JPH08310881A - Porous sintered body and its production - Google Patents

Abstract

PURPOSE: To produce a porous sintered body having functions such as deodorizing property, humidity controlling property and antibacterial property and utilized as a building material and a purifying material for various gases and liqs., especially a harmful substance adsorbing material. CONSTITUTION: Oyster shell powder and a composite of sepiolite are mixed as principal starting materials, a phosphate such as aluminum prim. phosphate as a binder, a metal oxide such as TiO2 or Al2 O3 as an auxiliary binder and a clay mineral are weighed and added and an antibacterial material (zeolite, calcium phosphate or sepiolite) with carried Ag or Cu ions and water are further added. They are stirred and mixed and the resultant mixture is cast as it is or the mixture is granulated and press-molded. After drying, sintering is carried out at 500-850 deg.C in a heating furnace to obtain the objective porous sintered body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaped article having functions such as deodorizing property, humidity controlling property and antibacterial property, and more particularly to a porous sintered body in which oyster shell powder and sepiolite are compounded and a method for producing the same. It is used as a building material and for cleaning various gases and liquids, especially as an adsorbent for harmful substances.

[0002]

2. Description of the Related Art In order to improve the habitability of buildings, it is desired that wall materials and the like have functions such as deodorizing property, humidity controlling property and antibacterial property. Conventionally, there are few materials having such a function, and a calcined body of zeolite is known. Zeolites are natural and synthetic alkali-containing hydrous aluminosilicates and have pores with a three-dimensional network structure (pore diameters of 4 to 10).
Å), it is monocuric and has strong hydrophilicity.
Therefore, in order to obtain a shaped body using zeolite, it is necessary to sinter without changing the crystal structure.

As a method for obtaining a sintered body of zeolite, in order to prevent vitrification and alteration due to alkali or alkaline earth metal, a raw material is previously ion-exchanged with a vaporizable ion (for example, NH ₃ +) and a material is used. Since it is water-containing, dehydration is not performed uniformly during molding and firing, and warpage and cracks occur, so methods such as slow heating and steam curing are adopted.

Further, since zeolite itself does not have plasticity, it is necessary to add an inorganic binder such as clay or silica sol. However, since these inorganic binders block the pores of the zeolite and lower the hygroscopicity, Since the amount of binder used was limited, the sintered body could not have high mechanical strength.

[0005]

Therefore, in view of the problems of the conventional zeolite sintered body, the present invention is superior to the sintered body mainly composed of a composite of oyster shell powder and sepiolite as a novel porous structure. The present invention also provides a porous sintered body having functions such as deodorizing property, humidity control property, and antibacterial property, and a manufacturing method for achieving it easily.

[0006]

Therefore, the present invention is a porous sintered body composed of oyster shell powder, sepiolite, phosphoric acid or phosphate, and a metal oxide. It should be noted that a porous sintered body obtained by adding a zeolite carrying silver ions or copper ions, calcium phosphate or sepiolite thereto may be used.

In the method of the present invention, the blending composition is wt%.
And the ratio of oyster shell powder to sepiolite is 20: 80-8.
It is 0:20 and the total amount of oyster shell powder and sepiolite is 6
0 to 80%, phosphoric acid or phosphate 15 to 30%, titanium oxide or alumina 0 to 10%, zeolite loaded with silver or copper ions, or calcium phosphate or sepiolite 0.2 to 2%. Mix and
It is a method for producing a porous sintered body, which comprises molding and then sintering at 500 to 850 ° C. It is also possible to add water to the raw material mixture and stir it to obtain a highly viscous gel, which is then poured into a mold for molding.

[0008]

[Function] Oyster shell powder increases gas adsorption, hydrophilicity, etc. and becomes the skeleton of the structure of the porous sintered body, and sepiolite volatilizes the interstitial water in the channel by heating and exerts the characteristic of molecular sieve. Thus, by forming a gel and preparing phosphoric acid or a phosphate and a metal oxide as a binder, it is possible to sinter in a wide range of low temperature at 500 to 850 ° C. Furthermore, antibacterial action can be achieved by adding zeolite carrying calcium ions or copper ions or calcium phosphate or sepiolite.

That is, here, the oyster shell powder is provided with preferable characteristics for constituting the porous sintered body. The material of the oyster shell powder, with 80-90% inorganic substance composed mainly of CaO-P ₂ O ₅ -CaCO ₃ quality, the balance being organic substances mainly composed of various amino acids are used in pulverized into 100 mesh or less.

