Adhesive composition

Disclosed is an adhesive composition which contains (1) a polymer selected from acrylonitrile/butadiene copolymers, carboxyl group-containing acrylonitrile/butadiene copolymers, acrylic rubbers, urethane rubbers, chloroprene rubbers, chlorosulfonated polyethylene, ethylene/vinyl acetate copolymers, ethylene/acrylic acid or its ester or metal salt copolymers, ethylene/methacrylic acid ester or metal salt copolymers, thermoplastic polyurethanes, saturated polyesters and polyamides, (2) an epoxy acrylate resin, (3) an acrylic or methacrylic monomer having at least two different functional groups and/or an acrylic or methacrylic monomer of the formula: ##STR1## wherein R.sub.1 is H or CH.sub.3 and R.sub.2 is (C.sub.1 -C.sub.18) alkyl or an organic residue containing an aromatic hydrocarbon ring or a heterocyclic ring, (4) an organic peroxide and (5) an imidazole or an amino compound containing at least one tertiary amino group. The adhesive composition may further contain (6) a phosphorus-containing acrylate or methacrylate and/or a nitrogen-containing acrylate or methacrylate, and/or (7) an electroconductive material selected from carbon black having a surface area of 125 to 260 m.sup.2 /g and a DBP oil absorption of 100 to 200 cc/100 g, Ketjenblack, lamp black, acetylene black and graphite, and a cut carbon fiber and fine powders of aluminum, nickel, copper and zinc, having a size of not larger than 200 mesh. A structural adhesive is prepared by impregnating, spread-coating or laminating a strand mat, surface mat, cloth, nonwoven fabric or victoria lawn, composed of a glass fiber, a glass fiber/organic fiber composite, an organic fiber or a carbon fiber with the adhesive composition.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
The present invention relates to a structural adhesive for use in bonding 
metals, paper, plastics and inorganic materials. More particularly, it 
relates to a structural adhesive having a good bonding property even to a 
surface on which a rust preventive oil or processing oil remains, the 
adhesive also having a high shearing force and a bonding force, and having 
an excellent flexural strength even after heating and curing. The adhesive 
also has an excellent rust preventive effect after bonding. 
(2) Description of the Related Art 
As known structural adhesives, there can be mentioned epoxy resin type 
adhesives, phenolic type adhesives, polyurethane type adhesives, 
structural acrylic adhesives and anaerobic structural adhesives. As the 
oil-absorbing adhesive capable of bonding to an oil-adhering metal 
surface, chloroprene type mastic adhesives having a non-volatile component 
content of at least 67% and vinyl chloride type mastic adhesives having a 
non-volatile component content of at least 92% are used. The adhesive 
power of these adhesives is low on an oily surface or, even if the 
adhesive bonds to the oily surface, the bonding strength is not as high as 
the bonding strength of the structural adhesive. Furthermore, polyurethane 
type adhesives, structural acrylic adhesives and anaerobic structural 
adhesives have a problem in that, when these adhesives are fixed to the 
surfaces of adherents or the bonded adherents are heated after fixation 
while being maintained in the vertical state, the adherents are readily 
moved out of position by a slight shock or vibration. Accordingly, it is 
necessary to secure the adherents by spot welding or clipping until a 
sufficient bonding strength is manifested. 
Normal temperature curing type adhesives have been reported. For example, 
Japanese Unexamined Patent Publication No. 50-158624 discloses an adhesive 
composition comprising a liquid formed by incorporating a liquid 
chloroprene polymer with an epoxy resin and a liquid comprising a 
polyamide resin, a xylene resin being incorporated in at least one of the 
two liquids. However, this adhesive composition exhibits a poor bonding 
strength at elevated temperatures. 
Polyurethane type adhesives are effective for bonding mortar, slate and 
plywood, but, when used for bonding metal adherents, the adhesives per se 
readily bubble due to the generation of carbon dioxide gas during the 
reaction of NCO groups and, therefore, the bonding strength is poor. In 
cyanoacrylate type adhesives, there is no substantial reduction of the 
bonding power at temperatures ranging from room temperature to about 
90.degree. C., but if the temperature exceeds this range, the bonding 
power is abruptly reduced and the resistance against peeling by bending is 
poor. Moreover, since the manufacturing cost is high, these adhesives have 
little general-purpose utility. 
A structural adhesive having a low electric resistance has not been 
developed. Accordingly, when metal plates are bonded by using conventional 
structural adhesives and electrodeposition coating is carried out on the 
bonded metal plates, electrodeposition is possible only on the metal 
plates because they are electrically conductive, but since most of the 
structural adhesives have an electric resistance higher than 10.sup.8 
.OMEGA.-cm, no electric current flows through the adhesives or, if any 
electric current flows, the quantity is very small. Therefore, 
electrodeposition coating cannot be effected in the vicinity of the 
adhesives or in the bonding interfaces. Accordingly, the generation and 
growth of rust are readily caused at bonding points of the metals and in 
the vicinities thereof. 
SUMMARY OF THE INVENTION 
It is a primary object of the present invention to eliminate the foregoing 
defects of the conventional techniques and provide a structural adhesive 
for bonding metals to each other or a metal to paper, plastics or 
inorganic materials, which adhesive shows an excellent fixing property 
even if oil or the like remains on the surface of adherents and manifests 
a high bonding strength after curing and which prevents the formation of 
rust on the bonded surface. 
Another object of the present invention is to provide an electrically 
conductive adhesive which has a low electric resistance and to which 
electrodeposition coating is possible, and which can, therefore, control 
the generation and growth of rust. 
In accordance with one fundamental aspect of the present invention, there 
is provided an adhesive composition which comprises (1) at least one 
polymer having polar groups, which is selected from the group consisting 
of acrylonitrile/butadiene copolymers, carboxyl group-containing 
acrylonitrile/butadiene copolymers, acrylic rubbers, urethane rubbers, 
chloroprene rubbers, chlorosulfonated polyethylene, ethylene/vinyl acetate 
copolymers, ethylene/acrylic acid or its ester or metal salt copolymers, 
ethylene/methacrylic acid ester or metal salt copolymers, thermoplastic 
polyurethanes, saturated polyesters and nylons, (2) at least one epoxy 
acrylate resin, (3) an acrylic or methacrylic monomer having at least two 
different functional groups and/or an acrylic or methacrylic monomer 
represented by the following general formula: 
##STR2## 
wherein R.sub.1 is H or CH.sub.3, and R.sub.2 is an alkyl group having 1 
to 18 carbon atoms or an organic residue containing an aromatic 
hydrocarbon ring or a heterocyclic ring, (4) an organic peroxide and (5) 
an imidazole or an amino compound containing at least one tertiary amino 
group. This adhesive composition may further comprise, as an optional 
component, (6) at least one member selected from the group consisting of 
mono(2-methacryloyloxyethyl) acid phosphate, mono(2-acryloyloxyethyl) acid 
phosphate and nitrogen-containing acrylates and methacrylates. 
