JPH02186604A - Pressure-sensitive resistance changing type conductive composition - Google Patents

Abstract

PURPOSE:To obtain a composition, which shows electric resistance substantially lower than that of the case where electric resistance is compressed, and to obtain the composition which gives a pressure-sensitive conductive body with which resistance is smoothly reduced by the increase of pressuring force by a method wherein the title conductive composition is composed of an organic polymer material, a semiconductor material having the electric conductivity less than the specific ratio of the conductive material, and an insulating material. CONSTITUTION:The title composition contains an organic polymer material, a conductive material, a semiconductor material having electric conductivity of 1/100 or less of that of the conductive material and an insulating material. As the organic polymer material used, the thermosetting resin such as phenol resin, urea resin, melamine resin, silicon resin, polyurethane resin and the like, and the thermoplastic resin such as vinyl chloride resin, vinylidene chloride resin, polyamide resin and the like are enumerated. Also, silver, nickel, copper and graphite are used as the conductive material. Chrome trioxide and dioxide, titanium dioxide, boron nitride, molybdenum disulfide, magnesium oxide, calcium carbonate, aluminum hydroxide, alumina, zinc flowers, clay, talk and the like are used as the semiconductor material and insulating material. As a result, a conductive composition, withstanding repetition of pressurization and having the characteristics in which its resistance value is smoothly reduced with the increase of pressuring force, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION ■ Industrial Application Field The present invention relates to a pressure-sensitive resistance change type conductive composition that can be applied to printing, painting, coating, etc. More specifically, it relates to a pressure-sensitive resistance change type conductive composition that can be applied to printing, painting, coating, etc. The present invention also relates to a pressure-sensitive resistance change type conductive composition in which the applied force and the resistance value are inversely proportional.

II. Prior Art and its Problems Materials having pressure-sensitive resistance change characteristics have been known for some time. For example, U.S. Patent No. 2044.080 discloses that Granulated Carbon
It has been disclosed that when a conductive material such as ) is pressed between electrodes, the resistance value of the material decreases. A similar example is U.S. Patent No. 3,806.
．． No. 471 also discloses the use of various semiconductor materials, the granular material being held together by a binder, and the use of spherical or granular materials to reduce hysteresis phenomena and prevent wear. It describes how to use it.

Further, US Pat. No. 3,710,050 discloses an invention in which 20 to 50% of rubber powder is added to conductive powder to bring out the pressure-sensitive conductivity of the powder.

In these examples, the powdered material is used as it is without using a dispersion medium such as rubber, so there are drawbacks such as the pressure-sensitive conductive material having to be housed in a special container. In the invention of the above-mentioned US Pat. No. 3,806,471, an idea was made to bind the powdery material with a binder, but the flexibility of the material was insufficient.

JP-A-56-108279 discloses an invention in which the thickness of this binder is reduced to 254 μm or less. Further, although an invention for trapping powder in the cell spaces of a foam is disclosed in US Pat. No. 2,305,717, even this invention cannot completely prevent the powder from falling off.

The problem of powder shedding can be solved, for example, in U.S. Patent No. 3,629.77.
As described in the specification of No. 4, this problem can be solved by covering the surface of the cells of the foam with a coating film containing conductive powder. However, the range of change in the resistance value of the pressure-sensitive conductor obtained by this technique is small. That is, the resistance value itself when released is not sufficiently high, and the ratio of the resistance value when released to the resistance value when pressurized is small, so it is not preferable as a switch element, for example.

In addition, pressure-sensitive conductive elastic compositions in which pressure-sensitive conductivity is imparted by blending special conductive powder with elastic materials such as silicone rubber are disclosed in Japanese Patent Publication No. 56-9137, etc.; It is extremely difficult to impart properties such as printing, painting, and coating to body compositions, and there are naturally limits to the precision, thinning, and weight reduction of switch elements and electronic components. There has been a desire for the emergence of a pressure-sensitive resistance change type conductive material that has excellent pressure sensitivity and properties such as printing, painting, and coating.

II+ OBJECTS OF THE INVENTION The object of the present invention is to show that the electrical resistance is significantly reduced by pressurization compared to the electrical resistance when not pressurized, and that the resistance smoothly decreases as the pressurizing force increases. It is an object of the present invention to provide a composition that provides a pressure-sensitive conductive material that provides a pressure-sensitive conductive material.

