JP2000246127A - Method for grinding metallic hydroxide and production of metallic hydroxide for resin filler by using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the incorporation of coarse particles into a product by continuously charging a metallic hydroxide and air of a specific ratio into a dry ball mill to grind the metallic hydroxide such as aluminum hydroxide used as a filler for resins or rubber. SOLUTION: In the case of grinding the metallic hydroxide, 100 pts.vol. metallic hydroxide and 100-300 pts.vol. air are continuously charged into the dry ball mill and treated. When the quantity of air is smaller than 100 pts.vol., there is no effect to suppress re-aggregation, and the coarse particles are incorporated into the resultant product. When the quantity of air is larger than 3000 pts.vol., a part of the metallic hydroxide is discharged from the ball mill without being sufficiently ground. As the metallic hydroxide, aluminum hydroxide, magnesium hydroxide or the like is exemplified. The metallic hydroxide preferably has usually about 20 μm to about 120 μm average particle diameter and <=1.5 m2/g BET specific surface area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for pulverizing a metal hydroxide and a method for producing a metal hydroxide for filling a resin using the method. More specifically, the present invention relates to a method of pulverizing a metal hydroxide for obtaining a metal hydroxide with less coarse particles using a dry ball mill and a method of producing a metal hydroxide for filling a resin such as artificial marble using the method.

[0002]

2. Description of the Related Art Metal hydroxides such as aluminum hydroxide and magnesium hydroxide are widely used as fillers for resins and rubbers. The required physical properties such as the average particle size of these metal hydroxides vary depending on applications such as wallpaper, carpet, paint, electric wire resin, foamed resin, artificial marble, and rubber. There is a pulverization method as a method for obtaining a metal hydroxide having desired required physical properties.

Various pulverizers for pulverizing metal hydroxide have been developed and are commercially available. Above all, dry ball mills are widely used.

However, conventionally, when a metal hydroxide is pulverized by a pulverization method using a dry ball mill, reaggregation or the like occurs, and there is a problem that coarse particles are mixed into the obtained metal hydroxide.

[0005]

In view of such circumstances,
The present inventors have conducted intensive studies on a pulverizing method using a ball mill and a method for producing a metal hydroxide for resin filling that can suppress the incorporation of coarse particles into the product, and as a result, introduce a specific amount of air into the ball mill. As a result, the present inventors have found that all such problems can be solved, and have completed the present invention.

[0006]

That is, the present invention provides a method for pulverizing metal hydroxide by continuously introducing 100 parts by volume of metal hydroxide and 100 to 3000 parts by volume of air into a dry ball mill. To be.

Further, the present invention provides a method for producing a metal hydroxide for resin filling using a pulverizing method in which 100 parts by volume of a metal hydroxide and 100 to 3000 parts by volume of air are continuously introduced into a dry ball mill. To be.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The invention is based on 100 parts by volume of metal hydroxide and 100 parts by volume of air.
3,000 volume parts is continuously introduced into a dry ball mill. When the amount of air is less than 100 parts by volume, there is no effect of suppressing reagglomeration or the like, and coarse particles are mixed in the obtained product. When the amount of air is more than 3000 parts by volume, some metal hydroxides are discharged from the ball mill without being sufficiently pulverized, and coarse particles are mixed in the product. Also, it may be difficult to collect the product.

The metal hydroxide used in the present invention is, for example,
Aluminum hydroxide [shown by a general formula: Al ₂ O ₃ · mH ₂ O (m = 1 to 3). Specific gravity 2.42 to 3.06],
Magnesium hydroxide [Mg (OH) ₂ , specific gravity 2.3
6], calcium hydroxide [Ca (OH) ₂ , specific gravity 2.2
4], preferably Al ₂ O ₃ .3H ₂ O (specific gravity 2.42)
It is. The metal hydroxide usually has an average particle size of about 20 μm to about 120 μm and a BET specific surface area of 1.
It is preferably at most 5 m ² / g.

According to the classification in the Chemical Engineering Handbook, Revised 5th Edition, pages 829 to 834 (Maruzen Co., Ltd., issued March 18, 1988), a dry ball mill used in the present invention is a continuous ball mill. Well, for example rolling ball mill,
Vibration ball mills, planetary ball mills and the like, preferably vibration ball mills are exemplified. In addition, in addition to the powder supply device that introduces metal hydroxide into the mill,
In order to introduce air into the mill, an air supply device such as an air compressor or an air cylinder is connected via piping. The method of introducing air into the mill is, for example, by introducing air into the mill through a pipe from an air supply device so as to be in a cocurrent or countercurrent direction with the metal hydroxide, preferably in a cocurrent direction. Good.

The pulverization conditions are different depending on the kind of the metal hydroxide, the desired average particle diameter, the kind of the ball mill and the like, and are not unique, but usually, the pulverization temperature is about 40 ° C. to about 120 ° C.
C., preferably about 60 ° C. to 100 ° C., the grinding time (= average residence time of the metal hydroxide in the ball mill) is about 5 minutes to 200 minutes, and the grinding medium has a diameter of about 1 mm to 80 minutes.
mm ball, preferably 5 mm to 30 mm ball, wherein the apparent loading of the grinding media is about 30% to about 95%, preferably about 50% to 90%, based on the ball mill volume. The pulverization time and the like can be easily determined by conducting a preliminary pulverization experiment according to the desired average particle size of the metal hydroxide and the like.

