JP6977292B2 - Insulating paste - Google Patents

Description

The present invention relates to insulation paste.

In recent years, various developments have been made on materials used for substrates constituting elastic wiring boards. As a technique of this kind, for example, the technique described in Patent Document 1 is known. In the same document, a stretchable flexible circuit including an insulating base material made of a thermoplastic elastomer, a wiring layer formed on the insulating base material, and an insulating layer made of a thermoplastic elastomer formed on the wiring layer. The substrate is described. Further, it is described that a thermoplastic urethane sheet is used as the thermoplastic elastomer (Example of Patent Document 1, paragraph 0027).

Japanese Unexamined Patent Publication No. 2013-187380

However, as a result of the examination by the present inventor, in the elastomer substrate made of the elastomer described in the above document, the shape retention of the wiring pattern when the wiring made of the conductive paste is formed on the surface of the elastomer substrate is considered. It turned out that there was room for improvement.

As a result of further studies, the present inventor has found that when a conductive layer is formed on the surface of a dried insulating sheet using a conductive paste containing a solvent, the pattern shape of the conductive layer is well maintained. Found to be done.
Although the detailed mechanism is not clear, the solvent in the conductive layer soaks into the insulating sheet of the lower layer in contact with the lower surface of the conductive layer, so that the solvent is sufficiently dried even on the lower surface side of the conductive layer, and the conductivity is increased. It is considered that the pattern shape of the layer is good.
As a result of further diligent research based on such findings, we found an evaluation index that can appropriately evaluate the degree of solvent swelling after drying of the insulating sheet, and based on the evaluation index, the degree of solvent swelling after drying of the insulating sheet. As described above, it has been found that the shape retention of the conductive layer pattern is improved by setting the value to a predetermined value or more, and the present invention has been completed.

According to the present invention
An insulating paste used to form an insulating sheet containing an elastomer.
Contains elastomeric compositions and solvents
Provided is an insulating paste in which W2 / W1 × 100, which indicates the degree of solvent swelling after drying in the insulating sheet , which is measured under the following conditions, is 110% or more and 200% or less.
(Measurement condition)
The insulating paste is dried or cured to obtain an insulating sheet.
Obtained when the insulating sheet is dried for 60 minutes at 100 ° C., the weight of the insulating sheet and W1, thereafter, after said insulating sheet was immersed for 60 minutes in the measuring solvent at room temperature 25 ° C. , the weight of the insulating sheet and W2.
Using the obtained W1 and W2, the degree of solvent swelling after drying in the insulating sheet is determined based on the formula: W2 / W1 × 100.

Further, according to the present invention, there is provided an insulating paste which is an insulating paste used for forming the insulating sheet and contains an elastomer composition and a solvent.

According to the present invention, it is possible to provide an insulating sheet capable of realizing an insulating layer having excellent shape retention of a conductive layer pattern formed on a surface and an insulating paste for forming the insulating layer.

It is sectional drawing which shows the outline of the electronic device in this embodiment. It is sectional drawing which shows the outline of the manufacturing process of the electronic device in this embodiment.

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.

The outline of the insulating paste of this embodiment will be described.
The insulating sheet of the present embodiment contains an elastomer, and is configured such that W2 / W1 × 100, which indicates the degree of solvent swelling after drying, measured under the following conditions is 110% or more and 200% or less. can do.
(Measurement condition)
When the insulating sheet is dried at 100 ° C. for 60 minutes, the weight of the insulating sheet is W1, and then the insulating sheet is immersed in a measuring solvent at room temperature of 25 ° C. for 60 minutes. The weight of the insulating sheet is W2.

The insulating sheet of the present embodiment can be a dry film formed by drying a paste-like insulating resin composition (insulating paste) containing a solvent. This insulating paste is excellent in coating property and film forming property on the surface of the support. Further, since it has an elastomer composition, the cured product of the insulating paste can exhibit appropriate elasticity. Such an insulating paste or an insulating sheet can be suitable for, for example, an application for forming a substrate constituting an elastic wiring board.

Here, the elastic wiring board can be obtained by the following steps. First, the insulating paste of the present embodiment is applied onto the support substrate and dried to form a dry film (insulating layer). Subsequently, a coating film made of a conductive paste containing a solvent is formed on the obtained dry film by a printing method such as squeegee printing, and then the coating film is dried to obtain a patterned conductive layer. .. If necessary, these insulating layers and conductive layers may be cured by further heating. As described above, it is possible to obtain an elastic wiring board having a conductive layer having a pattern shape arranged on the insulating layer.

The present inventor examined an insulating paste in the manufacturing process of such an elastic wiring board, and applied a conductive paste containing a solvent to the surface of a dry film (insulating sheet) of the insulating paste. It has been found that when the conductive layer formed by drying is formed, the pattern shape of the conductive layer is well maintained.
Although the detailed mechanism is not clear, the solvent remaining in the conductive layer soaks into the dry film of the lower layer in contact with the lower surface of the conductive layer during drying, so that the solvent is sufficiently removed even on the lower surface side of the conductive layer. Therefore, it is considered that the pattern shape of the conductive layer becomes good.
As a result of further diligent research based on such findings, we found an evaluation index W2 / W1 that can appropriately evaluate the degree of solvent swelling after drying of the insulating sheet, and based on the evaluation index, after drying the insulating sheet. It has been found that the shape retention of the conductive layer pattern is improved by setting W2 / W1 indicating the degree of solvent swelling to a predetermined value or more, and the present invention has been completed.

Further, in the present embodiment, the W2 / W1 × 100 indicates how much solvent the dried insulating paste or insulating sheet absorbs again by appropriately selecting the drying conditions and the measuring solvent. It is an index that can be evaluated stably. By setting such an index W2 / W1 × 100 to the above lower limit value or more, the degree of solvent swelling is appropriately increased, so that the insulating sheet and the insulating paste used for forming the insulating sheet have a conductive layer pattern. Shape retention can be improved.