When oyster shells are heated (500 to 900), organic components and CO _{2 components} are volatilized and activated, and gas adsorption and hydrophilicity are remarkably increased. In particular, Ca ² + sites exposed as an interfacial function have bacterial immobilization properties (lipoteichoic acid, amino acid inclusions). Since the oyster shell has a structure in which inorganic components are anisotropically laminated, it becomes a short fiber when crushed. Also,
Clear whiteness by heating (Snow White N-9-5)
Present.

Further, sepiolite is used in order to make use of its excellent molecular characteristic. Sepiolite belongs to the phyllosilicates and has the general formula (Mg
₈ ) [Si ₁₂ O ₃₀ ] (OH) ₄ (OH ₂ ) 6 to 8H ₂ O, a three-layer lattice of silicic acid tetrahedron (SiO ₄ ) -hydrotalcite hexahedron (Mg center) -silicic acid tetrahedron Is one molecule unit, and since the vertex oxygens of the silicic acid tetrahedrons face each other alternately, the channels (pores 11.5 × 5.6) are alternated vertically and horizontally.
Å) is formed, and water molecules are coordinated in this channel, which has a molecular action. The specific surface area is 230 to 260 m ² / g, the water adsorption ratio is 1 to 1.2, and the oil absorption amount is 250 to 270 ml / 100 gr. In addition, Mg ² shows an ion exchange property, and C, E, and C are 20 meq / 100 g. Sepiolite is cleaved into fibrous fine particles (length 10 μm or less, diameter 20 to 100 μm), which are dispersed in water to form a gel. This gel is highly viscous and has thixotropy.

The oyster shell powder and the sepiolite are mixed in a ratio of 20:80 to 80:20, and the total amount of the oyster shell powder and the sepiolite is 60 to 80% by weight. The ratio is 35:65 to 65:35. If there is little oyster shell powder, gas adsorption and hydrophilicity will be poor,
If there is little sepiolite, the moldability will be poor.

Phosphoric acid or phosphate is used as a binder and has hydrophilicity between the oyster shells and sepiolite, which are the main raw materials, and has a temperature range of 500 to 850 ° C. at which the sepiolite crystal structure does not collapse. This is to sinter in a wide range of low temperature range. As the phosphate, H ₃ PO
₄ , CaHPO ₄ , MgHPO ₄ , Al (H ₂ PO ₄ ) ₃ are used. It should be noted that the addition of 15 to 30% by weight of phosphoric acid or phosphate is optimal, and if it is less than that, the binding between oyster shell and sepiolite will be poor, and if it is more than that, the amount of oyster shell and sepiolite as the main raw material will be added. Is reduced and the skeleton becomes brittle.

The addition of the metal oxide is used as an auxiliary material for the binder of phosphoric acid or phosphate. That is, phosphoric acid or phosphate takes the form of P ₂ O _{5 at} high temperature, but P ₂ O ₅ has a poor water resistance due to lack of O in the O / P ratio. In order to prevent this and improve strength, polyvalent metal oxide titania (Ti
O ₃ ) or alumina (Al ₂ O ₃ ) or the like is added.
It is because the addition amount of the metal oxide is appropriately 0 to 10% by weight, the strength is inferior when the amount is small and the sintering temperature is high when the amount is more than that.

The reason why the zeolite carrying silver ions or copper ions or calcium phosphate or sepiolite is added is to impart antibacterial properties to the product having a hygroscopic effect. What is used is a zeolite carrying silver ions or copper ions, an apatite material carrying a silver complex salt (CaO-P ₂ O ₅ material), sepiolite previously substituted with Ag +, or the like. The proper addition amount is 0.2 to 2% by weight, and if it is less than that, the antibacterial property becomes poor, and if it is more than that, the cost becomes high.

Further, the compounding method in the manufacturing method differs depending on the molding method, and when it is subjected to the pressure molding method,
After weighing each composition, water and an organic binder such as CM
C, PVA, an acrylic substance is added in an appropriate amount and thoroughly mixed with a ball mill or the like, and then granulated at 100 to 150 to be used, or the main raw material is dispersed in water to form a solid content of 3 to 20
% Gel, add other binders, binder aids, antibacterial agents, etc. and organic binders while stirring with rotation, and then prepare a molding compound by a method such as granulating with a spray dryer etc. and pressurizing. Mold by pressing.

In the casting method utilizing the thixotropic property, the main raw material is deflocculated into a slurry and the thixotropic action of sepiolite is utilized. That is, when the solid separation degree is 3 to 10%, the slurry exhibits a high viscosity in a stationary state, but exhibits a rheological behavior that easily becomes a fluid state when stirred. A predetermined amount of another blended raw material is added to the slurry of the main raw material under stirring, and while continuing stirring, the slurry is cast into a mold for molding. By slowly heating and drying, the moisture is volatilized to obtain a solidified molded product. This method is suitable for obtaining a material having a large porosity and various shapes.

