applied in one direction. 190%, more specifically, about 220 to 280% in one direction, about 110 to 150% in the direction orthogonal to one direction, for example, about 260% in one direction, the direction orthogonal to one direction. About 130% can be used. For example, polyurethane, polyester, or nylon, preferably polyester having heat resistance in addition to elasticity.

The ratio of the area of the circuit pattern to the area of the textile layer is arbitrary, for example, about 1-30%, about 3-30%, about 5-30%, about 10-30%, about 1-20%, about. It can be 3 to 20%, about 5 to 20%, about 10 to 20%, about 1 to 10%, about 3 to 10%, about 5 to 10%, and the like.

In one embodiment, the tensile strength of the textile layer of the present invention can be about 250-650 MPa, about 300-500 MPa, or about 350-450 MPa. As one specific example, the tensile strength of the textile layer is about 380 MPa.
The specific measurement conditions are as shown below.
-Measuring device: Autograph AG-10TB manufactured by Shimadzu Corporation
・ Load cell: Approximately 5 kN
・ Test speed: Approximately 100 mm / min ・ Distance between chucks: Approximately 30 mm
・ Chuck length: Approximately 30 mm on each side
-Sample shape: A rectangular shape with a length of about 100 mm and a width of about 20 mm.

(1.2 resin layer)
Examples of the resin constituting the resin layer of the present invention include polyester resin, polyurethane resin, polyurethane polyurea resin, polyamide resin, polyimide resin, polycarbonate resin, polyphenylene ether resin, styrene-based elastomer, fluororesin, styrene maleic anhydride-based resin, and LCP. (Liquid crystal polymer) Resin and the like can be mentioned, but the present invention is not limited thereto. Preferably, the resin constituting the resin layer of the present invention is a thermoplastic resin, particularly preferably a polyurethane resin, and even more preferably an ester-based urethane resin.

In one embodiment, the tensile strength of the resin layer of the present invention can be from about 250 to about 650 MPa, from about 300 to about 500 MPa, or from about 350 to about 450 MPa. As one specific example, the tensile strength of the resin layer is about 380 MPa.
The specific measurement conditions are as follows, as in the method for measuring the tensile strength of the textile layer.
-Measuring device: Autograph AG-10TB manufactured by Shimadzu Corporation.
-Load cell: Approximately 5 kN.
-Test speed: Approximately 100 mm / min.
・ Distance between chucks: Approximately 30 mm
・ Chuck length: Approximately 30 mm on each side
-Sample shape: A rectangular shape with a length of about 100 mm and a width of about 20 mm.

In one embodiment, the tensile elongation of the resin layer of the present invention can be about 300-700%, about 400-600%, or about 450-550%. As one specific example, the tensile elongation of the resin layer is about 500%.

In one embodiment, the elastic modulus (storage elastic modulus) of the resin layer of the present invention can be about 1 MPa to about 100 MPa, about 5 to about 80 MPa, or about 8 to about 40 MPa. As one specific example, the elastic modulus (storage elastic modulus) of the resin layer is about 10 MPa. The specific measurement conditions are shown below.
-Dynamic viscoelasticity measuring device: Made by RSA-GII TA Instruments Japan Co., Ltd.
-Sample shape: Width approx. 8 mm x Length approx. 20 mm (distance between chucks) x Thickness approx. 30 mm.
-Test measurement method: Tension mode.
-Temperature condition: heating rate of about 10 ° C / min, 1 Hz.

(1.3 Adhesive layer)
The adhesive layer of the present invention is a layer composed of a plurality of adhesive portions arranged independently of the circuit pattern.

The adhesive portion of the present invention may be formed by thermocompression bonding between the resin constituting the adhesive portion and the textile layer. For the resin, for example, an elastomer-based adhesive, a thermosetting adhesive, or a thermoplastic adhesive can be used. Here, the adhesive portion means a surface where the textile layer and the resin layer are adhered when the resin layer and the textile layer are directly thermocompression bonded, and an additional resin is interposed between the resin layer and the textile layer. In the case of forming the adhesive portion, the adhesive portion includes the surface from the adhesive surface of the further resin with the resin layer to the adhesive surface of the further resin with the textile layer.

The resin layer and the adhesive portion may be the same type of resin or different types of resin. Further, the elastic modulus of the resin layer and the bonded portion is preferably lower in the bonded portion. This makes it easier for the resin layer to follow when the textile layer expands and contracts.

In one embodiment, the elastic modulus (storage elastic modulus) of the adhesive layer of the present invention can be about 1 MPa to 80 MPa, about 5 MPa to 70 MPa, and about 5 MPa to about 30 MPa. The measurement conditions are the same as for the elastic modulus (storage elastic modulus) of the resin layer, so they are omitted here.

