JP2002327201A - Golden powder for dipping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide golden powder for dipping, which has preferable gloss, sinks slowly in paint, and uniformly adheres to an article to be coated. SOLUTION: The gold powder for dipping is flaky brass powder characterized by having an average particle size of 40-60 μm, an apparent density of 0.5-0.7 g/cm<3> , and a specific surface area of 7000 cm<2> /g or more by the BET method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dipping method for immersing an object to be coated in a gold paint to obtain a golden decorative product. The dipping method has good adhesion of gold powder to the object to be coated and exhibits excellent golden luster. It is related to gold powder.

[0002]

2. Description of the Related Art At Christmas and the like, pine cones, processed vines, leaves, and other beautifully decorated decorative items are painted in gold. These gold decorative articles are manufactured by a dipping method in which an object to be coated is immersed in a gold paint mixed with gold powder, then taken out and dried. Coatings with uneven surfaces, such as pine cones and processed vines, have poor workability by spray coating or brush coating, making it difficult to apply them evenly to the inside, and are often manufactured by a dipping method. In the dipping method, the gold powder tends to settle to the bottom of the container because the liquid is not usually stirred while the object to be coated is immersed. The use of gold powder having a small particle size eliminates the problem of sedimentation, but deteriorates gloss.

[0003] When a painted object is taken out of the gold paint, a phenomenon occurs in which the gold powder does not remain on the surface of the article to be coated and only the gold powder flows down. As a result, there is a portion to which the gold powder is not attached, the base is visible, or the color becomes uneven, and a beautiful gold ornament is not obtained.

[0004]

SUMMARY OF THE INVENTION The present inventors have obtained a glittering golden luster, a low sedimentation speed in paint,
It was completed as a result of research on gold powder most suitable for the dipping method in which the gold powder adheres uniformly to the object to be coated.

[0005]

That is, the present invention relates to a flake brass powder having an average particle size of 40 to 60 μm, having a BET specific surface area of 7000 cm 2 / g or more and an apparent density of 0.5 to 0.5 μm.
It is a gold powder for dipping, which is 0.7 g / cm3.

[0006] Flake brass powder is a metal powder pigment produced by a mechanical pulverization method, and is a flake copper-zinc alloy powder coated with a fatty acid, and is called gold powder or bronze powder. The reason for limiting the average particle size of the gold powder to 40 to 60 μm is that
If it is finer than this, excellent gloss cannot be obtained because the surface of the coated product is uneven. On the other hand, if the average particle size is larger than 60 μm, the wettability is poor and a uniform golden coating film cannot be obtained. The average particle size of the gold powder is a measured value of the average particle size by a laser diffraction measuring apparatus.

The BET specific surface area of the gold powder is 7000 cm.
It is necessary to be 2 / g or more. If it is less than that, the sedimentation is fast, the base cannot be hidden, and a beautiful golden ornament cannot be obtained. The BET specific surface area value makes the particle size of gold powder fine,
For example, when the thickness is 30 μm or less, there is a gold powder for coating having a specific surface area of 7000 cm 2 / g or more, but the gloss is poor at this particle size. It is necessary that the average particle size is 40 to 60 μm and the BET specific surface area value is 7000 cm 2 / g or more. The BET specific surface area value is a value measured by a BET specific surface area measuring device that adsorbs an inert gas.

The apparent density of the gold powder is 0.5 to 0.7 g / cm.
It is important that it is 3. 0.5g / cm3 apparent density
When the bulky gold powder is less than the above, the fluidity of the paint becomes extremely poor, and it cannot be uniformly applied to the surface of the object to be coated. 0.7 apparent density
In the case of a low bulk gold powder of greater than g / cm 3, only the gold powder flows down from the coating surface of the coating object when the object to be coated is taken out of the coating material, and the gold powder does not adhere. Conventional gold powder is often spray-painted or brushed, so the average particle size is 3
It was 5 μm or less, and the apparent density was 1.1 to 1.5 g / cm 3 in order not to deteriorate the fluidity of the paint.

However, according to the study of the present inventors, gold powder as in the prior art is not good for the dipping method, and gold powder having the powder characteristics of the present invention is optimal. The method for obtaining the gold powder of the present invention is to put the brass powder together with steel balls in an agitator mill, a ball mill, or the like, add a small amount of fats and oils, and spread the flakes into a flaky shape. Gold powder has already been produced in large quantities, and gold powder for dipping can be produced by adjusting the production method only to the powder characteristics of the present invention using existing production facilities.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The reason why the gold powder of the present invention exhibits excellent performance for dipping is that the average particle diameter is larger than that of ordinary paint or coating gold powder, and the specific surface area is larger. That is, the thickness of the particles is gold powder thinner than the conventional powder. A flake having a small thickness and a large particle diameter has a low sedimentation in the paint, and has excellent redispersibility even if it sediments, and a glittering luster can be obtained even if the surface is uneven.

