JP2002308646A - Wollastonite-based glass ceramic fired at low temperature and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wollastonite-based glass ceramic fired at a low temperature, which is obtained by using, as a raw material, waste glass (soda-lime glass) typified by used bottles and firing at a low firing temperature range and which has excellent electrical insulation and mechanical strengths. SOLUTION: The wollastonite-based glass ceramic fired at a low temperature is obtained by using a fine powder of soda-lime glass as a main raw material and firing at a temperature range of 825 to 900 deg.C, and contains wollastonite as a crystal, and as main components, SiO2 , CaO, Na2 O and B2 O3 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wollastonite-based low-temperature fired glass ceramic using soda-lime glass fine powder as a main material and a method for producing the same. It is used for an insulating material, for example, a circuit board of an electronic device or a small insulating component.

[0002]

2. Description of the Related Art As is well known, so-called "fine ceramics" having excellent electrical insulation properties and mechanical strength, which are widely used for circuit boards and small insulating parts of electronic equipment, etc., usually have a high temperature of 1200 to 1600 ° C. It has been fired. In the fine ceramics manufacturing industry, research and development to lower the firing temperature has been conducted since the 1980s to reduce product costs.
It is considered important from the standpoint of preventing global warming because it can contribute to reducing CO ₂ emissions.

That is, in the 1980s, as a ceramic which can be fired at around 1000 ° C., a composite of alumina and borosilicate glass (for example, lead borosilicate crystallized glass, alumino-calcium borosilicate crystallized glass and borosilicate glass) acid amorphous glass, etc.) or crystallized glass-based (e.g., _{cordierite-based: 2MgO · 2Al 2 O 3 ·} 5SiO 2 and β-
Spodumene system: such as _{Li 2 O · Al 2 0 3} · 4SiO 2) has been proposed.

In recent years, JP-A-10-120436 discloses that SiO ₂ : 40 to 70% by weight, CaO: 20 to 35% by weight, MgO:
11-30 _{wt%, Al 2 O 3: 0.5} ~10 wt%, SrO: 0
Wt%, ZnO: 0 wt%, TiO _2: 0 wt% and
A diopside-based low-temperature fired glass-ceramic material which can be fired in a temperature range of 850 to 950 ° C. using crystalline glass powder having a composition of Na ₂ O: 0 to 3% by weight has been proposed. No. the publication SiO _2: 40 to 70 wt%, Al ₂ O _3: 0~30 wt%, B ₂ O _3: 3~25 wt%, Na
₂ O: 0 to 5 wt%, K ₂ O: _0~5 wt%, CaO: 5 to 30
Anorthite-based or sinterable in a temperature range of 850 to 900 ° C. using a crystalline glass powder having a composition of 0 to 30% by weight, SrO: 0 to 30% by weight, and BaO: 0 to 30% by weight. Lastnite low temperature fired glass-ceramic materials have been proposed.

In order to obtain low-temperature fired fine ceramics having excellent electrical insulation properties and mechanical strength applicable to circuit boards and small insulating parts by firing at a temperature in the range of 850 to 900 ° C. As can be seen from the publication, a plurality of raw materials are combined at a predetermined compounding ratio and melted to synthesize a glass having a specific composition, and then the glass is finely pulverized (generally called “frit”). Must be used.

On the other hand, in the ceramic building material manufacturing industry such as tiles and blocks, as disclosed in Japanese Patent Application Laid-Open No. 2000-351664, waste glass (typically, soda-lime glass) represented by empty bottles is used as waste. In order to utilize from the point of view, fine powder obtained by pulverizing waste glass with clay or feldspar is compounded up to 70% by weight, and the compound is formed into a required shape, and the formed material is fired at 1000 ° C and tiled. And blocks are manufactured, and the tiles and blocks are commercially available.

[0007]

Recently, with the enforcement of the Containers and Packaging Recycling Law, the amount of waste glass such as empty bottles collected as municipal waste is rapidly increasing. In the production of glass bottles, about 70% of the raw materials are recycled glass waste, such as collected empty bottles, which are reused as raw materials for glass bottles. At present, colored glass and colorless glass are mixed), but most of them are discarded without being reused.

The inventor of the present invention has been conducting various studies for many years to establish so-called recycling technical means with the proposition of reusing waste glass discarded without being reused for many years.

