JPS6287242A - Stable metal oxide sol composition - Google Patents

Abstract

PURPOSE:To prevent the growth of particles due to flocculation of said particles by incorporating a chelating agent or a metal chelate to the sol contg. the condensate of a metal oxide or a metal hydroxide having <=0.1mum mean particle size. CONSTITUTION:The titled sol is prepared by using the particles which are made of the condensate of the metal oxide or the metal hydroxide having <=0.1mum mean particle size. The stable metal oxide type sol composition is obtd. by incorporating the chelating agent and/or the metal chelate to the obtd. sol. A beta-dicarbonyl compd. is used to the chelating agent, and a beta- dicarbonylmetal chelate is preferably used as the metal chelate. The molar content of the chelated molecule contd. in the chelating agent and/or the metal chelating is preferably 0.05-2.0 times of the metallic element which constitutes the prescribed particles.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a novel gold-containing oxide-based sol composition. Specifically, the present invention provides a metal oxide sol in which the particles constituting the sol are fine particles of a metal oxide or metal hydroxide condensate, and the average diameter thereof is 0.1 μm or less, and a chelating agent and/or a metal chelate are added to the sol. The object of the present invention is to provide a stable metal oxide-based sol composition comprising the following.

Forming uniform metal oxide or metal hydroxide thin films on substrates such as plastics, ceramics, and metals can be used for optical-related devices, storage materials, piezoelectric materials, sensors, antistatic materials, corrosion-resistant, wear-resistant materials, etc. It is expected to have a wide range of applications, and some have even been put into practical use.

In addition, fine particles of oxides or hydroxides have a high surface activity, and as an easily sinterable film-forming material, an inexpensive manufacturing method is required, especially in the ceramics field.

(Prior Art) It is known that cationic metal ions or oxymetal monomers form chelate complexes with chelating agents. For example, tin acetylacetonate, titanium oxalate acetylacetonate (Japanese Unexamined Patent Publication No. 56-26896), methyl stearoyl acetone bis(isooctanoyl) zirconate (Japanese Unexamined Patent Publication No. 59-196368), etc. It is raised. However, these are compounds whose units are metal monomers, and chelating agents require an equivalent amount or more of the chelating agent to the metal, or they are not contained in the form of solid particles, so they are coated in a thin film. After that, when a metal hydroxide or oxide film is formed through drying and firing steps, there are problems such as large shrinkage and easy cracking.

On the other hand, organic metal compounds, particularly metal alkoxides, have been frequently used as raw materials for metal oxide thin films because of their relatively high raw material purity. However, metal alkoxides are very easily hydrolyzed, and there are problems in that delicate humidity adjustment is required when forming a thin film and that the pot life of the liquid is short. As a method to avoid these problems, a method has been proposed in which a chelating agent or a metal chelate is added to an alcoholic solution of a metal alkoxide or its polymer (in this case, an alkoxy group remains at the terminal).

For example, JP-A-59-195504, JP-A-59-
213602, JP-A-59-213603, JP-A-59-196368@, and JP-A-60-6299. All of these use organometallic compounds as the metal oxide source, so alkoxy groups that have not undergone hydrolysis remain bonded to metal atoms, and chelating agents are used as hydrolysis resistance improvers. be.

Furthermore, in the specification of Japanese Patent Publication No. 59-46268, it is stated that β-diketones, which are β-dicarbonyl compounds, are added to the surface of composite oxide particles of calcium oxide, magnesium oxide, or zinc oxide and aluminum oxide, titanium dioxide, or silicon dioxide. A heat stabilizer for vinyl chloride resin has been proposed in which a complex of The particle size of the oxide is relatively large in the range of 0.5 to 50 μm, and the inorganic oxide or inorganic hydroxide fine particles targeted by the present invention (average particle size of 0.1 μm or less) ) as an anti-aggregation agent for β-
There is no suggestion regarding the use of dicarbonyl compounds.

In addition, the specification of Japanese Patent Publication No. 60-4552 shows that acetylacetone is effective as an antioxidant for copper, silver, or copper alloy powder, but the present invention does not apply to particle components and β-dicarbonyl compounds. They differ in the purpose of use of acetylacetone, which is a type of acetylacetone.