Another object of the present invention is to provide a pressure-sensitive resistance variable conductive composition that can be applied to printing, painting, coating, etc.

+V Structure of the Invention According to the first aspect of the present invention, the material contains an organic polymer material, a conductive material, a semiconductor material having an electrical conductivity of 1/100 or less of the conductive material, and an insulating material. A pressure-sensitive resistance variable conductive composition is provided.

Further, according to a second aspect of the present invention, the organic polymer material, an electrically conductive material, a semiconductor material having an electrical conductivity of 1/100 or less of the electrical conductivity of the electrically conductive material, an insulating material, and an organic solvent are contained. Provided is a pressure-sensitive resistance variable conductive composition characterized by the following characteristics.

Here, it is preferable that the organic polymer material is a vinyl chloride/vinyl acetate copolymer.

Further, it is preferable that the conductive material is graphite.

Further, the semiconductor material and the insulating material are one or more selected from chromium dioxide, titanium dioxide, boron nitride, molybdenum sulfide, magnesium oxide, calcium carbonate, aluminum hydroxide, alumina, zinc white, clay, and talc. Preferably, it is a substance consisting of.

Furthermore, it is preferable that the organic solvent is ethylene glycol monobutyl ether and/or acetic acid ethylene glycol mobutyl ether.

The configuration of the present invention will be explained in detail below.

Examples of organic polymeric materials used as binders in the present invention include thermosetting resins such as phenol resins, urea resins, melamine resins, furan resins, unsaturated polyester resins, epoxy resins, silicone resins, and polyurethane resins, and vinyl chloride. Resins, thermoplastic resins such as vinylidene chloride resin, vinyl acetate resin, acrylic resin, styrene resin, polyamide resin, cellulose derivatives such as nitrocellulose, acetylcellulose, and ethylcellulose, chlorinated rubber,
Examples include rubber derivatives such as hydrochloric acid rubber and silicone rubber, but any material that can be printed, painted, coated, etc. may be used. Vinyl chloride/vinyl acetate copolymers and modified products thereof The use is particularly preferred.

The conductive material used in the present invention may be any substance that has conductivity, such as silver, nickel, copper, and mica whose surface is coated with a conductive material, but graphite is especially preferred. Preferably,
Particularly preferred is flaky graphite having a size of about 6.0 μm.

Note that the electrical conductivity of graphite is anisotropic, with 10
It is in the range of 3 to 10°S-cm-'.

The semiconductor material and insulating material used in the present invention may be any material as long as it has an electrical conductivity of 1/100 or less of the conductive material, but preferably chromium sesquioxide, titanium dioxide, boron nitride, molybdenum disulfide,
Preferably, the material consists of 1 ffi or more selected from magnesium oxide, calcium carbonate, aluminum hydroxide, alumina, zinc white, clay, and talc.

The semiconductor material and the insulating material are j/
The reason why it is preferable to have an electrical conductivity of 100 or less is because if the electrical conductivity of the semiconductor material and the insulating material exceeds 1/100 of the electrical conductivity of the conductive material, pressure sensitivity will not be expressed. .

A specific combination of a conductive material, a semiconductor material having an electrical conductivity of 17100 or less, and an insulating material includes, for example, graphite (electrical conductivity of 103 to 103).
10°S-em-') and chromium sesquioxide (electrical conductivity 1
0-"S-am-' or less), graphite and titanium dioxide (electrical conductivity 10-5 to 10-"S・Cm"')
, graphite and boron nitride (electrical conductivity io-I48-
Cm-1), graphite and molybdenum disulfide (electrical conductivity 10-3 to 10-IQS-cm-'), graphite and magnesium oxide (electrical conductivity 10-'' S-am
-'), graphite and calcium carbonate (electrical conductivity 10-'' S -cm-'), graphite and aluminum hydroxide (electrical conductivity io-'s am-'), graphite and alumina (electrical conductivity 10-'' S -cm-') 15 cm
-I), graphite and zinc white (electrical conductivity 10-10
~ICM"S・Cm'-1), graphite and clay (
Electric conductivity: 10-''S-cm-'), graphite and talc (electrical conductivity: 10-''S.am-'), and the like.

