JPH1111932A - Production of fine aluminosilicate particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably ensure more stable ink absorbing property and fixability by mixing and hydrolyzing a silicon alkoxide and an aluminum alkoxide and heat-treating the resultant sol. SOLUTION: A silicon alkoxide and an aluminum alkoxide are mixed and hydrolyzed and the resultant sol is heat-treated under the conditions of 5-50% concn., 100-250 deg.C and elevated pressure. The treatment is preferably carried out in an autoclave with a stirrer so as to allow reaction to proceed uniformly. The treatment temp. is preferably 120-180 deg.C. The silicon alkoxide is preferably methoxide, ethoxide, n-propoxide or i-butoxide of silicon, in particular silicon tetraethoxide. The aluminum alkoxide is preferably aluminum isoproxide. Acetonitrile, n-propanol or isopropanol is preferably used as an org. solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing aluminosilicate fine particles.

[0002]

2. Description of the Related Art Ink jet recording systems have been widely used for printers and the like in recent years because of their features such as low noise and easy adaptation to colorization. In general, an ink jet recording paper is provided with a pigment-based coating layer on the paper in order to correspond to a color, and a pigment mainly containing silica is generally used. In many cases, the coating layer contains a cationic substance in order to fix an anionic ink. In recent years, more advanced images and strong fixability have been demanded, and the above-described conventional configuration is insufficient for the demand. The applicant has
In pursuit of a finer particle diameter and stable fixability, the inventors have previously filed a patent application by proposing the use of aluminosilicate composite fine particles as a pigment for a coating layer.

[0003]

As a method for producing aluminosilicate fine particles, there is known a method for obtaining the same particles by mixing and hydrolyzing silicate alkoxide and aluminum alkoxide. (BEYoldas., Am. Ceram. Soc. Bull., 59, 479-83, 1980) The fine particles obtained by the above method are used for various ceramic applications. However, subsequent studies by the present applicant have revealed that the aluminosilicate fine particles obtained by the above method are still insufficient as a pigment for an ink jet recording layer in terms of ink absorption and fixability. Therefore, an object of the present invention is to propose aluminosilicate fine particles capable of stably obtaining higher ink absorption and fixing properties.

[0004]

In order to solve the above problems, the present invention employs the following constitution. That is, the present invention is "a method for producing aluminosilicate fine particles, which comprises heat-treating a hydrolyzed sol in a method for producing aluminosilicate fine particles by a mixed hydrolysis method of silicate alkoxide and aluminum alkoxide". In addition, the present invention, the above-mentioned heat treatment is performed at a processing temperature of 100 ° C to 2 ° C.
A method for producing aluminosilicate fine particles, wherein the temperature is 50 ° C.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The “mixing hydrolysis method of silicate alkoxide and aluminum alkoxide” in the present invention means:
This means a method for producing aluminosilicate composite fine particles by dispersing a silicate alkoxide and an aluminum alkoxide in an organic solvent and performing mixed hydrolysis in the presence of water and, if necessary, an acid catalyst.

The aluminum alkoxide used in the present invention includes methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl and s.
Although aluminum alkoxide of ec-butyl can be used as a raw material, aluminum isopropoxide is particularly preferable among them.

The silicate alkoxide used in the present invention includes methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl,
Although c-butyl silicate alkoxide can be used as a raw material, silicon tetraethoxide is particularly preferable among them.

Further, by controlling the ratio of the alkoxide, the ratio of the alumina component (Al ₂ O ₃ ) to the silica component (SiO ₂ ) in the formed particles is 99.9: 0.1 to 0.1 to 99.9. Particles can be synthesized, preferably 99: 1
1: 1: 99, which can be used in the present invention.

The organic solvent used for the hydrolysis reaction of silicate alkoxide and aluminum alkoxide includes methyl alcohol, ethyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol. Alcohols such as butyl alcohol, acetonitrile, and the like are exemplified. Of these, n-propanol, isopropanol, and acetonitrile are preferably used because they are easy to handle. These can be used in combination. Silicic acid alkoxide and aluminum alkoxide are used in the reaction after being dissolved or dispersed in an organic solvent in the range of 3 to 70% by weight.

