JPH08141388A - Aqueous liquid with dispersed fine particle, production thereof and solid composition obtained from said aqueous liquid - Google Patents

Abstract

PURPOSE: To obtain a stable aqueous liquid having fine particles uniformly dispersed and a dry composition thereof by a method wherein a metal compound solution is added to an aqueous medium containing a water-soluble or water- dispersible polymer to precipitate the fine particles of a metal or metal compound in a specific size and in a specific proportion. CONSTITUTION: A aqueous liquid and its dry composition are obtained which have dispersed in an aqueous medium containing a water-soluble or water- dispersible polymer fine particles of a metal or metal compound having a diameter of 1-1000nm and containing solid components in an amount of 0.001-12wt.% based on its total weight and a total solid concentration of at least 1wt.%. As the water-soluble polymer is used natural starch, its derivative, pullulan, synthetic polyvinyl-pyrolidone, polyvinyl alcohol of the like. As the water- dispersible polymer is used a thermosetting phenol resin or epoxy resin, or thermoplastic polyethylene or polypropylene. As the fine particles of the metal or metal compound is used gold, silver, copper, zinc or silver oxide.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous liquid containing a water-soluble polymer and / or a water-dispersible polymer in which metal fine particles and / or metal compound fine particles having a diameter of 1 to 1000 nm are uniformly dispersed, a process for producing the same, and a dry composition thereof. It is about things.

[0002]

2. Description of the Related Art Heretofore, in order to mix an additive with a polymer, a kneader of roll type, Banbury type, screw type, rotor type or the like has been generally used. When the diameter of the additive fine particles is 1 to 1000 nm, the interparticle cohesive force is so strong that it was impossible to disperse them in the polymer quite uniformly. In addition, attempts have been made to add fine particles dispersed in water in order to add fine particles to water-based paints, etc.
An aqueous paint in which fine particles of 000 nm are uniformly dispersed has not been obtained. In many cases, the pH of the aqueous liquid phase in which the polymer is dispersed is adjusted to be weakly acidic for stabilization, and even if metal fine particles / metal compound aqueous colloid is added to this, it is usually the surface of metal fine particles or metal compound fine particles. Has a negative surface charge, the dispersion system becomes unstable due to heteroaggregation, and the medium aggregates and sediments, so that a uniform metal fine particle or metal compound fine particle dispersed polymer cannot be finally obtained.

[0003]

As a result of various studies on methods for uniformly dispersing fine particles in a polymer, when the polymer is a water-soluble or water-dispersible polymer and the fine particles are a metal or a metal compound, the following method is used. It was found that it is possible to obtain a composition in which fine particles are uniformly dispersed.

[0004]

That is, the present invention provides a water-based polymer containing a water-soluble polymer and / or a water-dispersible polymer with a diameter of 1 to 1000 nm and a total solid content of 0.001.
It is an aqueous liquid in which the metal particles and / or metal compound particles in an amount of ˜12% by weight are uniformly dispersed and the total solid component concentration is 1% by weight or more.
Further, the present invention is the above-mentioned method for producing an aqueous liquid, characterized in that a metal compound solution is added to an aqueous medium containing a water-soluble polymer and / or a water-dispersible polymer to deposit corresponding metal fine particles and / or metal compound fine particles. Further, the present invention is a solid composition obtained by drying the above aqueous liquid. If the fine particles are pre-formed, the problem of cohesion is inevitable when mixed with the polymer, but the polymer is dissolved or dispersed in water and its viscosity is 0.8-2000c.
It was found that fine particles having good dispersibility can be obtained by precipitating metal fine particles and / or metal compound fine particles by utilizing chemical reaction or physical phenomenon in an aqueous medium of P. It is considered that this is because the surface of the dissolved polymer or the dispersed polymer becomes nuclei for the precipitation of fine particles, and the growth of particles independently proceeds on a large number of nuclei. At this time, it is necessary to add the metal compound solution to the aqueous liquid containing the polymer, and even if the dispersion liquid of the metal fine particles and / or the metal compound fine particles is added to the aqueous liquid containing the polymer, fine particles having good dispersibility cannot be obtained. When a chemical reaction is used, the viscosity of the medium in which the polymer is dissolved or dispersed in water is 0.8 to 2000.
Although it is possible to use cP, the viscosity is preferably 0.8 to 600 cP, more preferably 0.8 to 100 cP. This is because a lower viscosity enables a uniform reaction throughout the medium. Note that various concentration steps may be performed after the fine particles are prepared in order to increase the ratio of the total solid content.

