High pH silica-aluminum-containing colloidal aqueous solution

Abstract

The challenge is to develop a silica-aluminum-containing colloidal aqueous solution that remains stable even at pH levels above 10. [Solution] A high pH silica-aluminum-containing colloidal aqueous solution containing colloidal silica, aluminum, oxycarboxylic acid, and quaternary ammonium hydroxide as constituent components, and satisfying the following requirements [1] to [4]: ​​[1] pH is in the range of greater than 10 and less than or equal to 13; [2] The number of moles of SiO2 (A) and the number of moles of Al2O3 (B) are in the range of A / B = 0.01 to 1000; [3] The product of the number of moles of oxycarboxylic acid and the number of carboxyl groups in the oxycarboxylic acid (C) and B are in the range of C / B = 1 to 6; [4] The number of moles of quaternary ammonium hydroxide (D) and C are in the range of D / C = 0.5 to 150.

Description

Technical Field

[0001] The present invention relates to a silica-aluminum-containing colloidal aqueous solution in a high pH region.

Background Art

[0002] The applicant of the present application disclosed Patent Document 1 as a silica-aluminum-containing colloidal aqueous solution. The constituent components of the silica-aluminum-containing colloidal aqueous solution are colloidal silica, aluminum, oxycarboxylic acid, and an alkali (excluding alkanolamine).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the silica-aluminum-containing colloidal aqueous solution described in Patent Document 1, when the pH exceeds 10, precipitation and gelation are likely to occur regardless of the length of the storage period. Therefore, it was difficult to apply to uses where a pH region exceeding 10 is required.

[0005] An object of the present invention is to develop a stable silica-aluminum-containing colloidal aqueous solution even when the pH exceeds 10.

Means for Solving the Problems

[0006] The inventors of this invention, after diligently investigating the above-mentioned problems, have surprisingly discovered that by using quaternary ammonium hydroxide as the alkali, a silica-aluminum-containing colloidal aqueous solution with excellent stability in the pH range above 10 can be obtained. Furthermore, in Patent Document 1, the silica sol used as the raw material could not be used as is and had to be diluted, so the only way to obtain a high-concentration product was to first manufacture a silica-aluminum-containing colloidal aqueous solution and then concentrate it. However, by using quaternary ammonium hydroxide, the silica sol used as the raw material can be used as is, that is, a high-concentration silica-aluminum-containing colloidal aqueous solution can be manufactured without a concentration step. This invention is based on these findings.

[0007] The present invention is as follows: [1] A high pH silica-aluminum-containing colloidal aqueous solution containing colloidal silica, aluminum, oxycarboxylic acid, and quaternary ammonium hydroxide as constituent components, and satisfying the requirements of [1] to [4] below. [1] The pH is in the range of greater than 10 and less than or equal to 13. [2] The number of moles of SiO2 (A) and the number of moles of Al2O3 (B) are in the range of A / B = 0.01 to 1000. [3] The product of the number of moles of oxycarboxylic acid and the number of carboxyl groups in the oxycarboxylic acid (C), and B, are in the range of C / B = 1 to 6. [4] The number of moles of quaternary ammonium hydroxide (D) and the above C are in the range of D / C = 0.5 to 150. [2] A powder obtained by drying the high pH silica-aluminum-containing colloidal aqueous solution described in [1] above. [Modes for carrying out the invention]

[0008] The present invention will be described in detail below based on preferred embodiments, but the present invention is not limited to the following embodiments, and various modifications are possible within the scope of the claims. In this invention, the notation "value 1 to value 2" in relation to a numerical range means a numerical range that includes both values ​​1 and 2, with value 1 as the lower limit and value 2 as the upper limit, and is synonymous with "value 1 or greater and value 2 or less".

[0009] The high pH silica-aluminum-containing colloidal aqueous solution of the present invention (hereinafter also referred to as "the aqueous solution of the present invention") contains colloidal silica, aluminum, oxycarboxylic acid, and quaternary ammonium hydroxide as constituent components, and satisfies the following conditions [1] to [4]. [1] The pH is in the range of greater than 10 and less than or equal to 13. [2] The number of moles of SiO2 (A) and the number of moles of Al2O3 (B) are in the range of A / B = 0.01 to 1000. [3] The product of the number of moles of oxycarboxylic acid and the number of carboxyl groups in the oxycarboxylic acid (C), and B, are in the range of C / B = 1 to 6. [4] The number of moles of quaternary ammonium hydroxide (D) and the above C are in the range of D / C = 0.5 to 150.

