JP6772448B2 - Conductive resin compositions, wiring, wiring boards and electronics - Google Patents

Description

The present invention relates to conductive resin compositions, wirings, wiring boards and electronic devices.

In recent years, the development of wearable devices that can be worn on the human body and the like has been actively carried out, and in connection with this, the development of elastic wiring or wiring boards has been actively carried out.

In this regard, the techniques described in Patent Document 1 or Patent Document 2 are known. Patent Document 1 includes, as an elastic wiring board, an elastic base material made of a first elastomer and an elastic wiring containing a conductive filler and a second elastomer, and the elastic base material and the elastic base material are expanded and contracted. A wiring board in which an elastic adhesion layer is formed between the sex wiring and the sex wiring is disclosed. Further, according to the description of Patent Document 1, it is shown that by adopting such a configuration, excellent reliability as an elastic wiring board is exhibited.

Further, Patent Document 2 includes a conductive layer having an elastomer, a conductive material filled in the elastomer, and a protective layer made of an elastomer arranged so as to cover the conductive layer. The conductive film is disclosed. According to the description of Patent Document 2, it is shown that the electric resistance of the conductive film is unlikely to increase even if it is stretched, and there is little possibility of breakage.

Japanese Unexamined Patent Publication No. 2014-151617 JP-A-2010-153821

The techniques disclosed in Patent Document 1 and Patent Document 2 improve the durability of the wiring board as a whole by arranging the resin material having elasticity and conductivity so as to be in contact with other materials. It can be said that.
However, in the recent wearable device market, there is an increasing demand for further miniaturization of the entire device, and there are restrictions on increasing the types of materials for the entire wiring board and complicating the structure. is there. That is, from such a technical background, there is a demand for improving the durability of the conductive resin composition as a cured product itself.

The present invention has been made in view of the above circumstances, and provides a conductive resin composition having excellent durability as a cured product.

As a result of diligent studies by the present inventors, when a specific extension / release test is performed on a cured product of the conductive resin composition, the conductive resin composition dramatically changes by satisfying a certain condition of resistance value behavior. It has been found that the durability of a cured product can be exhibited.

That is, according to the present invention.
A conductive resin composition containing (A) an elastomer and (B) a metal powder, which is used to form a resin material having elasticity and conductivity.
(C) comprises silica particles, the specific surface area of the (C) silica particles is ^{10m 2} / ^g~400m 2 / g,
The content of the silica particles (C) is 2% by mass or more and 10% by mass or less with respect to the total solid content of the conductive resin composition.
Contains solvent,
When the test shown below is performed 100 times,
The average value R _top10 of the peak top of the resistance value that occurs from the start of the 6th to the 10th extension to the end of the release is the peak top of the resistance value that occurs from the start of the 1st to the 5th extension to the end of the release. _Provided is a conductive resin composition characterized by having an average value of R _top 5 or less.
(test)
Wiring composed of a cured product of the conductive resin composition having a length of 30 mm, a width of 500 μm, and a height of 50 μm on a substrate made of silicone rubber having a length of 5 cm, a width of 2 cm, and a height of 500 μm and a hardness of 30. The pattern is formed so that the center point of the surface composed of the length direction and the width direction side of the substrate and the center point of the surface composed of the length direction and the width direction side of the wiring pattern overlap. Use as a test piece.
This test piece is stretched by 20% in the length direction in 3 seconds while measuring resistance, held for 10 seconds, released from the stretch in 3 seconds, and held for 10 seconds.

Further, according to the present invention, a wiring composed of a cured product of the above conductive resin composition is provided.

Further, according to the present invention, a wiring board including the above wiring and a board is provided.

Further, according to the present invention, an electronic device including the above wiring board is provided.

According to the present invention, it is possible to provide a conductive resin composition having excellent durability as a cured product. The cured product of such a conductive resin composition has excellent resistance at the time of expansion and contraction release, and can be preferably used for applications of devices that are repeatedly expanded and contracted.

It is sectional drawing which shows the outline of the electronic apparatus in this embodiment. It is a chart which shows the result of having measured the resistance value about the test piece using the conductive resin composition of Example 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by the same reference numerals, and description thereof will be omitted as appropriate. Further, in the present specification, "~" means the following from the above unless otherwise specified.

[Conductive resin composition]
First, an outline of the conductive resin composition in the present embodiment will be described. That is, the conductive resin composition of the present embodiment is shown below.
A conductive resin composition containing (A) an elastomer and (B) a metal powder.
When the test shown below is performed 100 times,
The average value R _top10 of the peak top of the resistance value that occurs from the start of the 6th to the 10th extension to the end of the release is the peak top of the resistance value that occurs from the start of the 1st to the 5th extension to the end of the release. A conductive resin composition characterized by having an average value of R _top 5 or less.
(test)
Wiring composed of a cured product of the conductive resin composition having a length of 30 mm, a width of 500 μm, and a height of 50 μm on a substrate made of silicone rubber having a length of 5 cm, a width of 2 cm, and a height of 500 μm and a hardness of 30. The pattern is formed so that the center point of the surface composed of the length direction and the width direction side of the substrate and the center point of the surface composed of the length direction and the width direction side of the wiring pattern overlap. Use as a test piece.
This test piece is stretched by 20% in the length direction in 3 seconds while measuring resistance, held for 10 seconds, released from the stretch in 3 seconds, and held for 10 seconds.

That is, the conductive resin composition of the present embodiment satisfies a specific condition when a test piece having a specific size is prepared and the stretching / releasing test is repeated. The present inventors have found that when the cured product satisfies a specific condition in this way, the cured product can sufficiently withstand the use of wiring in which the cured product is repeatedly expanded and contracted.

That is, in the above test, the test of extending the test piece by 20% in 3 seconds in the length direction of the test piece and releasing the extension in 3 seconds is repeated, and the extension is started and released. At the start, the resistance of the test piece temporarily increases sharply. In the present embodiment, focusing on the peak top when this resistance suddenly increases, the average of the peak tops of the resistance values generated from the start of the extension to the end of the release at the beginning of the test (that is, from the first to the fifth). value R _top5 is, the stage where a certain period of time has elapsed from the test start step (i.e., the sixth 10th) to a value close to the average value R _top10 peak top of the resistance value occurring in the elongation start until the release end of the It has been found that the durability of the conductive resin composition as a cured product can be exhibited by this control.
Further, an aspect of the conductive resin composition of the present embodiment is that the wiring pattern provided on the test piece is not broken even if this test is repeated at least 100 times.
In such a test, the resistance value can be measured by using a DC voltage / power flow / monitor (6241A) manufactured by ADC Co., Ltd.
Further, as the silicone rubber used as the substrate, a silicone rubber having a hardness of "30" at 25 ° C. measured by a type A durometer defined in JIS K6253 is used.

