Adhesive tape for preventing implosion and removing electrostatic charge

A circuit for removing electrostatic charges from the surface of a cathode ray tube is formed by adding electrically conductive particles to an adhesive used to prevent an implosion of the tube and located between a metal clamping band and the surface of the tube. The electrically conductive particles have a particular particle size distribution and are dispersed in a particular amount.

BACKGROUND OF THE INVENTION 
Field of the Invention 
The present invention relates to an adhesive tape used together with a 
clamping metal band to prevent an implosion of a cathode ray tube and to 
remove an electrostatic charge from the cathode ray tube. The present 
invention also relates to a process for reinforcing a cathode ray tube 
with the adhesive tape and the clamping metal band against an implosion 
thereof and forming a circuit of the above adhesive tape for removing an 
electrostatic charge from the cathode ray tube. 
Description of the Related Art 
A cathode ray tube (hereinafter CRT) or a Braun tube used for television 
equipment or display is applied with a very high electrical voltage for 
forming an image, and this causes a generation and accumulation of 
electrostatic charges at a peripheral portion of the CRT. The 
electrostatic charges not only attract dust, etc., but also are dangerous 
to viewers if the CRT is touched by hand. Further, accumulated 
electrostatic charges may degrade the quality of the image and cause 
interference of an image. 
Various attempts have been made to try to remove the electrostatic charges, 
due to the disadvantages thereof described above, and in general, a 
graphite or electrically conductive coating is applied to the periphery of 
the CRT by which electrostatical charges are collected and grounded 
through a clamping band and to an earth circuit arranged in a cabinet 
etc., since restructuring of the CRT or television equipment, etc., is 
limited. 
The clamping band is used to prevent an implosion of the CRT, in which a 
high vacuum is established, due to an external impact thereon particularly 
from the front side, and is usually made of a metal, or a high tension 
material. To effectively transmit the clamping pressure of the clamping 
band, to the CRT, and to prevent a direct contact of the clamping band 
with a glass surface of the CRT, which may cause defects such as 
scratching of the glass surface, an adhesive tape composed of a polymer 
and glass cloth which is highly insulative, as disclosed in Japanese 
Examined Patent Publication No. 63-24291, must be adhered between the 
glass and the clamping band, and as a result, the formation of a circuit 
for the removal of electrostatic charges mentioned above must be effected 
by a means different from the above anti-implosion means. 
Other means for removing of electrostatic charges include adhering 
single-sided or double-sided electrically conductive adhesive tapes 
containing an electrically conductive substrate of copper or aluminum foil 
or cloth and electrically conductive fine powders of copper, etc., in an 
adhesive, which have a resistance of several ohms under a pressure of 
several tens of kg/cm.sup.2, around only four corners of a CRT, so that 
the clamping band and the glass are electrically connected via the 
electrically conductive adhesive tapes. This method, however, is not 
reliable, since the effectiveness thereof depends on the skill of the 
maker, and this method sometimes results in a complete peeling off of the 
electrically conductive tapes whereby the electrostatical charge removal 
circuit becomes in operable, or causes short circuits and serious failures 
in the cabinet due to an adhesion thereof of the peeled off electrically 
conductive tapes. Furthermore, this requires great care at the production 
line, and thus is disadvantageous from the viewpoint of a high 
productivity. 
Japanese Unexamined Patent Publication (Kokai) No. 63-43246 published on 
Feb. 24, 1988, proposed a method in which an electrically conductive 
adhesive tape as mentioned above was placed between a tension band and a 
glass surface of a CRT. This method, however, does not consider the effect 
of implosion prevention by the tension band, particularly the necessity of 
adhesion of the band to the CRT and the electrically conductive tape 
causes problems similar to those described above. Accordingly, this 
proposal does not provide a practical method of preventing an implosion of 
and a removal of electrostatical charges from the CRT. 
SUMMARY OF THE INVENTION 
The main object of the present invention is to solve the above problems and 
to provide a practical means for preventing an implosion of and removing 
electrostatic charges from a CRT. 