In accordance with another aspect of the present invention, there is 
provided a structural adhesive obtained by impregnating, spread-coating or 
laminating a strand mat, surface mat, cloth, nonwoven fabric or victoria 
lawn composed of a glass fiber, a glass fiber/organic fiber composite, an 
organic fiber or a carbon fiber with an adhesive composition comprising 
the above-mentioned components (1) through (5) and optionally the 
component (6). 
In accordance with still another aspect of the present invention, there is 
provided an electrically conductive adhesive composition which comprises 
the above-mentioned components (1) through (5), optionally the component 
(6), and (7) at least one member selected from carbon black having a 
surface area of 125 to 260 m.sup.2 /g as determined by the N.sub.2 
adsorption method and DBP oil absorption of 100 to 200 cc/100 g, 
Ketjenblack, lamp black, acetylene black and graphite and/or at least one 
member selected from a cut carbon fiber and fine powders of aluminum, 
nickel, copper and zinc having a size not larger than 200 mesh. 
In accordance with still another aspect of the present invention, there is 
provided an electrically conductive adhesive obtained by impregnating, 
spread-coating or laminating a strand mat, surface mat, cloth, nonwoven 
fabric or victoria lawn composed of a glass fiber, a glass fiber/organic 
fiber composite, an organic fiber or a carbon fiber with an adhesive 
composition comprising the above-mentioned components (1) through (5), 
optionally the component (6), and the component (7). 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The polymer used as the component (1) in the present invention has a 
relatively high polarity and has a compatibility with reactive oligomers 
or monomers used in the components (2), (3) and (6), and a polymer having 
a certain oil resistance, that is, a polymer which is not swollen or only 
slightly swollen with an oil, is preferred. Accordingly, as the elastomer 
that can used, there are mentioned acylonitrile/butadiene copolymers 
(NBR), acrylic rubbers, chloroprene rubbers, hydrine rubbers, 
chlorosulfonated polyethylene, ethylene/vinyl acetate copolymers, 
ethylene/acrylic acid copolymers, ehtylene/acrylic acid ester copolymers, 
ethylene/ methacrylic acid copolymers, ethylene/metal acrylate copolymers, 
ethylene/metal methacrylate copolymers, thermoplastic urethane rubbers, 
saturated polyesters and polyamides. These polymers give the adhesive a 
filmy or sheet-like shape-retainability, give toughness to the adhesive 
per se after curing, and impart flexural and peel strengths to bonded 
composites. 
A polymer having carboxyl group at the terminal or in the molecule is 
preferred as the component (1). For example, Nipol 1072 (supplied by 
Nippon Zeon Co.) and Hycar CTBN 1300X13 (supplied by Goodrich Chemical 
Co.), which contain a carboxyl group, are mentioned as NBR. By using 
polymers of this type singly or in the form of a blend with other 
polymers, the modulus, toughness and compatibility are appropriately 
improved and a good balance is maintained in the properties in the entire 
system of the adhesive. 
The epoxy acrylate resin used as the component (2) is selected from resins 
having terminal acrylic or methacrylic groups, which are obtained by 
modifying various epoxy resins such as bisphenol A type epoxy resins, 
bisphenol F type epoxy resins, polyphenol type epoxy resins, halogenated 
bisphenol type epoxy resins, polyhydric glycidyl ester type epoxy resins 
and peracetate oxidized type epoxy resins with acrylic acid or methacrylic 
acid. The terminal acrylic or methacrylic groups of the component (2) are 
polymerized and crosslinked with an organic peroxide, ultraviolet rays or 
electron beams. The component (2) is a so-called oligomer which is neither 
an elastomer nor a monomer and is a solid or highly viscous liquid. Before 
the reaction, the component (2) has appropriate hardness and stickiness at 
room temperature and prevents sagging of the adhesive on the bonding 
surface, and when it is heated, it gives an appropriate tackiness to the 
adhesive. Since the component (2) has ordinarily at least two functional 
groups, it is effective for crosslinking and is valuable for increasing 
the modulus of the adhesive. 
The molecular weight of the component (2) is preferably 200 to 4000, and 
the component (2) is incorporated preferably in an amount of 20 to 200 
parts by weight per 100 parts by weight of the polar polymer (1). If the 
amount of the incorporated component (2) is smaller than 20 parts by 
weight per 100 parts by weight of the component (1), the modulus is 
reduced. If the amount of the component (2) is larger than 200 parts by 
weight per 100 parts by weight of the component (1), the adhesive becomes 
too hard and the bonding force against peeling or bending is reduced. 
In the present invention, an acrylic or methacrylic monomer having at least 
two different functional groups and/or an acrylic or methacrylic monomer 
represented by the following general formula: 
##STR3## 
wherein R.sub.1 is H or CH.sub.3, and R.sub.2 is an alkyl group having 1 
to 18 carbon atoms or an organic residue containing an aromatic 
hydrocarbon ring or heterocyclic ring, is used as the component (3). 
The acrylic or methacrylic monomer having at least two different functional 
groups increases the cross-linking density of the adhesive and the modulus 
thereof and has a good wettability with the bonding interface. Especially, 
this monomer dissolves or disperses therein oils in various surface 
conditions and yields a cured polymer having an oil resistance. This 
component (3) is characteristic over the epoxy acrylate resin as the 
component (2) in that the molecular portions between the telechelic 
acrylic or methacrylic groups are aliphatic and the component (3) is 
substantially liquid. 
As the acrylic and methacrylic monomer used as the component (3), there can 
be mentioned ethylene glycol diacrylate, ethylene glycol dimethacrylate, 
diethylene glycol diacrylate, diethylene glycol dimethacrylate, 
triethylene glycol diacrylate, triethylene glycol dimethacrylate, 
1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 
1,4-butylene glycol dimethacrylate, 1,6-hexane glycol diacrylate, 
1,6-hexane glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl 
glycol dimethacrylate, trimethylol propane triacrylate, trimethylol 
propane trimethacrylate, trimethylol ethane triacrylate, trimethylol 
ethane trimethacrylate, tetramethylol methane triacrylate, tetramethylol 
methane tetraacrylate, glycidyl acrylate, glycidyl methacrylate, 
2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate. 