Further, the tensile strengths of the textile layer and the resin layer are preferably substantially the same (for example, within ± 20%, more preferably within ± 10% with respect to each other). This improves the elasticity of the circuit board. Although it is not desired to be bound by the theory, it is possible to obtain the adhesiveness in adhesion more effectively by adopting the above configuration.

In the embodiment in which a resin different from the resin layer is used in the adhesive portion, the peel strength of the adhesive portion of the present invention is, for example, at least about 180 g / cm or more, preferably at least about 200 g / cm or more, and more preferably at least about 500 g / cm. It can be cm or more, particularly preferably at least about 700 g / cm or more, for example about 700 to about 1000 g / cm. When the peel strength of the bonded portion is large, the risk of peeling between the textile layer and the resin layer when the stretchable circuit board is greatly stretched can be reduced. The circuit arranged on the peeled resin layer is not restricted by the textile layer, and as a result, it comes into contact with an unintended object, which may cause damage to the circuit and electrical defects. This can be a particular problem when used on clothing and the like.

It should be noted that in the present invention, the adhesive layer does not adhere the resin layer and the textile layer over the entire surface (for example, 80% or more), but is composed of a plurality of adhesive portions spaced apart from each other. When the adhesive layer and the textile layer are adhered over the entire surface, the textile layer is constrained by the adhesive layer, so that it is difficult to provide a circuit board having a 50% modulus of about 1.0 or less as in the present invention. obtain.

The plurality of adhesive portions can be arranged at arbitrary positions with respect to the resin layer. Further, the present inventors not only when the resin layer and the textile layer are bonded over the entire surface (for example, 80% or more) of the resin layer and the textile layer, but also the arrangement of the bonded portion and the arrangement of the circuit pattern are common. Then, it was found that the elasticity of the circuit pattern was reduced due to the hardening of the bonded portion. Therefore, in a preferred embodiment, the plurality of bonded portions are arranged at positions independent of the circuit pattern. By doing so, it is possible to provide a circuit board having sufficient elasticity (for example, 50% modulus of about 1.0 or less) as in the present invention. In particular, some conventional elastic circuit boards achieve elasticity only in a certain direction, but the elastic circuit board of the present invention has sufficient elasticity in any direction (for example, about 1). A 50% modulus (less than or equal to 0.0) can be achieved.

The distance between adjacent adhesive portions among the plurality of adhesive portions can be any distance. It is preferably about 0.7 mm to about 2.0 mm, and more preferably, for example, about 1 mm to about 1.5 mm, but the present invention is not limited thereto. As described above, by appropriately providing the distance between the plurality of bonded portions, a circuit board having sufficient elasticity (for example, 50% modulus of about 1.0 or less) as in the present invention can be provided.

The total ratio of the areas of the plurality of bonded portions to the area of the resin layer can be any numerical value of less than 80%. In one embodiment, 70% or less, 60% or less, preferably 50% or less, more preferably 40% or less, but the present invention is not limited thereto. More specifically, the total proportion of the areas of the plurality of bonded portions of the present invention can be any value between about 15% and less than about 80%. In one embodiment, the higher the proportion of the total of this area, which can be about 25% to about 70%, about 30% to about 60%, preferably about 35% to about 55%, the higher the peel strength. On the other hand, the elasticity of the circuit board is reduced. On the contrary, as the ratio of the total of these areas is lowered, the peel strength is lowered, and the elasticity of the circuit board can be improved. The present inventors have found that by appropriately setting this ratio, sufficient elasticity of the circuit board (for example, 50% modulus of about 1.0 or less) can be achieved, and the present invention is completed. I let you.

The 50% modulus of the circuit board is about 1.0 (MPa) or less, preferably about 0.9 (MPa) or less, more preferably about 0.8 (MPa) or less, but the present invention is not limited thereto. .. In the elastic substrate of the present invention, by achieving the above numerical values, it can be attached to a moving part of the body such as a vital sensor or a healthcare device, or a part that needs to follow the movement of a three-dimensional object. It became possible to do.

The arrangement of the plurality of adhesive portions may be a regular arrangement or an irregular arrangement.

