JP2001192869A - Rust preventive pigment for galvanized steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conqure the point at issue in the conversion of a rust preventive pigment for a galvanized steel sheet composed of an amorphous magnesium silicate compound in which the atomic ratio of Mg/Si is 0.025 to 1.0 into a coating material. SOLUTION: A dense inorganic carrier is coated with the above amorphous magnesium silicate. In this way, oil absorption reduces, and its dispersibility improves. Moreover, the moisture resistance of the coating material improves, so that its rust preventability also increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-polluting rust preventive pigment used for a primer of a galvanized steel sheet, in particular, a galvanized steel sheet used as a material of a precoated metal (PCM).

[0002] PCM using a galvanized steel sheet as a raw material is produced by subjecting a plating layer to a chemical conversion treatment and then coating a primer and then a top coat layer. Since the PCM is subjected to machining such as cutting and bending after coating, the steel sheet and the galvanized layer are exposed on the cut surface. Therefore, white rust having no sacrificial electrode effect is generated on the galvanized layer on the cut surface, and finally rust is generated therefrom to the steel plate portion. Therefore, the rust-preventive pigment used for the galvanized steel sheet is required to have a rust-preventive performance against the galvanized layer firstly.

For this purpose, strontium chromate-based rust-preventive pigments have been widely used so far. However, since this pigment contains harmful hexavalent chromium, a non-polluting rust-preventive rust-proof pigment has been developed as an alternative. Was desired.

In order to satisfy this demand, the present inventors disclosed in Japanese Patent Application No. 11-78803 that the Mg / Si atomic ratio was 0.1.
A rust preventive pigment for a galvanized steel sheet comprising an amorphous hydrated magnesium silicate compound having a ratio of 025 to 1.0 is disclosed.

[0005] However, although the rust-preventive performance of the amorphous hydrous magnesium silicate compound itself is comparable to that of strontium chromate, it has been found that there are some problems in the preparation of paint and that further improvement is required in practical use.

One of them is a high oil absorption. For example, the oil absorption of a titanium oxide pigment is usually on the order of 20 mL / 100 g, but for this pigment it is usually on the order of 140 mL / 100 g. Therefore, the amount of the diluent organic solvent (thinner) required to adjust the viscosity of the paint to a level at which the paint can be applied must be increased, which makes it difficult to make the paint high solid.

Another problem is that the average particle size of the pigment is relatively large due to poor pulverizability, so that a long time is required for the step of dispersing in the paint, and the resulting paint has insufficient gloss.

It is an object of the present invention to provide a rust preventive pigment which can maintain the rust preventive performance of the above-mentioned amorphous magnesium silicate compound, and can overcome the problem in forming a paint.

[0009]

An object of the present invention is to provide a method for coating a zinc-coated steel sheet having a dense inorganic carrier coated with an amorphous hydrous magnesium silicate compound having an Mg / Si atomic ratio of 0.025 to 1.0. The problem is solved by providing an antirust pigment.

[0010] While this pigment retains rust-preventive performance by the amorphous hydrous magnesium silicate compound of the coating layer,
Since the ratio of the carrier in the core part contributing to the oil absorption is negligibly small, the oil absorption of the entire pigment is reduced. Further, the dispersibility in the paint is increased, and thus the gloss of the coating film is improved. Further unexpectedly, it has been found that the pigments of the present invention improve the moisture and rust resistance of the coating compared to pigments without a carrier core.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pigment of the present invention can be produced by carrying out a synthetic reaction of amorphous hydrous magnesium silicate in an aqueous solution in the presence of carrier particles. As described in Japanese Patent Application No. 11-78803 of the present applicant, the alkali metal silicate and the aqueous magnesium salt are mixed at an Mg / Si atomic ratio of 0.025 to 1.0,
Preferably, the reaction is carried out in an aqueous solution at a ratio of 0.025 to 0.8. If carrier particles are present in the reaction solution, the generated amorphous hydrous magnesium silicate coats the carrier particles. After the completion of the reaction, this is separated from the reaction solution by filtration, washed with water, dried and pulverized to obtain the pigment of the present invention.

