JPH03215314A - Method for producing zeolite composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a sinterable zeolite composition by low temperature calcination.

[Problems to be solved by conventional technology and invention]

I. C. As the electrical insulator used in electronic components such as packages, sintered bodies of inorganic powders such as alumina are most widely used from the viewpoint of electrical and mechanical properties. Recently, the sintered body has been produced 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 to produce an electrical insulator with a circuit printed thereon. It is often obtained using a technique called cofire, which uses a body material. However, since sintering of inorganic powders generally requires high temperatures, only expensive electrically conductive materials that can withstand the high firing temperature κ can be used. For example, alumina powder is sintered at a sintering temperature of 1,500°C or higher, so if you try to use the alumina powder to obtain a sintered body with an electrical circuit baked in using the cofire technology, Mo,
There are circumstances that require the use of expensive electrically conductive substances such as Mn and W. Moreover, these materials have a defect in that they are not necessarily satisfactory in terms of electrical conductivity.

For this reason, Ag. Au, C.U.
The production of sintered bodies that can be cofired has been studied. One of the inventors of the present invention also published, for example, JP-A-1-1-000
In the <So publication, a method was proposed in which a specific calcium-type zeolite powder was molded and the molded product was fired at a temperature of 1000° C. or lower to obtain an anorthite-based sintered body. 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.

However, in order to obtain a high-density sintered body as close as possible to the theoretical density, the anorthite-based sintered body has a very narrow firing temperature range, making temperature control during firing difficult for industrial purposes. It has its drawbacks. For example, the above-mentioned calcium type zeolite will not sinter if the temperature during firing is low, and if the inverse κ is too high, air bubbles will be trapped in the sintered body, foaming and expansion will occur, and the yield will deteriorate. For this purpose, the firing temperature must be controlled within an extremely narrow range of, for example, 880°C to 900°C.

The above-mentioned drawbacks are not limited to anorthite-based sintered bodies, but also exhibit the same tendency when used with other alkaline earth metal aluminosilicate sintered bodies. Therefore, expanding the allowable range of firing temperature during the production of alkaline earth metal aluminosilicate sintered bodies is an important technical issue in industrial production.

[Means to solve the problem]

The present inventors have conducted research to widen the allowable range of firing temperature when zeolite is fired at a low temperature. As a result, the inventors found that the above object could be achieved by selecting a specific zeolite and blending boron oxide with it in the presence of water, and completed the present invention.

That is, the present invention proposes (+) general formula (1) and ζ as (iM1O・jM22O)・AAt2OB・mSi02
・nH2O (1) (wherein M1 is an alkaline earth metal ion, M2 is an alkali metal ion or ammonium ion, and i + j = 1 and j = 0 to 0.15,
t=0.9 to 1-1+m-1-5 to 2.5, and n is a number of 0 or more. ) When an amorphous calcined product obtained by calcining the alkaline earth metal type zeolite shown in (1) and (I1) boron oxide or a boron compound that can be converted to boron oxide by calcination are mixed in the presence of water, a special mold is produced. This is a method for producing a zeolite composition.

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

Zeolite is a well-known compound as an ion exchanger, and natural minerals or synthetic compounds are known as compounds in which the ion exchange portion can be substituted with abundant cations.

The raw material used in the present invention needs to be a zeolite represented by general formula (1). In the general formula (1), M1 needs to be an alkaline earth metal ion 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 it is not necessarily necessary to use only one type of these ions. may be configured. Particularly, among alkaline earth metal ions, calcium ions and magnesium ions are both present in the ion exchange part, and the Mg/Ca molar ratio is in the range of 0.05 to 1, preferably 0.05 to 0.5. Zeolite, which constitutes a part or all of the zeolite, is most suitable because it can widen the range of allowable temperatures during sintering and further lower the temperature during sintering by K. Moreover, in the general formula (1), M2 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 alkali metal ions or ammonium ions, it is preferable that the ion exchange part is contained in all or part of the zeolite due to its manufacturing method or ease of availability. Since zeolite composed of alkali metal ions is often converted into the zeolite represented by the general formula (1) by ion exchange, alkali metal ions often remain. However, the alkali metal ion or ammonium ion is not specified solely for the above reason, but also acts synergistically with the alkaline earth metal ion represented by M1, and has the role of lowering the temperature during sintering. Preferably, one or more alkali metal ions or ammonium ions coexist in the ion exchange portion of the zeolite. However, as the content of M2 in the general formula (1) increases, it becomes conductive, so that #in the general formula (1), j needs to be equal to or less than Oo15.