It is preferred that the above-mentioned component (3) be incorporated in 
an amount of 5 to 70 parts by weight per 100 parts by weight of the 
elastomer (1). If the component (3) is incorporated in an amount larger 
than 70 parts by weight per 100 parts by weight of the component (1), the 
adhesive becomes too hard and has a poor toughness, and the flexural, peel 
and impact strengths are reduced. If the amount of the component (3) is 
smaller than 5 parts by weight per 100 parts by weight of the component 
(1), the plasticizing effect is low, no effect is exerted on oils, and the 
crosslinking density is low. 
As the component (3), there can also be used an acrylic or methacrylic 
monomer represented by the following general formula: 
##STR4## 
wherein R.sub.1 is H or CH.sub.3, and R.sub.2 is an alkyl group having 1 
to 18 carbon atoms or an organic residue containing an aromatic 
hydrocarbon ring or heterocylic ring. This monomer is polymerized by a 
peroxide to increase the molecular weight. In addition to this 
polymerizing function, this monomer, as well as the above-mentioned 
acrylic or methacrylic monomer having different functional groups, exerts 
functions of showing a good wettability with the bonding interface, 
dissolving and dispersing therein oils in various surface conditions, 
appropriately swelling the polymer and facilitating the reaction of the 
oligomer or this monomer per se in the polymer. The monomer wets the 
surface of the adhesive while swelling the polymer, and is effective for 
manifesting tackiness. Moreover, the acrylic or methacrylic polymer formed 
from this monomer has an excellent oil resistance and hence is little 
swollen or softened by an oil. Note, when a step such as high-temperature 
curing is included, an acrylic monomer having a low vapor pressure is 
used. For example, when the adhesive is passed through a baking step at 
200.degree. C., if the vapor pressure of the acrylic monomer is higher 
than 100 mmHg at 200.degree. C., bubbling is caused at the curing step. If 
bubbling occurs in the adhesive before the curing is completed, the 
bonding strength is reduced. As examples of the acrylic and mahacrylic 
monomers used in the present invention, there can be mentioned C.sub.1 
-C.sub.4 -alkoxyethyl acrylate, C.sub.1 -C.sub.4 -alkoxyethyl 
methacrylate, methoxyethoxyethyl acrylate, methoxyethoxyethyl 
methacrylate, benzyl acrylate, benzyl methacrylate, phenoxyethylacrylate, 
phenoxyethyl methacrylate and tetrahydrofurfuryl acrylate. These monomers 
may be used alone or in combination. 
It is preferred that the monomer of the above general formula as the 
component (3) be incorporated in an amount of 3 to 20 parts by weight per 
100 parts by weight of the component (1). If the amount of this monomer is 
larger than 20 parts by weight per 100 parts by weight of the component 
(1), shrinkage at the time of curing is too large or the adhesive becomes 
hard, the distortion of the bonded adherent is large and warping or 
sinking occurs. 
The phosphorus-containing acrylate or methacrylate and/or the 
nitrogen-containing acrylate or methacrylate used optionally as the 
component (6) in the present invention are effective for bonding to the 
metal surface or attaining the rust-preventing effect after bonding. 
Furthermore, the monomer of this type is effective against oils and is 
included into the polymer by heat-curing to give a cured adhesive that is 
not swollen with an oil or the like. As the monomer of this type, there 
are preferably used mono(2-methacryloyloxyethyl) acid phosphate, 
bis(2-methacryloyloxyethyl) acid phosphate, mono(2-acryloyloxyethyl) acid 
phosphate, bis(2-acryloyloxyethyl) acid phosphate, dimethylaminoethyl 
acrylate, dimethylamino ethyl emthacrylate, diethylaminoethyl acrylate, 
diethylaminoethyl methacrylate, 2-aminoethyl vinyl ether, 
t-butylaminoethyl acrylate, morpholinoethyl acrylate and morpholinoethyl 
methacrylate. 
In the present invention, this component (6) is not an indispensable 
component, but in order to improve the bonding to the metal surface and 
the rust-preventing effect after bonding, it is preferred that the 
component (6) be incorporated. The amount incorporated of the component 
(6) is up to 10 parts by weight, preferably 1 to 10 parts by weight, per 
100 parts by weight of the polymer as the component (1). Even if the 
component (6) is incorporated in an amount exceeding 10 parts by weight 
per 100 parts by weight of the component (1), no substantial increase of 
the effect by incorporation of the component (6) is attained but by 
copolymerization, the crosslinking density becomes too high and the 
adhesive becomes brittle. 
In the present invention, in order to provide an adhesive having a reduced 
electrical insulating property, at least one member selected from carbon 
black having a surface area of 125 to 260 m.sup.2 /g as determined by the 
N.sub.2 adsorption method and a DBP oil absorption of 100 to 200 cc/100 g, 
Ketjenblack, lamp black, acetylene black and graphite and/or at least one 
member selected from a cut carbon fiber and fine powders of aluminum, 
nickel, copper and zinc having a size smaller than 200 mesh is 
incorporated as the component (7). 
The component (7) is mixed with the polymer (1) in advance and then mixed 
with various monomers and oligomers. Note, if the carbon fiber is used in 
the form of a cloth or a mat, different processing methods are adopted. It 
is preferred that the component (7) be used in an amount of 10 to 150 
parts by weight per 100 parts by weight of the polymer as the component 
(1). When the electrically conductive powder is not incorporated, the 
volume resistivity of the adhesive composition is about 10.sup.10 to about 
10.sup.13 .OMEGA.-cm, and the adhesive composition is almost insulative. 
When metals are combined in vehicles, electric appliances and construction 
materials, since these ordinarily adopt bolt-fixing and welding methods 
using metals, electric conduction can be attained between portions in 
contact with each other. However, when an organic adhesive is used, since 
the organic material is generally electrically insulating, upon 
electrodeposition coating, the adhesive-applied portion is not coated. 
This disadvantage is eliminated by incorporation of the component (7) in 
the adhesive. It is known that, in view of the field intensity at the 
electrodeposition coating, it is sufficient if the insulating property is 
such that the resistance value is about 15.sup.5 .OMEGA.-cm or smaller. 