Substances that can be used as carriers are inorganic compounds that are insoluble in water and have a dense structure. Generally, they are crystalline. Further, since the amorphous hydrous magnesium silicate itself is white, the carrier is also preferably white or gray or yellowish white. Non-limiting examples of such materials are titanium oxide, talc, aluminum hydroxide, barium sulfate, clay, kaolin, aluminum oxide, and the like.

Generally, the pigment has an average particle size of 0.1 to 10 μm.
m. Accordingly, the particle size of the carrier is selected so that the particle size of the pigment after coating falls within this range. Since the specific surface area of the support is inversely proportional to the particle size, the amount of amorphous hydrous magnesium silicate that can be coated per unit weight of the support is a function of the particle size. For this reason, the coating amount of the amorphous hydrated magnesium silicate is expressed by the weight ratio of the carrier / coating layer to 1 /
It can vary from 10 to 10/1. The oil absorption decreases as the ratio increases, but if the coating amount of the amorphous hydrous magnesium silicate is too small, the uncoated surface of the carrier is exposed, adversely affecting rust prevention performance.

Conversely, as the coating amount of the amorphous hydrous magnesium silicate increases, the rust-preventing performance is maintained, but the effect of lowering the oil absorption decreases. Therefore, the weight ratio is 1/10 to 1 in view of the balance between the decrease in oil absorption and the retention of rust prevention performance.
It is preferably in the range of 0/1, particularly 1/5 to 6/1.

The method of preparing the pigment of the present invention into a paint and coating it on a galvanized steel sheet is described in Japanese Patent Application No. 11-7880 cited above.
This is the same as the method disclosed in No. 3.

[0016]

The following examples are for purposes of illustration and not limitation. In these,% is based on weight.

Production Example 1. TiO ₂ / MgO · SiO ₂ =
1/1 (weight ratio) 400 mL of water was put into a 1 L beaker, 14.8 g of anhydrous magnesium chloride was dissolved, and 15.6 g of titanium oxide (titanium oxide pigment JR-605 manufactured by Teica Corp.) was added thereto. . In another 200 mL beaker, place the No. 3 water glass (S
_{iO 2 29%, Na 2 O} 9.4%) placed 32.4 g, add water 75mL and diluted solution, to which 30% Na
28.5 g of an OH aqueous solution was added to make a uniform solution, and this solution was poured into the magnesium chloride solution with stirring for 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and
Wash with water, dry at 110 ° C. overnight, pulverize, 31.1 g
Was obtained as a white powder. As a result of fluorescent X-ray analysis, this white powder was found to have Ti / Mg / Si = 1.25 / 1.0 / 1.0.

Production Example 2 TiO ₂ /4MgO.5SiO
₂ = 1/1 (weight ratio) 400 mL of water was placed in a 1 L beaker, and 11.9 g of anhydrous magnesium chloride was dissolved.
4 g were added. No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%) 32.4 in another 200 mL beaker.
g, and add 75 mL of water to make a diluent.
20.2 g of a 2% aqueous solution of NaOH to make a uniform solution,
This solution was poured into the magnesium chloride solution with stirring for 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, pulverized, and dried.
8.7 g of a white powder were obtained. As a result of X-ray fluorescence analysis, this white powder was found to have Ti / Mg / Si = 1.43 / 1.0 / 1.
25.

Production Example 3 TiO ₂ /2MgO.3SiO
₂ = 1/1 (weight ratio) 400 mL of water was put into a 1 L beaker, 9.5 g of anhydrous magnesium chloride was dissolved, and 13.0 g of titanium oxide was added thereto.
g was added. In another 200 mL beaker, 31.1 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
And add 75 mL of water to make a diluent.
An aqueous NaOH solution (14 g) was added to make a uniform solution, and this solution was poured into the magnesium chloride solution with stirring for 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and
Wash with water, dry at 110 ° C. overnight, pulverize, 25.8 g
Was obtained as a white powder. As a result of fluorescent X-ray analysis, this white powder was found to have Ti / Mg / Si = 1.63 / 1.0 / 1.5.

