JP7235725B2 - elastic circuit board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stretchable circuit board.

2. Description of the Related Art Conventionally, as a circuit board, which is one of the main components of electronic equipment, a printed board in which a circuit pattern is printed on an insulating substrate has been used.

Such a printed circuit board includes not only a flexible circuit board having a bendable structure but also a stretchable circuit board having elasticity.

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

JP 2017-101124 A

However, the present inventors have found that the structure of the stretchable substrate disclosed in Patent Document 1 has a problem that the stretchability of the stretchable substrate is not sufficient due to the hardening of the hot-melt adhesive layer after thermocompression bonding. rice field.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a circuit board having sufficient stretchability (for example, a 50% modulus of about 1.0 or less).

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

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

In the present invention, a distance between adjacent bonded portions among the plurality of bonded 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 may have a 50% modulus of about 1.0 or less, and the 50% modulus may be defined by "50% modulus = load (MPa) at 50% elongation".

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

In the present invention, the plurality of bonding portions may be arranged in a zigzag pattern.

In the present invention, the staggered arrangement may be spaced about 0.7 mm to about 2.0 mm in one direction and about 0.7 mm to about 2.0 mm in a direction orthogonal to the one direction. .

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

In the present invention, the plurality of bonding portions may be substantially circular.

In the present invention, the elastic substrate may have a thickness of about 0.25 mm to about 1.0 mm.

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

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

In the present invention, the conductive composition may further contain an elastic material.

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

In the present invention, a product including the circuit board according to any one of claims 1 to 15 may be provided.

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

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

1A and 1B are diagrams for explaining a circuit board 1 according to Embodiment 1 of the present invention, and FIGS. 1A and 1B are respectively a perspective view and a plan view showing the appearance of the circuit board 1. FIG. 1(c) is a cross-sectional view taken along line Ic-Ic of FIG. 1(b). 2A and 2B are diagrams schematically showing the detailed structure of the circuit board 1 shown in FIG. 1, FIG. FIG. 2B is a cross-sectional view taken along the line IIb-IIb of FIG. 2(a); FIG. 3 is an enlarged perspective view of part III of FIG. 1(a). 4A to 4D are diagrams for explaining specific examples of the circuit pattern 10 shown in FIG. 1, and FIGS. meander pattern). FIG. 5 is a diagram for explaining the method of adhering the textile layer 110 to the resin layer 120 in order of working steps, and FIGS. 5(a) to 5(f) show the working steps. FIG. 6 shows a mask member Ma used to selectively apply 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 bonding the resin layer 120 to the textile layer 110. FIG. 7(a) shows the surface of the resin layer 120 of the elastic base material 100 7B is a photograph showing a side surface of the stretchable base material 100. FIG. 8A and 8B are diagrams for explaining the stretchable base material 100 shown in FIG. The photograph shown, FIG. 8(b), is an enlarged photograph of the side surface shown in FIG. 8(a). 9A to 9C are diagrams 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 order of work steps. ) indicates each work process. 10A and 10B are diagrams for explaining a screen printer P used for forming the circuit pattern 10. FIG. 10A is a plan view and a cross-sectional view taken along the line Xb-Xb of FIG. 10A.

The present invention will be described below. It should be understood that the terms used herein have the meanings commonly used in the art unless otherwise specified. Thus, unless defined otherwise, all technical 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, the present specification (including definitions) will control.

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

In this specification, the phrase "the adhesive part is arranged independently of the circuit pattern" means that the adhesive part is arranged independently of the circuit pattern and is not arranged depending on the circuit pattern. say. Here, the phrase “the adhesive part is arranged so as to follow the circuit pattern” means that when the circuit board is viewed from the top, the area constituted by the adhesive part and the circuit pattern are almost identical (for example, 80% above).

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

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

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

In this specification (the present invention), the term "elastic modulus" refers to the average value of three measurements (storage elastic modulus) using a dynamic viscoelasticity apparatus.

As used herein, "weight average molecular weight" refers to a value measured by gel permeation chromatography (GPC) using standard polystyrene having an average molecular weight of about 500 to about 1,000,000.

As used herein, "about" refers to within ±10% of the number that follows.