In the adhesive of the present invention, the components (2), (3) and (6), 
each having a double bond, is mixed with the polar polymer as the 
component (1), and then, the organic peroxide as the component (4) is 
added to the mixture. By effecting copolymerization or crosslinking by 
ordinary heating or induction heating using electron beams or 
electromagnetic waves, bonding is accomplished, and an organic peroxide to 
be used is appropriately selected according to heating conditions. As the 
organic peroxide, there can be mentioned ketone type peroxides, diacyl 
peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl 
peresters, percarbonates and silane-containing peroxides. 
The amount of the organic peroxide is preferably 0.1 to 10 parts by weight, 
more preferably 1 to 5 parts by weight, based on 100 parts by weight of 
the polymer component (1). 
When the above-mentioned peroxide is added, a small amount of an imidazole 
or an amino compound containing at least one tertiary amino group is added 
as the component (5) of the present invention. As the component (5), there 
can be mentioned Imidazole 2P4MZ (tradename, 2-phenyl-4-methylimidazole), 
Imidazole C17Z (tradename, 2-heptadecylimidazole), DMP-10 (tradename, 
2-(dimethylaminomethyl) phenol), DMP-30 (tradename, 
2,4,6-tris(dimethylaminomethyl)phenol), DBU (1,8-Diaza-bicyclo(5,4,0) 
undecene-7, 
##STR5## 
triethylene diamine and tetramethylene pentamine. If a compound of this 
type contains a glycidyl group as one of the functional groups, the 
compound acts also as a curing catalyst and hence, this compound is 
preferred. The component (5) is incorporated in an amount corresponding to 
1/3 to 1/20 of the amount of the peroxide (4). 
The structural adhesive of the present invention is obtained by 
impregnating, spread-coating or laminating a strand mat, surface mat, 
cloth, nonwoven fabric or victoria lawn which is composed of a glass 
fiber, a glass fiber/organic fiber composite, an organic fiber or a carbon 
fiber, with an adhesive composition comprising the above-mentioned 
components. When a cloth or nonwoven fabric is used, the strength of the 
sheet-like or film adhesive per se is improved and attachment or handling 
of adherents can be facilitated, and furthermore, the thickness of the 
adhesive layer is advantageously kept uniform. In addition, this cloth or 
nonwoven fabric is highly effective for improving the shear strength or 
peeling force and a well-balanced bonding force can be manifested. The 
texture of the cloth is not particularly critical, and any of plain weave, 
narrowed plain weave, satin weave and twill weave can be used. As the 
material of the cloth, there can be used glass, polyesters, nylons and 
vinylon, and mixtures thereof. A strand mat of glass is especially 
preferred because the entire surface is uniformly impregnated with the 
adhesive, and in view of the manufacturing cost, the strand mat of glass 
is advantageous over the above-mentioned cloth. A chopped strand mat or 
roving mat also is preferably used. 
According to the present invention, by combination and integration of the 
above-mentioned components, there can be provided an adhesive which 
manifests an initial tackiness and has an excellent toughness, an 
appropriate modulus and a high rust-preventing effect. 
As is apparent from the foregoing description, the adhesive composition of 
the present invention comprising the above-mentioned components (1) 
through (5) is sufficiently fixed to a wet surface, especially an oily 
surface, of a steel plate or the like without any washing or cleaning 
treatment, and manifests a strong bondability by heating and curing. If 
the component (6) is further incorporated, the bonding to a metal is 
enhanced and the rust-preventing effect after bonding is also enhanced. If 
the component (7) is further added, the electric resistance is reduced, 
and the electrodeposition coating can be advantageously performed without 
coating unevenness. Therefore, excellent rust-prevention on the adhered 
surface of a metal article can be attained. 
Moreover, the structural adhesive of the present invention obtained by 
impregnating, spread-coating or laminating a strand mat, cloth, nonwvoven 
fabric or the like composed of a glass fiber, a glass fiber/organic fiber 
composite, an organic fiber or a carbon fiber with the above-mentioned 
adhesive composition can be sufficiently fixed to adherends such as steel 
plates, especially oil-adhering metals, plastics and fiber-reinforced 
plastic, without any washing or cleaning treatment, and manifests a strong 
bondability by heating and curing. Moreover, this structural adhesive is 
advantageous in that bonding is possible without any cleaning treatment or 
after a simple treatment. 
The structural adhesive of the present invention is generally used as a 
steel plate-reinforcing adhesive, an adhesive for forming a honeycom 
structure of a metal, plastics or paper and an adhesive for bonding same 
materials, such as metals, to each other, or bonding different materials, 
such as a metal and a plastic material, to each other. Accordingly, the 
structural adhesive of the present invention can be widely used in various 
fields for vehicles, ships, household and industrial electric appliances, 
construction materials, engineering construction, ordinary utensils and 
the like.

The present invention will now be described in detail with reference to the 
following examples and comparative examples. Note, in tables given in the 
examples and comparative examples, all of "parts" are by weight. 
The properties of adhesives were determined according to the following 
methods. 
Oil Surface-Fixing Property 
A JIS steel plate which had not been surface-treated was immersed in a 
rust-preventive oil (Metal Guard 831) and was hung vertically for 24 
hours. A sheet-like adhesive sample was interposed between two steel 
plates to lightly compress the adhesive sample in the state where the oil 
was thinly left on the surface, and the oily surface-fixing property of 
the thus-formed test piece was examined. 
Slipping at Heating 
The test piece obtained by interposing and lightly compressing the 
sheet-like adhesive between two metal sheets in the above-mentioned manner 
was vertically hung in an oven maintained at 80.degree. C. for 30 minutes, 
and slipping upon heating was evaluated. 
Bonding Force 
The same test piece as used for evaluation of slipping at heating was 
heated at 215.degree. C. for 30 minutes and the bonding forces (tensile 
shear strength, T-peel strength and flexural strength) were measured 
according to JIS K-6850. 
EXAMPLES 1 THROUGH 14 
Components shown in Table 1 or 2 were used in amounts shown in Table 1 or 
2. Components except an organic peroxide as the component (4) and an 
imidazole or tertiary amino group-containing amino compound as the 
component (5) were mixed together on a mill, and then the components (4) 
and (5) were incorporated into the mixture under cooling. Then, the 
mixture was formed into a sheet having a thickness of 0.6 to 0.8 mm. 
