JPH077608B2 - Deformed conductive elastomer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention exhibits a high resistance value in a non-deformed state such as no pressure or extension, and the resistance value is suitably reduced during deformation such as compression, extension, bending or twisting. In particular, the present invention relates to a deformed conductive elastomer having excellent tensile strength and durability not only against compression deformation but also against elongation deformation.

[0002]

2. Description of the Related Art As conventional deformed conductive elastomers of this type, synthetic rubbers such as silicone rubber, ethylene propylene rubber and chloroprene rubber, and non-conductive elastomers such as thermoplastic elastomers exhibiting rubber elasticity have been used.
A pressure-sensitive conductive rubber obtained by mixing and dispersing a conductivity-imparting agent such as metal particles, carbon black, and graphite particles has been known, and the same non-conductive elastomer as described above is added to metal fibers, carbon short fibers, A stretched conductive elastomer obtained by mixing and dispersing a conductivity-imparting agent such as a flaky conductive filler obtained by nickel-plating mica is known. The pressure-sensitive conductive rubber is one whose resistance value changes mainly due to pressure and compression deformation, and the stretched conductive elastomer whose resistance value mainly changes due to stretching deformation.

As a concrete example, regarding the pressure-sensitive conductive rubber, for example, Japanese Patent Publication No. 56-9187 and Japanese Patent Publication No. 56-54019 disclose, as conductive particles, gravel-like artificial graphite with corners dropped. A pressure-sensitive conductive rubber composition using particles has been disclosed, and JP-A-62-1126 has also disclosed.
No. 41 discloses a pressure-sensitive conductive elastomer composition using conductive particles obtained by firing and carbonizing spherical particles of a polymer material, and further, JP-B-60-722 and JP-B-SHO. In JP 60-723, conductive metal particles surface-treated with a silane coupling agent are dispersed in a liquid silicone rubber, and n-propyl alcohol, n-propyl alcohol having a solubility parameter of 9.8 or more is used as a foaming agent.
A pressure-sensitive conductive material using an organic compound such as butyl alcohol or an organic compound having an N-nitroso group is disclosed. On the other hand, as a specific example of the stretched conductive elastomer, for example, in JP-A-61-80708, polyurethane having a high molecular elastomer has a ratio of a surface inner diameter to a thickness of 2: 1 or more and less than 100: 1. Disclosed is a deformed conductive polymer elastomer in which flaky conductive filler made by plating nickel or copper on flaky mica or glass is mixed and dispersed.

[0004]

However, the above-mentioned conventional pressure-sensitive conductive rubbers and stretched conductive elastomers have useful functions only for specific deformation modes, and both of them are described below. There was a problem as shown. That is, the pressure-sensitive conductive rubber shows a good change in resistance value only under pressure and compression deformation, and does not show a suitable change in resistance value under extension deformation. The stretched conductive elastomer has a problem in that it exhibits a favorable change in resistance value only with respect to extensional deformation, and does not exhibit an appropriate change in resistance value with respect to pressure and compression deformation. . This is a problem inevitably caused by the different purposes and uses of the two. Further, as the pressure-sensitive conductive rubber, it has been attempted to use one prepared by mixing conductive particles made of graphite particles or spherical carbon particles in a non-conductive elastomer, but with such a simple mixing means, , The conductive particles come into contact with or separate from each other based on the deformation of only the non-conductive elastomer, which is because the properties such as rubber elasticity of the conventional non-conductive elastomer do not meet the required conditions. As a result, the resistance value changes drastically with respect to the pressure change due to pressurization and compression deformation, that is, the sensitivity becomes excessively high, and the preferable characteristic that the resistance value gradually changes over a wide pressure change range cannot be obtained. However, this also causes a problem that desired linearity cannot be obtained in the resistance change characteristic with respect to pressure change. Furthermore, in this type of pressure-sensitive conductive rubber,
In order to appropriately reduce the resistance value during pressurization and compression deformation, a relatively large amount of conductive particles must be blended in the non-conductive elastomer, which results in an apparent hardness. As the material becomes higher, the material itself becomes brittle, which causes a problem that bending strength and tensile strength are reduced.