(1. Stretchable base material)
An object of the present invention is to provide a circuit board having sufficient stretchability (for example, a 50% modulus of about 1.0 or less),
(1) A stretchable base material,
a textile layer;
a resin layer covering the textile layer;
a stretchable base material comprising an adhesive layer including a plurality of adhesive portions for bonding the textile layer and the resin layer;
(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. Preferably from about 0.25 mm to about 1.0 mm, more preferably from about 0.5 mm to about 0.75 mm. However, the invention is not so limited.

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

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

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

(1.2 resin layer)
Resins constituting the resin layer of the present invention include polyester resins, polyurethane resins, polyurethane polyurea resins, polyamide resins, polyimide resins, polycarbonate resins, polyphenylene ether resins, styrene elastomers, fluororesins, styrene maleic anhydride resins and LCP. (Liquid crystal polymer) resins, etc., but not limited to these. Preferably, the resin constituting the resin layer of the present invention is a thermoplastic resin, particularly preferably a polyurethane resin, and 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, the same as in the method for measuring the tensile strength of the textile layer.
・Measuring device: Autograph AG-10TB manufactured by Shimadzu Corporation.
・Load cell: about 5 kN.
- Test speed: about 100 mm/min.
・Distance between chucks: about 30mm
・Chuck length: about 30mm on each side
・Sample shape: 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 modulus) of the resin layer of the present invention can be from about 1 MPa to about 100 MPa, from about 5 to about 80 MPa, or from about 8 to about 40 MPa. As one specific example, the elastic modulus (storage elastic modulus) of the resin layer is about 10 MPa. Specific measurement conditions are shown below.
・Dynamic viscoelasticity measuring device: RSA-GII, manufactured by TA Instruments Japan.
・Sample shape: about 8 mm wide x about 20 mm long (distance between chucks) x about 30 mm thick.
・Method of test measurement: Tensile mode.
・Temperature condition: temperature increase 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 forming the adhesive portion and the textile layer. For the resin, for example, an elastomer adhesive, a thermosetting adhesive, or a thermoplastic adhesive can be used. Here, the adhesive part means the surface where the textile layer and the resin layer are bonded when the resin layer and the textile layer are directly bonded by thermocompression, and an additional resin is interposed between the resin layer and the textile layer. In the case where the bonding portion is formed by forming the bonding portion, the bonding portion includes the bonding surface of the additional resin with the resin layer and the bonding surface of the additional resin with the textile layer.

The resin layer and the adhesive portion may be made of the same kind of resin, or may be made of different kinds of resin. Further, it is preferable that the elastic modulus of the resin layer and the adhesive portion is lower than that of the adhesive portion. This makes it easier for the resin layer to follow the expansion and contraction of the textile layer.

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

In addition, it is preferable that the textile layer and the resin layer have approximately the same tensile strength (for example, within ±20%, more preferably within ±10% of each other). This improves the stretchability of the circuit board. Although not wishing to be bound by theory, the above configuration makes it possible to obtain more effective adhesiveness in adhesion.

In embodiments in which a resin different from the resin layer is used in the adhesive portion, the adhesive portion of the present invention has a peel strength of, for example, at least about 180 g/cm or greater, preferably at least about 200 g/cm or greater, more preferably at least about 500 g/cm or greater. cm or more, particularly preferably at least about 700 g/cm or more, for example about 700 to about 1000 g/cm. If the peel strength of the adhesive portion is high, the risk of peeling between the textile layer and the resin layer can be reduced when the stretchable circuit board is greatly stretched. Circuits placed on the peeled resin layer may come into contact with unintended objects as a result of being unrestricted by the textile layer, resulting in circuit breakage and electrical failure. This can be a particular problem when used in clothing and the like.

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

A plurality of adhesive portions can be arranged at arbitrary positions with respect to the resin layer. Furthermore, the present inventors have found that 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 when the layout of the bonding portion and the layout of the circuit pattern are common As a result, the inventors have found that the stretchability of the circuit pattern decreases due to the hardening of the adhesive portion. Therefore, in a preferred embodiment, the plurality of bonds are positioned independently of the circuit pattern. By doing so, a circuit board having sufficient stretchability (eg, a 50% modulus of about 1.0 or less) can be provided as in the present invention. In particular, some conventional stretchable circuit boards achieve stretchability only in a certain direction, but the stretchable circuit board of the present invention has sufficient stretchability (for example, about 1 50% modulus of less than 0.0 can be achieved.