This is a very bulky gold powder having a small apparent density value. The coating fluidity of the paint mixed with the bulky flakes becomes poor. That is, the poor fluidity of the coating film when the object to be coated is immersed and pulled up prevents the gold powder from flowing from the coating film and falling. In our study, even when the average particle size is the same as 40 μm, the paint viscosity using gold powder having an apparent density of 1.2 g / cm 3 is 10 μm.
25mPa · s at 0rpm, but apparent density 0.6g / c
Paint viscosity of 75mPa ·
s and viscosity are tripled. As a result, the gold powder will adhere evenly to vegetable oil layers such as pine cones, which are difficult to adhere to.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described in detail as follows. It should be noted that this does not limit the production method and use of the invention.

(Example 1) Brass composed of 90% Cu and 10% Zn was melt-sprayed to obtain a granular metal powder having an average particle diameter of 20 µm. Next, the metal powder was crushed into a flake by a medium stirring mill using a ４ inch steel ball as a crushing medium. Grinding condition is 1000k steel ball of grinding media
g, 100 kg of metal powder and 50 g of a grinding aid, stearic acid, were added per hour, and the mixture was pulverized in the air at 50 rpm while keeping the amount of metal powder in the pulverizer constant. The coarse powder and the fine powder were classified by a cyclone to obtain 25 kg of flaky brass powder per hour. 0.2% stearic acid was added to the flaky brass powder thus obtained, and glazing was performed using a brush-type polishing machine. As a result of examining the properties of the powder obtained by removing the foreign matter with a 200 μm sieve, the average particle size was 40 μm, the BET specific surface area was 7000 cm 2 / g, and the apparent density was 0.7 g / cm 3.
Gold powder for dipping was produced. 25 parts by weight of the thus-prepared gold powder for dipping is coated with an acrylic paint 75.
The mixture was mixed in parts by weight and stirred with a mixer to produce a golden paint. The pine cone was immersed in the prepared golden paint, taken out with a net, and air-dried as it was. As a result, it was possible to produce a glittering and glossy uniform gold ornament. The settling of the gold powder was also slow, and no stirring of the liquid was required during the operation.

(Example 2) Brass composed of 90% Cu and 10% Zn was melt-sprayed to obtain a granular metal powder having an average particle diameter of 20 µm. Next, the metal powder was pulverized into a flake by a medium stirring mill using 1/2 inch steel balls as a pulverizing medium. Grinding conditions are steel balls 1000k of grinding media
g, 100 kg of metal powder, and 100 g of stearic acid as a grinding aid per hour were added, and pulverization was performed in air while keeping the amount of metal powder in the pulverizer constant at 100 rpm. The coarse powder and the fine powder were classified by a cyclone to obtain 100 kg of flaky brass powder per hour. Using the flake powder thus obtained as a starting material, 1000 kg of 1/8 inch steel balls, 100 kg of flake powder, and 50 g of stearic acid as a grinding aid per hour were added using a medium stirring mill, and the rotation speed was increased to 70 rpm.
The crushing was performed again in the air while keeping the amount of metal powder in the crusher constant at pm. The coarse powder and the fine powder were classified by a cyclone to obtain 100 kg of flaky brass powder per hour. 0.2% of stearic acid was added to the flaky brass powder thus obtained, and glazing was performed using a brush-type polishing machine. As a result of examining the characteristics of the powder obtained by removing the foreign substances with a 200 μm sieve, the average particle diameter was 60 μm, and the specific surface area value of the BET method was 10,000 cm 2 /
g, a gold powder for dipping having an apparent density of 0.5 g / cm3 was produced. Gold powder 2 for dipping produced in this way
5 parts by weight was mixed with 75 parts by weight of an acrylic paint and stirred with a mixer to prepare a golden paint. The pine cone was immersed in the prepared golden paint, taken out with a net, and air-dried as it was. As a result, it was possible to produce a glittering and glossy uniform gold ornament. The settling of the gold powder was also slow, and no stirring of the liquid was required during the operation.