Further, as a curing condition for performing such a test, a curing condition in which the conductive resin composition is applied to the condition of 170 ° C. for 60 minutes can be adopted.

In the present embodiment, the _{R top10 is} set to less than twice the _{R top5,} preferably not more than 1.8 times, more preferably 1.5 times or less. The upper limit of the magnification of the R _top10 for R _top5 By setting like this, the cured product is achieved to withstand repeated expansion and contraction.
Although the lower limit of the ratio of _{R top10} is not particularly limited to this _{R top5,} for example, 1.05 times or more.

The value of R _{top 10} can be appropriately set according to the type of metal powder or elastomer used, but can be, for example, 1.2 Ω or more, 0.12 Ω or more, or 0.12 Ω or more. It can be 0.012Ω or more.
The value of R _{top 10} is, for example, 750 Ω or less, more preferably 700 Ω or less, and further preferably 600 Ω or less.

The value of R _{top 5} can also be set as appropriate, but can be, for example, 1.2 Ω or more, 0.12 Ω or more, or 0.012 Ω or more.
The value of R _{top 5} is, for example, 700 Ω or less, more preferably 650 Ω or less, and further preferably 600 Ω or less.

Moreover, it is preferable that the conductive resin composition of the present embodiment satisfies the following characteristics when the same test is performed.
That is, in the conductive resin composition of the present embodiment, when the test is performed 100 times, the resistance value R _re50 at the end of the 50th extension / release becomes the resistance value R at the end of the 5th extension / release. It is preferably 5 times or less of _re5 .

In the above test, the resistance value temporarily increases sharply at the stage of starting extension or release, but after a certain period of time has passed after this extension or release, it converges to a certain value. Become. In the present specification, the resistance value at this converged stage is referred to as "resistance value at the end of extension" or "resistance value at the end of extension release".

In the present embodiment, the test piece satisfies the condition that "the resistance value R _re50 at the end of the 50th extension release is 5 times or less than the resistance value R _re5 at the end of the 5th extension release". As a result, a conductive resin composition having further excellent durability as a cured product can be achieved.
In the present embodiment, the R _re50 is preferably 5 times or less of R _re5 , more preferably 4 times or less, further preferably 3 times or less, and particularly preferably 2 times or less.
By setting the upper limit of the magnification of R _{re50 with} respect to R _re5 in this way, a cured product that can withstand repeated expansion and contraction is achieved.
The lower limit of the magnification of R _{re50 with} respect to R _re5 is not particularly limited, but is, for example, 1.05 times or more.

The value of R _re50 can be appropriately set according to the type of metal powder or elastomer used, but can be, for example, 12Ω or more, 1.2Ω or more, or 0. It can be 12Ω or more.
The value of R _re50 is, for example, 800 Ω or less, more preferably 750 Ω or less, and further preferably 700 Ω or less.

The value of R _re5 can also be set as appropriate, but can be, for example, 1.2 Ω or more, 0.12 Ω or more, or 0.012 Ω or more.
_Further, the value of R _re5 is, for example, 600 Ω or less, more preferably 500 Ω or less, and further preferably 400 Ω or less.

Moreover, it is preferable that the conductive resin composition of the present embodiment satisfies the following characteristics when the above-mentioned test is performed.
That is, in the conductive resin composition of the present embodiment, when the test is performed 100 times, the resistance value R _ex100 at the end of the 100th extension and the resistance value R _re 100 at the end of the 100th extension release are _obtained. It is preferably 4 times or less of.

In the present embodiment, when _Rex100 is at a constant magnification of _Rre100 or less, the desired electrical resistance can be maintained even after repeated use, so that the life of the electronic device or the like can be extended.
In the present embodiment, this _Rex100 is preferably 4 times or less, more preferably 3 times or less, still more preferably 2 times or less of _Rre100 . By setting the upper limit of the magnification of _{Rex100 with} respect to _Rre100 in this way, a cured product that further contributes to the extension of the life of the electronic device or the like is achieved.
The lower limit of the magnification of _{Rex100 with} respect to _Rre100 is not particularly limited, but is, for example, 0.2 times or more. Depending on the composition of the conductive resin composition, _Rex100 may take a lower value than _Rre100 . This is because the wiring is compressed in the width direction and the thickness direction by the elongation, so that the dispersed metal powders come into contact with each other, and as a result, a dispersed state in which the conductivity is improved can be obtained.

The value of _Rex100 can be appropriately set according to the type of metal powder or elastomer used, but can be, for example, 24Ω or more, 2.4Ω or more, or 0. It can be 24Ω or more.
_Further, the value of _Rex100 is, for example, 950Ω or less, more preferably 900Ω or less, and further preferably 800Ω or less.

The value of R _re100 can be appropriately set according to the type of metal powder or elastomer used, but can be, for example, 12Ω or more, 1.2Ω or more, or 0. It can be 12Ω or more.
The value of R _re100 is, for example, 850 Ω or less, more preferably 800 Ω or less, and further preferably 700 Ω or less.

The numerical values under each of the above conditions can be set to desired values by appropriately adjusting, for example, the type and blending ratio of each component contained in the conductive resin composition, the preparation method of the conductive resin composition, and the like. It is possible to control.
In the present embodiment, for example, using silicone rubber as the elastomer is a preferable embodiment for controlling the numerical values under each of the above conditions, and a plurality of types of vinyl group-containing organopolysiloxanes having different vinyl group contents are used. Inclusion may be selected as an example of a particularly preferred embodiment from the viewpoint of controlling these numerical ranges within a desired range.

Subsequently, each composition constituting the conductive resin composition of the present embodiment will be described.

((A) Elastomer)
The conductive resin composition of the present embodiment contains (A) an elastomer. As a result, even when the conductive resin composition is made into a cured product, it is possible to exhibit appropriate elasticity.
As the elastomer (A), known elastomers can be adopted, and for example, silicone rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber and the like can be used.
Among these, it is preferable to contain silicone rubber from the viewpoint of being chemically stable and having excellent mechanical strength.
Hereinafter, the description will be continued by taking the case where silicone rubber is used as the elastomer (A) as an example.

As the silicone rubber, for example, one having a siloxane structure in the molecule is used.
In the present embodiment, among such silicone rubbers, a silicone rubber obtained from a mixture of a vinyl group-containing linear organopolysiloxane (A-1) and an organohydrogenpolysiloxane (A-2) is preferable. Used.

<Vinyl group-containing linear organopolysiloxane (A-1)>
The vinyl group-containing linear organopolysiloxane (A-1) has a linear structure and contains a vinyl group, and the vinyl group serves as a cross-linking point at the time of curing.

The content of the vinyl group of the vinyl group-containing linear organopolysiloxane (A-1) is not particularly limited, but is preferably 0.01 to 15 mol%, preferably 0.05 to 12 mol%. Is more preferable. As a result, the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A-1) is optimized, and a network with each component can be reliably formed.

