JP5133532B2 - Method for producing alumina organic solvent dispersion - Google Patents

Description

  The present invention relates to a method for producing an alumina organic solvent dispersion having excellent dispersion stability.

  An alumina aqueous dispersion (alumina hydrosol, aqueous alumina sol) in which alumina fine particles are dispersed in water is used as a surface modifying material because it can form an alumina thin film.

  Since the aqueous dispersion of alumina is water, when applied to highly hydrophobic substrates such as plastic, it is difficult to apply because the wettability to the substrate is poor, and the adhesion between the formed alumina thin film and the substrate is also good. It is insufficient. Moreover, since water resistance is also inferior, it becomes a problem depending on a use. In many cases, the aqueous dispersion of alumina alone cannot achieve the target substrate modification. In order to improve these, a binder, a surfactant or the like may be used in combination.

  However, when applying an aqueous alumina dispersion, the binder must be water soluble. Therefore, the binders that can be used are limited, and improvement is often insufficient.

  As one means for solving this problem, a sol (alumina organosol) in which alumina fine particles are dispersed in various organic solvents has been studied.

Japanese Patent Application Laid-Open No. 63-185439 (Patent Document 1) discloses a glycol monodispersion of inorganic oxide fine particles and a production method thereof. Table 2 Example No. 2- (6) in the publication discloses an alumina hydrate fine particle glycol suspension (6a2). However, this alumina hydrate fine particle glycol suspension (6a2) has a problem that the dispersion stability is poor and the viscosity and the gelation easily occur.

In Japanese translations of PCT publication No. 2003-517418 (Patent Document 2), a method for producing a metal oxide dispersible in an organic solvent, which is modified with an organic sulfonic acid, and the metal oxide and dispersion medium Dispersions containing aprotic polar solvents, protic polar solvents and the like are disclosed. Depending on the physical properties of a metal oxide such as aluminum oxide modified with an organic sulfonic acid, that is, the production method, the desired dispersion stability may not be obtained.
JP-A 63-185439 Special table 2003-517418 gazette

  The problem to be solved by the present invention is to provide a method for producing an alumina organic solvent dispersion excellent in dispersion stability in various organic solvents, particularly alcohols, ethers, ketones and esters.

  As a result of intensive research, the present inventors have hydrolyzed metallic aluminum or a hydrolyzable aluminum compound in an organic solvent and peptized in the presence of an acid to obtain an alumina organic solvent dispersion. Or it hydrolyzes with 4-10 mol water with respect to a hydrolysable aluminum compound, and it becomes an alumina slurry, 0.01-0.2 mol times presence of organic sulfonic acid with respect to metal aluminum or a hydrolyzable aluminum compound The present inventors have found that the alumina organic solvent dispersion obtained by peptization below is excellent in dispersion stability in various organic solvents, and have completed the present invention.

  Preferably, the method for producing an alumina organic solvent dispersion of the present invention is characterized in that the hydrolyzable aluminum compound is an aluminum alkoxide.

  Preferably, the method for producing an alumina organic solvent dispersion of the present invention is characterized in that the organic solvent is a protic or aprotic polar organic solvent.

  More preferably, in the method for producing an alumina organic solvent dispersion of the present invention, the organic solvent is composed of alcohols having 2 to 8 carbon atoms, ketones having 3 to 8 carbon atoms, tetrahydrofuran, γ-butyrolactone, and amides. It is at least 1 sort (s) chosen from these, It is characterized by the above-mentioned.

  The method for producing an alumina organic solvent dispersion of the present invention also includes a method of replacing the alumina organic solvent dispersion produced by the above method with an organic solvent different from the organic solvent.

  Since the alumina organic solvent dispersion of the present invention is excellent in dispersion stability, it is difficult to increase viscosity and gelation, and it is easy to handle because of its low viscosity.

  Below, the manufacturing method of the alumina organic solvent dispersion liquid of this invention is demonstrated.

  The alumina in the present invention includes gibbsite, bayerite, boehmite, pseudoboehmite, diaspore, amorphous hydrated aluminum hydroxide (alumina hydrate), and γ, η, δ, ρ, κ, θ, χ, α forms. Of alumina crystals are included.