The distance between adjacent bonds of the plurality of bonds can be any distance. Preferably, it is about 0.7 mm to about 2.0 mm, and more preferably, for example, about 1 mm to about 1.5 mm, but the invention is not limited thereto. Thus, by appropriately setting the distance between a plurality of bonding portions, a circuit board having sufficient stretchability (for example, 50% modulus of about 1.0 or less) can be provided as in the present invention.

The ratio of the total area of the plurality of bonding portions to the area of the resin layer may be any numerical value less than 80%. In one embodiment, it is 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 percentage of the total area of a plurality of bonds of the present invention can be any number from about 15% to less than about 80%. In one embodiment, a higher percentage of this total area, which can be from about 25% to about 70%, from about 30% to about 60%, preferably from about 35% to about 55%, increases the peel strength. While it can be done, the stretchability of the circuit board is reduced. Conversely, the lower the ratio of the total area, the lower the peel strength, and the more the stretchability of the circuit board can be improved. The present inventors have found that by appropriately setting this ratio, it is possible to achieve sufficient stretchability of the circuit board (for example, a 50% modulus of about 1.0 or less), and completed the present invention. let me

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. . By achieving the above numerical values, the stretchable substrate of the present invention can be attached to parts that need to follow the movement of three-dimensional objects and movable parts of the body that stretch greatly, such as vital sensors and healthcare equipment. became possible.

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

In one embodiment, the arrangement of the adhesive portions is a staggered arrangement, but the invention is not limited to this. For example, the plurality of bonding portions may be arranged in a grid pattern or in a spiral pattern. For example, the arrangement of the plurality of adhesive parts is preferably about 0.7 mm to about 2.0 mm apart in one direction and about 0.7 mm to about 2.0 mm in the direction orthogonal to the one direction, and further Preferably, it may be from about 1 mm to about 1.5 mm. In an embodiment in which a plurality of adhesive portions are arranged in a staggered manner, the spacing in one direction is about 0.7 mm to about 2.0 mm, and the length in the direction perpendicular to the one direction is about 1.4 mm to about 4.0 mm. It can be 0 mm spacing.

The area of each of the plurality of bonding portions may be arbitrary. Preferably from about 0.4 mm ² to about 1.8 mm ² , more preferably from about 0.5 mm ² to about 1.3 mm ² . However, the invention is not so limited.

The shape of the plurality of bonding portions can be any shape. For example, it may have a substantially circular shape, a substantially elliptical shape, a square shape, a triangular shape, or the like. Also, in embodiments in which the plurality of bonds are generally circular, the size of each bond is preferably from about 0.7 mm to about 1.5 mm in diameter, more preferably from 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. Preferably from about 0.005 mm to about 0.02 mm, more preferably from about 0.010 mm to about 0.014 mm. However, the invention is not so limited. If the thickness of the circuit pattern is too thick, there is a risk that the stretchability will decrease. Also, 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 stretchability and strength required for the circuit board.

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

The electrically conductive composition may further comprise a stretchable material. By containing the elastic material, it becomes possible to more effectively suppress disconnection or the like due to expansion and contraction of the circuit pattern due to expansion and contraction of 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 invention is not so limited. The electrically conductive composition of the present invention may contain a composition similar to that of the resin layer in order to improve 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 The electrically conductive composition for forming the pattern preferably contains a component of polyethylene.

The resin layer may contain a thermoplastic resin material. By including a thermoplastic resin material, it is possible to effectively obtain stretchability.

The conductive resin used in the present invention can be those disclosed in WO2017/026130.

(3. Products)
The product containing the circuit board is selected from the group consisting of clothing, shoes, footwear, gloves, toys, car seats, healthcare equipment, and the like. The stretchable circuit board of the present invention can be used for clothes, footwear, robot arms, and other driving parts that could not be worn on conventional flexible boards due to circuit breakage due to continuous expansion and contraction. .