Further, silver (electrical conductivity: 6.3 x 105 S cm-'), the above semiconductor material and insulating material, nickel (electric conductivity, 4 x 105 S cm-'), the above semiconductor material and insulating material, and copper (electric conductivity: 6. Oxl O5S-cm-
') and the above semiconductor materials and insulating materials, aluminum (
Mica (electrical conductivity 3.8x 105S-cm-') whose surface is coated with the semiconductor material and insulating material, conductive material (electrical conductivity 3x10S10S-') and the semiconductor material, insulating material, and conductive material. Certain ceramic whiskers (electrical conductivity 10-1 to 10-2 S-cm m-')
and the above-mentioned semiconductors and insulating materials.

The blending amounts of the above-mentioned organic polymer material, conductive material, and insulating material are not particularly limited, and can be freely determined as long as the composition obtained by blending these three materials exhibits a pressure-sensitive resistance change. It can be determined.

For example, if graphite is used as the conductive material and chromium sesquioxide and titanium dioxide are used as the insulating materials, the amounts of each are preferably in the following ranges.

When graphite is used as the conductive material and chromium monoxide is used as the insulating material, the amount of graphite blended is 40 to 180 parts by weight based on 100 parts by weight of the organic polymer material of the binder.
The weight part range is preferably from 45 to 110.
The range of overlapping parts is good.

If it is less than 40 parts by weight, the resistance change due to pressurization is small, and if it exceeds 180 parts by weight, the resistance change due to pressurization is too rapid.

Further, the blending amount of chromium sesquioxide is preferably in the range of 110 to 340 parts by weight based on 100 parts by weight of the organic polymer material (binder resin), and more preferably, the particle size is 0.
．． Granular chromium sesquioxide with a size of about 1 to 03 μm is
It is preferable to mix 325 parts by weight.

When the amount of chromium sesquioxide is less than 110 parts by weight,
This is because the resistance change due to pressurization is too rapid, and if it exceeds 340 parts by weight, the resistance change due to pressurization is small.

The total amount of graphite and chromium sesquioxide is preferably 280 to 390 parts by weight based on 100 parts by weight of the organic polymer material.

This is because if the amount is less than 280 parts by weight or more than 390 parts by weight, the variable pressure sensitive resistance type of the present invention cannot be achieved.

When graphite is used as a conductive material and titanium monoxide is used as an insulating material, an applied force of 0 to 3 kg changes from an insulating state to a conductive state. The horizontal axis is the logarithm of the applied force, and the vertical axis is the logarithm of the resistance value. In order to make the slope approximately -1 when 0 is removed, as shown later in Figures 7 to 9, the blending amount of graphite should be 30 to 30 M parts per 100 M parts of the organic polymer material (binder resin). A range of 160 parts by weight is preferred, and a range of 33 to 148 parts by weight is more preferred.

This is because if it is less than 30 parts by weight, the resistance change due to pressurization is small, and if it exceeds 160 parts by weight, the resistance change due to pressurization is too rapid.

The amount of titanium dioxide to be blended is in the range of 50 to 150 parts by weight per 100 parts by weight of the organic polymer material (binder resin), and more preferably the particle size is 0.1 to 0.3μ.
Something around m is good.

The total amount of graphite as a conductive material and titanium dioxide as an insulating material is preferably in the range of 170 to 220 parts by weight.

This is because if the amount is less than 170 parts by weight or more than 220 parts by weight, the variable pressure sensitive resistance type of the present invention cannot be achieved.

Note that by dissolving and dispersing the pressure-sensitive resistance change type conductive composition of the present invention described above in a suitable organic solvent, a composition excellent in printing, painting, coating, etc. can be obtained. It can be formed into a film by applying it onto a base material such as a film and evaporating the solvent.

