JPH0686341B2 - Surface modification composition of inorganic oxide and method for producing the same - Google Patents

Description

Detailed Description of the Invention

The present invention relates to a surface-modifying composition of an inorganic oxide having a specific organic decomposition product attached to its surface. Such a composition can be advantageously produced by hydrothermally treating certain organic compounds and inorganic oxides. According to the invention, in particular:
A ceramic raw material having excellent plasticity is provided.

[0002]

2. Description of the Prior Art Among conventional inorganic oxide ceramic raw materials, such as alumina, zirconia, and kaolinite, they have poor plasticity, and for the purpose of improving them, high molecular weight organic substances and inorganic plasticizers (or solvent-soluble raw materials). ) Is often added and used. For example, as in JP-A-2-160656, there is a method in which a polysaccharide is added to a non-plastic inorganic powder to impart plasticity. However, some of these do not show sufficient plasticity, on the contrary, they are too sticky and difficult to mold, or they are difficult to dry, and the shrinkage that occurs during drying and firing is too large, which causes deformation of the molded body. Some have the drawback that they tend to crack or crack.

By the way, as another attempt for general surface modification of inorganic oxides, a method of directly chemically bonding an organic substance to the inorganic oxide or a derivative thereof by applying a coupling reaction or the like is also performed. For example, Japanese Patent Publication Sho 60-2
Although there is a ceramic article whose surface is covered with ceramics to increase durability as in Japanese Patent No. 5399, it is not intended to improve plasticity. Further, there is a method of forming a thermal decomposition coating on the surface of the refractory particles as in JP-A-3-257007, but this method is a reaction which requires 600 to 1500 ° C. in a non-aqueous system.

Furthermore, the proceedings of the Annual Meeting of the Ceramic Society of Japan. VOL. As described on page 1991.138 (1991), a hydroxyapatite-chitin complex was prepared by hydrothermal hot pressing using chitin as an organic substance and hydroxyapatite as an inorganic substance at a temperature of 130 ° C. or lower at which chitin does not decompose. Improves toughness. On the other hand, there has been a problem that alumina, zirconia, kaolinite, etc., which are widely used as a ceramic raw material, and ceramic products manufactured from these materials are melted under hydrothermal conditions and gradually deteriorate. For example, α-alumina (α-A1 ₂ O ₃ ) has a problem when it is changed to aluminum hydroxide (gibbsite and boehmite) in a raw material powder state at a high temperature containing water of 100 ° C. or higher, and similarly in an alumina product. There is a problem that dissolution occurs under the same conditions and deterioration occurs.

Therefore, heat treatment of a ceramic raw material in an aqueous atmosphere has not been carried out except for the case of using the hydrothermal hot press.

[0006]

With the recent development of ceramics technology, the range of application of ceramics products has been diversified, the shapes have become complicated, and the environmental conditions used have also diversified. By the way, high-quality ceramic raw materials, such as Motoyama Kibushi clay, are already depleted, and frog eye clay is being depleted, and poor quality raw materials must be used. For example, Georgia Kaolin is a natural inorganic oxide boasting a huge reserve, but it cannot be used alone because of its poor plasticity. In order to meet the demands for such viewpoints and those exhibiting even more excellent properties, there are increasing opportunities to use artificial raw materials having artificially controlled properties.

Under such circumstances, it would be meaningful in the art to provide various organically modified inorganic oxides excellent in plasticity and durability and a method for producing the same.
Therefore, it is an object of the present invention to provide a new composition, in which an inorganic oxide having a problem of plasticity and durability as a ceramic raw material is provided with excellent plasticity and durability, and a method for producing the same.

[0008]

In order to solve the above-mentioned problems, the present inventors have found that the conditions under which good-quality clay is produced are such that clay minerals and organic compounds are complexed by corrosion in the presence of water over a long period of time. As a result of repeated intensive research, the addition of a certain organic compound to the inorganic oxide ceramics raw material,
It was found that a composition in which the above problems were solved can be obtained by hydrothermal treatment in an aqueous atmosphere, and the present invention was completed.

