JPS6152182B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a conductive composition that can be advantageously used, for example, in the application of an electrically sensitive recording medium, and more particularly to a conductive composition that has synergistically significantly improved conductivity, low humidity dependence, stickiness resistance, and white color. The present invention relates to conductive compositions for electrically sensitive recording media having a combination of high performance and low cost. In this specification, an electrically sensitive recording medium refers to any recording medium that can perform recording in response to an electrical signal or that can perform recording in combination with electricity and other energy such as light, such as energized recording. It is defined as a concept that includes electrostatic recording media, electrostatic recording media, electrophotographic photosensitive recording media, etc. Regardless of the image forming mechanism used by these electrosensitive recording bodies, it is important from the standpoint of rapidly forming clear images that they have an appropriate conductive layer under the conditions of use. Conventionally, various materials have been used as conductive agents for imparting conductivity to these recording bodies, such as metal powder,
Carbon black, water-soluble or hygroscopic inorganic salts or organic salts, various surfactants, wetting agents such as polyhydric alcohols, polymer electrolytes, etc. are well known and actually used. However, all of these known conductive agents have drawbacks in one of the following respects, and are still not fully satisfactory. For example, conductive agents such as metal powder and carbon black are themselves good conductors and have the advantage of not being affected by humidity, but they generally have a specific color or opacity. This is a fatal flaw. In other words, it is most important for the recording medium to have excellent whiteness from the viewpoint of the sharpness and contrast of the image formed, and furthermore, the recording medium on which the image is formed can be processed by diazo copying method, electrophotographic copying method, etc. It is hoped that it can also be used as a manuscript for conventional copying methods. The metals and carbons mentioned above not only lack these properties;
It is still unsatisfactory in that the recording medium becomes heavy and relatively expensive. In addition, other conductive agents such as salts, activators, organic wetting agents, and polymer electrolytes all exhibit conductivity only in the presence of moisture, and therefore have various drawbacks. For example, in the case of electrolytic recording media that contain salts or the like as a conductive agent, it is necessary to use the recording media in a humidified state (wet state), and special consideration is required to store the recording media before use. In addition, wet recording tends to cause disadvantages such as smudging of images. Furthermore, electrostatic recording media and electrophotographic recording media equipped with a conductive layer made of a polymer electrolyte, such as a cationic conductive resin or anionic conductive resin, do not require the inconvenience of using the recording media in a humidified state. However, the effect of humidity on conductivity is still extremely large, and if a recording medium is left in a low-humidity atmosphere for a long time, the sharpness of the image may be lost due to a decrease in conductivity. On the other hand, in a high-humidity atmosphere, there is a disadvantage that the paper tends to stick to each other (tackiness) due to the fact that the polymer electrolyte is water-soluble. The present inventors particularly selected an aqueous emulsion type carboxyl group-containing polymer among various organic polymer binders, and added a proton conductive compound and an inorganic solid acid fine powder to this specific binder. It has been found that when a combination of the following is dispersed, a composition with outstanding electrical conductivity can be obtained. That is, according to the present invention, the proton conductive compound contains a proton conductive compound, an inorganic solid acid fine powder, and an aqueous emulsion type carboxyl group-containing polymer, and the proton conductive compound satisfies the following conditions: (i) carbon The ratio of number of atoms/number of nitrogen atoms (C/N) is 0
or (ii) the first-stage base dissociation constant (pKb, temperature 20℃)
an addition salt of an organic base and an inorganic or organic acid having a first stage acid dissociation constant (pKb, temperature 25°C) of 6.5 or less; Solid acid fine powder has a BET specific surface area of 50m ² /g
The above is a solid acid fine powder having adsorption properties, characterized in that the polymer is a copolymer or a graft polymer having an ethylenically unsaturated carboxylic acid or its acid anhydride as a polymer element. A conductive composition is provided. The conductive composition of the present invention is more conductive than a composition in which a proton conductive compound alone is dispersed in a binder or a composition in which an inorganic solid acid fine powder alone is dispersed in a binder. Not only is the conductivity increased synergistically, but the conductivity is significantly improved compared to using any other binder as the binder. Thus, the conductive composition of the present invention can be particularly advantageously used as a conductive substrate layer of the above-mentioned electrosensitive recording material and as a conductive recording layer. Furthermore, this conductive composition exhibits a certain level of conductivity even under low humidity conditions, and does not tend to stick even under high humidity conditions, offering an excellent combination of low humidity dependence and stickiness resistance. It has
In this way, the inconvenience of the humidification process and the like described above can be eliminated, and the recording medium can be advantageously used as a recording medium having good paper feeding characteristics and texture. Furthermore, the inorganic solid acid fine powder used in the present invention is generally a fine powder with excellent whiteness and pigment properties, and the proton conductive compound is also a solid with a significantly lower degree of coloration than ordinary organic bases. By using this proton conductive compound in combination with solid acid fine powder, the whiteness, smoothness, texture, etc. of the conductive layer can be significantly improved. Furthermore, the conductive layer composition of the present invention not only can be provided at a significantly lower cost than cationic conductive resins, etc., which are conventionally the best conductive agents, but also can make the conductive layer of a recording medium lighter or thinner. In conjunction with the possibility of stratification, significant economic advantages are achieved. Furthermore, while conventional conductive agents exhibit a property in which the conductivity decreases as the operating temperature rises, the conductive composition of the present invention exhibits properties that improve it, making it possible to perform recording operations under high temperature and low humidity conditions. It also has the advantage of being The invention will be explained in detail below. Proton conductive compound In the present invention, the proton conductive compound is
Defined as a solid electrolyte in which the mobile ions are protons. This solid electrolyte has protons as mobile ions even in an extremely dry state, and therefore exhibits ionic conductivity even in an extremely dry state, which is an important point different from ordinary solid electrolytes. be. The proton conductive compound is 1×10 ¹³ in an absolutely dry state.