The above and other objects, features and advantages of the present 
invention are obtained by providing an adhesive tape for preventing an 
implosion of a CRT, the tape comprising a layer of an adhesive, a flexible 
substrate embedded in the adhesion layer and electrically conductive 
particles dispersed in the adhesive layer, the electrically conducting 
particles having a particle size of from 0.1 .mu.m to 300 .mu.m and a mode 
particle size of from 25 .mu.m to 300 .mu.m. The electrically conductive 
particles are contained in a reduced dispersion amount of 1 to 10.sup.5 
cm.sup.-2, this reduced dispersion amount being represented by the 
following formula: 
##EQU1## 
where D.sub.r stands for the reduced dispersion amount (cm.sup.-2), W 
stands for a weight of electrically conductive particles used per unit 
area (g/m.sup.2), V.sub.m stands for a volume of an electrically 
conductive particle at the mode (cm.sup.3), and .rho. stands for a density 
of the electrically conductive particles (g/cm.sup.3). The adhesive tape 
has an electrical resistance before use between the two major surfaces 
thereof of more than 1 M.OMEGA.. 
This adhesive tape allows the use of a clamping band and an adhesive tape 
used with the clamping band for preventing an implosion of a CRT and 
removing electrostatic charges, by the same steps as used for a 
conventional clamping process. 
There is also provided a process for reinforcing a CRT against an implosion 
and for removing electrostatic charges with a clamping band and an 
adhesive tape, this process comprising the steps of: preparing a CRT 
having a maximum peripheral portion and covered with a transparent 
electrically conductive film; applying an adhesive as described above 
completely or partly on or near the maximum peripheral portion of the CRT; 
clamping the CRT with a metal clamping band around the maximum peripheral 
portion of the CRT and on top of the adhesive tape, by heating the metal 
clamping band to a temperature of not less than 120.degree. C. and 
arranging the metal clamping band around the adhesive tape, and then 
allowing the metal clamping band to cool so that the maximum peripheral 
portion of the tube with the adhesive tape is clamped by the metal 
clamping band, wherein the adhesive tape after the clamping thereof has an 
electrical resistance between the two major surfaces thereof of less than 
1 M.OMEGA. so that an electrical circuit composed of the transparent 
electrically conductive film, the metal clamping band, and the adhesive 
tape, which is to be connected to the ground, is formed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The clamping band is designed to generate a high clamping force by using a 
high tension metal band and heating and cooling i.e., expanding and 
shrinking same, to prevent an implosion of a CRT in a vacuum state. 
Although the clamping force depends on the design of the CRT or the 
structure of the clamping band, this force is usually more than 30 
kg/cm.sup.2 around the four corners of and 1 to 10 kg/cm.sup.2 at the flat 
peripheral portions, of the CRT. A higher pressure may be applied or 
generated at protruding portions or steps, such as mold match lines. An 
adhesive layer is inserted between the clamping band and the CRT, by 
winding the adhesive tape around the CRT and arranging a clamping band on 
top of the adhesive tape. An effective adhesive tape comprises an adhesive 
layer and a substrate contained in the adhesive layer, optionally with a 
filler. The inventors et al found that the adhesive tape must not be 
broken when clamped under a high pressure, as mentioned above, and an 
effective adhesive layer must be present between the clamping band and the 
CRT, to prevent an implosion of the CRT by the clamping band. Accordingly, 
the adhesive tape must have a special structure. 