In the fine ceramics manufacturing industry, the present inventor has found that when obtaining a low-temperature fired fine ceramics having excellent electric insulation and mechanical strength,
As described above, after combining and melting a plurality of raw materials at a predetermined mixing ratio to synthesize a glass having a specific composition, a glass fine powder (frit) obtained by pulverizing the glass is used. We paid attention to the fact that it was expensive.

Therefore, the present inventor uses waste glass (soda lime glass) represented by an empty bottle as a raw material,
The research was conducted to provide a manufacturing technique for obtaining a low-temperature fired fine ceramics having excellent electrical insulation and mechanical strength in a firing temperature range as low as possible.

The inventor of the present invention carried out a number of systematic experiments in order to achieve the above-mentioned technical object for waste glass (soda lime glass). When mixing and baking calcium fine powder and calcium metaborate fine powder
In the low temperature range of 825 to 900 ° C, it contains only wollastonite as a crystal, and a remarkable new finding that a wollastonite-based low-temperature fired glass ceramic having excellent electrical insulation and mechanical strength can be obtained. This achieved the technical task.

[0012]

The technical problem can be solved by the present invention as described below.

[0013] That is, the present invention comprises only wollastonite as a crystal obtained by firing at a temperature in the range of 825 to 900 ° C, using soda-lime glass fine powder as a main raw material, and containing SiO ₂ , CaO, Na _It is a wollastonite-based low-temperature fired glass ceramic mainly containing ₂ O and B ₂ O ₃ (Invention 1).

The present invention also relates to the first aspect of the present invention, wherein the amounts of the main components of SiO ₂ , CaO, Na ₂ O and B ₂ O ₃ are 85 parts by weight, 48 to 56 parts and 15 parts by weight, respectively. And 22 to 33 parts of wollastonite low-temperature fired glass ceramics (Invention 2).

The present invention also provides a method of mixing fine powder of a compound containing CaO and fine powder of a compound containing B ₂ O ₃ with fine powder of soda-lime glass, press-forming the mixture into a required shape, The product is calcined in a temperature range of 825 to 900 ° C., and contains only wollastonite as a crystal and wollastonite containing SiO ₂ , CaO, Na ₂ O and B ₂ O ₃ as main components. This is a method for producing a low-temperature fired glass ceramic (Invention 3).

The present invention also relates to the CaO according to the third aspect.
Is fine powder of calcium hydroxide, B ₂ O ₃
This is a method for producing wollastonite-based low-temperature fired glass ceramics in which the fine powder of the compound containing is calcium metaborate fine powder (Invention 4).

In the present invention, the compounding ratio of the fine powder of soda lime glass is 46.4 to 71.9% by weight, the compounding ratio of the fine powder of calcium hydroxide is 3.7 to 17.9% by weight, and
This is a method for producing wollastonite-based low-temperature fired glass ceramics in which the mixing ratio of calcium metaborate fine powder is 14.2 to 45.2% by weight (Invention 5).

The configuration of the present invention will be described in more detail as follows.

First, the wollastonite-based low-temperature fired glass ceramics according to the present invention is made of wollastonite (CaO.Si) as a crystal fired in a temperature range of 825 to 900 ° C.
O ₂ ) alone (see FIG. 1 below).

If the firing temperature is lower than 825 ° C., the densification by firing is insufficient, and the firing shrinkage is small, but the firing temperature is 850 ° C.
Exceeding the bulk density increases the density. If the sintering temperature exceeds 900 ° C., it will be melted.

The wollastonite low-temperature fired glass ceramics according to the present invention is mainly composed of SiO ₂ , CaO, Na ₂ O and B
₂ O ₃ with typical amounts of 85 parts by weight
Parts, 48 to 56 parts, 15 parts, and 22 to 33 parts, and each amount varies depending on the mixing ratio of each starting material.

The wollastonite low-temperature firing gas according to the present invention
The relative permittivity of glass ceramics is 5.0-6.3, volume resistivity
Is 1 × 10 at room temperature¹¹Ω · cm or more, 1 at 250 ° C
× 10 ⁶~ 1 × 10⁷Ωcm, and bulk density is 2.3-2.
5g / cm^ThreeThe bending strength is 80 to 105 MPa,
Electrical insulation and mechanical strength that can be used for small insulating parts
Is provided.

