JP2003095734A - Composition for free-cutting glass ceramics, free-cutting glass ceramics, and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for free-cutting glass ceramics which can be sintered at a low temperature, and has excellent free-cutting properties, to provide free-cutting glass ceramics, and to provide a production method therefor. SOLUTION: The composition for glass ceramics contains, by weight, 40 to 75% borosilicate aluminum glass, and 25 to 60% filler powder. The borosilicate aluminum glass contains 20 to 70 wt.% of one or more metals selected from the group consisting of BaO, SrO and CaO, and the filler powder consists of synthetic mica.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a free-machining glass-ceramic which can be fired at a low temperature and can be easily ground, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, glass ceramics containing synthetic mica have been known as free-cutting glass ceramics. In the above glass ceramics, fluoromica is deposited in the glass ceramics. This reduces the grinding resistance of the glass ceramics during grinding and improves the free-cutting property. As a method for producing the glass ceramics, a method of melting a fluorine-containing mixture containing porcelain as a main raw material, treating a vitrified molded product in a fluorine atmosphere, and precipitating fluorine mica (Japanese Patent Publication No. 1-55205) Etc.

In the above-mentioned conventional method, the vitrified compact is heated at a high temperature of 1100 to 1360 ° C. in a fluorine atmosphere to precipitate the fluorine mica contained in the glass compact. This makes it possible to obtain glass ceramics.

On the other hand, in recent years, glass ceramics may be subjected to processing such as forming a conductor pattern for an electronic circuit or the like on the surface of the glass ceramics in order to meet various uses. Such processing may be performed after firing the above-mentioned glass molded body, but performing it before firing leads to cost reduction in order to simplify the working process.

[0005]

However, in the above-mentioned conventional method, it is necessary to heat at a high temperature of 1100 ° C. to 1360 ° C. in the fluorine atmosphere as described above in order to improve the free-cutting property. Therefore, when the above-mentioned conductor pattern or the like is formed on the surface of the glass ceramic, it is necessary to form the conductor pattern after heating at a high temperature. Further, the above-mentioned conventional method has a problem that it requires a special apparatus and process for creating a fluorine atmosphere, and needs to perform firing at an extremely high temperature, resulting in high cost.

In view of the above conventional problems, the present invention intends to provide a composition for free-cutting glass ceramics which can be fired at a low temperature and is excellent in free-cutting property, a free-cutting glass ceramics, and a method for producing the same. It is a thing.

[0007]

The first invention is 40 to 75% by weight of aluminum borosilicate glass and 25 to 60% by weight of filler powder.
A composition for glass ceramics, comprising: BaO, SrO and CaO
One or two or more selected from the group of 20 to 7
A free-machining composition for glass-ceramics, characterized in that the filler powder is contained in an amount of 0% by weight, and the filler powder is composed of synthetic mica (claim 1).

What is most noticeable in the present invention is that the aluminum borosilicate glass is BaO, SrO and Ca.
20 to 1 or 2 or more selected from the group of O
70% by weight is contained. Therefore, the composition for glass ceramics can be fired at a low temperature of 1000 ° C. or lower.

When the content of BaO, SrO and CaO contained in the above aluminum borosilicate glass is less than 20% by weight, the free-cutting glass ceramics after firing are difficult to be densified and water absorption occurs. Inconvenience may occur. On the other hand, if the above content exceeds 70% by weight, the glass tends to melt during firing, making it difficult to obtain a free-cutting glass ceramic having a desired shape.

The composition for free-cutting glass-ceramics of the present invention is 40-75% by weight of aluminum borosilicate glass.
And 25 to 60% by weight of filler powder composed of synthetic mica. Therefore, the free-cutting glass ceramics obtained by firing the above-mentioned free-cutting glass ceramics composition sufficiently contains synthetic mica. Therefore, it is possible to impart free-cutting property with excellent machinability.

When the content of aluminum borosilicate glass contained in the above composition for free-cutting glass ceramics is less than 40% by weight or when the content of filler exceeds 60% by weight, the above-mentioned free-cutting property is obtained. The fired body of glass ceramics is difficult to be densified, and there is a possibility that inconvenience such as water absorption may occur. On the other hand, when the content of borosilicate aluminum glass exceeds 75% by weight, or when the content of filler is less than 25%, it becomes difficult to grind the fired body, and the free-cutting property deteriorates and the firing Part of the body may melt and it may be difficult to obtain the desired shape of the free-cutting glass ceramics.