When the adhesive tape is subjected to the clamping pressure, the adhesive, 
which is an organic component, is fused or softened, and thus made 
flowable, by the heat of the clamping band. When a substrate is composed 
of a glass cloth or the like, the adhesive tape is finally held by the 
substrate and a cohesion of the adhesive. In this case, the limitation of 
the flowability of the adhesive is defined by a thickness of the glass 
cloth or a diameter of glass fibers around the corners of the CRT, whereat 
a particularly high pressure is applied. When the substrate is a polyester 
film or the like, the adhesive tape is finally held by a cohesion of the 
film and adhesive and the limitation of the flowability of the adhesive is 
defined by a particle size of a filler or a slip-preventing component 
contained in the adhesion layer. The inventors carefully studied the above 
phenomena, and thus added an inorganic electrically-conductive particles 
to the adhesive layer, whereby the electrical resistance between the 
clamping band and the glass CRT is reduced to a level capable of removing 
electrostatic charges, i.e., less than 1 M.OMEGA., preferably less than 
10.sup.4 .OMEGA., more preferably less then 10 .OMEGA., when clamped. A 
conventional adhesive tape used with a clamping band has an inherent 
volume electric resistance of usually more than 10.sup.9 .OMEGA.-cm, 
typically more than 10.sup.13 .OMEGA.-cm, which is a heavy insulator. The 
adhesive tape according to the present invention also must have a high 
electric resistance before clamping, i.e., more than 1 M.OMEGA., 
preferably more than 10.sup.3 M.OMEGA., between the two major surfaces of 
the adhesive tape. This high electric resistance of the adhesive is 
necessary to prevent short circuits in television equipment, etc., caused 
by a peeling off and adhesion of a portion of the adhesive when clamped. 
At the same time, the adhesive tape according to the present invention 
must have an electric resistance of less than 1 M.OMEGA., preferably less 
than 10.sup.4 .OMEGA., more preferably less than 10 .OMEGA., between the 
two major surfaces of the adhesive tape, after clamped under a pressure 
of, for example, 10 to 30 kgf/cm.sup.2. Furthermore, the adhesive tape 
according to the present invention must retain the ability to prevent an 
implosion of the CRT when clamped with a clamping band. 
Note that conventional electrically conductive tapes have an electrical 
conductivity of less than several hundred milli ohms before use or after 
used without pressing, and therefore are not suitable for the purposes of 
the present invention. 
The above requirements of the present invention are met by adding 
electrically conductive particles having a specific particle size to an 
adhesive layer having a substrate therein, in a specific dispersion 
amount. The electrically conductive particles preferably have a particle 
size of 0.1 .mu.m to 300 .mu.m and a mode particle size of 25 .mu.m to 300 
.mu.m, are contained in a reduced dispersion amount of 1 to 10.sup.5 
cm.sup.-2. This reduced dispersion amount is represented by the following 
formula: 
##EQU2## 
where D.sub.r stands for the reduced dispersion amount (cm.sup.-2), W 
stands for a weight of electrically conductive particles used per unit 
area (g/m.sup.2), V.sub.m stands for a volume of an electrically 
conductive particle at the mode (cm.sup.3), and .rho. stands for a density 
of the electrically conductive particles (g/cm.sup.3). The term "mode" is 
used to indicate the particle size present in the maximum amount among the 
electrically conductive particles. Preferably, the adhesive tape according 
to the present invention includes at least one electrically insulative 
organic layer having an electric resistance of more than 10.sup.9 
.OMEGA.-cm, to ensure the high electric resistance of the tape before use 
or when peeled off. 
By applying the above adhesive tape completely or partly around or near a 
maximum periphery portion of a CRT, followed by clamping, the heat and 
pressure of a clamping band cause a flow of flowable components in the 
adhesive tape, and the electrically conductive particles are densified 
directly under the clamping band since the flowability of the particles is 
reduced due to contact with or a close approach to each other, the 
clamping band, and the surface of the CRT, whereby the electric resistance 
of the adhesive tape is reduce to less than 1 M.OMEGA., preferably less 
than 10.sup.4 .OMEGA., more preferably less than 10 .OMEGA., between the 
two major surfaces thereof. This is the basis of the present invention. 
The present invention is described with reference to the drawings. 
FIG. 1 illustrates a CRT provided with an implosion prevention means. In 
the figure, 1 denotes a clamping band, 2 an adhesive tape according to the 
present invention, 3 a CRT, 4 a transparent electrically conductive film, 
5 a lug, 6 a cabinet, and 7 a wire to the ground. 