[0010] (Components) The colloidal silica is not particularly limited as long as it originates from an acidic to alkaline silica sol. The particle shape is also not particularly limited as long as it is known in the art. Furthermore, it is preferable that it originates from a silica sol in an aqueous solvent.

[0011] Good examples of oxycarboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, and glycolic acid, with lactic acid being particularly preferred.

[0012] Examples of quaternary ammonium hydroxides include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylpropylammonium hydroxide, dimethyldiethylammonium hydroxide, and choline. Among these, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and choline are particularly recommended due to their effectiveness in dispersion stabilization and ease of availability.

[0013] The aqueous solution of the present invention may contain ammonia as long as its stability is not compromised, but is preferably substantially ammonia-free. Here, substantially ammonia-free means that, apart from ammonia derived from impurities in the raw materials, it contains no ammonia. A more preferable aqueous solution of the present invention is one that contains no ammonia at all.

[0014] Furthermore, the aqueous solution of the present invention may contain alkali metals and alkaline earth metals, as long as it does not impair stability. The amount of alkali metals present in silica sol, which is the raw material for colloidal silica, is not particularly problematic.

[0015] (Requirement 1) The aqueous solution of the present invention has a pH in the range of greater than 10 and less than or equal to 13. Within this range, the aqueous solution of the present invention is less likely to form precipitates and therefore has high stability. The lower limit of the above pH range is preferably 10.1, more preferably 10.2, even more preferably 10.3, even more preferably 10.4, particularly preferably 10.5, and particularly more preferably 11. Therefore, examples of preferred pH ranges include 10.1-13, 10.2-13, 10.3-13, 10.4-13, 10.5-13, and 11-13.

[0016] (Requirement 2) In the aqueous solution of the present invention, when A is the number of moles of SiO2 and B is the number of moles of Al2O3, the A / B ratio is in the range of 0.01 to 1000. In the region where A / B is close to the lower limit, it is presumed that ionic aluminum, aluminum-modified colloidal silica, and alumina sol (colloidal alumina) coexist, and in the region where A / B is close to the upper limit, it is presumed that colloidal silica makes up the majority, with some aluminum-modified colloidal silica and ionic aluminum present. In the aqueous solution of the present invention, the quantitative ratios of aluminum, oxycarboxylic acid, and quaternary ammonium hydroxide are specified by C / B in requirement 3 and D / C in requirement 4, so A / B can take on the wide range described above.

[0017] (Requirement 3) In the aqueous solution of the present invention, the ratio C / B (number of moles of Al2O3) is in the range of 1 to 6, where C is the product of the number of moles of oxycarboxylic acid and the number of carboxyl groups in the oxycarboxylic acid. If C / B is less than 1, there will be insufficient oxycarboxylic acid necessary for stabilizing the aluminum component, and for example, a precipitate of aluminum hydroxide may form. On the other hand, even if C / B is greater than 6, if D / C is in the range of 0.5 to 150, it will exhibit similar physical properties to the aqueous solution of the present invention. However, considering applications where the aqueous solution of the present invention is subjected to calcination treatment, a lower organic acid content is preferable.

[0018] In the aqueous solution of the present invention, D is the number of moles of quaternary ammonium hydroxide, and the relationship with C (the product of the number of moles of oxycarboxylic acid and the number of carboxyl groups in the oxycarboxylic acid) is such that D / C is in the range of 0.5 to 150. If D / C is less than 0.5 or more than 150, precipitate formation and gelation are likely to occur regardless of the length of storage period. The appropriate range of D / C tends to change depending on A / B; for example, a higher D / C is preferable when A / B is high, and a lower D / C is preferable when A / B is low.

[0019] The ratio of C / B to D / C results in a range of D / B = 0.5 to 900, and the aqueous solution of the present invention is valid even within this range of D / B.

