JP3998748B2

JP3998748B2 - Synthetic layered silicate

Info

Publication number: JP3998748B2
Application number: JP00880197A
Authority: JP
Inventors: 啓三鈴木; 匡記境田
Original assignee: Kunimine Industries Co Ltd
Current assignee: Kunimine Industries Co Ltd
Priority date: 1997-01-21
Filing date: 1997-01-21
Publication date: 2007-10-31
Anticipated expiration: 2017-01-21
Also published as: JPH10203822A

Description

【０００１】
【発明の属する技術分野】
本発明は、これを媒体中に分散させたときの分散系の透明性と分散安定性に優れ、しかも、分散液の粘度が極めて低いことを特徴とする合成層状ケイ酸塩に関する。
【０００２】
【従来の技術及び発明が解決しようとする課題】
増粘材として知られる層状ケイ酸塩の特徴は、増粘性、膨潤性、分散性、陽イオン交換性、吸着性、コロイド性（微粒子性）などである。合成層状ケイ酸塩は、これらの特徴の中の増粘性及びコロイド性を際立たせたものである。ところが、合成層状ケイ酸塩の用途の中には、増粘性はむしろ嫌われ、膨潤性、分散性、微粒子性、透明性のみを求められる場合もある。本発明は、従来の技術では得られていない、水に完全に分散してほぼ透明となり、しかも分散液の粘度が極めて低い合成層状ケイ酸塩を提供することを目的とする。
【０００３】
【課題を解決するための手段】
本発明者らは、合成層状ケイ酸塩について鋭意研究を重ねた結果、オートクレーブから取り出した水熱反応済みの合成層状ケイ酸塩スラリーを濾過し、水、あるいは、アルコール、ケトンなどの高極性有機溶剤で十分に洗浄し、未反応又は遊離の無機塩類を除いた後に乾燥すると、極めて増粘性の低い合成層状ケイ酸塩が得られることを見出し、この知見に基づき本発明をなすに至った。
すなわち本発明は、
（１）3%（本明細書において組成を示す％は重量％を示す）水系分散液のＢ型粘度計で測定した見掛け粘度が3 〜10cPであり、膨潤度が20ml／2g以上であり、陽イオン交換容量が50〜130 ミリ当量／100gであり、かつ、光路長10mmのセルで測定した1%分散液の可視光透過率が60% 以上であることを特徴とする合成層状ケイ酸塩、
（２）層状ケイ酸塩がスメクタイトであることを特徴とする（１）項記載の合成層状ケイ酸塩、及び
（３）層状ケイ酸塩がマグネシウム塩及び／又はアルミニウム塩と水ガラスとを水熱反応させて水熱反応処理物を得、これを濾過、洗浄して未反応又は遊離の塩類を除去後、乾燥して得られたものであることを特徴とする（１）項記載の合成層状ケイ酸塩
を提供するものである。
【０００４】
【発明の実施の形態】
本発明の合成層状ケイ酸塩は、結晶格子成分となる金属酸化物の共沈ゲルの調製、交換性陽イオン水溶液を添加したスラリーの調製、水熱反応処理、濾過・水洗の４つの工程の後に乾燥、粉砕して得られる。第１工程の共沈ゲルは、硫酸マグネシウムや塩化マグネシウムなどのマグネシウム塩水溶液及び／又は硫酸アルミニウムや塩化アルミニウムなどのアルミニウム塩水溶液とアンモニウム性水ガラス水溶液を所定のｐＨに保って沈殿物を生成させ、これを水洗、濾過して得られる。この水和ゲルは無定形で、かつ、このゲルの化学組成に応じて、最終的に生成する合成層状ケイ酸塩の組成が決まるので、モンモリロナイト、バイデライト、サポナイトといった目的の層状ケイ酸塩の構成に応じたモル比となるように各水溶液の仕込み量を調整する。本発明では、スメクタイトに類似した組成となるようにするのが好ましく、サポナイトに類似した組成となるようにするのがさらに好ましい。
【０００５】
第２工程では、まず第１工程で得た共沈ゲルに水を加え、攪拌してスラリー状とし、これに交換性陽イオンの水溶液、例えばアルカリ金属の水酸化物、炭酸塩、フッ化物、あるいはこれらの混合物の水溶液を加えて十分に攪拌する。交換性陽イオンは例えばナトリウムイオン、カリウムイオンなどであり、ここで加える水溶液は例えば水酸化ナトリウム水溶液などがあげられる。
第３工程では、上記第２工程で調製した出発ゲル組成物スラリーをオートクレーブに仕込み、１００〜３５０℃で自生圧力下攪拌しながら反応を行うことにより、スラリーを水熱処理する。
第１〜３工程については、例えば特公昭６３−６４８６号に記載の合成層状ケイ酸塩の製造方法の第３工程までの方法などを採用することができる。
【０００６】
本発明では第４工程として、前記第３工程で得られたスラリーを濾過、洗浄し、未反応又は遊離の無機塩類を除去する。これを乾燥・粉砕すると、増粘性の低い合成層状ケイ酸塩を得ることができる。