Further, by using the elastic wiring board using the insulating paste of the present embodiment as the substrate, it is possible to realize wiring having a good pattern shape and to realize a connection structure having good connection reliability.
Hereinafter, the insulating paste of this embodiment will be described.

The insulating paste of the present embodiment is an insulating paste used for forming an insulating sheet, and may contain an elastomer composition and a solvent. Since the insulating paste of the present embodiment contains an elastomer composition, even when an elastomer made of an insulating paste is used for an elastic substrate or the like, appropriate elasticity can be exhibited with respect to the elastomer. Further, the elastomer composition can be selected from those soluble in a solvent. Therefore, the insulating sheet made of the insulating paste of the present embodiment can absorb the solvent in the conductive paste, and can improve the shape stability of the wiring composed of the conductive paste.

(Elastomer)
As the elastomer, silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber and the like can be used. Among these, the elastomer can include one or more thermosetting elastomers selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. Further, the elastomer can contain silicone rubber from the viewpoint of being chemically stable and having excellent mechanical strength.
The thermosetting elastomer can be composed of a cured product of the thermosetting elastomer composition. For example, the silicone rubber can be composed of a cured product of a silicone rubber-based curable composition. The thermoplastic elastomer can be composed of a dried product of the thermoplastic elastomer. In the present specification, the elastomer of the insulating paste means an elastomer formed by drying or curing the insulating paste.

The elastomer composition is used for forming the above-mentioned elastomer, and is, for example, thermosetting used for forming one or more thermosetting elastomers selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. It can contain an elastomer composition, preferably a silicone rubber-based curable composition.

Hereinafter, a case where a silicone rubber-based curable composition is used as the silicone rubber as an example of the elastomer of the present embodiment will be described.

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

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

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

The content of the vinyl group of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably, for example, having two or more vinyl groups in the molecule and 15 mol% or less. , 0.01-12 mol%, more preferably. As a result, the amount of vinyl groups in the vinyl group-containing linear organopolysiloxane (A1) is optimized, and a network with each component described later can be reliably formed. In the present embodiment, "~" means to include the numerical values at both ends thereof.

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

The degree of polymerization of the vinyl group-containing linear organopolysiloxane (A1) is not particularly limited, but is preferably in the range of, for example, preferably about 1000 to 10000, and more preferably about 2000 to 5000. The degree of polymerization can be determined, for example, as the polystyrene-equivalent number average degree of polymerization (or number average molecular weight) in GPC (gel permeation chromatography) using chloroform as a developing solvent.

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

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

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

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

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

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

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

In the 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 (A1) represented by the formula (1), m is an integer of 0 to 2000, and n is 1000 to 10000. Is an integer of. m is preferably 0 to 1000, and n is preferably 2000 to 5000.

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

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

Further, the vinyl group-containing linear organopolysiloxane (A1) contains a first vinyl group having a vinyl group content of 2 or more in the molecule and 0.4 mol% or less. It contains a linear organopolysiloxane (A1-1) and a second vinyl group-containing linear organopolysiloxane (A1-2) having a vinyl group content of 0.5 to 15 mol%. It is preferable to have it. As raw rubber which is a raw material of silicone rubber, a first vinyl group-containing linear organopolysiloxane (A1-1) having a general vinyl group content and a second vinyl group-containing direct compound having a high vinyl group content. By combining with a chain organopolysiloxane (A1-2), the vinyl group can be unevenly distributed, and the cross-linking density can be more effectively formed in the cross-linking network of the silicone rubber. As a result, the tear strength of the silicone rubber can be increased more effectively.

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

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

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

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

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

<< Organohydrogen Polysiloxane (B) >>
The silicone rubber-based curable composition of the present embodiment can contain organohydrogenpolysiloxane (B).
The organohydrogenpolysiloxane (B) can include a linear organohydrogenpolysiloxane (B1) having a linear structure.

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

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

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

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

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

In the formula (2), R ⁴ 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, 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 (B1) represented by the formula (2), where m is an integer of 2 to 150 and n is an integer of 2 to 150. Is. Preferably, m is an integer of 2 to 100 and n is an integer of 2 to 100.

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

The organohydrogenpolysiloxane (B) may contain a branched organohydrogenpolysiloxane (B2) having a branched structure.

In the present embodiment, the content of the elastomer composition in the insulating paste is preferably 5% by mass or more, more preferably 8% by mass or more, and 10% by mass with respect to the entire insulating paste. The above is more preferable. The content of the elastomer composition in the insulating paste is preferably 50% by mass or less, more preferably 45% by mass or less, and 40% by mass or less with respect to the entire insulating paste. Is even more preferable.
By setting the content of the elastomer composition to the above lower limit value or more, the elastomer of the insulating paste can have appropriate flexibility. Further, by setting the content of the elastomer composition to the above upper limit value or less, the mechanical strength of the elastomer can be improved.

<< Silica particles (C) >>
The insulating paste of the present embodiment may contain silica particles (C), if necessary. This makes it possible to improve the hardness and mechanical strength of the elastomer formed from the insulating paste. In addition, the insulating property of the elastomer of the insulating paste can be enhanced.

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

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

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

In the present embodiment, the content of the silica particles (C) in the insulating paste is preferably 1% by mass or more, more preferably 3% by mass or more, 5 by mass, based on the entire insulating paste. It is more preferably mass% or more. The content of the silica particles (C) in the insulating paste is preferably 50% by mass or less, more preferably 45% by mass or less, and 40% by mass or less with respect to the entire insulating paste. Is more preferable.
By setting the content of the silica particles (C) to the above lower limit value or more, the elastomer of the insulating paste can have an appropriate mechanical strength. On the other hand, by setting the content of the silica particles (C) to the above upper limit value or less, the elastomer can have an appropriate expansion / contraction property. This makes it possible to increase the durability during repeated use.

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

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

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

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

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

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

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

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

Further, examples of the hydrolyzable group include an alkoxy group such as a methoxy group and an ethoxy group, a chloro group or a silazane group, and among them, a silazane group is preferable because it has high reactivity with the silica particles (C). Incidentally, those having a silazane group as hydrolyzable groups, the characteristics of its structure the formula (4) in the structure of (Y _n -Si-) comes to have two.