  In an organic solvent, metal aluminum or a hydrolyzable aluminum compound is hydrolyzed with a specific amount of water to form an alumina slurry, and then peptized in the presence of a specific amount of organic sulfonic acid to obtain a predetermined alumina concentration. Concentrate to

  The hydrolyzable aluminum compound includes various inorganic aluminum compounds and aluminum compounds having an organic group. Examples of inorganic aluminum compounds include salts of inorganic acids such as aluminum chloride and aluminum sulfate, aluminates such as sodium aluminate, and aluminum hydroxide. Examples of the aluminum compound having an organic group include carboxylates such as aluminum acetate, aluminum ethoxide, aluminum isopropoxide, aluminum n-butoxide, aluminum sec-butoxide, and other aluminum alkoxides, cyclic aluminum oligomers, diisopropoxy ( Examples thereof include aluminum chelates such as ethylacetoacetate) aluminum and tris (ethylacetoacetate) aluminum, and organic aluminum compounds such as alkylaluminum. Aluminum alkoxides are preferable because they have moderate hydrolyzability and easy removal of by-products, and those having an alkoxyl group having 2 to 5 carbon atoms are particularly preferable.

  The amount of water in the hydrolysis is preferably 4 to 10 moles relative to the aluminum alkoxide. More preferably, it is 5-7 mole times. When the amount of water is less than 4 mole times, hydrolysis does not proceed sufficiently, which is not preferable. When exceeding 10 mol times, since a viscosity becomes high, it is unpreferable.

  The organic solvent coexisting at the time of hydrolysis is not particularly limited, but is preferably a protic or aprotic polar organic solvent having water solubility that is mixed when the aluminum alkoxide and the predetermined amount of water are added. The protic organic solvent includes alcohols, ethers having at least one hydroxyl group, ketones or esters. Aprotic polar organic solvents include ketones, esters, ethers and the like. More preferably, alcohols having 2 to 8 carbon atoms such as ethanol, 2-propanol, 1-butanol, ethylene glycol and diethylene glycol, ketones having 3 to 8 carbon atoms such as acetone, methyl ethyl ketone and cyclohexanone, tetrahydrofuran (THF), γ-butyrolactone and amides. Examples of amides include formamide, dimethylformamide, acetamide, dimethylacetamide, formylpiperidine, acetylpiperidine, N-methylpiperidone, urea, tetramethylurea, ethyleneurea, 1,3-dimethylethyleneurea and the like.

  A plurality of organic solvents may be used in combination.

  The amount of the organic solvent used is preferably 1 to 5 times by weight with respect to the aluminum alkoxide. When the amount of the organic solvent used is less than 1 times by weight, stirring during hydrolysis becomes difficult, which is not preferable. Even if it is used in excess of 5 times by weight, it is not preferable because it only takes time to concentrate to a predetermined concentration in the subsequent step and there is no advantage.

  After adding a predetermined amount of an organic solvent, water and metallic aluminum or a hydrolyzable aluminum compound, the mixture is heated at 85 to 170 ° C. for 0.5 to 10 hours, preferably hydrothermally treated at 105 to 150 ° C. for 1 to 5 hours. If it is less than 85 ° C., it takes a long time for hydrolysis, and even if it is carried out at a temperature exceeding 170 ° C., the increase in hydrolysis rate is slight, and it is not preferable because it requires a high pressure vessel and is economically disadvantageous. If the time is less than 0.5 hours, it is difficult to control the temperature, and heating for more than 10 hours is not preferable because it only increases the process time.

  Next, the alumina slurry obtained by hydrolysis is peptized by heating in the presence of a specific amount of organic sulfonic acid.

  The organic sulfonic acid includes aromatic sulfonic acid such as benzenesulfonic acid, p-toluenesulfonic acid and dodecylbenzenesulfonic acid, and aliphatic sulfonic acid such as hexanesulfone.

  The coexistence amount of the organic sulfonic acid is 0.01 to 0.2 mol times, preferably 0.6 to 0.15 mol times with respect to the metal aluminum or the hydrolyzable aluminum compound. When it is less than 0.01 mol times, peptization does not proceed sufficiently, and the intended alumina organic solvent dispersion cannot be obtained. If it exceeds 0.2 mol times, the stability over time is lowered, which is not preferable.

  Heat at 40 to 120 ° C. for 0.5 to 10 hours, preferably 60 to 100 ° C. for 1 to 6 hours. When the temperature is lower than 40 ° C., it takes a long time for peptization, and even if it is carried out at a temperature exceeding 120 ° C., the increase in the peptization rate is slight. When the time is less than 0.5 hours, peptization is insufficient, and heating for more than 10 hours only increases the process time, which is not preferable.

Next, an alumina organic solvent dispersion liquid can be obtained by concentrating by a general method such as distillation of excess solvent by heating until a predetermined alumina concentration is reached.
Furthermore, it can be substituted with an organic solvent different from the organic solvent coexisted during the hydrolysis (solvent exchange). In order to obtain a liquid in which alumina is stably dispersed in a nonpolar organic solvent such as toluene, solvent exchange is required.

