JP2000053406A - Magnesium aluminum phosphite pigment and coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nontoxic rust preventive pigment and a rust preventive coating material having excellent rust preventing property and stability of the coating material because a conventional nontoxic rust preventive pigment or a rust preventive coating material does not have enough rust preventing property or stability of the coating material compared to chromate compds. or lead compds. SOLUTION: This pigment essentially consists of a magnesium aluminum phosphite multiple salt containing 0.01 to 0.5 mol carbonate groups per 1 mol of phosphite group. Further, the pigment essentially consists of the magnesium aluminum phosphite multiple salt in which aluminum is partly substituted with at least one kind of metal selected from lithium, zinc, calcium and strontium, the molar ratio of the substituting metals to magnesium ranges 0.1 to 10 and the molar ratio of all substituted metals to phosphite groups ranges 0.5 to 5. The coating material contains the pigment above described.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-toxic pigment having excellent rust-preventing action, and a rust-preventive paint using the pigment. Conventionally, chromic acid compounds and lead compounds have been widely used as rust preventive pigments. However, the toxicity of chromium and lead contained therein has become a problem, and non-toxic rust preventive pigments have been developed. As a result, protection mainly comprising metal phosphates such as zinc phosphate, condensed phosphates such as aluminum tripolyphosphate, phosphites such as zinc phosphite, and molybdates such as zinc molybdate. Rust pigments have been developed. However, none of these compounds had rust-proofing properties comparable to chromic acid compounds and lead compounds. The present invention relates to a pigment having no toxicity to the human body, having a low water-soluble content, and having a superior rust-preventive action, and a rust-preventive paint using the pigment. .

[0002]

2. Description of the Related Art Conventionally, phosphite has been studied as a rust preventive pigment. For example, JP-A-58-84109 discloses that potassium zinc phosphite is useful as a pollution-free rust preventive paint.
No. 5 discloses that a zinc hydroxyphosphite complex is superior to basic zinc phosphite in chemical stability and dispersibility. Also, Japanese Patent Application Laid-Open No. 59-204
No. 663 discloses that basic potassium zinc phosphite is particularly useful as a pollution-free rust preventive paint, and Japanese Patent Publication No. 6-504978 discloses a basic calcium hydroxy phosphite. It is disclosed that aluminum is useful as a PVC stabilizer.

The present inventors have disclosed in Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 57-285808 discloses that zinc calcium phosphite has excellent rust prevention properties.
In the publication, it was disclosed that calcium phosphite having a plate-like crystal had particularly excellent rust prevention properties. JP-A-6-57168 discloses that zinc calcium phosphite containing a small amount of zinc molybdate and the like is excellent as a rust-preventive pigment that can be used for a wide range of paints,
JP-A-7-232907 discloses that zinc strontium phosphite is more excellent in paint stability and rust prevention.

[0004]

The above-mentioned zinc calcium phosphite and zinc strontium phosphite are considerably improved in rust-preventive properties, but they are more effective than conventional chromate compounds and lead compounds. The rust resistance and paint stability are not yet sufficient, and it is necessary to use some amount of the rust-preventive pigment and the amount of the stabilizer. It is an object of the present invention to provide a pigment having higher rust prevention and higher paint stability, and a paint using the pigment.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have proposed that 0.01 mol per 1 mol of phosphite groups.
A pigment mainly composed of magnesium aluminum phosphite double salt containing up to 0.5 mol of a carbonic acid group (hereinafter referred to as "first invention"), and a part of magnesium of magnesium phosphite is aluminum or aluminum; ,lithium,
With one or more metals selected from the group consisting of zinc, calcium, and strontium, the molar ratio of the substituted metal to magnesium is in the range of 0.1 to 10, and the molar ratio of the total metal to the phosphite group is from 0.1 to 10. A pigment containing a substituted magnesium aluminum phosphite double salt as a main component in a ratio of 0.5 to 5 (hereinafter referred to as a "second invention"), and a pigment according to the first invention or a second invention And a paint containing the pigment according to the above (hereinafter referred to as "third invention").

[0006] The pigment according to the first invention is mainly composed of a magnesium aluminum phosphite double salt,
This double salt includes basic ones, and is characterized in that a carbonate group is contained in an amount of 0.01 to 0.5 mol per 1 mol of a phosphite group. The reason why the carbonic acid group is required is that the solubility of magnesium phosphite is high and it is difficult to reduce the water-soluble content to 2% or less even as a double salt with aluminum phosphite. Is to increase. When the concentration of the carbonic acid group is less than 0.01 mol, sufficient insolubilization is not recognized, and no excessive insolubilization is required up to more than 0.5 mol. The introduction of the carbonate group is usually supplied from magnesium carbonate or another carbonate used as a raw material. The pigment according to the first invention includes, in addition to the magnesium aluminum phosphite double salt, zinc phosphate,
Calcium phosphate, aluminum phosphate, barium metaborate, zinc molybdate, calcium molybdate,
Pigments such as zinc phosphite, zinc calcium phosphite, strontium zinc phosphite, and zinc oxide may be included.