The present invention has been made in view of the above circumstances, and there are problems in resistance value change due to differences in deformation modes, resistance change characteristics such as resistance value change range and linearity, and materials. By comprehensively examining the problems of strength, etc., it has sufficient strength against various deformation modes such as compression, extension, bending, twisting, etc. and shows a good change in resistance value, and changes in resistance value. It is a technical object to provide a novel deformable conductive elastomer having a wide range and excellent linearity, durability and responsiveness.

[0006]

The deformed conductive elastomer according to the present invention is characterized by having the following constitution in order to achieve the above-mentioned technical problems. That is, in the non-conductive elastomer, the insulating elastic fiber having a thickness of 100 denier or less, the elastomer particles having a particle diameter of 10 to 300 μm, the conductive particles having a particle diameter of 1 to 40 μm, and the particle diameter of 10 to The gist is that 150 μm hollow elastic microspheres are dispersed.
And, if necessary, silicone rubber is adopted as the non-conductive elastomer, or an elastomer composed of liquid silicone rubber and silicone varnish and raw silicone rubber or a silicone adhesive containing these as the main components is adopted. . Further, the insulating elastic fiber is a polyethylene fiber, a polyamide fiber, an aramid fiber, a polyester fiber or a polyurethane fiber having a curved amorphous shape or a repeating stitch, or a composite fiber thereof, and is subjected to a surface activation treatment. Adopt one. In this case, as the surface activation treatment, a treatment with a silane coupling agent, a titanium coupling agent, a chromium coupling agent, ultraviolet rays, plasma or an ion beam can be used. Further, crosslinked silicone rubber powder is adopted as the elastomer particles. As the conductive particles, spherical carbon particles having insulating particles having a particle diameter of 0.05 to 0.2 μm adhered to the surface at a surface integration ratio of 30 to 70% are used. In this case, calcium particles can be used as the insulating particles. Further, as the hollow elastic microsphere, a hollow shell of a copolymer of vinylidene chloride and acrylonitrile is adopted.

[0007]

As the non-conductive elastomer, conventional ones can be used, and among them, the one-component room temperature curing silicone rubber is preferable. As a 1-liquid room temperature curing silicone rubber,
Examples of the condensation type include those that undergo hydrolysis by moisture in the air to promote crosslinking, and oxime type, alcohol type, acetone type, acetic acid type and the like can be used. Among these, the acetone type and acetic acid type have curing rate, corrosiveness,
It is preferable to use an oxime type or an alcohol type because the characteristics are inferior in terms of odor and the like. If necessary, a silicone varnish, more specifically, a silanol group-containing polysiloxane may be added to the liquid silicone rubber with toluene,
A mixture obtained by diluting with an organic solvent such as xylene and a silicone raw rubber composed of a linear polysiloxane having an average molecular weight of 150,000 to 500,000, or the above liquid silicone rubber, a silicone varnish, a silicone raw rubber, a filler, By using a mixture containing a silicone adhesive containing a plasticizer as a main component, it is possible to improve the adhesive force with the conductive particles and the tear strength of the deformed conductive elastomer, as compared with the case of the liquid silicone rubber alone. .

As the insulating elastic fiber which is the first characteristic constituent feature of the present invention, a large number of curved amorphous fibers or stretchable fibers having repeated stitches are used. The regular fiber may be a long fiber, but the length is preferably 3 to 6 mm and the compounding amount is 0.01
Preferably 0.1 to 0.1% by weight, and the fiber having the repeating stitches preferably has the stitches regularly arranged at a pitch of 0.2 to 1.0 mm. Examples thereof include rubber knitting, garter knitting, and the like. The length of the amorphous fiber is 3
If it is less than 6 mm or more than 6 mm, it is disadvantageous in terms of dispersibility in non-conductive elastomer, processability, moldability and reinforcement, and if the pitch of the fibers having the repeating stitches is less than 0.2 mm. Has poor elasticity and has a pitch of 1.0 mm
If it exceeds, there is a problem that the reinforcing effect is insufficient. As a material for this fiber, organic fibers such as polyethylene, polyamide, polyester, polyurethane, acrylic and aramid can be used alone or in combination, and the thickness thereof needs to be 100 denier or less, and the thickness is 1
If it exceeds 00 denier, there is a problem that the deformed conductive elastomer becomes hard and difficult to deform. still,
It is more preferably 7 to 100 denier, and if it is less than 7 denier, the reinforcing effect cannot be expected so much. As the surface activation treatment of this fiber, when the non-conductive elastomer is a silicone rubber, .gamma.-aminopropyltriethoxysilane H2 NC3 H6 Si
(OC2 H5) 3, vinyltrichlorosilane CH2 = C
Treatment with a silane coupling agent such as HSiCl3 is exemplified (may be used by mixing in silicone rubber), and in the case of other non-conductive elastomer, titanium coupling agent is used. Examples thereof include chemical surface activation treatment using a chromium-based coupling agent and the like, and physical surface activation treatment using ultraviolet rays, plasma, ion beams and the like. The above-exemplified fibers are rich in stretchability in the three-dimensional directions, and even when mixed in a non-conductive elastomer, they can exhibit sufficient followability and can withstand various deformations. By physically or physically performing the surface activation treatment, the adhesive force to the non-conductive elastomer is enhanced, and the physical strength and durability of the deformed conductive elastomer can be improved.