Furthermore, in the general formula (1), Si02 /At2Og(
A zeolite having a composition with a molar ratio exceeding 3 requires a firing temperature of a general K high temperature, for example, 1200° C. or higher, in order to obtain a sintered body thereof, and therefore does not meet the purpose of the present invention. Furthermore, similarly, if the ion exchange part of the zeolite is not substantially alkaline earth metal type, for example, if 80% or more of the ion exchange part is sodium type, the electrical insulation of the sintered body is not good. It cannot be used as a raw material for the present invention.

As is clear from the above explanation, the zeolite most preferably used for the purpose of the present invention, that is, to widen the sintering temperature range of zeolite and achieve sintering at a lower temperature, is represented by the following general formula (I1). It is a zeolite.

(kCaO-pMgOqM22O)・LAt2OB・m
SiO2・nH2O G[) In the above formula, M2 is an alkali metal ion or ammonium ion, k+p
+q=1, p/k=0.05~1 and q==Q~0.1
5, L=0.9~1.1, m=1-5~2
-5, and n is a number greater than or equal to 0. Moreover, M2 does not necessarily have to be one type of ion, and two or more types of ions may be mixed together.

Generally, whether or not a zeolite is represented by the general formulas (I) and G[) can be determined by elemental analysis. K can be easily determined by X@ diffraction. It is known that each type of special K alkaline earth metal zeolite has a characteristic diffraction angle, so the above determination is extremely easy. Typical alkaline earth metal zeolite X
To give an example of a line chart, Zeolite Type A has an X-ray diffraction chart of 29.8° at 2O. 2 7.0°. 23.9
and 21.5° K diffraction angle, and the zeolite type
It has a diffraction angle of 3.2°26.6° and 30.9°K.

In general, Zeolite SA, Zeolite X. This is a zeolite obtained by ion-exchanging dismondite, dachinite, or an ion-exchange portion of these as required.

In addition, the amorphous calcined product obtained by calcining the zeolite, which is a component of the raw material of the present invention, has a smaller volume shrinkage during sintering than K when sintering zeolite, so it is often preferred. You can get hired. When obtaining a sintered body using the special K cofire technology, it is preferable to use a raw material form in which zeolite is first passed through an amorphous calcined product.

Conveniently, 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 by further calcination at a higher temperature. Once the crystalline substance K is formed, a high temperature of 1200°C or higher is required to obtain a sintered body thereof. The conditions for the phase transition of the zeolite to an amorphous calcined product vary somewhat depending on the type of zeolite, but in general, an amorphous calcined product is obtained by calcining at a temperature of 750°C to 900°C for 1 to 5 hours. I can do it.

As is clear from the above description, in order to obtain a non-quality 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 and calcinate powders such as alumina, silica, calcia, etc., as required, as long as the composition ratio of the zeolite is not significantly exceeded.

Zeolite, which is a component of the raw material of the present invention, or the amorphous calcined product obtained by calcining the zeolite can be used as a powder of the required particle size.In general, commercially available granular products can be used as they are. However, it is preferable to use a 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 being able to not only lower the sintering temperature but also greatly improve the sintering temperature range by incorporating 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 calcination.

More specific examples of boron oxide and boron compounds that are preferably used because they are readily available are as follows. That is, for example, boron trioxide. Boron oxide such as boron dioxide: orthoboric acid. Boric acids such as metaboric acid and tetraboric acid; boron nitride; 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 0.1 to 2 Owt% as B2O3, preferably 0.5 to 10wt%.
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, the mixing is not sufficient, 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 adjusted. This is not desirable because the tolerance range is not widened.

It is preferable to add an acid or an alkali to the water used for mixing, and in particular, add ammonia to the water used for mixing.
H=8.0-12.0-preferably pH=9-0-
It is preferable to adjust K to a range of 11.0 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, K is as follows: (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.

