JPH0416509A - Production of zeolite composition - Google Patents

Abstract

PURPOSE:To easily produce the stabilized-quality zeolite composition having a specified content of B by bringing an alkaline-earth metal type zeolite of specified composition into contact with B2O3 in the presence of water and drying the product without separating water. CONSTITUTION:An alkaline-earth metal type zeolite shown by the general formula of (kM<1>O.pM<2>O.qM O).lAl2O3.mSiO2.nH2O (M<1> and M<2> are different alkaline-earth metal ion, M<3> is an alkali metal or ammonium ion, k+p+q=1, p/k=0.05 to 1, q=0 to 0.15, l=0.9 to 1.1, m=1.5 to 2.5, m/l <=3 and n>=0) or the calcination product is used as the raw material. The raw material and boron oxide such as B2O3 or boric acid, etc., capable of forming boron oxide by calcination is mixed with water. The water is preferably controlled to about pH8-12. The mixture is dried as such without separating water. A stabilized- quality zeolite composition with its B content strictly controlled is obtained in this way. The composition is sintered at relatively low temp. to obtain a high-density sintered alkaline-earth metal aluminosilicate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a zeolite composition which becomes an alkaline earth metal aluminosilicate sintered body by low temperature calcination.

[Conventional technology]

1.C. Sintered bodies of inorganic powders such as alumina are most widely used as electrical insulators used in electronic components such as packages from the viewpoint of electrical properties, mechanical properties, etc. Recently, the sintered body is an electrical insulator in which a circuit is baked by printing an electric circuit using an electrically conductive substance on a molded body of inorganic powder before firing, and then sintering the molded body. It is often obtained using a technique called cofire. However, since sintering of inorganic powder generally requires high temperatures, there is a drawback that only expensive electrically conductive materials that can withstand high sintering temperatures can be used.

For example, alumina powder is sintered at a sintering temperature of 1500°C or higher, so if you want to use the alumina powder to obtain a sintered body with an electrical circuit baked in using cofire technology, Mo
There are circumstances that force the use of expensive electrically conductive substances such as Mn5-. Moreover, these materials have a defect in that they are not necessarily satisfactory in terms of electrical conductivity.

For this reason, research has been conducted into producing sintered bodies made of cocofire such as Ag, Au, and Cu, which have good electrical conductivity.

One of the inventors of the present invention also proposed, for example, in JP-A-1-10006.0, a method for obtaining an anorthite-based sintered body by molding a specific calcium-type zeolite powder and firing the molded product at a temperature of 1000°C or less. . The sintered body obtained by the above method is an excellent sintered body that can be sintered at a lower cost and at a lower temperature than conventional sintered bodies.

Further, in Japanese Patent Application No. 1-329638, the present inventors proposed a method in which boron oxide is mixed with a specific alkaline earth metal type zeolite and fired in order to widen the allowable range of firing temperature.

[Problem to be solved by the invention]

In the above method, the alkaline earth metal type zeolite and boron oxide are mixed in the presence of water in order to achieve uniform mixing. In this case, for subsequent molding, a method is generally adopted in which water is separated by a method such as filtration or centrifugation, and then dried.

However, when using an alkaline earth metal type zeolite containing two or more types of alkaline earth metals, when water is separated by filtration, boron oxide is transferred to the filter and remains in the alkaline earth metal type zeolite. A problem arose in that the amount of boron oxide was reduced. Moreover, since the amount of boron oxide remaining in the alkaline earth metal type zeolite depends on the filtration conditions, it has been difficult to control the amount of boron oxide remaining. This is a phenomenon that has not been observed in zeolites containing only one type of alkaline earth metal.

[Means to solve the problem]

The present inventors solved the above-mentioned problems and studied a method for adjusting the amount of boron oxide remaining in an alkaline earth metal type zeolite to an arbitrary value, and as a result, they arrived at the present invention.

That is, the present invention provides (i) general formula (1) % formula % (1) (wherein Ml and M2 are different alkaline earth metal ions, M'J is an alkali metal ion or ammonium ion, k + p 1q = 1', p/k =
0.05~l and "') q=Q-0,15, and l-
0.9~1.1 m=1.5~2.5 m/l
= 3 or less, and n is a number of 0 or more. ) or an amorphous calcined product obtained by calcining the zeolite and boron oxide or a boron compound that can be converted to boron oxide by calcination in the presence of water, and then the water is separated. This is a method for producing a zeolite composition characterized by drying without drying.

One of the most important requirements of the present invention is that the raw material used is a zeolite specified by the above formula (1).

Zeolite is a well-known compound as an ion exchanger, and the ion exchange part is substituted with various cations.
Natural minerals or synthetics are known. The raw material used in the present invention must be a zeolite represented by the above general formula.