FIGS. 2 and 3 illustrate preferable adhesive tapes according to the present 
invention, before clamping. In FIG. 2, 1 denotes a clamping band, 2 an 
adhesive tape, 3 a CRT, 11 a substrate of a fabric, 12 a first adhesive 
layer, 13 a second adhesive layer, and 14 electrically conductive 
particles. This structure of the adhesive tape comprising the first and 
second adhesive layers 12 and 13 and the fabric substrate 11 therebetween 
provides an effective implosion prevention effect in cooperation with the 
clamping band, because the substrate 11 keeps the tape when clamped with 
the clamping metal band 1 and the adhesive layers 12 and 13 remain and are 
adhered to the clamping band 1 and the CRT 3 respectively. 
The fabric substrate 11 may be of, for example, glass cloth, rayon 
(polyester) cloth, cotton cloth, etc. or a union or mixed cloth thereof. 
The thickness of the fabric is from 50 .mu.m to 800 .mu.m, preferably from 
100 .mu.m to 400 .mu.m depending on the design of the CRT and the shape of 
the clamping band. If the thickness of the fabric is less than 50 .mu.m, 
the substrate 11 is cut when clamped and the implosion prevention effect 
is lost. If the thickness of the fabric is more than 800 .mu.m, large 
electrically conductive particles must be used to obtain a sufficient 
electrical conductivety, which may damage the surface of the CRT, or a 
large amount of small electrically conductive particles must be used, 
which is impractical from the veiwpoint of cost. 
The first adhesive layer 12 is a pressure sensitive adhesive which 
effectively causes an initial adhesion to the CRT 3. The pressure 
sensitive adhesives are known, and typically, are a synthetic resin system 
containing acrylate copolymer as the main component or a natural rubber 
system having a tackfier resin, etc., incorporated thereon. The first 
adhesive layer 12 is preferably applied in an amount or thickness of 25 
g/m.sup.2 to 500 g/m.sup.2, more preferably 50 g/m.sup.2 to 200 g/m.sup.2. 
If this amount or thickness is less than 25 g/m.sup.2, the first adhesive 
layer 12 is streaky when applied and has a poor initial adhesion to the 
glass. If the amount or thickness is more than 500 g/m.sup.2, a large 
amount of the adhesive is forced out when the tape is clamped, resulting 
in a poor aesthetic appearance, and the adhesive has an excess flowability 
which can allow movement of the tape after cooling. 
The second adhesive layer 13 is preferably an electrically insulative 
organic adhesive having an inherent electric resistance of more than 
10.sup.9 .OMEGA.-cm. If the resistance is less than 10.sup.9 .OMEGA.-cm, 
the adhesive tape easily becomes electrically conductive. Accordingly, the 
electrically conductive particles 14 should not preferably be incorporated 
in this second adhesive layer 13. This high insulation of the second 
adhesive layer 13 ensures that the adhesive tape 2 has a sufficient 
electric resistance even if the electrically conductive particles 14 are 
incorporated in the adhesive tape 2, although the specifically limited 
amount of the electrically conductive particles used according to the 
present invention provides the adhesive tape 2 with the necessary 
insulation before clamped. The second adhesive layer 13 is preferably a 
thermoset or themoplastic resin type adhesive, i,e., not a pressure 
sensitive adhesive. This is because, if the second adhesive layer 13 is a 
pressure sensitive type, dust may be deposited and adhered on exposed 
areas of the second adhesive layer 13 after clamped with the clamping band 
1, which leads to a poor aesthetic appearance of the CRT. The thermoset 
resin type adhesives are known and include, for example, epoxy or 
polyester resins intermediately cured by a cross-linking agent. The 
thermoplastic resin type adhesives are also known and include, for 
example, polythylene or ethylene-vinyl acetate copolymer. The second 
adhesive type 13 is preferably applied in an amount or thickness of 10 
g/m.sup.2. If this amount or thickness is less than 10 g/m.sup.2, the 
insulation effect is decreased, and an amount or thickness of more than 
200 g/m.sup.2 may disadvantageously prevent an increase of the electric 
resistance of the tape 2 after clamping, or disadvantageously allow 
movement of the tape after clamping and cooling. 
As mentioned above, the electrically conductive particles 14 are preferably 
incorporated only in the first adhesive layer 12. The amount of 
electrically conductive particles 14 is defined as stated above according 
to the present invention. This amount allows a high electric resistance 
before clamping and a required electrical conductivity after clamping. 