In one embodiment, the arrangement of the plurality of adhesive portions is a staggered arrangement, but the present invention is not limited to this. For example, the arrangement of the plurality of adhesive portions may be in a grid pattern or in a spiral pattern. For example, the arrangement of the plurality of bonded portions is preferably an interval of about 0.7 mm to about 2.0 mm in one direction, an interval of about 0.7 mm to about 2.0 mm in the direction orthogonal to one direction, and further. Preferably, it can be from about 1 mm to about 1.5 mm. In the embodiment in which the plurality of adhesive portions are arranged in a staggered pattern, the distance in one direction is about 0.7 mm to about 2.0 mm, and the length in the direction orthogonal to one direction is about 1.4 mm to about 4. It can be 0 mm apart.

The area of each of the plurality of bonded portions can be arbitrary. It is preferably about 0.4 mm ² to about 1.8 mm ² , and more preferably about 0.5 mm ² to about 1.3 mm ² . However, the present invention is not limited to this.

The shape of the plurality of bonded portions can be any shape. For example, it may have a substantially circular shape, a substantially elliptical shape, a quadrangular shape, a triangular shape, or the like. Further, in the embodiment in which the plurality of bonded portions are substantially circular, the size of each of the bonded portions is preferably about 0.7 mm to about 1.5 mm in diameter, and more preferably about 0.8 mm to about 1.3 mm in diameter. Can be.

(2. Circuit pattern)
The thickness of the circuit pattern can be arbitrary. It is preferably about 0.005 mm to about 0.02 mm, and more preferably about 0.010 mm to about 0.014 mm. However, the present invention is not limited to this. If the thickness of the circuit pattern is too thick, the elasticity may decrease. Further, if the thickness of the circuit pattern is too thin, there is a risk of disconnection due to expansion and contraction. It is preferable to appropriately set the thickness according to the elasticity and strength required for the circuit board.

The circuit pattern can be a conductive composition containing any metal that conducts electricity. In one embodiment, it is formed by a conductive composition comprising silver, but the present invention is not limited thereto. For example, it may contain a metal other than silver such as copper and gold.

The conductive composition may further comprise a stretchable material. By including the stretchable material, it is possible to more effectively suppress disconnection due to expansion and contraction of the circuit pattern due to expansion and contraction due to the elastic base material and the resin layer. The stretchable material can be any material. In one embodiment, it is a thermoplastic resin, but the present invention is not limited thereto. The conductive composition of the present invention may contain a composition similar to that of the resin layer in order to enhance the adhesion to the resin layer. For example, when the resin layer is a urethane layer, the conductive composition for forming the circuit pattern also contains a urethane component, and when the resin layer is formed of a polyethylene layer, the circuit. It is preferable that the conductive composition for forming the pattern contains a polyethylene component.

The resin layer may contain a thermoplastic resin material. By including the thermoplastic resin material, it becomes possible to effectively obtain elasticity.

The conductive resin used in the present invention may be disclosed in International Publication No. 2017/026130.

(3. Product)
Products including circuit boards are selected from the group consisting of clothing, shoes, footwear, gloves, toys, in-vehicle seats, healthcare equipment and the like. The circuit board of the present invention having elasticity can be used for clothes, footwear, a driving part such as a robot arm, etc., which cannot be mounted due to a circuit disconnection in the conventional flexible board due to continuous expansion and contraction. ..

(Specific embodiment)
In the following embodiments, as an example of the circuit board, the textile layer is knitted, the resin layer is a urethane layer, and the adhesive used for the adhesive portion is a thermosetting resin or a thermoplastic resin, which constitutes a circuit pattern. The material is silver. However, the present invention is not limited to the following embodiments. As long as it is possible to provide a circuit board having sufficient elasticity (for example, 50% modulus of about 1.0 or less) by having a plurality of adhesive portions for adhering the textile layer and the resin layer, the textile layer, the resin It is understood that the layer, the adhesive portion, the shape, material, type, and characteristic of the circuit pattern, and the positional relationship between the adhesive portion and the circuit pattern are not particularly limited.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram for explaining the circuit board 1 according to the first embodiment of the present invention, and FIGS. 1 (a) and 1 (b) are perspective views and plan views showing the appearance of the circuit board 1, respectively. Yes, FIG. 1 (c) is a sectional view taken along line Ic-Ic of FIG. 1 (b).

The circuit board 1 has an elastic base material 100 and a circuit pattern 10. The stretchable base material 100 has a textile layer 110, a resin layer 120 that covers the textile layer, and an adhesive layer 130 that adheres the textile layer 110 and the resin layer 120. The adhesive layer 130 has a structure in which adhesive portions for adhering the textile layer 110 and the resin layer 120 are dispersed in a plurality of places. The circuit pattern 10 is formed on the surface of the resin layer 120. The circuit pattern refers to a conductive layer patterned by, for example, screen printing so as to form a predetermined circuit. The means for forming the circuit pattern on the resin layer can be any means such as flexographic printing, gravure offset printing, and dispenser type.