It is desirable to have a volumetric resistance of Ω-cm or less, particularly 2.5×10 ¹² Ω-cm or less. From the viewpoint of easy availability and low electrical resistance, acid addition salts of organic bases are preferred, but other known proton conductive compounds can also be used as long as they satisfy the above conditions. The proton conductive compound comprising an acid addition salt of an organic base used in the present invention has significant advantages over low molecular weight or high molecular weight quaternary ammonium salts commonly used as conductive agents. That is, the mobile ions in the quaternary ammonium salt type conductive agent are:
In contrast to anions that exist as counter ions, the mobile ions in the conductive agent used in the present invention are protons (hydrogen ions), and the conductive agent used in the present invention has excellent ion mobility. In the former case, conductivity is obtained only by the presence of moisture;
In the latter case, the presence of water is not required to obtain conductivity. The organic base constituting the proton conductive compound includes primary, secondary or tertiary aliphatic, alicyclic,
Aromatic or heterocyclic amines, hydrazine or its derivatives, guanidine or its derivatives,
Examples include imines, and these bases may be low-molecular compounds or high-molecular compounds. Suitable examples of these organic bases are shown in Table 1 below, but the present invention is not limited to the exemplified organic bases.

【table】

[Table] The base used in the conductive agent of the present invention generally satisfies the following conditions: (i) the ratio of the number of carbon atoms to the number of nitrogen atoms (C/N) is in the range of 0 to 8, particularly 1 to 4; or (ii) the first stage base dissociation constant (pKb, temperature 20°C) is within the range of 0.3 to 8, particularly 2 to 6, and particularly preferably both. This is desirable. That is, in a preferred embodiment of the present invention, by selecting an organic base whose C/N value or pKb value is within the above range, the C/N value or pKb value is compared to the case where the C/N value or pKb value is outside the above range. As a result, the conductivity when used as a conductive agent can be significantly improved. The exact reason for this is unclear, but if C/N or pKb is smaller than the above range, the bond of the acid addition salt becomes too strong, making it difficult for protons to dissociate even in an electric field. In addition, if the C/N or pKb value is larger than the above range, the bond itself of the acid addition salt becomes weaker, making it difficult to form protons itself, and it is assumed that this is related to a decrease in proton concentration. be done. As the acid constituting the proton conductive compound of the present invention, any inorganic acid or organic acid can be used. However, from the viewpoint of the conductivity of the final conductive agent, the first stage acid dissociation constant (pKa , temperature at 25°C) is preferably in the range of 6.5 or less, particularly 5 or less. Suitable examples of inorganic acids are hydrohalic acids such as hydrochloric acid; sulfur oxyacids such as sulfuric acid, sulfurous acid; nitrogenous oxyacids such as nitric acid, nitrous acid; phosphorus oxyacids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid. suitable examples of organic acids are formic acid, acetic acid,
Trichloroacetic acid, crotonic acid, glycolic acid, salicylic acid, p-hydroxybenzoic acid, oxalic acid,
Carboxylic acids such as malonic acid, succinic acid, tartaric acid, azelaic acid, maleic acid, citric acid, pyromellitic acid, glutamic acid; Sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid; phosphonic acid, phosphinic acid, etc. can be mentioned. Preferred acids are, in order of importance, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, sulfonic acid. The acid addition salt of the organic base used may be a neutral salt, an acidic salt or a basic salt depending on the valency of the base and acid. These salts may be easily obtained by varying the reaction molar ratio of organic base and acid. Solid Acid Fine Powder In the present invention, it is extremely important to use a combination of an inorganic solid acid fine powder and the aforementioned proton conductive solid. For example, in a comparative experiment, the volume resistivity of fine silica gel powder as a solid acid (23℃, 50%RH or less) was
2.00×10 ⁸ Ω−cm, and the volume resistivity of guanidine sulfate as a proton-conducting solid is 6.69×
10 ⁷ Ω-cm. On the other hand, when guanidine sulfate is mixed homogeneously into this solid acid powder in an amount of 1% by weight (hereinafter, % and parts are based on weight unless otherwise specified), the volume resistivity becomes 5.31×10 ⁵ Ω. −
cm, which is approximately 380 times lower for solid acids and approximately 130 times lower for proton-conducting solids.