TABLE 1 
__________________________________________________________________________ 
Component Example No. 
No. Composition (parts) 
1 2 3 4 5 6 7 
__________________________________________________________________________ 
(1) Carboxyl group-containing 
100 100 100 100 
NBR (NBR-1072) 
Acrylic rubber (AR-31) 100 100 100 
(2) Epoxy acrylate resin 
(I)*.sup.1 
100 100 90 50 80 100 
(II)*.sup.2 
65 70 60 
(III)*.sup.3 70 100 40 
n-Butyl acrylate 5 10 
Tetrahydrofurfuryl methacrylate 
10 20 
2-Ethylhexyl methacrylate 20 5 
(3) Trimethylol propane 10 10 
trimethacrylate 
1,4-Butanediol acrylate 5 5 
Glycidyl methacrylate 
50 60 50 70 60 40 50 
(6) Mono (2-methacryloyloxy- 
15 15 10 5 5 
ethyl) acid phosphate 
Dimethylaminoethyl 5 3 
methacrylate 
(4) t-Butyl peroxide 
1.8 
t-Butyl perbenzoate 2 2 2 2 
2,2-Di(t-butylperoxy)butane 2 2 
(5) Imidazole 2P4MZ*.sup.10 
2 1.8 1.8 1.8 1.8 
DMP-30*.sup.11 2 2 
Properties 
Oily face-fixing property 
Good 
Good 
Good 
Good 
Good 
Good 
Good 
Slipping upon heating at 80.degree. C. for 30 min. 
No No No No No No No 
Bonding force 
(Tensile shear strength) kg/cm.sup.2 
240 220 200 190 180 200 170 
(T-peel strength) kg/25 mm 
15 12 13 14 13 13 14 
(Flexural strength) kg 
19 17 17 18 17 17 17 
(heated in oven at 215.degree. C. for 30 min.) 
__________________________________________________________________________ 
TABLE 2 
__________________________________________________________________________ 
Component Example No. 
No. Composition (parts) 
8 9 10 11 12 13 14 
__________________________________________________________________________ 
(1) Ethylene/vinyl acetate 
100 
copolymer*.sup.4 
Ethylene/acrylic acid 
100 
copolymer 
Thermoplastic polyurethane*.sup.5 
100 
Chlorosulfonated polyethyl- 
100 
ene*.sup.6 
Chloroprene*.sup.7 100 
Santurated polyester*.sup.8 100 
Nylon*.sup.9 100 
(2) Epoxy acrylate resin*.sup.1 
120 120 120 120 120 120 120 
(3) Glycidyl methacrylate 
50 50 50 50 50 50 50 
(4) t-Butyl perbenzoate 
2 2 2 2 3 2 2 
Zinc oxide 5 5 
(5) Imidazole 2P4MZ*.sup.10 
1.8 1.8 1.8 2 2 1.8 1.8 
Properties 
Oily surface-fixing property 
Good 
Good 
Good 
Good 
Good 
Good 
Good 
Slipping upon heating at 80.degree. C. for 30 min. 
No No No No No No No 
Bonding force 
(Tensile shear strength) kg/cm.sup.2 
180 210 230 170 180 210 240 
(T-peel strength) kg/25 mm 
14 15 17 12 12 13 15 
(Flexural strength) kg 
18 19 19 17 17 17 18 
__________________________________________________________________________ 
Note 
*.sup.1 product formed by adding methacryloyl groups to both ends of 
bisphenol A diglycidyl ether 
*.sup.2 Product formed by adding methacryloyl groups to both ends of 
Epikote 1001 
*.sup.3 product formed by adding methacryloyl groups to both ends of 
Epikote 834 
*.sup.4 vinyl acetate content of 33% by weight 
*.sup.5 ester type thermoplastic polyurethane (marketed under tradename o 
"Pandex T5205" by Dainippon Ink and Chemicals, Inc.) 
*.sup.6 Hypalon 40 supplied by Du Pont Co. 
*.sup.7 W type 
*.sup.8 Vylon supplied by Toyobo Co. 
*.sup.9 copolymer of nylon 6, nylon 66 and nylon 6, 10 
*.sup.10 2phenyl-4-methylimidazole 
*.sup.11 2,4,6tris(dimethylaminomethyl)phenol 
As seen from the results shown in Tables 1 and 2, each of the adhesive 
compositions of Examples 1 through 14 comprising the components (1) 
through (5) and optionally together with the component (6), has a high 
bondability and a good oily surface-fixing property and does not cause 
slipping of adherents upon heating. 
EXAMPLE 15 
In a mill were mixed 100 parts of a carboxyl group-containing 
acrylonitrile/butadiene copolymer (Nipol 1072 supplied by Nippon Zeon 
Co.), as the component (1), 100 parts of a bisphenol-based epoxy acrylate 
resin and 65 parts by weight of an epoxy acrylate formed by adding 
emthacrylic acid to the ends of a high-molecular-weight bisphenol A type 
epoxy resin (Epikote 1001 supplied by Shell Chemical Co.) as the component 
(2), 50 parts by weight of glycidyl methacrylate as the component (3) and 
15 parts by weight of mono(2-acryloyloxyethyl) acid phosphate as the 
component (6). Thereafter, 2 parts by weight of Imidazole 2P4MHZ as the 
component (5) and 1.8 parts by weight of t-butyl peroxide as the component 
(4) were added to the resulting mixture while cooling to form a 
composition. This composition was coated on a glass chopped strand mat 
having a width of 310 mm and a unit weight of 300 g/m.sup.2 by a sheeting 
machine. The necessary thickness was obtained by piling the formed sheets 
according to the amount of the composition coated and the unit weight of 
the strand mat used. Thus, a sheet-like structural adhesive having a 
thickness of 0.8 mm was prepared. Slipping upon heating was not observed 
in case of the thus-obtained sheet-like structural adhesive, and the 
excellent bonding force was such that the tensile shear strength was 220 
kg/cm.sup.2 and the peel strength (90.degree. peel) was 22 kg/25 mm of the 
width. 
EXAMPLES 16 THROUGH 25 
The tensile shear strength of the sheet-like structural adhesive prepared 
in Example 15 was measured by using various oils shown in Table 3. The 
obtained results, together with the value obtained in Example 15, are 
shown in Table 3. 