[0020] Regarding the total amount of the SiO2 concentration and the Al2O3 concentration in the aqueous solution of the present invention (hereinafter referred to as "total SiO2-Al2O3 concentration"), it cannot be generally stated as it varies depending on the ratio of SiO2 and Al2O3. However, as a guideline, when the ratio of SiO2 is high, the total SiO2-Al2O3 concentration is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. When the ratio of Al2O3 is high, the total SiO2-Al2O3 concentration is preferably 20% by mass or less. Also, when the ratio of SiO2 and Al2O3 is equivalent, the total SiO2-Al2O3 concentration is preferably 30% by mass or less. In each of the above cases, when the total SiO2-Al2O3 concentration exceeds the above value, the viscosity increases and the handling property tends to deteriorate. Regarding the lower limit of the total SiO2-Al2O3 concentration in any of the above cases, there is no particular limitation, but from an economic perspective, it is preferably 1% by mass, and more preferably 3% by mass.

[0021] The aqueous solution of the present invention can be concentrated by ultrafiltration or heating, etc., as necessary, and used, or can be diluted with water, etc., and used. However, since all aluminum components cannot be recovered by ultrafiltration, heating concentration is preferred.

[0022] The appearance of the aqueous solution of the present invention is transparent to milky white, and no precipitate is formed. Note that it tends to become milky white as the ratio of silica increases.

[0023] The aqueous solution of the present invention shows no change at least for one month even when stored at 50°C, as well as when stored at room temperature, and has excellent long-term storage stability.

[0024] Regarding the viscosity of the aqueous solution of the present invention, there is no particular limitation as long as it maintains appropriate fluidity as a solution. Preferably, the viscosity measured by an E-type viscometer at 25°C is 100 mPa·s or less, more preferably 50 mPa·s or less, and even more preferably 10 mPa·s or less.

[0025] As described above, the aqueous solution of the present invention has excellent storage stability, and furthermore, the composition ratio of silica and aluminum components can be set over a wide range. This makes it suitable for applications requiring high pH, ​​such as optical materials, electronic materials, surface treatment agents or additives for plated steel sheets such as zinc and electrical steel sheets, various binders for ceramic fiber molding and refractories, coating agents, carriers for catalysts, and ink receiving layers for inkjet recording media.

[0026] (Manufacturing method) The method for producing the aqueous solution of the present invention will now be described. Since there is virtually no loss outside the system in this production method, the amount of components derived from the raw materials is retained in the final product. Therefore, the composition ratio of the aqueous solution of the present invention is determined by the component ratio derived from the raw materials.

[0027] The present invention provides a method for producing an aqueous solution, which involves mixing silica sol, quaternary ammonium hydroxide, and an aqueous solution of an aluminum salt of an oxycarboxylic acid, followed by heating.

[0028] In this manufacturing method, there are no particular restrictions on the mixing method as long as aggregation and precipitation due to the reaction between silica sol and oxycarboxylic acid can be prevented. Examples of mixing methods include (a) simultaneously adding silica sol, quaternary ammonium hydroxide, and an aqueous solution of the aluminum salt of oxycarboxylic acid; (b) mixing silica sol and quaternary ammonium hydroxide and then adding the aqueous solution of the aluminum salt of oxycarboxylic acid; (c) mixing the aqueous solution of the aluminum salt of oxycarboxylic acid and quaternary ammonium hydroxide and then adding silica sol; and (d) mixing silica sol and the aqueous solution of the aluminum salt of oxycarboxylic acid and then adding quaternary ammonium hydroxide.

[0029] Quaternary ammonium hydroxide is thought to play a role in preventing aggregation and precipitation during the reaction between silica sol and oxycarboxylic acid. Therefore, in any of the above mixing methods, it is desirable to appropriately set conditions such as the component concentration of the raw materials and the stirring intensity according to the mixing order. Of the above mixing methods, methods (b) and (c) are more preferable because they allow for the mediation of quaternary ammonium hydroxide in the reaction between silica sol and oxycarboxylic acid. Furthermore, methods (b), (c), and (d) are suitable for producing high-concentration aqueous solutions of the present invention because silica sol can be used as a raw material without dilution.

[0030] Next, we will describe the raw materials used in the first manufacturing method. Silica sols can be acidic or alkaline, and either those manufactured by known methods or commercially available ordinary silica sol products may be used. The particle shape is not particularly limited as long as it is known in the art. Furthermore, a silica sol in an aqueous solvent, so-called aqueous silica sol, is preferred. Specific examples of silica sols include the Snowtex series manufactured by Nissan Chemical Industries, Ltd., the Cataloid series manufactured by JGC Catalysts & Chemicals Inc., and silica sols handled by Nippon Chemical Industrial Co., Ltd. Generally, when using acidic silica sols, the content of Na and other elements is significantly lower, so they can be selected according to the application.