Next, each raw material used in the method for producing the wollastonite-based low-temperature fired glass ceramics according to the present invention and the mixing ratio thereof will be described.

As the soda-lime glass fine powder, a fine powder having a median diameter of 3 to 20 μm obtained by finely pulverizing waste glass such as an empty bottle made of soda-lime glass is used.

Examples of the compound containing CaO include fine powder of calcium hydroxide (Ca (OH) ₂ ), fine powder of calcium oxide (CaO), and fine powder of calcium silicate (CaO) having a median diameter of 3 to 20 μm.
・ MSiO ₂ .n H ₂ O) Fine powders and the like are used, but calcium hydroxide fine powders are preferred from the viewpoint of availability and handleability. By adding Ca components such as calcium hydroxide to SiO ₂ and CaO in the soda-lime glass fine powder, wollastonite crystals (CaO.SiO ₂ ) are precipitated. In addition, cementitious construction waste material can also be used as calcium silicate.

Compounds containing B ₂ O ₃ include calcium metaborate (CaO.B ₂ O ₃ .4H) having a median diameter of ₃ to ₂₀ μm.
₂ O) fine powder, boric anhydride (B ₂ O ₃ ) fine powder, colemanite (2CaO.3B ₂ O ₃ .5H ₂ O) fine powder, synthetic calcium borate (CaO.B ₂ O ₃ ) fine powder, etc. Although it is used, calcium metaborate fine powder is preferred from the viewpoint of availability and handleability. The B ₂ O ₃ component lowers the melting point of the glass phase and lowers the wollastonite deposition temperature. If B ₂ O ₃ is insufficient, debitrite (Na ₂ O.3CaO.6SiO ₂ ) crystals are precipitated from soda-lime glass.

The mixing ratio of each raw material is important. The mixing ratio of the soda-lime glass fine powder is selected from the range of 46.4 to 71.9% by weight, and if it is less than 46.4% by weight, calcium hydroxide and metaborate are relatively used. Since the proportion with calcium increases, the melting point of the glass decreases, and the fired body is easily softened and deformed. On the other hand, if the content exceeds 71.9% by weight, the glass phase remaining in the fired body increases and the mechanical strength is poor, so that it is not preferable. 50 from the viewpoint of waste utilization
It is desirable to mix at least 5% by weight, and in view of the physical properties of the desired product, 50.2 to 66.2% by weight is particularly preferred.

The mixing ratio of the calcium hydroxide fine powder is 3.7
If the amount is less than 3.7% by weight, the proportion of calcium metaborate relatively increases, so that the melting point of the glass is lowered and softening deformation or foaming is not preferred. When the content exceeds 17.9% by weight, the proportion of calcium metaborate relatively decreases.
It is not preferable because the melting point of the glass increases and the glass phase remaining in the fired body increases, resulting in poor mechanical strength. In view of the physical properties of the target substance, 50 to 17.9% by weight is particularly preferable.

The mixing ratio of the calcium metaborate fine powder is
It is selected from the range of 14.2 to 45.2% by weight. If it is less than 14.2% by weight, the proportion of calcium metaborate relatively decreases, so the melting point of the glass increases and the glass phase remaining in the fired body increases. However, it is not preferable because the mechanical strength is inferior. On the other hand, if it exceeds 45.2% by weight, the proportion of calcium metaborate relatively increases, so that the melting point of the glass is lowered and softening deformation or foaming is not preferred. In view of the physical properties of the target product, 15.9 to 39.8% by weight is particularly preferable.

By adding, as an aggregate, a finely pulverized ceramic material obtained by pulverizing ceramic powder such as alumina powder, a discarded insulator product or a discarded fired body product according to the present invention as an aggregate, the size of the fired body is reduced. Can be stabilized.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, representative embodiments of the present invention will be described.

Embodiment 1

Using a jet mill finely pulverized transparent glass bottle collected as municipal waste as soda-lime glass (a fine powder of 3 to 20 μm containing a large amount of particles having a median diameter of 6.4 μm), a fine powder of a compound containing CaO is used. Fine powder of calcium hydroxide (median diameter ₃ to ₂₀ μm) was used as the powder, and fine powder of calcium metaborate (median diameter ₃ to ₂₀ μm) was used as the fine powder of the compound containing B ₂ O ₃ .