Conventionally, as a method to prevent gelation and aggregation of a dispersion of inorganic oxide or inorganic hydroxide condensate fine particles (hereinafter referred to as metal oxide sol) in a liquid, the absolute value of the zeta potential of the particle surface has been calculated. A stabilization method that uses electrical repulsion to increase the size is known.

Specifically, this objective can be achieved to some extent by adjusting the pH or by making metal compounds with different valences exist on the particle surface. The stabilized metal oxide-based sol composition disclosed in the present invention is novel and completely different from these conventionally known methods.

(Problem to be solved by the invention) As the particle size becomes smaller in a metal oxide-based sol, the number of particles and the particle surface area at the same concentration increase.As a result, it is difficult to maintain a stable particle dispersion using conventional techniques alone. It's getting difficult.

The present invention provides a metal oxide sol which is stable over time, thermally and chemically at high concentrations even in the case of fine particles having a particle diameter of 0.1 μm or less, particularly about several tens of angstroms. Thus, the object of the present invention is to provide a metal oxide sol composition that is stable for thin film production, and to prevent particle growth due to agglomeration when using the oxide or hydroxide fine particles in the sol as a raw material for producing easily sinterable ceramics. It is an object of the present invention to provide a sol composition that can prevent this, and to obtain highly dispersible fine particles from this sol.

(Means for Solving the Problems) The present invention was discovered as a result of intensive studies to overcome the drawbacks of conventional techniques in the industrial production and use of sols containing various metal elements and sols with small average particle diameters. The characteristics of this sol are that the particles constituting the sol are fine particles of a metal oxide or metal hydroxide condensate, and the average diameter thereof is 0.1 μm or less, and a chelating agent,
In particular, the objective is to obtain a stable metal oxide-based sol composition in which a β-dicarbonyl compound and/or a metal chelate coexist.

(Function) The chelating agents used in the present invention include oxyphenols such as catechol and pyrogallol, amino alcohols such as jetanolamine and triethanolamine, oxyacids such as glycolic acid, lactic acid, and hydroxyacrylic acid. Their esters such as methyl, ethyl, and hydroxyethyl, oxydialdehydes such as glycolaldehyde, amino acids such as glycine and alanine, and β-diketones such as acetylacetone, benzoylacetone, stearoyl acetone, stearoyl/benzoylmethane, and dibenzoylmethane. β-ketonic acids such as acetoacetic acid, propionyl acetic acid, benzoylacetic acid and their methyl, ethyl, n-propyl, 1so-
Examples include esters such as propyl, n-butyl, and tert-butyl, but preferably β-dicarbonyl compounds such as β-diketones or β-keto acids and their esters are used. Metal chelates include aluminum, barium, beryllium, calcium, cadmium, cobalt, chromium, copper, iron, gallium, hafnium, mercury, indium, iridium, potassium, lithium, magnesium, manganese, molybdenum, sodium, nickel, lead, and platinum. , palladium, rhodium, ruthenium, scandium, silicon, tin, strontium,
Examples include chelates of thorium, titanium, thallium, tantalum, tungsten, uranium, vanadium, yttrium, zinc, zirconium, lanthanoid metals, or partial oxides thereof with the above chelating agent.

On the other hand, the metal components in the particles constituting the metal oxide sol are single or composite oxides or hydroxide condensates of the above-mentioned metals, preferably titanium, zirconium, cerium, vanadium, niobium, The main component is at least one metal selected from the group of tantalum, aluminum, gallium, indium, tin, manganese, nickel, cobalt, and iron.

The amount of the chelating agent and/or the chelating agent molecules in the metal chelate may be less than or equal to the amount of metal atoms in the particles, preferably in the range of 0.05 to 2.0 times. If it is less than 0.05 times, the effect is small; 2.
Even if it is added in excess of 0 times, the quantitative effect is small and it is not economical.