[0007] The magnesium aluminum phosphite double salt according to the first invention is usually produced by reacting at 50 ° C or lower in a carbon dioxide atmosphere using a reactor having a mechanochemical effect such as a ball mill. In this carbon dioxide atmosphere, carbon dioxide generated by a reaction of a carbonate such as magnesium carbonate can be used.

The pigment according to the second invention is characterized in that a part of magnesium of magnesium phosphite has a molar ratio of aluminum to magnesium in the range of 0.1 to 10;
A magnesium aluminum phosphite double salt substituted with aluminum (hereinafter referred to as "double salt A") in a molar ratio of all metals to phosphite groups in the range of 0.5 to 5,
Alternatively, a part of magnesium of magnesium phosphite has a molar ratio of the substituted metal to magnesium of 0.1 to
In the range of 10 and the molar ratio of all metals to phosphite groups is in the range of 0.5 to 5, aluminum, lithium,
Magnesium aluminum phosphite double salt substituted with one or more metals selected from the group consisting of zinc, calcium, and strontium (hereinafter, “double salt B”
These double salts include basic ones, and about 0.01 to 0.5 mol of carbonic acid groups remain per 1 mol of phosphite groups. Is preferred. Therefore, pigments having a double salt A as a main component and having a carbonate group remaining in the double salt include the same pigments as the pigment according to the first invention. The molar ratio of other metals to magnesium in these double salts was 0.1
If it is less than 10, hardly soluble ones cannot be obtained. Further, even if the molar ratio of the total metal to the phosphite group is less than 0.5,
If it exceeds 5, the stability and rust resistance of the double salt are undesirably reduced. In addition, the double salt B is such that by adding a metal other than aluminum, crystallization of the double salt is suppressed and fine particles can be easily formed. Further, the pigment according to the second aspect of the present invention includes, as in the pigment according to the first aspect,
Other pigments may be included.

In the synthesis of these double salts, phosphite, aluminum phosphite, oxides, hydroxides and carbonates of other metals are used. In addition, it is better not to use a reaction product such as a sulfate which may leave a different acid radical. Phosphites other than aluminum phosphite are:
It is not preferable because the reaction with the aluminum raw material is difficult and a double salt is hardly generated. In the case of reacting phosphorous acid with a metal salt, it is preferable to react the phosphorous acid with an aluminum salt in advance and then react with another metal salt. Further, as the metal salt of the raw material, 0.1 mol or more of the carbonate relative to the phosphite is used so that about 0.01 to 0.5 mol of the carbonate group remains in the double salt. Is preferred. This carbonate is preferably added and reacted at the end of the reaction or at the time of the mechanochemical reaction.

The paint according to the third invention is characterized by containing the pigment according to the first invention or the pigment according to the second invention. These pigments may be those containing the magnesium aluminum phosphite double salt contained therein as a main component as they are, and furthermore, this double salt may contain rustproofing such as cobalt, nickel, tin, copper, and molybdenum. A material carrying a metal having properties and a curing catalyst function of a coating resin may be used. In addition to these pigments, paint additives such as titanium oxide, stearate, hydrotalcite, silicon oxide, calcium carbonate, talc, kaolin, barium sulfate and the like may be added.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Manufacture of pigment [Example 1] 50% phosphorous acid solution (H
572 g of ₃ PO ₃ ) was placed in a 2 liter beaker, and 90.6 g of aluminum hydroxide (Al (OH) ₃ ) was reacted with stirring, followed by 70.2 g of magnesium oxide (MgO).
And basic magnesium carbonate (MgCO ₃ · Mg (OH)
₂ · _{3H 2} O) _212.2g and gradually reacted addition of 25% slurry 1130g containing dispersed, after cooling, the slurry of the reaction was transferred into an alumina 2l ball mill, 1
The reaction was completed by mixing for 6 hours. The resulting slurry had a pH of 8.3. This slurry was filtered, and the obtained filter cake was dried at 200 ° C. for 10 hours to obtain a powder (hereinafter, referred to as “Pigment 1”).