The water-soluble polymers used in the present invention include natural water-soluble polymers and / or synthetic water-soluble polymers. Natural water-soluble polymers include starch and its derivatives, pullulan, water-soluble cellulose derivatives, alginic acid,
There are guar gum, gum arabic, tragacanth gum and gelatin. Examples of the water-soluble cellulose derivative include carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and the like.

As the synthetic water-soluble polymer, polyvinylpyrrolidone, polyvinyl alcohol, polyethylene oxide, polyvinyl ether, polyacrylamide, sodium polyacrylate, polyethylene glycol, water-soluble acrylic resin, water-soluble epoxy resin, water-soluble polyester resin, water-soluble urethane There is resin. Natural water-soluble polymers and / or synthetic water-soluble polymers may be used in combination.

The water-dispersible polymers used in the present invention include thermosetting polymers and thermoplastic polymers. As thermosetting polymer, phenol resin, epoxy resin,
Unsaturated polyester resin, alkyd resin, urea resin,
Examples include melamine resin, urethane resin, silicone resin and diallyl phthalate resin.

As the thermoplastic polymer, polyethylene,
Polyolefins such as polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, etc., and polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polymethylmethacrylate, polyacrylamide, polyether, polyacrylonitrile, polyfluoroethylene, polyester, polycarbonate, nylon, polyimide , Polyamideimide, polysulfone, polyvinyl acetal, polyvinyl alcohol, polycarbonate, ABS resin, AS resin and the like. Further, these thermoplastic polymers and thermosetting polymers may be used in combination, or a copolymerized polymer having the main chain of the above polymer as a constituent element may be used.

The water-dispersible polymer has a diameter of 1-1000.
nm is desirable, and more preferably 1 to 800 nm. As a chemical reaction for depositing fine particles, a reduction reaction is used when depositing fine metal particles, and as a reaction for depositing fine metal compound particles, a sol-gel method or a coprecipitation method is used. High temperature and pressure conditions may also be used to bring the reaction to completion quickly. As a physical method for depositing the fine particles, the temperature dependence of the solubility of the metal compound is used. That is, when the temperature coefficient of solubility of a metal compound in an aqueous medium composed of a water-soluble polymer and / or a water-dispersible polymer is positive, the metal compound is saturated and dissolved at a high temperature to gradually lower the temperature of the metal compound. Compound fine particles can be prepared.

The metal fine particles or metal compound fine particles to be uniformly dispersed in a water-soluble polymer or a water-dispersible polymer include photochromic materials, antibacterial materials, antifungal materials, antialgae materials, magnetic materials, nonlinear optical materials, pigments, catalysts, A conductive material or the like can be used, and the diameter thereof is preferably 1 to 1000 nm, more preferably 1 to 600 nm, and particularly preferably 1 to 10 in order to stably maintain the dispersed state.
It is 0 nm. Photochromic materials include silver halide, and magnetic materials include barium ferrite and γ-
Ferrite, magnetite, manganese ferrite, etc., non-linear optical materials include gold, silver, silver halide, pigments include gold, silver, catalysts include platinum, palladium, rhodium, iridium, etc. Examples of the material include tin oxide, indium tin oxide, silver and gold.
In particular, gold, silver, copper, zinc oxide, titanium dioxide, silver halide, silver oxide, magnesium oxide, cuprous oxide, cuprous oxide, etc. are used as the antibacterial material, and silver is used as the fungicide and algae control material. , Silver halide, silver oxide, copper, cuprous oxide, cuprous oxide.

The metal fine particles thus obtained and /
Alternatively, an aqueous liquid containing a polymer in which metal compound fine particles are uniformly dispersed can be removed into water by means of spray drying or the like to obtain a solid composition. This composition is one in which metal fine particles and / or metal compound fine particles are uniformly dispersed on a polymer contained in an aqueous liquid. Examples of the present invention will be shown below.

[0012]