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

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

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

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

In the present embodiment, the content of platinum or the platinum compound (E) in the insulating paste is preferably 0.0001% by mass or more, preferably 0.0002% by mass or more, based on the entire insulating paste. More preferably, it is more preferably 0.0003% by mass or more. The content of platinum or the platinum compound (E) in the insulating paste is preferably 1% by mass or less, more preferably 0.5% by mass or less, based on the entire insulating paste. It is more preferably 0.1% by mass or less.
By setting the content of platinum or the platinum compound (E) to the above lower limit value or more, the insulating paste can be cured at an appropriate rate. Further, by setting the content of platinum or the platinum compound (E) to the above upper limit value or less, it is possible to contribute to the reduction of the cost when producing the insulating paste.

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

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

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

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

(solvent)
The insulating paste of this embodiment contains a solvent. As the solvent, various known solvents can be used, and for example, a high boiling point solvent can be included. These may be used alone or in combination of two or more.

The lower limit of the boiling point of the high boiling point solvent is, for example, 100 ° C. or higher, preferably 130 ° C. or higher, and more preferably 150 ° C. or higher. As a result, when the insulating paste is applied onto the support substrate, the film-forming property of the obtained coating film can be improved and the film thickness variation of the coating film can be suppressed. On the other hand, the upper limit of the boiling point of the high boiling point solvent is not particularly limited, but may be, for example, 300 ° C. or lower, 290 ° C. or lower, or 280 ° C. or lower. As a result, excessive heat history at the time of wiring formation can be suppressed, so that damage to electronic components and wiring can be suppressed. Further, since the solvent in the elastomer of the insulating paste can be sufficiently volatilized as the substrate, the shape of the wiring formed by printing using the conductive paste on the surface of the substrate can be well maintained. ..

The solvent of the present embodiment can be appropriately selected from the viewpoint of the solubility of the elastomer and the boiling point. For example, an aliphatic hydrocarbon having 5 or more and 20 or less carbon atoms, preferably an aliphatic hydrocarbon having 8 or more and 18 or less carbon atoms. Hydrocarbons, more preferably aliphatic hydrocarbons having 10 or more and 15 or less carbon atoms can be contained.

Further, examples of the solvent of the present embodiment include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, methylcyclohexane, ethylcyclohexane, octane, decane, dodecane and tetradecane; benzene, toluene, ethylbenzene and xylene. , Trifluoromethylbenzene, aromatic hydrocarbons such as benzotrifluoride; diethyl ether, diisopropyl ether, dibutyl ether, cyclopentylmethyl ether, cyclopentyl ethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, 1,4- Ethers such as dioxane, 1,3-dioxane, tetrahydrofuran; haloalkanes such as dichloromethane, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane; Carboxyric acid amides such as N, N-dimethylformamide and N, N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide can be exemplified. These may be used alone or in combination of two or more.
The solvent used here may be appropriately selected from the solvents capable of uniformly dissolving or dispersing the composition components in the above-mentioned insulating paste.

_{The upper limit of the polarity term (δ p} ) of the Hansen solubility parameter of the solvent is, for example, 10 MPa ^1/2 or less, preferably 7 MPa ^1/2 or less, and more preferably 5.5 MPa ^1/2 or less. It can contain a first solvent. Thereby, in the insulating paste, the dispersibility and solubility of the elastomer composition such as the silicone rubber-based curable resin composition can be improved. The lower limit of the polarity term (δ _p ) of the first solvent is not particularly limited, but may be, for example, 0 Pa ^{1/2 or more.}

_{The upper limit of the hydrogen bond term (δ h} ) of the Hansen solubility parameter in the first solvent is, for example, 20 MPa ^1/2 or less, preferably 10 MPa ^1/2 or less, and more preferably 7 MPa ^1/2 or less. be. Thereby, in the insulating paste, the dispersibility and solubility of the elastomer composition such as the silicone rubber-based curable resin composition can be improved. The lower limit of the hydrogen bond term (δ _h ) of the first solvent is not particularly limited, but may be, for example, 0 Pa ^{1/2 or more.}

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

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

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

Hereinafter, the characteristics of the insulating sheet and the insulating paste of this embodiment will be described.

In the insulating sheet of the present embodiment, the lower limit of W2 / W1 × 100, which indicates the degree of solvent swelling after drying, measured under the following conditions is, for example, 110% or more, preferably 120% or more. , More preferably 130% or more. An insulating sheet made of a cured product of such an insulating paste can realize an insulating layer having an excellent shape retention of a conductive layer pattern formed on the surface. On the other hand, the upper limit of W2 / W1 × 100 indicating the degree of solvent swelling is not particularly limited, but may be, for example, 200% or less, preferably 190% or less, and more preferably 180% or less. As a result, for example, the mask used when applying the conductive paste on the insulating sheet leaves mesh (mesh structure) marks on the surface of the insulating sheet, and the mesh marks cause variations in the film thickness of the conductive layer. It can be suppressed from occurring.

The following measurement conditions can be used in the measurement of the degree of solvent swelling.
When the insulating sheet is dried at 100 ° C. for 60 minutes, the weight of the insulating sheet is W1, and then the insulating sheet is immersed in a measuring solvent at room temperature of 25 ° C. for 60 minutes. The weight of the sex sheet is W2. The ratio (%) of W2 to W1 can be defined as the degree of solvent swelling.

As the above-mentioned solvent for measurement, the above-mentioned solvent can be used, but for example, the same kind of solvent as the conductive paste may be used, and various high boiling point solvents can be used. Specifically, as the measurement solvent, a first solvent having a small polar term or hydrogen bond term may be used, or for example, tetradecane or the like may be used.