The method for producing the metal oxide sol applicable to the present invention is not particularly limited, and any known method may be used. For example, inorganic salts such as metal chlorides, nitrates, and sulfates, and organic acid salts such as oxalic acid and acetic acid are converted into metal oxides or metal hydroxide condensates by alkaline hydrolysis, thermal hydrolysis, ion exchange, etc. in water. Alternatively, an organometallic compound such as a metal alkoxide or its alcohol solution may be added to water to completely hydrolyze the alkoxide to form a hydroxide condensate, or metal fine particles may be hydrolyzed to form a hydroxide. A method of making it into a sol is also possible. or,
Other specific examples include using one or more oxygen-containing organic compounds as a dispersion medium during alkaline hydrolysis, thermal hydrolysis, or ion exchange of metal salts, or using a mixed solution of these with water. A stable metal oxide-based sol can also be produced by In this case, compared to the case where only an aqueous dispersion medium is used, a stable metal oxide-based sol can be produced even if the amount of counter ions of inorganic salts such as chlorine ions, nitrate ions, sulfate ions, etc. This is particularly advantageous when producing a sol. For example, in the case of titania sol, the stability in an aqueous solvent system has a close relationship with the titania concentration and the type and amount of the chelating agent. That is, with a TiO2 equivalent concentration of 10%, acetylacetone (number of moles)/Ti (number of atoms) = 0.6, and a sol composition of chlorine ion (number of atoms)/Ti (number of atoms) = 0.05 or less, 3 months have passed. The viscosity increases afterward, but when methanol, which is a type of oxygen-containing organic compound, is used as the dispersion medium, with the same TlO2 equivalent concentration and the same type and amount of chelating agent, chlorine ion (atomic fi) /T
Even if a sol with i (number of atoms)=0.005 is produced, the sol remains stable even after 6 months have passed. Such a tendency was also observed in other metal oxide-based sols, and the effect of the oxygen-containing organic compound could be demonstrated. Further, the higher the proportion of the oxygen-containing organic compound in the dispersion medium, the more effective it is, but the effect will be significant if it is 10% or more, preferably 20% or more, based on the total ff1ffl. This coexistence effect of the oxygen-containing organic compound is observed during the formation of the sol by the above-mentioned hydrolysis, after the formation, or during fractional addition. Examples of the oxygen-containing organic compound include alcohols such as methanol, ethanol, propatool, and butanol;
Ketones such as acetone and methyl ethyl ketone, ethers such as methyl ethyl ether and dioxane, and esters such as methyl formate and methyl acetate can be suitably used.

In the method for manufacturing the metal oxide sol described above, there are no restrictions on the timing and method of adding the chelating agent and/or metal chelate, and as described above, the addition may be performed before, during, during, or separately added to the fine particles. The effect of preventing agglomeration of the fine particles can be exhibited by finally allowing the fine particles to coexist with the chelating agent and/or the metal chelate.

The metal oxide sol stabilization mechanism of the β-dicarbonyl compound, which is a particularly preferred chelating agent in the present invention, is not fully elucidated, but it is localized on the surface of oxide or hydroxide fine particles. It is thought that the coordination bond of the β-dicarbonyl compound to a site with a positive surface charge makes the particle surface non-hydrophilic and prevents aggregation caused by collisions between particles. Agglomeration here refers to particles (metallic element-oxygen in the present invention) that are called linear inorganic polymers in which bonds are connected in a chain, irregularly shaped substances that are bonded three-dimensionally, and mixtures thereof. This refers to particle growth due to dehydration condensation between particles and billy formation due to hydrogen bonding between particles.

On the other hand, as an effective dispersion medium which is a practical aspect of the present invention,
When at least one type of oxygen-containing organic compound is used, the amount of chlorine ions, nitrate ions, sulfate ions, etc., which are counterions of inorganic salts, can be further reduced compared to when the metal oxide sol is only an aqueous dispersion medium. The present inventors believe that the reason why the sol exists stably even when the temperature is increased is as follows. In other words, it is said that as counterions decrease, the surface charge of sol particles decreases, and the repulsive force due to electrostatic force decreases, making it easier for sol aggregation to occur. However, in a solvent system containing oxygen-containing organic compounds, water alone The surface tension of the dispersion medium is lower than that of a solvent system, and sol particles (which also include linear polymers) are relatively hydrophilic. It is speculated that the sol becomes stable, and as a result, the chances of collisional association between particles are reduced, and this is due to the stabilizing effect of the β-dicarbonyl compound as a stabilizer, resulting in a stable metal oxide-based sol. There is.