Production Example 4 TiO ₂ / MgO · 2SiO ₂
= 1/1 (weight ratio) 400 mL of water was put into a 1 L beaker, 9.5 g of anhydrous magnesium chloride was dissolved, and 16.0 titanium oxide was added thereto.
g was added. In a separate 200 mL beaker, 41.5 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
And add 75 mL of water to make a diluent.
9.9 g of NaOH aqueous solution was added to make a uniform solution, and this solution was poured into the magnesium chloride solution with stirring for 10 minutes. The mixture was stirred for 30 minutes after pouring, and the resulting reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, pulverized,
g of a white powder were obtained. As a result of fluorescent X-ray analysis, this white powder was found to have Ti / Mg / Si = 2.0 / 1.0 / 2.0.

Production Example 5 TiO ₂ / MgO · 3SiO ₂
= 1/1 (weight ratio) 400 mL of water was put into a 1 L beaker, 6.3 g of anhydrous magnesium chloride was dissolved, and titanium oxide 14.7 was added thereto.
g was added. In a separate 200 mL beaker, 41.5 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, and pulverized to obtain 29.2 g of a white powder. As a result of X-ray fluorescence analysis,
i / Mg / Si = 2.76 / 1.0 / 3.0.

Production Example 6 TiO ₂ / MgO · 10SiO
₂ = 1/1 (weight ratio) 400 mL of water was placed in a 1 L beaker, and 2.4 g of anhydrous magnesium chloride was dissolved.
g was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 11.2 g of hydrochloric acid was added to a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
Overnight and crushed to give 31.7 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si = 8.0 / 1.0 / 9.9.

Production Example 7 TiO ₂ / MgO · 40SiO
₂ = 1/1 (weight ratio) 400 mL of water was placed in a 1 L beaker, and 0.6 g of anhydrous magnesium chloride was dissolved.
g was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 15.0 g of hydrochloric acid was put into a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
Overnight and crushed to give 30.4 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si = 30.5 / 1.0 / 39.1.

Production Example 8 TiO ₂ / MgO · 10SiO
₂ = 1/1 (weight ratio) 400 mL of water was placed in a 1 L beaker, and 6.2 g of magnesium sulfate heptahydrate was dissolved.
g was added. In another 300 mL beaker, No. 1 water glass (SiO ₂ 36.5%, Na ₂ O 18%) 41.2
g was added thereto, and 100 mL of water was added to make a diluent. This liquid was poured into the magnesium sulfate solution with stirring for 10 minutes. After stirring for 30 minutes, 9.5 g of hydrochloric acid was put into a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. 30 after casting
And the resulting reaction precipitate was filtered and washed with water,
Drying at 0 ° C. overnight and crushing gave 31.9 g of white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si was 8.1 / 1.0 / 9.8.

Production Example 9 MgO · 10SiO ₂ (without carrier) 400 mL of water was put into a 1 L beaker, and 2.4 g of anhydrous magnesium chloride was dissolved. No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.
4%), 51.7 g, and 100 mL of water were added to make a diluent.
It was poured at 0 minutes. Stir for 30 minutes after pouring, then 200 mL
The beaker was charged with 11.2 g of hydrochloric acid, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and
Washed with water, dried at 110 ° C. overnight and crushed to obtain 16 g of white powder. This white powder was analyzed by fluorescent X-ray analysis to find that M
g / Si = 0.096, and the X-ray diffraction was amorphous.

Production Example 10 TiO ₂ / MgO · 10Si
O ₂ = 1/20 (weight ratio) 400 mL of water was placed in a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 0.8 g of titanium oxide was added thereto.
Was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 11.2 g of hydrochloric acid was added to a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
Overnight and crushed to give 16.5 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si was 0.4 / 1.0 / 9.9.

Production Example 11 TiO ₂ / MgO · 10Si
O ₂ = 1/10 (weight ratio) 400 mL of water was placed in a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 1.6 g of titanium oxide was added thereto.
Was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 11.2 g of hydrochloric acid was added to a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
Overnight and crushed to give 17.4 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si = 0.8 / 1.0 / 9.9.

Production Example 12 TiO ₂ / MgO · 10Si
O ₂ = 1/5 (weight ratio) 400 mL of water was put into a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 3.2 g of titanium oxide was added thereto.
Was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 11.2 g of hydrochloric acid was added to a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
Overnight and crushed to give 19.0 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si = 1.6 / 1.0 / 9.9.