(Specific embodiment)
In the following embodiments, as an example of the circuit board, the textile layer is a knitted fabric, the resin layer is a urethane layer, and the adhesive used for the bonding portion is a thermosetting resin or a thermoplastic resin, and constitutes the circuit pattern. The material is silver. However, the present invention is not limited to the following embodiments. Textile layer, resin layer, as long as it can provide a circuit board having sufficient stretchability (e.g., 50% modulus of about 1.0 or less) by having a plurality of adhesive portions that bond the textile layer and the resin layer It is understood that there are no particular limitations on the shape, material, type, and characteristics of the layer, the bonding portion, and the circuit pattern, and the positional relationship between the bonding portion and the circuit pattern.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

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

This circuit board 1 has a stretchable base material 100 and a circuit pattern 10 . The elastic base material 100 has a textile layer 110 , a resin layer 120 covering the textile layer, and an adhesive layer 130 bonding the textile layer 110 and the resin layer 120 together. The adhesive layer 130 has a structure in which adhesive portions for bonding the textile layer 110 and the resin layer 120 are dispersed at a plurality of locations. Circuit pattern 10 is formed on the surface of resin layer 120 . In addition, 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 may be any means such as flexographic printing, gravure offset printing, dispenser type, and the like.

Here, the textile layer 110 is a highly stretchable knitted fabric such as a knit, and the material thereof may be polyester, nylon, or the like. The resin layer 120 is a urethane layer, and the adhesive forming the adhesive layer 130 is a thermoplastic resin. However, textile layer 110, resin layer 120, and adhesive layer 130 are not limited to these materials. For example, the textile layer 110 may be woven or non-woven, and the resin layer 120 may be any stretchable material. The adhesive forming the adhesive layer 130 may be a thermosetting resin.

2 and 3 are diagrams schematically showing the detailed structure of the circuit board 1 shown in FIG. 1, FIG. ) is a sectional view taken along line IIb of FIG. 2(a). FIG. 3 is an enlarged perspective view of part III of FIG. 1(a), and in FIG. is transparent.

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

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

In one embodiment, the adhesive layer 130 is made of a thermosetting resin such as a hot melt resin or a thermoplastic resin, preferably an ester-based urethane resin composed of hexamethylene diisocyanate and an aromatic ester. . 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. It is composed of a plurality of adhesive portions 130a arranged in a row. The same urethane-based material is used as a specific material for the adhesive portion 130a from the viewpoint of adhesion with the resin layer 120, which is a urethane resin. However, the adhesive layer 130 is not limited to the hot-melt resin and the like, and an ultraviolet curable resin or the like can also be used. Alternatively, 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 approximately 1.25 mm, and the adjacent adhesive portions 130a are regions in which no adhesive is contained. Therefore, the resin layer 120 is adhered to the fiber mass portion 110a and the adhesion portion 130a.

Furthermore, the ratio of the total area of the plurality of bonding portions to the area of the resin layer is about 50% in one embodiment. However, it is not limited to this ratio, as long as it has stretchability and peel strength that achieve sufficient stretchability of the circuit board (for example, a 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. Moreover, when the textile layer 110 is thick, it is preferable to increase the peel strength between the adhesive portion 130a and the resin layer 120 by increasing the area of the adhesive portion 130a. One of the reasons for increasing the adhesion between the resin layer 120 and the textile layer 110 by increasing the area of the adhesive portion 130a is to prevent the resin layer 120 from peeling off from the textile when the textile layer 110 is washed. It's for. By setting the ratio of the total area of the plurality of adhesive portions to the area of the resin layer to about 50%, the effect of suppressing separation between the resin layer 120 and the textile layer 110 during washing and the effect of suppressing the swelling of the adhesive portion 130a are suppressed. You can get a good balance.

In the illustrated embodiment, the plurality of adhesive portions 130a are arranged in a staggered arrangement. In one embodiment, in this staggered arrangement, adhesives 130a are spaced about 0.7 to about 2.0 mm apart in one direction and about 0.7 to about 2.0 mm apart in a direction perpendicular to the one direction. are placed. In addition, the arrangement of the plurality of bonding portions 130a is not limited to the zigzag arrangement, and may be another regular arrangement (lattice arrangement) or may be an irregular arrangement. may

In one embodiment, the area of each of the plurality of bonds is about 0.2-2.0 mm ² . However, it is not limited to this, and depending on conditions such as sufficient stretchability (for example, 50% modulus of about 1.0 or less) and adhesion strength required of the circuit board 1, it is preferably about 0.4 mm Areas of ² to about 1.8 mm ² are used. Further preferably, the area of each of the plurality of bonds is between about 0.5 mm ² and about 1.3 mm ² . In one embodiment, the shape of the plurality of bonding portions is substantially circular, but the shape is not limited to this, and may be substantially elliptical, substantially quadrangular, substantially triangular, or the like.