Therefore, according to the present invention, it is possible to provide a composition for free-cutting glass ceramics which can be fired at a low temperature and is excellent in free-cutting property.

The second invention is aluminum borosilicate glass 4
A glass ceramic obtained by molding and firing a composition having 0 to 75% by weight and 25 to 60% by weight of filler powder, wherein the borosilicate aluminum glass is BaO, Sr.
A free-machining glass-ceramic containing 20 to 70% by weight of one or more selected from the group consisting of O and CaO, and the filler powder consisting of synthetic mica (claim 2). .

The free-cutting glass ceramics of the present invention is obtained by molding and firing the composition for free-cutting glass ceramics according to the first invention. Therefore, the free-cutting glass ceramics has the same effect as the above-mentioned first invention. That is, according to the present invention, it is possible to provide a free-cutting glass ceramic which can be fired at a low temperature and is excellent in free-cutting property.

A third aspect of the invention is an aluminum borosilicate glass 4
0 to 75% by weight and 25 to 60% by weight of filler powder, and the borosilicate aluminum glass contains one or more selected from the group consisting of BaO, SrO and CaO.
0 to 70% by weight, and the filler powder is composed of synthetic mica; a step of preparing a composition; a step of molding the composition into a desired shape to obtain a molded body;
And a step of firing at 0 ° C. or lower.

What is most noticeable in the present invention is that it includes a step of firing the molded body at 1000 ° C. or lower. Since the above-mentioned composition for free-cutting glass-ceramics has the above-mentioned composition, it can be fired at a low temperature.
Firing can be performed at a low temperature of ℃ or less. Therefore, energy saving in the manufacturing process, that is, cost reduction can be achieved. In addition, the method for producing free-cutting glass ceramics of the present invention can produce the above-mentioned free-cutting glass ceramics without the need for a special method and apparatus of high temperature firing in a fluorine atmosphere as in the conventional method. Therefore, the free-cutting glass ceramics can be economically manufactured. The lower limit of the firing temperature is preferably 800 ° C.

The free-cutting glass-ceramic produced according to the present invention contains synthetic mica as described above. Therefore, the grinding resistance of the free-cutting glass ceramics during grinding can be reduced, and the free-cutting glass ceramics can be provided with excellent free-cutting properties.

Therefore, according to the present invention, it is possible to provide an economical manufacturing method of free-cutting glass ceramics which can be fired at a low temperature and is excellent in free-cutting property.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as the above synthetic mica, for example, fluorophlogopite, potassium tetrasilicon mica and the like can be used. Further, as fillers other than synthetic mica, Al ₂ O ₃ , SiO ₂ , ZrO ₂ , 3Al ₂ O ₃ .2S
It may contain one or more of iO ₂ , MgO, ZrSiO ₄ , and 2MgO.SiO ₂ .

The above aluminum borosilicate glass is
Note 1 selected from the group of BaO, SrO and CaO
, Including two or more kinds, SiO₂, B₂O₃, Al₂O
₃Contains. Also, K₂O, Na₂O, Li₂O, M
gO, ZnO, TiO₂, P ₂O_Five, Bi₂O₃More than one kind
May include the above.

Next, in the second invention (claim 2), it is preferable that a conductor pattern is formed on the surface of the free-cutting glass ceramics (claim 3). In this case, the free-cutting glass ceramics can be used for an electronic circuit board or the like.

In the third invention (claim 4), it is preferable that the method further comprises a step of printing a conductor pattern on the molded body before the step of firing the molded body (claim 5). In this case, the conductor pattern and the molded body can be simultaneously fired. Since the molded body has the composition described above, it can be fired at a low temperature of 1000 ° C. or lower. Therefore, the sintering and fixing of the conductor pattern formed on the surface of the molded body and the firing of the molded body can be performed at the same time, and the conductor pattern is not deformed or destroyed by this.

In particular, when Ag, Cu, Au or the like having a low conductor resistance is used as the conductor pattern, since the melting point of these is around 1000 ° C., it is significant that the above firing can be performed at 1000 ° C. or less. It is an advantage. That is, the simultaneous firing of the conductor pattern and the molded body is a great technical and economical effect.