Here, the textile layer 110 is a knitted fabric or the like having a high elasticity, and polyester, nylon or the like can be used as the material. The resin layer 120 is a urethane layer, and the adhesive constituting the adhesive layer 130 is a thermoplastic resin. However, the textile layer 110, the resin layer 120, and the adhesive layer 130 are not limited to these materials. For example, the textile layer 110 may be a woven fabric or a non-woven fabric, and the resin layer 120 may be any elastic material. The adhesive constituting the adhesive layer 130 may be a thermosetting resin.

2 and 3 are views schematically showing a detailed structure of the circuit board 1 shown in FIG. 1, and FIG. 2 (a) is an enlarged view of an IIa portion of FIG. 1 (b), FIG. 2 (b). ) Is a sectional view taken along line IIb of FIG. 2 (a). FIG. 3 is an enlarged perspective view of a portion III of FIG. 1A. In FIG. 3, the adhesive portion 130a and the textile layer 110 on the lower side of the resin layer 120 from above the circuit board 1 shown in FIG. 1A are shown. Is seen through.

[Stretchable base material 100]
Here, as shown in FIGS. 2 (a) and 2 (b), the knitted textile layer 110 has a structure in which a plurality of linear fiber mass portions 110a are arranged in a certain direction. As shown in FIG. 7B, the textile layer 110, which is a knitted fabric, actually has fibers extending from the fiber mass 110a to the opposite side of the resin layer, but FIGS. 2 and 2 and FIG. It is omitted in 3.

The resin layer 120 is characterized by having elasticity. In one embodiment, a thermoplastic elastomer is used for the resin layer, and a urethane resin is particularly preferable from the viewpoint of elasticity, and more preferably, an ester-based urethane resin composed of diphenylmethane diisocyanate and an aliphatic ester-based resin is used. preferable. Further, it is preferable to use a solvent (butycarbitol acetate, dimethylacetamide, diethylene glycol monobutyl ether, carbitol acetate, etc.) as the printing paste (ink) used for printing the circuit pattern 10 formed on the resin layer 120. A rubber-based material other than the urethane resin can be used for the resin layer 120, and not only the thermoplastic elastomer but also a thermosetting elastomer and the like may be used.

In one embodiment, the adhesive layer 130 uses a thermosetting resin such as a hot melt resin or a thermoplastic resin, and preferably an ester-based urethane resin composed of hexamethylene diisocyanate and an aromatic ester-based resin. .. The adhesive layer 130 is not formed over the entire surface between the textile layer 110 and the resin layer 120, but is staggered between the textile layer 110 and the resin layer 120 as shown in FIG. 2 (a). It is composed of a plurality of adhesive portions 130a arranged in the above. As the specific material of the adhesive portion 130a, the same urethane-based material is used from the viewpoint of adhesion to the resin layer 120 which is a urethane resin. However, the adhesive layer 130 is not limited to the hot melt resin or the like, and an ultraviolet curable resin or the like can also be used. Further, the adhesive portion may be formed by thermocompression bonding the resin layer directly to the textile layer.

Here, the distance between the adjacent adhesive portions 130a is about 1.25 mm, and the area between the adjacent adhesive portions 130a is a region that does not contain the adhesive. Therefore, the resin layer 120 is adhered to the fiber mass portion 110a by the adhesive portion 130a.

Further, the ratio of the total area of the plurality of bonded portions to the area of the resin layer is about 50% in one embodiment. However, the ratio is not limited to this, and it is sufficient that the circuit board has elasticity and peel strength to achieve sufficient elasticity (for example, 50% modulus of about 1.0 or less). For example, when the textile layer 110 is thin, the adhesive portion 130a tends to swell, so it is desirable to reduce the area of the adhesive portion 130a. When the textile layer 110 is thick, it is preferable to increase the area of the adhesive portion 130a to increase the peel strength between the adhesive portion 130a and the resin layer 120. One of the reasons for increasing the area of the adhesive portion 130a to improve the adhesion between the resin layer 120 and the textile layer 110 is to prevent the resin layer 120 and the textile from peeling off when the textile layer 110 is washed. Because. By setting the total ratio of the areas of the plurality of adhesive portions to the area of the resin layer to about 50%, the effect of suppressing the peeling of the resin layer 120 and the textile layer 110 during washing and the effect of suppressing the swelling of the adhesive portion 130a can be obtained. It can be obtained in a well-balanced manner.