Various physical properties of the alumina organic solvent dispersion obtained by the production method of the present invention are as follows.
Alumina concentration: 5.0 to 15.0% by weight
・ Moisture: 5% or less (Karl Fischer method)
・ Initial viscosity: 600 mPa · s or less ・ Viscosity after 30 days: 600 mPa · s or less Cone plate type rotational viscometer (manufactured by Toki Sangyo Co., Ltd., RE115R type, cone angle: 1 ° 34 ′, plate diameter: 24 mm) Measurement was performed under the following conditions.

Plate temperature: 25 ° C, rotation speed: 30rpm
-Transmittance: 10-80%
-Transmittance after 30 days: 10-80%
The transmittance at 540 nm was measured with a spectrophotometer (Hitachi, Ltd., V-3000).
・ Dispersed alumina fine particles ・ Type: Gibbsite, bayerite, boehmite, pseudoboehmite, diaspore, amorphous aluminum hydroxide (alumina hydrate), and γ, η, δ, ρ, κ, θ, χ The sample obtained by removing the solvent with an α-form alumina evaporator and pulverizing was measured with an X-ray diffractometer (RINT2000 model, manufactured by Rigaku Corporation).
・ Average particle size: 0.01-1 μm
The particle size was measured with a dynamic light scattering particle size measuring apparatus (manufactured by Nikkiso Co., Ltd., Microtrac Ultrafine Particle Size Analyzer (W) model: 9340-UPA150).

  Next, examples will be shown and described in more detail, but the present invention is not limited to these examples.

Example 1
A 0.5 L autoclave was charged with 160 g of 1-butanol and 46.8 g (2.6 mol) of ion-exchanged water, and the temperature was raised to 70 ° C. while stirring. Aluminum n-butoxide 98.4g (0.4mol) was dripped over 1 hour, and it stirred at 120 degreeC for 2 hours. After adding 6.9 g (0.04 mol) of p-toluenesulfonic acid monohydrate and stirring at 90 ° C. for 1 hour, the reaction solution was concentrated to a solid content of 15% to obtain an alumina 1-butanol dispersion. Crystal form: boehmite, alumina concentration: 15% by weight, viscosity: 33 mPa · s, moisture: 0.6%, transmittance: 70% (540 nm), and average particle size was 0.055 μm.

(Example 2)
A 0.5 L autoclave was charged with 160 g of 2-propanol and 39.6 g (2 mol) of ion-exchanged water, and the temperature was raised to 70 ° C. while stirring. 81.8 g (0.4 mol) of aluminum isopropoxide was added dropwise over 1 hour, and the mixture was stirred at 120 ° C. for 1 hour. After adding 6.9 g (0.04 mol) of p-toluenesulfonic acid monohydrate and stirring at 90 ° C. for 1 hour, the reaction solution was concentrated to a solid content of 10% to obtain an alumina 2-propanol dispersion. Crystal form: boehmite, alumina concentration: 10% by weight, viscosity: 30 mPa · s, moisture: 3.0%, transmittance: 10% (540 nm), and average particle size was 0.062 μm.

(Example 3)
A 1.0 L autoclave was charged with 200 g of cyclohexanone and 50.4 g (2.8 mol) of ion exchange water, and the temperature was raised to 70 ° C. while stirring. 81.8 g (0.4 mol) of aluminum isopropoxide was added dropwise over 1 hour, and the mixture was stirred at 120 ° C. for 2 hours. After adding 6.0 g (0.034 mol) of p-toluenesulfonic acid monohydrate and stirring at 90 ° C. for 1 hour, the reaction solution was concentrated to a solid content of 10% to obtain an alumina cyclohexanone dispersion. Crystal form: boehmite, alumina concentration: 10% by weight, viscosity: 120 mPa · s, moisture: 0.8%, transmittance: 40% (540 nm), and average particle size was 0.060 μm.

Example 4
A 1.0 L eggplant flask was charged with 200 g of the alumina butanol sol obtained in Example 1 and 270 g of γ-butyrolactone, and butanol was distilled off with an evaporator to obtain 300 g of an alumina γ-butyrolactone dispersion. Crystal form: boehmite, alumina concentration: 10% by weight, viscosity: 20 mPa · s, moisture: 0.8%, transmittance: 60% (540 nm), and average particle size was 0.040 μm.