The conductive particles dispersed as a conductivity-imparting agent in the non-conductive elastomer are nickel,
It is possible to use metal particles made of copper, gold, silver, stainless steel, aluminum, iron, chromium or the like or alloys thereof, graphite, carbon particles and the like. Specific examples of these include mesocarbon microbeads obtained by heating microspheres of styrene, vinyl chloride, vinylidene chloride or the like in air to 300 ° C. and then firing in inert gas to 1000 ° C., or phenol resin. , Glass-like fine spherical carbon particles (independent particles close to a true sphere) obtained by heat-treating fine spherical particles of furan resin or the like at 800 to 1000 ° C. in a vacuum. Regarding the particle size of the conductive particles, if the particle size is less than 1 μm, it is difficult to manufacture the particles, and the smaller the particle size, the less the resistance change. On the other hand, the particle size is 40
If it exceeds μm, the resistance change becomes rough, so 1 to 40μ
It must be m. The content of the conductive particles in the total composition is preferably 25 to 45% by volume. When the content is less than 25% by volume, the resistance becomes high, and when the content exceeds 45% by volume, the normal conductivity is increased. It tends to be in a state. Further, as a means for improving the adhesive force between the conductive particles and the non-conductive elastomer, an appropriate surface treatment of the conductive particles can be mentioned. As an example of a suitable surface treatment of the conductive particles, when the conductive particles are spherical carbon particles, insulating particles having a particle diameter of 0.05 to 0.2 μm are added to the surface of the conductive particles to a surface integral of 30 to 70%. It is exemplified to attach at a rate. Ultrafine particles of calcium, titanium oxide, silicon oxide or the like can be used as the insulating particles. In addition, by adhering the insulating particles to the surface of the conductive particles at an appropriate surface integration ratio, the degree to which the conductive particles become conductive when they contact each other is moderately moderated. As a result, the change in resistance value with respect to deformation of the deformed conductive elastomer becomes gentle, and the linearity of the resistance value change characteristic with respect to deformation is improved.

The second characteristic constitutional requirement of the present invention, the elastomer particles, is an elastomer exhibiting rubber elasticity or a crosslinked rubber particle. By mixing and dispersing the elastomer particles in the deformed conductive elastomer, the deformed conductive elastomer is obtained. The purpose of this is to build a polymer alloy (sea, island structure) of a conductive elastomer, which lowers the hardness that increases due to the blending of the conductive particles, and increases the maximum limit of elongation and rubber elasticity. It is possible to prevent the deformed conductive elastomer from becoming brittle. Therefore, the deformed conductive elastomer has sufficient strength not only against compression deformation but also against elongation, twisting, and bending deformation, and exhibits good resistance change against all these deformations. Is possible. Examples of the elastomer particles include thermoplastic elastomers such as copolymers of polystyrene and butadiene rubber, copolymers of polyethylene and ethylene propylene rubber, copolymers of urethane and polyester, silicone rubber,
Crosslinked synthetic rubber such as fluororubber, EPDM rubber, acrylonitrile rubber, chloroprene rubber, and styrene-butadiene rubber crushed by a low-temperature crusher or manufactured by an abrasion mill can be used. Amorphous or spherical powder It may be in the form of particles or particles. Crosslinked silicone rubber powder is suitable when the above non-conductive elastomer is made of silicone rubber, but when other elastomer particles are used, such as silane coupling agent is used. It can also be used after a suitable surface treatment. The particle size of the elastomer particles is required to be 10 to 300 μm, and the particle size of 50 to 100 μm is particularly preferable in view of elongation deformation. Particle size is 1
If it is less than 0 μm, crushing is difficult and the effect of reinforcement cannot be expected so much, and if the particle size exceeds 300 μm, the conductive particles are coarsely distributed, resulting in a conductive property when connecting electrodes. There is a problem that it becomes difficult for the conductive particles and the electrode to come into contact with each other, and the resistance value varies.