In the general formula (r), Ml and M2 need to be different alkaline earth metal ions because of the need to lower the firing temperature. As the alkaline earth metal ion, ions such as magnesium, calcium, strontium, barium, etc. can be used, and two different types of ions among these ions together constitute M1 and M2 of the ion exchange section. Particularly, among the alkaline earth metal ions, calcium ions and magnesium ions are present together, and the molar ratio of Mg/Ca is in the range of 0.05 to 1, preferably 0.05 to 0.3, in a part of the ion exchange part. Alternatively, zeolite, which constitutes the entire composition, is most suitable because it can widen the allowable temperature range during calcination and further lower the temperature during calcination. Moreover, in the general formula (1), M3 is an alkali metal ion or an ammonium ion. Although it is not necessarily essential that the ion exchange part of the zeolite represented by the general formula (1) contains the alkali metal ion or ammonium ion, it is preferable that the ion exchange part is contained in all or part of the zeolite due to the manufacturing method or ease of labor. Since zeolite composed of alkali metal ions is often converted into zeolite represented by the above general formula by ion exchange, alkali metal ions often remain. However, the alkali metal ion or ammonium ion is not specified solely for the above reason (it acts synergistically with the alkaline earth metal ion represented by M1 above, and also serves to lower the temperature during firing). Preferably, one or more types of alkali metal ions or ammonium ions coexist in the ion exchange portion of the zeolite.

However, as the content of M3 in the general formula (I) increases, it becomes conductive, so in the general formula (1), q is 0.
It is preferably 15 or less.

In addition, in the general formula (1), 5i(h/A l z(h(
Zeolite having a composition with a molar ratio exceeding 3 generally requires a high temperature, for example, a calcination temperature of 1,200° C. or higher, to obtain a sintered body thereof, and therefore does not meet the purpose of the present invention. Furthermore, similarly, the ion exchange portion of the zeolite is not substantially alkaline earth metal type, for example, 80% of the ion exchange portion.
Those of the above sodium type do not have good electrical insulation properties of their sintered bodies, and cannot be used as raw materials for the present invention.

As is clear from the above description, the zeolite most preferably used to widen the range of zeolite sintering temperatures and achieve sintering at lower temperatures is the zeolite represented by the following general formula (II).

(kkao-pMgO・qM30) ・I A 1 z
oz-msioz, n)lzO(II) In the above formula, M
3 is an alkali metal ion or ammonium ion, k + p + q = l, p / = 0.05 to 1 and q = O
~0.15, l-0, 9~1.1, m =
1.5 to 2.5 and m/l=3 or less, and n is a number of 0 or more. Moreover, M3 does not necessarily have to be one type of ion, and two or more types of ions may be mixed together.

Generally, whether a zeolite is a zeolite represented by the above general formulas (I) or (II) can be easily determined by elemental analysis and X-ray diffraction. In particular, it is known that each type of alkaline earth metal-based zeolite has a characteristic diffraction angle, so the above determination is extremely easy. To illustrate the X-ray chart of a typical alkaline earth metal zeolite, zeolite type A has an X-ray diffraction chart of 2θ of 29.8°, 27.0°, and 23.9°.
and has a diffraction angle of 21.5°, and zeolite type X has a diffraction angle of 23
．． It has diffraction angles at 2°, 26.6° and 30.9°.

In addition, in general, zeolite 1-5A, zeolite .

Further, the amorphous calcined product obtained by calcining the zeolite has a smaller volumetric shrinkage during sintering than that of sintering the zeolite, and is therefore often suitably employed. Particularly when obtaining a sintered body by cofire technology, it is preferable to use a raw material form in which the zeolide is first passed through an amorphous calcined product.

Advantageously, the zeolite once undergoes a phase transition into an amorphous compound by being calcined at a low temperature, and undergoes a phase transition into a crystalline compound when further calcined at a high temperature. Once the crystalline material is formed, a high temperature of 1200 DEG C. or higher is required to obtain the sintered body.

The conditions for the phase transition of the zeolite to an amorphous calcined product vary somewhat depending on the type of zeolite, but generally it is 750°C.
An amorphous calcined product can be obtained by calcining at a temperature of ~900°C for 1 to 5 hours.

As is clear from the above description, in order to obtain an amorphous calcined product, it is necessary to select conditions that do not cause crystallization. Furthermore, since the amorphous calcined product exists in a stable state, it is necessary to determine the conditions for obtaining the amorphous calcined product in advance and calcinate the zeolite. Further, during the above-mentioned calcination, it is possible to mix powders such as alumina, silica, calcia, etc. and perform calcination as necessary, as long as the composition ratio of the zeolite does not deviate greatly.

The zeolite, which is a component of the raw material of the present invention, or the amorphous calcined product obtained by calcining the zeolite may be used as a powder with a required particle size. Generally, commercially available granular products can be used as they are, but it is preferable to use powder having an average particle diameter of 5 μm or less, preferably 2 μm or less.