TABLE 3 
__________________________________________________________________________ 
Example Bonding force (tensile shear 
No. Oil strength) (kg) 
Note 
__________________________________________________________________________ 
15 Metal guard 831 
190 Metal working oil 
16 Vacuoline 200 Lubricating oil for sliding faces 
supplied by Mobil Petroleum 
17 DTE 24 230 Lubricating oil for rotary parts 
18 DTE 26 210 " 
19 DTE B3 185 " 
20 Molub gear 634 
200 Lubricating oil for gears 
21 Molub gear +140 
180 " 
22 Molub gear 300S 
180 " 
23 Sultran B-3 
210 Metal working oil for ordinary cutting 
supplied by Mobil Petroleum 
24 Normal oil 250 Metal working oil for finishing 
25 Toshiba silicone TSH 
180 General purpose silicone oil 
__________________________________________________________________________ 
As apparent from the data shown in Table 3, when the adhesive of the 
present invention is used, a preferred bonding force is obtained 
irrespective of the kind of the oil on a steel plate. 
EXAMPLES 26 THROUGH 32 
Sheet-like structural adhesives having a thickness shown in Table 5 were 
obtained by coating compositions A through F shown in Table 4 on a chopped 
strand mat, a surface mat, a glass cloth, a nonwoven fabric or a victoria 
lawn as shown in Table 5. The properties of these structural adhesives are 
shown in Table 5. 
TABLE 4 
__________________________________________________________________________ 
Component 
No. Composition (parts) A B C D E F 
__________________________________________________________________________ 
(1) NBR*.sup.1 100 100 
Acrylic rubber AR31 100 
Ethylene/acrylate copolymer 
100 
Saturated polyester*.sup.2 100 
Nylon 100 
(2) Epoxy acrylate resin I*.sup.3 
100 
120 
100 
100 
100 
100 
Epoxy acrylate resin II*.sup.4 
40 30 50 60 50 50 
(3) Glycidyl methacrylate 
60 60 60 60 60 60 
(6) Mono(2-acryloyloxyethyl) acid phosphate 
10 15 15 15 15 15 
(4) t-Butyl perbenzoate 2.5 
3.0 
3.0 
3.0 
2.0 
2.0 
(5) DMP-30*.sup.5 2.0 
2.0 
2.0 
2.0 
2.0 
2.0 
__________________________________________________________________________ 
Note 
*.sup.1 Nipol 1072 supplied by Nippon Zeon Co. 
*.sup.2 marketed under the tradename of 
*.sup.3 bisphenol Abased epoxy acrylate resin 
*.sup.4 epoxy acrylate resin formed by adding methacrylic acid to the end 
of epoxy resin of bisphenol A type having high molecular weight 
*.sup.5 2,4,6tris(dimethylaminomethyl)phenol 
TABLE 5 
__________________________________________________________________________ 
Example No. 26 27 28 29 30 31 32 
Composition A A B C D E F 
__________________________________________________________________________ 
Chopped strand mat*.sup.5 
o o 
Surface mat*.sup.6 o 
Glass cloth*.sup.7 o 
Nonwoven fabric*.sup.8 o 
Victoria lawn*.sup.9 o 
Victoria lawn*.sup.10 o 
Properties 
Oily surface-fixing property 
Good 
Good 
Good 
Good 
Good 
Good 
Good 
Slipping upon heating at 80.degree. C. 
No No No No No No No 
for 30 min. 
Bonding force 
Tensile shear strength 
180 200 190 170 160 150 170 
(kg/cm.sup.2) 
T-peel strength (kg/25 mm) 
25 24 26 22 18 18 19 
Flexural strength (kg) 
18 18 19 18 17 17 17 
Thickness of adhesive (mm) 
1.0 1.0 1.0 0.8 0.8 0.7 1.0 
__________________________________________________________________________ 
Note 
*.sup.5 "CM 300" supplied by Asahi Fiber Glass Co., basis weight = 300 
g/m.sup.2 
*.sup.6 "SM 3605" supplied by Asahi Fiber Glass Co., thickness = 0.64 mm, 
basis weight = 100 g/m.sup.2 
*.sup.7 "MG 130" supplied by Asahi Fiber Glass Co., thickness = 0.13 mm, 
density 19/19 (filaments/25 mm) 
*.sup.8 polyester, "B50410" supplied by Toray Ind. Inc., thickness = 0.20 
mm, basis weight = 40 g/m.sup.2 
*.sup.9 polyester, "T100" supplied by Teijin Ltd. 
*.sup.10 vinylon #510 supplied by Unitika Ltd., LSF = 30 .times. 30, 
density = 15 .times. 15 
EXAMPLE 33 AND COMATIVE EXAMPLE 1 
Materials other than steel plates were bonded by the adhesive used in 
Example 15, and the bonding force (tensile shear strength) was measured to 
obtain results shown in Table 6. Stainless steel, brass and aluminum were 
used as the adherents. For comparison, a commercially available epoxy type 
adhesive was used and the bonding force was measured. 
TABLE 6 
______________________________________ 
Adherents Example 33 
Comparative Example 1* 
______________________________________ 
Stainless steel plates 
170 kg/cm.sup.2 
50 kg/cm.sup.2 
Brass plates 80 kg/cm.sup.2 
20 kg/cm.sup.2 
Aluminum plates 
100 kg/cm.sup.2 
30 kg/cm.sup.2 
______________________________________ 
Note 
*commercially available epoxy type adhesive 
From the results shown in Table 6, it is seen that the adhesive of the 
present invention shows an excellent bonding strength even in the case of 
a special material or part where bonding is impossible by ordinary 
adhesives unless a special preliminary treatment is carried out. 
EXAMPLE 34 
Sheets of FRP (epoxy resin/glass fiber) having a length of 100 mm, a width 
of 25 mm and a thickness of 2 mm were bonded together without any 
particular preliminary treatment by using an adhesive composition which 
was the same as the adhesive composition of Example 15 except that benzoyl 
peroxide was added instead of t-butyl perbenzoate. Heating was conducted 
at 60.degree. C. for 40 minutes because FRP became soft at a higher 
temperature, and the tensile shear strength and flexural strength were 
measured. The tensile shear strength was higher than 150 kg/cm.sup.2 and 
the state of the material fracture was substantially brought about. The 
flexural strength was higher than 18 kg. No peeling was caused and FRP 
whitened. 
