JP2563982B2 - Method for producing anorthite-based sintered body - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an anorthite-based sintered body by firing at a relatively low temperature.

[Problems to be Solved by Prior Art and Invention]

As an electric insulator used for electronic parts such as IC packages, a sintered body of an inorganic powder such as alumina is most widely used in terms of electric characteristics; mechanical characteristics. Recently, such a sintered body is an electrically insulating material in which a circuit is baked by printing an electronic circuit on a molded body of an inorganic powder before sintering using an electrically conductive substance and then sintering the molded body. There are many cases obtained by the so-called core-ia technology.
However, since a high temperature is generally required to sinter the inorganic powder, there is a defect that only an expensive electrically conductive substance that can withstand the high firing temperature can be used. For example, since alumina powder requires a firing temperature of 1500 ° C. or higher, there is a unavoidable situation in which expensive electrically conductive materials such as Mo, Mn, and W are used, and these materials are electrically conductive. There were defects that were not always satisfactory. Then, a study was made on a sintered body which can be co-fired with Ag, Au, Cu, etc. to have good electric conductivity, and various low temperature fired bodies have been proposed. However, a manufacturing technique for a low-temperature sintered body that can be stably manufactured industrially and at low cost has not yet been established.

Therefore, an object of the present invention is to provide a technique for producing a sintered body by firing at a low temperature.

Another object of the present invention is to provide a sintered body that can be manufactured by the Coffayf technique using a metal material having good electric conductivity.

A further object of the present invention is to provide a sintered body suitable for a low temperature sintered substrate by providing a new manufacturing method.

[Means for solving the problem]

In order to achieve the above object, the present invention provides (I) a calcium-type zeolite having a composition of SiO ₂ / Al ₂ O ₃ of 2.5 or less, (II) an amorphous calcination product obtained by calcining the calcium-type zeolite, And (III) molding at least one powder selected from the group consisting of the calcium-type zeolite or a mixture of the amorphous calcinated product and an alkaline earth metal compound,
Next, there is provided a method for producing an anorthite-based sintered body, which comprises firing the molded product at a temperature of 1000 ° C. or lower.

The anorthite-based sintered body obtained in the present invention is a known one. Conventionally, anorthite has been obtained by calcining a mixture of calcium hydroxide and kaolin above 1400 ° C. However, in order to obtain a sintered body from the anorthite obtained in this way, a high temperature of 1400 ° C. or higher was required, and it was never a ceramic material for low temperature firing.

However, the anorthite-based sintered body provided by the present invention is
It can be produced by sintering at a low temperature, that is, 1000 ° C or lower, preferably 850 to 950 ° C, and is an excellent material as a substrate for electronic parts.

The raw material for the anorthite-based sintered body in the present invention needs to be selected from the group consisting of the following (I) to (III).

That is, (I) a calcium-type zeolite having a composition of SiO ₂ / Al ₂ O ₃ of 2.5 or less, (II) an amorphous calcined product obtained by calcining the calcium-type zeolite, and (III) the calcium-type zeolite or the It is at least one kind of powder selected from the group consisting of a mixture of an amorphous calcined product and an alkaline earth metal compound.

The most important factor in the present invention is that the raw material used for firing is SiO ₂
/ Al ₂ O ₃ is a calcium-type zeolite having a composition of 2.5 or less or a calcined product thereof. The calcium-type zeolite is a compound in which 90% or more of the ion exchange component is exchanged with calcium as described later. The ion exchange component is another cation, such as magnesium, barium,
Even if zeolite exchanged with sodium or the like is used, the object of the present invention cannot be achieved.

In the present invention, the above-mentioned calcium-type zeolite is a known compound, and as long as SiO ₂ / Al ₂ O ₃ has a composition of 2.5 or less, these known calcium-type zeolites can be used without particular limitation. In general, the determination as to whether or not the zeolite is a calcium-type zeolite can be made by X-ray diffraction. X of the calcium-type zeolite
The characteristic diffraction angles of line diffraction differ slightly depending on the type, and these charts are already known for each type. For example, the A-type calcium-type zeolite has diffraction angles of 29.8 °, 27.0 °, 23.9 ° and 21.5 ° at 2θ of the X-ray diffraction chart, and the X-type calcium-type zeolite also has 23.2 °, 26.6 ° and 2θ at 2θ. It has a diffraction angle of 30,9 °.