To 57.5% by weight of the soda-lime glass fine powder, 14.9% by weight of calcium hydroxide fine powder and 27.6% by weight of calcium metaborate fine powder were added. After mixing in a wet ball mill using ethanol as a medium, the mixture was added to 20 mesh. And press-molded into a required shape at a pressure of 30 MPa to obtain a molded product.

Next, the molded article was heated at a rate of 200 ° C./h, held at a temperature of 800 to 900 ° C. for 5 minutes, and fired to obtain a fired body at a fired temperature of 800 ° C., a fired body at a fired temperature of 825 ° C., and a fired temperature. Fired body at 850 ° C (shown in Fig. 2
LT32), fired body at firing temperature 875 ° C, firing temperature 875
A sintered body at a temperature of 900 ° C. and a sintered body at a temperature of 900 ° C. were prepared.

The composition ratio of each fired body calculated from the raw material mixing ratio of the soda-lime glass fine powder, the calcium hydroxide fine powder, and the calcium metaborate fine powder is such that the SiO ₂ content is 48.13.
% By weight, 8.23% by weight of Na ₂ O, 31.32% by weight of CaO and B ₂
O ₃ is 12.33% by weight, and the total amount of SiO ₂ and Na ₂ O is 100
The composition ratio is about 85.00 parts by weight of SiO ₂ and about 15.00 parts by weight of Na ₂ O, about 56.00 parts by weight of CaO and about 22.00 parts by weight of B ₂ O ₃ .

Baking temperature 800 ° C, 825 ° C, 850 ° C, 875
X-ray diffraction of each fired body at 800 ℃ and 900 ℃
Wollastonite (CaO.SiO)_Two) And debit retry
To (Na _TwoO ・ 3CaO ・ 6SiO_Two ), But firing temperature 825 ℃
The above fired body is only wollastonite,
Stonite-based low-temperature fired glass ceramics have been obtained.
Was. Figure 1 shows the X-ray diffraction pattern of the 850 ° C fired body (LT32)
Show. In addition, a fully automatic X-ray diffractometer (model number:
MXP3: Mac Science Co., Ltd.)
S (Joint Committee on Powder Diffraction Standard
s) PDF (PowderDiffraction File) No.10-489 and N
o.29-372 and No.27-88 were used as reference patterns.

The mechanical strength, compactness and electrical insulation of the sintered body (LT32) at a firing temperature of 850 ° C. are determined by measuring the bending strength (MPa) according to JIS R1601, the water absorption (%) according to JIS C2141, and the bulk density. (G / cm ³ ), measured by relative dielectric constant and volume resistivity (Ω · cm) at 1 MHz. Table 1 shows the results.

[0039]

[Table 1]

The bulk density of the porcelain is 2.33 g / cm ³ , the bending strength is 80 MPa, the relative permittivity is 5.6, and the volume resistivity at room temperature is 10 ⁹
Ω · cm, volume resistivity at 250 ℃ 10 ⁶ , soda lime glass bulk density 2.47g / cm ³ , bending strength 50MPa
, Relative permittivity 6.8, volume resistivity at room temperature> 10 ¹² Ω · c
Since m and the volume resistivity at 250 ° C. are 10 ⁶ Ω · cm, electrical insulation and mechanical strength superior to those of porcelain are obtained.

The mixing weight ratio of CaO to SiO ₂ and
The mixing weight ratios of B ₂ O _{3 to} CaO are as follows: CaO / SiO ₂ = 31.32% by weight / 48.13% by weight = 0.65 and B ₂ O ₃ /CaO=12.33% by weight / 31.32% by weight in the fired body (LT32), respectively.
0.39, indicating that wollastonite crystals were precipitated at a low temperature and a high shrinkage rate was obtained in the fired body.

The wollastonite-based low-temperature fired glass ceramics, which is a 850 ° C. fired body (LT32), has a firing temperature as shown in FIG.
Densified at 850 ° C to maximize bulk density, firing temperature 900
The bulk density was almost constant up to ° C. Also, as shown in FIG.
Scanning electron micrographs (× 5000) after the etching treatment with 0% hydrofluoric acid for 20 seconds confirmed that countless fine needle-like wollastonite crystals were precipitated.