本発明の第４工程における洗浄は水又は有機溶媒によって行うことができる。水で洗浄する場合には、洗浄液の導電率が３００μｓ／ｃｍ以下になるまで洗浄することが好ましく、スラリー１００ｍｌに対し水又は温水３０ｍｌ以上を用いて３回以上洗浄するのが好ましい。有機溶媒を用いる場合は、アルコール、ケトンなどの高極性有機溶媒を用いることができ、スラリー１００ｍｌに対し有機溶媒５０ｍｌ以上で３回以上洗浄することが好ましい。
また、水で洗浄した後、有機溶媒で水を置換してから乾燥、粉砕を行うこともできる。有機溶媒による置換を行って乾燥すると多孔質の軟らかいケーキが得られ、軽い解砕で粉末にすることができる。
【０００７】
このようにして得られる本発明の合成層状ケイ酸塩は、増粘性の発現は殆どみられないにもかかわらず、従来の合成層状ケイ酸塩に劣らぬ膨潤力と陽イオン交換能を有し、分散液がほとんど無色透明であるという特性を有する。これらの性状は、第１工程での各成分のモル比や第４工程の洗浄の度合いなどにより異なるが、本発明においては、3%水系分散液をＢ型粘度計（60rpm で測定）見掛け粘度が通常3 〜10cP、好ましくは4 〜7cP 、さらに好ましくは4 〜5cP であり、水中での膨潤度が20ml／2g以上、好ましくは30ml／2g以上、陽イオン交換容量が50〜130 ミリ当量／100g、好ましくは60〜100 ミリ当量／100gであり、かつ、光路長10mmのセルで測定した1%分散液の可視光透過率が60% 以上、好ましくは80% 以上、より好ましくは90% 以上である。
【０００８】
【発明の効果】
既存の合成層状ケイ酸塩は、水系スラリーの比重を高めようとして濃度を上げると、粘度も上昇してしまい、高比重・低粘度でしかも分散安定性に優れたスラリーを得ることは不可能であった。
本発明の合成層状ケイ酸塩は、上記のような性質を有することにより、層状ケイ酸塩の増粘性以外の種々の性質の発現を期待して、水系分散液や水系スラリーに所望の量を配合することができ、しかも分散性、分散安定性に優れている。したがって、例えば、水より比重を高めた分散液を得たい場合に、従来の合成層状ケイ酸塩を用いると分散液の比重とともに粘度も大きく上昇するが、本発明の合成層状ケイ酸塩を水に懸濁させると、比重は高いが粘度は水よりわずかに高いだけに抑えられた、高比重低粘度の分散安定性に優れた分散液を得ることができる。しかも、本発明の合成層状ケイ酸塩の分散液は可視光透過率が高いので、透明性のよい分散系を提供でき、その利用範囲は広い。
【０００９】
【実施例】
次に、本発明を実施例に基づいてさらに詳細に説明する。
実施例１
35℃の温水190 リットルに硫酸マグネシウム136.6kg を溶解し、溶液１を調製した。一方、30℃の温水36リットルに硫酸アルミニウム19.6kgを溶解し溶液２を、30℃の温水170 リットルに３号ケイ酸ナトリウム132.6kg 及び水酸化ナトリウム34.6kgを溶解し溶液３を、それぞれ調製した。
溶液１に溶液３を攪拌しながら45分間かけて徐々に加えた。ここに、溶液２を20分間かけて徐々に加えた。この混合溶液のｐＨを測定しながら、9.4 になるように20％の水酸化ナトリウム溶液を加えた。
生成した原料ゲルは、フィルタープレスで濾過、洗浄を行い、ケーキは水800 リットルとともにオートクレーブに移した。ここに、水酸化ナトリウム１〜３kgを水10リットルに溶解した溶液を加えてｐＨを10.1〜10.2に調整した後、オートクレーブを密封し、温度250 ℃、自生圧力40kg/cm²の条件で3.5 時間水熱処理を行った。水熱反応後の合成層状ケイ酸塩スラリー900 リットルを、フィルタープレスで濾過し、60℃の温水300リットルで３回洗浄して、未反応あるいは遊離の塩類を除いた後、乾燥、粉砕して試料１を70kg得た。
【００１０】
実施例２
水熱処理、濾過、温水による洗浄までは、実施例１と全く同様に処理し、その後、ケーキをメチルアルコール100 リットルで洗浄して水をアルコールで置換した後に乾燥・解砕して試料２を70kg得た。アルコール置換を行った後に乾燥すると、多孔質の軟らかい乾燥ケーキが得られ、強力な粉砕をせずとも、軽い解砕で試料２を得ることができた。
【００１１】
実施例３
メチルアルコールの代わりにアセトンを用いた以外は実施例２と全く同様に処理し、試料３を70kg得た。実施例２と同様に多孔質で軟らかい乾燥ケーキが得られ、軽い解砕で試料３を得ることができた。
【００１２】
比較例１
水熱処理までは実施例１と全く同様に処理し、得られた合成層状ケイ酸塩スラリーを、濾過も洗浄もせずに、そのまま乾燥、粉砕して試料４を得た。
比較例２
水熱処理までは実施例１と全く同様に処理し、得られた合成層状ケイ酸塩スラリーを、濾過だけ行い、洗浄はせずに乾燥、粉砕して試料５を得た。
【００１３】
実施例１〜３及び比較例１〜２で得た各試料について、次の測定を行った。
（１）粘度
各試料の３％水分散液の２５℃における見掛け粘度をＢ型粘度計で６０ｒｐｍで測定した。
（２）膨潤度
水中での各試料の膨潤度を測定した。
（３）陽イオン交換容量
（４）可視光透過率
各試料の１％水分散液について、光路長１０ｍｍ、波長５００ｎｍの光透過率（水を１００％とした）を測定した。
結果を表１に示す。
【００１４】
【表１】