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

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

Moreover, the circuit pattern 10 preferably contains a composition similar to that of the resin layer 120 in order to enhance adhesion with 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, the conductive composition for forming the circuit pattern preferably contains a polystyrene component.

Alternatively, the circuit pattern 10 may be made stretchable by including a stretchable material in the conductive composition. By imparting elasticity to the circuit pattern itself, 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. Also, instead of including an elastic material in the conductive composition, a meander pattern in which the circuit pattern 10 meanders may be employed. Further, by including a stretchable material in the conductive composition and adopting a meander pattern for the circuit pattern, it becomes possible to prevent disconnection while maintaining stretchability.

FIG. 4 is a diagram for explaining a specific example of the circuit pattern 10 shown in FIG. 1, and FIGS. 4A to 4D each show a specific example of a meandering wiring pattern (meandering pattern). .

A circuit pattern 10a shown in FIG. 4(a) includes a wiring 13a employing a first meander pattern, and both ends of the wiring 13a are connected to 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.
A circuit pattern 10b shown in FIG. 4B includes a wiring 13b employing a second meander pattern instead of the wiring 13a of the circuit pattern 10. As shown in FIG. The wiring 13b is formed along a meandering zigzag path that is finer than the first meander pattern, and the folded portion of the zigzag path is arcuate.

A circuit pattern 10c shown in FIG. 4C includes wiring 13c employing a third meander pattern instead of the wiring 13a of the circuit pattern 10a. This wiring 13c has a plurality of straight portions 13c1 of a certain length extending vertically on both sides of a straight line connecting a pair of opposing electrode pads 11 and 12, and a semicircle connecting the tips of the adjacent straight portions 13c1. It is composed of a shaped portion 13c2.

A circuit pattern 10d shown in FIG. 4D includes a wiring 13d employing 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 meander patterns, resistance to disconnection due to expansion and contraction and increase in electrical resistance increases in the order of the first to fourth meander patterns. However, the circuit pattern of the present invention is not limited to the one shown in FIG. 4 and may be of any shape.

In the circuit patterns 10a to 10d described above, both ends of the wiring adopting the meander pattern are connected to the electrode pads via linear connecting portions, respectively. 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 producing the stretchable base material 100 that constitutes the circuit board 1 will be described.

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

A resin layer 120 is placed on a support base K, and a printing mask Ma for selectively printing an adhesive is arranged on the surface of the resin layer 120 (FIG. 5(a)). Here, the printing mask Ma has a plurality of mask openings Ma0, and the plurality of mask openings Ma0 are arranged such that the plurality of adhesive portions 130a are arranged in a predetermined array pattern (staggered pattern) on the resin layer 120. They are arranged in the same arrangement pattern as the arrangement pattern of the bonding portions 130a. Also, the shape of the mask opening Ma0 is the same as the shape of the bonding portion 130a.

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

After drying the adhesive (evaporating the solvent), the printing mask Ma is removed (FIG. 5(c)), and the textile layer 110 is put on the resin layer 120 so as to cover the surface of the resin layer 120 (FIG. 5 ( d)), in this state, the textile layer 110 is thermocompression-bonded to the resin layer 120 with 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 stretchable base material 100 is removed from the support K.

7 and 8 show photographs of the stretchable base material 100 obtained by bonding the resin layer 120 to the textile layer 110. The surface of the resin layer 120 of the stretchable base material 100 is shown in FIG. (a) is shown in the photograph, and the side surface of the stretchable substrate 100 is shown in the photograph in FIG. 7(b). In the photograph of FIG. 7(b), the adhesive portion 130a (inside the frame of the dotted square) that has permeated the textile layer 110 is shown together with the fiber mass portion 110a and the resin layer 120. As shown in FIG. Further, the side surface of the elastic base material 100 perpendicular 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. ) is a magnified 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, the circuit pattern 10 is formed by printing a conductive composition, such as screen printing. Formation of the circuit pattern 10 is not limited to screen printing, but may be flexographic printing or gravure offset printing. Furthermore, formation by printing is not limited, and a dispensing method in which a conductive composition is extruded from a needle tip may be used. Furthermore, although the conductive composition is not particularly limited, for example, materials disclosed in International Publication 2017/026130 can be used for the conductive composition. From the viewpoint of adhesiveness, etc., it is preferable to use a material that contains the component (urethane) of the resin layer 120 that serves as a base for printing or a component close thereto.

