JP2001279192A - Substrate-free conductive pressure-sensitive adhesive tape / sheet and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-substrate conductive pressure-sensitive adhesive tape / sheet having good basic adhesive properties such as adhesive strength and high-temperature holding power and excellent conductivity, and a method for producing the same. SOLUTION: A photo-curing type mainly composed of a (meth) acrylic acid alkyl ester monomer, a polar group-containing monomer, an acrylic polymer having a photoactive functional group, a photopolymerization initiator and conductive particles. Using a conductive pressure-sensitive adhesive, in a non-substrate conductive double-sided pressure-sensitive adhesive tape sheet prepared by polymerization by light irradiation, as an acrylic high molecular weight material having a photoactive functional group, the weight average molecular weight is 200,000 to 3,000,000 Yes, a high molecular weight substance having a photoactive functional group content of 0.001 to 0.5 meq / g is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic-based non-base conductive tape / sheet and a method for producing the same.

[0002]

2. Description of the Related Art Electromagnetic shielding materials for containers housing electronic devices such as computers and communication devices, grounding wires for electric components, and various types of joining materials such as materials for preventing ignition by sparks based on static electricity such as triboelectricity, etc. A conductive pressure-sensitive adhesive tape having properties and adhesive simplicity such as a pressure-sensitive adhesive tape is used.

In recent years, in industries such as the electric and electronic fields and the automobile industry, as products have become more sophisticated, more functional, and more diversified, adhesives and pressure-sensitive adhesives used for joining parts have high heat resistance. Demands for properties, high adhesiveness, high reliability, etc. are increasing. In particular, in recent years, from the viewpoint of improving workability and work environment,
Various components are often joined using a tape-shaped or sheet-shaped pressure-sensitive adhesive ("pressure-sensitive adhesive" is referred to as "adhesion") instead of a liquid adhesive. Also, in the field of conductive adhesive tapes and sheets, with the miniaturization of parts and devices, the demand for thinning is also strict, and in order to improve adhesion and conductivity with adherends, as described above, There is a demand for the development of a so-called baseless conductive pressure-sensitive adhesive tape / sheet having characteristics and not using a support.

[0004] As the conductive adhesive tape used in the electric and electronic fields, a conductive adhesive obtained by dispersing conductive particles such as metal powder in an adhesive substance has been used. Coating on one side of a conductive substrate has been used, and as the conductive substrate, copper foil, aluminum foil, stainless steel foil, nickel foil, etc., as the conductive particles, copper powder, silver powder, Nickel powder, aluminum powder and the like are used. In the case of producing a conductive double-sided pressure-sensitive adhesive tape, one obtained by applying the conductive pressure-sensitive adhesive on both surfaces of the conductive substrate is used.

[0005] However, in a conventional conductive adhesive tape in which a conductive adhesive is applied to such a conductive substrate, the thickness of the adhesive tape is large and the adhesive tape is hard. As a result, there is a problem in the adhesion to the adherend. In addition, it cannot cope with miniaturization required for joining electric and electronic components, and a solution is desired.

[0006] Conventionally, as a method for producing an adhesive tape, a water-based adhesive such as a solvent-type adhesive or an emulsion is applied onto a substrate, and then the solvent or water is volatilized by heating to crosslink the adhesive. -A curing method has been adopted.

However, solvent-based pressure-sensitive adhesive tapes which are conventionally used and which are cured by heating have problems in heat resistance and reliability after bonding.
No. 784, Japanese Unexamined Patent Publication No. 9-137142 and the like have developed ultraviolet-curable pressure-sensitive adhesive tapes.

[0008]

However, even with the UV-curable pressure-sensitive adhesive tape described in the above-mentioned publication, especially when the thickness of the pressure-sensitive adhesive tape is small, the adhesive basic properties such as adhesive force and high-temperature holding force are good. In addition, it is difficult to obtain a non-substrate conductive pressure-sensitive adhesive tape having excellent conductivity, and development of materials and processes for solving the problem has been desired.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a non-substrate conductive material having good basic adhesive properties such as adhesive strength and high-temperature holding power and excellent electrical conductivity. An object of the present invention is to provide a pressure-sensitive adhesive tape / sheet and a method for producing the same.