Example 2 544.4 g of a 70% phosphorous acid solution (H ₃ PO ₃ ) heated to 50 ° C. was placed in a futaba kneader, and aluminum hydroxide (Al (OH) ₃ ) 2 was added thereto.
After reaction by adding 07.2G, while kneading, basic magnesium carbonate _{(MgCO 3 · Mg (OH)} 2 · 3
H ₂ O) to obtain a gradually added and reacted powder 121.3 g. This powder was transferred to a 2 liter bead mill, 1000 g of water was added, and the mixture was kneaded at 30 ° C. for 5 hours to complete the reaction. The resulting slurry had a pH of 6.2. This slurry was treated in the same manner as in Example 1 to obtain a powder (hereinafter referred to as “Pigment 2”).
I got

Example 3 644 g of a 30% phosphorous acid solution (H ₃ PO ₃ ) heated to 70 ° C. was placed in a 2 liter beaker, and stirred with aluminum hydroxide (Al (O 2)).
H) ₃ ) 183.8 g and magnesium oxide (MgO) 9
4.9g and strontium carbonate _(SrCO 3) 521.
After reacting at 70 ° C. for 2 hours, 30 g
The mixture was cooled to ° C and transferred to an alumina 2L ball mill, and kneaded for 15 hours to complete the reaction. The resulting slurry has a pH
9.3. This slurry was treated in the same manner as in Example 1 to obtain a powder (hereinafter, referred to as “Pigment 3”).

Example 4 1291.5 g of a 20% phosphorous acid solution (H ₃ PO ₃ ) heated to 40 ° C. was placed in a disper mill, and aluminum hydroxide (Al (OH) ₃ ) 4 was added.
9.1g of calcium carbonate _(CaCO 3) 63.0 g and zinc oxide (ZnO) 102.6 g and a basic magnesium carbonate _{(MgCO 3 · Mg (OH)} 2 · 3H 2 O) 17
After adding 2.6 g, the mixture was kneaded for 5 hours to complete the reaction. The resulting slurry had a pH of 8.5. This slurry was treated in the same manner as in Example 1 to obtain a powder (hereinafter referred to as “Pigment 4”).
).

Example 5 1300.5 g of a 20% phosphorous acid solution (H ₃ PO ₃ ) heated to 30 ° C. was placed in a stirred layer mill (trade name “Attritor”), and aluminum hydroxide (Al) was added. (OH) ₃ ) 38.6 g and zinc oxide (ZnO) 1
78.8 g and basic magnesium carbonate (MgCO ₃ · M
_{g (OH) 2 · 3H 2} O) was added and 133.7g, 8
The reaction was completed by mixing for a time. The resulting slurry is p
H8.5. This slurry was treated in the same manner as in Example 1 to obtain a powder (hereinafter, referred to as "Pigment 5").

Example 6 891.3 g of a 40% phosphorous acid solution (H ₃ PO ₃ ) heated to 60 ° C. was placed in a 2 l beaker and aluminum hydroxide (Al (OH) ₃ ) 169.6 was added.
g and reacted sufficiently, then lithium carbonate (L ₂ iCO
₃ ) 80.2 g and basic magnesium carbonate (MgCO _{3
· Mg (OH) 2 · 3H} 2 O) 49.2g reacted by adding, stirring for 2 hours the slurry, after stabilizing cooled and transferred to an alumina 2l ball mill, further, basic magnesium carbonate 50g And 500 g of water were added and kneaded for 20 hours to complete the reaction. The resulting slurry has a pH of 7.8.
Met. This slurry was treated in the same manner as in Example 1 to obtain a powder (hereinafter, referred to as "Pigment 6").

Example 7 363.3 g of a 60% phosphorous acid solution (H ₃ PO ₃ ) heated to 50 ° C. was placed in a futaba kneader, and aluminum hydroxide (Al (OH) ₃ ) 103.
9 g was added and reacted to prepare an aqueous solution of aluminum phosphite, and then 49.2 g of lithium carbonate (Li ₂ CO ₃ ).
And zinc oxide (ZnO) 271.1 g were added to obtain a powder. This powder and basic magnesium carbonate (MgCO _{3
Mg (OH) 2 · 3H 2} O) 60.8g and water 1000g
Was transferred to an alumina 2 l ball mill and kneaded for 20 hours to complete the reaction. The resulting slurry had a pH of 6.8. This slurry was treated in the same manner as in Example 1 to obtain a powder (hereinafter, referred to as “Pigment 7”).