Examples of the organic solvent used in the second aspect of the present invention include aliphatic hydrocarbons such as industrial gasoline and kerosene, aromatic petroleum naphthas such as low-boiling aromatic petroleum naphtha, and medium-boiling aromatic petroleum naphtha; Aromatic hydrocarbons such as penzole, doluol, quijirole, and solvent naphtha, terpene hydrocarbons such as turpentine oil, dipentene, and pine oil, and chlorinated hydrocarbons such as methylene chloride, trichlorethylene, perchlorethylene, orthodichlorohenzene. , nitrated hydrocarbons such as 2-nitropropane, aliphatic alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol methyl ether, Ether alcohols such as diethylene glycol monobutyl ether, ethers such as dioxane, acetic acid esters such as methyl acetate, ethyl acetate, isopropyl acetate, ethylene glycol monomethyl acetate, ethylene glycol monoethyl acetate, ethylene glycol monobutyl acetate, diethylene glycol monoethyl acetate Examples include ether esters such as.

Any usable solvent may be used, taking into account printing, painting, coating, etc. methods and the volatilization rate of the binder and solvent, but particularly preferred are ethylene glycol monobutyl ether and/or acetic acid ethylene glycol monobutyl ether. It is.

The pressure-sensitive resistance variable conductive composition of the first aspect of the present invention may be produced by any method, but one example is:
The composition of the second aspect of the present invention, in which graphite as a conductive material, chromium sesquioxide as an electrically insulating material, and an organic polymer binder are dissolved and dispersed in a suitable solvent, is applied onto a substrate such as a polyester film. It is obtained by evaporating the solvent at . The base material to be used is not limited to polyester film, but any material suitable for printing, painting, and coating may be used.

The pressure-sensitive resistance variable conductive composition of the present invention can be produced by changing the ratio of the conductive material and the semiconductor material or the insulating material.
Alternatively, by changing the type of the insulating material, it is possible to control the rate of change in resistance (sensitivity) to pressing force.

■　Example A more specific explanation will be given below with reference to Examples.

(A) Chromium sesquioxide was used as an insulating material, and the rate of change in resistance with respect to pressing force was investigated when the amount of chromium sesquioxide was varied.

(Example 1) 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 52 parts by weight of graphite (size approximately 6.0 μm), 370 parts by weight of chromium sesquioxide, 115 parts by weight of ethylene glycol monobutyl ether acetate, 485 parts by weight of ethylene glycol monobutyl ether After printing a printing ink composition consisting of parts by weight on a polyester film with a thickness of 188 μm,
In order to remove the solvent ethylene glycol monobutyl ether acetate and ethylene glycol monobutyl ether, a heating drying treatment was performed to obtain a pressure-sensitive resistance variable conductive composition having a pressure-sensitive conductor layer with a thickness of 70 μm. This composition was placed on a flat comb-like electrode, a parallel resistance of 50Ω and Ω was applied, and the properties were observed by repeatedly applying and removing pressure using a rod having a flat tip with a diameter of 10 mm.

The characteristics are shown in Figure 1. The upper curve of the hysteresis curve is the pressurization measurement, and the lower curve is the decompression measurement (hereinafter the first
6).

As shown in Figure 1, the relationship between pressurizing force and resistance is such that as soon as pressurization begins, the resistance drops smoothly and becomes conductive, and when pressurization is released, the original resistance immediately and smoothly returns. It returns to the value and shows an almost inversely proportional relationship between the pressurizing force and the resistance value.

Further, this state did not change even after repeated pressurization with a rod 1 million times.

It can be seen that the composition of the present invention has excellent durability against repeated pressurization and release.

(Example 2) Printing ink consisting of 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 41 parts by weight of graphite, 330 parts by weight of chromium sesquioxide, 90 parts by weight of ethylene glycol monobutyl ether acetate, and 510 parts by weight of ethylene glycol monobutyl ether. After printing the composition on a polyester film with a thickness of 188 μm, a heat drying treatment was performed to remove the solvent ethylene glycol monobutyl ether acetate and ethylene glycol monobutyl ether, resulting in a pressure-sensitive conductor layer with a thickness of 70 μm. A pressure-sensitive resistance variable conductive composition was obtained. This composition was placed on a flat comb-like electrode, a parallel resistance of 50Ω and Ω was applied, and the properties were observed by repeatedly applying and removing pressure using a rod having a flat tip with a diameter of 10 mm.

The characteristics are shown in Figure 2.

As shown in Figure 2, the relationship between pressurization force and resistance is such that as soon as pressurization begins, the resistance drops smoothly and becomes conductive, and when pressurization is released, it immediately and smoothly returns to its original resistance value. to return to.