EXAMPLE 35 
In a mill were mixed 100 parts by weight of an acrylic rubber (Nipol AR-31 
supplied by Nippon Zeon Co.) as the component (1), 100 parts by weight of 
a bisphenol-based epoxy acrylate resin and 60 parts by weight of an epoxy 
acrylate formed by adding methacrylic acid to the ends of a 
high-molecular-weight bisphenol A type epoxy resin (Epikote 1001 supplied 
by Shell Chemical Co.) as the component (2), 50 parts by weight of 
glycidyl methacrylate as the component (3) and 30 parts by weight of 
tetrahydrofurfuryl acrylate as the optional component. Then, 2 parts by 
weight of Imidazole 2P4MZ (2-phenyl-4-methylimidazole) as the component 
(5) and 1.8 parts by weight of t-butyl peroxide as the component (4) were 
added to the resulting mixture under cooling to form an adhesive 
composition. The adhesive composition was coated n a chopped strand mat 
having a width of 310 mm and a unit weight of 300 g/m.sup.2 by a sheeting 
machine. The necessary thickness was obtained by piling the coated sheets 
according to the amount of the adhesive composition coated and the unit 
weight of the strand mat. Thus, a sheet-like structural adhesive having a 
thickness of 1.2 mm was obtained. 
This structural adhesive showed tensile shear strength of 190 kg/cm.sup.2 
and a T-peel strength of 21 kg/25 mm of the width. 
EXAMPLES 36 THROUGH 44 
Components shown in Table 7, except t-butyl perbenzoate, were kneaded by a 
pressure kneader, and t-butyl perbenzoate was incorporated into the 
mixture in a cooling mill so that heat was not generated, whereby an 
adhesive composition was prepared. 
The thus-prepared adhesive composition was coated on a carbon fiber strand 
mat having a width of 310 mm and a unit weight of 300 g/m.sup.2 by a 
sheeting machine. The necessary thickness was obtained by piling the 
coated sheets according to the amount of the composition coated and the 
unit weight of the strand mat used. Thus, sheet-like electrically 
conductive adhesives (Examples 36 through 44) having a thickness of 1 mm 
were prepared. 
With respect to each of these sheet-like adhesives, slipping upon heating 
was not caused. The bonding force and the volume resistivity (.OMEGA.-cm 
at 23.degree. C.) of each adhesive are shown in Table 7. 
When the sheet-like electrically conductive adhesive was subjected to 
electrodeposition coating before heating, the steel plate surface and the 
interface between the steel plate and the adhesive were uniformly coated. 
At the salt spray test, generation and growth of rust were very slow. 
TABLE 7 
__________________________________________________________________________ 
Component Example No. 
No. Composition (parts) 
36 37 38 39 40 41 42 43 44 
__________________________________________________________________________ 
(1) NBR*.sup.1 100 
100 
100 
100 
100 
100 
100 
100 
100 
(2) Epoxy acrylate resin I*.sup.2 
100 
100 
100 
100 
100 
100 
100 
100 
100 
Epoxy acrylate resin II*.sup.3 
65 65 65 65 65 65 65 65 65 
(3) Glycidyl methacrylate 
50 50 50 50 50 50 50 50 50 
(6) Ketjenblack*.sup.4 
30 
Acetylene black 40 30 
Lamp. black 40 
Electroconductive carbon A*.sup.5 
40 30 
Electroconductive carbon B*.sup.6 
40 
Electroconductive carbon C*.sup.7 40 
Carbon black HAF (N330)*.sup.8 40 
(4) t-Butyl perbenzoate 
1.8 
1.8 
1.8 
1.8 
1.8 
1.8 
1.8 
1.8 
1.8 
(5) Imidazole 2P4MZ*.sup.9 
2 2 2 2 2 2 2 2 2 
Properties 
Volume resistivity (.OMEGA.-cm, 23.degree. C.) 
2.4 
6.8 
7.7 
1.0 
9.3 
3.4 
4.7 
7.2 
3.3 
.times. 
.times. 
.times. 
.times. 
.times. 
.times. 
.times. 
.times. 
.times. 
10.sup.5 
10.sup.4 
10.sup.4 
10.sup.5 
10.sup.4 
10.sup.5 
10.sup.5 
10.sup.5 
10.sup.5 
Bonding force 
Tensile shear strength (kg/cm.sup.2) 
190 
177 
182 
173 
190 
196 
187 
-- -- 
T-peel strength 20 18 17 17 17 20 20 -- -- 
(kg/25 mm of width) 
__________________________________________________________________________ 
Note 
*.sup.1 Nipol 1072 supplied by Nippon Zeon Co. 
*.sup.2 bisphenol Abased epoxy acrylate resin 
*.sup.3 epoxy acrylate resin obtained by adding methacrylic acid to the 
ends of highmolecular-weight bisphenol A type epoxy resin 
*.sup.4 Ketjenblack EC supplied by LionAkzo Co. 
*.sup.5 Vulcan XC72 supplied by Cabot Corp., N.sub.2 surface area = 254 
m.sup.2 /g, DBP oil absorption = 178 cc/100 g, bulk specific gravity = 26 
kg/m.sup.3 
*.sup.6 Black Pearl 700 supplied by Cabot Corp., N.sub.2 surface area = 
200 m.sup.2 /g, DBP oil absorption = 115 cc/100 g, bulk specific gravity 
= 336 kg/m.sup.3 
*.sup.7 Vulcan C supplied by Cabot Corp., N.sub.2 surface area = 125 
m.sup.2 /g, DBP oil absorption = 100 cc/100 g, bulk specific gravity = 37 
kg/m.sup.3 
*.sup.8 N.sub.2 surface area = 83 m.sup.2 /g, DBP oil absorption = 102 
cc/100 g, bulk specific gravity = 375 kg/m.sup.3 
*.sup.9 2phenyl-4-methylimidazole 
As is seen from the results shown in Table 7, each of the adhesives of 
Examples 36 through 44 according to the present invention has a good 
bonding force even if an oil adheres to a steel surface. The volume 
resistivity of each of the adhesives of Examples 36 through 43 is lower 
than that of the adhesive of Example 44 comprising Carbon Black HAF. 
EXAMPLES 45 THROUGH 47 
Adhesive compositions shown in Table 8, which were prepared in the same 
manner as in Example 36, were coated on carbon cloth, glass mat and glass 
sheet shown in Table 8 to obtain sheet-like electrically conductive 
adhesives having a thickness of 1.1 mm. With respect to each of the 
thus-prepared electrically conductive adhesives, the volume resistivity 
and bonding force were measured, and the electrodeposition property at the 
electrodeposition coating step was evaluated. The obtained results are 
shown in Table 8. 