Firing is carried out in a heating furnace, and is 50 to 100.
The temperature is raised to the sintering temperature at a heating rate of ° C / hour, and the sintering temperature is maintained for 1 to 2 hours to complete the sintering. The sintering temperature is 500 to 8 in consideration of composition, molding method, shape, size, strength and the like.
Determine within the range of 50 ° C.

The structure of the porous sintered body according to the present invention has a secondary porosity formed by the fibrous powder of oyster shell and the fibrous fine powder of sepiolite being reciprocally formed, and the molecular sieve existing inside the sepiolite powder. A porous sintered body having a porosity of 25 to 60%, which is composite with primary pores, and the porous body structure is remarkably hydrophilic, and has a humidity controlling function of adsorbing and dehydrating a large amount of moisture. Given to. Moreover, not only the humidity control effect, but also the molecular activity of sepiolite,
The oyster shell powder has chemical activity such as adsorption of polar organic substances.

In order for the functions of these porous sintered bodies to be exhibited, firing is carried out in a state where the active calcination pore structure of the oyster shell, which is the main raw material, and the molecularly crystalline structure of sepiolite are maintained. The union needs to be constructed. For this purpose, it is necessary to sinter at 850 ° C. or lower, and in the present invention, the consolidating action of the phosphate used in the binder fulfills the requirement. In particular, the material of the oyster shell is calcium salt or calcium phosphate salt, which chemically bonds with the phosphates of the binder, and therefore has a great effect on the sintering at 850 ° C or lower.

Further, even when an antibacterial material is added, when silver ion-supported zeolite, calcium phosphate, sepiolite, etc. are heated at a high temperature, the silver ions sinter with the carrier to stabilize and lose the antibacterial action. In the sintering temperature range of the present invention, the active state can be maintained.

[0022]

EXAMPLES The details of the present invention will be described below with reference to examples. The composition shown in Table 1 is sepiolite (manufactured by Mizusawa Chemical Co., Ltd.) in the form of fine powder of 5 μm or less, oyster shell powder of 150 mesh or less (produced in Miyagi prefecture), metal oxide of TiO ₃ or Al ₂ O ₃ , and clay mineral. Example 1 to 10 by weighing
200 parts by weight of water is added to 100 parts by weight of these raw material blends, and the mixture is also wet-ground for about 3 hours in a ball mill and mixed. Then phosphoric acid (H ₃ PO ₄ , concentration 80%) or first
A solution of aluminum phosphate (Al ₂ H ₂ PO ₄ , concentration 70%) was added in an amount shown in Table 1, stirred and mixed to fill the slurry in a refractory container, dried at 100 ° C., and the water content was adjusted to 3-5. % Cake. This is passed through a 100 mesh net to make granules. Using the granules, press molding by press molding
A plate-shaped molded product of × 100 × 20t is obtained.

[0023]

[Table 1]

This molded product was dried at 100 ° C. for 12 hours, then placed in an electric furnace and heated at a heating rate of 80 ° C./hr, and the sintering was completed within the predetermined sintering temperature holding time shown in Table 1. To do. Table 2 shows physical properties and color tones of the obtained sintered bodies of Examples 1 to 10.

[0025]

[Table 2]

Table 3 shows the results of measuring the changes with time of the moisture absorption amount and the moisture release amount of the sintered bodies of Examples 1, 3, 4, 6, and 9. In addition, the gas adsorption characteristics of ammonia and hydrogen sulfide were compared with those of Examples 1, 4, and 9 by the static method.
The results are shown in Table 4 as measured with a test container volume of 1000 ml. According to this, good dehumidification hygroscopicity and gas adsorbability were confirmed.

[0027]

[Table 3]

[0028]

[Table 4]

Next, as Examples 11 to 14, sepiolite, alumina, oyster shell powder, pyroferrite, etc. were weighed out so as to have the composition shown in Table 5, and their raw material blends 1
200 parts by weight of water is added to 00 parts by weight and mixed in a ball mill for about 3 hours. This mixture was transferred to a tank equipped with a stirrer, and 15 to 30 parts by weight of aluminum monophosphate solution,
Further, 300 parts by weight of water is added to adjust the pH to 8-9 to prepare a gel-like slurry.