It is clear that this corresponds to a fold increase in conductivity. In the present invention, the inorganic solid acid fine powder is defined as the inorganic solid fine powder exhibiting the characteristics of Brønsted acid or Lewis acid. As such an inorganic solid acid, any natural, synthetic, by-product, recycled, or activated inorganic solid acid containing silicic acid, alumina, aluminosilicate, etc. can be used. A suitable example is: (A) Natural clay minerals or their activated products; montmorillonite group clay minerals such as bentonite, acid clay, fuller's earth, and subpentonite;
Kaolin group clay minerals such as kaolin, or activated clay minerals obtained by acid treatment of these minerals. (B) Amorphous silicic acid A dry process amorphous silicic acid fine powder available under the trade name Aerosil (Japan Aerosil). Wet-method amorphous silicic acid fine powder available under trade names such as Mizukasil (Mizusawa Chemical Industry), Tokusil (Tokuyama Soda), and Cyroid (Fuji Davison Chemical). (C) Activated alumina Amorphous alumina or alumina hydrate. (D) Composite oxides silica/alumina, silica/magnesia, silica/boria. (E) Zeolite Natural or synthetic zeolite, especially hydrogen ion or ammonium ion substituted zeolite. (F) Solid phosphoric acid type A fired product of a composition of silica or alumina and phosphoric acid. (G) Other inorganic chemicals Amorphous titanium dioxide, titanium phosphate, zircon phosphate. It is desirable that these inorganic solid acids be as fine a powder as possible from the viewpoint of being able to be uniformly dispersed in the binder and improving the conductivity and whiteness of the composition. Generally less than 20μ, especially
It is desirable to have a particle size of 10μ or less. Furthermore,
From the viewpoint of synergistically improving the conductivity of the conductive composition, the inorganic solid acids used in the present invention generally have adsorption properties, that is, those with a relatively large specific surface area, particularly those with a BET specific surface area of 50 m ² /g
In view of the above, more preferably 100 m ² /g or more. Particularly suitable solid acid fine powders for the purpose of the present invention include various clays, their acid-treated products, finely powdered silicic acid, and hydrogen ion type zeolites. Binder In the present invention, among various binders, it is particularly important to use an aqueous emulsion type carboxyl group-containing polymer from the viewpoint of synergistic improvement of conductivity. Conventionally, binders made of water-soluble polymers and emulsions of water-dispersible polymers have been widely used as binders for forming conductive agent layers. However, according to the present invention, when an aqueous emulsion type carboxyl group-containing polymer is used as a binder for dispersing the proton conductive compound and the inorganic solid acid fine powder, for example, water-soluble In the case of aqueous polymers (polyvinyl alcohol), the volume resistivity is 5.2 × 10 ⁸ Ω-cm, and in the case of other aqueous emulsions (polyvinyl acetate), the volume resistivity is 2.5 × 10 ⁸ Ω-cm. However, a significant increase in electrical conductivity results, with a volume resistivity of 6.1×10 ⁶ Ω-cm. The exact reason for this is unknown, but in the case of water-soluble polymers, a continuous film is formed surrounding the aforementioned dispersoids, and this film acts as a barrier against mobile ions (protons). It is difficult to form such a continuous film as a barrier with the binder used in the present invention, and the reason for this is that the carboxyl group contained acts as a charge carrier site and promotes the dissociation of protons. It seems to be. In the present invention, the carboxyl group-containing polymer preferably contains carboxyl groups so as to generally have an acid value of 1 to 30, particularly 5 to 20. That is, if the acid value is higher than the above range, the polymer has a greater tendency to become soluble in water, resulting in the disadvantages of water-soluble polymers. Furthermore, if the acid value is lower than the above range, a synergistic increase in conductivity may not be expected. Carboxyl group-containing polymers are produced by copolymerizing ethylenically unsaturated carboxylic acids or their acid anhydrides with other ethylenically unsaturated monomers, that is, by random copolymerization or block copolymerization, or by copolymerizing ethylenically unsaturated carboxylic acids or their acid anhydrides with other ethylenically unsaturated monomers, or by copolymerizing them with other ethylenically unsaturated monomers. It is produced by graft polymerization to a polymer of system unsaturated monomers. These copolymerizations or graft polymerizations can be carried out in the form of so-called emulsion polymerization to form an aqueous emulsion-type carboxyl group polymer, or a preformed copolymer or graft polymer can be reacted with, for example by ammonium saltation. It may be self-emulsified or post-emulsified using heat or a combination of a solvent and a surfactant to form an emulsion type polymer. Examples of ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, maleic anhydride, fumaric acid, itaconic acid, aconitic acid, atorbic acid, cinnamic acid, mangelic acid, citraconic acid, and mesaconic acid. Or two or more types can be mentioned. Monomers copolymerizable with these ethylenically unsaturated carboxylic acids include olefins such as ethylene and propylene; diolefins such as butadiene, isoprene, and chloroprene; and vinyl aromatics such as styrene, vinyltoluene, and α-methylstyrene. vinyl esters such as vinyl acetate, vinyl formate, and vinyl propionate; vinyl halide monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride; ethyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, and acrylic Acid-3