[0010]

In order to achieve the above object, the present invention provides an alkyl (meth) acrylate monomer, a polar group-containing monomer, and an acrylic high molecular weight having a photoactive functional group. Non-base conductive adhesive tapes / sheets prepared using a photocurable conductive adhesive obtained by dispersing conductive particles such as metal powder in a photocurable adhesive containing a polymer and a photopolymerization initiator as main components In the above, the weight average molecular weight of the acrylic polymer having a photoactive functional group, 200,000 ~
3 million, the content of the photoactive functional group is 0.001 to
0.5 meq / g, and the content of the conductive particles with respect to 100 parts by weight of the photocurable adhesive in the photocurable conductive adhesive is 10 to 200 parts by weight.

[0011] In the above method for producing a substrate-free conductive pressure-sensitive adhesive tape / sheet, the photocurable conductive pressure-sensitive adhesive is applied on a sheet substrate to a thickness of 5 to 500 µm to form a photocurable conductive tape. An adhesive layer is formed, and the photocurable conductive adhesive layer is cured by light irradiation.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In order to achieve the above object, the present inventors have studied various materials and processes and found that (meth) acrylic acid alkyl ester monomer, polar group-containing monomer, photoactive functional group Polymerization by light irradiation using a conductive photo-curable adhesive in which conductive particles such as metal powder are dispersed in a photo-curable pressure-sensitive adhesive mainly composed of an acrylic high molecular weight material and a photopolymerization initiator having Even if the tape thickness is small, the adhesive strength and
It was confirmed that the adhesive properties such as the high-temperature holding power were good and the conductivity was also excellent.

The acrylic high molecular weight compound having a photoactive functional group used herein has a weight average molecular weight of 200,000 to 3,000,000 and a content of the photoactive functional group of 0.001 to 0,0. A non-substrate conductive pressure-sensitive adhesive tape prepared using a conductive light-curable pressure-sensitive adhesive in which conductive particles are dispersed in a light-curable pressure-sensitive adhesive containing the same is found to be good. It was confirmed that the sheet exhibited excellent properties such as adhesive strength, high-temperature holding power, and conductivity.

That is, by using the non-substrate conductive pressure-sensitive adhesive tape / sheet made of the conductive light-curable pressure-sensitive adhesive of the present invention, a bond having good adhesive basic properties such as adhesive strength and high-temperature holding power and good conductivity. Is obtained. In addition, the thickness of the pressure-sensitive adhesive tape / sheet can be reduced, and since there is no base material, the adhesiveness to the adherend is excellent, and electrical bonding suitable for small electric / electronic parts can be obtained. .

Hereinafter, the materials used in the present invention and the method for producing the pressure-sensitive adhesive tape / sheet will be described.

The acrylic high molecular weight material having a photoactive functional group is used for improving the heat resistance of the pressure-sensitive adhesive tape / sheet, particularly the characteristics such as high-temperature holding power, and the workability such as coating property. Used to improve
The acrylic high molecular weight material having a photoactive functional group used in the present invention has a weight average molecular weight of 200,000 to 300.
Acrylic high molecular weight materials having a photoactive functional group content of 0.001 to 0.5 meq / g are preferred.

As a method for introducing the photoactive functional group into the acrylic high molecular weight compound, generally, a hydroxyl group in a side chain of the acrylic high molecular weight compound is converted to an isocyanate compound having a (meth) acryloyloxy group (for example, -Methacryloyloxyethyl isocyanate). In this way, an acrylic high molecular weight substance having a photoactive functional group such as a (meth) acryloyloxy group can be obtained. However, the introduction method is not particularly limited.

When the weight-average molecular weight of the acrylic high molecular weight compound having a photoactive functional group is smaller than 200,000,
In order to obtain a high-viscosity adhesive composition of several thousand to several tens of thousands cp in consideration of coatability and the like, it is necessary to increase the amount of the acrylic polymer having a photoactive functional group. As a result, the adhesive tape has both excellent adhesive properties (specifically, adhesive strength of 3.5N / 10mm or more to a stainless steel substrate) and heat resistance (specifically, holding power at 150 ° C or more). No, not preferred.