The third characteristic constitutional requirement of the present invention, the hollow elastic microspheres, are hollow microspheres excellent in elasticity and shock absorption, and are mixed and dispersed in a non-conductive elastomer. As a result, it is possible to reduce the apparent hardness, which is increased due to the blending of the conductive particles, and to improve the durability and impact strength, which are difficult points of the non-conductive elastomer, especially the silicone rubber. As the hollow elastic microspheres, a copolymer of vinylidene chloride and acrylonitrile is preferably used as a shell, and an encapsulation product containing isobutane as a swelling agent and encapsulating it is exemplified by an expanded and dried PVDC microballoon. Of course, it is not limited to this. The particle size of this hollow elastic microsphere is 1
It is necessary to set the particle size to 0 to 150 μm, and more preferable from the viewpoint of elasticity and impact absorption, the particle size is 20 to 80 μm and the average particle size is 50 μm.
The thickness of the shell wall is about 0.1 μm. If the particle size is less than 10 μm, the particles become fine and the shock absorption and vibration absorption are reduced, while the particle size is 150 μm.
When it exceeds m, the proportion of the hollow cells, that is, the hollow elastic microspheres, becomes excessively high locally or entirely, and the strength of the deformed conductive elastomer decreases. The compounding ratio of the hollow elastic microspheres in the entire composition is preferably 10 to 35% by volume, and 10% by volume.
When it is less than the above range, the durability and shock absorption cannot be improved so much, while when it exceeds 35% by volume, the resistance change is small and the resistance change characteristic against deformation is deteriorated. The hollow elastic microspheres may be prepared by previously expanding them as described above. However, unexpanded ones are mixed and dispersed in the elastomer phase, and the mixture is expanded by heating to obtain the hollow elastic microspheres having the above-mentioned particle size. It can also be adjusted to a sphere. However, in this case, there is a problem that the control of the curing conditions of the non-conductive elastomer and the timing of expansion is delicate and the production becomes difficult, so it is preferable to mix and disperse the expanded hollow elastic microspheres. When the deformed conductive elastomer containing such hollow elastic microspheres is compared with the deformed conductive elastomer obtained by adding the foaming agent, in the case of adding the foaming agent, the shape and size of the foam cell are increased. On the other hand, the hollow elastic microspheres have a spherical shape and a relatively uniform particle size, and the size and amount of the hollow cells can be controlled relatively easily. -Shaped elastic microspheres are much more durable and shock absorbing than foam cells. As a result, the deformed electrically conductive elastomer of the present invention containing the hollow elastic microspheres exhibits excellent durability against shock and deformation and shock absorption as compared with those obtained by adding the foaming agent. .