(Example 3) Printing ink consisting of 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 180 parts by weight of graphite, 111 parts by weight of chromium sesquioxide, 420 parts by weight of ethylene glycol monobutyl ether acetate, and 180 parts by weight of ethylene glycol monobutyl ether. After printing the composition on a polyester film with a thickness of 188 μm, a heat drying treatment was performed to remove the solvent ethylene glycol monobutyl ether acetate and ethylene glycol monobutyl ether, resulting in a pressure-sensitive conductor layer with a thickness of 70 μm. A pressure-sensitive resistance variable conductive composition was obtained. This composition was placed on a flat comb-like electrode, a parallel resistance of 50Ω and Ω was applied, and the properties were observed by repeatedly applying and removing pressure using a rod with a flat tip having a diameter of 0 mm.

The characteristics are shown in Figure 3.

As shown in Figure 3, the relationship between pressurization force and resistance is such that as soon as pressurization begins, the resistance drops smoothly and becomes conductive, and when pressurization is released, the resistance returns immediately and smoothly to the original resistance value. to return to.

(Comparative Example 1) 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 227 parts by weight of graphite, 36 parts by weight of chromium sesquioxide, 540 parts by weight of ethylene glycol monobutyl ether acetate,
After printing a printing ink composition consisting of 60 parts by weight of ethylene glycol monobutyl ether on a 188 μm thick polyester film, a heat drying treatment was performed to remove the solvent ethylene glycol monobutyl ether acetate and ethylene glycol monobutyl ether. , a composition with a thickness of 70 μm was obtained. This composition was placed on a flat comb electrode, a parallel resistance of 50 Ω was added, and the diameter tomm
The characteristics were observed by repeatedly applying and releasing pressure using a rod with a flat tip. The characteristics are shown in Figure 4.

In this comparative example, as shown in Figure 4, the relationship between pressurizing force and resistance is that when pressurization starts, resistance drops and becomes conductive, and when pressurization is released, resistance increases and insulation is established. state. The sensitivity of the composition in this comparative example is slightly lower.
The reason for this is that the blending amounts of graphite and chromium sesquioxide deviate from the optimal blending range, and although it does not mean that pressure sensitivity is not exhibited, it is somewhat lacking in practicality.

(Comparative Example 2) A printing ink composition obtained by dissolving and mixing 100 parts by weight of vinyl chloride/vinyl acetate copolymer and 250 parts by weight of graphite in 600 parts by weight of ethylene glycol monobutyl ether acetate was applied on a polyester film with a thickness of 188 μm. After printing, a heating drying treatment was performed to remove ethylene glycol acetate sobutyl ether to obtain a composition with a dry film thickness of 70 μI. This composition was placed on a flat comb-like electrode, a parallel resistance of 50 Ω was added, and the diameter was 10 mm.
The characteristics were observed by repeatedly applying and releasing pressure using a rod with a flat tip.

The characteristics are shown in Figure 5.

In this comparative example, as is clear from the relationship graph of pressurized Kerr resistance in Figure 5, when pressurization starts, the resistance suddenly drops and becomes conductive, and when pressurization is released, the resistance value suddenly decreases. This results in an insulating state, and the variable pressure sensitive resistance type of the present invention cannot be realized.

(Comparative Example 3) A printing ink composition similar to that of Example 1 was prepared by dissolving and mixing 100 parts by weight of vinyl chloride/vinyl acetate copolymer and 400 parts by weight of chromium sesquioxide in 600 parts by weight of ethylene glycol monobutyl ether. dry film thickness 70u
A composition of m was prepared and the same properties as in Example 1 were observed.

The characteristics are shown in Figure 6.

In this comparative example, as is clear from the relationship graph of pressurized Kerr resistance in Figure 6, the resistance value does not change at all even when pressurization starts and remains in an insulated state, and even when pressurization is released, the resistance value remained in an insulating state without any change.

(B) Using titanium dioxide as an insulating material, the rate of change in resistance with respect to pressing force was investigated when the amount of titanium dioxide was varied.