Production Example 13 TiO ₂ / MgO · 10Si
O ₂ = 1/2 (weight ratio) 400 mL of water was put into a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 8.0 g of titanium oxide was added thereto.
Was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 11.2 g of hydrochloric acid was added to a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
Overnight and crushed to give 23.7 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si = 4.0 / 1.0 / 9.9.

Production Example 14 TiO ₂ / MgO · 10Si
O ₂ = 2/1 (weight ratio) 400 mL of water was placed in a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 32 g of titanium oxide was added thereto. In another 300 mL beaker, place the No. 3 water glass (S
51.7 g of (iO ₂ 29%, Na ₂ O 9.4%) was added thereto, and 100 mL of water was added to make a diluent. The resulting solution was poured into the magnesium chloride solution with stirring for 10 minutes. Stir for 30 minutes after pouring, and then add hydrochloric acid to a 200 mL beaker.
1.2 g and 100 mL of water were added to make a diluent, which was poured into the above mixed solution in 10 minutes. After stirring, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, and pulverized to obtain 47.7 g of a white powder. This white powder was analyzed by fluorescent X-ray analysis to find that Ti / Mg / Si =
It was 19.9 / 1.0 / 9.9.

Production Example 15 TiO ₂ / MgO · 10Si
O ₂ = 4/1 (weight ratio) 400 mL of water was put into a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 64 g of titanium oxide was added thereto. In another 300 mL beaker, place the No. 3 water glass (S
51.7 g of (iO ₂ 29%, Na ₂ O 9.4%) was added thereto, and 100 mL of water was added to make a diluent. The resulting solution was poured into the magnesium chloride solution with stirring for 10 minutes. Stir for 30 minutes after pouring, and then add hydrochloric acid to a 200 mL beaker.
1.2 g and 100 mL of water were added to make a diluent, which was poured into the above mixed solution in 10 minutes. After stirring, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, and pulverized to obtain 79.8 g of a white powder. This white powder was analyzed by fluorescent X-ray analysis to find that Ti / Mg / Si =
39.8 / 1.0 / 9.9.

Production Example 16 TiO ₂ / MgO · 10Si
O ₂ = 6/1 (weight ratio) 800 mL of water was placed in a ₂ L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 96 g of titanium oxide was added thereto. In another 300 mL beaker, place the No. 3 water glass (S
51.7 g of (iO ₂ 29%, Na ₂ O 9.4%) was added thereto, and 100 mL of water was added to make a diluent. The resulting solution was poured into the magnesium chloride solution with stirring for 10 minutes. Stir for 30 minutes after pouring, and then add hydrochloric acid to a 200 mL beaker.
1.2 g and 100 mL of water were added to make a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, and pulverized to obtain 111.9 g of a white powder.
As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg / Si
= 59.9 / 1.0 / 9.9.

Production Example 17 TiO ₂ / MgO · 10Si
O ₂ = 10/1 (weight ratio) 800 mL of water was placed in a ₂ L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 160 g of titanium oxide was added thereto.
Was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 11.2 g of hydrochloric acid was added to a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
Overnight and crushed to give 176.0 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si = 80.1 / 1.0 / 9.9.

Production Example 18 TiO ₂ / MgO · 10Si
O ₂ = 20/1 (weight ratio) 800 mL of water was placed in a ₂ L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 320 g of titanium oxide was added thereto.
Was added. In another 300 mL beaker, 51.7 g of No. 3 water glass (SiO ₂ 29%, Na ₂ O 9.4%)
Was added, and 100 mL of water was added to make a diluent. This solution was poured into the magnesium chloride solution with stirring for 10 minutes.
After stirring for 30 minutes, 11.2 g of hydrochloric acid was added to a 200 mL beaker, and 100 mL of water was added to prepare a diluent, which was poured into the above mixed solution in 10 minutes. After the addition, the mixture was stirred for 30 minutes, and the obtained reaction precipitate was filtered and washed with water.
And dried overnight to give 335.7 g of a white powder. As a result of X-ray fluorescence analysis, this white powder showed Ti / Mg /
Si was 160.3 / 1.0 / 9.9.