TABLE 8 
______________________________________ 
Com- 
ponent Example No. 
No. Composition (parts) 
45 46 47 
______________________________________ 
(1) NBR*.sup.1 100 100 100 
(2) Epoxy acrylate resin I*.sup.2 
100 100 100 
Epoxy acrylate resin II*.sup. 3 
65 65 65 
(3) Glycidyl methacrylate 
50 50 50 
(6) Mono(2-acryloyloxyethyl) acid 
15 15 15 
phosphate 
(7) Ketjenblack*.sup.4 15 20 
Graphite 20 
Ni powder 100 
Al powder 100 80 
Cut carbon fiber 10 
(4) t-Butyl perbenzoate 
1.8 
(5) Imidazole 2P4MZ 2 
Carbon cloth 1 sheet 
Glass mat 1 sheet 
Glass cloth 1 sheet 
Properties 
Volume resistivity (.OMEGA.-cm, 23.degree. C.) 
4.1 .times. 
1.7 .times. 
2.2 .times. 
10.sup.5 
10.sup.5 
10.sup.5 
Bonding force 
Tensile shear strength (kg/cm.sup.2) 
170 160 180 
Electrodeposition property 
Good Good Good 
______________________________________ 
Note 
*.sup.1 same as in Table 7 
*.sup.2 same as in Table 7 
*.sup.3 same as in Table 7 
*.sup.4 same as in Table 7 
From the results shown in Table 8, it is seen that each of the adhesives of 
Examples 45 through 47 has a low volume resistivity and a high bonding 
force (tensile shear strength) and has a good electrodeposition property 
with no coating unevenness. 
EXAMPLES 48 THROUGH 52 
Compositions shown in Table 9, which were prepared in the same manner as in 
Example 36, were sheeted on carbon cloth, glass mat and glass cloth shown 
in Table 9 to form sheet-like electroconductive adhesives having a 
thickness of 1.1 mm. With respect to each of these electroconductive 
adhesives, the volume resistivity and the bonding force (tensile shear 
strength) were measured, and the electrodeposition property at the 
electrodeposition coating was evaluated. The obtained results are shown in 
Table 9. 
TABLE 9 
__________________________________________________________________________ 
Component Example No. 
No. Composition (parts) 
48 49 50 51 52 
__________________________________________________________________________ 
(1) Acrylic rubber*.sup.9 
100 100 100 100 100 
NBR*.sup.10 30 30 30 30 30 
(2) Epoxy acrylate resin I*.sup.2 
80 80 80 80 80 
Epoxy acrylate resin II*.sup.3 
80 80 80 80 80 
(3) Glycidyl methacrylate 
40 40 40 40 40 
(6) Mono(2-acryloyloxyethyl) acid 
10 10 10 10 10 
phosphate 
(7) Ketjenblack*.sup.4 20 10 30 
Graphite 20 30 
Ni powder 80 
Al powder 120 100 100 120 
Cut carbon fiber 10 
(4) t-Butyl perbenzoate 
1.5 1.5 1.5 1.5 1.5 
(5) Imidazole C17Z*.sup.11 
2.5 2.5 2.5 2.5 2.5 
Carbon cloth 1 sheet 
1 sheet 1 sheet 
Glass mat 1 sheet 1 sheet 
1 sheet 
Glass cloth 1 sheet 
Properties 
Volume resistivity (.OMEGA.-cm, 23.degree. C.) 
2.3 .times. 10.sup.5 
8.2 .times. 10.sup.5 
2.6 .times. 10.sup.5 
7.5 .times. 10.sup.5 
3.5 .times. 10.sup.5 
Bonding force 
Tensile shear strength (kg/cm.sup.2) 
160 150 165 174 155 
Electrodeposition property 
Good Good Good Good Good 
__________________________________________________________________________ 
Note 
*.sup.2 same as in Table 7 
*.sup.3 same as in Table 7 
*.sup.4 same as in Table 7 
*.sup.5 Nipol AR31 supplied by Nippon Zeon Co. 
*.sup.10 Hycar CTBN 1300X13 supplied by B. F. Goodrich Co. 
*.sup.11 2heptadecylimidazole 
From the results shown in Table 9, it is seen that each of the 
electroconductive adhesives of Examples 48 through 52 has a low volume 
resistivity and a high bonding force (tensile shear strength) and has a 
good electrodeposition property with no coating unevenness. When the 
T-peel strength of the electroconductive adhesive of Example 48 was 
measured, it was found that the T-peel strength was 18 kg/25 mm of the 
width. Thus, it has been confirmed that the electroconductive adhesive of 
the present invention is excellent in both the tear shear strength and the 
peel strength. 
EXAMPLE 53 
In a pressure kneader, 100 parts by weight of an acrylonitrile/butadiene 
copolymer (Nipol 1072 supplied by Nippon Zeon Co.) as the component (1), 
100 parts by weight of an epoxy acrylate resin A having terminal 
methacrylic groups, obtained by reacting Epikote 828 (supplied by Shell 
Chemical) with methacrylic anhydride, and 65 parts by weight of an epoxy 
acrylate resin having terminal methacrylic groups, obtained by reacting 
Epikote 1004 (supplied by Shell Chemical) with methacrylic acid, as the 
component (2), 30 parts by weight of tetrahydrofurfuryl acrylate as the 
component (3), 1.8 parts by weight of imidazole C17Z 
(2-heptadecylimidazole) as the component (5) and 35 parts by weight of 
Ketene Black (supplied by Akuzor Co.) as the component (7) were mixed 
together. Then, 1.8 parts by weight of t-butyl perbenzoate as the 
component (4) was added to the resulting mixture on a cooling mill so that 
heat was not generated, whereby an adhesive composition was obtained. The 
adhesive composition was coated on a carbon fiber strand mat having a 
width of 310 mm and a unit weight of 300 g/m.sup.2 to obtain an 
electrically conductive adhesive having a thickness of 1 mm. The volume 
resistivity of this electrically conductive adhesive was as low as 
2.2.times.10.sup.5 .OMEGA.-cm. It was found that this electrically 
conductive adhesive showed a tensile shear strength of 187 kg/cm.sup.2 and 
a T-peel strength of 20 kg/25 mm of the width.