(Example 4) A printing ink composition containing 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 50 parts by weight of graphite, 134 parts by weight of titanium dioxide, and 504 parts by weight of ethylene glycol monobutyl ether acetate was applied to a polyester film having a thickness of 188 μm. After printing on the film, a heat-drying treatment was performed to remove the solvent ethylene glycol monobutyl ether acetate, thereby obtaining a pressure-sensitive resistance variable conductive composition having a pressure-sensitive conductor layer with a thickness of 70 μm. . This composition was placed on a flat comb electrode, a parallel resistance of 50 Ω was added, and the diameter was 10 m.
Pressure was repeatedly applied and depressurized using a rod with a flat tip of m, and the characteristics were observed.

The characteristics of the pressure-sensitive resistance variable conductive composition in this example are as follows.
As shown in the figure. This figure 7 shows the relationship between pressurization force and resistance. When pressurization starts, the resistance immediately and smoothly decreases to a conductive state, and when pressurization is released, it immediately and smoothly returns to the original resistance value. The condition is shown.

Further, this state did not change even when the rod was repeatedly pressurized 1 million times, indicating that the composition of the present invention has excellent durability against repeated pressurization and release.

(Example 5) A printing ink composition containing 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 33 parts by weight of graphite, 146 parts by weight of titanium dioxide, and 497 parts by weight of ethylene glycol monobutyl ether acetate was applied to a polyester film with a thickness of 188 μm. After printing thereon, a heating drying process was performed to remove the solvent ethylene glycol monobutyl ether acetate, thereby obtaining a pressure-sensitive resistance variable conductive composition having a pressure-sensitive conductor layer with a thickness of 70 μm. This composition was placed on a flat comb electrode, a parallel resistance of 50 Ω was added, and the diameter was 10 m.
Pressure was repeatedly applied and depressurized using a rod with a flat tip of m, and the characteristics were observed.

The characteristics are shown in Figure 8.

As shown in Figure 8, the relationship between pressurizing force and resistance is such that as soon as pressurization starts, the resistance drops smoothly and becomes conductive, and when pressurization is released, it immediately and smoothly returns to its original resistance value. to return to.

(Example 6) The same method as in Example 1 was prepared from a printing ink composition containing 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 148 parts by weight of graphite, 58 parts by weight of titanium dioxide, and 547 parts by weight of ethylene glycol monobutyl ether acetate. A composition with a dry film thickness of 70 μm was prepared using the same method as in Example 1, and its properties were observed.

The characteristics are shown in Figure 9.

As shown in Figure 9, the relationship between pressurization force and resistance is such that as soon as pressurization begins, the resistance decreases smoothly and becomes conductive, and when pressurization is released, it immediately and smoothly returns to its original resistance value. to return to.

(Comparative Example 4) Example 1 from a printing ink composition containing 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 1 to 198 parts by weight of Graphi, 20 parts by weight of titanium dioxide, and 569 parts by weight of ethylene glycol monobutyl ether acetate. A composition having a dry film thickness of 70 μm was prepared in the same manner as in Example 1, and the same characteristics as in Example 1 were observed.

The characteristics are shown in FIG. FIG. 10 shows the relationship between the pressurizing force and the resistance. When pressurization starts, the resistance decreases and becomes conductive, and when pressurization is released, the resistance value increases and becomes insulated.

The sensitivity of the composition in this comparative example is slightly lower.

The reason for this is that the blending amounts of graphite and titanium dioxide are out of the optimum blending range, and this does not mean that pressure sensitivity does not develop, or that it is somewhat impractical.

(Comparative Example 5) A printing ink composition obtained by dissolving and mixing 100 parts by weight of vinyl chloride/vinyl acetate copolymer and 225 parts by weight of graphite in 580 parts by weight of ethylene glycol monobutyl ether acetate was applied on a polyester film with a thickness of 188 μm. After printing, heat drying is performed to remove ethylene glycol monobutyl ether acetate, resulting in a dry film thickness of 7.
A composition of 0 μm was obtained. This composition was placed on a flat comb-like electrode, a parallel resistance of 50Ω and Ω was applied, and the properties were observed by repeatedly applying and removing pressure using a rod having a flat tip with a diameter of 10 mm.

The characteristics are shown in FIG.

In this comparative example, as is clear from the relationship graph of pressurized Kerr resistance in Fig. 11, when pressurization starts, the resistance suddenly drops and becomes conductive, and when pressurization is released, the resistance value suddenly decreases. This results in an insulating state, and the pressure-sensitive resistance variable type of the present invention cannot be achieved.