In the illustrated embodiment, the arrangement of the plurality of adhesive portions 130a is a staggered arrangement. In one embodiment, in this staggered arrangement, the adhesive portions 130a are spaced about 0.7 to about 2.0 mm in one direction and about 0.7 to about 2.0 mm in the direction orthogonal to one direction. Is placed. Further, the arrangement of the plurality of adhesive portions 130a is not limited to the staggered arrangement, and may be another regular arrangement (lattice-like arrangement), and further, an irregular arrangement. You may.

In one embodiment, the area of each of the plurality of bonded portions is about 0.2 to 2.0 mm ² . However, the present invention is not limited to this, and is preferably about 0.4 mm depending on conditions such as sufficient elasticity (for example, 50% modulus of about 1.0 or less) and adhesion strength required for the circuit board 1. Those with an area of ² to about 1.8 mm ^{2 are used.} Further, preferably, the area of each of the plurality of bonded portions is about 0.5 mm ² to about 1.3 mm ² . In one embodiment, the shape of the plurality of bonded portions is a substantially circular shape, but the shape is not limited to this, and may be a substantially elliptical shape, a substantially quadrangular shape, a substantially triangular shape, or the like.

In one embodiment, the stretchable substrate has a thickness of 0.618 mm. However, the present invention is not limited to this, and is preferably about 0.25 mm to about 1.0 mm, and more preferably about 0.5 mm to about 0.75 mm.

[Circuit pattern 10]
Further, in one embodiment, a circuit pattern 10 made of a conductive composition containing Ag is formed on the surface of the resin layer 120. The thickness of this circuit pattern is about 0.012 mm. However, the thickness is not limited to this, and is preferably about 0.010 to about 0.02 mm, and more preferably about 0.010 mm to about 0.014 mm.

Further, the circuit pattern 10 preferably contains a composition similar to that of the resin layer 120 in order to enhance the adhesion to the resin layer 120. In one embodiment, since the resin layer 120 is a urethane layer, the conductive composition for forming the circuit pattern contains a urethane component. Therefore, when the resin layer 120 is formed of a polystyrene layer, it is preferable to include a polystyrene component in the conductive composition for forming the circuit pattern.

Further, the circuit pattern 10 may be made elastic by including the elastic material in the conductive composition. By giving the circuit pattern itself elasticity, it is possible to more effectively prevent disconnection of the circuit pattern due to expansion and contraction of the textile layer and the resin layer. Further, instead of including the elastic material in the conductive composition, a meander pattern in which the circuit pattern 10 meanders may be adopted. Further, by including the elastic material in the conductive composition and adopting the meander pattern as the circuit pattern, it is possible to prevent disconnection while maintaining more elasticity.

FIG. 4 is a diagram for explaining a specific example of the circuit pattern 10 shown in FIG. 1, and FIGS. 4 (a) to 4 (d) show specific examples of a meandering wiring pattern (munder pattern), respectively. ..

The circuit pattern 10a shown in FIG. 4A includes a wiring 13a that employs the first meander pattern, and both ends of the wiring 13a are connected to the electrode pads 11 and 12 via linear connecting portions 11a and 12a. There is. The wiring 13a adopting the first meander pattern is formed along a finely meandering zigzag path.
The circuit pattern 10b shown in FIG. 4B includes a wiring 13b that employs a second meander pattern instead of the wiring 13a of the circuit pattern 10. The wiring 13b is formed along a zigzag path that meanders finer than the first meander pattern, and the folded portion of the zigzag path has an arc shape.

The circuit pattern 10c shown in FIG. 4C includes a wiring 13c that employs a third meander pattern instead of the wiring 13a of the circuit pattern 10a. The wiring 13c is a semicircle connecting a plurality of straight line portions 13c1 having a constant length extending vertically on both sides of a straight line connecting a pair of electrode pads 11 and 12 facing each other and the tips of adjacent straight line portions 13c1. It is composed of a shaped portion 13c2.

The circuit pattern 10d shown in FIG. 4D includes a wiring 13d that employs a fourth meander pattern instead of the wiring 13a of the circuit pattern 10a. The wiring 13d is formed along a meandering path formed by connecting arcs of approximately 3/4 circles.

In the wirings 13a to 13d having such a meander pattern, the resistance to disconnection due to expansion and contraction and the increase in electrical resistance are increased in the order of the first to fourth meander patterns. However, the circuit pattern of the present invention is not limited to that shown in FIG. 4, and may have any shape.

The circuit patterns 10a to 10d described above are those in which both ends of the wiring adopting the meander pattern are connected to the electrode pads via linear connection portions, respectively, but these circuit patterns adopt the meander pattern. Both ends of the wiring may be directly connected to the electrode pads.

(Manufacturing method)
Next, an example of a method for manufacturing the circuit board 1 will be described.