Another component of the raw material used in the present invention is boron oxide or a boron compound that can be converted to boron oxide by calcination. The boron oxide or boron compound has the advantage of not only being able to lower the sintering temperature but also greatly improving the sintering temperature range by being blended with the zeolite or its amorphous calcined product. Although the mechanism by which the boron oxide or boron compound brings about these effects is not clear, the calcination temperature range of certain zeolites is only allowed to be around 10°C, whereas the zeolite obtained by the present invention For compositions, the effect of being able to take a firing temperature range of 50 to 150°C or more is an immeasurable industrial advantage.

As mentioned above, the boron compound used in the present invention may be any compound as long as it can be converted into boron oxide by firing. More specific examples of boron oxide and boron compounds that are generally easily available and are preferably used are as follows. That is, for example, boron oxides such as boron trioxide and boron dioxide; boric acids such as orthoboric acid, metaboric acid, and tetraboric acid; boron nitride; and boron compounds such as boron carbide are preferably used.

The blending ratio of the boron oxide or boron compound varies depending on the extent to which the allowable range of firing temperature is expanded, but is generally B20. as 0.1-20-t%, preferably 0.5-lowt
It is preferable to select from the range of %.

It is essential that the zeolite or the amorphous calcined product obtained by calcining the zeolite and the boron oxide or boron compound described above be mixed in the presence of water.

When the above-mentioned powders are dry mixed, they are not mixed sufficiently, and when the above-mentioned powders are mixed in an organic solvent, even if boron oxide or a boron compound is added, the firing temperature cannot be maintained. This is not desirable because the tolerance range is not widened.

It is preferable to add an acid or alkali to the water used for mixing, and in particular, add ammonia as the alkali to
) l=8.0-12.0, preferably pn=9, 0-1
It is preferable to adjust it to a range of 1.0 because the effect of adding boron oxide or a boron compound is significant.

Any method can be used to mix the above powders in the presence of water. Specifically, (1) Zeolite or an amorphous calcined product obtained by calcining the zeolite is dispersed in water, and boron oxide or a boron compound is added thereto and dissolved.

(2) Boron oxide or a boron compound is dissolved in water, and zeolite or an amorphous calcined product obtained by calcining the zeolite is added and mixed.

(2) Zeolite or an amorphous calcined product obtained by calcining the zeolite is dispersed in water, and mixed with an aqueous solution in which boron oxide or a boron compound is dissolved.

The following methods are adopted.

In the present invention, it is essential to remove water by drying without separating the zeolite or an amorphous calcined material obtained by calcining the zeolite from water by a method such as filtration or centrifugation. be.

If a method such as filtration or centrifugation is employed, the amount of boron oxide or boron compound remaining in the zeolite will be less than the blended amount and will vary, which is not preferable. As the drying method, any method such as drying with heat, drying with reduced pressure, drying with a desiccant such as phosphorus pentoxide or calcium oxide, etc. can be adopted.

In this way, a zeolite composition is obtained in which any given amount of zeolite or an amorphous calcined product obtained by calcining the zeolite, boron oxide, or a boron compound is uniformly mixed.

When uncalcined alkaline earth metal zeolite is used to obtain a zeolite composition, the alkaline earth metal zeolite is amorphized by calcining before shaping the obtained zeolite composition. It is preferable to use a calcined product in order to reduce the volumetric shrinkage caused by firing, which will be described later.

In this case, since boron oxide or a boron compound is added, the temperature at which an amorphous calcined product is obtained is generally lower than that in the case of calcining only zeolite. Although this temperature cannot be definitively specified because it varies depending on the type of boron oxide or boron compound, amount added, etc., phase transition is generally possible at 720° C. or higher.

The zeolite composition obtained by the method of the present invention is shaped by a known method and then calcined. The molding may be performed by known methods such as press molding or green sheet molding, and the firing may be performed at 800 to 1000°C for 30 to 20 hours. In this way, an alkaline earth metal aluminosilicate sintered body can be obtained.

〔effect〕

According to the method of the present invention, it is possible to strictly control the amount of boron or boron compound added to alkaline earth metal type zeolite. Therefore, it is possible to minimize rod unevenness during industrial production of the zeolite composition, and products with stable quality can be easily obtained in industrial implementation. Furthermore, by using the zeolite m-acid obtained in the present invention, the allowable range of firing temperature for obtaining a high-density alkaline earth metal aluminosilicate sintered body is greatly expanded, making it easier to manage the firing temperature. Become. Therefore, even in industrial implementation, sintering unevenness etc. are eliminated and the yield is dramatically improved. Further, according to the present invention, in addition to expanding the allowable range of densification temperature by sintering, it is possible to lower the temperature at which densification begins. Furthermore, since the present invention can lower the crystallization temperature of crystals, it becomes possible to perform firing at a lower temperature. The sintered body obtained by firing has excellent electrical properties and mechanical strength, and can be suitably used as an electrical insulating material. Therefore, the present invention can also be applied to a technique for firing an electrically insulating material on which a circuit is baked at a relatively low temperature with good dimensional stability.