The electrically conductive particles 14 may be metal powders selected from 
powders of iron, copper, aluminum, nickel, silver and alloys thereof, and 
preferably have a particle size of 0.1 .mu.m to 300 .mu.m, more preferably 
25 .mu.m to 300 .mu.m, and a mode particle size of 25 .mu.m to 300 .mu.m. 
If the mode particle size is less than 25 .mu.m, a large amount of the 
particles 14 must be incorporated to attain the desired effect, which 
disadvantageously increases the cost and degrades the adhesive 
characteristics. If the mode particle size is more than 300 .mu.m, larger 
particles receive a local clamping force from the clamping band, whereby 
the surface of the cathode ray tube may be damaged or the implosion 
prevention effect reduced, or the adhesive tape will have a lower electric 
resistance before use, which may cause short circuits and faults due to 
accidental contact of the particles separated from the tape with circuits 
of the body. 
The electrically conductive particles 14 are preferably contained in the 
adhesive tape in a reduced dispersion amount, as defined above, of 1 
cm.sup.-2 to 10.sup.5 cm.sup.-2. The reduced dispersion amount must be 
more than 1 cm.sup.-2 to obtain the desired effect, but an amount of more 
than 10.sup.5 cm.sup.-2 results in increased costs and decreased 
characteristics. Preferably the reduced dispersion amount is 1 cm.sup.-2 
to 5.times.10.sup.3 cm.sup.-2, more preferably 1 cm.sup.-2 to 
2.times.10.sup.3 cm.sup.-2. 
FIG. 2 illustrates an adhesive tape 2 comprising a substrate 15 in the form 
of a film or sheet together with first and second adhesive layers 16 and 
17 containing electrically conductive particles 18. 
The substrate 15 in the form of a film (or sheet) is preferably an organic 
film having a high inherent electric resistance of more than 10.sup.9 
.OMEGA.-cm and may be of polyester. The film substrate 15 preferably has a 
thickness of 50 .mu.m to 150 .mu.m, more preferably 75 .mu.m to 135 .mu.m. 
If the thickness of the film substrate 15 is less than 50 .mu.m, the film 
is easily fused and cut by the heat or pressure of the clamping band, and 
thus the insufficient implosion prevention effect is reduced or lost. If 
the thickness of the film is more than 150 .mu.m, the adhesive tape 2 may 
not fully adhere to the CRT when taping and may make the formation of an 
electric circuit difficult. 
In the adhesive tape 2, as in FIG. 3, since the substrate 15 can be highly 
insulative, electrically conductive particles 18 may be dispersed not only 
in the first adhesive layer 15 but also in the second adhesive layer 16, 
although the particles 18 may be dispersed only in one of these two 
adhesive layers 15 and 16. The total amount of the dispersed electrically 
conductive particles 18 must be the same as that in the tape, as shown in 
FIG. 2, i.e., the reduced dispersion amount is preferably from 1 cm.sup.-2 
to 10.sup.5 cm.sup.-2. 
The first adhesive layer 16 is preferably a pressure sensitive adhesive, as 
described in connection with the first adhesive layer 12 in FIG. 2, and 
the second adhesive layer 17 is preferably a thermoset or thermoplastic 
resin type adhesive, as described in connection with the second adhesive 
layer 13 in FIG. 3. Note, as mentioned above, the electrically conductive 
particles 18 may be dispersed not only in the layer 16 but also in the 
layer 17 in this tape of FIG. 3. 
The adhesive tape according to the present invention may be manufactured as 
follows: A cloth or film is dipped in a predetermined solution containing 
a precalculated amount of electrically conductive particles dispersed 
therein, followed by drying and coating or impregnating the dipped and 
dried tape with an adhesive by using a roll coater. The resultant tape is 
then backed with paper and wound onto a roll. Alternatively, a 
precalculated amount of electrically conductive particles is dispersed 
into at least one component of an adhesive and a substrate is coated or 
impregnated with the adhesive, backed with paper, and wound onto a roll. 