First, an example of a method for manufacturing the elastic base material 100 constituting the circuit board 1 will be described.

FIG. 5 is a diagram for explaining a method of adhering the textile layer 110 to the resin layer 120 in the order of work steps, and FIGS. 5 (a) to 5 (f) show each work process. FIG. 6 is a diagram showing a mask member Ma used for selectively applying an adhesive to the surface of the resin layer 120 shown in FIG.

The resin layer 120 is placed on the support base K, and a printing mask Ma for selectively printing the adhesive is arranged on the surface of the resin layer 120 (FIG. 5A). Here, the print mask Ma has a plurality of mask openings Ma0, and the plurality of mask openings Ma0 have a plurality of mask openings Ma0 so that the plurality of adhesive portions 130a are arranged in a predetermined arrangement pattern (staggered pattern) on the resin layer 120. It is arranged in the same arrangement pattern as the arrangement pattern of the adhesive portion 130a. Further, the shape of the mask opening Ma0 is the same as the shape of the adhesive portion 130a.

Next, the adhesive (printing paste) is selectively printed on the resin layer 120 using the printing mask Ma (FIG. 5 (b)).

After the adhesive is dried (solvent evaporation), the printing mask Ma is removed (FIG. 5 (c)), and the textile layer 110 is placed on the resin layer 120 so as to cover the surface of the resin layer 120 (FIG. 5 (FIG. 5)). d)) In this state, the textile layer 110 is thermocompression bonded to the resin layer 120 by a roller R or a hot press (FIG. 5 (e)).

As a result, the adhesive 130a melts and soaks into the textile layer 110, and the soaked adhesive 130a solidifies in contact with the resin layer 120 (FIG. 5 (f)).

As a result, the stretchable base material 100 in which the resin layer 120 is adhered to the textile layer 110 is obtained. After that, the elastic base material 100 is removed from the support base K.

7 and 8 show photographs of the stretchable base material 100 obtained by adhering the resin layer 120 to the textile layer 110, and the surface of the resin layer 120 of the stretchable base material 100 is shown in FIG. It is shown in the photograph of (a), and the side surface of the elastic base material 100 is shown in the photograph of FIG. 7 (b). In the photograph of FIG. 7B, the adhesive portion 130a (inside the dotted square frame) soaked into the textile layer 110 is shown together with the fiber mass portion 110a and the resin layer 120. Further, the side surface of the elastic base material 100 that is orthogonal to the side surface shown in FIG. 7 (b) is shown in the photograph of FIG. 8 (a), and the details of the side surface shown in FIG. 8 (a) are shown in FIG. 8 (b). ) Is shown in the enlarged photograph.

Next, an example of a method of forming the circuit pattern 10 on the resin layer 120 of the stretchable base material 100 will be described. Here, printing of the conductive composition, for example, screen printing is used for forming the circuit pattern 10. The formation of the circuit pattern 10 is not limited to screen printing, but may be flexographic printing or gravure offset printing. Further, the formation of the circuit pattern 10 is not limited to printing, and a dispensing method of extruding the conductive composition from the needle tip may be used. Further, the conductive composition is not particularly limited, and for example, the material disclosed in International Publication 2017/026130 and the like can be used for the conductive composition. Further, a component (urethane) of the resin layer 120 which is a base for printing or a component close to the component (urethane) is preferable from the viewpoint of adhesion and the like.

FIG. 9 is a diagram for explaining an example of a method of forming the circuit pattern 10 on the resin layer 120 of the elastic base material 100 shown in FIG. 7 in the order of working steps, and FIGS. 9 (a) to 9 (c). Indicates each work process. 10A and 10B are views for explaining the screen printing machine P used for forming the circuit pattern 10, FIG. 10A is a plan view, and FIG. 10A is a sectional view taken along line Xb-Xb of FIG. 10A.

First, as shown in FIG. 9A, the elastic base material 100 obtained by adhering the resin layer 120 to the textile layer 110 is attached to the screen printing machine P.

As shown in FIGS. 10A and 10B, the screen printing machine P includes a printing table M on which the elastic base material 100 is placed, and a frame arranged on the printing table M and supporting the screen members Ps. It has Pf and squeeze Sq for extruding the print paste Pe held on the screen member Ps from the screen opening Ps0.

Next, as shown in FIGS. 9 (b) and 9 (c), the squeeze Sq is moved on the screen member Ps while pressing the screen member Ps against the surface of the resin layer 120 of the elastic base material 100 with the squeeze Sq. Then, the print paste Pe extruded from the screen opening Ps0 by the squeeze Sq is printed on the surface of the resin layer 120 in the same shape as the screen opening Ps0.