【００１５】
表１の結果より、本発明の合成層状ケイ酸塩は、従来の合成層状ケイ酸塩（比較試料１及び２）に比較して、膨潤力はわずかに劣るものの、同等の陽イオン交換容量を有し、分散液の可視光透過率が高く、しかも粘度が極めて低いことがわかる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthetic layered silicate characterized in that the dispersion is excellent in transparency and dispersion stability when dispersed in a medium, and the viscosity of the dispersion is extremely low.
[0002]
[Prior art and problems to be solved by the invention]
The characteristics of layered silicates known as thickeners are thickening, swelling, dispersibility, cation exchange, adsorption, colloidal (particulate), and the like. Synthetic layered silicates highlight the thickening and colloidal properties among these features. However, in some applications of synthetic layered silicates, thickening is rather disliked, and only swelling, dispersibility, fine particle properties, and transparency may be required. An object of the present invention is to provide a synthetic layered silicate which is not obtained by the prior art and is completely transparent in water and becomes almost transparent, and the viscosity of the dispersion is extremely low.
[0003]
[Means for Solving the Problems]
As a result of extensive research on the synthetic layered silicate, the present inventors filtered the hydrothermally reacted synthetic layered silicate slurry taken out of the autoclave and added water or a highly polar organic material such as alcohol or ketone. It was found that a synthetic layered silicate with extremely low viscosity can be obtained by thoroughly washing with a solvent, removing unreacted or free inorganic salts and then drying, and based on this finding, the present invention has been made.
That is, the present invention
(1) 3% (% indicating composition in this specification indicates% by weight) The apparent viscosity of the aqueous dispersion measured with a B-type viscometer is 3 to 10 cP, and the degree of swelling is 20 ml / 2 g or more. A synthetic layered silicate having a cation exchange capacity of 50 to 130 milliequivalents / 100 g and a visible light transmittance of 1% dispersion measured in a cell having an optical path length of 10 mm of 60% or more ,
(2) The synthetic layered silicate according to item (1), wherein the layered silicate is smectite, and (3) the layered silicate is water containing magnesium salt and / or aluminum salt and water glass. A synthesis product according to item (1), which is obtained by subjecting to thermal reaction to obtain a hydrothermal reaction treated product, which is filtered and washed to remove unreacted or free salts and then dried. A layered silicate is provided.
[0004]
DETAILED DESCRIPTION OF THE INVENTION
The synthetic layered silicate of the present invention comprises four steps: preparation of a metal oxide co-precipitated gel as a crystal lattice component, preparation of a slurry to which an exchangeable cation aqueous solution is added, hydrothermal reaction treatment, filtration and water washing. It is obtained after drying and pulverization. The coprecipitation gel in the first step generates a precipitate by maintaining an aqueous magnesium salt solution such as magnesium sulfate and magnesium chloride and / or an aqueous aluminum salt solution such as aluminum sulfate and aluminum chloride and an aqueous ammonium water glass solution at a predetermined pH. This is obtained by washing with water and filtering. This hydrated gel is amorphous, and the composition of the synthetic layered silicate that is ultimately produced is determined according to the chemical composition of the gel, so the composition of the desired layered silicate such as montmorillonite, beidellite, saponite, etc. The amount of each aqueous solution charged is adjusted so that the molar ratio is in accordance with. In the present invention, a composition similar to smectite is preferable, and a composition similar to saponite is more preferable.
[0005]
In the second step, first, water is added to the coprecipitated gel obtained in the first step, and the mixture is stirred to form a slurry. An aqueous solution of an exchangeable cation such as an alkali metal hydroxide, carbonate, fluoride, Alternatively, an aqueous solution of these mixtures is added and sufficiently stirred. The exchangeable cation is, for example, sodium ion or potassium ion, and the aqueous solution added here is, for example, sodium hydroxide aqueous solution.