[0024]

(Example 1) In this example, an example of producing the above-mentioned composition for free-machining glass-ceramics, molding and firing the composition to produce free-cutting glass-ceramics is shown. In this example, the composition ratio of the above-mentioned free-cutting glass-ceramics and the firing temperature were changed.
The water absorption rate and grinding resistance value were measured. This example will be described in detail below.

In this example, first, ten kinds of powders having compositions (1) to (10) shown in Table 1 were prepared as powders of aluminum borosilicate glass.

[0026]

[Table 1]

Next, the above-mentioned ten kinds of powders (1) to (10) and synthetic mica as a filler were blended to prepare a composition for free-cutting glass ceramics. The compounding ratio of the aluminum borosilicate glass powders (1) to (10) and the synthetic mica was changed as shown in Table 2. The blending ratios shown in Table 2 are shown in Table 1.
The ratio of the weight% of the powder of aluminum borosilicate glass (1) to (10) and the weight% of the synthetic mica are shown.

These free-cutting glass-ceramic compositions were wet-mixed and dried, then an organic binder was added, and the mixture was molded by the doctor blade method. Then, the obtained molded body was fired in an oxidizing atmosphere while changing the firing temperature up to 1000 ° C. to obtain a free-cutting glass ceramic. Among various free-cutting glass ceramics shown in Table 2, Samples E1 to E22 are products of the present invention, Samples C1 to C9 are comparative products, and Ca1 is a conventional example described later.

The water absorption of each of the obtained samples was measured according to JISC214.
The measurement was carried out according to 1, and the firing temperature of each sample was also measured. The firing temperature was defined as the minimum temperature at which the water absorption rate was 0.1% or less. That is, when firing is performed at a temperature lower than each firing temperature in Table 2, the water absorption of the free-cutting glass ceramics is 0.1%.
And the so-called raw-burning state is exceeded. The results of these measurements are shown in Table 2.

Further, the free-cutting properties of the above samples were evaluated.
The evaluation of the free-cutting property is as follows: the rotation speed of the grindstone is 10 krpm, the cutting depth is 0.5 mm, and the feed speed of the grindstone is 100 mm / mi.
The sample was ground under the condition of n, and the grinding resistance value at this time was measured. The measurement results are shown in Table 2.

(Conventional Example) In this example, a glass ceramics is produced by the method (Japanese Patent Publication No. 1-55205) shown in the above-mentioned prior art, and the same measurement as in Example 1 is performed.

First, raw materials were mixed to prepare a glass composition, which was vitrified at 1400 ° C. to obtain a glass molded body. Next, as shown in FIG. 1, a ceramic container 1 containing a fluorine compound 2 in the ceramic container 1 was prepared.
The glass molded body 3 is placed in the ceramic container 1, and the ceramic container lid 4 is heated. By this,
Fluorine vaporizes from fluorine compound 2 and ceramic container 1
The inside is kept in a fluorine atmosphere.

In this state, the above glass molded body was heated at 1200 ° C.
The glass ceramics (Sample Ca1) was manufactured by heating. The chemical composition of the glass-ceramic composition is described in Japanese Patent Publication No. 1-55205.

[0034]

[Table 2]

As known from Table 2, samples E1 to E2
No. 2 (invention product) has a baking temperature of 1000 ° C or less and a water absorption rate of 0.1% or less, and a low temperature (1000 ° C or less)
It is possible to sinter sufficiently. As for the grinding resistance value, the samples E1 to E22 show a low value of 180 W or less, and the samples E1 to E22 have excellent free-cutting property.

Further, the manufacturing method of this embodiment does not require a special device in any of the steps of adjusting the composition, obtaining the molded body, and firing. In addition, in the firing process, since firing is performed at a low temperature of 1000 ° C. or less, energy saving can be achieved.

On the other hand, samples C1 to C6 and sample C9
Has a water absorption rate of more than 0.1% even if it is fired at 1000 ° C., and is in a so-called green state. That is, these samples are not suitable for low temperature firing. Further, in Samples C7 and C8, the water absorption rate is less than 0.1% at 1000 ° C. or less, but the grinding resistance value exceeds 180 W, so that the grinding process is difficult.

Further, the sample Ca1 which is a conventional example shows a water absorption rate of 0.1% or less, but it is necessary to heat at a high temperature of 1200 ° C. after vitrifying at 1400 ° C. Can't do. Further, the grinding resistance value exceeds 180 W, and it does not have sufficient free-cutting property as compared with the product of the present invention.