Example 3 Brass consisting of 75% Cu and 25% Zn was melt-sprayed to obtain a granular metal powder having an average particle diameter of 20 μm. Next, the metal powder was pulverized into a flake by a medium stirring mill using 1/2 inch steel balls as a pulverizing medium. Grinding conditions are steel balls 1000k of grinding media
g, 100 kg of metal powder and 150 g of a grinding aid, stearic acid, were added per hour, and the mixture was pulverized in the air at 100 rpm while keeping the amount of metal powder in the pulverizer constant. The coarse powder and the fine powder were classified by a cyclone to obtain 100 kg of flaky brass powder per hour. Using the flake powder thus obtained as a starting material, 1000 kg of 1/8 inch steel balls, 100 kg flake powder and 75 g of stearic acid as a grinding aid are added per hour using a medium stirring mill, and the number of rotations is increased to 70 rpm.
The crushing was performed again in the air while keeping the amount of metal powder in the crusher constant at pm. The coarse powder and the fine powder were classified by a cyclone to obtain 100 kg of flaky brass powder per hour. 0.25% of stearic acid was added to the flaky brass powder thus obtained, and glazing was performed using a brush-type polishing machine. 200 μm
As a result of examining the characteristics of the powder obtained by removing the foreign matter with a sieve, the average particle size was 48 μm, and the specific surface area value by the BET method was 9800 cm 2 /
g, a gold powder for dipping having an apparent density of 0.6 g / cm3 was produced. Gold powder 2 for dipping produced in this way
5 parts by weight was mixed with 75 parts by weight of an acrylic paint and stirred with a mixer to prepare a golden paint. The pine cone was immersed in the produced golden paint, taken out with a net, and air-dried as it was. As a result, it was possible to produce a glittering and glossy uniform gold ornament. The settling of the gold powder was also slow, and no stirring of the liquid was required during the operation.

(Example 4) Brass consisting of 75% Cu and 25% Zn was melt-sprayed to obtain a granular metal powder having an average particle diameter of 20 µm. Next, the metal powder was pulverized into a flake by a medium stirring mill using 1/2 inch steel balls as a pulverizing medium. Grinding conditions are steel balls 1000k of grinding media
g, 100 kg of metal powder, and 150 g of a grinding aid, stearic acid, were added per hour, and pulverization was performed in the air while keeping the amount of metal powder in the pulverizer constant at 100 rpm. The coarse powder and the fine powder were classified by a cyclone to obtain 100 kg of flaky brass powder per hour. Using the flake powder thus obtained as a starting material, a ball mill is used to add 1000 kg of 1/8 inch steel balls, 100 kg of flake powder, and 150 g of stearic acid as a grinding aid.
Crushed for hours. 0.25% of stearic acid was added to the flaky brass powder thus obtained, and glazing was performed using a brush-type polishing machine. As a result of examining the characteristics of the powder obtained by removing foreign substances with a 200 μm sieve, the average particle diameter was 51 μm, the specific surface area by the BET method was 11,000 cm 2 / g, and the apparent density was 0.6 g / g.
A cm3 gold powder for dipping could be produced. 25 parts by weight of the thus-prepared gold powder for dipping was mixed with 75 parts by weight of an acrylic paint and stirred with a mixer to prepare a golden paint. The pine cone was immersed in the produced golden paint, taken out with a net, and air-dried as it was. As a result, it was possible to produce a glittering and glossy uniform gold ornament. The settling of the gold powder was also slow, and no stirring of the liquid was required during the operation.

[0017]

Comparative Example (Comparative Example 1) Commercially available, average particle size 40
Using gold powder for paint having a specific surface area of 5,500 cm 2 / g and an apparent density of 1.3 g / cm 3, 25 parts by weight of gold powder was mixed with 75 parts by weight of an acrylic paint in the same manner as in Example 1, and a mixer was used. The mixture was stirred to produce a golden paint. The pine cone was immersed in the produced golden paint, taken out with a net, and air-dried as it was. As a result, many gold powders flowed down by the time of drying of the coating film, and uniform gold ornaments could not be manufactured.
The settling of the gold powder was fast, and the solution had to be stirred many times during the operation.

[0018]

As described above, ornaments painted in gold as Christmas ornaments often decorate home windows and trees. However, conventional gold powder has not been developed for use in the dipping of processed products such as plants, so there are problems such as the gold powder settling in the paint, the gold powder does not adhere well to the object to be coated, and the gloss is poor. Was something. However, the use of the gold powder for dipping of the present invention provides a brilliant luster, the sedimentation is slow, and there is no need to stir during the dipping work. It can be manufactured.

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Claims (1)

[Claims] 1. A flaky brass powder having an average particle size of 40 to 60 μm, having a BET specific surface area of 7000 cm 2 / g or more and an apparent density of 0.5 to 0.7 g / cm 3. And gold powder for dipping.