In the present specification, the vinyl group content is the molar amount of the vinyl group-containing siloxane unit when all the units constituting the vinyl group-containing linear organopolysiloxane (A-1) are 100 mol%. %. However, the calculation is performed assuming that there is one vinyl group for each vinyl group-containing siloxane unit.

The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A-1) is not particularly limited, but is preferably in the range of 3000 to 10000, more preferably 4000 to 8000.

Further, the specific gravity of the vinyl group-containing linear organopolysiloxane (A-1) is not particularly limited, but is preferably in the range of about 0.9 to 1.1.

By using a vinyl group-containing linear organopolysiloxane (A-1) having a degree of polymerization and specific gravity within the above range, the conductive resin composition obtained has heat resistance and flame retardancy. It is possible to improve the chemical stability and the like.

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

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

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

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

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

In the formula (1), a plurality of R ¹ is independent from each other, may be different from each other, it may be the same. The same applies to R ² and R ³ .

Further, m and n are the number of repeating units constituting the vinyl group-containing linear organopolysiloxane (A-1) represented by the formula (1), m is an integer of 1 to 1000, and n is 3000. It is an integer of 10000. m is preferably 40 to 700, and n is preferably 3600 to 8000.

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

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

Further, as the vinyl group-containing linear organopolysiloxane (A-1) as described above, the first vinyl group-containing linear organopoly having a vinyl group content of 0.05 to 0.2 mol%. A siloxane (A-1 (a)) containing a second vinyl group-containing linear organopolysiloxane (A-1 (b)) having a vinyl group content of 0.5 to 12 mol%. Is preferable. (A) As the elastomer, a first vinyl group-containing linear organopolysiloxane (A-1 (a)) having a general vinyl group content and a second vinyl group-containing direct link having a high vinyl group content. By combining with a chain organopolysiloxane (A-1 (b)), the vinyl groups can be unevenly distributed, and the cross-linking density can be more effectively formed in the cross-linking network of the silicone rubber. it can. As a result, the tear strength of the silicone rubber can be increased more effectively. Further, this makes it possible to dramatically improve the durability of the conductive resin composition as a cured product.

Specifically, as the vinyl group-containing linear organopolysiloxane (A-1), for example, in the above formula (1-1), the unit in which R ¹ is a vinyl group and / or R ² is a vinyl group. A first vinyl group-containing linear organopolysiloxane (A-1 (a)) containing 0.05 to 0.2 mol% of units, and a unit in which R ¹ is a vinyl group and / or R ² is vinyl. It is preferable to use a second vinyl group-containing linear organopolysiloxane (A-1 (b)) containing 0.5 to 12 mol% as the unit as the group.

Further, the first vinyl group-containing linear organopolysiloxane (A-1 (a)) preferably has a vinyl group content of 0.1 to 0.15 mol%. The vinyl group-containing linear organopolysiloxane (A-1 (b)) preferably has a vinyl group content of 0.8 to 8.0 mol%.

Further, when the first vinyl group-containing linear organopolysiloxane (A-1 (a)) and the second vinyl group-containing linear organopolysiloxane (A-1 (b)) are blended in combination. , (A-1 (a)) and (A-1 (b)) are not particularly limited, but usually (A-1 (a)) :( A-1 (b)) is 1 in terms of mass ratio. : 0.05 to 1: 0.6 is preferable, and 1: 0.08 to 1: 0.5 is more preferable.

As the first and second vinyl group-containing linear organopolysiloxanes (A-1 (a)) and (A-1 (b)), only one type may be used, or two or more types may be used. May be used in combination.

<Organohydrogenpolysiloxane (A-2)>
Organohydrogenpolysiloxane (A-2) is a linear organohydrogenpolysiloxane (A-2 (a)) having a linear structure and a branched organohydrogenpolysiloxane (A-2 (A-2)) having a branched structure. It is classified into b)), and in this embodiment, only the linear organohydrogenpolysiloxane (A-2 (a)) may be used, or only the branched organohydrogenpolysiloxane (A-2 (b)) may be used. Alternatively, both of these linear organohydrogenpolysiloxanes (A-2 (a)) and branched organohydrogenpolysiloxanes (A-2 (b)) may be contained.

The linear organohydrogenpolysiloxane (A-2 (a)) has a linear structure and a structure in which hydrogen is directly bonded to Si (≡Si—H), and is a vinyl group-containing linear structure. In addition to the vinyl group of the organopolysiloxane (A-1), it is a polymer that acts on the reactive groups of the components blended in the conductive resin composition and crosslinks these components.

The molecular weight of the linear organohydrogenpolysiloxane (A-2 (a)) is not particularly limited, but the weight average molecular weight is preferably 20000 or less, and more preferably 1000 or more and 10000 or less.

The weight average molecular weight of the linear organohydrogenpolysiloxane (A-2 (a)) can be measured by GPC (gel permeation chromatography).

Further, the linear organohydrogenpolysiloxane (A-2 (a)) preferably does not have a vinyl group. As a result, it is possible to accurately prevent the cross-linking reaction from proceeding in the molecule of the linear organohydrogenpolysiloxane (A-2 (a)).

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

In the formula (2), R ⁴ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, a hydrocarbon group combining these, or a hydride group. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group and the like, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

Also, R ⁵ is a hydrocarbon group or a hydride group, in combination a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, an alkenyl group, an aryl group, these. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group and a propyl group, and among them, a methyl group is preferable. Examples of the alkenyl group having 1 to 10 carbon atoms include a vinyl group, an allyl group, a butenyl group and the like. Examples of the aryl group having 1 to 10 carbon atoms include a phenyl group.

In the formula (2), a plurality of R ⁴ are independent from each other, may be different from each other, it may be the same. The same is true for R ^5. However, of the plurality of R ⁴ and R ⁵ , at least two or more are hydride groups.

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

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

Further, m and n are the number of repeating units constituting the linear organohydrogenpolysiloxane (A-2 (a)) represented by the formula (2), and m is an integer of 2 to 500 and n. Is an integer of 2 to 400, and 20 ≦ m + n ≦ 500. Preferably, m is 2 to 300, n is 2 to 200, and is an integer of 40 ≦ m + n ≦ 300.

As the linear organohydrogenpolysiloxane (A-2 (a)), only one type may be used alone, or two or more types may be used in combination.

Since the branched organohydrogenpolysiloxane (A-2 (b)) has a branched structure, it forms a region having a high crosslink density, and is a component that greatly contributes to the formation of a sparsely packed structure with a crosslink density in the silicone rubber system. is there. Further, like the linear organohydrogenpolysiloxane (A-2 (a)), it has a structure (≡Si—H) in which hydrogen is directly bonded to Si, and is a vinyl group-containing linear organopolysiloxane (A). In addition to the vinyl group of -1), it is a polymer that acts on the reactive groups of each component blended in the conductive resin composition and crosslinks these components.