When the weight-average molecular weight is more than 3,000,000, the properties of the pressure-sensitive adhesive tape are not particularly problematic, but it is difficult to mass-produce an acrylic high molecular weight substance, which is not preferable.

When the content of the photoactive functional group of the acrylic polymer having a photoactive functional group is less than 0.001 meq / g, the high-temperature holding power of the pressure-sensitive adhesive tape deteriorates. When the content of the photoactive functional group is more than 0.5 meq / g, the adhesive strength of the pressure-sensitive adhesive tape becomes low, which is not preferable in any case. The amount of the acrylic polymer having a photoactive functional group in the pressure-sensitive adhesive composition is adjusted according to the desired pressure-sensitive adhesive properties and the viscosity at the time of coating. 5-
Used at 50% by weight.

The main component of the acrylic high molecular weight compound having a photoactive functional group is usually a copolymer of a (meth) acrylic acid alkyl ester monomer and a polar group-containing monomer, for example, an acrylic polymer. Copolymers of 2-ethylhexyl acrylate and 2-hydroxyethyl methacrylate, terpolymers of isooctyl acrylate, acrylic acid and 2-hydroxyethyl methacrylate, and the like are used, but are not particularly limited thereto. Not something.

The alkyl (meth) acrylate monomers used in the present invention include, for example, ethyl group, propyl group, butyl group, pentyl group, hexyl group, 2-ethylhexyl group, octyl group, Usually, esters of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms, such as an isooctyl group, a nonyl group, an isononyl group, and a decyl group, are exemplified. The above-mentioned alkyl (meth) acrylate is used alone or in combination of two or more. In the present invention,
Part of the alkyl (meth) acrylate may be replaced with a copolymerizable monomer such as vinyl acetate.

The above-mentioned polar group-containing monomer used in the present invention includes acrylic acid, methacrylic acid, itaconic acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl acrylate, acrylonitrile, methacrylic acid. Ronitrile, N-vinyl-2
-Polymerizable unsaturated monomers having a polar group such as a carboxyl group, a hydroxyl group or an amino group in the molecule, such as pyrrolidone.

The compounding amount is 1 to 3 with respect to 99 to 70 parts by weight of the above-mentioned alkyl (meth) acrylate.
It is preferably 0 parts by weight. When the content of the polar group-containing monomer is less than 1 part by weight, the adhesive strength of the pressure-sensitive adhesive tape is reduced, and when the content is more than 30 parts by weight, the pressure-sensitive adhesive property of the pressure-sensitive adhesive tape at low temperature is reduced. In any case, it is not preferable. The polar group-containing monomers described above are used alone or in combination of two or more.

As the above-mentioned photopolymerization initiator, a usual photopolymerization initiator used for radical photopolymerization such as a vinyl group or a (meth) acryloyloxy group is used. For example,
2,2-dimethoxy-1,2-diphenylethane-1-
Benzyldimethyl ketal compounds such as ON (Irgacure 651 from Ciba Specialty Chemicals), 1-hydroxycyclohexyl phenyl ketone (Irgacure 18 from Ciba Specialty Chemicals)
4), α-hydroxyketone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173 of Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino-1- (4
Α-aminoketone compounds such as -morpholinophenyl) butanone-1 (Irgacure 369 from Ciba Specialty Chemicals) and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (Ciba Specialty Chemicals) Irgacure 81
9) and the like, and bis (2,6-dimethoxybenzoyl) -2,4,
Bisacylphosphine oxides such as 4-trimethylpentylphosphine oxide and Darocure 117
1: 3 mixture of Irgacure 1700 with Ciba Specialty Chemicals, bisacylphosphine oxide such as bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and Irgacure 184 1: 1 mixture with Irgacure 185 (Ciba Specialty Chemicals)
0), benzoin ethyl ether compounds such as benzoin ethyl ether and benzoin isopropyl ether. In particular, a photopolymerization initiator such as a bisacylphosphine oxide-based compound that generates two or more active species (radicals) from one molecule of the photopolymerization initiator by light irradiation is desirable.