Therefore, according to the present invention, there is provided a surface-modifying composition for an inorganic oxide, wherein an organic decomposition product of an organic compound which can be decomposed by hydrothermal treatment in the presence of an inorganic oxide is attached to the surface. The above-mentioned problems are solved by.
The present invention is also directed to a method for producing such a surface modification composition. The surface-modified composition of the inorganic oxide obtained in this manner was such that the inorganic oxide was colored in the same color as the organic decomposed product, and this coloring was not decolorized by repeated washing with water, and it was confirmed by differential thermal analysis (DTA) and powder X-ray diffraction. It has been confirmed that the surface of the inorganic oxide is modified by organic decomposition products. Furthermore, the plasticity of such a surface-modifying composition was evaluated by the viscosity of the slurry and the plastic limit water content. Furthermore, when the durability of this surface modification composition was evaluated by a test under hydrothermal conditions, all showed good properties.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The inorganic oxide used in the present invention is generally a compound or composition comprising one or more inorganic oxides which can be a main constituent phase of a ceramic raw material. As long as the purpose of can be achieved, its origin and type are not limited. Specifically, silicon,
Those containing an oxide (or a composite oxide) of one or more elements selected from aluminum, titanium, zirconium and a mixture thereof as a main constituent, and a hydrate thereof (or an inorganic compound derived from these oxides) Acid) is the inorganic oxide referred to in the present invention. These oxides include other minor inorganic oxides or salts that form natural minerals,
For example, calcium carbonate, calcium oxide, iron oxide, barium carbonate, barium oxide, chromium oxide and the like may be contained, and when a part of the main constituent components are in the form of an inorganic acid, they may be converted into a salt. It may be included in the form.

More specifically, in connection with the ceramic raw material, the inorganic oxides include, for example, synthetic materials such as alumina, zirconia, kaolinite,
Mullite, cordierite, hydroxyapatite, etc.
Examples of natural materials include poorly plastic kaolin minerals such as Georgia kaolin, sepiolite and bone ash.

For the purpose of the present invention, the above-mentioned inorganic oxides having poor plasticity are preferably used. Among them, kaolin, sepiolite and other bentonites having excellent plasticity are also included in the inorganic oxides of the present invention. . Further, layered silicate minerals having a special structure, such as mica, chlorite, talc, smectite, serpentine, etc., are also included in the category of the inorganic oxide in the present invention. Of these, when they inherently have excellent plasticity, they can be used for the purpose of modifying the plasticity according to the present invention and further improving the durability as described above. .

The organic compounds which can be decomposed by hydrothermal treatment in the presence of these inorganic acid compounds are those which can be decomposed by hydrothermal treatment and adhere to the surface of the inorganic oxide to achieve the object of the present invention. If so, it can be used regardless of its type. Generally, sugars and their derivatives, amino acids and their derivatives, hydrophilic synthetic polymers and the like are used. Sugars and their derivatives are concepts including monosaccharides to polysaccharides,
Specifically, mannose, glucose, fructose, galactose, xylose and other monosaccharides, maltose, lactose, sucrose, palatinose, raffinose, starch hydrolyzed starch syrup and other oligosaccharides, hydrogenated to the reducing sugar portion of the saccharides. Mannitol, sorbitol, xylitol, maltitol, lactitol,
Palatinit, sugar alcohol such as reduced starch syrup, starch,
Examples thereof include polysaccharides such as glycogen, cellulose, mannan, pectin, alginic acid, chitin, hemicellulose, plant gum, plant mucilage, red algal mucilage polysaccharide, starch, carboxymethylcellulose, and methylcellulose.

As amino acids and their derivatives,
Glycine, alanine, valine, leucine, isoleucine, serine, threonine, cysteine, cystine, methionine, aspartic acid, glutamic acid, lysine, arginine, phenylalanine, tyrosine, histidine, tryptophan, proline oxyproline, and their esters and polymers, for example, Examples include gelatin, casein, and the like. As the hydrophilic synthetic polymer, polyethylene oxide, polyvinylpyrrolidone,
Included are polyethylene glycol and polyvinyl alcohol, as well as polyacrylic acid, polymethacrylic acid and their esters. Further, various waxes including melanin resin and polyurethane may be used. Of these, sugars and their derivatives can be particularly preferably used.

The hydrothermal treatment referred to in the present invention means an operation of treating the organic compound with water in the presence of an inorganic oxide at a temperature of more than 100 ° C. Through this operation, the organic compound is decomposed and the organic decomposed product is attached to the surface of the coexisting inorganic oxide. The mechanism of this adhesion has not been clarified, but the organic decomposition products are chemically or physically bound to each other by the interaction with the surface of the inorganic oxide under hydrothermal treatment conditions. It is believed that such provides the surface modification composition of the present invention.