Furthermore, before winding or during slitting, the electrically 
conductive particles can be dispersed on a surface of the adhesive tape by 
a quantitative distributor, followed by embedding the particles into the 
adhesive tape with a pressure roller. 
FIG. 4 illustrates the adhesive tape 2 according to the present invention 
after the CRT 3 is clamped with the clamping band 1. After winding and 
applying an adhesive tape 2 according to the present invention completely 
or partially around or near the maximum peripheral portion of the CRT 3, 
the clamping band 1 made of steel or stainless steel is heated to a 
temperature of more than 120.degree. C. and then placed on top of the 
adhesive tape 2. The band 1 is then allowed to cool. During these 
processes, the adhesives 12 and 13 are fused or softened and thus made 
flowable, whereby the electrically conductive particles 14 penetrate into 
the adhesive 13 and are made into contact with or close to each other, as 
shown in FIG. 4, so that the electric resistance of the tape 2 between the 
two major surfaces is reduced to less than 1 M.OMEGA.. As a result, an 
electrical connection between the transparent electrically-conductive film 
4, the clamped tape 2, and the metal clamping band 1 is formed. The metal 
clamping band 1 is connected to the lug 5 which is connected to the ground 
through the wire 7, and thus a flow or removal of electrostatic charges 
through the circuit is obtained. The electric resistance of less than 1 
M.OMEGA., preferably less than 10.sup.4 .OMEGA., most preferably less than 
10 .OMEGA., of the clamped adhesive tape allows the removal of 
electrostatic charges. Although the clamping force applied by the metal 
clamping band 1 depends on the design of the CRT or the structure of the 
metal clamping band 1, this clamping force is usually more than 30 
kgf/cm.sup.2 near the four corners of the CRT and 1 to 10 kgf/cm.sup.2 on 
the flat side portions thereof, which is sufficient to ensure a reduced 
electric resistance of the tape. 
The thus obtained CRT is not only effectively reinforced by the clamping 
band to prevent an implosion thereof, but also is provided with an 
effective circuit for a removal of electrostatic charges, and therefore, 
the CRT is safe, and furthermore, requires no change in the manufacturing 
steps, after the steps described above. This is particularly advantageous 
to industry. 
The invention is now described in detail with reference to examples 
thereof, which in no way limit the scope of the present invention. 
EXAMPLE 1 
A plain glass cloth composed of 30 weft fibers per 25 mm (yarn count: #150) 
and 25 warp fiber per 25 mm (yarn count: #75), and having a thickness of 
0.18 mm, was treated with an aminosilane. Ethylene-acrylic acid copolymer 
(MI=1, content of acrylic acid 8%) having a softening point of 85.degree. 
C., as a thermoplastic adhesive, was fused at 350.degree. C. and extruded 
and laminated on one side of the treated glass cloth at a basis weight 
(amount applied) of 60 g/m.sup.2. An adhesive formulation having butyl 
acrylate (solid content 33%) was added and mixed with iron powders having 
a density of 7.86 g/cm.sup.2, an electric resistance of 
9.8.times.10.sup.-8 .OMEGA.-m, a particle size distribution of from 15 
.mu.m to 135 .mu.m, and a mode particle size of 105 .mu.m (145 mesh) in an 
amount of 0.8% by volume based on the adhesive formulation. This mixture 
was coated on the other side of the glass cloth at a basis weight of 115 
g/m.sup.2 followed by drying, and thus an adhesive tape containing iron 
powders in a reduced dispersion amount of the iron powders of 386.6 
cm.sup.-2 was obtained. 
The characteristics of this tape are shown in Table 1. 
This film was cut to a width of 45 mm, and the resultant tape was wound and 
adhered around the maximum peripheral portion of a 29 inch CRT for color 
TV. An iron band, having an inner periphery length corresponding to 99.5% 
of the maximum periphery of the tube, was placed, after heating to 
500.degree. C., on top of the tape, and the electric resistance of the 
tape between the two major surfaces and the implosion prevention effect of 
the CRT were measured. 
The results are shown in Table 1. 