In general, zeolite is a compound well known as an ion exchanger, and a typical one that can be suitably used in the present invention can be generally represented by the following general formula (I).

(JCaO ・ kM _{2 / x} O) ・ lAl ₂ O ₃・ mSiO ₂・ nH ₂ O ・ ・ ・ (I) As is clear from the above formula, the calcium-type zeolite is a general term for zeolites in which 90% or more of the ion exchange component is occupied by CaO. In the general formula (I), the component represented by M is a small amount that can be ion-exchanged. Both cations are acceptable. Generally, the cation is most often sodium due to sodium-type zeolite, which is a typical raw material for producing calcium-type zeolite.

Further, the same sodium can be used even if it is exchanged with some or all of the other cations. Further, the cation is less likely to be disadvantageous in obtaining the anorthite-based sintered body which is the object of the present invention, and rather, a small amount of a cation component, for example, a sodium component of 0.1 to 2 wt.
% (The coefficient k in the general formula (I) corresponds to 0.005 to 0.1) may have an advantage that the firing temperature can be lowered. Therefore, as long as the ion-exchange component of the calcium-type zeolite contains 90% or more of the CaO component, the content of other components may be determined and used as necessary.

Representative examples particularly preferably used in the present invention are calcium-type zeolites such as zeolite 5A, zeolite X, dismondite, and dakulite. However, calcium-type zeolites with SiO ₂ / Al ₂ O ₃ greater than 2.5, such as mordenite (CaOAl ₂ O ₃ · 10SiO ₂ · 6H ₂ O)
Cannot be a raw material for the present invention.

Another one of the raw materials used in the present invention is an amorphous calcined product obtained by calcining the calcium zeolite. If the calcium-type zeolite is directly molded and then fired, the same volume contraction as that of general ceramics occurs. For the purpose of use in which the volume shrinkage is desired to be small, it is said that a calcined product obtained by temporarily calcining the calcium-type zeolite at a low temperature, for example, 800 to 900 ° C. to make it amorphous is used. Advantageously, the calcium-type zeolite undergoes a phase transition to an amorphous compound once by calcining at a low temperature, and further to an anorthite crystal when the calcining temperature is increased. The above-mentioned phase transition to amorphous is generally carried out by calcining at a temperature of 800 to 900 ° C. for 1 to 5 hours, and the amorphous calcined product exists in a stable state. Moreover, when the amorphous calcined product is molded and then calcined, a sintered body is obtained at a low temperature, and the volume shrinkage during the sintering is smaller than the volume shrinkage when the calcium-type zeolite molded product is directly sintered. Has the advantage. However, when the calcination temperature is raised when obtaining an amorphous substance of calcium-type zeolite, the phase transitions to the anorthite crystal as described above, and when the anorthite is formed, it can no longer be sintered at a low temperature of 1000 ° C. or less. Since a high temperature of 1200 ° C. or higher is required to obtain a sintered body, the object of the present invention cannot be achieved. Therefore, in order to obtain the above-mentioned calcium-type zeolite amorphous material, that is, an amorphous calcinated material, it is necessary to predetermine the conditions under which anorthite is not formed and calcine. Further, in the above calcination, mixing of powders of alumina, silica, and calcia and calcination is a mode that can be selected as needed, unless the composition ratio of the calcium-type zeolite is largely deviated. Furthermore, as one of the embodiments of mixing the above-mentioned amorphous calcination product with the alkaline earth metal compound added for the purpose of reducing the calcination temperature which will be described later, at the time of the above-mentioned calcination, the alkaline earth metal compound is added to the calcium-type zeolite. It is also possible to select a mode of premixing and calcination.

The calcium zeolite used as a raw material of the present invention or the amorphous calcined product obtained by calcining the calcium zeolite may be used as a powder having a required particle size. Generally, commercially available powdered products can be used as they are,
Preferably, the average particle size is 5 μm or less, more preferably 2 μm.
It is preferred to use a powder of μm or less.