[0010] At the time of the hydrolysis treatment, the presence of water is necessary, and the amount of water is preferably 10 to 120 mol based on the total molar amount of the silicate alkoxide and the aluminum alkoxide.
At the time of the hydrolysis treatment, an acid catalyst is preferably used to promote the reaction. When an acid catalyst is used, hydrochloric acid and nitric acid can be used as inorganic acids, and acetic acid and formic acid can be used as organic acids. The acid is added in an amount of 0.05 to 0.3 mol per mol of silicic acid alkoxide, and 0.1 to 1 mol per mol of aluminum alkoxide.
Between 0.5 and 0.3 mol are suitable. Addition of more than 0.3 mol of an acid is not preferred because it may adversely affect the coating film when mixed with a binder and applied. Conversely, if the amount is less than 0.05 mol, the resulting particles are undesirably aggregated.

In the present invention, the mixture may be hydrolyzed as described above. As a preferred method, a silicate alkoxide is dispersed in an organic solvent in advance, water is added thereto, and the mixture is reacted. There is also a method in which aluminum alkoxide is mixed with a liquid dispersed in an organic solvent, and the mixed liquid is subjected to hydrolysis treatment. According to this method, the silica-alumina composite of the formed particles (formation of -Si-O-Al) is sufficiently performed. In the case of the above method, it is desirable that the silicate alkoxide is subjected to hydrolysis reaction in advance in an organic solvent with 0.05 to 4 mol of water per mol of alkoxide together with an acid catalyst, and the amount of water is 0.05 to 5 mol per mol of silicate alkoxide. 4 moles are preferred. If the amount of water added is less than 0.05 mol per mol of the silicate alkoxide, the partial hydrolysis of the silicate alkoxide becomes insufficient, and the silica-alumina composite product (-Si -O-Al formation)
May not be performed sufficiently. Also, when the amount of water added is 4
If the molar ratio exceeds the above range, the hydrolysis of the silicate alkoxide may proceed excessively, making it difficult for the silica-alumina to be sufficiently complexed. Further, it is desirable to add hydrochloric acid, nitric acid, and acetic acid as a reaction accelerator to the silicate alkoxide in order to more completely perform the silica alumina complexing. ~ 1.0 ×
A range of 10-4% by weight is preferred.

Regarding the hydrolysis conditions when producing the aluminosilicate composite fine particles of the present invention, the reaction temperature is 40.
C. to 100.degree. C. are preferred, and 70.degree. C. to 90.degree. C. are more preferred. When the temperature is lower than 40 ° C., the dispersion stability of the resulting aluminosilicate composite fine particles is deteriorated, and the dispersion may gel, and the desired sol particles may not be obtained, or the particle size may be excessive. The temperature is 100 ℃
If it exceeds, bumping of ethanol, propanol and the like generated by hydrolysis may be caused.

The reaction time is preferably 1 to 50 hours,
A range of 2 to 24 hours is more preferred. If the time is less than 1 hour, the hydrolysis may not proceed sufficiently. If the time exceeds 50 hours, the dispersion may be gelled, which is not preferable from the viewpoint of productivity.

Next, the sol obtained in the above manufacturing process was treated at a processing concentration of 5%.
It is a feature of the present invention that heat treatment is performed under a pressurized condition at a temperature of 100% or more at a temperature of 100% or more. The treatment reaction is preferably performed in a pressure vessel equipped with a stirrer in order to promote a uniform reaction. Heat treatment temperature is 100 ℃ ～ 25
0 ° C. is preferable, and 120 ° C. to 180 ° C. is more preferable. When the temperature is lower than 100 ° C., the hydrothermal reaction is not sufficiently performed, which is not preferable. If the treatment temperature exceeds 250 ° C. and the reaction proceeds too much, the particles may aggregate, and this is not preferable from the viewpoint of productivity.