As described above, the deformable conductive elastomer according to the present invention has a denier of 100 denier or less in order to increase the tensile strength particularly against extensional deformation and to suppress the hardness which is increased due to the blending of the elastomer itself to the maximum limit value or less. Of the insulating elastic fiber, conductive particles having a particle diameter of 1 to 40 μm for facilitating the production of particles and appropriately increasing resistance change, and shock absorbing and vibration absorbing The hollow elastic microspheres having a particle size of 10 to 150 μm and the hardness increased due to the blending of the conductive particles are provided in order to improve the strength by appropriately improving the ratio occupied by the hollow portions. In order to improve the brittleness by reducing it, it is necessary to construct a polymer alloy (sea, island structure) of deformed conductive elastomer, facilitate crushing of particles, and optimize the distribution of conductive particles. Since the elastomer particles having a particle size of 10 to 300 μm are dispersed in a non-conductive elastomer, not only sufficient strength can be obtained against any deformation such as compression, extension, twisting and bending. The characteristics of the resistance change with respect to each of these deformations are as follows. That is, with respect to compressive deformation, the elastomer particles and the hollow elastic microspheres in a suitable distribution state in the non-conductive elastomer are pressed by the pressing force and gradually considered in a three-dimensional direction if microscopically considered. Therefore, the conductive particles mixed and dispersed together with each other are approached in a three-dimensional direction, which gradually increases the number of conductive particles which are brought into a conductive state. The resistance value gradually decreases as the applied pressure increases. Further, with respect to the elongation deformation, the elastomer particles mixed and dispersed with the non-conductive elastomer and the hollow elastic microspheres are pulled, so that a stress is applied to the center of the tension portion in a direction orthogonal to the tension direction, Due to this stress, the conductive particles approach each other in the three-dimensional direction, and due to this, the number of conductive particles that become conductive gradually increases, so the resistance gradually increases as the tensile force increases. It will decrease. Furthermore, since the particle diameter of the conductive particles is appropriate, that is, the distribution state of the conductive particles is appropriate, the torsional and bending deformations are resisted by the action of both the compression deformation and the extensional deformation. The value will change satisfactorily.

[0013]

EXAMPLES Examples of the present invention will be described below, but these examples are not intended to limit the present invention. First, Example 1 of the modified conductive elastomer according to the present invention will be described. Silicone rubber (KE-971
U, manufactured by Shin-Etsu Chemical Co., Ltd.) 100 parts by weight of a cross-linking agent (C-8A, manufactured by Shin-Etsu Chemical Co., Ltd.) was blended and kneaded, and then press-cured at 160 ° C. for 15 minutes. 50 ~ 300μ with rubber crusher
crushed to m, and further SUS304 stainless steel # 70
Sieve was filtered through a mesh filter to obtain a silicone rubber powder. In addition, a large number of linear polyamide short fibers with a thickness of 13 denier and a length of 6 mm (made by Kanebo Co., Ltd.)
Was subjected to surface activation treatment with an amino silane coupling agent (KBE903, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, 42.1 parts by weight (77 g) of glassy fine spherical carbon particles (glass carbon-P, GP-5X, manufactured by Owada Carbon Industry Co., Ltd.) having a particle diameter of 1 to 12 μm are added to 11 parts by weight of the above silicone rubber powder ( 20 g) and hollow elastic microspheres (EXPANCEL-DE551) having a shell of a copolymer of vinylidene chloride and acrylonitrile having a particle size of 10 to 100 μm and an average particle size of 40 μm.
