JPH04293970A - Composite particle of ceramic with conductive polymer and its preparation - Google Patents

Abstract

PURPOSE:To prepare the title particles which can be stably dispersed in an org. material impart electric conductivity thereto by forming a specific coating layer at least on the surfaces of ceramic particles. CONSTITUTION:A reaction producing a conductive polymer (e.g. polypyrrole) is conducted in the presence of ceramic particles (e.g. silica particles) to form a coating layer consisting of the polymer at least on the surfaces of the particles.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ceramic-conductive polymer composite fine particles comprising ceramic fine particles and a conductive polymer.

0002

BACKGROUND OF THE INVENTION Ceramic fine particles are currently widely used in all industrial fields and are one of the important raw materials for which applied research and development is progressing. Specific fields of application include coating agents for paper products such as wrapping paper, copying paper, and photosensitive paper, binders for ceramics, refractories, and heat insulating materials, raw materials for catalysts, fillers and reinforcing agents for plastics, rubber, and elastomers, and adhesives. Examples include additives for latex coatings and paints, additives for waxes and brighteners, and additives for fibers and glass fibers.

That is, by blending ceramic particles with organic materials such as polymers, they can improve the material properties such as strength and impact resistance, and improve the organic materials' properties such as wear resistance and friction properties. New functional materials can be created by imparting missing properties, or by imparting optical or electromagnetic properties that do not exist in organic materials. In such cases, the state of dispersion of ceramic fine particles in the organic material is closely related to the physical properties of the material.

[0004] Many techniques have been developed up to now as methods for controlling the dispersion state of ceramic particles in an organic material reinforced with ceramic particles. There are methods using inorganic grafting, methods using coupling agents, etc. Coupling agents include silane-based, titanate-based, aluminum-based,
There are zirconium type, zircoaluminate type, etc.

On the other hand, with the computerization and electronicization of the living environment in factories, research institutes, offices, stores, transportation systems, public facilities, homes, etc., all materials fields are becoming increasingly susceptible to antistatic properties, conductivity, electromagnetic shielding properties, etc. There is a need to control electromagnetic properties. Organic materials, such as polymers, are generally electrically insulating. Therefore, the conventional methods used to achieve the goal of creating organic materials whose electrical properties can be controlled include the use of conductive fillers. These include filling organic materials, applying conductive paint to molded products, and vapor deposition of conductive materials such as metals and metal oxides.

[0006]

[Problem to be Solved by the Invention] When a conductive filler is filled into an organic material containing ceramic fine particles for the purpose of imparting conductivity to the organic material, the amount of the organic material that is the matrix becomes relatively small. Organic material properties may not be expressed. Furthermore, when considering the material and process costs associated with filling conductive filler, the final cost is too high and there are many fields in which it is difficult to apply. This also applies to the application of conductive paint, the vapor deposition of conductive materials such as metals and metal oxides, and the like.

Therefore, an object of the present invention is to provide an economically superior technique for simultaneously imparting dispersion stability and conductivity to ceramic fine particles in an organic material.

[0008]

[Means for Solving the Problems] The present inventors have discovered that dispersion stability and conductivity of ceramic fine particles in an organic material can be imparted at the same time by coating at least the surface of the ceramic fine particles with a conductive polymer. ,
This led to the present invention, and its gist is as follows:
A ceramic-conductive polymer composite fine particle characterized in that a coating layer of a conductive polymer is provided on at least the surface of the ceramic fine particle, and a conductive polymer production reaction is carried out on at least the surface in the presence of the ceramic fine particle. The present invention provides a method for producing ceramic-conductive polymer composite fine particles having the above-described structure.

The ceramic-conductive polymer composite fine particles of the present invention are ceramic fine particles whose at least the surface is coated with a conductive polymer. There are no particular restrictions on the ceramic fine particles used in the present invention, but
For example, SiO2, TiO2, ZnO, Al2O3
, metal or semiconductor oxides such as ferrite, and nitrides such as aluminum nitride.

[0010] Also, conductive polymer refers to a substance that exhibits conductivity due to the electronic state of the polymer itself, and typical examples include π-electron conjugated polymers such as polypyrrole, polyfuran, polythiophene, and polyaniline. can be mentioned. It was confirmed that ceramic fine particles coated with such a conductive polymer have not only conductivity but also an affinity for organic materials.

[0011] The method for producing ceramic-conductive polymer composite fine particles of the present invention involves performing a reaction for producing a conductive polymer in the presence of ceramic fine particles. Specifically, the surface of the ceramic fine particles is made conductive. This method is used as a site for polymerization reactions of polymers, and according to this method, it is possible to impart conductivity to ceramic fine particles as well as affinity for organic materials.