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

In the insulating paste of the present embodiment, the viscosity measured at a shear rate of 1 [1 / s] at room temperature of 25 ° C. is η1, and the viscosity measured at a shear rate of 5 [1 / s] is η5. The viscosity index is defined as the viscosity ratio (η1 / η5). At this time, the lower limit of the thixotropic index is, for example, 1.0 or more, preferably 1.1 or more, and more preferably 1.2 or more. This facilitates printing work with a squeegee of insulating paste. On the other hand, the upper limit of the thixotropic index is, for example, 3.0 or less, preferably 2.5 or less, and more preferably 2.0 or less. This makes it possible to improve the leveling property of the insulating paste.

The upper limit of the durometer hardness A specified in accordance with JIS K6253 (1997) of the insulating sheet of the present embodiment may be, for example, 80 or less, preferably 70 or less, and more preferably 65 or less. But it may be. As a result, the flexibility of the insulating sheet made of a cured product of the insulating paste can be improved, and deformation such as bending and stretching can be facilitated. The lower limit of the durometer hardness A of the insulating sheet is, for example, 10 or more, preferably 20 or more, and more preferably 30 or more. By using such a cured product as the base substrate, the wiring formability on the surface of the base substrate can be improved. For example, it is possible to suppress variations in the shape and height of wiring formed by printing such as screen printing.

The lower limit of the tensile strength of the insulating sheet of the present embodiment measured in accordance with JIS K6251 (2004) is, for example, 4.0 MPa or more, preferably 5.0 MPa or more, and more preferably. It is 6.0 MPa or more, more preferably 7.0 MPa or more. This makes it possible to improve the mechanical strength of the insulating sheet made of a cured product of the insulating paste. In addition, the breaking energy can be increased. Therefore, it is possible to realize a cured product having excellent durability that can withstand repeated deformation. On the other hand, the upper limit of the tensile strength of the cured product of the insulating sheet is not particularly limited, but may be, for example, 15 MPa or less, or 13 MPa or less. This makes it possible to balance the elasticity and mechanical strength of the cured product of the insulating sheet.

The lower limit of the tear strength of the insulating sheet of the present embodiment measured in accordance with JIS K6252 (2001) may be, for example, 15 N / mm or more, 20 N / mm or more, preferably 25 N / mm. The above is more preferably 30 N / mm or more, further preferably 33 N / mm or more, and even more preferably 35 N / mm or more. This makes it possible to improve the durability and mechanical strength of the insulating sheet made of a cured product of the insulating paste during repeated use. On the other hand, the upper limit of the tear strength of the cured product of the insulating sheet is not particularly limited, but may be, for example, 70 N / mm or less, or 60 N / mm or less. Thereby, various characteristics of the cured product of the insulating sheet of the present embodiment can be balanced.

In the present embodiment, for example, by appropriately selecting the type and blending amount of each component contained in the insulating paste, the method for preparing the insulating paste, etc., the above W2 / W1 × 100, viscosity, thixotropic index, hardness, etc. It is possible to control the tensile strength and tear strength. Among these, for example, the type of solvent such as a hydrophobic solvent, a hydrocarbon solvent, a solvent having a high boiling point suitable for printing, or a solvent having a small polar term or a hydrogen bond term should be appropriately selected, and silica particles (C). ), The mixing ratio, and the use of a vinyl group-containing organopolysiloxane (A) having a vinyl group at the end to control the crosslink density of the resin and the uneven distribution of the crosslinked structure, and the silane cup of the silica particles (C). The reaction between the silane coupling agent (D) and the silica particles (C), such as surface modification with the ring agent (D) and addition of water, can proceed more reliably, and the curing temperature and curing time are appropriate. The above-mentioned W2 / W1 × 100, viscosity, thixoindex, hardness, tensile strength and tear strength can be mentioned as factors for setting the desired numerical range.

(Manufacturing method of insulating paste)
Hereinafter, a method for producing an insulating paste according to this embodiment will be described.

The insulating paste of the present embodiment can be produced, for example, by going through the following steps.

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

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

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

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

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

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

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

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

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

[2] Next, the organohydrogenpolysiloxane (B) and platinum or the platinum compound (E) are weighed in a predetermined amount, and then the kneaded product prepared in the above step [1] using an arbitrary kneading device. , Each component (B) and (E) is kneaded to obtain a silicone rubber-based curable composition (elastomer composition).

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

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

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

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

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

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

[3] Next, the insulating paste of the present embodiment can be obtained by dissolving the elastomer composition (silicone rubber-based curable composition) obtained in the step [2] in a solvent.

[Use]
Hereinafter, an example of the use of the insulating paste of the present embodiment will be described with reference to FIG. FIG. 1 shows an outline of an electronic device 100 provided with wiring as a cross-sectional view.

As shown in FIG. 1, the electronic device 100 can include a wiring board 50 and an electronic component 60. The wiring board 50 is configured by providing the wiring 10 on the board 20. As the substrate 20, an insulating substrate having elasticity can be used. The substrate 20 can be made of a cured product obtained by curing the insulating paste of the present embodiment. The electronic component 60 may be configured to be electrically connected to the wiring 10 constituting such an elastic wiring board (wiring board 50).

Since the insulating paste of the present embodiment can maintain mechanical strength and durability when repeatedly expanded and contracted with respect to the obtained cured product, it is possible to realize the structure of the electronic device 100 having excellent connection reliability. Can be done.
The electronic device 100 of the present embodiment is used, for example, as a wearable device, and can be suitably used for a device that is repeatedly expanded and contracted in each direction.

Further, the wiring 10 constituting the electronic device 100 of the present embodiment is usually made of a flexible conductive material. The conductive material can include, for example, an elastomer composition and a conductive filler.
As the elastomer composition, the same elastomer composition as that exemplified as the material of the above-mentioned insulating paste can be adopted. Specifically, an elastomer composition used for forming silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, ethylene propylene rubber and the like can be used, depending on the application and the like. , This material can be selected as appropriate.

The wiring 10 may be composed of a cured product of the conductive paste obtained by curing the conductive paste containing the silicone rubber-based curable composition and the conductive filler.