In this way, the plasticity of the composition of which the surface is modified by the organic decomposition product becomes good, in the raw material inorganic oxide, the viscosity of the slurry, the plasticity limit water content, and the plasticity diagram showing the plasticity, so-called It can be understood that those which deviate from the region of organic clay come into the region of organic clay (hatched portion in FIG. 1, liquidity limit of 50% or more, plasticity index of 30 or more) by using the composition of the present invention. (For the significance of the plasticity diagram, soil physics-Foundation of soil engineering-
(See Soil Physics Research Society, Morikita Publishing, p. 21).

The composition of the present invention can be conveniently prepared by hydrothermally treating the inorganic oxide and the organic compound in an aqueous atmosphere. As the hydrothermal treatment, a temperature exceeding 100 ° C. is selected as the condition as described above, but in consideration of practical easiness of operation, at a temperature of 350 ° C. or lower, preferably 100 to 220 ° C., a closed system, that is, Usually done in an autoclave. Further, the aqueous atmosphere refers to a reaction environment in a gas phase or a liquid phase mainly composed of water under pressure, and specific conditions are appropriately selected depending on the properties of the inorganic oxide and the organic compound used. . In this atmosphere, nitrogen gas, other inert gas or lower alcohol is added for the purpose of adjusting the pressure or increasing the affinity of the organic compound to the liquid phase when the liquid phase is used. May be.

The ratio of the organic compound and the inorganic oxide added to the hydrothermal treatment system is not limited because it varies depending on the kinds of these raw materials used and the intended degree of modification.
Generally, the organic compound is 0.05 to 5 relative to the inorganic oxide.
It is used at 0% by weight, preferably 0.1-10% by weight. The treatment time also varies depending on both raw materials used, but when a monosaccharide is used as the organic compound, the treatment temperature is 100 to 375 ° C. and the treatment time is 30 seconds to 7 seconds.
It is good to take a day.

The characteristics and the like of the composition of the present invention thus obtained will be specifically described in the following examples.

[0020]

EXAMPLES Hereinafter, for the purpose of facilitating the further understanding of the present invention, the specific method for producing the composition of the present invention and the physical properties of the obtained composition will be clarified. The percentages in the examples are expressed in% by weight unless otherwise specified. Example 1 Synthetic kaolinite powder (artificial clay diffusion society: TD) 80
g, 40 ml of distilled water was placed in a 100 ml high-temperature, high-pressure decomposition vessel (autoclave), and methyl polymethacrylate (reagent grade, degree of polymerization = 6000, hereinafter abbreviated as PMMA).
1.0%, 5.0 to the synthetic kaolinite powder
%, Or 10.0%, and the temperature is 180 ℃ for 1 day, 2
It reacted for 3 days. After the reaction was completed, distilled water was added to bring the total volume to 300 ml, and the mixture was stirred and centrifuged to remove the supernatant. Furthermore, the total amount was made up to 300 ml with distilled water, and stirring and centrifugation were repeated 3 times to obtain a surface-modified synthetic kaolinite composition. The obtained composition was dried and pulverized at 40 ° C., and powder X-ray diffraction (XRD) / differential thermal analysis (DTA) was performed.
-The presence or absence of surface modification by an organic compound was confirmed by thermogravimetric analysis (TG). As for the DTA measurement result, the combustion peak of the organic compound was not observed in the system without PMMA addition,
In the PMMA-added system, a fuel peak due to each organic compound was observed at about 350 ° C. Further, from the measurement result of TG, the PMMA decomposition adhesion rate to kaolinite was 150-40%.
It was calculated from the weight loss at 0 ° C.

The results are shown in Table 1.

[0022]

[Table 1]

The sample before and after the treatment of the present invention (PMMA
The XRD measurement result chart for 5.0% addition) is shown in FIG. From Table 1, it was found that kaolinite was modified with a certain amount of organic compound according to the addition ratio of PMMA, and from FIG. 2, it was revealed that the modified composition was stabilized.

Example 2 Low soda alumina powder (manufactured by Sumitomo Aluminum Co., Ltd .: A
ES-11C) 80 g and distilled water 40 ml were put in a 100 ml high-temperature high-pressure decomposition vessel, and sugar alcohol (Niken Chemical Co., Ltd.)
Manufacturing: S57) and 10% of granulated sugar were added and reacted at temperatures of 110 ° C, 150 ° C and 180 ° C for 3 days. This reaction product was washed with distilled water three times in the same manner as in Example 1 to obtain a surface-modified low soda alumina. In the same manner as in Example 1, the obtained composition was checked for the presence of surface modification with an organic compound.