FIGS. 9A to 9C are diagrams 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 order of work steps. indicates each work process. 10A and 10B are diagrams for explaining a screen printer P used for forming the circuit pattern 10. FIG. 10A is a plan view and a cross-sectional view taken along the line Xb-Xb of FIG. 10A.

First, as shown in FIG. 9(a), the elastic base material 100 obtained by adhering the resin layer 120 to the textile layer 110 is attached to the screen printer P. As shown in FIG.

As shown in FIGS. 10(a) and 10(b), the screen printer P comprises a printing table M on which the stretchable base material 100 is placed, and a frame arranged on the printing table M and supporting the screen member Ps. Pf and a squeeze Sq for pushing out the printing paste Pe held on the screen member Ps from the screen opening Ps0.

Next, as shown in FIGS. 9B and 9C, 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 stretchable base material 100 with the squeeze Sq. Then, the printing paste Pe pushed out 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.

Thereafter, when the solvent of the printing paste Pe evaporates and the printing paste Pe dries, the circuit pattern 10 made of silver contained in the printing 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, or a seat of a car and the like, and can be used to detect biosignals, to detect heating by a heater, to detect pressure, and the like. .

(Example)
In this example, the stretchability of the circuit board 1 of the present invention is shown in comparison with two comparative examples of a conventional circuit board and a 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. are bonded by a plurality of bonding portions 130a arranged in the same direction. The thickness of the circuit board 1 is approximately 0.658 mm, the thickness of the textile layer is approximately 0.618 mm, the thickness of the resin layer is approximately 0.028 mm, and the thickness of the circuit pattern is approximately 0.012 mm. In addition, the distance between adjacent adhesive portions arranged in a zigzag pattern is an average interval of about 1.25 mm in one direction and an average interval of about 2.35 mm in a direction orthogonal to the one direction.

(Comparative Example 1: Textile layer only)
Comparative Example 1 has a configuration consisting only of 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 circuit board 1 of the present invention, except that the entire surface of the urethane layer covering the textile layer was subjected to hot-melt adhesion.

<Evaluation of 50% modulus>
Example and Comparative Examples 1 and 2 were cut into pieces of 10 mm in width and 40 mm in length, and placed so that the distance between chucks was 30 mm. It was extended to 150% length at min. At this time, the load and the load per unit area (50% modulus: MPa) were obtained.

The smaller the 50% modulus value, the smaller the force required for stretching, indicating that the stretchability is high. 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, the circuit board 1 of the present invention has a load of 1.56 (N) at 50% elongation and a 50% modulus of 0.21. Therefore, the stretchability of the circuit board 1 of the present invention is almost the same as the stretchability of Comparative Example 1 (textile layer only), and the stretchability of Comparative Example 2 (conventional circuit board) (load at 50% stretch ( 7.73 N) and 50% modulus (1.29)), it is found to be greatly improved.

As described above, in Embodiment 1, 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, the textile layer 110 and the resin layer 120 Since the adhesive portions 130a are dispersed and arranged at a plurality of locations, the adjacent adhesive portions 130a are separated, and even if the adhesive portions 130a are cured, the adjacent adhesive portions 130a remain within the range of deformation of the textile layer 110. It becomes possible to relatively displace within. As a result, it is possible to obtain a stretchable circuit board 1 that can suppress deterioration in stretchability due to hardening of the adhesive portion 130a.
(Example 2)
In Example 2, the relationship between the peel strength and expansion ratio of the circuit board was tested for different areas of the bonding portion (bonding), and the results are shown in Table 2 below.

The circuit board 1 used in Example 2 has a textile layer (fabric) 110, an adhesive portion 130a, a resin layer (urethane layer) 120, and a circuit pattern 10. The textile layer 110 and the resin layer 120 are staggered. It is bonded by a plurality of bonding portions 130a arranged in a shape. The thickness of the circuit board 1 is approximately 0.658 mm, the thickness of the textile layer is approximately 0.618 mm, the thickness of the resin layer is approximately 0.028 mm, and the thickness of the circuit pattern is approximately 0.012 mm. Small, medium, and large bonding have different dot diameters of 0.6 mm, 0.86 mm, and 1.03 mm, respectively. They are generally common in that they have an average interval of about 1.20 to 1.27 mm in the vertical direction and an average interval of 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, all of the small to large bondings satisfied the 50% modulus value of 1.0 or less in both the vertical and horizontal directions.
The peel strength was greater with medium or large bonding than with small bonding. A medium or large bonding is preferred over a small bonding to prevent delamination between the textile layer and the resin layer in stretch use. This is because if the resin layer peels off from the textile layer, the circuit on the resin may come into contact with an unintended object when the product is produced, resulting in damage to the circuit and electrical problems.