■ Dissolve boron oxide or a boron compound 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 K in water, and this is mixed with an aqueous solution in which boron oxide or a boron compound is dissolved.

The following methods are adopted.

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

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

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 zeolite. Although this temperature cannot be determined unconditionally because it varies depending on the type of boron oxide or boron compound, the 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 specific method of molding and firing is as follows.

The shape of the molding may be determined in advance according to the shape of the object, taking into account the volumetric shrinkage during firing, and may be selected from rod-like, cylindrical, sheet-like, etc. without particular limitation. Further, as the molding method, molding machine, etc., known methods and machines can be used. The most common method is to put the zeolite composition into a specific frame K and mold it with or without pressure, or to mold it into a green sheet using a doctor blade. For these moldings, the zeolite composition obtained in the present invention may be used, and a binder may be used as necessary. As the binder, any binder known to be used during molding and firing of ceramics can be used without being limited to %K. Examples of typical binders that are suitable for general use include polyvinyl butyral and polyvinyl alcohol. It is an organic polymer compound such as polymethyl methacrylate.

When the above-mentioned molded product is fired, it becomes a sintered body of alkaline earth metal aluminosilicate.

The firing temperature depends on the type of boron oxide or boron compound, the blending ratio, the content of impurities, etc.
cannot be specified, but it is generally suitable to select from a temperature range of 800°C to 1000°C, preferably 850°C to 950°C. In K of the present invention, by blending boron oxide or a boron compound, the allowable temperature range for firing zeolite or an amorphous calcined product of the zeolite is greatly expanded, so the temperature at which the obtained sintered body has a sufficiently high K density is obtained. It is preferable to determine the temperature in advance before firing. Although the firing time is influenced by the firing temperature, it is suitable for general K to be selected from the range of 60 minutes to 20 hours, preferably 1 to 10 hours.

When the above-mentioned firing temperature is relatively low t4, although sufficient densification is achieved, crystallization may not be sufficient. In order to increase the mechanical strength of the resulting alkaline earth metal aluminosilicate sintered body, the higher the crystallinity, the better. Therefore, if the obtained sintered body is insufficiently crystallized, it is preferable to perform densification by sintering and then raise the temperature to a temperature sufficient for K crystallization or higher to achieve sufficient crystallization. The temperature sufficient for crystallization depends on the proportion of the boron compound and the amount of impurities, so it is a good idea to check it in advance.In addition, the above-mentioned calcination should proceed sufficiently in an oxygen atmosphere, for example, in the air. However, when firing cofire or the like and the printing material does not like an oxygen atmosphere, the firing may be carried out under an inert atmosphere such as nitrogen or carbon gas depending on the required K.

The obtained sintered body differs depending on the type of zeolite used as a raw material. For example, when calcium-type zeolite is used as a raw material, the obtained sintered body is an anorthite-based sintered body, and when magnesium-type zeolite is used, a cordierite-based sintered body is obtained, (.Ca #Mg
) type zeolite, an anorthite + cordierite sintered body is obtained.

The crystal forms of these sintered bodies are known depending on the type of alkaline earth metal aluminosilicate, so x
This can be confirmed by 1m diffraction. For example, anorthite has 2O in the X-ray diffraction chart K of 28.2~
27.6.24.2-23.8° and 22.2-21.
A unique peak appears in 6, and the cordierite is the same (1 0.3°.21.6°.26.5°.28.3
Characteristic peaks appear at 29.4° and 29.4°.

When producing an alkaline earth metal aluminosilicate sintered body using the zeolite composition obtained in the present invention as a raw material, conventionally known low-temperature fired ceramics are used for the purpose of increasing the mechanical strength of the sintered body. Application of the inorganic filler addition means used in the present invention can be freely selected.

However, the proportion of the inorganic filler added is preferably limited to a maximum of 30% by weight in order to maintain good properties of the resulting fired product. Further, as the inorganic filler, any known material for the above purpose can be used without being limited to %K. Examples of typical materials that are generally suitable for use are alumina,
Cozy light. Forsterite, mullite. Al in quartz etc.