The specific gravity of the branched organohydrogenpolysiloxane (A-2 (b)) is in the range of 0.9 to 0.95.

Further, the branched organohydrogenpolysiloxane (A-2 (b)) usually preferably has no vinyl group. As a result, it is possible to accurately prevent the cross-linking reaction from proceeding in the molecule of the branched organohydrogenpolysiloxane (A-2 (b)).

Further, as the branched organohydrogenpolysiloxane (A-2 (b)), those represented by the following average composition formula (c) are preferable.

Average composition formula (c)
^{_{(H a (R 7) 3}} -a SiO 1/2) m (SiO 4/2) n
(In the formula (c), ^{R 7} is a monovalent organic group, a is 1 to 3 in the range of integers, m is ^{_{H a (R 7) 3-}} a number of _{SiO 1/2} units, n represents SiO _{4 /} It is a number of ₂ units).

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

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

Further, in the equation (c), m is ^{_{H a (R 7) 3-}} a number of _{SiO 1/2} units, n is the number of _{SiO 4/2} units.

The branched organohydrogenpolysiloxane (A-2 (b)) has a branched structure. The linear organohydrogenpolysiloxane (A-2 (a)) and the branched organohydrogenpolysiloxane (A-2 (b)) differ in that their structures are linear or branched, and Si. The number of alkyl groups R (R / Si) bonded to Si when the number of is 1 is 1.8 to 2.1 for the linear organohydrogenpolysiloxane (A-2 (a)), which is branched. In the form of organohydrogenpolysiloxane (A-2 (b)), the range is 0.8 to 1.7.

Since the branched organohydrogenpolysiloxane (A-2 (b)) has a branched structure, for example, a residue when heated to 1000 ° C. at a heating rate of 10 ° C./min under a nitrogen atmosphere. The amount will be 5% or more. On the other hand, since the linear organohydrogenpolysiloxane (A-2 (a)) is linear, the amount of residue after heating under the above conditions is almost zero.

Further, as a specific example of the branched organohydrogenpolysiloxane (A-2 (b)), those having a structure represented by the following formula (3) can be mentioned.

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

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

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

As the branched organohydrogenpolysiloxane (A-2 (b)), only one type may be used alone, or two or more types may be used in combination.

In the linear organohydrogenpolysiloxane (A-2 (a)) and the branched organohydrogenpolysiloxane (A-2 (b)), the amount of hydrogen atoms (hydride groups) directly bonded to Si is , Each is not particularly limited. However, in the present embodiment, for 1 mol of the vinyl group in the vinyl group-containing linear organopolysiloxane (A-1), the linear organohydrogenpolysiloxane (A-2 (a)) and the branched organo are branched. The total amount of hydride groups of the hydrogen polysiloxane (A-2 (b)) is preferably 0.5 to 5 mol, more preferably 1 to 3.5 mol. As a result, the linear organohydrogenpolysiloxane (A-2 (a)) and the branched organohydrogenpolysiloxane (A-2 (b)) and the vinyl group-containing linear organopolysiloxane (A-1) ), A bridged network can be reliably formed.

Further, the linear organohydrogenpolysiloxane (A-2 (a)) and the branched organohydrogenpolysiloxane (A-2 (b)) are usually composed of a linear organohydrogenpolysiloxane (A-). 2 (a)) is contained as a main agent, and the branched organohydrogenpolysiloxane (A-2 (b)) is added when the silicone rubber is formed with a region having a higher crosslink density, as described above. .. Therefore, when the linear organohydrogenpolysiloxane (A-2 (a)) and the branched organohydrogenpolysiloxane (A-2 (b)) are combined and blended, (A-2 (a)). The ratio of (A-2 (b)) to (A-2 (b)) is preferably (A-2 (a)) :( A-2 (b)) by weight, preferably 1: 0.1 to 1: 1. It is set to 1: 0.2 to 1: 0.5.

In the present embodiment, the content of the elastomer (A) in the conductive resin composition is preferably 5% by mass or more, preferably 7% by mass or more, based on the total solid content of the conductive resin composition. More preferably, it is more preferably 10% by mass or more. The content of the elastomer (A) in the conductive resin composition is preferably 30% by mass or less, more preferably 25% by mass or less, based on the total solid content of the conductive resin composition. It is preferably 20% by mass or less, and more preferably 20% by mass or less.
By setting the content of the elastomer (A) to the above lower limit value or more, the cured product of the conductive resin composition can have appropriate flexibility. Further, by setting the content of the elastomer (A) to the above upper limit value or less, the mechanical strength of the cured product can be improved.
In the present specification, the “solid content” refers to the entire component from which volatile components such as water and organic solvent have been removed, and for example, a component that does not volatilize even if it is liquid at room temperature. , Add up as solid content.
The same applies to each component below.

((B) Metal powder)
The conductive resin composition of the present embodiment contains (B) metal powder.
The metal constituting the (B) metal powder is not particularly limited, but for example, at least one of copper, silver, gold, nickel, tin, lead, zinc, bismuth, antimon, or an alloy of these metal powders. , Or two or more of these can be included.
Of these, the metal powder (B) preferably contains silver or copper, that is, silver powder or copper powder, because of its high conductivity and high availability.
As these (B) metal powders, those coated with other kinds of metals can also be used.

In the present embodiment, the shape of the metal powder (B) is not limited, but conventionally used metal powders such as dendritic, spherical, and flaky can be used.
In addition, (B) The particle size of the metal powder is also not limited, for example, is preferably at least 0.001μm with an average particle diameter _{D 50,} and more preferably 0.01μm or more, more preferably 0.1μm or more is there. (B) of the metal powder particle size, for example, is preferably 1,000μm less in average particle diameter _{D 50,} more preferably 100μm or less, more preferably 20μm or less.
By setting the average particle size D ₅₀ in such a range, it is possible to exhibit appropriate conductivity as a cured product of the conductive resin composition.
The particle size of the metal powder (B) is, for example, the average value of 200 metal powders arbitrarily selected by observing the conductive resin composition or its cured product with a transmission electron microscope or the like and performing image analysis. Can be defined as.

In the present embodiment, the content of the metal powder (B) in the conductive resin composition is preferably 60% by mass or more, preferably 65% by mass or more, based on the total solid content of the conductive resin composition. It is more preferable that the amount is 70% by mass or more. The content of the metal powder (B) in the conductive resin composition is preferably 90% by mass or less, and preferably 88% by mass or less, based on the total solid content of the conductive resin composition. More preferably, it is 85% by mass or less.
By setting the content of the metal powder (B) to the above lower limit value or more, the cured product of the conductive resin composition can have appropriate conductive properties. Further, by setting the content of the metal powder (B) to the above upper limit value or less, the cured product can have appropriate flexibility.