There are no particular limitations on the manufacturing conditions for the ceramic-conductive polymer composite fine particles of the present invention, but the dispersion stability of the ceramic fine particles in the reaction system is maintained during the conductive polymer production reaction. It is necessary to devise ways to do so. In other words, although it depends on the type and variety of ceramic fine particles, in general, colloidal ceramic fine particles have a pH value of
Since the dispersion stability changes depending on the salt concentration, etc., it is necessary to conduct the reaction in a stable region.

[0013] Methods for producing conductive polymers generally include electrochemical methods and chemical methods, and either method can be used in the present invention.

The mechanism by which conductive polymers are formed on the surface of ceramic fine particles is currently not clear;
When negative ions exist on the surface of the ceramic particles, they act as dopants for the conductive polymer, and on the other hand, when positive ions exist, they adsorb negative ions in the system and remove these negative ions. It is presumed that the stabilization of the polymerization reaction and subsequent stabilization of the surface coating state is achieved because the ions act as dopants on the conductive polymer.

[0015]

[Examples] The present invention will be explained below with reference to specific examples.

[Example 1] Silica fine particle dispersion 12 prepared by diluting colloidal silica “trademark CATALOID-SI-80P” manufactured by Catalysts & Chemicals Co., Ltd. 5 times with ion-exchanged water.
Add 4 mL of Wako Pure Chemical Industries, Ltd. 0.1N silver nitrate aqueous solution to 5 ml.
After dropping and mixing 0 ml, 40 ml of a 0.1 M pyrrole aqueous solution was added dropwise while stirring to obtain a black-gray dispersion. This dispersion was mixed with ion-exchanged water for about 1 hour.
After diluting it 00 times and dropping it onto a mesh for transmission electron microscopy observation and drying it thoroughly, it was observed with a transmission electron microscope JEM-100CXII manufactured by JEOL Ltd., and it appeared that polypyrrole was composited with silica fine particles. was confirmed.

[Example 2] The same method as in Example 1 above was carried out except that a 0.05M ammonium persulfate aqueous solution was used in place of the 0.1N silver nitrate aqueous solution.
As in Example 1, it was confirmed that polypyrrole was composited into silica fine particles.

[Example 3] Except that 0.1M ferric chloride aqueous solution was used instead of 0.1N silver nitrate aqueous solution,
When the same method as in Example 1 was carried out, it was confirmed that polypyrrole was composited with silica fine particles in the same manner as in Example 1.

[Example 4] Colloidal silica “trademark CATALOID-SI-80P” manufactured by Catalysts & Chemicals Co., Ltd.
．． Add 40ml of 0.1M pyrrole aqueous solution to 125ml of silica fine particle dispersion diluted 5 times with 0.1N potassium chloride aqueous solution.
ml dropwise and mixed as an electrolyte, platinum electrodes were used as the cathode and anode, and a potentiostat was used to generate 1 mA.
Electrolysis was carried out for 4 hours while stirring the solution under constant current conditions of cm-2. This electrolyte was diluted approximately 100 times with ion-exchanged water, dropped onto a mesh for transmission electron microscopy, and dried thoroughly.
When observed at 100CMII, it was confirmed that polypyrrole was composited into silica fine particles.

[Example 5] 1 ml of the magnetic fluid “Marpo Magna FW-40” manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., which is a dispersion of ferrite particles, was diluted 100 times with ion-exchanged water, and 0.1 M chloride was diluted with ion-exchanged water. After dropping and mixing 40 ml of ferric aqueous solution, 40 ml of 0.1M pyrrole aqueous solution was added while stirring.
0 ml was added dropwise and mixed. When the mixture was stirred and mixed overnight at room temperature and observed under an electron microscope in the same manner as in Example 1, it was confirmed that polypyrrole was composited with ferrite fine particles.

[Example 6] 40 ml of a 0.05M ammonium persulfate aqueous solution was added dropwise to a solution prepared by diluting 10 ml of alumina sol “Cataroid-AS-3” manufactured by Catalysts & Chemicals Co., Ltd. 10 times with ion-exchanged water. When 40 ml of a 0.1 M pyrrole aqueous solution was added dropwise and mixed with stirring, a black-gray dispersion was obtained. When this dispersion was observed using an electron microscope in the same manner as in Example 1,
It was confirmed that polypyrrole was composited with alumina fine particles.

[0022]

[Effects of the Invention] As is clear from the detailed explanation above, the ceramic-conductive polymer composite fine particles of the present invention have a surface coated with a conductive polymer, so they are stable against organic materials. It can be dispersed and at the same time impart conductivity.

Claims (2)

[Claims] 1. Ceramic-conductive polymer composite fine particles, characterized in that a coating layer of a conductive polymer is provided on at least the surface of the ceramic fine particles. 2. A ceramic, characterized in that a conductive polymer formation reaction is carried out on at least the surface of the ceramic fine particles in the presence of the ceramic fine particles, thereby forming a coating layer of the conductive polymer on at least the surface of the ceramic fine particles. Method for manufacturing conductive polymer composite particles.