In the third step, the starting gel composition slurry prepared in the second step is charged into an autoclave, and the slurry is hydrothermally treated by stirring and stirring at 100 to 350 ° C. under an autogenous pressure.
About the 1st-3rd process, the method to the 3rd process etc. of the manufacturing method of the synthetic layered silicate described in Japanese Patent Publication No. 63-6486 can be adopted, for example.
[0006]
In the present invention, as the fourth step, the slurry obtained in the third step is filtered and washed to remove unreacted or free inorganic salts. When this is dried and pulverized, a synthetic layered silicate with low viscosity can be obtained.
The washing in the fourth step of the present invention can be performed with water or an organic solvent. In the case of washing with water, washing is preferably performed until the conductivity of the washing solution is 300 μs / cm or less, and washing is preferably performed three or more times using 100 ml of slurry or 30 ml or more of warm water. In the case of using an organic solvent, a highly polar organic solvent such as alcohol or ketone can be used, and it is preferable to wash 3 times or more with 50 ml or more of organic solvent with respect to 100 ml of slurry.
Further, after washing with water, the water can be replaced with an organic solvent, followed by drying and pulverization. When substituted with an organic solvent and dried, a porous soft cake is obtained, which can be made into a powder by light pulverization.
[0007]
The synthetic layered silicate of the present invention thus obtained has a swelling power and cation exchange capacity comparable to those of conventional synthetic layered silicates, despite the fact that almost no thickening is observed. The dispersion has the property of being almost colorless and transparent. These properties vary depending on the molar ratio of each component in the first step and the degree of washing in the fourth step. In the present invention, a 3% aqueous dispersion is measured using a B-type viscometer (measured at 60 rpm). Is usually 3 to 10 cP, preferably 4 to 7 cP, more preferably 4 to 5 cP, the degree of swelling in water is 20 ml / 2 g or more, preferably 30 ml / 2 g or more, and the cation exchange capacity is 50 to 130 meq / 100 g, preferably 60 to 100 milliequivalents / 100 g, and the visible light transmittance of a 1% dispersion measured in a cell having an optical path length of 10 mm is 60% or more, preferably 80% or more, more preferably 90% or more It is.
[0008]
【The invention's effect】
Existing synthetic layered silicates increase the viscosity when the concentration is increased to increase the specific gravity of the aqueous slurry, and it is impossible to obtain a slurry with high specific gravity, low viscosity, and excellent dispersion stability. there were.
Since the synthetic layered silicate of the present invention has the above-mentioned properties, it is expected that various properties other than the thickening of the layered silicate are exhibited, and a desired amount is added to the aqueous dispersion or the aqueous slurry. It can be blended and has excellent dispersibility and dispersion stability. Therefore, for example, when it is desired to obtain a dispersion having a higher specific gravity than water, the viscosity increases greatly with the specific gravity of the dispersion when a conventional synthetic layered silicate is used. When the suspension is suspended, a dispersion having a high specific gravity and a low viscosity, which has a high specific gravity but is suppressed to a slightly higher viscosity than water, can be obtained. In addition, since the dispersion of the synthetic layered silicate of the present invention has a high visible light transmittance, it is possible to provide a dispersion with good transparency, and its application range is wide.
[0009]
【Example】
Next, the present invention will be described in more detail based on examples.
Example 1