Further, in order to manufacture the sample Ca1, a special device is required as shown in FIG. 1 described above, but the manufacturing method of the products of the present invention (sample E1 to sample E22) is such a special device. No equipment required. Therefore, the manufacturing cost can be reduced.

The samples E1 to E22 and the sample Ca1 are
Both contain fluoromica. However, while the grinding resistance values of Samples E1 to E22 are 180 or less,
The grinding resistance value of the sample Ca1 exceeds 180. Thus, it can be seen that the products of the present invention (Samples E1 to E22) have better free-cutting properties than the conventional products (Sample Ca1).

As described above, according to this example, it is possible to provide a composition for free-cutting glass ceramics which can be fired at a low temperature and is excellent in free-cutting property, a free-cutting glass ceramics, and a method for producing the same. .

(Example 2) In this example, a free-cutting glass ceramic having a conductor pattern is produced.

First, a free-cutting glass-ceramic composition having the same composition as that of Samples E1 to E22 of Example 1 was prepared. The composition for free-cutting glass-ceramics was used in Example 1.
Molding was performed in the same manner as above to produce a molded body of free-cutting glass ceramics as an electronic circuit board. Next, a conductor paste is applied to the above molded body by a screen printing method,
A conductor pattern was formed. As the conductor paste, Ag
A powder obtained by adding an acrylic resin and glass powder as an organic binder was used.

Next, the molded body printed with the conductor paste was fired to prepare free-cutting glass ceramics (sample E1 to sample E22) having a conductor pattern. This free-cutting glass-ceramic is used as an electronic circuit board. As shown in FIG. 2, the conductor pattern 6 is formed on the surface of the free-cutting glass ceramic 5.

Free-cutting glass-ceramics (conductor samples E1 to E2) having a conductor pattern produced as described above.
In 2), no abnormality was observed after firing, and the conductor pattern maintained the shape formed in the molded body. From this, it is understood that Samples E1 to E22 (invention products) can be fired simultaneously with the conductor pattern. It is also possible to produce a multilayer substrate from the above-mentioned product of the present invention by a printing lamination method, a thick film lamination method, or the like.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method for firing a glass molded body according to a conventional example.

FIG. 2 is an explanatory diagram of an electronic circuit board according to a second embodiment.

[Explanation of symbols]

1. ． ． Ceramic container, 2. ． ． Fluorine compound, 3. ． ． Glass molding, 4. ． ． Ceramic container, 5. ． ． Free-cutting glass ceramics, 6. ． ． Conductor pattern,

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G030 AA02 AA03 AA04 AA07 AA08                       AA09 AA10 AA16 AA17 AA32                       AA35 AA36 AA37 AA41 AA43                       BA12 BA18 CA08 GA04 GA14                       GA20 GA25 GA27 HA04 HA07                       HA09 HA14

Claims (5)

[Claims] 1. A composition for glass ceramics comprising 40 to 75% by weight of aluminum borosilicate glass and 25 to 60% by weight of filler powder, wherein the aluminum borosilicate glass is selected from the group consisting of BaO, SrO and CaO. The composition for free-cutting glass-ceramics, characterized in that it contains 20 to 70% by weight of one or more of the following, and the filler powder is composed of synthetic mica. 2. A glass ceramic obtained by molding and firing a composition comprising 40 to 75% by weight of aluminum borosilicate glass and 25 to 60% by weight of filler powder, wherein the aluminum borosilicate glass is BaO or SrO. And CaO
One or two or more selected from the group of 20 to 7
A free-cutting glass-ceramic containing 0% by weight and the filler powder made of synthetic mica. 3. The free-cutting glass ceramic according to claim 2, wherein a conductor pattern is formed on the surface of the free-cutting glass ceramic. 4. A borosilicate aluminum glass of 40 to 75% by weight and a filler powder of 25 to 60% by weight, wherein the borosilicate aluminum glass comprises one or more selected from the group consisting of BaO, SrO and CaO. 20 to 70% by weight, and the filler powder is composed of synthetic mica,
A free-machining glass-ceramic, comprising: a step of preparing a composition; a step of molding the composition into a desired shape to obtain a molded body; and a step of firing the molded body at 1000 ° C. or lower. Production method. 5. The method for producing a free-cutting glass ceramic according to claim 4, further comprising a step of printing a conductor pattern on the molded body before the step of firing the molded body.