According to the present embodiment, 14.9% by weight of calcium hydroxide fine powder and 27.6% by weight of calcium metaborate fine powder are added to 57.5% by weight of soda-lime glass fine powder and mixed and fired. Some SiO ₂ , CaO, Na ₂ O and B ₂ O
The amounts of ₃ are 85 parts, 56 parts, 15 parts and 2 parts by weight, respectively.
A wollastonite-based low-temperature fired glass ceramic containing only wollastonite as a crystal and having excellent electrical strength and mechanical strength can be obtained at a firing temperature of 825 ° C. or higher for two parts.

A typical glass composition of a glass bottle generally used is 73.07% by weight of SiO ₂ , 1.93% by weight.
Al ₂ O ₃ , 0.03 wt% Fe ₂ O ₃ , 11.13 wt% CaO, 0.07 wt% MgO, 12.49 wt% Na ₂ O, 0.94 wt% K ₂ O, 0.32 wt% SO ₃ , 0.01 wt% TiO ₂ and others This waste glass bottle may be used, and in this embodiment, the waste glass bottle is used as soda-lime glass.

Further, a mixture of the crushed jet mill of the empty bottle, the calcium hydroxide powder and the calcium metaborate fine powder is converted into a fine powder having a median diameter of 3 to 20 μm containing a large amount of particles having a median diameter of 6.4 μm, and then treated. It may be.

Embodiment 2

In the same manner as in Embodiment 1, 60.2% by weight of soda-lime glass fine powder, 10.8% by weight of calcium hydroxide fine powder and 28.9% by weight of calcium metaborate fine powder were fired at the above firing temperatures (see FIG. 2). LT22) as shown
Soda lime glass fine powder 55.2% by weight, calcium hydroxide fine powder 5.0% by weight and calcium metaborate fine powder 39.8
By weight%, the fired body at each of the above firing temperatures (LT2 shown in FIG. 2)
3) was prepared, and fired bodies (LT33 shown in FIG. 2) at the above firing temperatures were manufactured using 52.9% by weight of soda-lime glass fine powder, 8.9% by weight of calcium hydroxide fine powder, and 38.2% by weight of fine powder of calcium metaborate. .

X-ray diffraction of each of the fired bodies indicated that only the wollastonite was obtained in the fired body at a firing temperature of 825 ° C. or higher, and a wollastonite-based low-temperature fired glass ceramic was obtained.

From FIG. 2 showing the relationship between the bulk density and the firing temperature of each of the fired bodies, all of the fired bodies at 850 ° C. have the highest density. The same mechanical strength as that of porcelain is obtained, and the electrical insulation property of porcelain is higher than that of porcelain.

Also, the mixing weight ratio of CaO to SiO ₂ and
The mixing weight ratios of B ₂ O ₃ to CaO were as follows: CaO / SiO ₂ = 28.24% by weight / 50.28% by weight = 0.56 and B ₂ O ₃ /CaO=12.88% by weight / 28.24% by weight in the fired body (LT22).
0.46. In the fired body (LT23), CaO /
SiO ₂ = 26.51% by weight / 47.26% by weight = 0.56, B ₂ O ₃ / CaO
= 18.51 wt% / 26.51% by weight = 0.70, in the sintered body (LT33), respectively CaO / SiO ₂ = 29.48 wt%
/45.35 _{weight% = 0.65, B 2 O 3} / CaO = 17.42 wt% / 2
In each case, wollastonite crystals were precipitated at a low temperature and a high shrinkage rate was obtained in the fired body.