Production Example 19 BaSO ₄ / MgO · 10S
iO ₂ = 1/1 (weight ratio) 400 mL of water was placed in a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 16 g of barium sulfate (B-30 manufactured by Sakai Chemical Industry Co., Ltd.) was added thereto. . Another 300
No. 3 water glass (29% SiO ₂ , N
a ₂ O 9.4%) placed 51.7 g, add water 100mL and diluent, stirring the liquid in the magnesium chloride solution and note down in 10 minutes. Stir for 30 minutes after pouring, then add 11.2 g of hydrochloric acid into a 200 mL beaker, add 1 ml of water
The diluted solution obtained by adding 00 mL was added to the above mixed solution in an amount of 1 mL.
It was poured at 0 minutes. The mixture was stirred for 30 minutes after pouring, and the obtained reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, and pulverized to obtain 31.7 g of a white powder. As a result of X-ray fluorescence analysis, this white powder was found to have Ba / Mg / Si = 2.7 / 1.0 /
9.9.

Production Example 20 Talc / MgO.10SiO
₂ = 1/1 (weight ratio) 400 mL of water was placed in a 1 L beaker, 2.4 g of anhydrous magnesium chloride was dissolved, and 16 g of talc (Talc SSS manufactured by Nippon Talc Co., Ltd.) was added thereto. Another 300m
No. 3 water glass (SiO ₂ 29%, Na
51.7 g of ₂ O (9.4%) was added, and 100 mL of water was added to make a diluent. The resulting solution was poured into the magnesium chloride solution with stirring for 10 minutes. After stirring, the mixture was stirred for 30 minutes, and then 11.2 g of hydrochloric acid was placed in a 200 mL beaker.
The mixture obtained by adding 0 mL to make a diluent was added to the above mixture by 10 mL.
Poured in minutes. After stirring for 30 minutes, the resulting reaction precipitate was filtered, washed with water, dried at 110 ° C. overnight, pulverized,
31.7 g of a white powder were obtained. As a result of fluorescent X-ray analysis, this white powder was found to have Mg / Si = 1.0 / 2.9.

Paint Test 1 Preparation of paint and test plate Baking-type polyester resin paints having the composition shown in the following table were prepared using the pigments of Production Examples and Comparative Examples, and after forming a coating film, a rust prevention test was performed.

Super Beckolite M-6801-30 (NV = 30%) ¹⁾ 58.7% Super Beckamine L-117-60 (NV = 60%) ²⁾ 1.7% Super Beckamine L-105- 60 (NV = 60%) ³⁾ 3.5% Titanium oxide JR-603 ⁴⁾ 16.6% Rust preventive pigment 4.2% Solvent (Solvesso 100 ⁵⁾ / isophorone / n-butanol / butyl cellosolve = 60/30 / 5/5) 15.3% 合計 Total 100.0% P / B = 1.0 PVC = 20.8 1) Oil-free polyester resin manufactured by Dainippon Ink and Chemicals 2) Butylated melamine resin manufactured by Dainippon Ink and Chemicals 3) Methylated melamine resin manufactured by Dainippon Ink and Chemicals 4) Teika White pigment 5) Exxon Chemical Ltd. aromatic solvents the coated plate: galvanized steel SGCC (manufactured by Nippon Test Panel) coating: bar coater curing conditions: baking temperature 210 ° C. (object temperature) thickness: 10 [mu] m dispersion Paint Conditioner

2. Rust prevention test (total of 20 points) 2.1 Salt spray test (total of 15 points) By forming a coating film on the plate under the above coating conditions
To the surface of the plate to be coated with a cutter knife
And put the salt in the tank at 35 ° C
Leave it in the water spray tester, 5% aqueous solution of sodium chloride
1kg / cm ^TwoSpray on the coating film for 56 days at the pressure of
Observe the raw condition and swelling of the coating film, and
It was evaluated based on: In addition, the corrosion state is
Evaluation was made based on the generation area and the corrosion width of the cut portion. Either
In the evaluation, the higher the rating, the better the rust prevention
You.