After that, when the solvent of the print paste Pe evaporates and the print paste Pe dries, a circuit pattern 10 made of silver contained in the print paste Pe is formed on the surface of the resin layer 120.

Such a circuit board 1 can be attached to clothing such as jeans, bedding such as a bed, a car seat, or the like, and can be used for detecting biological signals, heating by a heater, and pressure detection. ..

(Example)
In this embodiment, the elasticity of the circuit board 1 of the present invention is shown in comparison with the two comparative examples of the conventional circuit board and the textile layer only.

Here, the circuit board 1 of the present invention has a textile layer 110, an adhesive portion 130a, a resin layer (urethane layer) 120, and a circuit pattern 10, and the textile layer 110 and the resin layer 120 are substantially staggered. It is adhered by a plurality of adhesive portions 130a arranged in. The thickness of the circuit board 1 is about 0.658 mm, the thickness of the textile layer is about 0.618 mm, the thickness of the resin layer is about 0.028 mm, and the thickness of the circuit pattern is about 0.012 mm. Further, the distances between the adjacent adhesive portions arranged in a staggered manner are an average interval of about 1.25 mm in one direction and an average interval of about 2.35 mm in the direction orthogonal to one direction.

(Comparative example 1: Textile layer only)
Comparative Example 1 has a configuration consisting of only a textile layer. The textile layer used was the same as that used in the examples.

(Comparative Example 2: Conventional Circuit Board)
Comparative Example 2 (conventional circuit board) was the same as the circuit board 1 of the present invention except that the entire surface of the urethane layer covering the textile layer was hot-melt bonded.

<Evaluation of 50% modulus>
Examples and Comparative Examples 1 and 2 were cut into a width of 10 mm and a length of 40 mm, installed so that the distance between chucks was 30 mm, and a tensile tester was used to set the temperature at 23 ° C., humidity at 60% RH, and tensile speed: 300 mm /. It was extended to a length of 150% in min. At this time, the load and the load per unit area (50% modulus: MPa) were determined.

The smaller the value of 50% modulus, the smaller the force and the higher the elasticity. The results are shown in the table below.

表１から分かるように、本発明の回路基板１では、５０％伸張時の荷重が１．５６（Ｎ）であり、５０％モジュラスが０．２１である。従って、本発明の回路基板１の伸縮性は、比較例1（テキスタイル層のみ）の伸縮性とほぼ同等であり、比較例２（従来の回路基板）の伸縮性（５０％伸張時の荷重（７．７３Ｎ）および５０％モジュラス（１．２９））に比べると、大きく向上していることが分かる。

As can be seen from Table 1, in the circuit board 1 of the present invention, the load at 50% extension is 1.56 (N), and the 50% modulus is 0.21. Therefore, the elasticity of the circuit board 1 of the present invention is almost the same as the elasticity of Comparative Example 1 (textile layer only), and the elasticity of Comparative Example 2 (conventional circuit board) (load at 50% extension (load at 50% extension)). Compared with 7.73N) and 50% modulus (1.29)), it can be seen that there is a significant improvement.

As described above, in the first embodiment, the textile layer 110 and the resin layer 120 are formed in the circuit board 1 in which the circuit pattern 10 is formed on the elastic base material 100 having the structure in which the resin layer 120 is adhered to the textile layer 110 by the adhesive layer 130. Since the adhesive portions 130a with the cloth are dispersed and arranged at a plurality of places, the adjacent adhesive portions 130a are separated, and even if the adhesive portion 130a is cured, the adjacent adhesive portions 130a are within the range of deformation of the textile layer 110. It is possible to relatively displace within. As a result, it is possible to obtain an elastic circuit board 1 capable of suppressing a decrease in elasticity due to curing of the adhesive portion 130a.
(Example 2)
Table 2 below shows the results of testing the relationship between the peel strength and the expansion / contraction rate of the circuit board in the difference in the area of the bonded portion (bonding) in Example 2.

The circuit board 1 used in the second embodiment has a textile layer (fabric) 110, an adhesive portion 130a, a resin layer (urethane layer) 120, and a circuit pattern 10, and the textile layer 110 and the resin layer 120 are staggered. It is adhered by a plurality of adhesive portions 130a arranged in a shape. The thickness of the circuit board 1 is about 0.658 mm, the thickness of the textile layer is about 0.618 mm, the thickness of the resin layer is about 0.028 mm, and the thickness of the circuit pattern is about 0.012 mm. The dot diameters of small, medium, and large bonding are different from 0.6 mm, 0.86 mm, and 1.03 mm, respectively, and the dot area also differs depending on the dot diameter, but the distance between adjacent bonded parts arranged in a staggered pattern is one direction. It is generally common in that the average interval is about 1.20 to 1.27 mm in the (vertical direction) and the average interval is about 2.35 mm in the direction orthogonal to one direction (horizontal direction).