((C) Silica particles)
The conductive resin composition of the present embodiment may contain (C) silica particles, if necessary. By including the silica particles (C), the hardness and mechanical strength of the cured product formed from the conductive resin composition can be improved.

The (C) silica particles is preferably a specific surface area of 10 to 400 m ² / g, and more preferably 20 to 400 m ² / g. The average particle size D ₅₀ is preferably 1 to 100 nm, more preferably 5 to 20 nm.

By using the silica particles (C) that are within the range of the specific surface area and the average particle size, the above-mentioned function as the silica particles (C) can be remarkably exhibited.
The particle size of the silica particles (C) is, for example, the average value of 200 silica particles arbitrarily selected by observing the conductive resin composition or its cured product with a transmission electron microscope or the like and performing image analysis. Can be defined as.

The silica particles (C) are not particularly limited, but for example, fumed silica, calcined silica, precipitated silica and the like can be used.
As the silica particles (C), only one type may be used alone, or two or more types may be used in combination.

In the present embodiment, the content of the silica particles (C) in the conductive resin composition is preferably 2% by mass or more, preferably 3% by mass or more, based on the total solid content of the conductive resin composition. It is more preferable that the amount is 4% by mass or more. The content of the (C) silica particles in the conductive resin composition is preferably 15% by mass or less, and preferably 12% by mass or less, based on the total solid content of the conductive resin composition. More preferably, it is 10% by mass or less.
By setting the content of the silica particles (C) to the above lower limit value or more, the cured product of the conductive resin composition can have an appropriate mechanical strength. Further, by setting the content of (C) silica particles to the above upper limit value or less, the cured product can have appropriate conductive properties.

((D) Silane coupling agent)
The conductive resin composition of the present embodiment may contain (D) a silane coupling agent. This (D) silane coupling agent has a hydrolyzable group, and this hydrolyzable group is hydrolyzed by water to become a hydroxyl group, and this hydroxyl group undergoes a dehydration condensation reaction with the hydroxyl group on the surface of (C) silica particles. By doing so, (C) the surface of the silica particles can be modified.
In addition, even when (C) silica particles are not present, the effect of improving the adhesion between the wiring composed of the cured product of the conductive resin composition and the substrate on which the wiring is drawn is exhibited. Can be done.

Further, as this (D) silane coupling agent, one having a hydrophobic group can be used. As a result, this hydrophobic group is imparted to the surface of the (C) silica particles, so that the cohesive force of the (C) silica particles is reduced in the conductive resin composition, and as a result, the silica in the composition is reduced. The dispersibility of particles is improved. As a result, the mechanical strength of the cured product of the conductive resin composition is further improved.

Further, the (D) silane coupling agent preferably has a vinyl group. As a result, when (C) silica particles are used, a vinyl group is introduced on the surface thereof.
As a result, for example, when the (A) elastomer contains a vinyl group-containing linear organopolysiloxane (A-1) and an organohydrogenpolysiloxane (A-2), the following effects are obtained. ..
That is, when the conductive resin composition is cured, that is, the vinyl group contained in the vinyl group-containing linear organopolysiloxane (A-1) and the hydride group contained in the organohydrogenpolysiloxane (A-2) are formed. When a network (crosslinked structure) is formed by the hydrosilylation reaction, the vinyl group of the (C) silica particles is also a hydrosilylation reaction with the hydride group of the organohydrogenpolysiloxane (A-2). (C) Silica particles are also incorporated into the network because they are involved in. As a result, it is possible to increase the hardness and the modulus of the formed cured product.

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

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

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

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

Further, examples of the hydrolyzable group include an alkoxy group such as a methoxy group and an ethoxy group, a chloro group or a silazane group. Those having a silazane group as a hydrolyzable group have two structures of (Yn−Si−) in the above formula (4) due to their structural characteristics.

Specific examples of the silane coupling agent (D) represented by the above formula (4) include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, and methyltri, as those having a hydrophobic group as a functional group. Ekoxysilanes such as ethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane; methyltrichlorosilane , Chlorosilanes such as dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane; hexamethyldisilazane, examples of which have a vinyl group as a functional group include methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, and methaloxy. Ekoxysilanes such as propylmethyldiethoxysilane, metharoxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane, vinylmethyldichlorosilane; divinyltetramethyldi Examples thereof include silazanes, but in consideration of the above description, hexamethyldisilazane is particularly preferable as having a hydrophobic group, and divinyltetramethyldisilazane is preferable as having a vinyl group.

In the present embodiment, the content of the (D) silane coupling agent in the conductive resin composition is preferably 0.1% by mass or more with respect to the total solid content of the conductive resin composition, and is 0. It is more preferably 3% by mass or more, and further preferably 0.5% by mass or more. The content of the (D) silane coupling agent in the conductive resin composition is preferably 5% by mass or less, preferably 4% by mass or less, based on the total solid content of the conductive resin composition. More preferably, it is more preferably 3% by mass or less.
When the content of the (D) silane coupling agent is set to the above lower limit value or more, the cured product of the conductive resin composition has appropriate adhesion to the substrate, and (C) silica particles are used. Can contribute to the improvement of the mechanical strength of the cured product as a whole. Further, by setting the content of the (D) silane coupling agent to the above upper limit value or less, the cured product can have an appropriate conductive property.

((E) Platinum or platinum compound)
The conductive resin composition of the present embodiment may contain (E) platinum or a platinum compound.
(E) Platinum or a platinum compound is a component that acts as a catalyst during curing of the conductive resin composition of the present embodiment.

As the platinum or platinum compound, known ones can be used, for example, platinum black, platinum supported on silica, carbon black or the like, chloroplatinic acid or an alcohol solution of chloroplatinic acid, chloride. Examples thereof include a complex salt of platinum acid and olefin, and a complex salt of platinum chloride acid and vinyl siloxane.
As the platinum (E) platinum or platinum compound, only one type may be used alone, or two or more types may be used in combination.

In the present embodiment, the content of (E) platinum or the platinum compound in the conductive resin composition is preferably 0.0005% by mass or more with respect to the total solid content of the conductive resin composition, and is 0. It is more preferably .001% by mass or more, and further preferably 0.003% by mass or more. The content of (E) platinum or the platinum compound in the conductive resin composition is preferably 1% by mass or less, preferably 0.5% by mass or less, based on the total solid content of the conductive resin composition. Is more preferable, and 0.1% by mass or less is further preferable.
By setting the content of (E) platinum or the platinum compound to the above lower limit value or more, the conductive resin composition can be cured at an appropriate rate. Further, by setting the content of (E) platinum or the platinum compound to the above upper limit value or less, it is possible to contribute to the cost reduction when producing the conductive resin composition.