Evaluation criteria for rust prevention effect (based on ASTM D610-68 (1970))平面 Flat part Rust occurrence area Less than 0.1%: 5 points Rust occurrence area 0.1% or more to less than 1%: 4 points Rust occurrence area 1% or more to less than 10%: 3 points Rust occurrence area 10% or more to less than 33%: 2 points Rust generation area 33% or more: 1 point ─────────────────────────────── ────

Evaluation criteria for blister prevention effect (based on ASTM D-714-59 (1965))平面 Flat part 8F or less: 5 points 8M, 6F: 4 points 8MD, 6M, F: 3 points 8D, 6MD, 4M, 2F: 2 points 6D, 4MD or more, 2M or more: 1 point Cut Part, end face Corrosion width 0-1 mm: 5 points Corrosion width 1-2 mm: 4 points Corrosion width 2-3 mm: 3 points Corrosion width 3-4 mm: 2 points Corrosion width 4-5 mm: 1 point ─────────────────────────────

2.2 Moisture resistance test (out of 5 points)
The film was allowed to stand still for 56 days in a humidity resistance tester maintained at a relative humidity of 95% or more, and the swelling of the coating film was observed.

3. Dispersibility test In the above-mentioned coating, the dispersibility was evaluated by the time (minute) until the pigment was dispersed to 10 μm or less by a paint conditioner. Judgment of 10 μm or less is J
The measurement was performed according to the degree of dispersion (distribution diagram) of IS K 5400.

4. Paint viscosity The viscosity (mPa · s) of the paint immediately after preparation was measured using a rotational viscometer (60 rpm).

5. Gloss The specular gloss (60 degrees) of the coated plate before being subjected to the rust prevention test was measured.

6. Results The results are shown in the table below.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

7. Consideration The carrier / coating weight was kept constant at 1/1, and the Mg
In Production Examples 1 to 8 in which the / Si atomic ratio was changed, the dispersibility, viscosity, and gloss were all excellent in comparison with the amorphous hydrous magnesium silicate powder of Production Example 9. However, it shows that a product having an Mg / Si atomic ratio of 2/3 or less is preferable in terms of rust prevention.

Production Examples 9 to 10 in which the Mg / Si atomic ratio of the coating was kept constant at 1/10 and the weight ratio of the carrier / coating was changed.
18 shows that as the weight ratio decreases, the product approaches the product of Production Example 9 in all items, and conversely, as the weight ratio increases, it approaches the carrier TiO ₂ . The weight ratio of carrier / coating is preferably in the range of 1/5 to 6/1, from the balance between rust prevention and other performances.

Also in Production Examples 19 and 20 in which the carrier was changed to BaSO ₄ and talc instead of TiO ₂ , rust-proofing properties comparable to those of Production Example 6 in which the carrier / coating weight ratio and the Mg / Si atomic ratio were the same, Dispersibility, viscosity and gloss were obtained and, of course, Comparative Example 2 of the carrier alone of these products
Rust prevention is better than that of Nos. 3 and 3.

Further, in Comparative Example 4, the rust-proofing property is rather deteriorated simply by dry-mixing the carrier TiO ₂ with the hydrated amorphous hydrous magnesium silicate, and the dispersibility and other improvements are not sufficient.

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) C09C 1/42 C09C 1/42 3/06 3/06 (72) Inventor Minoru Ishihara 1-chome, Funamachi, Taisho-ku, Osaka-shi, Osaka No. 47 No. 47 Teica Co., Ltd. F term (reference) 4J037 AA09 AA22 AA24 AA25 AA27 CA25 DD05 EE03 EE28 EE29 EE33 EE35 EE43 FF24 4K062 AA01 BA14 CA02 DA05 FA12 GA02 GA08

Claims (4)

[Claims] An anticorrosive pigment for a galvanized steel sheet, wherein the surface of a dense inorganic carrier is coated with an amorphous hydrous magnesium silicate compound having an Mg / Si atomic ratio of 0.025 to 1.0. 2. The pigment according to claim 1, wherein the atomic ratio of Mg / Si is 0.025 to 0.8. 3. The pigment according to claim 1, wherein the coating amount of the amorphous hydrous magnesium silicate compound is 1/10 to 10/1, expressed as a weight ratio of inorganic carrier / amorphous hydrous magnesium silicate. 4. The pigment according to claim 1, wherein the inorganic carrier is a crystalline particle selected from titanium dioxide, talc, aluminum hydroxide, clay, barium sulfate, kaolin and aluminum oxide.