These photopolymerization initiators are preferably used in a proportion of 0.001 to 5 parts by weight based on 100 parts by weight of the photocurable pressure-sensitive adhesive. When the amount is less than 0.001 part by weight, it is difficult to complete the polymerization sufficiently, and when the amount is more than 5 parts by weight, the molecular weight of the obtained pressure-sensitive adhesive polymer becomes small, In particular, the holding power of the pressure-sensitive adhesive tape at high temperatures is reduced, which is not preferable in terms of pressure-sensitive adhesive properties.

The conductive particles used in the present invention include:
Conductive particles such as nickel powder, copper powder, silver powder, aluminum powder, and carbon powder can be used.

In order to obtain high conductivity with a small amount of conductive particles, it is preferable to use a secondary aggregate of conductive particles. Further, in order to prevent sedimentation of the conductive particles, various anti-settling agents (for example, Disparon # 6650 manufactured by Kusumoto Kasei) may be added.

These conductive particles are preferably used in a proportion of 10 to 200 parts by weight based on 100 parts by weight of the photocurable pressure-sensitive adhesive. If the amount is less than 10 parts by weight, it is difficult to sufficiently exhibit conductivity,
When the amount is more than 200 parts by weight, it is difficult to obtain a sufficient adhesive strength, and in any case, it is not practically preferable as a non-base conductive adhesive tape / sheet.

Further, the photocurable conductive pressure-sensitive adhesive of the present invention
If necessary, about 0.001 to 5 parts by weight of a photopolymerizable compound such as a polyfunctional acrylic (methacrylic) -based monomer may be added to 100 parts by weight of the adhesive composition excluding the conductive particles. Examples of such a photopolymerizable compound include hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and dipentaerothritol hexa. Examples include (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, and the like.

Further, the non-substrate conductive adhesive tape of the present invention
To the photocurable conductive pressure-sensitive adhesive for producing the sheet, a tackifier such as a rosin-based resin, a terpene-based resin, or a petroleum resin, which is usually used for an acrylic resin, may be added.

The photocurable conductive pressure-sensitive adhesive of the present invention may further contain commonly used additives such as a thickener, a thixotropic agent, and a filler. Examples of the thickener include acrylic rubber and epichlorohydrin rubber, and examples of the thixotropy agent include ultrafine silica (such as Aerosil 300 manufactured by Aerosil Japan). As the filler, calcium carbonate, titanium dioxide, inorganic particles such as silicon dioxide, nylon beads, acrylic beads, organic particles such as silicone beads, glass balloon,
Examples include inorganic hollow particles such as alumina balloons, organic hollow particles such as acrylic balloons and vinylidene chloride balloons, and organic or inorganic short fibers such as polyester, nylon, rayon, and glass. These are added in order to improve mechanical properties such as stress relaxation of the pressure-sensitive adhesive tape / sheet, and are used within a range that does not impair photocurability and the like.

The above-mentioned photocurable conductive pressure-sensitive adhesive is in a liquid state, and is coated on a sheet substrate such as a polyester film subjected to a release treatment by a roll coater or a die coater, and then polymerized by light irradiation. As a result, a substrate-free conductive pressure-sensitive adhesive tape / sheet is obtained. When the photocurable conductive pressure-sensitive adhesive is polymerized, the polymerization reaction is inhibited by oxygen in the air or oxygen dissolved in the pressure-sensitive adhesive. Irradiation is performed in an atmosphere replaced by an inert gas. A tin salt compound having a deoxidizing effect, such as stannous octoate or triisodecyl phosphite, or a phosphorus-based compound may be added to suppress the inhibition of curing by oxygen.

Hereinafter, the method for producing a base-free conductive pressure-sensitive adhesive tape / sheet of the present invention will be specifically described. However, the non-substrate conductive pressure-sensitive adhesive tape / sheet of the present invention is not limited to one manufactured by this method.