Another mode of use of the raw material used in the present invention is a mixture of the above-mentioned calcium-type zeolite or an amorphous calcined product and an alkaline earth metal compound. The alkaline earth metal compound effectively acts to reduce the crystallization temperature of the anorthite-based sintered body. Further, silica, which is optionally added and mixed, contributes to the reduction of workability and dielectric constant, and is therefore often a preferred use mode. The alkaline earth metal compound is not particularly limited, and known compounds can be used. Generally, oxides or compounds that decompose into oxides during calcination or sintering are suitable. Generally, the compounds preferably used are oxides, hydroxides, nitrates, carbonates, etc., and alkaline earth metals include beryllium, magnesium, calcium,
Examples include strontium and barium. Of these alkaline earth metal compounds, magnesia and calcia are most preferably used from the viewpoints of handling property, price, and effect.

The above-mentioned alkaline earth metal compound is generally mixed as a powder, but the smaller the particle diameter is, the more preferable, and the powder having an average particle diameter of usually 5 μm or less, preferably 1 μm or less is preferably used.

Furthermore, the amount of the alkaline earth metal compound added varies depending on these types, the size of the particle size, the composition of the zeolite, etc. and cannot be unconditionally limited, but generally the alkaline earth metal compound is converted to an oxide. 5% by weight in the raw material, preferably 0.01 to 3% by weight, more preferably 0.1 to
It is sufficient to choose to include it in the range of 1.0% by weight.

In the present invention, it is necessary to form the raw material before firing the raw material. The shape of the molding may be determined in advance according to the shape of the target object in consideration of the volume shrinkage at the time of firing, and may be selected from rod-shaped, columnar, sheet-shaped, etc. without particular limitation. As the molding method and molding machine, known methods and machines can be used. Most commonly, the raw material powder is put in a specific form and molded under pressure or non-pressure, or green sheet molding by doctor blade. These moldings are
Further, the raw material powder may be used as it is, and a binder may be used if necessary. As the binder, those known to be used at the time of forming and firing known ceramics can be used without particular limitation. Typical binders that are generally preferably used are organic polymer compounds such as polyvinyl butyral, polyvinyl alcohol, and polymethyl methacrylate.

In the present invention, the molded product is then fired to obtain an anorthite-based sintered body. For the firing, low temperature firing, which is one of the most characteristic features of the present invention, is adopted. That is,
Firing in the present invention is generally less than 1000 ℃, preferably 85
Very low temperatures of 0-950 ° C are used. The firing time is not particularly limited, but it is usually preferable to select it in the range of 1 to 5 hours. Further, the above-mentioned baking proceeds sufficiently in an oxygen atmosphere, for example, in the atmosphere, but when the print material is unfavorable in an oxygen atmosphere during baking such as cofferia, an inert atmosphere such as nitrogen or carbon dioxide gas may be used as necessary. Can be carried out.

The fired body from which the present invention is obtained is an anorthite-based sintered body. It can be confirmed by X-ray diffraction that the sintered body is anorthite. That is, 2θ in the X-ray diffraction chart is 28.15 to 27.62 °, 24.18 to 23.79 °, 22,22 to 2
This can be confirmed by the appearance of anorthite-specific peaks in the respective 1.57 ° range.

The composition of the anorthite-based sintered body obtained in the present invention is generally represented by the following formula (II) (pCaO · qM _{2 / x} O) · Al ₂ O ₃ · 2SiO ₂ (II) (where, in the above formula, M Is a cation, x is a valence of the cation, p + q = 1, and q is 0 to 0.1). In addition, depending on the composition of the raw material, one component or two or more components are additionally present in excess of the above anorthite composition. In this case, such components are often present as glass in the grain boundaries of the sintered body. However, in general, if the firing temperature is too low or if the firing time is insufficient, calcium aluminate may form together with anorthite depending on the raw material composition.In such cases, either raise the firing temperature or lengthen the firing time. Can be used as a complete anorthite.

In producing the anorthite-based sintered body of the present invention, for the purpose of increasing the mechanical strength of the fired body, the inorganic filler addition means used in the conventionally known low temperature firing ceramics is applied to the present invention. Things can be freely selected. However, the addition ratio of the inorganic filler is a maximum of 30% by weight in order to keep the properties of the obtained anorthite sintered body good.
It is preferable to limit it to. In addition, as the inorganic filler, those known for the above purpose are not particularly limited and can be used.
Alumina, cordierite, forsterite, mullite,
Quartz or the like.