[0051] Incidentally, the composition ratio of each sintered body was calculated from the raw material mixing ratio of the soda-lime glass powder and calcium fine powder and calcium metaborate powder hydroxide, in the sintered body (LT22), SiO ₂ is 50.28% by weight, Na ₂ O 8.
60% by weight, 28.24% by weight of CaO and 12.88% by weight of B ₂ O ₃
When the total amount of SiO ₂ and Na ₂ O is 100, the composition ratio is about 48.00 parts by weight of CaO and about 22.00 parts by weight with respect to about 85.00 parts by weight of SiO ₂ and about 15.00 parts by weight of Na ₂ O. a of B ₂ O _3, in the sintered body (LT23), SiO ₂ is 47.26 wt%,
8.08% by weight of Na ₂ O, 26.51% by weight of CaO and 18.5% of B ₂ O ₃
1% by weight, and the composition ratio of the total amount of SiO ₂ and Na ₂ O to 100 is about 85.00 parts by weight of SiO ₂ and about 15.00 parts by weight of Na.
Against ₂ O and CaO of about 48.00 parts by weight to about 33.00 parts by weight of B ₂
O ₃ , and in the fired body (LT33), 45.35% by weight of SiO ₂ , 7.75% by weight of Na ₂ O, 29.48% by weight of CaO, and B ₂ O ₃
And the total amount of SiO ₂ and Na ₂ O is 100, the composition ratio is about 85.00 parts by weight of SiO ₂ and about 15.00 parts by weight of Na ₂ O and about 56.00 parts by weight of CaO. About 33.00 parts by weight of B ₂ O ₃ .

Embodiment 3 FIG.

10.2% by weight of 60.2% by weight of soda lime glass
0.8% by weight of calcium hydroxide powder and 28.9% by weight of calcium metaborate powder are added and mixed in a dry planetary ball mill to form a mixture having a fineness of 3 to 20 μm containing a large amount of particles having a median diameter of 6.4 μm. A fired body was produced in the same manner as in Embodiment 1.

Also in this embodiment, the firing temperature is 825 ° C.
The above fired body was only wollastonite, and was a wollastonite-based low-temperature fired glass ceramic having the same effect as in the first embodiment.

The bending strength of each fired body at a firing temperature of 850 ° C. was 95 MPa, the water absorption was 0.0%, and the bulk density was 2.41 g.
/ Cm ³ , and the same mechanical strength as in the first embodiment is obtained.

[0056]

【Example】

Examples 1 to 9 and Comparative Examples 1 to 3.

As in the case of the first embodiment, the fired body of each of the examples and each of the comparative examples using the raw material mixture shown in Tables 2 and 3 using the ground glass of the waste glass bottle in the first embodiment as soda lime glass. Was prepared. Tables 2 and 3
The composition ratio of SiO ₂ , Na ₂ O, CaO and B ₂ O ₃ which is the composition of the fired body was calculated from the raw material mixing ratio of soda-lime glass fine powder, calcium hydroxide fine powder and calcium metaborate fine powder. % By weight, and the composition ratio where the total amount of SiO ₂ and Na ₂ O was 100 was indicated as the weight ratio of the prepared composition.

[0059]

[Table 2]

[0060]

[Table 3]

In Tables 2 and 3, the compounding ratio of the soda-lime glass fine powder, the calcium hydroxide fine powder and the calcium metaborate fine powder is shown as a raw material mixture, and the composition ratio of the fired body calculated from the compounding ratio is prepared. When the composition weight% and the total amount of SiO ₂ and Na ₂ O are 100
The composition ratio of the fired body in CaO and B ₂ O ₃ is shown as a blended composition part by weight.

In Examples 1 to 9, the firing temperature was 825.
C., 850.degree. C., 870.degree. C. and 900.degree. C. showed only wollastonite in the fired body, and a wollastonite-based low-temperature fired glass ceramic was obtained. In addition, firing temperature 85
The sintered body at 0 ° C. was the most dense.

The mixing weight ratio of CaO to SiO ₂ and
The mixing weight ratio of B ₂ O ₃ with respect to CaO in the fired body of Example 3 was CaO / SiO ₂ = 30.21% by weight / 53.73% by weight = 0.56 and B ₂ O ₃ /CaO=6.88% by weight / 30.21% by weight, respectively. =
0.23, and in the fired body of Example 4, CaO
/ SiO ₂ = 33.86% by weight / 50.92% by weight = 0.66, B ₂ O ₃ / Ca
O = 6.52% by weight / 33.86% by weight = 0.19;
In the fired body of CaO / SiO ₂ = 27.81% by weight
/42.73% by weight = 0.65, B ₂ O ₃ /CaO=22.16% by weight / 2
7.81% by weight = 0.80, and in the fired body of Example 7, CaO / SiO ₂ = 34.96% by weight / 45.58% by weight, respectively.
_{= 0.78, B 2 O 3 /} CaO = 11.67 wt% / 34.96 wt% = 0.3
3, and in the fired body of Example 8, CaO 2 / S
iO ₂ = 33.01% by weight / 48.08% by weight = 0.69, B ₂ O ₃ / CaO =
16.55% by weight / 33.01% by weight = 0.50, and in the fired body of Example 9, CaO / SiO ₂ = 31.33% by weight /
40.65 _{wt% = 0.77, B 2 O 3} / CaO = 21.08 wt% / 31.3
3% by weight = 0.67, and in each case, wollastonite crystals were precipitated at a low temperature, and a high shrinkage rate was obtained in the fired body.