【Example】

Example 1 Commercially available fluororesin aqueous emulsion water repellent (manufactured by Meisei Chemical Co., Ltd., Asahi Guard AG-471, solid content concentration 2.3 wt)
%, Average particle size 120 nm) 50 ml was put in a 100 ml eggplant flask, and silver nitrate 8.50 mg (0.05 mm) dissolved in 45 ml of distilled water.
ol, AgNO ₃ , special grade reagent) were added and mixed at room temperature. The viscosity of the dispersion liquid at this time was 11 cP. After that, sodium borohydride (NaBH ₄ , special grade reagent) 7.57 mg (0.2 mmo
5 ml of distilled water in which l) was dissolved was added to obtain an aqueous emulsion of a fluorine-repellent agent containing Ag fine particles of 0.5 mmol / l and having a uniform light yellow color. The concentration of fine silver particles in all the solid components was 0.47% by weight. The silver fine particle-containing fluorine water repellent aqueous emulsion was dried on a carbon thin film and observed with a transmission electron microscope. The dispersed state of silver fine particles is good, the average particle size is 4.2 nm,
The coefficient of variation was 40.5%. Here, the variation coefficient is a value obtained by dividing the average value of the particle diameters by the standard deviation of the particle diameters. This aqueous fluorine-repellent agent emulsion containing fine silver particles was stable at room temperature for 3 months or longer, and no change was observed in the dispersed state.

100 ml of the aqueous emulsion was placed in a beaker, and a commercially available cotton cloth (10 cm square) was immersed in the beaker for 5 minutes and stirred. The cotton cloth was taken out of the aqueous emulsion, air-dried, and then heat-treated at 120 ° C. for 10 minutes and 170 ° C. for 30 seconds to obtain a silver fine particle-containing water repellent cotton cloth. When the cotton cloth was subjected to surface analysis with an X-ray microanalyzer, silver fine particles were uniformly distributed on the surface of the cotton cloth. A 5 cm square test piece was obtained from the cotton cloth and subjected to an antibacterial test. Escherichia coli and Staphylococcus aureus were suspended in a sterilized phosphate buffer solution to prepare a bacterial concentration of about 10 ⁵ / ml. After dropping 1 ml of each bacterial solution on the test piece, it was stored at 25 ° C. for 18 hours. After 18 hours, the test bacterial solution on the test piece was washed out with 10 ml of SCDLP medium, and the number of viable bacteria in the washed out solution was measured by the pour plate culture method (35 ° C, 2 days) using SCDLP agar medium. The results are shown in Table 1. Excellent antibacterial properties were confirmed.

Comparative Example 1 45 ml of distilled water in which 8.50 mg (0.05 mmol, AgNO ₃ , special grade reagent) of silver nitrate was dissolved was placed in a 100 ml eggplant flask, and sodium borohydride (NaBH ₄ , special grade reagent) 7.57 mg (0.2 mmol)
5 ml of distilled water in which was dissolved was added to obtain a light yellow uniform silver fine particle aqueous dispersion of Ag 1.0 mmol / l. 50 ml of the fluororesin aqueous emulsion water repellent used in Example 1 was mixed with this,
It was stirred. Immediately after mixing, it was light yellow and uniform, but after 5 hours, the upper part of the eggplant flask became colorless and transparent, and yellow agglomerates were formed in the lower part.

Subsequently, the cotton cloth was dipped and stirred in the same manner as in Example 1. The cotton cloth was taken out of the aqueous emulsion, air-dried, and then heat-treated at 120 ° C. for 10 minutes and 170 ° C. for 30 seconds to obtain a silver fine particle-containing water repellent cotton cloth. When the cotton cloth was subjected to surface analysis with an X-ray microanalyzer, the distribution of silver fine particles on the surface of the cotton cloth was non-uniform because silver aggregates were locally present. A 5 cm square test piece was obtained from the cotton cloth, and an antibacterial test was conducted in the same manner as in Example 1. The results are shown in Table 1. The antibacterial property was poor.

[0016]

[Table 1]

Example 2 8.50 mg of silver nitrate (0.05 mmol, AgNO ₃ , special grade reagent) 2 g of polyvinyl alcohol (reagent for atomic absorption spectrometry) and 95 ml of distilled water
Dissolved in. The viscosity was 3 cP. Put this in a 100 ml eggplant-shaped flask, add 5 ml of distilled water in which 7.57 mg (0.2 mmol) of sodium borohydride (NaBH ₄ , special grade reagent) was dissolved, and add a pale yellow uniform silver fine particle-containing poly (Ag 0.5 mmol / l). A vinyl alcohol aqueous solution was obtained. The silver fine particle concentration in all the solid components was 0.27% by weight. The aqueous solution of polyvinyl alcohol containing silver fine particles was dried on a carbon thin film and observed with a transmission electron microscope. The fine silver particles were in a good dispersion state, the average particle size was 6.2 nm, and the coefficient of variation was 47.2%. This aqueous solution of polyvinyl alcohol containing fine silver particles was stable at room temperature for 3 months or longer and showed no change in the dispersed state. The aqueous solution was spray-dried to obtain a polyvinyl alcohol powder containing fine silver particles. When the powder was subjected to surface analysis with an X-ray microanalyzer, silver fine particles were uniformly distributed in the polyvinyl alcohol powder.