When using a metal oxide sol as a surface treatment agent, carboxylic acids such as acetic acid, alcohols such as methanol and ethanol, and ethyl acetate may be used to improve adhesion to the substrate and uniform dispersion. , esters such as methyl acrylate, ethers such as ethyl ether, ketones such as acetone, lower hydrocarbons such as LPG and LNG, their halides and (meth)acrylic acid, 2- and droxyethyl (meth) Water-soluble or emulsified monopolymers or copolymers of reactive heptamers such as acrylate, vinyl acetate, maleic acid, ethylene oxide, etc., and surfactants can be co-present.

The present invention will be explained in more detail with reference to Examples below.

Example 1 Titanium tetrachloride aqueous solution (Ti-containing ffi 16.8% by weight)
168 g, 447 m of pure water and 12°39 acetylacetone
was added to make a homogeneous solution. To this solution, 600 (l) of an anion exchange resin (Amberlite "IRA-68, manufactured by Rohm and Haas) whose ion exchange groups were previously converted to OH type was added with a wet resin, and after contacting at 25°C for 35 minutes, the above A stable titania sol was produced by furnace-separating the ion exchange resin.The composition of this sol was such that titania was Ti 0
2, it is 7°5% by weight, chlorine ion (Cf') is 0.65% by weight, and acetylacetone (number of moles)/T+(
number of children) -0.2. The particle size of the colloid was observed using a dynamic light scattering photometer (DLS-700 manufactured by Union Giken), and the average particle size was 40. Further, this sol remained stable without gelation and thickening even after being left at air temperature for 3 months, but when no acetylacetone was added, the sol thickened after 2 days and turned into jelly after 4 days.

Example 2 Instead of using titanium tetrachloride aqueous solution in Example 1, zirconyl oxychloride (ZrOCj!2 ・8) + 20
) Using an aqueous solution, acetylacetone was added immediately after the ion exchange resin was separated, and then a portion of the solvent water was distilled off under reduced pressure to increase the sol concentration. A zirconia sol shown in Table 1 was obtained.

Examples 3 to 14 Instead of using titanium tetrachloride in Example 1, salts of each element shown in Table 1 below were used as raw materials, and the stabilizers shown in Table 1 were used as raw materials.
Various metal oxide-based sols were obtained in the same manner as in Example 1, except that the chelating agent or metal chelate shown in Example 1 was used. All of these sols remained stable even after three months had passed since they were manufactured.

Example 15 Titanium tetrachloride 50 (] and zirconyl oxychloride (Z
rOCj! 2-8H20) 84.9 (J) was added and dissolved in 160 d of a 13° 2% aqueous solution of acetylacetone to form a homogeneous solution. This solution was heated from the outside while stirring, and thermally hydrolyzed at 160'C for 1 hour. The chloride ions were then removed by dialysis through a cellophane membrane.The pH of the solution at this time was 3.0.The obtained titania-zirconia composite sol had Ti/Zr=1/1 (atomic ratio). , Sol 111 degrees 2 converted to Ti○2 + ZrO2
5 weight ω%, number of moles of acetylacetone/number of (Ti+Zr) atoms = 0.4. The average particle size of the colloid was 0.023 μm as measured using a transmission electron microscope, and did not change even after one month of production.

The water in the colloid was distilled off under a reduced pressure of 100 Torr to obtain acetylacetone-coordinated titania-zirconia composite hydrate fine particles, which were then calcined at 500°C to produce titania-zirconia fine particles. The average particle size of these fine particles is 0.0
It was 7 μm.

Incidentally, titania-zirconia particles were produced in the same manner as described above except that acetylacetate was added, but the average particle size had grown to 0.2 μm.

Example 16 330a of indium chloride (InCj!3.4H20) and 33g of tinnic chloride (SnCfa.3H20) were dissolved in 1140 (l) of a 0.1 M HC1 aqueous solution containing 25() of acetylacetone, and this solution was converted into OH type in advance. Anion exchange resin (product name: Duolite A-3)
40) 6j! The indium oxide-tin oxide composite sol was produced by passing the liquid through a column filled with the following at a rate of SV 208 r''.The composition of the sol was ln/5n = 10.8 (atomic ratio),
Sol concentration converted to In2O3+SnO3 13.1% by weight, number of moles of acetylacetone/number of (In+Sn) atoms =
1.6, and the average particle diameter was 0.03 μm. Both the sol and the sol diluted to a sol concentration of 72 with ethanol showed no thickening phenomenon even after 3 months at 25°C, and were stable without forming a precipitate.