On the other hand, the fired bodies of Comparative Examples 2 and 3 both contained devitrite. In addition, firing temperature 825
The bulk densities at ℃, 850 ° C, 870 ° C and 900 ° C did not change and were not densified. In Comparative Example 1, since the calcium hydroxide fine powder was not blended in the raw material blend, it was in a melt-foamed state and was not a wollastonite-based low-temperature fired glass ceramic.

[0065]

According to the present invention, waste glass (soda lime glass) is used, and calcium hydroxide fine powder and calcium metaborate fine powder are mixed with the soda lime glass fine powder at a specific blending ratio to reduce the temperature. By firing, it is possible to provide wollastonite-based low-temperature fired glass ceramics having excellent electrical insulation and mechanical strength for circuit boards and small insulating parts of electronic devices and the like. Glass can be reused.

Therefore, it can be said that the industrial applicability of the present invention is very high.

[Brief description of the drawings]

FIG. 1 is a graph showing an X-ray diffraction pattern of a wollastonite-based low-temperature fired glass ceramic according to Embodiment 1 of the present invention.

FIG. 2 is a graph showing the relationship between bulk density and firing temperature of wollastonite-based low-temperature fired glass ceramics according to Embodiment 1 of the present invention.

FIG. 3 is a scanning electron micrograph instead of a drawing showing the surface structure of the wollastonite low-temperature fired glass ceramics according to Embodiment 1 of the present invention at × 5000 magnification.

Continued on the front page F term (reference) 4G062 AA11 BB05 CC03 DA07 DB01 DC04 DC05 DD01 DE01 DF01 EA01 EB04 EC01 ED01 EE05 EE06 EF01 EG01 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FG01 FH01 FJ01 FK01 H01H01 GB01 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM28 NN32 QQ07

Claims (5)

[Claims] Claims: 1. Soda lime glass fine powder as a main raw material,
In addition, it contains only wollastonite as a crystal obtained by firing in a temperature range of 825 to 900 ° C., and contains SiO ₂ , C
A wollastonite-based low-temperature fired glass ceramic containing aO, Na ₂ O and B ₂ O ₃ as main components. _2. The amounts of the main components SiO ₂ , CaO, Na ₂ O and B ₂ O ₃ are 85 parts, 48 to 56 parts, 15 parts and 15 parts by weight, respectively.
2. The wollastonite low-temperature fired glass ceramic according to claim 1, wherein the amount is 22 to 33 parts. 3. A fine powder of a compound containing CaO and a fine powder of a compound containing B ₂ O ₃ are mixed with fine powder of soda-lime glass,
The mixture is press-molded into a required shape, and the molded product is subjected to 825 to
It contains only wollastonite as a crystal characterized by being fired in a temperature range of 900 ° C, and contains SiO ₂ , CaO, N
A method for producing wollastonite-based low-temperature fired glass ceramics containing a ₂ O and B ₂ O ₃ as main components. 4. The wollastonite low-temperature fired glass ceramic according to claim 3, wherein the fine powder of the compound containing CaO is a fine powder of calcium hydroxide and the fine powder of the compound containing B ₂ O ₃ is a fine powder of calcium metaborate. Manufacturing method. 5. The compounding ratio of soda-lime glass fine powder is 4
5. The wollastonite low-temperature fired glass ceramic according to claim 4, wherein the blending ratio of the calcium hydroxide fine powder is 3.7-17.9 wt%, and the blending ratio of the calcium metaborate fine powder is 14.2-45.2 wt%. Manufacturing method.