The XRD measurement result is the PMMA of Example 1.
It was shown that the inorganic oxide was stabilized similarly to the additive-treated product. The TG measurement results are shown in Table 2.

[0026]

[Table 2]

Example 3 The alumina composition surface-modified with granulated sugar in Example 2 was washed 5 times with 5 times the amount of distilled water. There was no change in the amount of modification of the organic compound with the number of washings, and it was found that the decomposed organic compound was strongly adsorbed or bound to the alumina surface.

Example 4 16 ml of distilled water was added to 2 g of each low-soda alumina modified with two kinds of organic compounds at each reaction temperature prepared in Example 2, and the treatment temperature was set in a high-temperature high-pressure decomposition vessel having a volume of 25 ml. 110 ℃, 150 ℃ and 180 ℃ respectively
Was processed. The results of XRD measurement without addition, sugar alcohol addition, and granulated sugar addition are shown in FIGS.
Shown in. When no organic compound is added, gibbsite (aluminum hydroxide) is generated at 110 ° C and boehmite (aluminum hydroxide) is generated at 150 ° C or higher, but no change is observed in the surface-modified alumina, and hydrothermal conditions are used. It was shown to be stable below.

Example 5 50 g of natural high whiteness Kansai kaolin and 50 g of granulated sugar were placed in a 300 ml Erlenmeyer flask equipped with a reflux tube,
After 100 ml of distilled water was added and the mixture was boiled for one day with stirring with a magnetic stirrer equipped with a heater, it was washed four times with 300 ml of distilled water to remove excess organic matter.

It was confirmed that the Kansai kaolin composition was colored brown and was modified with an organic compound. XRD
No changes were observed in Kansai Kaolin. Example 6 A rotary decomposition reaction vessel having a volume of 100 ml (Sanai Kagaku Co., Ltd.)
30 g of low soda alumina (AES-11C) and sugar alcohol (manufactured by Nikken Chemical Co., Ltd., S-100) in 5)
g, 30 ml of water and 60 g of alumina balls with a diameter of 4 mm
And was rotated for 2 days at a temperature of 180 ° C. in a circulating air electric furnace with a rotating shaft. The low soda alumina taken out after cooling was colored. After sufficiently washing this, the amount of modified organic matter was measured by TG. As a result, 0.71% of the decomposed organic matter was modified with respect to the modified low soda alumina composition.

Example 7 Mullite powder (manufactured by Kyoritsu Kikai Co., Ltd .: KM Mullite 1)
01) 4 g, dry yeast (reagent) 0.4 g, and water 10 ml are put in a high temperature and high pressure container whose inner container has a capacity of 20 ml made of titanium,
The reaction was carried out at 240 ° C for 12 hours. After the reaction, the mullite was colored dark brown and examined by XRD. As shown in FIG. 6, no change in the mullite itself was observed.

Example 8 Cordierite powder weighing 5 g (marus glaze (material):
To SS-200), add 0.2 g of sugar and 10 ml of water,
The reaction was carried out at 150 ° C for 3 days. There was no change in cordierite, confirming modification by organic decomposition products. Example 9 According to Example 1, 70 ml of water was added to 100 g of the surface-modified synthetic kaolinite composition prepared by adding 10% PMMA (reagent) to make a dough, and the Pfefferkorn method (K.Pfefferk method) was used.
Orn, Sprechsaal , 1924, 57 , 297; 1925, 58 , 183,) for plasticity evaluation.

As a result, the surface-modified synthetic kaolinite composition showed a decrease in the water content PI value, which exhibited appropriate plasticity for rokuro molding. That is, the PI of the composition of the present invention is 35.6%.
And the PI of the untreated product was 39.0%. Example 10 According to Example 1, 50 g of surface-modified synthetic kaolinite composition prepared by adding 5% PMMA to 50 g of water and 50 ml of water.
% No. 1 water glass (0.3 ml) was added and dispersed in a ball mill for 2 hours, and the viscosity of the slurry was measured.

As a result, in comparison with the untreated synthetic kaolinite powder similarly slurried (cp = 1035),
Surface modified synthetic kaolinite composition (cp = 63
The viscosity of the slurry of 9) became low. Example 11 120 g of low soda alumina powder (Sumitomo Aluminium: AES-11C) at a temperature of 180 ° C., to which 120 ml of water and 10% of sugar alcohol were added, was placed in a rotary high temperature and high pressure vessel containing 240 g of 2 mmφ alumina beads. The reaction was carried out for surface modification.