Although the present invention has been illustrated using the preferred embodiment of the invention as described above, the invention should not be construed as being limited to this embodiment. It is understood that the invention is to be construed in scope only by the claims. It is understood that a person skilled in the art can implement an equivalent range from the description of specific preferred embodiments of the present invention based on the description of the present invention and common technical knowledge. It is understood that the documents cited herein are to be incorporated by reference herein in the same manner as if the contents themselves were specifically set forth herein.

In the field of circuit boards, the present invention suppresses deterioration in stretchability of the circuit board due to curing of the adhesive layer that bonds the textile layer and the resin layer, and provides sufficient stretchability (for example, 50 of about 1.0 or less). % modulus) to obtain a circuit board.

1 Circuit Board 10, 10a to 10h Circuit Pattern 11, 12 Electrode Pad 13a to 13d Wiring 100 Elastic Base Material 110 Textile Layer 110a Fiber Mass Portion 120 Resin Layer 130 Adhesion Portion 130a Welding Portion M Printing Table Ma Mask Member P Screen Printing Machine Pf Frame Pe Print paste Ps Screen member Ps0 Screen opening Sq Squeeze

Claims (16)

(1) A stretchable base material,
a textile layer;
a resin layer covering the textile layer;
a stretchable base material comprising an adhesive layer including a plurality of adhesive portions for bonding the textile layer and the resin layer;
(2) A circuit board including a circuit pattern formed by printing on the surface of the resin layer,
The elastic modulus of the adhesive layer is lower than the elastic modulus of the resin layer,
a peel strength of at least about 180 g/cm or greater and a 50% modulus of about 1.0 or less, wherein the 50% modulus is defined by "50% modulus = load at 50% elongation (MPa)"; circuit board. 2. The circuit board according to claim 1, wherein said plurality of bonding portions are arranged independently of said circuit pattern. 3. The circuit board according to claim 1 or 2, wherein a distance between adjacent ones of said plurality of bonded portions is about 0.7 mm to about 2.0 mm. 4. The circuit board according to any one of claims 1 to 3, wherein the ratio of the total area of the plurality of bonding 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 the area of each of said plurality of bonds is between about 0.4 mm ² and about 1.8 mm ² . 6. The circuit board according to claim 5, wherein said plurality of adhesive portions are substantially circular. 7. The circuit board of claim 6, wherein the adhesive portion has a diameter of about 0.7 mm to about 1.5 mm. The circuit board of any one of claims 1-7, having a peel strength of at least about 700 g/cm or greater. The circuit board according to any one of claims 1 to 8, wherein the stretchable substrate has a thickness of about 0.25 mm to about 1.0 mm. The circuit board according to any one of claims 1 to 9, wherein the circuit pattern has a thickness of 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 from a conductive composition containing silver. 12. The circuit board of Claim 11, wherein the conductive composition further comprises a stretchable material. 3. The circuit board according to claim 1, wherein said resin layer contains a thermoplastic resin material. A product comprising a circuit board according to any one of claims 1-13. 5. The product of claim 4, wherein said product is selected from the group consisting of clothing, shoes, footwear, gloves, toys, vehicle seats, healthcare equipment and vehicle steering. (1) A stretchable base material,
a textile layer;
a resin layer covering the textile layer;
an adhesive layer including a plurality of adhesive portions that adhere the textile layer and the resin layer;
a stretchable base material comprising
(2) a circuit pattern formed by printing on the surface of the resin layer;
A circuit board comprising
The distance between adjacent bonded portions among the plurality of bonded portions is about 0.7 mm to about 2.0 mm,
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%,
The diameter of the bonding portion is about 0.7 mm to about 1.5 mm,
The elastic base material has a thickness of about 0.25 mm to about 1.0 mm,
a peel strength of at least about 180 g/cm or greater and a 50% modulus of about 1.0 or less, wherein the 50% modulus is defined by "50% modulus = load at 50% elongation (MPa)"; circuit board.

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