[0031] Specific examples of quaternary ammonium hydroxides, as mentioned above, include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylpropylammonium hydroxide, dimethyldiethylammonium hydroxide, choline, and the like.

[0032] An aqueous solution of an aluminum salt of an oxycarboxylic acid is an aqueous solution containing an oxycarboxylic acid and ionic aluminum. Specific examples of oxycarboxylic acids are, as above, lactic acid, citric acid, malic acid, tartaric acid, glycolic acid, etc. Examples of aluminum salts of oxycarboxylic acids include aluminum lactate, aluminum citrate, aluminum malate, basic aluminum lactate, aluminum lactate citrate, aluminum lactate glycolate, aluminum glycolate, etc. One or more of these may be used. The ratio of oxycarboxylic acid to aluminum in the aqueous solution of the aluminum salt of an oxycarboxylic acid is within the C / B range described above, i.e., C / B = 1 to 6. Note that the aqueous solution of the aluminum salt of an oxycarboxylic acid may contain inorganic acid rhizomes derived from the manufacturing raw materials, inorganic acid rhizomes added for stabilization of the aqueous solution, etc.

[0033] Here, as specific examples of aqueous solutions of aluminum salts of oxycarboxylic acids, we will describe aqueous solutions of aluminum lactate and basic aluminum lactate, where the oxycarboxylic acid is lactic acid. These may be prepared using commercially available industrial chemicals or those obtained by known manufacturing methods. For example, an aqueous solution of aluminum lactate may be prepared by dissolving commercially available aluminum lactate (C / B=6), or a commercially available aqueous solution of basic aluminum lactate (e.g., Takceram®: manufactured by Taki Chemical Co., Ltd., pH 4-5, C / B=1.5-1.6, Al2O3 concentration=8-9% by mass) may be used. Examples of known manufacturing methods include Japanese Patent Publication No. 58-5174 and Japanese Patent Publication No. 59-40381, which disclose methods for producing basic aluminum lactate. Of these, those with C / B=1-2 are suitable for use in the present invention because they have high stability as basic salts.

[0034] The mixing ratio of silica sol to the aqueous solution of the aluminum salt of oxycarboxylic acid is in the range of A / B = 0.01 to 1000. The reason why a stable aqueous solution of the present invention can be obtained in such a wide A / B range is thought to be the presence of quaternary ammonium hydroxide in the reaction between silica sol and oxycarboxylic acid, as described above. Considering this in more detail, it is presumed that colloidal silica and some of the ionic aluminum derived from the aqueous solution of the aluminum salt of oxycarboxylic acid exist as aluminum-modified colloidal silica via quaternary ammonium hydroxide. Furthermore, it is presumed that the stabilization of the remaining ionic aluminum by the oxycarboxylic acid (and the coexistence of alumina sol in cases where the aluminum content is high) contributes to the improved stability.

[0035] Regarding the heating performed after mixing, the heating temperature is preferably 90 to 200°C, and more preferably 90 to 140°C. High stability can be obtained by performing heating. There are no particular restrictions on the heating method, and examples include conventional heating methods and autoclaves. As heating increases, the particle size of the particles in the aqueous solution of the present invention tends to increase, so it is preferable to appropriately set the heating conditions (temperature, time, etc.) according to the desired particle size. The heating time can be set as appropriate, for example, 1 to 10 hours is preferable.

[0036] The aqueous solution of the present invention can be dried to obtain a redispersible silica-aluminum-containing colloidal powder. Redispersibility means that when the powder is suspended in water, it returns to the aqueous solution of the present invention. The powder can be used as is, or dispersed in a small amount of water to achieve high concentrations. Commonly used drying methods such as spray drying, static drying, and airflow drying can be employed. A drying temperature of 150°C or lower is preferred. [Examples]

[0037] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. As silica sols, Cataloid SN manufactured by JGC Catalysts & Chemicals Co., Ltd. and Snowtex C manufactured by Nissan Chemical Corporation were used.