((F) water)
Further, the conductive composition of the present embodiment may contain (F) water.
As a result, the above-mentioned (D) silane coupling agent is hydrolyzed, and the desired effect is easily exhibited.
The amount of water (F) added is arbitrary.

(Other ingredients)
Further, the conductive resin composition of the present embodiment may contain known components to be blended in the resin composition in addition to the above components (A) to (F). For example, diatomaceous earth, iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide, cerium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, glass wool, mica and the like can be mentioned. In addition, dispersants, pigments, dyes, antistatic agents, antioxidants, flame retardants, thermal conductivity improvers and the like can be appropriately blended.
Further, as will be described later, a reaction inhibitor can be appropriately added from the viewpoint of controlling the curability of the conductive resin composition.

(Manufacturing method of conductive resin composition)
Subsequently, a method for producing the conductive resin composition according to the present embodiment will be described.
The conductive resin composition of the present embodiment can be produced, for example, by undergoing the following steps.

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

This kneaded product is obtained by kneading a vinyl group-containing linear organopolysiloxane (A-1) and a (D) silane coupling agent in advance, and then kneading (mixing) the (C) silica particles. Is preferable. As a result, the dispersibility of the (C) silica particles is further improved.

Further, when obtaining this kneaded product, (F) water may be added to each component as needed.

Here, it is preferable that the kneading of each component goes through a first step of heating at the first temperature and a second step of heating at the second temperature. As a result, in the first step, the surface of the (C) silica particles can be surface-treated with the (D) silane coupling agent, and in the second step, the (C) silica particles and the (D) silane coupling agent. By-products produced by the reaction with can be reliably removed from the kneaded product.

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

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

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

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

[2] Next, the organohydrogenpolysiloxane (A-2) and (E) platinum or a platinum compound were weighed in a predetermined amount, and then prepared in the above step [1] using an arbitrary kneading device. By kneading these components into the kneaded product, an elastomer compound is obtained.

When kneading each of the components, the kneaded product prepared in advance in the step [1] and the organohydrogenpolysiloxane (A-2) were mixed with the kneaded product prepared in the step [1] (E). ) It is preferable to knead platinum or a platinum compound, and then knead each kneaded product. As a result, each component can be reliably dispersed.

In this step [2], the temperature at the time of kneading is preferably about 10 to 70 ° C., more preferably about 25 to 30 ° C. as the roll set temperature.
Further, the kneading time is preferably about 5 minutes to 1 hour, more preferably about 10 to 40 minutes.

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

Further, in this step [2], a reaction inhibitor such as 1-ethynyl-1-cyclohexanol may be added to the kneaded product. As a result, even if the temperature of the kneaded product is set to a relatively high temperature, the progress of the reaction of each component can be more accurately prevented or suppressed.

[3] Next, the conductive resin composition can be obtained by dissolving the elastomer compound obtained in the step [2] in a solvent and adding the (B) metal powder.
The solvent used here may be appropriately selected from the solvents capable of uniformly dissolving or dispersing the above-mentioned formulation.

Specific examples of solvents include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane and tetradecane; benzene, toluene, ethylbenzene, xylene, trifluoromethylbenzene and benzotrifluoride. Aromatic hydrocarbons such as: diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, 1,4-dioxane, 1,3-dioxane, tetrahydrofuran. Ethers such as diethyl, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane and other haloalcans; N, N-dimethylformamide, N, Carboic acid amides such as N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide can be exemplified.
As the solvent, one of these may be used alone, or two or more kinds of solvents may be mixed and used in an arbitrary ratio.

[Use]
Subsequently, a specific application of the conductive resin composition of the present embodiment will be described with reference to FIG.

The conductive resin composition of the present embodiment can be cured to form a cured product to form wiring.
FIG. 1 shows an outline of an electronic device 100 provided with such wiring as a cross-sectional view.
Here, FIG. 1 shows a part of the electronic device 100. The electronic device 100 includes a wiring board 50 and an electronic component 60, and the wiring board 50 is configured by providing the wiring 10 on the board 20.
The electronic device 100 is used, for example, as a wearable device, and is a device that is repeatedly expanded and contracted in each direction.

The wiring 10 constituting the electronic device 100 of the present embodiment is composed of a cured product of the above-mentioned conductive resin composition. The curing conditions here can be appropriately set according to the conductive resin composition used, and for example, the curing can be performed by subjecting the temperature conditions to 150 ° C. or higher and 250 ° C. or lower for 1 minute or longer and 120 minutes or shorter.
At this time, pressurization conditions can be combined as appropriate.

The wiring 10 in the present embodiment is composed of a cured product of a conductive resin composition that satisfies a specific condition when a test piece having a specific size is prepared and an extension / release test is repeated. From this, the electronic device 100 can withstand even when it is used while being deformed for a long period of time.

Further, the substrate 20 constituting the electronic device 100 of the present embodiment is usually made of a flexible material.
As this material, the same material as the above-mentioned (A) elastomer can be adopted. Specifically, silicone rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber and the like can be used, and this material can be appropriately selected depending on the application and the like.

Further, the electronic device 100 of the present embodiment includes an electronic component 60.
The electronic component 60 may be appropriately selected from known components according to the intended use. Specific examples thereof include semiconductor elements and resistors and capacitors other than semiconductor elements. Examples of semiconductor elements include transistors, diodes, LEDs, capacitors, and the like.
In the electronic device 100 of the present embodiment, the electronic device 60 is electrically connected by wiring 10.