- Acrylic esters such as hydroxypropyl;
One or more of ethylenically unsaturated nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; nitrogen-containing vinyl compounds such as vinylpyridine, N-vinylpyrrolidone, vinyl carbazole, and acrylamide. The following combinations can be mentioned. Examples of emulsion type carbonyl-containing polymers suitable for the present invention are as follows. Acrylic acid-butadiene copolymer, acrylic acid-styrene-butadiene copolymer, maleic acid-methyl methacrylate-butadiene copolymer, crotonic acid-acrylonitrile-butadiene copolymer, methacrylic acid-ethylene-vinyl chloride copolymer , itaconic acid-styrene-butadiene copolymer, acrylic acid-vinyl acetate copolymer, methacrylic acid-ethyl acrylate-styrene copolymer, maleic acid-ethylene-vinyl acetate copolymer, methacrylic acid-ethyl acrylate Vinyl acetate copolymer, crotonic acid-vinyltoluene-butadiene copolymer, methacrylic acid-methyl methacrylate-styrene copolymer, acrylic acid-ethylene-vinyl acetate copolymer. Composition In the present invention, the proton conductive compound (A) and the inorganic solid acid fine powder (B) are most preferably A:B=0.5:100 to 100:100, particularly 2:100 to 80:100. It is desirable to use the combination in a weight ratio of 5:100 to 50:100. Proton conductive compound (A) and inorganic solid acid fine powder (B)
If the ratio between the two is outside the above-mentioned range, the degree of improvement in conductivity due to the synergistic effect of the two will be low. Furthermore, when the amount of compound (A) is greater than the above range, the conductivity of the composition may become saturated, the binding properties of the composition may be lost, or the coating film of this composition may tend to become sticky. This often occurs. On the other hand, if the amount of solid acid powder is larger than the above range, the absolute volume resistivity of the composition will become too high, or the humidity dependence of conductivity will become too large, which is not preferable for the purpose of the present invention. . The amount of the binder used varies depending on whether the conductive composition is used only as a conductive substrate layer or as a conductive recording layer of the electrically sensitive recording material, but generally speaking, Therefore, it is preferable to use the binder (C) in an amount of 10 to 500% by weight based on the total amount (A + B) of the proton conductive compound (A) and the inorganic solid acid fine powder (B). In the case of the electrically conductive substrate, amounts of 10 to 500% by weight are preferably used, and in the case of the subsequent electrically conductive recording layer, amounts of 20 to 100% by weight are preferably used. That is, when the amount of binder (C) used is less than the above range, the conductivity tends to be saturated and the binding properties of the composition tend to decrease significantly, while when it is more than the above range, Because the conductivity tends to decrease significantly and its humidity dependence also increases,
It is desirable to use it within the above range. Although generally not required, the conductive composition of the present invention may contain various conductive agents or auxiliary agents known per se, such as polyhydric alcohols, water-soluble inorganic salts, etc., if desired. Conductive Substrate Layer The conductive composition of the present invention can be advantageously used for preparing conductive substrates such as electrostatic recording paper and electrophotographic paper. This electrically conductive substrate is easily manufactured by coating or impregnating the composition of the present invention onto at least one surface of a paper substrate, or by incorporating it into the paper during manufacturing. The coating amount of the conductive composition varies depending on the degree of conductivity required, but it is generally desirable to be in the range of 3 to 50 g/m ² , particularly 5 to 30 g/m ² . The coating solution of the conductive composition of the present invention can be prepared, for example, by dissolving the proton conductive compound (A) in water, then uniformly dispersing the solid acid fine powder (C) in this solution, and finally dissolving the carboxyl group-containing polymer. It can be easily produced by adding and mixing an emulsion or latex. The solid content concentration of these coating solutions is determined from the viewpoint of workability.
