Electro-conductive pressure-sensitive adhesive tape, an electronic member, and a pressure-sensitive adhesive

1. An electro-conductive pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer, wherein

the pressure-sensitive adhesive layer contains a resin component and electro-conductive particles,

the electro-conductive particles are spherical,

the electro-conductive particles have at least one peak top existing in a particle size range from about 15 μm or more to about 50 μm or less, and at least one further peak top existing in a particle size range from about 1 μm or more to about 12 μm or less in a particle size distribution curve thereof,

the electro-conductive particles are contained in the pressure-sensitive adhesive layer in an amount of 55.5% or more but 80 mass % or less, and

the electro-conductive particles have true densities in a level of larger than zero but smaller than 8 g/cm 3 ,

the electro-conductive particles are glass or polymer particles coated with metal on surfaces of the glass or polymer particles,

the electro-conductive particles include large electro-conductive particles comprising particles with a particle size in a range from about 15 μm or more to about 50 μm or less, and small electro-conductive particles comprising particles with a particle size in a range from about 1 μm or more to about 12 μm or less, and

a ratio (X1/X2) of a content (X1) of the large electro-conductive particles to a content (X2) of the small electro-conductive particles in the pressure-sensitive adhesive layer is 1.1 or more but 8.0 or less.

2. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive layer includes an acrylic resin as the resin component.

3. The electro-conductive pressure-sensitive adhesive tape according to claim 2 , wherein a content of the acrylic resin over a total mass of the pressure-sensitive adhesive is 20 mass % to 60 mass %.

4. The electro-conductive pressure-sensitive adhesive tape according to claim 2 , wherein the acrylic resin includes a polymer containing any of (meth)acrylic acid methyl, (meth)acrylic acid ethyl, (meth)acrylic acid n-butyl, (meth)acrylic acid isobutyl, (meth)acrylic acid s-butyl, (meth)acrylic acid t-butyl, (meth)acrylic acid hexyl, (meth)acrylic acid octyl, (meth)acrylic acid 2-ethylhexyl, (meth)acrylic acid isooctyl, (meth)acrylic acid nonyl, (meth)acrylic acid isononyl, (meth)acrylic acid decyl, and (meth)acrylic acid isodecyl as a monomer component.

5. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive layer further contains polymerization initiator.

6. The electro-conductive pressure-sensitive adhesive tape according to claim 5 , wherein the polymerization initiator includes at least one selected from azo polymerization initiators, peroxide polymerization initiators, redox polymerization initiators, benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, and acylphosphine oxide photo-polymerization initiators.

7. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the resin component includes a polymerized product of a solventless pressure-sensitive adhesive composition.

8. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive further contains a polymer containing a polyfunctional monomer as a monomer component.

9. The electro-conductive pressure-sensitive adhesive tape according to claim 8 , wherein the polyfunctional monomer contains any of hexanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylol methane tri(meth)acrylate, allyl(meth)acrylate, vinyl(meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate.

10. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive layer has a thickness in a range from 15 μm or more to 100 μm or less.

11. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive layer has an electric resistance value smaller than 6Ω in thickness direction with an adhesive area of 5 mm×5 mm.

12. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive layer has pressure-sensitive adhesive force of at least 3 N/20 mm or more to an adherend made of SUS plate.

13. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the metal is any of nickel, iron, chromium, cobalt, aluminum, antimony, molybdenum, copper, silver, platinum, and gold.

14. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein

the large electro-conductive particles have true densities in a level of 2.7 g/cm 3 or more but smaller than 8 g/cm 3 , and

the small electro-conductive particles have true densities in a level of 3.9 g/cm 3 or more but smaller than 8 g/cm 3 .

15. The electro-conductive pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive layer has an electric resistance value smaller than 6Ω in thickness direction with an adhesive area of 5 mm×5 mm, and pressure-sensitive adhesive force of at least 3 N/20 mm or more to an adherend made of SUS plate.