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

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

Further, in is not the particle size also limits the metal powder (G), for example, preferably has an average particle at diameter _{D 50} at 0.001μm, more preferably at 0.01μm or more, more preferably 0.1μm or more be. The particle size of the metal powder (G) is, 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 paste. The particle size of the metal powder (G) is defined as an average value of 200 arbitrarily selected metal powders, for example, by observing a conductive paste or a cured product thereof with a transmission electron microscope or the like and performing image analysis. can do.

The content of the conductive filler in the conductive paste is preferably 30% by mass or more, more preferably 40% by mass or more, and more preferably 50% by mass or more with respect to the entire conductive paste. Is even more preferable. The content of the conductive filler in the conductive paste is preferably 85% by mass or less, more preferably 75% by mass or less, and 65% by mass or less with respect to the entire conductive pace. Is even more preferable.
By setting the content of the metal powder (G) to the above lower limit value or more, the cured product of the insulating paste can have appropriate conductive properties. Further, by setting the content of the metal powder (G) to the above upper limit value or less, the cured product can have appropriate flexibility.

The lower limit of the content of the silica particles (C) in the conductive paste is, for example, 1% by mass or more, preferably 1% by mass or more, based on 100% by mass of the total amount of the silica particles (C) and the conductive filler. Is 3% by mass or more, and more preferably 5% by mass or more. This makes it possible to improve the mechanical strength of the cured product of the conductive paste. On the other hand, the upper limit of the content of the silica particles (C) in the conductive paste is, for example, 20% by mass or less with respect to 100% by mass of the total amount of the silica particles (C) and the conductive filler. It is preferably 15% by mass or less, and more preferably 10% by mass or less. This makes it possible to balance the expansion and contraction electrical characteristics and the mechanical strength of the cured product of the conductive paste.

In the present embodiment, the above-mentioned solvent type can be used as the solvent for the conductive paste, and among these, the solvent exhibiting solubility in the insulating paste or the insulating sheet which is a cured product of the insulating paste. Can be used. As a specific solvent for the conductive paste, for example, a high boiling point solvent or a solvent having a polar term (δ _p ) or a hydrogen bond term (δ _h ) of HSP of not more than the above upper limit can be used.

The insulating paste of the present embodiment can be used for a substrate constituting an elastic substrate having elastic wiring formed of a cured product of the conductive paste as described above, and for an interlayer insulating layer between these wirings.

Further, the electronic component 60 may be appropriately selected from known components according to the intended use. Specific examples thereof include semiconductor devices, resistors and capacitors other than semiconductor devices, and the like. Examples of the semiconductor element include a transistor, a diode, an LED, a capacitor and the like. In the electronic device 100 of the present embodiment, the electronic component 60 is electrically connected by the 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. The cover material 30 may be configured to cover the electronic component 60 and the wiring 10 on the substrate 20.
Further, the cover material 30 can be made of the same material as the substrate 20. 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, and can contribute to extending the life of the electronic device 100.

Next, an example of the manufacturing process of the electronic device 100 of the present embodiment will be described with reference to FIG.
FIG. 2 is a cross-sectional view showing an outline of the manufacturing process of the electronic device 100 in the present embodiment.

First, as shown in FIG. 2A, the support 120 is installed on the workbench 110, and the insulating paste 130 is applied onto the support 120. As the coating method, various methods can be used, and for example, a printing method such as a squeegee method using a squeegee 140 can be used. Subsequently, the coating film-like insulating paste 130 can be dried to form an insulating layer 132 (dried insulating sheet) on the support 120. The drying conditions can be appropriately set according to the type and amount of the solvent in the insulating paste 130, and for example, the drying temperature may be 150 ° C. to 180 ° C., the drying time may be 1 minute to 30 minutes, or the like. ..

Subsequently, as shown in FIG. 2B, a mask 160 having a predetermined opening pattern shape is arranged on the insulating layer 132. Then, as shown in FIGS. 2 (b) and 2 (c), the conductive paste 150 is applied onto the insulating layer 132 via the mask 160. As the coating method, the same method as the coating method of the insulating paste 130 can be used, and for example, squeegee printing with the squeegee 140 may be used. Here, when the insulating paste 130 and the conductive paste 150 each contain a thermosetting elastomer composition, after laminating a conductive coating film (conductive layer 152) having a predetermined pattern shape on the dried insulating layer 132, These may be cured collectively. The curing treatment can be appropriately set depending on the thermosetting elastomer composition, and for example, the curing temperature can be 160 ° C. to 220 ° C., the curing time can be 1 hour to 3 hours, or the like. As shown in FIG. 2D, the mask 160 can be removed after the curing treatment or before the curing treatment. As a result, it is possible to form wiring which is a cured product of the conductive layer 152 and has a predetermined pattern shape on the substrate composed of the cured product of the insulating layer 132.

Subsequently, as shown in FIG. 2 (e), the insulating paste 170 is further coated on the insulating layer 132 and the patterned conductive layer 152 to form the insulating layer 172 as shown in FIG. 2 (f). can do. These steps may be repeated as appropriate. It is also possible to separate the support 120 from the insulating layer 132.
As a result, the electronic device 100 shown in FIG. 2 (f) can be obtained.

When an insulating sheet is used instead of the insulating paste, the process may be started from the step shown in FIG. 2 (b). That is, the insulating sheet may be placed on the support 120, dried for a predetermined period, and then the conductive paste 150 may be applied onto the insulating sheet via the mask 160. Subsequent steps can be performed according to the above steps. This makes it possible to obtain the electronic device 100 shown in FIG. 2 (f).