Solution 1 was prepared by dissolving 136.6 kg of magnesium sulfate in 190 liters of warm water at 35 ° C. On the other hand, 19.6 kg of aluminum sulfate was dissolved in 36 liters of warm water at 30 ° C., and Solution 3 was prepared by dissolving 132.6 kg of No. 3 sodium silicate and 34.6 kg of sodium hydroxide in 170 liters of warm water at 30 ° C. .
Solution 3 was slowly added to Solution 1 over 45 minutes with stirring. To this, solution 2 was gradually added over 20 minutes. While measuring the pH of this mixed solution, a 20% sodium hydroxide solution was added so as to be 9.4.
The produced raw material gel was filtered and washed with a filter press, and the cake was transferred to an autoclave together with 800 liters of water. A solution prepared by dissolving 1 to 3 kg of sodium hydroxide in 10 liters of water was added to adjust the pH to 10.1 to 10.2, and the autoclave was sealed, and the temperature was 250 ° C. and the pressure was 40 kg / cm ² for 3.5 hours. Hydrothermal treatment was performed. 900 liters of the synthetic layered silicate slurry after the hydrothermal reaction is filtered with a filter press, washed 3 times with 300 liters of hot water at 60 ° C to remove unreacted or free salts, dried and ground. 70 kg of sample 1 was obtained.
[0010]
Example 2
The hydrothermal treatment, filtration, and washing with warm water were the same as in Example 1. Thereafter, the cake was washed with 100 liters of methyl alcohol, the water was replaced with alcohol, dried and crushed, and 70 kg of Sample 2 was obtained. Obtained. When dried after alcohol substitution, a porous soft dry cake was obtained. Sample 2 could be obtained by light crushing without intensive crushing.
[0011]
Example 3
The sample was treated in the same manner as in Example 2 except that acetone was used instead of methyl alcohol to obtain 70 kg of Sample 3. As in Example 2, a porous and soft dry cake was obtained, and Sample 3 could be obtained by light crushing.
[0012]
Comparative Example 1
The treatment until the hydrothermal treatment was carried out in exactly the same manner as in Example 1, and the obtained synthetic layered silicate slurry was dried and pulverized as it was without being filtered or washed to obtain Sample 4.
Comparative Example 2
The process up to hydrothermal treatment was carried out in exactly the same manner as in Example 1, and the obtained synthetic layered silicate slurry was filtered only, dried and pulverized without washing to obtain Sample 5.
[0013]
The following measurements were performed on the samples obtained in Examples 1 to 3 and Comparative Examples 1 and 2.
(1) Viscosity The apparent viscosity at 25 ° C. of a 3% aqueous dispersion of each sample was measured with a B-type viscometer at 60 rpm.
(2) Swelling degree The swelling degree of each sample in water was measured.
(3) Cation exchange capacity (4) Visible light transmittance For a 1% aqueous dispersion of each sample, the light transmittance of an optical path length of 10 mm and a wavelength of 500 nm (with water as 100%) was measured.
The results are shown in Table 1.
[0014]
[Table 1]

[0015]
From the results of Table 1, the synthetic layered silicate of the present invention has an equivalent cation exchange capacity, although the swelling power is slightly inferior to the conventional synthetic layered silicate (Comparative Samples 1 and 2). It can be seen that the dispersion has a high visible light transmittance and a very low viscosity.

Claims

The apparent viscosity of a 3% aqueous dispersion measured with a B-type viscometer is 3 to 10 cP, the degree of swelling is 20 ml / 2 g or more, the cation exchange capacity is 50 to 130 meq / 100 g, and the optical path A synthetic layered silicate characterized in that the visible light transmittance of a 1% dispersion measured in a 10 mm long cell is 60% or more.

The synthetic layered silicate according to claim 1, wherein the layered silicate is smectite.

The layered silicate is hydrothermally reacted with magnesium salt and / or aluminum salt and water glass to obtain a hydrothermal reaction treated product, which is filtered and washed to remove unreacted or free salts and then dried. The synthetic layered silicate according to claim 1, which is obtained.