In carrying out the metal hydroxide pulverizing method of the present invention, for example, a metal hydroxide such as aluminum hydroxide and air from an air supply device are continuously introduced into a continuous vibration ball mill, and the metal hydroxide is pulverized. Is retained in the ball mill and pulverized, and then the pulverized metal hydroxide may be recovered.When the method for producing a metal hydroxide for resin filling of the present invention is performed, for example, a metal such as aluminum hydroxide may be used. The hydroxide and the air from the air supply device are continuously introduced into the continuous vibration ball mill, and the metal hydroxide is allowed to flow for a predetermined time so that the average particle diameter of the obtained metal hydroxide for resin filling has a desired value. After being retained in the ball mill and pulverized, the pulverized metal hydroxide may be recovered.

[0013] In addition, as long as the effects of the present invention are not lost, a surface treating agent is simultaneously introduced into the ball mill,
It is also possible to surface-treat the metal hydroxide. Examples of the surface treatment agent include methacrylic, acrylic, vinyl, epoxy, silane and amino silane coupling agents. The amount of the surface treatment agent is usually about 0.1 part by weight to about 3 parts by weight based on 100 parts by weight of the metal hydroxide.

The metal hydroxide for resin filling obtained in the method for producing a metal hydroxide for resin filling of the present invention is usually
Average particle size is about 1 μm to about 40 μm, preferably about 5 μm
m to 30 μm. When the average particle diameter is out of the above range, the filling property of the resin-filling metal hydroxide into the resin tends to decrease. Further, the metal hydroxide for resin filling obtained in the present invention usually has an amount of +45 μm of about 5% or less and an amount of +106 μm of about 0.2% by weight or less.

The resin to be compounded with the metal hydroxide for filling the resin is not particularly limited. In the case of artificial marble or FRP using aluminum hydroxide, for example, unsaturated polyester resin, vinyl ester resin, methyl methacrylate Resins, epoxy resins, and the like. The filling amount of the aluminum hydroxide of the present invention in the resin is, for example, about 50 parts by weight to about 400 parts by weight, preferably about 150 parts by weight to about 300 parts by weight, per 100 parts by weight of the resin.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In this example, the average particle size and the BET specific surface area were measured by the following methods. Average particle diameter (μm): Measured with a laser scattering particle size distribution analyzer (Microtrac HRA manufactured by LEED & NORTHRUUP). +45 μm amount (% by weight): measured by a wet sieving method. +106 μm amount (% by weight): measured by a wet sieving method. BET specific surface area (m ² / g): measured by a nitrogen adsorption method.

Example 1 BE powder having an average particle diameter of 50 μm was measured using a powder feeder.
T specific surface area is 0.2m ^Two/ G and specific gravity of 2.42
100 parts by volume of aluminum hydroxide
Air is connected to the air mill via piping.
530 parts by volume in the direction of cocurrent with the aluminum hydroxide
A continuous vibration ball mill (ball diameter: 8m)
m, ball filling rate: 90%, average residence time: 18 minutes)
Continuously introduced and pulverized, aluminum hydroxide for resin filling
Obtained. The physical properties of the obtained aluminum hydroxide for resin filling
It is shown in Table 1. The amount of +106 μm is the amount of ground metal hydroxide.
Are re-aggregated, and the amount of +45 μm
Is discharged from the mill without sufficient grinding.
You.

Example 2 In Example 1, the amount of air was increased from 530 parts by volume to 1230 parts.
The procedure was performed in the same manner as in Example 1 except that the capacitance part was changed. Table 1 shows the physical properties of the obtained aluminum hydroxide for resin filling.

Comparative Example 1 Except that no air was introduced in Example 1,
Performed in the same manner as in Example 1. Table 1 shows the physical properties of the obtained aluminum hydroxide for resin filling.

Comparative Example 2 In Example 1, the amount of air was increased from 530 parts by volume to 3500 parts.
The procedure was performed in the same manner as in Example 1 except that the capacitance part was changed. Table 1 shows the physical properties of the obtained aluminum hydroxide for resin filling.

[0021]

[Table 1]

[0022]

As described in detail above, the present invention provides a method for pulverizing a metal hydroxide and a resin filling method capable of suppressing the incorporation of coarse particles into a product by a simple method such as introducing air into a ball mill. The present invention provides a method for producing a metal hydroxide, and its industrial utility value is great.

Claims (6)

[Claims] 1. 100 parts by volume of metal hydroxide and 100 parts of air
A method for pulverizing a metal hydroxide, comprising continuously introducing up to 3000 parts by volume into a dry ball mill. 2. The method for crushing metal hydroxide according to claim 1, wherein said air is introduced into the mill from an air supply device via a pipe. 3. The method according to claim 1, wherein the metal hydroxide is aluminum hydroxide. 4. 100 parts by volume of metal hydroxide and 100 parts of air
A method for producing a metal hydroxide for resin filling, using a pulverization method in which 3,000 volume parts are continuously introduced into a dry ball mill. 5. The method for producing a metal hydroxide for resin filling according to claim 4, wherein the air is introduced into the mill from an air supply device via a pipe. 6. The method for producing a metal hydroxide for resin filling according to claim 4, wherein the metal hydroxide is aluminum hydroxide.