[0038] [Example 1] 0.09 parts by mass of Cataloid SN (SiO2=20% by mass, Na2O=0.025% by mass, pH3) manufactured by JGC Catalysts & Chemicals Co., Ltd. were mixed with 16.00 parts by mass of 35% TEAH, and then 33.25 parts by mass of basic aluminum lactate aqueous solution (Al2O3=9.2% by mass, lactic acid=10.2% by mass, pH4) were slowly added. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=0.01, C / B=1.25, D / C=1.01, SiO2=0.04 mass%, Al2O3=6.23 mass%, pH12.8, and EC37.4 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0039] [Example 2] To a mixture containing 15.1 parts by mass of Cataloid SN (SiO2=20% by mass, Na2O=0.025% by mass, pH3) manufactured by JGC Catalysts & Chemicals Co., Ltd., 11.3 parts by mass of deionized water and 0.1 parts by mass of basic aluminum lactate aqueous solution (Al2O3=9.2% by mass, lactic acid=10.2% by mass, pH4) were added slowly, and then 3.60 parts by mass of 35% TEAH were slowly added. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=999, C / B=1.25, D / C=133, SiO2=10.3% by mass, Al2O3=0.0175% by mass, pH11.9, and EC11.4 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0040] [Example 3] To a mixture of 0.09 parts by mass of Cataloid SN (SiO2=20% by mass, Na2O=0.025% by mass, pH3) manufactured by JGC Catalysts & Chemicals Co., Ltd., 33.25 parts by mass of basic aluminum lactate aqueous solution (Al2O3=9.2% by mass, lactic acid=10.2% by mass, pH4) was added slowly, followed by the slow addition of 15.00 parts by mass of 35% TEAH. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=0.01, C / B=1.25, D / C=0.95, SiO2=0.04 mass%, Al2O3=6.36 mass%, pH10.6, and EC35.6 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0041] [Example 4] To a mixture containing 15.1 parts by mass of Cataloid SN (SiO2=20% by mass, Na2O=0.025% by mass, pH3) manufactured by JGC Catalysts & Chemicals Co., Ltd., 11.6 parts by mass of deionized water and 0.1 parts by mass of basic aluminum lactate aqueous solution (Al2O3=9.2% by mass, lactic acid=10.2% by mass, pH4) were added slowly, and then 3.30 parts by mass of 35% TEAH were slowly added. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=999, C / B=1.25, D / C=122, SiO2=10.3% by mass, Al2O3=0.0175% by mass, pH10.9, and EC10.6 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0042] [Example 5] A solution was prepared by diluting 4.9 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4) with 15.9 parts by mass of deionized water. This solution was then simultaneously added and mixed with 23.5 parts by mass of Cataloid SN (SiO2 = 20% by mass, Na2O = 0.025% by mass, pH 3) manufactured by JGC Catalysts & Chemicals Co., Ltd. and 5.63 parts by mass of 35% TEAH. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=18, C / B=1.25, D / C=2.40, SiO2=9.4% by mass, Al2O3=0.91% by mass, pH11.0, and EC10.2 mS / cm. Furthermore, the above aqueous solutions immediately after production were concentrated using an evaporator to a total SiO2-Al2O3 concentration of 15% by mass, 20% by mass, 30% by mass, 40% by mass, and 50% by mass, respectively. The viscosities of the obtained high-pH silica-aluminum-containing colloidal aqueous solutions were 2.3 mPa·s, 2.9 mPa·s, 7.3 mPa·s, 32.1 mPa·s, and 5532 mPa·s, respectively. Even after storage at room temperature for one month, no gelation or precipitate formation was observed in any of them, indicating that they maintained their stability.