It is preferably in the range of 10 to 60%, particularly 25 to 50%. A dielectric layer or a photoconductive layer, which is known per se, is provided on the conductive substrate to be used as electrostatic recording paper or electrophotographic paper. In this case, when coating the dielectric layer or photoconductor layer, in order to impart the necessary organic solvent resistance to the conductive layer, the water-soluble polymer is added in an amount that does not impair the essence of the conductive composition of the present invention. For example, it can be contained in the coating composition in an amount of 60% by weight or less based on the carboxyl group-containing polymer. Water-soluble polymers include various starches, cyanoethylated starch, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose (CMC), gum tragacanth, gum arabic, glue, casein, gelatin, sodium alginate, polyvinyl alcohol,
Examples include one or a combination of two or more of partially saponified polyvinyl acetate, partially acetalized polyvinyl alcohol, polyvinyl methyl ether, polyvinylpyrrolidone, polyacrylamide, water-soluble acrylic resin, and the like. In addition, for the same purpose, a crosslinking agent or an insolubilizer for reacting with carboxyl groups to insolubilize at least the surface of the coating film may be added in an amount that does not impair the essence of the conductive composition of the present invention, for example. It can be included in the coating composition or impregnated onto the coated surface after it has been formed in an amount of up to 10% by weight based on the carboxyl group polymer. Examples of such crosslinking agents or insolubilizing agents include melamine resin, urea resin, glyoxazal, glutaraldehyde, melamine formalin resin,
Examples include specially modified polyamide resins, formaldehyde, urea-formalin resins, triazo resins, alkyl ketene dimers, epoxy resins, polyvalent metal salt compounds, and their oxides (chromium, zirconium, antimony, aluminum, tin, zinc). Conductive Recording Layer The conductive composition of the present invention can also be advantageously used as a conductive recording layer of current-carrying recording paper. Current-carrying recording paper having the following coloring mechanism is known, and the conductive composition of the present invention can be used for any of these. (a) Introduction of foreign ions into the recording layer, (b) Discharge of ions at the electrode in contact with the recording layer, (c) Oxidation or reduction at the electrode surface in contact with the recording layer, (d) (e) Increase in the concentration of specific ions on the electrode surface (PH change); (e) Joule heat generated in the recording layer (thermal coloring). In the method based on the coloring mechanism (a) above, the metal needle as an anode is eluted into the conductive substrate in the form of cations due to an electrode reaction, and a coloring agent consisting of a chelating reagent contained in the conductive substrate is formed. What reacts to form a colored image of a chelate compound: A metal needle serving as an anode is eluted into a conductive substrate in the form of cations by an electrode reaction, and is reduced by a reducing agent contained in the conductive substrate. A substance that forms an image made of fine metal particles: A metal needle such as tellurium, which serves as a cathode, is eluted into a conductive substrate in the form of anions through an electrode reaction, and the resulting compound is secondarily decomposed and separated from the metal fine particles. It can be roughly divided into three mechanisms that form an image, and examples of color formers used in these mechanisms include those shown in Table 2 below.

【table】

[Table] Further examples of combinations other than those shown in Table 2 include the following. Metal coloring agent (chelating reagent) Ag: (polyvalent phenol compound) Galloyl gallic acid, chromotropic acid Fe: Tyrone, 2,2,2″-terpyridine nitroso R salt, hydroquinone, benzoylpyridine oxime Cu: Sodium ethylenediaminetetraacetate , rubeanic acid, sodium diethyldithiocarbamate, neocuproine Ni: sodium diethyldithiocarbamate, nitroso R salt. Suitable examples of the coloring mechanism of (b) above are as follows.

[Table] Anode Potassium iodide Iodine Starch Reactant Deep blue Further, suitable examples of the coloring mechanism described in (c) above are as follows.

[Table] Anode Leuco Crystal Crystal Bio Violet Lett dye Purple

[Table] 〓Reduction type〓
Cathode 2,3,5〓Tripheni Formazan dye Lutetrazonium Red chloride In addition to the above-mentioned oxidized coloring agents, there are many leuco dyes, such as leucoethyl nile blue (blue), leucomethylcaprylic blue (blue), and leukotoluin. Blue (purple) Leucodiphenylamine (purple) Leuco-N-methyldiphenylamine-p-sulfonic acid (purple red) Leucophenyl anthranilic acid (purple red) Methyl viologen (purple) Leucosafranin T (red) Leuco indigo Sulfonic acid (blue) Leuco enosafranin (red) Leuco methylene blue (blue) Leucodiphenylbenzidine (purple) Leuco auramine (yellow) Benzoyl leucomethylene blue (blue) Leuco eryoglucin A (yellow green → red) Leuco-p -Nitrodiphenylamine (purple) Leukodiphenylamine-O.O'-diphenylcarboxylic acid (blue-purple) can be used. In addition, as a reduced coloring agent, 2, 3, 5-
In addition to triphenyltetrazolium chloride, tetrazolium blue, tetrazolium purple,
Metal compounds such as tetrazolium violet, 2,5-diphenyl-3-(4-styrylphenyl)tetrazolium chloride, phosphotungstic acid, phosphomolybdic acid, and ammonium phosphomolybdate can be used. Furthermore, suitable examples of the color development mechanism described in (d) above are shown in Table 3 below.