First, the (meth) acrylic acid alkyl ester monomer and the polar group-containing monomer are mixed in a predetermined blending amount, and the acrylic polymer having a photoactive functional group and the conductive polymer are mixed. The conductive particles and the photopolymerization initiator are added in a predetermined amount, sufficiently stirred and mixed to obtain a uniform conductive pressure-sensitive adhesive. In this case, the viscosity of the conductive pressure-sensitive adhesive at 25 ° C. is preferably 1,000 to 50,000 cp in terms of coating. The viscosity is adjusted according to the thickness required for the tape sheet.

If necessary, the above-mentioned conductive adhesive may be added to the above-mentioned polyfunctional (meth) acrylic monomer,
A thixotropic agent, a filler and the like may be added.

The conductive pressure-sensitive adhesive thus prepared is applied to a predetermined thickness of usually 5 to 500 μm on a sheet substrate such as a polyester film subjected to a release treatment. Next, under a nitrogen atmosphere, or under a condition in which a transparent polyester-coated film is stacked and air is blocked, the ultraviolet intensity at 365 nm is about 0.1 to
Irradiate ultraviolet rays of 10 mW / cm ² for 20 seconds to 5 minutes,
The conductive pressure-sensitive adhesive layer is cured, and the baseless conductive pressure-sensitive adhesive tape
Get a sheet.

The non-substrate conductive pressure-sensitive adhesive tape / sheet of the present invention is obtained in this manner. When the tape / sheet is bonded to an adherend such as an electric or electronic component, excellent pressure-sensitive adhesive properties and conductivity are obtained. Is shown.

[0039]

EXAMPLES The non-substrate conductive pressure-sensitive adhesive tape / sheet of the present invention and the method for producing the same will be specifically described with reference to examples of the present invention. However, the non-substrate conductive pressure-sensitive adhesive tape / sheet of the present invention and the method for producing the same are not limited thereto. It should be noted that “parts” in the description of the examples and comparative examples of the embodiments represents parts by weight. Example 1 2-Ethylhexyl acrylate having a weight average molecular weight of 700,000 and a photoactive functional group content of 0.01 meq / g was used as a main component in 63 parts of 2-ethylhexyl acrylate and 7 parts of acrylic acid. Acrylic high molecular weight body 30
Parts, 1,6-hexanediol diacrylate 0.05
Parts, 30 parts of nickel powder # 287 (manufactured by Nikko Fine Products) and 0.3 part of a photopolymerization initiator Irgacure 819 (manufactured by Ciba Specialty Chemicals) were mixed well, and the mixture had a viscosity of 2 at 25 ° C. 000c
p was obtained.

This adhesive was coated on a 50 μm-thick polyester film having been subjected to a release treatment by a comma coater, and a 50 μm-thick polyester film having been subjected to a release treatment was overlaid thereon so as to prevent air bubbles from entering.
m was irradiated with ultraviolet light having an ultraviolet intensity of 3 mW / cm ² for 2 minutes to obtain a 50 μm-thick non-substrate conductive pressure-sensitive adhesive tape sheet.

The adhesive strength of the non-base conductive adhesive tape / sheet to the stainless steel plate was 4.7 N / 10 mm, and in a holding force test (load: 1 kg) at 40 ° C./24 hours or 180 ° C./1 hour. No slippage or drop was observed, indicating excellent adhesiveness and heat resistance. The ball tack of this conductive adhesive tape / sheet (angle: 30 °)
Was 3 or less.

When the electric resistance value of this non-substrate conductive pressure-sensitive adhesive tape / sheet was measured, it was found to be 5.0 × 10 ⁻² Ω / 25 mm.
Angle (in terms of volume resistance value, 63 Ω · cm)
It was confirmed that the film had conductivity and had a sufficient function as a conductive pressure-sensitive adhesive tape / sheet. Example 2 63 parts of isooctyl acrylate and 7 parts of acrylic acid were composed mainly of 2-ethylhexyl acrylate having a weight average molecular weight of 800,000 and a photoactive functional group content of 0.02 meq / g. 30 parts of an acrylic high molecular weight body,
0.05 parts of 1,6-hexanediol diacrylate,
Nickel powder # 287 (manufactured by Nikko Fine Products) 5
Part 0 and Irgacure 819 (Ciba Specialty
Chemicals) (0.3 parts) and mix well.
A uniform pressure-sensitive adhesive having a viscosity of 2,500 cp at 5 ° C. was obtained.