〔Example〕

EXAMPLES In order to explain the present invention more specifically, Examples and Comparative Examples will be described below, but the present invention is not limited to these Examples. In addition, various data measured in the following Examples and Comparative Examples were obtained by the following methods.

(I) Sintered body density (g/cc) Measured by Archimedes method.

(n) Confirmation of sintered body crystal Confirmation was made by comparing with a known chart of alkaline earth metal aluminosilicate by X-ray diffraction.

(1) Linear shrinkage rate (%) Length of the compact before firing (Ll) and length after firing (L2)
were measured and calculated from the following formula.

L+ (IV) Crystallinity rate (%) of sintered body The height of the main peak of the crystal by X-ray diffraction (2θ = 28.15 to 27.62" for anorthite, 2
θ=28.1 to 28.4.

(V) Bending strength (kgf/mob2) Measured by the method of JIS R-1601.

Example 1 Zeolite 4A (manufactured by Tosoh ■, trade name: TOYOBUILDER), which is a sodium type zeolite, was ion-exchanged with a 10% calcium chloride aqueous solution, then ion-exchanged with a 10% magnesium chloride aqueous solution, washed with water, and dried. An alkaline earth metal zeolite having the composition shown below was prepared. The average particle size of this zeolite was 1.5μ steel.

For each of these alkaline earth metal type zeolites,
100 g was suspended in water, and aqueous ammonia was added to adjust the pH to 10.5. While stirring, a 10% by weight aqueous orthoboric acid solution dissolved in aqueous ammonia was added dropwise in the amount shown in Table 1, and then heated and dried without filtration. This powder was analyzed and the amounts contained as B z O3 are shown in Table 1.

This mixture was calcined at 750° C. for 3 hours and pulverized to obtain an amorphous powder. A binder was added thereto, the sheet was formed, and the sheet was fired for 3 hours to obtain a 7-no-1 site sintered body. As a result, the sintering temperature range (tolerable range) in which an anorthite sintered body with a theoretical density of 98% or more is obtained and the crystallinity rate is 10
The lowest firing temperature at which 0% was reached is shown in Table 1. The linear shrinkage rates of the sintered bodies were all in the range of 16.0 to 18.0%.

However, the theoretical density of the sintered body is 2.68.

The same procedure as in Example 1 was carried out, except that the amount shown in Table 2 was dropped, filtered and dried.

When magnesium was not added by ion exchange, the B2O3 content was stably high, but the allowable range of sintering temperature was higher (Table 2, Nakashina 11, Yang 2). When zeolite containing magnesium was used, a large amount of boric acid was lost during filtration, and as a result, the content of B, O, and B was small, and the E was also unstable and had poor reproducibility.

Example 2 Zeolite having the composition shown in Floor 2 of Example 1 was prepared, and the powder was pulverized and then calcined in a furnace at 850° C. for 2 hours.

Add ammonia water to 100g of this powder to make 1 ptt.
A 10% by weight aqueous orthoboric acid solution adjusted to 0.5
．． 9 g was added and mixed, and the water was evaporated by heating to dry the mixture without filtration.

When this powder was analyzed, it was found to be B20 in terms of zeolite anhydride. It contained 3.0% by weight.

This powder was put into a mold and rubber press molded at 500 kg/- to obtain a molded body of 30 m + *φ x 51 mm, which was fired at various firing temperatures. As a result, the theoretical density of 98
The firing temperature range at which a sintered body of 830 to 9% is obtained is 830 to 9.
The temperature is 30℃, and the lowest temperature at which the crystallization rate reaches 100% is 8℃.
The temperature was 70° C., and the bending strength was 20 kgf/am”.

Comparative example

Claims (1)

[Claims] (1) (i) General formula (kM^1O・pM^2O・qM^3O)・lAl_2
O_3・mSiO_2・nH_2O (in the formula, M^1 and M^2 are different alkaline earth metal ions, and M^3
is an alkali metal ion or ammonium ion,
k+p+q=1, p/k=0.05-1 and q=0-0
．． 1, l=0.9-1.1, m=1.5-2.5
Moreover, m/l=3 or less, and n is a number of 0 or more. )
After contacting the alkaline earth metal type zeolite shown by or an amorphous calcined product obtained by calcining the zeolite with boron oxide or a boron compound that can be converted to boron oxide by calcination in the presence of water, the water is separated. A method for producing a zeolite composition, characterized by drying without drying.