〔effect〕

According to the method of the present invention, 1000
It can be obtained by firing at a low temperature of ℃ or less. Further, when an amorphous calcination product obtained by calcination of calcium-type zeolite is used as a raw material, volume shrinkage due to sintering can be reduced. Furthermore, when an alkaline earth metal compound is mixed and used as a raw material, it is possible to further lower the crystallization temperature of the anorthite-based sintered body.

The anorthite-based sintered body obtained in the present invention has excellent electrical properties and mechanical properties, and can be suitably used as an electrical insulator. In particular, the effect of obtaining a sintered body having the above characteristics by sintering at a low temperature of 1000 ° C. or less makes an excellent contribution especially to the production of a wiring board in which a circuit is burnt by co-firing. Is.

〔Example〕

The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Various data measured in the following Examples and Comparative Examples were obtained by the following methods.

(I) Bending strength (kg / cm ² ) Three-point bending strength was measured in accordance with JIS R 1601 "Method for testing bending strength of fine ceramics".

(II) Sintered body density (g / cc) It was measured by the Archimedes method.

(III) Confirmation of anorthite crystal 2θ was 28.15 to 27.62 °, 24.18 to 2 by X-ray diffraction.
It was confirmed from the peaks appearing at 3.79 °, 22.22-21.57 ° that it was anorthite.

(IIV) Linear Shrinkage (%) The length (L ₁ ) of the molded product before firing and the length (L ₂ ) after firing were measured, respectively, and calculated from the following formula.

Example 1 Sodium-type zeolite Zeolite 4A (manufactured by Toyo Soda Kogyo Co., Ltd., trade name: Toyo Builder) was subjected to ion exchange with a 10% aqueous calcium chloride solution, washed with water and dried (0.03
A calcium-type zeolite (zeolite 5A) having a composition of Na ₂ O · 0.97CaO) · 0.96Al ₂ O ₃ · 1.85SiO ₂ was obtained. The average particle size of this zeolite was 1.5 μm. The X-ray diffraction chart of the obtained zeolite 5A is shown in FIG.

This zeolite 5A powder is crushed and put in a mold to 500 kg /
Rubber press molding was performed at a pressure of cm ² to obtain a molded body of 45 m / mφ × 5 m / mφ.

This molded body was put into an electric furnace and heated at a temperature rising rate of 5 ° C./min for 92 minutes.
The temperature was raised to a firing temperature of 0 ° C., and the temperature was maintained for 3 hours, then cooled and taken out.

The density of the obtained sintered body is 2.61 g / cc, (theoretical density
2.75 g / cc), the linear shrinkage was 30%, and the bending strength was 16 kg / cm ² .

Further, this sintered body was identified as anorthite by X-ray diffraction.

The X-ray diffraction chart of the obtained anorthite is shown in FIG.

Example 2 Zeolite X, manufactured by Nippon Kagaku Co., Ltd., trade name; Zeostar CX-100P (65% calcium concentration in the ion exchange part) was ion-exchanged with a 10% calcium chloride aqueous solution in place of the zeolite 5A of Example 1. It was washed with water and dried (0.05Na
₂ O.0.95 CaO) 1.0Al ₂ O ₃ .2.5SiO ₂ was used to obtain a sintered body by firing in the same manner as in Example 1 except that the calcium-type zeolite having the composition was used.

The average particle size of the calcium-type zeolite is 4μ.
m and its X-ray diffraction chart is shown in FIG.

The obtained sintered body had a sintered body density of 2.60 g / cc and a linear shrinkage ratio of 3
The bending strength was 0% and the bending strength was 14 kg / cm ² .

Further, this sintered body was identified as anorthite by X-ray diffraction.

Example 3 A sintered body was obtained in the same manner as in Example 1 except that the zeolite 5A was mixed with the alkaline earth metal compound shown in Table 1 at the ratio shown in Table 1 and fired. The obtained sintered body was identified as anorthite by X-ray diffraction.

Table 1 shows the sintered body density, linear shrinkage ratio, and bending strength of the obtained sintered body.

Example 4 In Example 1, before forming the zeolite 5A powder, the zeolite 5A powder was calcined at a temperature of 850 ° C. for 3 hours. The resulting powder was isomorphic by X-ray diffraction. After crushing the powder, it was molded and fired in the same manner as in Example 1 except that the firing condition was 920 ° C. for 3 hours to obtain a sintered body. The obtained sintered body was identified as anorthite by X-ray diffraction.