[Table] Examples of diazonium salts include diazonium salts used in ordinary diazo copying methods, such as p
-N・N dimethylaminobenzenediazonium chloride zinc chloride double salt, 4-morpholinobenzenediazonium chloride zinc chloride double salt, p-N・N
Diethylamino-2,5-dimethoxybenzenediazonium chloride zinc chloride double salt and the like are used. Furthermore, in Table 3 above, among the latter color forming agent components, aromatic primary amines include amines used in the synthesis of ordinary diazonium compounds for copying, such as aniline, morpholine, N.N.
-Disubstituted paraphenylene diamine and the like are used in the form of hydrochloride and the like, and as coupling components, phenol derivatives, oxynaphthalene derivatives, active methylene group-containing compounds and the like are used. Furthermore, suitable examples of the color development mechanism described in (e) above include those shown in Table 4 below. 4th expression Color agent Color developer Leuco dye Acidic substance Metal salt of long chain fatty acid Phenol organic acid metal salt Metal sulfide, organic chelating agent Organic acid noble metal salt Aromatic organic reducing agent Higher fatty acid metal salt Zinc disubstituted dithiocarbamate Derivatives In this case, it is necessary that the solvent of the binder does not dissolve these color formers and color developers, and a combination of binder, color former, and color developer that satisfies this condition is selected. do. In the present invention, the above-mentioned color forming agent or further color developing agent is used in an amount sufficient to form an image of sufficient density;
That is, generally speaking, a proton conductive compound (A),
2 to 40%, especially 5 to 35%, based on the total amount of solid acid fine powder (B) and carboxyl group-containing polymer binder (C)
It is contained in the composition in an amount of . Furthermore, in order to stabilize the color former or color developer, stabilizers known per se, such as urea stabilizers such as thiourea or its alkyl derivatives; such as alkali metal chlorates or perchlorates, may be used. Oxidizing agents; acidifying agents such as formic acid, oxalic acid, hydrochloric acid, citric acid; or alkali metal or alkaline earth metal formates, acetates, carbonates, tartrates, bicarbonates, borates, phosphates; One or more alkaline buffers such as the following may be included. These compositions for forming a conductive recording layer have the following characteristics, except that they contain a color former or a color developer.
It can be produced by the same means as the coating composition for forming a conductive substrate described above. This coating composition can be coated on substrates such as paper substrates, conductively treated paper substrates, metal foils, metal laminated papers, metallized papers, films, etc. in a coating amount of 3 to 50 g/m ² , especially 5 to 25 g/m ^{2 .} It can be applied in large quantities. The conductive composition of the present invention can be particularly advantageously used in the reduced recording layer (C) containing a tetrazolium salt as a coloring agent. That is, in the composition of the present invention, since the mobile ions are protons, the color forming agent is extremely effectively reduced at the cathode, resulting in a recorded image with higher density and contrast than in conventional recording layers. It becomes possible to form. The conductive composition of the present invention has unexpectedly high conductivity compared to the case of solid acid fine powder or proton conductive compound alone, and the humidity dependence of this conductivity is similar to that of known inorganic salt conductivity. It has the remarkable advantage that it is significantly smaller than other conductive agents and organic conductive agents, exhibits high conductivity even under low humidity conditions, and shows virtually no tendency to stick even under high humidity conditions. . Moreover, this conductive composition has excellent whiteness and smoothness, and also has the advantage that an electrically sensitive recording material can be supplied at a relatively low cost. The invention is illustrated by the following example. Comparative example 1 Polyvinyl alcohol (Gohsenol GL-
05, manufactured by Nippon Gohsei Chemical Industry Co., Ltd.), polyvinyl acetate emulsion (Movinyl 550, Hoechst Synthesis), and emulsion of acrylic acid-styrene-butadiene copolymer (acid value: 12.5) were selected as binders, and kaolin (solid acid 30 parts of binder (as solid content) per 100 parts of fine powder), 30 parts of hexamethylenetetramine methanesulfonate (proton conductive compound)
Add an appropriate amount of water, and use a ball mill.