Next, the Atterberg method (JIS A 1206-1)
970, JIS A 1205-1980), a plasticity diagram (Japan Unified Soil Classification Map) was created and plasticity was evaluated. As shown in Fig. 7, untreated low-soda alumina was significantly larger than the natural plasticity clay. Deviated, but surface-modified, is shown within the area of natural plastic clay. Example 12 Cellulose filter paper (manufactured by ADVANTEC) was added to 200 g of mullite powder (KM mullite 101) as filter paper milk in an amount of 7%, and water was added to the mullite powder in an amount of 200%. Surface modification was performed at 3 ° C for 3 days. Then, after thorough washing, a plasticity test was performed by the Atterberg method.

As a result, as can be seen from the plasticity diagram (Japanese uniform soil classification diagram) shown in FIG. 8, the surface treatment of the untreated kneaded clay changed to the area shown by the natural plastic clay, It was shown that the plasticity was improved. Example 13 Organically Modified Synthetic Kaolinite Powder 50 Made in Example 9
Parts and 50 parts of quartz powder are kneaded with an appropriate amount of water, and a cylinder of 5 cm × 10 mmφ is prepared using a gypsum mold, and after drying, a span of 30
A 3-point bending test was conducted in mm. When this was compared with untreated synthetic kaolinite prepared by the same operation, the bending strength (kgf / c) of surface-modified synthetic kaolinite (kgf / c
m ² ) was 45, which was improved compared to 30 of the untreated product, and the moldability was improved.

[0037]

Industrial Applicability According to the present invention, there are provided a surface modification composition of an inorganic oxide having an organic decomposition product produced by hydrothermal treatment of a certain organic compound attached to the surface thereof, and a method for producing the same. In this composition, plasticity is imparted to the starting inorganic oxide having poor plasticity, and the stability is further enhanced under hydrothermal treatment conditions. In addition, it exhibits various physical properties suitable as a ceramic raw material.

[Brief description of drawings]

FIG. 1 is a plasticity diagram for classifying general soil properties.

FIG. 2 is an XRD measurement result diagram of the composition of the present invention obtained by subjecting kaolinite to hydrothermal treatment using PMMA.

FIG. 3 is an XRD measurement result diagram of a comparative composition obtained by hydrothermally treating low-soda alumina without adding an organic substance.

FIG. 4 is an XRD measurement result diagram of the composition of the present invention obtained by hydrothermal treatment of low-soda alumina by adding sugar alcohol.

FIG. 5 is an XRD measurement result diagram of the composition of the present invention obtained by hydrothermal treatment of low-soda alumina by adding granulated sugar.

FIG. 6 is an XRD measurement result diagram of the composition of the present invention obtained by hydrothermal treatment of mullite by adding yeast.

FIG. 7 is a plasticity diagram comparing a composition obtained by hydrothermal treatment of low-soda alumina with the addition of sugar alcohol to that without addition.

FIG. 8 is a plasticity diagram comparing the composition obtained by hydrothermal treatment of mullite with the addition of cellulose with the composition without addition.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ritsuro Miyawaki 199 Sunahara-cho, Nishi-ku, Nagoya-shi, Aichi 2A, Taiyo Heights (72) Inventor Yasuo Shibasaki 1-10, Ashiki-cho, Higashi-ku, Nagoya-shi 2-31 Ashiki House ( 72) Inventor Shinichi Maruyama 2 Examiner, Hideyuki Ono, 32 Shimogawara, Katahara Town, Gamagori City, Aichi Prefecture

Claims (4)

[Claims] 1. A surface-modifying composition for an inorganic oxide, wherein an organic decomposition product of an organic compound that can be decomposed by hydrothermal treatment in the presence of an inorganic oxide is attached to the surface. 2. The inorganic oxide contains an oxide of one or more elements selected from silicon, aluminum, titanium, zirconium, magnesium and a mixture thereof or a hydrate thereof as a main constituent component. The composition as described. 3. The composition according to claim 1, wherein the organic substance is selected from sugars and their derivatives, amino acids and their derivatives, proteins and hydrophilic synthetic polymers. 4. The surface modification according to claim 1, wherein the inorganic oxide and an organic compound which can be decomposed by hydrothermal treatment in the presence of the inorganic oxide are hydrothermally treated in an aqueous atmosphere. A method for producing a composition.