EXAMPLE 2 
Nickel powders having a mode particle size of 75 .mu.m (about 200 mesh), a 
particle size distribution of 1 .mu.m to 95 .mu.m, a density of 8.85 
g/cm.sup.3, and an electric resistance of 7.24.times.10.sup.-8 .OMEGA.-m 
were applied with vinylidene chloride on both surfaces of a polyester film 
having a thickness of 0.75 mm. The basis weight of the vinylidene chloride 
with the nickel powder was about 50 g/m.sup.2. This pretreated film 
contained nickel powders in a reduced dispersion amount of the nickel 
powders of 1279.2 cm.sup.-2. 
A rubber-based adhesive comprising natural rubber, an adhesivity-providing 
resin, and a filler was applied on both surfaces of the pretreated 
polyester film by dipping. After drying, the basis weight of the 
rubber-based adhesive applied on to the respective surfaces of the film 
was 70 g/m.sup.2. The treated film was backed with a release paper and 
wound onto a roll. 
The film was cut into tapes having a width of 45 mm, and applied to the 
CRT, as in Example 1, in the same manner as in Example 1. 
The results are shown in Table 1, and showed the required effects were 
fully obtained. 
EXAMPLE 3 
A leno glass cloth composed of 16 weft fibers per 25 mm (yarn count: 
#150.times.2) and 16 warp fibers per 25 mm (yarn count: #75) and having a 
thickness of 0.24 mm was treated with vinyl chloride, and an 
ethylene-vinyl acetate copolymer resin (content of vinyl acetate: 10 wt %) 
having a softening point of 95.degree. C. was fused at 400.degree. C. and 
extruded and laminated on one side of the glass cloth at a basis weight of 
65 g/m.sup.2. 
A rubber-based adhesive comprising natural rubber and an 
adhesivity-providing resin was applied on the other side of the glass 
cloth by a calender roll to a basis weight of 160 g/m.sup.2. On this side 
of the glass cloth, aluminum powders having a particle size distribution 
of 50 .mu.m to 350 .mu.m, a mode particle size of 210 .mu.m, a density of 
2.69 g/cm.sup.3, and an electric resistance of 2.75.times.10.sup.-8 
.OMEGA.-m were dispersed in an amount of 25 g/m.sup.2 by a quantitative 
distributor, and the aluminum powders were embedded in the adhesive by a 
pressure roller at a pressure of less than 5 kg/cm.sup.2. The resultant 
tape was backed with paper and wound on roll. The tape had a reduced 
dispersion amount of the aluminum powders of 191.8 cm.sup.-2. 
The tape was cut to a width of 45 mm, and the same tests as in Example 1 
were carried out. 
The results are shown in Table 1. 
EXAMPLE 4 
A glass cloth as used in Example 1 was treated in the same manner as in 
Example 1 to coat ethylene-acrylic acid copolymer resin on one side 
thereof in an amount of 50 g/m.sup.2. An adhesive formation used in 
Example 1 (solid content 33%) was added and mixed with copper powders 
having a particle size distribution of 1.5 .mu.m to 300 .mu.m, a mode 
particle size of 290 .mu.m, a density of 8.85 g/cm.sup.3, and an electric 
resistance of 1.72.times.10.sup.-8 .OMEGA.-m, in an amount of 0.1% by 
volume, and the resultant adhesive was coated on the other side of the 
glass cloth at a basis weight of 85 g/m.sup.2, and dried. The resultant 
adhesive tape had a reduced dispersion amount of copper powders of 1.97 
cm.sup.-2. 
The same tests as in Example 1 were carried out. 
The results are shown in Table 1. 
EXAMPLE 5 
A rubber-based adhesive formulation comprising natural rubber, an 
adhesivity-providing resin, and a filler was applied on one side of a 
polyester film having a thickness of 0.75 mm, and dried. Then 100 parts by 
weight of an epoxy compound containing dicyandiamide (bisphenol A type: 
epoxy value 285) was added to and mixed with 0.9 parts by weight of silver 
powders having a particle size distribution of 100 .mu.m to 200 .mu.m, a 
mode particle size of 150 .mu.m, a density of 10.5 g/cm.sup.3, and an 
electric resistance of 1.62.times.10.sup.-8 .OMEGA.-m. The resultant 
adhesive was coated over the top side of the film by a hot melt coater 
heated at 75.degree. C., to a basis weight of 25 g/m.sup.2. The coated 
film was backed with a release paper and wound on a roll, and an adhesive 
tape having a reduced dispersion amount of silver powders of 1.21 
cm.sup.-2 was obtained. 