[0043] [Example 6] To a solution prepared by adding 14.0 parts by mass of deionized water to 4.9 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4), 7.51 parts by mass of 35% TEAH were mixed under stirring, and then 23.5 parts by mass of Cataloid SN (SiO2 = 20% by mass, Na2O = 0.025% by mass, pH 3) manufactured by JGC Catalysts & Chemicals Co., Ltd. were mixed. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=18, C / B=1.25, D / C=3.20, SiO2=9.4% by mass, Al2O3=0.91% by mass, pH12.9, and EC11.7 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0044] [Example 7] To a solution prepared by adding 12.3 parts by mass of deionized water to 3.9 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4), 4.96 parts by mass of 35% TEAH were mixed under stirring, and then 18.8 parts by mass of Nissan Chemical Corporation's Snowtex C (SiO2 = 20% by mass, Na2O = 0.034% by mass, pH 9) were mixed. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=18, C / B=1.25, D / C=2.64, SiO2=9.4% by mass, Al2O3=0.91% by mass, pH10.2, and EC11.2 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0045] [Example 8] To a solution prepared by adding 1.13 parts by mass of 88% L-lactic acid and 9.7 parts by mass of ion-exchanged water to 2.9 parts by mass of a basic aluminum lactate aqueous solution (Al2O3=9.2% by mass, lactic acid=10.2% by mass, pH4), 3.64 parts by mass of 35% TEAH were mixed in while stirring, and then 13.8 parts by mass of Cataloid SN (SiO2=20% by mass, Na2O=0.025% by mass, pH3) manufactured by JGC Catalysts & Chemicals Co., Ltd. were mixed in. Next, this mixture was heated at 90°C for 1 hour to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=18, C / B=5.45, D / C=0.60, SiO2=9.1% by mass, Al2O3=0.86% by mass, pH12.0, and EC18.5 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0046] [Example 9] To a solution prepared by adding 0.20 parts by mass of DL-malic acid and 10.0 parts by mass of ion-exchanged water to 2.9 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4), 3.50 parts by mass of 35% TEAH were mixed in while stirring, and then 13.7 parts by mass of Cataloid SN (SiO2 = 20% by mass, Na2O = 0.025% by mass, pH 3) manufactured by JGC Catalysts & Chemicals Co., Ltd. were mixed in. Next, this mixture was subjected to hydrothermal treatment at 110°C for 1 hour to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=18, C / B=2.40, D / C=1.34, SiO2=9.3% by mass, Al2O3=0.88% by mass, pH11.1, and EC16.1 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0047] [Example 10] To a mixture of 8.8 parts by mass of Cataloid SN (SiO2=20% by mass, Na2O=0.025% by mass, pH3) manufactured by JGC Catalysts & Chemicals Co., Ltd., 14.1 parts by mass of basic aluminum lactate aqueous solution (Al2O3=9.2% by mass, lactic acid=10.2% by mass, pH4) was added slowly, followed by the slow addition of 11.7 parts by mass of 35% TEAH. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=2.3, C / B=1.25, D / C=1.74, SiO2=5.2% by mass, Al2O3=3.8% by mass, pH12.8, and EC22.4 mS / cm. Visual observations of the above aqueous solution immediately after preparation, after storage at 50°C for 1 month, and after storage at room temperature for 4 months revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0048] [Example 11] To a mixture containing 12.7 parts by mass of Cataloid SN (SiO2=20% by mass, Na2O=0.025% by mass, pH3) manufactured by JGC Catalysts & Chemicals Co., Ltd., 5.3 parts by mass of a basic aluminum lactate aqueous solution (Al2O3=9.2% by mass, lactic acid=10.2% by mass, pH4) was added under stirring, and then 5.4 parts by mass of 35% TEAH was slowly added. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=9.0, C / B=1.25, D / C=2.14, SiO2=11.1% by mass, Al2O3=2.1% by mass, pH11.8, and EC15.6 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0049] [Example 12] 18.8 parts by mass of Nissan Chemical Corporation's Snowtex C (SiO2 = 20% by mass, Na2O = 0.034% by mass, pH 9) was mixed with 3.9 parts by mass of basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4) under stirring, and then 5.0 parts by mass of 35% TEAH was slowly added. Next, this mixture was subjected to hydrothermal treatment at 140°C for 3 hours to obtain a high pH silica-aluminum-containing colloidal aqueous solution with A / B=18, C / B=1.56, D / C=2.12, SiO2=13.6% by mass, Al2O3=1.3% by mass, pH11.2, and EC11.2 mS / cm. Visual observation of the above aqueous solution immediately after preparation and after storage at 50°C for one month revealed no gelation or precipitate formation, indicating that it maintained its stability.

[0050] (powder) The high-pH silica-aluminum-containing colloidal aqueous solution obtained in Example 5 was dried statically in a forced-air dryer at 100°C to obtain a powder. When this powder was dispersed in ion-exchanged water to the same concentration as before drying, the Tyndall effect was observed, and the pH was 11.0. From this, it was found that the powder dispersed in water exhibited the properties of the high-pH silica-aluminum-containing colloidal aqueous solution of the present invention.