Grinding and mixing were carried out for 20 hours. This dispersion was applied onto a 50μ thick aluminum foil using a wire bar, and heated at 60℃ for 20 minutes.
Dry for a minute. After drying, it was left in an atmosphere at 14° C. and 54% relative humidity for 2 hours, and the volume resistivity was measured. The results are shown in Table 5.

[Table] The results show that the binder of the present invention has a lower volume resistivity than the former two. Example 1 Bentonite...10 parts Guanidine sulfate...0.1 part Maleic acid-styrene-butadiene copolymer emulsion (50% solution, acid value 7.3)...5 parts Water...80 parts The above composition Grinding and mixing were carried out in a ball mill for 20 hours. This dispersion was coated on double-sided art paper with a thickness of 80 μm using a wire bar and dried to obtain a conductive layer with a thickness of 10 μm. Separately, apply a similarly prepared dispersion for (a) that does not contain guanidine sulfate or (b) when a styrene-butadiene copolymer that does not contain maleic acid is used as a binder. A modified sample was also prepared. Table 6 shows the surface resistance of each sample.

[Table] Example 2 30 parts of acid clay, 5 parts of cyclohexylamine sulfate
18 parts of crotonic acid-vinyl acetate copolymer emulsion (50% solution, acid value 10), 4 parts of oxidized starch
and 100 parts of water were pulverized and mixed in a ball mill for 10 hours, and then 0.25 parts of melamine-formalin resin (Sumivez Resin 613, manufactured by Sumitomo Chemical) was added. After stirring thoroughly, apply 5 liters per side to both sides of high-quality paper.
The coating was applied and dried to a coating weight of g/m ² to produce conductive treated paper. This conductive treated paper is 8.9× at 20℃ and 40% relative humidity.
It showed 10 ⁷ Ω. Next, acrylic resin (Dianal LR-297, manufactured by Mitsubishi Rayon) was added to
% of Ritovon was added, the resulting mixture was pulverized and mixed, and the coating solution was applied and dried to a film thickness of approximately 10 μm on one side of the conductive treatment to produce electrostatic recording paper.
Linear density 6/mm on recording paper, recording speed 2m/sec,
After recording by applying a DC voltage of -600V with a pulse width of 20 μS, development is performed using a positive dry two-component developer (manufactured by Sanda Kogyo), heat-fixed, and the reflection density of the recorded image area is measured using a Sakura Microdensitometer PDM. -5
(manufactured by Konishiroku Photo Industry), it showed 1.5. Example 3 Amorphous silicic acid fine powder (manufactured by Mizusawa Chemical) 50 parts, 1.
6-diaminocyclohexane trichloroacetate 5
part, methacrylic acid-ethylene-vinyl chloride copolymer emulsion (45% solution, acid value 20.7) 20
1 part, 20 parts of 10% polyvinyl alcohol aqueous solution and water
A dispersion prepared by pulverizing and mixing 250 parts in the same manner was coated on both sides of high-quality paper at a concentration of 6 g/m ² and dried to produce conductive treated paper. The surface resistance of this paper was 6.3×10 ⁷ Ω at 16° C. and 44% relative humidity. Next, zinc oxide-sensitizing dye-binder (SAZEX4000 manufactured by Sakai Chemicals,
A photosensitive layer of bromophenol blue and acrylic resin Dianal FR-80) was coated to a thickness of 10 μm by a conventional method. When this photosensitive paper was copied using a dry type electronic copying machine 900-D manufactured by Sanda Kogyo, a sharp image with high contrast and no fogging could be obtained. Example 4 Kaolin...30 parts Titanium oxide (rutile type)...9 parts Tetramethylguanidine sulfate...12 parts Emulsion of methacrylic acid-methyl methacrylate-styrene copolymer (55% solution, acid value 6.6)
...20 parts Water ...120 parts The above composition was pulverized and mixed in a ball mill for 10 hours, 3 parts of benzoylleucomethylene blue, a leuco dye, was added, and the mixture was further pulverized and mixed for 5 hours. The thus prepared dispersion was applied onto aluminum vapor-deposited paper using a wire bar and dried. This produced recording paper has a conductive recording layer with a thickness of 15 μm, and was used as a dry electrolytic recording paper under the following conditions to record the reflection density.
A blue recording image of 0.72 (using a red filter) was obtained. Recording conditions: 12℃, 58.5%, recording speed 1.2m/sec, linear density 3.85
line/mm, stylus pressure 10g, recording voltage +200V. By the way, the binder and proton conductive solid of the present invention were removed, and a cationic conductive resin (ECR34, 33.5% aqueous solution, manufactured by Dow Chemical Company) was used instead.