The present inventors have found that when the aluminosilicate fine particles obtained in the above manufacturing process are applied for use in an ink jet recording medium, the pore volume formed by the aluminosilicate fine particles, particularly the pore diameter is in the range of 5 nm to 50 nm. Was found to be important. In addition, when the pore volume of aluminosilicate fine particles is mixed with the obtained sol or binder and dried or applied as a coating, the innumerable hydroxyl groups (-OH) on the surface of the aluminosilicate fine particles are polycondensed. And block the pores,
It was found that the ink might not be absorbed. On the other hand, a sol obtained by heat-treating the aluminosilicate fine particles obtained in the above-described manufacturing process or a paint mixed with a binder is less likely to cause polycondensation of hydroxyl groups even when dried, so that the ink is easily absorbed. This is presumably because the aluminosilicate particles are less likely to be in close contact with each other and the pores are less likely to be closed. In addition, the heat treatment may be performed in a state where the reaction solution after the mixed hydrolysis contains a solvent, or the solvent may be completely distilled off by an evaporator,
Heat treatment may be performed after adding water to the concentrated product.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto.

<Example 1> 131.6 g (0.61 mol, aluminum compound, manufactured by Wako Pure Chemical Industries, purity: 95) of aluminum isopropoxide was placed in a 5 liter glass reaction vessel (with a separable flask, a stirring blade, and a thermometer). %) And 1.25 kg (20.8 mol) of isopropanol, and the temperature is raised to 70 ° C. to dissolve the aluminum isopropoxide. Separately, 47.37 g of silicon tetraethoxide (0.216 mol, Wako Pure Chemical Industries, 95% purity) and 38.88 g of isopropanol are placed in a 200 cc eggplant flask.
(0.65 mol), 7.78 g (0.432 mol) of water, and react at 85 ° C. for 6 hours. After that, it is added to the above aluminum isopropoxide solution and mixed well. Thereafter, 446 g (24.8 mol) of distilled water was added to the mixture, and at the same time, 8.23 g of nitric acid (65% concentration solution,
0.085 mol), and a mixed hydrolysis reaction is performed at 85 ° C. After reacting for 12 hours, the obtained reaction solution was concentrated to remove isopropanol, and a white sol having a solid content of 15% was obtained. The obtained sol was charged into a glass autoclave and heat-treated at 160 ° C. for 2 hours. The dried product (dried at 100 ° C.) of the obtained sol had an amorphous structure by powder X-ray diffraction. The pore diameter was 20 nm as measured by a nitrogen gas adsorption method.

Next, a coating liquid (solid content concentration: 15% by weight) of an ink receiving layer comprising 95 parts by weight of aluminosilicate fine particles obtained by the above-mentioned production method and 5 parts by weight of polyvinyl alcohol (trade name: PVA140H, manufactured by Kuraray Co., Ltd.) was prepared. . Separately, high-density polyethylene (density 0.94) containing 15% by weight of anatase type titanium is coated on one side of a base paper for photographic printing paper (160 g / m ² , 0.95 sq.m.
The coating was performed at a temperature of 20 ° C., and cooled using a cooling roll having a mirror surface to form a coating layer having a coating amount of 30 g / m ^{2 on the} front surface. On the other side, low-density polyethylene (density 0.92)
In the same manner as above to form a coating layer having a coating amount of 30 g / m ^{2 on the} back surface to produce a polyolefin resin-coated paper. Next, the coating amount after drying the ink receiving layer coating solution on the front surface of the polyolefin resin coated paper with a Mayer bar is
Coating was carried out to 30 g / m ² and drying was performed to prepare an ink jet recording medium.

Example 2 A sol was prepared in the same manner as in Example 1 except that the temperature and time of the heat treatment in Example 1 were changed to 250 ° C. and 15 minutes. The average pore diameter measured by the nitrogen gas adsorption method was 16 nm. An ink jet recording medium was prepared using the above sol in the same manner as in Example 1.