(Comparative Example 6) Example 1 from a printing ink composition obtained by dissolving and mixing 100 parts by weight of vinyl chloride/vinyl acetate copolymer and 170 parts by weight of titanium dioxide in 480 parts by weight of ethylene glycol monobutyl ether acetate. Dry film thickness 70 using the same method as
A composition of μm was prepared and the same characteristics as in Example 1 were observed.

The characteristics are shown in FIG.

In this comparative example, as is clear from the relationship graph of pressurized Kerr resistance in Figure 12, the resistance value does not change at all even when pressurization starts and remains in an insulating state, and even when pressurization is released, the resistance value remains unchanged. The value changed but remained insulated.

(C) The rate of change in resistance with respect to pressing force was investigated when each substance shown in Table 1 was used as a semiconductor and an insulating material.

(Examples 7 to 16) Each substance having the electrical conductivity shown in Examples 7 to 16 in Table 1 was used as a semiconductor and insulating material, and 100 parts by weight of vinyl chloride/vinyl acetate copolymer, 57 parts by weight of graphite, and acetic acid were used. After printing a printing ink composition containing 500 parts by weight of ethylene glycol monobutyl ether and 124 parts by weight of the semiconductor and insulating material on a polyester film having a thickness of 188 μm, the solvent ethylene glycol monobutyl ether acetate is removed. For this purpose, heat treatment and drying treatment were performed to obtain a pressure-sensitive resistance variable conductive composition having a pressure-sensitive conductor layer with a thickness of 70 μm.

This composition was placed on a flat comb-like electrode, a parallel resistance of 50Ω and Ω was applied, and the properties were observed by repeatedly applying and removing pressure using a rod having a flat tip with a diameter of 10 mm.

The results are shown in Figures 13-15.

As shown in Figures 13 to 15, the relationship between pressurizing force and resistance is that as soon as pressurization begins, the resistance drops smoothly and becomes conductive, and when pressurization is released, it immediately and smoothly returns to its original state. The resistance value returns, and the pressurizing force and resistance value show an almost inversely proportional relationship.

Moreover, this state did not change even after repeated pressurization with a rod 1 million times.

It can be seen that the composition of the present invention has excellent durability against repeated pressurization and release.

(Comparative Example 7.8) As a comparative example, vinyl chloride, vinyl acetate copolymer 100
Ketchen Black EC, which is a carbon black having an electrical conductivity of more than 1/100 of the graphite shown in Comparative Example 7.8 in Table 1, based on 57 parts by weight of graphite and 500 parts by weight of ethylene glycol monobutyl ether acetate. After printing on a 188 μm thick polyester film, a printing ink composition obtained by mixing 124 parts by weight of 80% (manufactured by ZOchemie) or Palcan X C-72 (manufactured by Cabot), Heat treatment and drying treatment were performed to remove butyl ether, and a composition having a film thickness of 70 μm was obtained.

This composition was placed on a flat comb-like electrode, a parallel resistance of 50Ω and Ω was applied, and the properties were observed by repeatedly applying and removing pressure using a rod having a flat tip with a diameter of 10 mm.

The characteristics are shown in FIG.

As is clear from the relationship graph of pressurized Kerr resistance in Figure 16, when pressurization begins, the resistance suddenly drops and becomes conductive.
On the other hand, when the pressurization is released, the resistance value increases rapidly and becomes an insulating state, so that the pressure-sensitive resistance variable type of the present invention cannot be achieved.

Vl Effects of the Invention The pressure-sensitive resistance variable conductive composition of the present invention has the property of being able to withstand repeated pressurization and smoothly decreasing its resistance value as the pressurizing force increases, and can be used as a pressurizing force conversion element or as a variable resistor. Suitable for uses such as the body.

Further, the pressure-sensitive resistance variable conductive composition of the present invention is excellent in durability as a switch element operated by pressurization.

Further, the pressure-sensitive resistance variable conductive composition of the present invention exhibits an inversely proportional relationship between applied force and resistance value, and can be applied as various sensors such as applied force detectors.

Furthermore, the pressure-sensitive resistance variable conductive composition of the present invention can be used for printing,
It has application properties such as painting and coating, and can be printed into various shapes by using techniques such as screen printing.