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like to the extent that the object of the present invention can be achieved are included in the present invention.
Hereinafter, an example of the reference form will be added.
1. 1. An insulating sheet containing an elastomer,
An insulating sheet in which W2 / W1 × 100, which indicates the degree of solvent swelling after drying, measured under the following conditions is 110% or more and 200% or less.
(Measurement condition)
When the insulating sheet is dried at 100 ° C. for 60 minutes, the weight of the insulating sheet is W1, and then the insulating sheet is immersed in a measuring solvent at room temperature of 25 ° C. for 60 minutes. The weight of the insulating sheet is W2.
2. 2. 1. 1. The insulating sheet described in
An insulating sheet used to form a substrate that constitutes an elastic wiring board.
3. 3. 1. 1. Or 2. The insulating sheet described in
An insulating sheet having a durometer hardness A of 10 or more and 80 or less specified in accordance with JIS K6253 (1997).
4. 1. 1. From 3. The insulating sheet according to any one of the above.
An insulating sheet having a tensile strength measured according to IS K6251 (2004) of 4.0 MPa or more and 15 MPa or less.
5. 1. 1. From 4. The insulating sheet according to any one of the above.
An insulating sheet having a tear strength measured according to JIS K6252 (2001) of 15 N / mm or more.
6. 1. 1. From 5. An insulating paste used for forming the insulating sheet according to any one of the above.
An insulating paste containing an elastomer composition and a solvent.
7. 6. The insulating paste described in
An insulating paste containing a high boiling point solvent having a boiling point of 100 ° C. or higher and 300 ° C. or lower.
8. 6. Or 7. The insulating paste described in
An insulating paste in which the solvent contains an aliphatic hydrocarbon having 5 or more and 20 or less carbon atoms.
9. 6. From 8. The insulating paste according to any one of the above.
An insulating paste containing a first solvent in which the polarity term (δ _p ) of the Hansen solubility parameter is 10 MPa ^{1/2 or less.}
10. 6. From 9. The insulating paste according to any one of the above.
An insulating paste having a viscosity of 1 Pa · s or more and 100 Pa · s or less at room temperature of 25 ° C.
11. 6. From 10. The insulating paste according to any one of the above.
The viscosity ratio of the insulating paste at room temperature of 25 ° C. when the viscosity measured at a shear rate of 1 [1 / s] is η1 and the viscosity measured at a shear rate of 5 [1 / s] is η5. An insulating paste having a viscosity index of (η1 / η5) of 1.0 or more and 3.0 or less.
12. 6. From 11. The insulating paste according to any one of the above.
An insulating paste comprising the thermoplastic elastomer composition for forming one or more elastomers selected from the group consisting of silicone rubber, urethane rubber, and fluororubber.
13. 6. From 12. The insulating paste according to any one of the above.
An insulating paste in which the elastomer composition contains a silicone rubber-based curable composition.
14. 6. From 13. The insulating paste according to any one of the above.
An insulating paste having a content of the elastomer composition of 5% by mass or more and 50% by mass or less with respect to the entire insulating paste.
15. 6. From 14. The insulating paste according to any one of the above.
An insulating paste further comprising silica particles (C).
16. 15. The insulating paste described in
An insulating paste in which the content of the silica particles (C) is 1% by mass or more and 50% by mass or less with respect to the entire insulating paste.

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.
(Vinyl group-containing organopolysiloxane (A))
(A1-1): First vinyl group-containing linear organopolysiloxane: Vinyl group content is 0.13 mol%, Mn = 227,734, Mw = 573,903, IV value (dl / g) = 0.89), Vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 1 (structure represented by the above formula (1-1)).
(A1-2): Second vinyl group-containing linear organopolysiloxane: Vinyl group content is 0.92 mol%, vinyl group-containing dimethylpolysiloxane synthesized by the following synthesis scheme 2 (the above formula (1-). Structure represented by 1) in which R ¹ and R ² are vinyl groups)

(Organohydrogenpolysiloxane (B))
(B1): Linear organohydrogenpolysiloxane: "88466" manufactured by Momentive Co., Ltd.

(Silica particles (C))
(C1): Silica fine particles (particle size 7 nm, specific surface area 300 m ² / g), manufactured by Nippon Aerosil Co., Ltd., "AEROSIL 300"

(Silane Coupling Agent (D))
(D1): Hexamethyldisilazane (HMDZ), manufactured by Gelest, "HEXAMETHYLDISILAZANE (SIH6110.1)".
(D2): Divinyltetramethyldisilazane, manufactured by Gelest, "1,3-DIVINYLTRAMETHYLDISILAZANE (SID4612.0)".

(Platinum or platinum compound (E))
(E1): Platinum compound, PLATINUM DIVINYLTETRAMETHYLDISILOXANE COMPLEX (in xylene) (manufactured by Gelest, trade name "SIP6831.2")

(Water (F))
(F1): Pure water

(Metal powder (G))
(G1): Silver powder, manufactured by DOWA Electronics, trade name "3-8F", average particle size D ₅₀ 1.6 μm

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

(Synthesis of vinyl group-containing organopolysiloxane (A))
[Synthesis scheme 1: Synthesis of first vinyl group-containing linear organopolysiloxane (A1-1)]
The first vinyl group-containing linear organopolysiloxane (A1-1) was synthesized according to the following formula (7).
That is, 74.7 g (252 mmol) of octamethylcyclotetrasiloxane and 0.1 g of potassium silicate were placed in a 300 mL separable flask having a cooling tube and a stirring blade substituted with Ar gas, heated, and heated at 120 ° C. for 30 minutes. Stirred. At this time, an increase in viscosity was confirmed.
Then, the temperature was raised to 155 ° C., and stirring was continued for 3 hours. Then, after 3 hours, 0.1 g (0.6 mmol) of 1,3-divinyltetramethyldisiloxane was added, and the mixture was further stirred at 155 ° C. for 4 hours.
After 4 hours, it was diluted with 250 mL of toluene and then washed 3 times with water. The organic layer after washing was washed with 1.5 L of methanol several times for reprecipitation purification, and the oligomer and the polymer were separated. The obtained polymer was dried under reduced pressure at 60 ° C. overnight to obtain a first vinyl group-containing linear organopolysiloxane (A1-1) (Mw = 573,903, Mn = 227,734). The vinyl group content calculated by 1 H-NMR spectrum measurement was 0.13 mol%.