[0051] [Comparative Example 1] To a solution prepared by adding 26.4 parts by mass of deionized water to 0.3 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4), 2.0 parts by mass of 23% aqueous ammonia (NH3) was mixed in under stirring, and then 1.4 parts by mass of Cataloid SN (SiO2 = 20% by mass, Na2O = 0.025% by mass, pH 3) manufactured by JGC Catalysts & Chemicals Co., Ltd. was mixed in. Next, when this mixture was subjected to hydrothermal treatment at 140°C for 3 hours, a white precipitate was observed after the hydrothermal treatment, and a high-pH silica-aluminum-containing colloidal aqueous solution was not obtained. The raw material was prepared with A / B=19, C / B=1.6, D / C=70.8, SiO2=0.9% by mass, and Al2O3=0.08% by mass. After hydrothermal treatment, the pH was 10.2 and the EC was 0.8 mS / cm.

[0052] [Comparative Example 2] To a solution prepared by adding 28.3 parts by mass of deionized water to 0.3 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4), 0.1 parts by mass of monoisopropanolamine (MIPA) was mixed under stirring, and then 1.4 parts by mass of Cataloid SN (SiO2 = 20% by mass, Na2O = 0.025% by mass, pH 3) manufactured by JGC Catalysts & Chemicals Co., Ltd. was mixed. Next, when this mixture was subjected to hydrothermal treatment at 140°C for 3 hours, it gelled after the hydrothermal treatment, and a high-pH silica-aluminum-containing colloidal aqueous solution could not be obtained. The raw material composition was as follows: A / B=19, C / B=1.6, D / C=2.1, SiO2=0.9 mass%, Al2O3=0.08 mass%.

[0053] [Comparative Example 3] To a solution prepared by adding 1.1 parts by mass of deionized water to 14.1 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4), 6.0 parts by mass of 35% TEAH were mixed under stirring, and then 8.8 parts by mass of Nissan Chemical Corporation's Snowtex C (SiO2 = 20% by mass, Na2O = 0.034% by mass, pH 9) were mixed. Next, when this mixture was subjected to hydrothermal treatment at 140°C for 3 hours, it gelled after the hydrothermal treatment, and a high-pH silica-aluminum-containing colloidal aqueous solution could not be obtained. The raw material preparation ratios were A / B=2.3, C / B=1.6, D / C=0.72, SiO2=6.0% by mass, and Al2O3=4.35% by mass. The pH before hydrothermal treatment was 9.9.

[0054] [Comparative Example 4] 10.0 parts by mass of a basic aluminum lactate aqueous solution (Al2O3 = 9.2% by mass, lactic acid = 10.2% by mass, pH 4) was mixed with 12.5 parts by mass of 35% TEAH under stirring, and then 10.6 parts by mass of Cataloid SN (SiO2 = 20%, Na2O = 0.025%, pH 3) manufactured by JGC Catalysts & Chemicals Co., Ltd. was mixed in. Next, when this mixture was subjected to hydrothermal treatment at 140°C for 3 hours, turbidity and solid-liquid separation were observed after the hydrothermal treatment, and a high-pH silica-aluminum-containing colloidal aqueous solution could not be obtained. The raw material was prepared with the following ratios: A / B=4.0, C / B=1.6, D / C=2.1, SiO2=6.6% by mass, and Al2O3=2.78% by mass. The pH before hydrothermal treatment was 13.7, the pH after hydrothermal treatment was 13.2, and the EC was 22.2 mS / cm.

Claims

1. A high-pH silica-aluminum-containing colloidal aqueous solution containing colloidal silica, aluminum, oxycarboxylic acid, and quaternary ammonium hydroxide as constituent components, and satisfying the following requirements [1] to [4]. [1] The pH is in the range of greater than 10 and less than or equal to 13. [2] SiO 2 The number of moles (A) and Al 2 O 3 The number of moles (B) is in the range of A / B = 0.01 to 1000. [3] The product of the number of moles of oxycarboxylic acid and the number of carboxyl groups in the oxycarboxylic acid (C), and B, are in the range of C / B = 1 to 6. [4] The number of moles of quaternary ammonium hydroxide (D) and the above C are in the range of D / C = 0.5 to 150.

2. A powder obtained by drying the high pH silica-aluminum-containing colloidal aqueous solution described in claim 1.