The results are shown in Table 2 below.

表２からわかるように、ボンディング小〜大のいずれも、タテ、ヨコ双方について１．０以下の５０％モジュラス値を満たしていた。
剥離強度については、ボンディング小よりもボンディング中または大の方が大きかった。引き延ばし使用におけるテキスタイル層と樹脂層との間で剥離を防ぐためには、ボンディング小よりも中または大が好ましい。樹脂層がテキスタイル層から剥離すると、製品化した際に樹脂上の回路が意図せぬ物体と接触してしまい、回路の破損及び電気的な不具合が生じ得るからである。

As can be seen from Table 2, both small to large bonding satisfied the 50% modulus value of 1.0 or less for both vertical and horizontal.
The peel strength was higher during or during bonding than at small bonding. In order to prevent peeling between the textile layer and the resin layer in stretched use, medium or large bonding is preferable to small bonding. This is because if the resin layer is peeled off from the textile layer, the circuit on the resin may come into contact with an unintended object when it is commercialized, which may cause damage to the circuit and electrical defects.

As described above, the present invention has been illustrated using the preferred embodiment of the present invention, but the present invention should not be construed as being limited to this embodiment. It is understood that the invention should be construed only by the claims. It will be understood by those skilled in the art that from the description of specific preferred embodiments of the present invention, an equivalent range can be implemented based on the description of the present invention and common general technical knowledge. It is understood that the references cited herein should be incorporated as reference to the present specification in the same manner that the content itself is specifically described herein.

In the field of circuit boards, the present invention suppresses a decrease in elasticity of a circuit board due to curing of an adhesive layer that adheres a textile layer and a resin layer, and has sufficient elasticity (for example, 50 of about 1.0 or less). It is useful as a circuit board having% modulus) can be obtained.

1 Circuit board 10, 10a to 10h Circuit pattern 11, 12 Electrode pads 13a to 13d Wiring 100 Elastic base material 110 Textile layer 110a Fiber mass 120 Resin layer 130 Adhesive part 130a Welding part M Printing table Ma Mask member P Screen printing machine Pf frame Pe print paste Ps screen member Ps0 screen opening Sq squeeze

Claims (15)

(1) It is an elastic base material and
With the textile layer,
A resin layer covering the textile layer and
An elastic base material including an adhesive layer including a plurality of adhesive portions for adhering the textile layer and the resin layer, and an elastic base material.
(2) A circuit board including a circuit pattern formed on the resin layer.
It has a peel strength of at least about 180 g / cm or more and a 50% modulus of about 1.0 or less, the 50% modulus being defined by "50% modulus = load at 50% elongation (MPa)". Circuit board. The circuit board according to claim 1, wherein the plurality of bonded portions are arranged independently of the circuit pattern. The circuit board according to claim 1 or 2, wherein the distance between the adjacent bonded portions among the plurality of bonded portions is about 0.7 mm to about 2.0 mm. The circuit board according to any one of claims 1 to 3, wherein the ratio of the total area of the plurality of bonded portions to the area of the resin layer is about 30% to about 60%. The circuit board according to any one of claims 1 to 4, wherein each of the plurality of bonded portions has an area of about 0.4 mm ² to about 1.8 mm ^2. The circuit board according to claim 5, wherein the plurality of bonded portions have a substantially circular shape. The circuit board according to claim 6, wherein the diameter of the bonded portion is about 0.7 mm to about 1.5 mm. The circuit board according to any one of claims 1 to 7, which has a peel strength of at least about 700 g / cm or more. The circuit board according to any one of claims 1 to 8, wherein the thickness of the stretchable base material is about 0.25 mm to about 1.0 mm. The circuit board according to any one of claims 1 to 9, wherein the thickness of the circuit pattern is about 0.005 mm to about 0.02 mm. The circuit board according to any one of claims 1 to 10, wherein the circuit pattern is formed of a conductive composition containing silver. The circuit board according to claim 11, wherein the conductive composition further comprises a stretchable material. The circuit board according to any one of claims 1 to 12, wherein the resin layer contains a thermoplastic resin material. A product comprising the circuit board according to any one of claims 1 to 13. The product according to claim 14, wherein the product is selected from the group consisting of clothing, shoes, footwear, gloves, toys, in-vehicle seats, healthcare devices and in-vehicle steering.

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