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

[Preparation of insulating paste]
(Examples 1 to 6: Preparation of silicone rubber-based curable compositions 1 to 6)
In Examples 1 to 6, silicone rubber-based curable compositions 1 to 6 were prepared as follows. First, a mixture of 90% vinyl group-containing organopolysiloxane (A), silane coupling agent (D) and water (F) is kneaded in advance at the ratio shown in Table 1 below, and then silica particles (silica particles ()) are added to the mixture. C) was added and further kneaded to obtain a kneaded product (silicone rubber compound).
Here, the kneading after the addition of the silica particles (C) is carried out in the first step of kneading under a nitrogen atmosphere at 60 to 90 ° C. for 1 hour for the coupling reaction, and the removal of the by-product (ammonia). Therefore, it is carried out by going through the second step of kneading under a reduced pressure atmosphere under the condition of 160 to 180 ° C. for 2 hours, and then cooling, and the remaining 10% of the vinyl group-containing organopolysiloxane (A) is added twice. It was added separately and kneaded for 20 minutes.
Subsequently, the organohydrogenpolysiloxane (B), platinum or platinum compound (E) and the reaction inhibitor were added to 100 parts by weight of the obtained kneaded product (silicone rubber compound) at the ratio shown in Table 1 below. , Kneaded with a roll to obtain silicone rubber-based curable compositions 1 to 6 (elastomer composition).

Subsequently, 100 parts by weight of the obtained silicone rubber-based curable composition 1 to 6 was immersed in 212.5 parts by weight of tetradecane, and then stirred with a rotation / revolution mixer to obtain a liquid insulating paste 1 to 6. 6 was obtained.

[Preparation of conductive paste]
Subsequently, 100 parts by weight of the silicone rubber-based curable composition 5 shown in Table 1 was immersed in 233 parts by weight of tetradecane, and then stirred with a rotation / revolution mixer to prepare a solution of silver powder (silver powder). G1) 400 parts by weight was added and the mixture was stirred again with a rotation / revolution mixer to obtain a conductive paste.

(Making silicone rubber)
In Examples 1 to 6, the obtained silicone rubber-based curable compositions 1 to 6 were pressed at 160 ° C. and 10 MPa for 20 minutes to form a sheet having a thickness of 1 mm and primary cured. Subsequently, it was heated at 200 ° C. for 4 hours for secondary curing.
As a result, insulating sheets 1 to 6 made of sheet-shaped silicone rubber (cured product of silicone rubber-based curable compositions 1 to 6) were obtained. The following evaluation was performed on the obtained insulating sheet. The evaluation results are shown in Table 2.
The tensile strength was measured with three samples, and the average value of the three was used as the measured value. The tear strength was measured with 5 samples, and the average value of 5 was used as the measured value. Further, the hardness was measured at n = 5 in each sample using two samples, and the average value of 10 measurements was taken as the measured value. The average value for each is shown in Table 2.

(Example 7)
As the insulating sheet 7, a natural rubber sheet (hardness 60, thickness 1 mm, width 500 mm × length 500 mm, AS ONE product code 2-9289-02) purchased from AS ONE Corporation was used. The following evaluation was performed. The evaluation results were the same as the number of samples and the number of evaluations described in the preparation of silicone rubber.

(Example 8)
As the insulating sheet 8, an ethylene propylene rubber sheet (hardness 65, thickness 1 mm, width 500 mm × length 500 mm, AS ONE product code 2-9301-02) purchased from AS ONE Corporation was used.

(Comparative Example 1)
As the insulating sheet 9, a chloroprene rubber sheet (hardness 60, thickness 1 mm, width 500 mm × length 500 mm, AS ONE product code 2-9293-02) purchased from AS ONE Corporation was used.

(Comparative Example 2)
As the insulating paste 7, water-dispersed urethane (Dispacol U42 manufactured by Sumika Bayer Urethane Co., Ltd.) was poured into a mold and air-dried for 3 days to obtain an insulating sheet 10 having a thickness of 150 mm × 150 mm and a thickness of 1 mm.

(Comparative Example 3)
As the insulating sheet 11, a sheet of a polyether type urethane purchased from Fuso Rubber Sangyo Co., Ltd. (hardness 90, thickness 1 mm, width 1000 mm × length 2000 mm, rubber communication product code 10005-0002-0) was used.

(Comparative Example 4)
As the insulating sheet 12, a polyester type urethane sheet (hardness 30, thickness 1 mm, width 1000 mm × length 2000 mm, rubber communication product code 10199-0004-0) purchased from Fuso Rubber Sangyo Co., Ltd. was used.

(Comparative Example 5)
As the insulating sheet 13, a fluororubber sheet (thickness 1 mm, manufactured by Kureha Elastomer Co., Ltd., FB760N) was used.

(Comparative Example 6)
As the insulating sheet 14, a nitrile rubber sheet (hardness 60, thickness 1 mm, width 300 mm × length 300 mm, AS ONE product code 2-9305-01) purchased from AS ONE Corporation was used.

In the solubility parameter (HSP) of Hansen of the solvent in Table 2, the dispersion term (δ _d ) of tetradecane: 15.8 MPa ^1/2 , the polarity term (δ _p ): 0 MPa ^1/2 , the hydrogen bond term (δ _h ). : 0 MPa ^1/2 , water dispersion term (δ _d ): 17.9 MPa ^1/2 , polarity term (δ _p ): 12.8 MPa ^1/2 , hydrogen bond term (δ _h ): 24.3 MPa ¹ It was ^{/ 2.} The boiling point of tetradecane was 253 ° C.

[Evaluation of insulating paste and insulating sheet]
The obtained insulating paste and insulating sheet were evaluated according to the following items.

(Measurement of solvent swelling degree)
In each Example and each Comparative Example, the obtained insulating sheet was dried at 100 ° C. for 60 minutes, and the weight W1 of the insulating sheet at that time was measured. Then, the insulating sheet was immersed in a measuring solvent at room temperature of 25 ° C. for 60 minutes, and the weight W2 of the insulating sheet at that time was measured. Tetradecane was used as the measurement solvent. The degree of solvent swelling after drying in the insulating sheet was W2 / W1 × 100 (%). The results are shown in Table 1.