Further, the electronic device 100 of the present embodiment may be provided with the cover material 30 as needed. By providing the cover material 30, it is possible to prevent the wiring 10 and the electronic component 60 from being damaged.
Further, since the cover material 30 follows the expansion and contraction of the substrate 20 and the wiring 10, the electronic device 100 as a whole can be expanded and contracted without bias, which can contribute to extending the life of the electronic device 100.
The cover material 30 can be made of the same material as the substrate 20.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
Hereinafter, an example of the reference form will be added.
1. 1. A conductive resin composition containing (A) an elastomer and (B) a metal powder.
When the test shown below is performed 100 times,
The average value R _top10 of the peak top of the resistance value that occurs from the start of the 6th to the 10th extension to the end of the release is the peak top of the resistance value that occurs from the start of the 1st to the 5th extension to the end of the release. A conductive resin composition characterized by having an average value of R _top 5 or less.
(test)
Wiring composed of a cured product of the conductive resin composition having a length of 30 mm, a width of 500 μm, and a height of 50 μm on a substrate made of silicone rubber having a length of 5 cm, a width of 2 cm, and a height of 500 μm and a hardness of 30. The pattern is formed so that the center point of the surface composed of the length direction and the width direction side of the substrate and the center point of the surface composed of the length direction and the width direction side of the wiring pattern overlap. Use as a test piece.
This test piece is stretched by 20% in the length direction in 3 seconds while measuring resistance, held for 10 seconds, released from the stretch in 3 seconds, and held for 10 seconds.
2. 1. 1. The conductive resin composition according to the above.
When the test was performed 100 times,
A conductive resin composition, wherein the resistance value R _re50 at the end of the 50th extension / release is 5 times or less the resistance value R _re5 at the end of the fifth extension / release .
3. 3. 1. 1. Or 2. The conductive resin composition according to the above.
When the test was performed 100 times,
The resistance value _{R ex100} during the 100 th extension ends, characterized in that the following four times the resistance value _{R Re100} at the 100th elongation release completion, the conductive resin composition.
4. 1. 1. Or 3. The conductive resin composition according to any one of the above.
The elastomer (A) is a conductive resin composition containing silicone rubber.
5. 1. 1. Or 4. The conductive resin composition according to any one of the above.
The (A) elastomer is a conductive resin composition containing (A-1) a linear group-containing linear organopolysiloxane and (A-2) an organohydrogenpolysiloxane.
6. 1. 1. Or 5. The conductive resin composition according to any one of the above.
The metal powder (B) is a conductive resin composition containing silver powder or copper powder.
7. 1. 1. Or 6. The conductive resin composition according to any one of the above.
A conductive resin composition containing 60% by mass or more and 90% by mass or less of the metal powder (B) with respect to the total solid content of the conductive resin composition.
8. 1. 1. Or 7. The conductive resin composition according to any one of the above.
(C) A conductive resin composition containing silica particles.
9. 1. 1. Or 8. The conductive resin composition according to any one of the above.
A conductive resin composition further containing (D) a silane coupling agent.
10. 1. 1. Or 9. The conductive resin composition according to any one of the above.
(E) A conductive resin composition further containing platinum or a platinum compound.
11. 1. 1. Or 10. A wiring composed of a cured product of the conductive resin composition according to any one of the above.
12. 11. A wiring board comprising the wiring and the board described in 1.
13. 12. An electronic device comprising the wiring board described in 1.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The materials used in the examples and comparative examples are as follows.

(1) First Vinyl Group-Containing Linear Organopolysiloxane (A-1 (a)): A vinyl group-containing linear organopolysiloxane synthesized according to the following formula was used.

That is, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane in a 300 mL separable flask having a cooling tube and stirring blades substituted with Ar gas, 2,4,6,8-tetramethyl 2,4,6,8- 0.086 g (0.25 mmol) of tetravinylcyclotetrasiloxane and 0.1 g of potassium silicate were added, the temperature was raised, and the mixture was stirred at 120 ° C. for 30 minutes. At this time, an increase in viscosity was confirmed.

Then, the temperature was raised to 155 ° C., and stirring was continued for 3 hours. Then, after 3 hours, 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added, and the mixture was further stirred at 155 ° C. for 4 hours.

After 4 hours, the mixture was diluted with 250 mL of toluene and washed 3 times with water. The organic layer after washing was washed several times with 1.5 L of methanol to reprecipitate and separate the oligomer and the polymer. The obtained polymer was dried under reduced pressure at 60 ° C. overnight to obtain a first vinyl group-containing linear organopolysiloxane (A-1 (a)) (vinyl group content 0.13 mol%, Mn = 277,734, Mw = 573,906, IV value (dl / g) = 0.89).

(2) Second vinyl group-containing linear organopolysiloxane (A-1 (b)): In the synthesis of (A-1 (a)) above, 2,4,6,8-tetramethyl2,4 , 6,8-Tetravinylcyclotetrasiloxane was synthesized (A-1 (b)) in the same manner as above except that 0.86 g (2.5 mmol) was used (vinyl group content 0.92 mol%). ..

(3) Linear organohydrogenpolysiloxane (A-2 (a)): Organohydrogenpolysiloxane represented by the following formula (5) (manufactured by Momentive Performance Materials Japan LLC, trade name) "88466", in equation (5), m = 14, n = 11)

(4) Branched organohydrogenpolysiloxane (A-2 (b)): Organohydrogenpolysiloxane represented by the following formula (6) (manufactured by Gelest, trade name "HQM-107", formula (6) ), The hydride molar equivalent is 7.5-9.0 (eq / kg)).

(5) Silver powder (B): manufactured by DOWA Electronics, trade name "3-8F", average particle size D ₅₀ 1.6 μm

(6) Silica particles (C): manufactured by Nippon Aerosil Co., Ltd., trade name "AEROSIL300", specific surface area: 300 m ² / g, average particle size D ₅₀ : 7 nm

(7) Silane coupling agent (D): Hexamethyldisilazane (manufactured by Gelest)

(8) Platinum compound (E): PLATINUM DIVINYLTETRAMETHYLDISILOXONE COMPLEX (in xylene) (manufactured by Gelest, trade name "SIP6831.2")

(9) Water (F): Pure water

(10) Reaction inhibitor: 1-ethynyl-1-cyclohexanol (manufactured by Tokyo Kasei Co., Ltd.)

[Preparation of conductive resin composition]
In each Example and Comparative Example 1, a predetermined amount of a vinyl group-containing linear organopolysiloxane, silica particles, a silane coupling agent, and water are weighed in parts by mass shown in Table 1, and then kneaded. A kneaded product containing each of these components was obtained by kneading with an apparatus (manufactured by Moriyama Co., Ltd., hydraulic pressure type kneader).
As the kneading conditions here, the first step was kneaded under a nitrogen atmosphere at 60 to 90 ° C. for 1 hour, and the second step was kneaded under a reduced pressure atmosphere at 160 ° C. for 1 hour.

Subsequently, the amounts of organohydrogenpolysiloxane shown in Table 1 and the platinum compound are weighed in a predetermined amount, and a kneading device (manufactured by Kansai Roll Co., Ltd., roll machine) is used to add these to the kneaded product obtained above. Ingredients were further added and kneaded. As a result, an elastomer compound was obtained.

Further, this elastomer compound was immersed in 2.33 times the amount of tetradecane, and then stirred with a rotation / revolution mixer to prepare a solution.
Each conductive resin composition was obtained by adding silver powder to this solution.
In Comparative Example 2, an elastomer compound manufactured by Toray Dow Corning Co., Ltd. (product number C6-135; referred to as “silicone elastomer compound A” in Table 1) was immersed in 2.33 times the amount of tetradecane. After that, a conductive resin composition was obtained by adding silver powder.

[Evaluation of conductive resin composition]
The obtained conductive resin composition was evaluated according to the following items.