0.43 parts by weight (0.8 g) of Expancel (Sweden) was mixed and dispersed. Then, 17.3 room temperature curing silicone rubber (SE5002, manufactured by Toray Dow Corning Co., Ltd.) 27.3 parts by weight (50 g) and silicone adhesive (YR3340, manufactured by Toshiba Silicone Co., Ltd.)
19.1 parts by weight (35 g) and 0.1 part by weight (0.2 g) of the above polyamide short fibers were mixed in a mixer for 3 minutes, and then the above silicone rubber powder and hollow elastic micro Glass-like fine spherical carbon particles in which spheres were mixed and dispersed were added and mixed for another 3 minutes to thoroughly degas.
Then, add this mixture to a polypropylene mold (1
(50 mm × 200 mm × 2.0 mm) and formed into a sheet, and allowed to stand for 24 hours at a temperature of 10 ° C. and a humidity of 80% to cure, and then heat treated at 70 ° C. for 1 hour. In this case, the fine spherical carbon particles described above have 3
Insulating particles are attached at a surface integration ratio of 0 to 70%. An example of the method for producing such fine spherical carbon particles will be described.
Particles having an epoxy resin, a polyimide resin, or the like as a core are mother particles, and ultrafine particles of an insulating inorganic material such as calcium, titanium, or silica having a particle size of 0.05 to 0.2 μm are child particles,
An ordered mixture is formed by implanting, fixing and arranging the child particles on the mother particles using a hybridizer or the like. Then, by heating this in a vacuum or in an inert gas at a temperature of 800 to 1000 ° C. to carbonize it, fine spherical carbon particles to which the above-mentioned insulating particles are attached can be obtained. The change in resistance to compressive deformation and the change in resistance to extensional deformation of the sample of the deformed conductive elastomer obtained as described above were measured by the following means. Figure 4
A measuring circuit for measuring characteristics of resistance change due to compressive deformation is shown. E is a DC constant voltage power source, R is a standard resistor, and P is a standard resistor.
Is pressurizing speed (5 mm / min), V is voltage change, C is sample (1
0 mm × 10 mm × 2.0 mm). Further, FIG. 5 shows a specific measuring device, A is a pressure and elongation tester, B is a small load converter, D is a dynamic strain measuring device, F is an analyzing recorder, and G1 and G2 are measuring electrodes (gold-plated copper). A printed circuit board (20 mm × 20 mm × 1.6 mm) is shown. For the measurement, the sample C is placed between the measurement electrodes G1 and G2, and a small load converter B for measuring the applied pressure is further installed under the electrodes G1 and G2 to apply pressure from above the sample C. The measurement electrode G1 was lowered and pressurized at a speed P, the resistance value was calculated from the voltage V at this time, and the pressing force was output from the dynamic strain measuring device D. The measurement results are shown as Example 1 in the graph of FIG. 1 (graph on a logarithmic scale). FIG. 6 shows a measuring circuit for measuring the characteristic of resistance change with respect to extensional deformation, and E, R, V
For, use the same one as shown in Fig. 4 above.
H1 and H2 are measurement electrodes (gold-plated copper-bonded printed circuit board, 1
0 mm x 4 mm x 1.6 mm), T is the extension speed (5 mm / min),
I represents a sample (35 mm × 4.0 mm × 2.0 mm). In addition, FIG. 7 shows a specific measuring device, which includes A, B, D, F,
As for E and R, the same one as shown in FIG. 5 is used, and the sample I with the electrodes H1 and H2 connected is used as a chuck J.
1 and J2, the chuck J1 was lowered at the extension speed T to extend the sample I, the resistance value was calculated from the voltage V at this time, and the extension force was output from the dynamic strain measuring device D. The results of this measurement are shown as Example 1 in the graph of FIG. 2 (graph on semilogarithmic scale).