This adhesive was applied on a 50 μm-thick polyester film having been subjected to a peeling treatment by a doctor coater, and a 50 μm-thick polyester film having been subjected to a peeling treatment was overlaid thereon so as to prevent bubbles from entering.
UV light with an intensity of 3 mW / cm ² at ² nm
For 70 minutes to obtain a 70 μm thick non-substrate conductive pressure-sensitive adhesive tape sheet.

The adhesive strength of this non-base conductive adhesive sheet to a stainless steel plate was 5.9 N / 10 mm,
In a holding force test (load: 1 kg) at / 24 hours or 180 ° C / 1 hour, no slippage or drop was observed, and excellent adhesiveness and heat resistance were exhibited. The pressure-sensitive adhesive sheet had a ball tack (angle: 30 °) of 3 or less.

When the electric resistance value of this conductive pressure-sensitive adhesive tape / sheet was measured, it was found to be 7.0 × 10 ⁻² Ω / 25 mm square (converted to a volume resistance value of 88 Ω · cm). It was confirmed that the film had a sufficient function as a conductive pressure-sensitive adhesive tape / sheet. [Examples 3 to 13] In the same manner as in Examples 1 and 2,
A non-substrate conductive pressure-sensitive adhesive tape / sheet was produced under the composition and production conditions shown in Table 1. In Table 1, all photopolymerization initiators used were Irgacure 819 and 0.3 parts, and 0.05 parts of 1,6-hexanediol diacrylate was added to all compositions. The light irradiation condition was to irradiate ultraviolet rays having an ultraviolet intensity of 3 mW / cm ² for 2 minutes.

Table 2 shows the measurement results of the adhesive strength, holding power, and electric resistance of these non-base conductive adhesive tapes / sheets, and all showed excellent adhesive properties, heat resistance and conductivity. In addition, mass productivity such as coatability, film formability, and curability when producing a non-base conductive adhesive tape / sheet was also good.

[0047]

[Table 1]

[0048]

[Table 2] [Comparative Example 1] Acrylic high-molecular-weight polymer 30 having a weight average molecular weight of 700,000 and 2-ethylhexyl acrylate containing no photoactive functional group as a main component in 63 parts of 2-ethylhexyl acrylate and 7 parts of acrylic acid Part, 1,6-hexanediol diacrylate 0.05 part, nickel powder # 2
87 (manufactured by Nikko Fine Products) and 0.3 parts of Irgacure 819 (manufactured by Ciba Specialty Chemicals) are added and mixed well to obtain a uniform adhesive having a viscosity of 3,000 cp at 25 ° C. Was.

This pressure-sensitive adhesive was applied on a 50 μm-thick polyester film which had been subjected to a release treatment.
Ultraviolet light having an intensity of 1 mW / cm ² at 365 nm was irradiated for 2 minutes to obtain a 50 μm-thick non-substrate conductive pressure-sensitive adhesive tape sheet.

The adhesive strength of the adhesive tape / sheet to the stainless steel plate is 7.0 N / 10 mm, and the ball tack is 3
Hereinafter, although the electric resistance value was 8.0 × 10 ⁻² Ω / 25 mm square, it fell in 10 minutes in a holding force test (load: 1 kg) at 40 ° C., and it was found that the holding force was inferior. [Comparative Example 2] 2-Ethylhexyl acrylate having a weight average molecular weight of 800,000 and a photoactive functional group content of 0.02 meq / g was used as a main component in 63 parts of isooctyl acrylate and 7 parts of acrylic acid. 30 parts of an acrylic high molecular weight body,
0.05 parts of 1,6-hexanediol diacrylate and 0.3 parts of Irgacure 819 (manufactured by Ciba Specialty Chemicals) were sufficiently mixed to obtain a uniform pressure-sensitive adhesive having a viscosity of 3,000 cp at 25 ° C. .