〔effect〕

In calcination of the zeolite composition obtained by the method of the present invention, the permissible range of calcination temperature to obtain a high-density alkaline earth metal aluminosilicate sintered body is greatly expanded, making it easy to control the calcination temperature. . Therefore, even in industrial implementation, uneven sintering etc. are eliminated and the yield is dramatically improved. Furthermore, by using the zeolite composition obtained 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, and furthermore, it is possible to lower the temperature at which densification begins. Since the temperature can be lowered, firing at a lower temperature becomes possible. The sintered body obtained by firing the zeolite composition obtained according to the present invention 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 method K.

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

(1) Confirmation of sintered body crystals: Confirmation was made by xlm diffraction K and comparison with a known chart of alkaline earth metal aluminosilicate.

(III) Linear shrinkage rate C%) Length of the compact before firing (L1) and length after firing (L2)
were measured and calculated from the following formula.

(W>Crystallinity of sintered body (%)) From X-ray diffraction K, the height of the main peak of the crystal (for anorthite, 2θ = 2 8.1 5 ~ 27.62c'; for cordierite, 2θ = 28 .1 to 28.4) Calculated from K.

(V) Bending strength (Iwf/j) ．． Measured by method K of TIS R-1<SO1.

Example 1 Zeolite 4A (manufactured by Toyo Soda Kogyo ■, trade name: Toyo Builder), which is a sodium type zeolite, was ion-exchanged with a 10% calcium chloride aqueous solution, washed with water, and dried to obtain a calcium type zeolite (with the composition shown in Table 1). Zeolite 5A)
was prepared. The average particle size of this zeolite was 1.5 μm.

This calcium type zeolite was suspended in water, and aqueous ammonia was added to adjust the pH to 10.5. While stirring, 1
% by weight aqueous ammoniacal orthoboric acid solution was added dropwise.

There was almost no change in pH after dropping. Then, it was washed with water and dried. When this powder was analyzed, it was found that it contained B2O in the amount 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 into a sheet, and then fired for 3 hours to obtain an anorthite sintered body. As a result, Table 1 shows the sintering temperature range at which an anorthite sintered body having a theoretical density of 98% or more was obtained and the minimum sintering temperature at which the crystallization rate reached 100%.

The linear shrinkage rate of the sintered body and the deviation b were in the range of 16.0 to 18.0%. However, the theoretical density of one sintered body is 2.68.

Example 2 Boric acid-added zeolite 5 prepared in the same manner as Example 1
Pour into A and heat to 500℃ without calcining at 750℃ for 3 hours.
Rubber press molded with 114/clA, 30■φX5■
A molded body was obtained.

This molded body was subjected to K sintering in the same manner as in Example 1 to obtain an anorthite sintered body. The firing temperature at which the sample with the composition corresponding to ▲2 in Table 1 is packed and the theoretical density is 98% or more is 83
The temperature was 0 to 940°C, and the minimum firing temperature at which the -1 crystallization rate was 100% was 880°C. Also, the linear shrinkage rate is 3
It was 1%.

Example 3 Zeolite having the composition shown in Table 2 was prepared, and after pulverizing the powder, it was placed in a furnace and calcined at 850°C for 2 hours. This powder was dispersed in water and the pH was adjusted to 10 by adding aqueous ammonia.
OK adjusted. To this, an ammoniacal boric acid aqueous solution (1% by weight) was added and mixed so that the amount of 82O5 was 6% by weight. There was almost no change in pH after mixing. It was then dried and ground. Put this powder into mold K and heat at 500K.
Rubber press molded with f/+j, 30■φX5III
A molded body was obtained. This molded body was fired at various firing temperatures. As a result, regarding each zeolite shown in Table 2,
The permissible firing temperature range shown in the fa2 table and the minimum temperature at which crystallization reached 100% were obtained. Table 2 also shows the bending strength of each sintered body.

Claims (1)

[Claims] (1) (i) General formula (iM^1O・jM^2_2O)・lAl_2O_3・
mSiO_2・nH_2O (wherein M^1 is an alkaline earth metal ion, M^2 is an alkali metal ion or ammonium ion, i+j=1 and j=0 to 0.1
5, l=0.9 to 1.1, m=1.5 to 2.5, and n is a number of 0 or more. ) or an amorphous calcined product obtained by calcining the zeolite and (ii) boron oxide or a boron compound that can be converted to boron oxide by calcination, in the presence of water. A method for producing a zeolite composition.