The present invention is a keyboard switch, an automatic door switch,
Can be widely used as various pressure contact switches and other sensors.

[Brief explanation of the drawing]

The properties shown in FIGS. 1 to 16 were measured by adding a parallel resistance of 50 Ω to the composition. FIG. 1 is a graph showing the characteristics of the composition of Example 1. FIG. 2 is a graph showing the characteristics of the composition of Example 2. FIG. 3 is a graph showing the characteristics of the composition of Example 3. FIG. 4 is a graph showing the characteristics of the composition of Comparative Example 1. FIG. 5 is a graph showing the characteristics of the composition of Comparative Example 2. FIG. 6 is a graph showing the characteristics of the composition of Comparative Example 3. FIG. 7 is a graph showing the characteristics of the composition of Example 4. FIG. 8 is a graph showing the characteristics of the composition of Example 5. FIG. 9 is a graph showing the characteristics of the composition of Example 6. FIG. 10 is a graph showing the characteristics of the composition of Comparative Example 4. FIG. 11 is a graph showing the characteristics of the composition of Comparative Example 5. FIG. 12 is a graph showing the characteristics of the composition of Comparative Example 6. FIG. 13 is a graph showing the characteristics of the compositions of Examples 7 to 9. FIG. 14 is a graph showing the characteristics of the compositions of Examples 10 to 13. FIG. 15 is a graph showing the characteristics of the compositions of Examples 14-16. FIG. 16 is a graph showing the characteristics of the compositions of Comparative Examples 7 and 8. F I G, 1 Inner mouth, pressure, 77 (kc+) F I G, 2 Shiro force (kg) F I G. Calo, pressure (kg) F I G. Calo pressure (kg) FIG, 5 Noguchi pressure (kg) FI G, 6 Calo 7 pressure (kg) FIG, 8 Inner mouth■ Force (kg) FIG, 7 Calorie (kg) FIG, 9 Inner mouth Life force (kg) FIG, 10 Calo force (kg) FIG, 12 Force 0 Pressure (kg) FIG, 11 Calo force (kg) FIG, 13 Force 0 Pressure (kg) FIG. Force O Scale force (kg) F I G, 15 Karo 7 pressure (kg)

Claims (9)

[Claims] (1) A pressure-sensitive resistance change type conductive material comprising an organic polymer material, a conductive material, a semiconductor material having an electrical conductivity of 1/100 or less of the conductive material, and an insulating material. Composition. (2) The pressure-sensitive resistance variable conductive composition according to claim 1, wherein the organic polymer material is a vinyl chloride/vinyl acetate copolymer. (3) The pressure-sensitive resistance variable conductive composition according to claim 1 or 2, wherein the conductive material is graphite. (4) The semiconductor material and the insulating material are selected from chromium sesquioxide, titanium dioxide, boron nitride, molybdenum disulfide, magnesium oxide, calcium carbonate, aluminum hydroxide, alumina, zinc white, clay, and talc. Claim 1, which is a substance consisting of one or more types
The pressure-sensitive resistance variable conductive composition according to any one of Items 1 to 3. (5) A pressure-sensitive resistance change characterized by containing an organic polymer material, a conductive material, a semiconductor material having an electrical conductivity of 1/100 or less of the conductive material, an insulating material, and an organic solvent. type conductive composition. (6) The pressure-sensitive resistance variable conductive composition according to claim 5, wherein the organic polymer material is a vinyl chloride/vinyl acetate copolymer. (7) The pressure-sensitive resistance variable conductive composition according to claim 5 or 6, wherein the conductive material is graphite. (8) The semiconductor material and the insulating material are selected from chromium sesquioxide, titanium dioxide, boron nitride, molybdenum disulfide, magnesium oxide, calcium carbonate, aluminum hydroxide, alumina, zinc white, clay, and talc. Claim 5, which is a substance consisting of one or more types
The pressure-sensitive resistance variable conductive composition according to any one of Items 1 to 7. (9) The pressure-sensitive resistance variable conductive composition according to any one of claims 5 to 8, wherein the organic solvent is ethylene glycol monobutyl ether and/or acetic acid ethylene glycol monobutyl ether.