This adhesive is applied on a 50 μm-thick polyester film subjected to a release treatment, and a 50 μm-thick transparent polyester film subjected to a release treatment is laminated thereon so as to prevent air bubbles from entering. Irradiate with ultraviolet light having an intensity of 3 mW / cm ² for 2 minutes.
A thick non-base pressure-sensitive adhesive sheet was obtained.

The adhesive strength of this adhesive sheet to the stainless steel plate is 7.0 N / 10 mm, the ball tack is 3, 40 ° C.
In a holding force test (load: 1 kg) at / 24 hours or 180 ° C./1 hour, no slippage or drop was observed, and excellent adhesion and heat resistance were exhibited, but the electric resistance value was 5 × 10 5
¹³ Ω / 25 mm square, no conductivity, and it was not possible to achieve both excellent adhesion, holding power and conductivity.

[0053]

As described above, the present invention provides an alkyl (meth) acrylate monomer, a polar group-containing monomer, an acrylic high molecular weight material having a photoactive functional group, and a photopolymerization initiator. In a non-substrate conductive pressure-sensitive adhesive tape / sheet produced using a photocurable conductive pressure-sensitive adhesive obtained by dispersing conductive particles such as metal powder in a photocurable pressure-sensitive adhesive mainly containing The weight-average molecular weight of the acrylic high-molecular substance having a group is 200,000 to 3,000,000, and the content of the photoactive functional group is 0.001 to 0.5 meq / g;
In addition, the content of the conductive particles with respect to 100 parts by weight of the photocurable adhesive in the photocurable conductive adhesive is 10%.
By setting the content to 200 parts by weight, it is possible to obtain a non-substrate conductive pressure-sensitive adhesive tape / sheet having good adhesive basic properties such as adhesive strength and high-temperature holding power and excellent conductivity.

The present invention also relates to a method for producing the above-mentioned non-base conductive adhesive tape / sheet, wherein the photo-curable conductive adhesive is coated on a sheet substrate to a thickness of 5 to 500 μm to obtain a light-sensitive material. Form a curable conductive pressure-sensitive adhesive layer, by curing the photocurable conductive pressure-sensitive adhesive layer by light irradiation,
The pressure-sensitive adhesive tape / sheet can be manufactured with good mass productivity.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuo Naume 3819 Noboru Noto, Tama-ku, Kawasaki-shi, Kanagawa F-Term in Sliontec Co., Ltd. (Reference) 4J004 AA01 AA10 AA17 AA18 AB01 AB07 CC02 FA05 4J040 FA141 FA231 GA05 GA07 GA13 GA14 GA15 GA18 HB13 HB19 HC09 HD27 JA09 JB08 JB09 JB10 KA03 KA13 KA32 LA01 LA06 LA08 LA09 5G301 DA10 DA18 DA42 DD03 DD08 DE01 5G307 HA01 HB01 HB03 HC01

Claims (2)

[Claims] 1. A photo-curable pressure-sensitive adhesive comprising a (meth) acrylic acid alkyl ester monomer, a polar group-containing monomer, an acrylic polymer having a photoactive functional group and a photopolymerization initiator as main components. In a non-substrate conductive pressure-sensitive adhesive tape / sheet prepared using a photocurable conductive pressure-sensitive adhesive in which conductive particles are dispersed, the weight average molecular weight of the acrylic high molecular weight material having the photoactive functional group is 200,000. And the content of the photoactive functional group is 0.001 to 0.5 meq / g.
And the photocurable conductive pressure-sensitive adhesive is 10 parts by weight of the conductive particles per 100 parts by weight of the photocurable pressure-sensitive adhesive.
A non-substrate conductive pressure-sensitive adhesive tape / sheet characterized by containing -200 parts by weight. 2. The photo-curable conductive pressure-sensitive adhesive according to claim 1 is applied to a thickness of 5 to 500 μm on a sheet substrate to form a photo-curable conductive pressure-sensitive adhesive layer. A method for producing a substrate-free conductive pressure-sensitive adhesive tape / sheet, which is produced by curing a curable conductive pressure-sensitive adhesive layer.