In addition, 30 copies were added to the recording paper produced in the same manner, and the recorded image density was 0.40. Example 5 Instead of the leuco color table in Example 4, leucomalachite green and leuco crystal violet were used and recorded in the same manner, and the reflection density of each green color was
A recorded image with a reflection density of 0.68 and a blue-violet reflection density of 0.70 was obtained. Example 6 Hydrogen ion type zeolite 30 parts Titanium oxide (rutile type) 10 parts Diaminopropane sulfate 12 parts Acrylic acid-ethylene-vinyl acetate copolymer emulsion (45% solution, acid value 14.6) 28 parts Water 110 parts The above composition was pulverized and mixed in a ball mill for 15 hours, 3 parts of 2,3,5-triphenyltetrazolium chloride was added, and further pulverized and mixed for 30 minutes.
This dispersion was applied onto a carbon-treated conductive polyester film having a thickness of 80 μm and having a surface resistance of 3×10 ³ Ω and was dried. The thickness of this conductive recording layer is 16
µ, dry electrolysis recording was performed in the same manner as in Example 4, but the recording voltage was +200V, and the reflection density was 0.57.
A red recorded image (using a green filter) was obtained. Example 7 In place of the tetrazolium salt in Example 6, tetrazolium blue and neotetrazolium chloride were used to similarly obtain blue (reflection density 0.52 red filter used) and purple (reflection density 0.48 no filter) recorded images.

Claims (1)

[Scope of Claims] 1 Comprising a proton conductive compound, an inorganic solid acid fine powder, and an aqueous emulsion type carboxyl group-containing polymer, the proton conductive compound comprising:
The following conditions are met: (i) The ratio of the number of carbon atoms/the number of nitrogen atoms (C/N) is 0.
or (ii) first stage base dissociation constant (pKb, temperature 20℃)
is in the range of 0.3 to 8, and an addition salt of an organic base and an inorganic or organic acid with a first stage acid dissociation constant (pKb, temperature 25°C) of 6.5 or less, Inorganic solid acid fine powder has a BET specific surface area of 50m ² /g
The above is a solid acid fine powder having adsorption properties, characterized in that the polymer is a copolymer or a graft polymer having an ethylenically unsaturated carboxylic acid or its acid anhydride as a polymer element. conductive composition. 2 The proton conductive compound meets the following conditions: (i) The ratio of the number of carbon atoms/the number of nitrogen atoms (C/N) is 1.
(ii) Base dissociation constant of the first stage (pKb, temperature 20℃)
is in the range of 2 to 6, and a patent claim is an addition salt of an organic base that satisfies at least one of the following: and an inorganic or organic acid having a first-stage acid dissociation constant (pKb, temperature 25°C) of 5 or less The conductive composition according to item 1. 3 The proton conductive compound is 1×10 ¹³ in an absolutely dry state.
The conductive composition according to claim 1, which is a conductive compound exhibiting an electrical resistance of Ω-cm or less. 4. The conductive composition according to claim 1, wherein the inorganic solid acid fine powder is a clay mineral, an acid-treated product thereof, an amorphous silicic acid fine powder, or a hydrogen ion type zeolite. 5. The conductive composition according to claim 1, wherein the aqueous emulsion type carboxyl group-containing polymer has an acid value of 1 to 30. 6 The proton conductive compound (A) and the inorganic solid acid fine powder (B) in a weight ratio of A:B=0.5:100 to 100:100, and the aqueous emulsion type carboxyl group-containing polymer (C) is a proton conductive compound (A)
per total amount (A+B) of and inorganic solid acid fine powder (B)
A conductive composition according to claim 1, characterized in that it is present in an amount of 10 to 500% by weight. 7 (A) proton conductive compound, (B) inorganic solid acid fine powder, (C) aqueous emulsion type carboxyl group-containing polymer, and (D) introduction of different ions, ion discharge,
The proton conductive compound contains a color former or a color developer capable of developing color by oxidation-reduction, PH change, or Juur heat, and the proton conductive compound satisfies the following conditions: (i) the ratio of the number of carbon atoms/the number of nitrogen atoms ( C/N) is 0
or (ii) first stage base dissociation constant (pKb, temperature 20℃)
is in the range of 0.3 to 8, and an addition salt of an organic base and an inorganic or organic acid with a first stage acid dissociation constant (pKb, temperature 25°C) of 6.5 or less; Inorganic solid acid fine powder has a BET specific surface area of 50m ² /g
The above is a solid acid fine powder having adsorption properties, the polymer is a copolymer or a graft polymer having an ethylenically unsaturated carboxylic acid or its acid anhydride as a polymer element, and the above-mentioned The weight of each component of (A) to (D) is A:B=0.5:100 to 100:100 (A+B)=100:10 to 100:500 (A+B+C):D=100:2 to 100:40 1. A composition for an electrically conductive recording layer, characterized in that the composition is present in a ratio of 1 to 3.