Next, Example 2 of the deformed conductive elastomer according to the present invention will be described. Silicone rubber (SH
871 U, manufactured by Toray Dow Corning Co., Ltd.) 100 parts by weight, and 0.45 parts by weight of a cross-linking agent (RC-4, manufactured by Toray Dow Corning Co., Ltd.) were mixed and kneaded at 170 ° C.
The cross-linked silicone rubber, which has been press-cured for 15 minutes at 200 ° C. and then secondarily cured at 200 ° C. for 24 hours, is milled to 60 to 400 μm with an abrasion mill and further SUS3
A 04 # 70 mesh filter was sieved to obtain a silicone rubber powder. Also, the size obtained by knitting 13 denier polyamide fiber with a pitch of 0.3 to 0.7 mm is 250 mm x 250 mm.
The stocking fabric (made by Kanebo Co., Ltd.) was subjected to surface activation treatment with an amino silane coupling agent (KBE903, manufactured by Shin-Etsu Chemical Co., Ltd.). Then, glassy fine spherical carbon particles having a particle diameter of 1 to 12 μm (glass carbon-P, GP-5X, manufactured by Owada Carbon Industry Co., Ltd.)
40.8 parts by weight (65 g) of the above silicone rubber powder 1
8.8 parts by weight (30 g) and hollow elastic microspheres (F-80ED) having a shell of a copolymer of vinylidene chloride and acrylonitrile having a particle diameter of 20 to 80 μm.
(Matsumoto Yushi-Seiyaku Co., Ltd.) 0.4 parts by weight (0.6 g) were mixed and dispersed. Next, 40 parts by weight (64 g) of a one-part room temperature curing silicone rubber (KE-445, manufactured by Shin-Etsu Chemical Co., Ltd.) and an amino silane coupling agent (KB
E903, manufactured by Shin-Etsu Chemical Co., Ltd.) (0.3 parts by weight (0.5 g)) was mixed in a mixer for 5 minutes, and then the silicone rubber powder and hollow elastic microspheres were mixed and dispersed therein. The glass-like fine spherical carbon particles thus prepared were added, and the mixture was further mixed for 5 minutes and thoroughly degassed. Then, a polyethylene mold (200 mm x 200 mm x 2.0 m) is used to mix this mixture with the above-mentioned polyamide fiber cloth.
m), the above-mentioned cloth is formed into a sheet shape so as to be arranged in the central portion in the thickness direction, and allowed to stand for 24 hours at a temperature of 10 ° C and a humidity of 80% to be cured, and then at 70 ° C. It heat-processed for 1 hour. The change in resistance to compressive deformation and the change in resistance to extensional deformation of the sample obtained as described above were measured by the same method as in Example 1 described above, and the measurement results are shown in FIGS. This is shown as Example 2 in the graph.
In addition, what is shown as a comparative example in the graphs of FIG. 1 and FIG.
It is a measurement result about the sample in which the polyamide short fiber was not added in the formulation of Example 1. Further, the graph shown in FIG. 3 (graph on a semilogarithmic scale) shows the results of the durability test of Example 1 and the comparative example, each test being ON for 1 second at a load of 4 kg / cm 2 (loaded condition), It is shown that the repetition of OFF (no load state) for 3 seconds is performed 1,000,000 times, and the extension force and the change in resistance value at the 1,000,000th time are shown together with the data at the first time. Further, for each of the samples of the above-mentioned Examples 1, 2 and Comparative Examples, the measurement results for compressive deformation are shown in Table 1, the measurement results for extensional deformation are shown in Table 2, the measurement results for bending deformation are shown in Table 3, and the torsional deformation is shown. Table 4 shows the measurement results for the above as numerical values. In addition, the measurement of the bending deformation is performed on the sample (35 mm × 4.0 mm × 2.0 m
Electrodes are connected to both longitudinal ends of m), and one end in the longitudinal direction of this sample is fixed and a load is applied to the other end to cause bending deformation, and the electrical resistance value at this time is extracted. In addition, the measurement of the torsional deformation was performed by connecting electrodes to both ends of the sample (35 mm × 4.0 mm × 2.0 mm) in the longitudinal direction and fixing one end of the sample in the longitudinal direction. Then, a rotational force is applied to the other end around a central axis (a central axis extending in the longitudinal direction) to cause torsional deformation, and the electrical resistance value at this time is extracted.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