Example 3 105.26 g (0.49 g) of aluminum isopropoxide was placed in a 5-liter glass reaction vessel (separable flask, equipped with a stirring blade and a thermometer).
Mol, manufactured by Wako Pure Chemical Industries, 95% purity) and 1 kg (16.7 mol) of isopropanol were added, and the temperature was raised to 70 ° C. to dissolve aluminum isopropoxide. Separately, 5.91 g (0.027 mol, purity: 95%, manufactured by Wako Pure Chemical Industries, Ltd.) of silicon tetraethoxide, 4.2 g (0.07 mol) of isopropanol, and 0.83 g of water (0 .0461), and 8
Incubate at 5 ° C for 6 hours. After that, it is added to the above aluminum isopropoxide solution and mixed well. Thereafter, 598 g (33.2 mol) of distilled water was added to the mixture, and 9.7 g (concentration: 65% solution, 0.1 mol) of nitric acid were added at the same time, and mixed hydrolysis was performed at 85 ° C. for 12 hours. The solution after the mixed hydrolysis is directly subjected to a temperature of 105
C. for 3 hours. The obtained treatment liquid was concentrated to remove isopropanol, and a sol having a solid concentration of 14% was prepared. The average pore diameter of the dried sol (dried at 100 ° C.) obtained by the nitrogen gas adsorption method in the same manner as in Example 1 was 18 nm. Further, in the same manner as in Example 1, an ink jet recording medium was prepared using the above sol.

Comparative Example 1 A sol was prepared in the same manner as in Example 1 except that the heat treatment was omitted. The average pore diameter measured by the nitrogen gas adsorption method was 3 nm. An ink jet recording medium was prepared using the above sol in the same manner as in Example 1.

<Evaluation> The ink jet recording materials obtained in the above Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 1. Gloss: 75 degree gloss was measured according to JIS K 7150. Transparency: An ink receiving layer coating liquid (solid content, 20% by weight) was prepared in the same manner as in each example and comparative example. To compare the transparency, an ink receiving layer was provided on a transparent PET film (trade name: Lumirror T, manufactured by Toray Industries, Inc., thickness: 100 μm) to prepare a sample for measuring transparency. The optical density of this sample was measured with a densitometer (trade name: PDA-65, manufactured by Konishi Roku) and converted to transmittance. Transparency: Transparency was visually evaluated by laying the ink jet recording medium prepared in each of Examples and Comparative Examples flat and irradiating light from an oblique upper surface. Those with good transparency can confirm the surface of the substrate on the sheet (or the adhesive layer on the sheet-like substrate). When the surface of the sheet-like substrate was clearly seen, it was evaluated as ○, when it was slightly hard to see, and when it was cloudy and completely invisible, it was evaluated as x. Ink fixability: After printing on an ink jet recording medium with an ink jet printer (trade name: PM700C, manufactured by Seiko Epson Corporation) and dropping water drops on the printed portion, visually observe the degree of bleeding of the ink after 60 seconds and evaluate. As' ◎ Yu,
Table 1 shows that the results were good and poor.

[0023]

[Table 1]

As is clear from Table 1, the ink jet recording materials obtained in Examples 1 to 3 were excellent in glossiness, transparency, transparency, and ink fixability.

[0025]

According to the present invention, it is possible to produce fine particles having a pore distribution suitable for ink jet recording by performing a hydrothermal treatment in the method for producing aluminosilicate fine particles. In addition, by using these fine particles for ink jet recording, particularly gloss, transparency, transparency,
In addition, it has become possible to provide an ink jet recording medium having excellent ink fixing properties. In addition, it goes without saying that the aluminosilicate fine particles obtained by the method of the present invention can be used as a pigment for other coated papers, and can also be used in other ways.

Claims (2)

[Claims] 1. A method for producing aluminosilicate fine particles by a mixed hydrolysis method of silicate alkoxide and aluminum alkoxide, wherein the sol after hydrolysis is heat-treated. 2. The treatment temperature in the heat treatment is 100 ° C. to 25 ° C.
The method for producing aluminosilicate fine particles according to claim 1, wherein the temperature is 0 ° C.