(Example 5)
A 1.0 L autoclave was charged with 160 g of 2-propanol and 43.2 g (2.4 mol) of ion-exchanged water, and the temperature was raised to 70 ° C. with stirring. 81.8 g (0.4 mol) of aluminum isopropoxide was added dropwise over 1 hour, and the mixture was stirred at 120 ° C. for 2 hours. After adding 120 g of toluene and 6.8 g (0.04 mol) of p-toluenesulfonic acid monohydrate and stirring at 90 ° C. for 1 hour, the reaction solution is concentrated to a solid content of 15%, and an alumina 2-propanol-toluene dispersion Got. Crystal form: boehmite, alumina concentration: 15% by weight, viscosity: 30 mPa · s, moisture: 3.0%, transmittance: 55% (540 nm), and average particle size was 0.055 μm.

(Comparative Example 1)
A 0.5 L autoclave was charged with 99 g of 1-butanol and 108 g (6 mol) of ion-exchanged water, and the temperature was raised to 70 ° C. while stirring. Aluminum n-butoxide 98.4g (0.4mol) was dripped over 1 hour, and it stirred at 120 degreeC for 2 hours. After adding 6.9 g (0.04 mol) of p-toluenesulfonic acid monohydrate and stirring at 90 ° C. for 1 hour, the reaction solution was concentrated to a solid content of 15% to obtain an alumina 1-butanol dispersion. Crystal form: boehmite, alumina concentration: 15% by weight, viscosity: 1500 mPa · s, moisture: 0.8%, transmittance: 72% (540 nm), and average particle size was 0.006 μm.

(Comparative Example 2)
A 0.5 L autoclave was charged with 99 g of 1-butanol and 21.6 g (1.2 mol) of ion-exchanged water, and the temperature was raised to 70 ° C. while stirring. Aluminum n-butoxide 98.4g (0.4mol) was dripped over 1 hour, and it stirred at 120 degreeC for 2 hours. 6.9 g (0.04 mol) of p-toluenesulfonic acid monohydrate was added and stirred at 90 ° C. for 1 hour. The obtained reaction liquid was in the form of a white slurry, and sediment was observed.

(Comparative Example 3) 1-butanol, water 6.5 mol times, nitric acid
A 0.5 L autoclave was charged with 160 g of 1-butanol and 46.8 g (2.6 mol) of ion-exchanged water, and the temperature was raised to 70 ° C. while stirring. Aluminum n-butoxide 98.4g (0.4mol) was dripped over 1 hour, and it stirred at 120 degreeC for 2 hours. To this, 4.1 g (0.04 mol) of 61% nitric acid was added and stirred at 90 ° C. for 1 hour. The obtained reaction liquid was in the form of a white slurry, and sediment was observed.

  Changes in viscosity and transmittance over time are shown in [Table 1].

Note 1): Addition molar ratio of water to aluminum alkoxide Note 2): Addition molar ratio of aluminum alkoxide Transmission: Hitachi Spectrophotometer V-3000 Measurement wavelength: 540 nm
Viscosity: Toki Sangyo Co., Ltd. Cone / Plate Rotational Viscometer: RE115R

  Since the alumina organic solvent dispersion obtained by the production method of the present invention is excellent in stability over time, it is useful as a surface treatment agent for plastics such as polyester, printing recording materials, pharmaceuticals that require gas barrier properties, foods, Other packaging materials for industrial materials, plastic electrical and electronic parts that require flame resistance, automotive parts materials, and plastic covering materials for agricultural houses and tunnels that require transparency, anti-fogging properties, and water resistance Useful as.

Claims (4)

When hydrolyzing metal aluminum or a hydrolyzable aluminum compound in an organic solvent and peptizing in the presence of an acid to obtain an alumina organic solvent dispersion, 4 to 10 with respect to the metal aluminum or hydrolyzable aluminum compound. It is hydrolyzed by heating at 85-170 ° C. for 0.5 to 10 hours with mol-fold water to obtain an alumina slurry, and 0.01 to 0.2 mol-fold organic sulfone with respect to metal aluminum or hydrolyzable aluminum compound. A method for producing an alumina organic solvent dispersion having a water content of 5% or less, characterized by peptization in the presence of an acid.   The method for producing an alumina organic solvent dispersion according to claim 1, wherein the hydrolyzable aluminum compound is an aluminum alkoxide.   3. The method for producing an alumina organic solvent dispersion according to claim 1, wherein the organic solvent is a protic or aprotic polar organic solvent. The organic solvent is at least one selected from the group consisting of alcohols having 2 to 8 carbon atoms, ketones having 3 to 8 carbon atoms, tetrahydrofuran, γ-butyrolactone, and amides. The manufacturing method of the alumina organic solvent dispersion liquid of description.