<Hardness: Durometer hardness A>
Six insulating sheets of each example and each comparative example having a thickness of 1 mm were laminated to prepare a test piece having a thickness of 6 mm. At room temperature of 25 ° C., the hardness (hardness) of the obtained test piece was measured with a type A durometer according to JIS K6253 (1997).

<Tensile strength>
Using the obtained insulating sheets having a thickness of 1 mm for each Example and each Comparative Example, a dumbbell-shaped No. 3 test piece was prepared in accordance with JIS K6251 (2004), and obtained at room temperature of 25 ° C. The tensile strength of the dumbbell-shaped No. 3 test piece was measured. The unit is MPa.

<Tear strength>
Using the obtained insulating sheets of 1 mm in thickness of each Example and Comparative Examples, a crescent-shaped test piece was prepared in accordance with JIS K6252 (2001) at room temperature of 25 ° C., and the obtained crescent was obtained. The tear strength of the shape test piece was measured. The unit is N / mm.

(Viscosity, thixotropic index)
With respect to the obtained insulating paste, a shear rate of 1 [1 / s], a shear rate of 5 [1 / s], and a shear rate of 20 [1 /] at room temperature of 25 ° C. were used using TPE-100H manufactured by Toki Sangyo Co., Ltd. The viscosity was measured in each of s]. For the thixotropy, the thixotropy is the viscosity ratio (η1 /) when the viscosity measured at a shear rate of 1 [1 / s] is η1 and the viscosity measured at a shear rate of 5 [1 / s] is η5. It was calculated as η5).

(Evaluation of shape retention of conductive layer pattern)
On the insulating sheet obtained in each Example / Comparative Example, a mask (SUS length 100 mm × width 100 mm × thickness 200 μm, L / S = 500 μm / 500 μm, length 20 mm (10 lines) is opened. The obtained conductive paste was cast and squeezed with a metal blade. Then, the mask was removed, dried and cured in an oven at 180 ° C. for 2 hours to form a conductive layer pattern (wiring) on the insulating sheet (substrate). After curing, the adjacent wiring was visually observed to confirm whether the wiring was independent, and the number of independent wiring was measured.
◎: All 10 pieces ○: 5 pieces or more, 9 pieces or less ×: 4 pieces or less

It was found that the insulating sheet obtained in each example was superior in shape retention of the conductive layer pattern formed on the surface as compared with the insulating sheet of each comparative example.

10 Wiring 20 Board 30 Cover material 50 Wiring board 60 Electronic components 100 Electronic device 110 Worktable 120 Support 130 Insulation paste 132 Insulation layer 140 Squeegee 150 Conductive paste 152 Conductive layer 160 Mask 170 Insulation paste 172 Insulation layer

Claims (16)

An insulating paste used to form an insulating sheet containing an elastomer.
Contains elastomeric compositions and solvents
An insulating paste in which W2 / W1 × 100, which indicates the degree of solvent swelling after drying in an insulating sheet , is 110% or more and 200% or less, which is measured under the following conditions.
(Measurement condition)
The insulating paste is dried or cured to obtain an insulating sheet.
Obtained when the insulating sheet is dried for 60 minutes at 100 ° C., the weight of the insulating sheet and W1, thereafter, after said insulating sheet was immersed for 60 minutes in the measuring solvent at room temperature 25 ° C. , the weight of the insulating sheet and W2.
Using the obtained W1 and W2, the degree of solvent swelling after drying in the insulating sheet is determined based on the formula: W2 / W1 × 100. The insulating paste according to claim 1.
An insulating paste used to form a substrate that constitutes an elastic wiring board. The insulating paste according to claim 1 or 2.
An insulating paste having a durometer hardness A of 10 or more and 80 or less specified in accordance with JIS K6253 (1997) of the insulating sheet. The insulating paste according to any one of claims 1 to 3.
An insulating paste having a tensile strength measured according to JIS K6251 (2004) of the insulating sheet of 4.0 MPa or more and 15 MPa or less. The insulating paste according to any one of claims 1 to 4.
An insulating paste having a tear strength measured according to JIS K6252 (2001) of the insulating sheet of 15 N / mm or more. The insulating paste according to any one of claims 1 to 5.
An insulating paste containing a high boiling point solvent having a boiling point of 100 ° C. or higher and 300 ° C. or lower. The insulating paste according to any one of claims 1 to 6.
An insulating paste in which the solvent contains an aliphatic hydrocarbon having 5 or more and 20 or less carbon atoms. An insulating paste according to any one of claims 1 or et 7,
An insulating paste containing a first solvent in which the polarity term (δ _p ) of the Hansen solubility parameter is 10 MPa ^{1/2 or less.} The insulating paste according to any one of claims 1 to 8.
An insulating paste having a viscosity of 1 Pa · s or more and 100 Pa · s or less at room temperature of 25 ° C. The insulating paste according to any one of claims 1 to 9.
The viscosity ratio of the insulating paste at room temperature of 25 ° C. when the viscosity measured at a shear rate of 1 [1 / s] is η1 and the viscosity measured at a shear rate of 5 [1 / s] is η5. An insulating paste having a viscosity index of (η1 / η5) of 1.0 or more and 3.0 or less. The insulating paste according to any one of claims 1 to 10.
An insulating paste comprising the thermoplastic elastomer composition for forming one or more elastomers selected from the group consisting of silicone rubber, urethane rubber, and fluororubber. The insulating paste according to any one of claims 1 to 11.
An insulating paste in which the elastomer composition contains a silicone rubber-based curable composition. The insulating paste according to any one of claims 1 to 12.
An insulating paste having a content of the elastomer composition of 5% by mass or more and 50% by mass or less with respect to the entire insulating paste. The insulating paste according to any one of claims 1 to 13.
An insulating paste further comprising silica particles (C). The insulating paste according to claim 14 , wherein the insulating paste is used.
An insulating paste in which the content of the silica particles (C) is 1% by mass or more and 50% by mass or less with respect to the entire insulating paste. The insulating paste according to any one of claims 1 to 15.
An insulating paste in which the solvent for measurement is tetradecane.

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