The obtained sintered body has a sintered body density of 2.60 g / cc and a linear shrinkage factor of 2.
The bending strength was 0.0% and the bending strength was 15 kg / cm ² .

Example 5 In Example 4, an alkaline earth metal compound shown in Table 2 was mixed with zeolite 5A at a ratio shown in Table 2 to give a second mixture.
A sintered body was obtained in the same manner as in Example 4 except that calcination and firing were performed under the calcination and firing conditions shown in the table.

The obtained sintered body was identified as anorthite by X-ray diffraction.

Table 2 shows the sintered body density, linear shrinkage ratio, and bending strength of these sintered bodies.

Example 6 Instead of the zeolite 5A of Example 5, a calcium-type zeolite having a composition shown in Table 3 obtained by ion-exchange of zeolite X in the same manner as in Example 2 was used, and calcined as shown in Table 3. A sintered body was obtained in the same manner except that calcination and firing were performed under the conditions and firing conditions.

Table 3 shows the sintered body density, linear shrinkage ratio, and bending strength of the obtained sintered body. Further, these sintered bodies were identified to be anorthite by X-ray diffraction.

Example 7 The calcined powder of zeolite 5A obtained under the calcining conditions shown in Table 4 according to the method described in Example 5 was obtained by using the alkaline earth metal compound shown in Table 4 in the calcined powder. It was added so as to have a ratio shown in Table 4 with respect to the amount, and after being dispersed and mixed in a mixed solvent of toluene, ethanol and butanol using a ball mill, polyvinyl butyral and a plasticizer as an organic binder were mixed. Then, it was defoamed and formed into a sheet by the doctor blade method. Next, the above sheet-shaped material was heated to remove the organic binder by firing, and then fired under the conditions shown in Table 4 and then cooled to obtain a sheet-shaped sintered body.

Table 4 also shows the sintered body density, linear shrinkage ratio, and bending strength of the obtained sintered body.

In addition, these sintered bodies were identified to be anorthite by X-ray diffraction.

No. 11 is a silica sol together with an alkaline earth metal compound (Catalyst Kasei Co., Ltd., trade name; Cataloid SI-30,
An average particle size of 0.1 μm or less) was used in combination with 3.4 wt%.

Comparative Example 1 Instead of the zeolite 5A of Example 1, the SiO ₂ / Al ₂ O ₃ ratio was 7.
A 0 to 8.0 zeolite (Nippon Kagaku Kogyo Co., Ltd., trade name: mordenite NM-100P) was used and calcined at a calcining temperature of 950 ° C. for 5 hours. As a result, no sintered body was obtained.

Comparative Example 2 31 g of kaolin (special grade reagent, manufactured by Wako Pure Chemical Industries Ltd.) and 10 g of calcium hydroxide (special grade reagent, manufactured by Wako Pure Chemical Industries Ltd.) were mixed and molded in the same manner as in Example 1 and baked. did. As a result, 1000 ° C., the calcined for 5 hours, the peak of anorthite in X-ray diffraction is not observed, gehlenite 2CaO · Al ₂ O ₃ · S
Only peaks of iO ₂ ) and pseudowollastonite (CaO ・ SiO ₂ ) were present. Moreover, sintering did not proceed, and only a porous material having a density of 1.95 could be obtained. For firing at 1300 ℃ for 5 hours,
Formation of anorthite could be confirmed by X-ray diffraction, and sintering proceeded, and a dense sintered body having a density of 2.60 was obtained.

[Brief description of drawings]

FIG. 1 and FIG. 3 are X-ray diffraction charts of the calcium-type zeolite used in Examples 1 and 2, respectively.
Further, FIG. 2 is an X-ray diffraction chart of the anorthite-based sintered body obtained in Example 1.

Claims (1)

(57) [Claims] 1. A calcium-type zeolite having a composition of SiO ₂ / Al ₂ O ₃ of 2.5 or less, (II) an amorphous calcined product obtained by calcining the calcium-type zeolite, and (III) the calcium-type Molding at least one powder selected from the group consisting of zeolite or a mixture of the amorphous calcinated product and an alkaline earth metal compound,
Next, a method for producing an anorthite-based sintered body, which comprises firing the molded product at a temperature of 1000 ° C. or lower.