[0030]

[Table 5]

The viscosity of this slurry was 30 with a rotational viscometer.
It is 420 c.ps at rpm and 310 c.ps at 60 rpm. This slurry was cast into a hollow pipe type resin mold having an outer diameter of 100 mm, an inner diameter of 80 mm and a height of 10 mm, heated in a drying chamber at a temperature of 80 ° C. for 2 hours, removed from the mold, and heated by an electric furnace at a temperature of 80 °. C
/ Hr and hold at the temperatures shown in Table 5 to complete the sintering. Table 6 shows the shrinkage rate, physical properties and color tone of the sintered body.
Shown in According to this, all were good porous bodies with no defects.

[0032]

[Table 6]

Examples 15 to 19 are methods for producing a porous sintered body to which an antibacterial material is added. Commercially available Ag-zeolite (Ag
+ 1% supported zeolite), or commercially available Ag-apatite (Ag + 1% supported apatite), and Ag-sepiolite (manufactured by Otake Serum Co., Ltd.) in the composition of Table 7, Example 1 from its preparation to firing
It carried out by the same operation as -10. Incidentally, Ag-sepiolite (supporting Ag ions on sepiolite) is carried out by a conventionally known ion exchange method, and the ion exchange capacity of sepiolite is 20 meq / 100 g, and Mg ions in the tissue are A
Replace with g. The method is to add sepiolite to an aqueous solution of silver nitrate (AgNO ₃ ) adjusted to 0.3% by weight,
Ag-sepiolite is obtained by stirring for 4 hours, filtering, washing and drying. Table 8 shows the physical properties and color tone of the obtained sintered body.

[0034]

[Table 7]

[0035]

[Table 8]

The sintered bodies of Examples 15 to 19 were ground to a particle size of 1 μm.
In addition 0.01 wt% phosphate buffer as the following powder m, and then those was measured the cell suspension was added antimicrobial E. coli were both beginning 3.0 × 10 ^5, 1
As a result of measuring the number of bacteria after 2 hours, no bacteria were detected.

[0037]

EFFECTS OF THE INVENTION According to the present invention, the porous sinter composite of oyster shell powder and sepiolite exhibits hydrophilicity, has a humidity control function of adsorbing and desorbing a large amount of moisture, and is a polar substance of oyster shell. It has an absorption effect and a chemical activity such as molecular activity of sepiolite, and is suitable for use as an interior building material or as a purification material for various gases and liquids.
Further, in claim 2, the antibacterial property is retained by the addition of zeolite carrying calcium ions or copper ions, calcium phosphate or sepiolite.

[0038] According to claim 3 of the method of the present invention, the porous sintered body has a binding matrix of 500 to 850 ° C due to the mutual binding of phosphoric acid or phosphate and oyster shells.
It has a great effect that it can be easily sintered at low temperature. According to the fourth aspect, since a highly viscous gel state can be obtained by adding water to the raw material mixture and stirring, molding by casting can be easily performed.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B01J 20/10 B01J 20/10 B 20/18 20/18 E C04B 38/08 C04B 38/08 D (72) Inventor Haruka Ogawabayashi Technical Research Institute Co., Ltd. 4-640 Shimoseido, Kiyose-shi, Tokyo (72) Inventor Ichiba Mitani 4-640 Shimoseito Engineering Co., Ltd., Kiyose-shi, Tokyo (72) Inventor Noboru Izawa Ichiro 136 Shiogusa-cho, Seto-shi, Aichi Prefecture Otakechem Ram Co., Ltd. (72) Inventor Masayuki Goto 136-Shiogusa-cho, Seto-shi, Aichi Prefecture Otakechem Ram Co., Ltd. (72) Kio Takayanagi 136-Shiogusa-cho, Seto-shi, Aichi Prefecture Lam Co., Ltd. (72) Inventor Tadashi Ozeki 136 Shiogusa-cho, Seto City, Aichi Prefecture Otakechem Lam Co., Ltd.

Claims (4)

[Claims] 1. A porous sintered body comprising oyster shell powder, sepiolite, phosphoric acid or phosphate, and a metal oxide. 2. A porous sintered body composed of oyster shell powder, sepiolite, phosphoric acid or phosphate, a metal oxide, and zeolite or calcium phosphate or sepiolite carrying silver ions or copper ions. 3. The composition is wt%, the ratio of oyster shell powder to sepiolite is 20:80 to 80:20, the total amount of oyster shell powder to sepiolite is 60 to 80%, phosphoric acid or phosphate. 15-30%, titanium oxide or alumina 0
-10%, zeolite carrying calcium ion or copper ion or calcium phosphate or sepiolite 0.2-
Mix 2% raw material mix, mold, then 500
A method for producing a porous sintered body, which comprises sintering at ˜850 ° C. 4. The method for producing a porous sintered body according to claim 3, wherein water is added to the raw material mixture and the mixture is stirred to form a highly viscous gel, which is poured into a mold and molded.