An antibacterial test of the powder was carried out. Escherichia coli and Staphylococcus aureus were suspended in 0.9% saline to prepare a bacterial concentration of about 10 ⁴ / ml. 100 mg of the powder was added to 100 ml of the test bacterial solution and stirred at 30 ° C for 30 minutes. After 30 minutes, a certain amount of the test solution was sampled, and the number of colonies generated after culturing in L agar medium at 30 ° C. for 2 days was compared with the number of colonies of a control containing no silver to determine the viable cell ratio. Table 2 shows the results
It was shown to. Excellent antibacterial properties were confirmed.

Comparative Example 2 45 ml of distilled water in which 8.50 mg (0.05 mmol, AgNO ₃ , special grade reagent) of silver nitrate was dissolved was placed in a 100 ml eggplant flask, and sodium borohydride (NaBH ₄ , special grade reagent) 7.57 mg (0.2 mmol)
5 ml of distilled water in which was dissolved was added to obtain a light yellow uniform silver fine particle aqueous dispersion of Ag 1.0 mmol / l. To this, 2 g of polyvinyl alcohol dissolved in 50 ml of distilled water used in Example 2 was mixed and stirred. Immediately after mixing, it was light yellow and uniform, but 5
After a lapse of time, the upper portion of the eggplant flask became colorless and transparent, and a yellowish brown aggregate was formed at the lower portion. The aqueous solution was spray-dried to obtain a polyvinyl alcohol powder containing fine silver particles. When the powder was analyzed for silver with an X-ray microanalyzer, the distribution of silver particles in the polyvinyl alcohol powder was non-uniform because silver aggregates were locally present. An antibacterial test of the powder was conducted in the same manner as in Example 2, and the results are shown in Table 2. The viable cell ratio was high and almost no antibacterial activity was observed.

[0020]

[Table 2]

Example 3 Polyethylene glycol 5 g (primary reagent, average molecular weight 200
00) was dissolved in 100 ml of distilled water. This viscosity was 1.5 cP. Put this in a 100 ml eggplant flask with a reflux device,
Heated to ° C. Tetrapropyl titanate 14.2mg
_{(0.05mmol, Ti (OC 3 H} 7) 4, special grade reagent) was added, Ti (O
H) ₄ 0.5 mmol / l white uniform polyethylene hydroxide fine particle-containing polyethylene glycol aqueous solution was obtained. By heating this aqueous liquid under reflux, an aqueous polyethylene glycol solution containing titanium oxide fine particles was obtained. The concentration of fine particles in all solid components was 0.12% by weight. This titanium oxide fine particle-containing polyethylene glycol aqueous solution is dried on a carbon thin film,
It was observed with a transmission electron microscope. The dispersion state of titanium oxide fine particles is good, the average particle size is 5.2 nm, and the coefficient of variation is 14.5.
%Met. This polyethylene glycol fine particle-containing polyethylene glycol aqueous solution was stable at room temperature for 3 months or longer, and no change was observed in the dispersed state. A filter paper was sprayed onto the aqueous solution and dried at room temperature to obtain a test piece having a diameter of 4 cm. This is JIS Z 291
It was subjected to a fungus resistance test using 1-compliant 8 kinds of mixed bacteria. Four
No mold was found on the test piece after a week.

COMPARATIVE EXAMPLE 3 100 ml eggplant flask with a reflux condenser kept at 90 ° C. Distilled water 50 ml
Tetrapropyl titanate 14.2 mg (0.05 mmol, Ti (OC ₃
H _{7) 4,} special grade reagent) was added to obtain a Ti (OH) ₄ white homogenous titanium hydroxide fine particle aqueous dispersion of 1.0 mmol / l. Next, this dispersion was heated under reflux to obtain a titanium oxide fine particle aqueous dispersion. Polyethylene glycol
50g distilled water in which 5g (first-class reagent, average molecular weight 20000) was dissolved
ml was mixed and stirred. Immediately after mixing, it was white and uniform,
After 7 hours, the upper part of the eggplant flask became colorless and transparent, and white aggregates were formed in the lower part. A mold resistance test was conducted in the same manner as in Example 3. Spraying of the mixture onto the filter paper could not be done uniformly. After 4 weeks, mold development was observed in an area of 1/3 or more of the test piece.