FIG. 8 and FIG. 9 show the internal structure of the deformed conductive elastomer mixed with the insulating elastic fiber having the repeated stitches as in the case of the second embodiment. In addition, insulating elastic fibers 2 having repeating stitches, elastomer particles 3 ... 3, hollow elastic microspheres 4 ... 4, and conductive particles 5 ... 5 are dispersed.

FIG. 10 shows the internal structure of the deformed conductive elastomer mixed with the insulating elastic fibers composed of a large number of short fibers as in the case of Example 1 (reference numeral 1).
To 5 are the same constituent elements as above), the insulating elastic fiber 2 ...
No. 2 has a curved shape due to the kneading work by the mixer, and the individual directions are not uniform. Therefore, the deformed conductive elastomer can be used not only in a sheet shape but also in a block shape.

In place of the insulating elastic fiber (polyamide fiber) used in Examples 1 and 2, ultra-high strength polyethylene fiber such as (Techmilon, manufactured by Mitsui Petrochemical Co., Ltd.) or (Spectra 900, Alternatively, it is also possible to use Spectra 1000, manufactured by Allied Company (USA), etc. When using this type of fiber,
It can be expected that the material strength will be further improved.

[0022]

As described above, according to the deformed conductive elastomer of the present invention, X,
Insulating elastic fiber, which is a reinforcing material that can expand and contract in the three-dimensional directions of the Y and Z axes, elastomer particles with rubber elasticity, hollow elastic microspheres rich in elasticity and shock absorption, and the particle size is appropriate By mixing and dispersing with the conductive particles set to, like conventional pressure-sensitive conductive rubber that exerts its function only against compression deformation and stretched conductive elastomer that exerts its function only against extensional deformation. Not only can a specific deformation mode be dealt with, but also resistance changes can be satisfactorily exhibited against any deformation such as compression, expansion, twisting, bending, etc., and a sufficient function can be exhibited, so that the application can be expanded. In addition, by incorporating insulating elastic fibers, the tensile strength and durability during elongation can be significantly improved, and by incorporating hollow elastic microspheres, durability against shock load and shock absorption can be improved. By incorporating elastomer particles, the sea layer containing conductive particles and hollow elastic microspheres in the non-conductive elastomer and the island layer structure of the elastomer particles were constructed, and the strength against compression and extension loads was built. In addition, the durability is improved and the range of change in resistance value is expanded.Furthermore, not only the linearity of the resistance change characteristic with respect to each deformation is improved but also the responsiveness is improved due to the interaction of each of the above constituent elements. Will be planned. Further, by subjecting the insulating elastic fiber to the surface activation treatment, the adhesive force with the non-conductive elastomer is improved, and the strength and durability against each deformation are further improved. Further, by adhering the insulating particles to the surface of the conductive particles at an appropriate surface integral ratio, not only the adhesive force with the non-conductive elastomer is improved, but also the resistance change with respect to each deformation becomes gentle. Further, the linearity of the resistance change characteristic with respect to each deformation can be further improved.

[Brief description of drawings]

FIG. 1 is a graph showing resistance change characteristics with respect to compressive deformation of Example 1 and Example 2 and a comparative example.

FIG. 2 is a graph showing resistance change characteristics with respect to extensional deformation in Examples 1 and 2 and Comparative Example.

FIG. 3 is a graph showing resistance change characteristics with respect to durability tests of Example 1 and Comparative Example.

FIG. 4 is a measurement circuit diagram for compression deformation of the first and second embodiments.

FIG. 5 is a schematic configuration diagram showing a specific measuring device for compressive deformation in Examples 1 and 2.

FIG. 6 is a measurement circuit diagram for extensional deformation of the first and second embodiments.

FIG. 7 is a schematic configuration diagram showing a specific measuring device for extensional deformation in Examples 1 and 2.

FIG. 8 is a schematic cross-sectional view showing an internal structure of a modified conductive elastomer obtained by mixing insulating elastic fibers having repeating stitches.

FIG. 9 is an enlarged schematic cross-sectional view showing an internal structure of a deformed conductive elastomer in which insulating elastic fibers having repeating stitches are mixed.

FIG. 10 is a schematic cross-sectional view showing an internal structure of a deformed conductive elastomer in which a curved amorphous material is mixed as an insulating elastic fiber.

[Explanation of symbols]

 1 Non-Conductive Elastomer 2 Insulating Elastic Fiber 3 Elastomer Particles 4 Hollow Elastic Microsphere 5 Conductive Particles

Claims (8)

[Claims] 1. A non-conductive elastomer having a thickness of 10
Insulating elastic fibers having a denier of 0 or less, elastomer particles having a particle size of 10 to 300 μm, and a particle size of 1 to 40
A deformed conductive elastomer, wherein conductive particles of μm and hollow elastic microspheres having a particle size of 10 to 150 μm are dispersed. 2. The deformed conductive elastomer according to claim 1, wherein the non-conductive elastomer is composed of silicone rubber or liquid silicone rubber, and silicone varnish and raw silicone rubber or a silicone adhesive containing these as the main components. 3. The insulating elastic fiber is a polyethylene fiber, a polyamide fiber, an aramid fiber, a polyester fiber or a polyurethane fiber or a composite fiber thereof, which is curved and has amorphous or repeating stitches, and is surface-treated. The deformed conductive elastomer according to claim 1 or 2. 4. The deformed conductive elastomer according to claim 3, wherein the surface activation treatment is a treatment with a silane coupling agent, a titanium coupling agent, a chromium coupling agent, ultraviolet rays, plasma or an ion beam. 5. The deformed conductive elastomer according to claim 1, wherein the elastomer particles are crosslinked silicone rubber powder. 6. The conductive particles are spherical carbon particles, and insulating particles having a particle diameter of 0.05 to 0.2 μm are adhered to the surface of the conductive particles at a surface integration ratio of 30 to 70%. Item 6. The deformed conductive elastomer according to any one of items 1 to 5. 7. The deformed conductive elastomer according to claim 6, wherein the insulating particles are calcium particles. 8. The deformed conductive elastomer according to claim 1, wherein the hollow elastic microsphere has a shell of a copolymer of vinylidene chloride and acrylonitrile.