In addition, in the above manufacturing method, an indium oxide-tin oxide composite sol was manufactured in the same manner as the manufacturing method except that acetylacetone was not used and 1.59% of acetic acid was included instead of cetyl acetone, but in both cases, scuttling occurred after 24 hours. After one month, almost all the oxides were precipitated and separated.

Example 17 Titanium tetrachloride aqueous solution (Ti content 16.8% by weight) 168
447 g of isopropyl alcohol (IPA) and 35.4 g of acetylacetone (+) were added to make a homogeneous solution. This solution was wetted with an anion exchange resin (IRA-68) whose ion exchange group had been previously converted to 0)-1 type. 9 with resin
00! After adding + and contacting at 25° C. for 45 minutes, the above ion exchange resin was separated from the furnace to produce a stable titania sol in an IPA solvent system.

The composition of this sol is 7 when titania is converted to T i 02.
．． 3% by weight, chlorine ion <CI! -) is 0.04% by weight
So, acetylacetone (number of moles)/Ti (number of atoms) = 0
．． It was 6. The particle size of the colloid was observed using a dynamic light scattering photometer, and the average particle size was 30 particles. Further, this sol remained stable without gelation or thickening even after being left at room temperature for 6 months, but it turned into jelly during the reaction when acetylacetone was not added.

Example 18 Zirconyl oxychloride (ZrOCj!2 ・8H20)
67 () with 447 g of methanol and 16 acetylacetone
．． 7 () was added to make a homogeneous solution. To this solution, an ion exchange resin (Amberlite 01RA-410 manufactured by Rohm and Haas) was added as a wet resin 3709, and after contacting for 10 minutes at 25°C, the above ion exchange resin was separated into a furnace. A stable zirconia sol in a methanol solvent system was produced.The composition of this sol was 4.8% by weight of zirconia, calculated as ZrO2, and 0.01% by weight of chloride ions (<CI!-). Acetylacetone (number of moles)/Zr (number of atoms) = 0.8. The particle size of the colloid was observed using a dynamic light scattering photometer, and the average particle size was 40.

Further, this sol remained stable without gelation or thickening even after being left at room temperature for 6 months, but it turned into jelly during the reaction when acetylacetone was not added.

Examples 19 to 30 Instead of using titanium tetrachloride in Example 17, the salts of each element shown in Table 2 below were used as raw materials, the chelating agent or metal chelate shown in Table 2 was used as a stabilizer, and a dispersion medium was used. Various metal oxide-based sols were obtained in the same manner as in Example 17, except that methanol was used. All of these sols remained stable even after 6 months had passed since their manufacture.

Examples 31 to 35 A stable titania sol was obtained in the same manner as in Example 17, except that the solvent shown in Table 3 was used instead of isopropyl alcohol. All of these sols remained stable even after 6 months had passed since their manufacture.

Table-3

Claims (1)

[Scope of Claims] (1) A chelating agent and/or Alternatively, a stable metal oxide sol composition characterized in that it contains a metal chelate. (2) the chelating agent is a β-dicarbonyl compound,
The metal oxide-based sol composition according to claim (1), wherein the metal chelate is a β-dicarbonyl metal chelate. (3) A patent characterized in that the number of moles of chelating molecules in the chelating agent and/or metal chelate is present in a range of 0.05 to 2.0 times the number of moles of the metal atoms constituting the particles. A metal oxide-based sol composition according to claim (1) or (2). (4) The particles are an oxide or hydroxide of at least one metal selected from the group consisting of titanium, zirconium, cerium, vanadium, niobium, tantalum, aluminum, gallium, indium, tin, manganese, nickel, cobalt, and iron. A metal oxide-based sol composition according to claim (1), (2) or (3), which contains a condensate as a main component. (5) Claim (1), (2), (3) or (4), wherein the dispersion medium constituting the metal oxide sol is water and/or an oxygen-containing organic compound. metal oxide-based sol composition.