(Measurement of resistance value)
First, using the conductive resin compositions obtained in each Example and each Comparative Example, a wiring pattern was formed on a substrate of width 2 cm × height 500 μm × length 5 cm formed of silicone rubber (hardness 30). This was drawn and cured under the conditions of 170 ° C. for 60 minutes to prepare a test piece having a wiring pattern of width 500 μm × length 30 mm × height 50 μm.
In this Example section, the substrate was produced by molding the elastomer compound used in Example 1 (the conductive resin composition of Example 1 does not contain silver powder and tetradecane).
Using a DC voltage / current source / monitor (6241A) manufactured by ADC Co., Ltd., this test piece was extended by 20% in the length direction in 3 seconds while measuring resistance, held for 10 seconds, and said in 3 seconds. The test of releasing the elongation and holding it for 10 seconds was performed 100 times.
This change in resistance was constantly monitored and analyzed during this test. The result (chart) of this monitoring in Example 1 is shown in FIG.

In Table 1, "the average value of the peak tops of the resistance values generated from the start of the 6th to the 10th extension to the end of the release" is "R _{top 10} ", and "the release ends from the start of the 1st to the 5th extension". "R _top5" the average value of the peak top of the resistance value "caused by the time,""R _RE50 the resistance" at the 50 th extended release completion "," fifth extension release resistance at the end "and" _{R RE5} "showed" a resistance "at the 100-th extension termination" _{R ex100} ", the" resistance value at the 100th elongation release end "as" _{R Re100} ".
In addition, together with this, as _{"R top10"} and the ratio of _{"R top5"} as the _"R top10 _{/ R top5", "R re50"} and _{"R re5" "R re50 / R re5"} the ratio of, "R _re100 "and the ratio of" _{R ex100} "shown as" _R ex100 _{/ R re100} ". The value of each resistance value in Table 1 is “Ω”.
It was confirmed that the test piece in Comparative Example 1 exceeded the upper limit of measurement of the resistance value (1,000 Ω) in the 17th test. Further, in the test piece in Comparative Example 2, it was confirmed that the wiring pattern was broken in the fifth test.

(Durability test)
The test piece was prepared in the same manner as the method for preparing the test piece in which the resistance value was measured for each Example and each Comparative Example.
The test piece thus obtained was stretched by 20% in the length direction of the test piece, and the operation of releasing the stretch was performed 1000 times.
◎ is the wiring that is sufficiently conductive even when this extension operation is performed 1000 times, ○ is the one that is sufficiently conductive even when the extension operation is performed 500 times, and when the extension operation is performed 500 times Those with broken wiring were evaluated as x. The results are shown in Table 1.

As shown in Table 1, the conductive resin compositions obtained in each example are excellent in durability when made into a cured product. It is expected that such a conductive resin composition can be suitably used for applications such as wearable devices.

Since the conductive resin composition of the present invention has excellent durability as a cured product, it can be preferably used for applications such as devices that are repeatedly expanded and contracted.

10 Wiring 20 Board 30 Cover material 50 Wiring board 60 Electronic components 100 Electronic devices

Claims (16)

A conductive resin composition containing (A) an elastomer and (B) a metal powder, which is used to form a resin material having elasticity and conductivity.
(C) comprises silica particles, the specific surface area of the (C) silica particles is ^{10m 2} / ^g~400m 2 / g,
The content of the silica particles (C) is 2% by mass or more and 10% by mass or less with respect to the total solid content of the conductive resin composition.
Contains solvent,
When the test shown below is performed 100 times,
The average value R _top10 of the peak top of the resistance value that occurs from the start of the 6th to the 10th extension to the end of the release is the peak top of the resistance value that occurs from the start of the 1st to the 5th extension to the end of the release. A conductive resin composition characterized by having an average value of R _top 5 or less.
(test)
Wiring composed of a cured product of the conductive resin composition having a length of 30 mm, a width of 500 μm, and a height of 50 μm on a substrate made of silicone rubber having a length of 5 cm, a width of 2 cm, and a height of 500 μm and a hardness of 30. The pattern is formed so that the center point of the surface composed of the length direction and the width direction side of the substrate and the center point of the surface composed of the length direction and the width direction side of the wiring pattern overlap. Use as a test piece.
This test piece is stretched by 20% in the length direction in 3 seconds while measuring resistance, held for 10 seconds, released from the stretch in 3 seconds, and held for 10 seconds. The conductive resin composition according to claim 1.
When the test was performed 100 times,
A conductive resin composition, wherein the resistance value R _re50 at the end of the 50th extension / release is 5 times or less the resistance value R _re5 at the end of the fifth extension / release. The conductive resin composition according to claim 1 or 2.
When the test was performed 100 times,
The resistance value _{R ex100} during the 100 th extension ends, characterized in that the following four times the resistance value _{R Re100} at the 100th elongation release completion, the conductive resin composition. The conductive resin composition according to any one of claims 1 to 3.
The elastomer (A) is a conductive resin composition containing silicone rubber. The conductive resin composition according to any one of claims 1 to 4.
The elastomer (A) is a first vinyl group-containing linear organopolysiloxane (A-1 (a)) and a vinyl group-containing linear organopolysiloxane (A-) having a vinyl group content of the first vinyl group. A conductive resin composition comprising a second vinyl group-containing linear organopolysiloxane (A-1 (b)) higher than 1 (a)). The conductive resin composition according to any one of claims 1 to 5 .
The (A) elastomer is a conductive resin composition containing (A-1) a linear group-containing linear organopolysiloxane and (A-2) an organohydrogenpolysiloxane. The conductive resin composition according to any one of claims 1 to 6 .
The metal powder (B) is a conductive resin composition containing silver powder or copper powder. The conductive resin composition according to any one of claims 1 to 7 .
A conductive resin composition containing 60% by mass or more and 88% by mass or less of the metal powder (B) with respect to the total solid content of the conductive resin composition. The conductive resin composition according to any one of claims 1 to 8.
The specific surface area of the silica particles (C) is 300 m. ² A conductive resin composition of / g. The conductive resin composition according to any one of claims 1 to 9.
A conductive resin composition comprising one or more selected from the group consisting of aliphatic hydrocarbons, aromatic hydrocarbons, ethers, haloalkanes, carboxylic acid amides, and sulfoxides. The conductive resin composition according to any one of claims 1 to 10 .
Only contains further (D) a silane coupling agent,
A conductive resin composition in which the (D) silane coupling agent contains a silane coupling agent having a vinyl group . The conductive resin composition according to any one of claims 1 to 11 .
A conductive resin composition further containing (E) platinum or a platinum compound other than the (B) metal powder. The conductive resin composition according to any one of claims 1 to 12.
A conductive resin composition used for forming elastic wiring. A wiring composed of a cured product of the conductive resin composition according to any one of claims 1 to 13 . A wiring board comprising the wiring according to claim 14 and a board. An electronic device comprising the wiring board according to claim 15 .

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