The same tests as in Example 1 were carried out. 
The results are shown in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 
__________________________________________________________________________ 
Tape thickness (mm) 
0.250 
0.205 
0.295 
0.260 
0.180 
Peeling adhesion to glass 
1100 680 860 580 550 
(gf/25 mm).sup.1) 
Peeling adhesion to iron 
420 690 400 400 300 
(gf/25 mm).sup.2) 
Shear adhesion (kgf/cm.sup.2).sup.3) 
15.5 9.7 13.3 18.7 25.3 
Electric resistance between.sup.4) 
9.6 12.5 23.8 5.4 7.5 
surfaces (m.OMEGA./layer) 
Taper block test (sec).sup.5) 
35.8 25.4 46.5 65.2 16.3 
Load sliding test (mm).sup.6) 
up to 1 
up to 1 
up to 1 
up to 1 
2.0 
5 feet pound test.sup.7) 
2 5 1 3 3 
Electric resistance between.sup.8) 
glass and band (m.OMEGA.): 
before clamping 
5.7 .times. 10.sup.14 
6.5 .times. 10.sup.15 
2.3 .times. 10.sup.13 
4.4 .times. 10.sup.14 
3.6 .times. 10.sup.9 
after clamping: 
average at four corners 
1.56 2.70 0.30 3.50 0.86 
average at flat sides 
16.5 45.0 10.4 19.8 6.9 
__________________________________________________________________________ 
In Table 1, the characteristics were measured by the following method. 
1) Peeling adhesion to glass: 
180.degree. peeling off test at 300 mm/min at 30.degree. C. 
2) Peeling adhesion to iron: 
180.degree. peeling off test at 300 mm/min at 30.degree. C. after sample 
was pressed at 300.degree. C. for 10 seconds. 
3) Shear adhesion: 
The shearing force at 50 mm/min at 23.degree. C., after the tape was 
sandwiched between stainless steel (SUS) plates and pressed at 300.degree. 
C. for 10 seconds. 
4) Electric resistance between the two major surfaces of the tape: 
Copper foils were applied on both surfaces of the tape, which was fixed on 
the surface of an iron column having a diameter of 50 mm. The tape was 
faced down and pressed at a pressure of 5 kg/cm.sup.2 and at 300.degree. 
C., and during the pressing, an electric resistance between the copper 
foils was determined. 
5) Taper block test: 
Two taper iron blocks composing an iron column having a size of 25 
mm.times.25 mm and a height of 70 mm are separated at the middle of the 
column by a sliding angle of 5.degree., and an adhesive tape having a size 
of 25 mm.times.25 mm was adhered between the two taper blocks to form a 
column. The upper block was heated to 300.degree. C. and a load of 10 kg 
was applied thereto. In this state, the time until the upper block fell 
down by slipping from the adhesive tape was determined. 
6) Load sliding test: 
A load of 120 kg was applied to a CRT with an adhesive tape clamped with a 
clamping band at 70.degree. C. for 30 minutes, and the maximum amount of 
sliding determined. 
7) 5 feet pound test: 
A CRT was positioned with the front side thereof facing upward, and a steel 
ball having a weight of 500 g was dropped thereon from a height of 1.5 m. 
The number of cracks passing through the portion under the clamping band 
was determined. 
8) Electric resistance between glass and band: 
Copper foils were adhered at the four corners and at the middle of the four 
sides of the CRT before a clamping band was applied. After the adhesive 
tapes were applied, other copper foils were applied to the adhesive tapes 
at the portions just above the previously applied copper foils, and then 
clamping was effected. The electric resistance between the corresponding 
two copper foils were then determined.