Example 4 Vinyl acetate-ethylene copolymer resin emulsion (hex
Togo Gosei Co., Ltd., Movinyl 181E, concentration 55% by weight, average
Particle size 400nm) 20g, ferric chloride hexahydrate (FeCl ₃・ 6H
₂O, special grade reagent) 3.00 g (11.1 mmol) and ferrous sulfate heptahydrate
Thing (FeSO_Four・ 7H₂O, primary reagent) 1.54 g (5.53 mmol)
Dissolve in 130 ml of distilled water and 2.5 g of sodium hydroxide.
50 ml of distilled water was added. The viscosity at this time was 800 cP.
After heating and refluxing for 5 minutes, magnetite (Fe₃O_Four) Fine particles
Obtained blended vinyl acetate-ethylene copolymer resin emulsion
Was. Then, the distilled water is thoroughly washed by the gradient method,
pH of 5 and black uniform Fe₃O_FourThe concentration of 27.65 mmol / l
Vinyl acetate-ethylene copolymer resin containing particulates
An emulsion was obtained. The concentration of fine particles in all solid components is 10.
It was 42% by weight. Dry the emulsion on a carbon thin film
Then, it was observed with a transmission electron microscope. Magnetite fine
The dispersed state of the particles is good, the average particle size is 420 nm, and the coefficient of variation is
Was 10.2%. The emulsion should be stored at room temperature for 3 months
As described above, the dispersion was stable and no change was observed.

[0024]

According to the present invention, metal fine particles and / or metal compound fine particles having a diameter of 1 to 1000 nm can be uniformly dispersed in an aqueous medium containing a water-soluble polymer and / or a water-dispersible polymer. Since a solid composition can be obtained by drying, the photochromic material,
It has been shown that it can be applied to antibacterial materials, antifungal materials, algae materials, magnetic materials, nonlinear optical materials, pigments, catalysts, conductive materials, etc.

Claims (14)

[Claims] 1. Metal fine particles and / or metal compound fine particles having a diameter of 1 to 1000 nm and a content of 0.001 to 12% by weight in all solid components are homogeneous in an aqueous medium containing a water-soluble polymer and / or a water-dispersible polymer. An aqueous liquid in which fine particles are dispersed, characterized in that the total solid component concentration is 1% by weight or more. 2. The metal fine particles and / or metal compound fine particles are selected from the group consisting of gold, silver, copper, zinc, silver oxide, magnesium oxide, zinc oxide, titanium dioxide, cuprous oxide, cuprous oxide, and magnetite fine particles. The aqueous liquid according to claim 1, which is at least one selected from the group consisting of: 3. The aqueous liquid according to claim 1, wherein the water-soluble polymer is at least one selected from the group consisting of natural water-soluble polymers and / or synthetic water-soluble polymers. 4. The natural water-soluble polymer is at least one selected from the group consisting of starch and its derivatives, pullulan, water-soluble cellulose derivatives, alginic acid, guar gum, gum arabic, tragacanth gum and gelatin. Aqueous liquid. 5. The synthetic water-soluble polymer is polyvinylpyrrolidone, polyvinyl alcohol, polyethylene oxide, polyvinyl ether, polyacrylamide, sodium polyacrylate, polyethylene glycol, water-soluble acrylic resin, water-soluble epoxy resin, water-soluble polyester resin, water-soluble. The aqueous liquid according to claim 3, which is at least one selected from the group consisting of urethane resins. 6. The water-dispersible polymer has a diameter of 1 to 100.
The aqueous liquid according to claim 1, which has a thickness of 0 nm. 7. The aqueous liquid according to claim 6, wherein the water-dispersible polymer is a thermosetting polymer and / or a thermoplastic polymer. 8. A metal compound solution is added to an aqueous medium containing a water-soluble polymer and / or a water-dispersible polymer to precipitate corresponding metal fine particles and / or metal compound fine particles. A method for producing an aqueous liquid in which the fine particles according to any one of the above are dispersed. 9. The method for producing an aqueous liquid according to claim 8, wherein the viscosity of the aqueous medium containing the water-soluble polymer and / or the water-dispersible polymer is 0.8 to 2000 cP. 10. The method for producing an aqueous liquid according to claim 8, wherein the metal fine particles and / or the metal compound fine particles are precipitated from the corresponding metal compound solution by a chemical reaction or a physical method. 11. The chemical reaction is a reduction reaction.
The method for producing an aqueous liquid according to 1. 12. The method for producing an aqueous liquid according to claim 10, wherein the chemical reaction is a sol-gel method or a coprecipitation method. 13. The method for producing an aqueous liquid according to claim 10, wherein the physical method utilizes a change in solubility of the metal compound with temperature. 14. A solid composition obtained by drying the aqueous liquid according to claim 1.