[Comparative Examples] As pigments for comparing properties such as rust resistance, commercially available zinc chromate-based (ZTO type) pigments (hereinafter referred to as "Pigment 8") and strontium chromates (hereinafter referred to as "Pigment 9"). ), Zinc phosphate (hereinafter referred to as "Pigment 10"), zinc molybdate (hereinafter referred to as "Pigment 11")
Strontium zinc phosphite (hereinafter referred to as “Pigment 1
2 ") and talc (hereinafter referred to as" pigment 13 ").

2. Analysis results of pigments Table 1 shows the analysis results of the pigments 1 to 7 manufactured in Examples 1 to 7 and the pigments 8 to 13 prepared in Comparative Examples. In Table 1, the metal ion was determined by atomic absorption spectrometry, the phosphorus was determined by colorimetric absorption using molybdic acid, and the carbonate group was represented by
The barium salt was analyzed by a gravimetric method. The water-soluble component was determined according to JIS K5101-91 pigment test method. From the results in Table 1, the pigments 1 to 1 produced in Examples 1 to 7 were obtained.
No. 7 almost matched the raw material composition, and it was confirmed that the target compound was synthesized. However, the content of the carbonate group was lower than expected. The water-soluble content was slightly higher than that of the commercially available rust preventive pigment, but was lower than that of the conventional phosphite-based rust preventive paint.

[0020]

[Table 1]

3. Manufacture of a water-soluble epoxy ester resin-based paint Pigments 1 to 7 manufactured in Examples 1 to 7 and pigments 8 to 13 prepared in Comparative Examples were blended according to the formulations in Table 2, respectively.
Further, 100 g of glass beads (φ1.5 mm) was added, and the mixture was dispersed in a sand mill for 30 minutes to form a paint, thereby obtaining paints (hereinafter, referred to as “paint A1” to “paint A13”). The water-soluble epoxy ester resin used here is “Watersol CD-540” manufactured by Dainippon Ink and Chemicals, Inc., a resin having a nonvolatile content of 39.2%.
In producing the coatings A1 to A13, there was no particular problem, and there was no particular problem in the stability of the obtained coating.

[0022]

[Table 2]

4. Manufacture of an air-drying acrylic emulsion resin-based paint Pigments 1 to 7 manufactured in Examples 1 to 7 and pigments 8 to 13 prepared in Comparative Examples were blended in the formulations shown in Table 3, respectively.
Further, 100 g of glass beads (φ1.5 mm) was added, and the mixture was dispersed in a sand mill for 30 minutes to form a paint, thereby obtaining paints (hereinafter, referred to as “paint B1” to “paint B13”). However, paints of pigment 8, pigment 11, and pigment 12 were gelled and could not be used as paints. The normally-drying acrylic emulsion resin used here is "Aromatex E-208" manufactured by Mitsui Toatsu Chemicals, Inc. and has a nonvolatile content of 45%. In addition, pigments 1 to 7 produced in Examples 1 to 7 and pigments 9 to 10 and pigment 13 prepared in the comparative example do not have any particular problem in the preparation of a paint, and the stability of the obtained paint is also low. There was no particular problem.

[0024]

[Table 3]

[5] Rust prevention test Paints A1 to A13, paint B1 obtained as described above
To B7, paints B9, B10, and B13, respectively, were cold-rolled steel plates (JISG314) manufactured by Japan Test Panel Co., Ltd.
2) One coat was applied to 1.0 × 70 × 150 mm using a bar coater to adjust the film thickness after drying to 30 μm, and then dried at room temperature for one week without overcoating. A rust prevention test plate was prepared for each paint. These rust prevention test plates were attached to a salt spray tester (ST-ISO-3) manufactured by Suga Test Instruments Co., Ltd.
A 0 hour salt spray test was performed. The results are as shown in Table 4. The evaluations in Table 4 are as follows: 1 indicates that rust is generated over the entire rust prevention test plate, 2 indicates that rust is generated at 75 to 51% of the rust prevention test plate, and 3 indicates that rust is generated. 4 means 50% to 26% of the plate, 4 means less than 25% of the rust preventive test plate, and 5 means no rust or blister. From Table 4, it can be seen that the pigments (Pigments 1 to 7) according to the present invention can be used for both water-soluble epoxy ester paints and air-drying acrylic emulsion paints. It can be seen that the paints concerned (Paints A1 to 7 and Paints B1 to 7) have rust-prevention properties equal to or higher than those of commercially available zinc chromate paints and strontium chromate paints.

[0026]

[Table 4]

The pigment according to the present invention has no toxic property and has excellent rust-preventive properties, and can be used for various paints. The paint according to the present invention using the pigment according to the present invention is: Non-toxic and has the same or higher rust-preventive properties as conventional chromate paints, so it can be widely used as a paint for furniture, toys, electrical appliances, automobiles, etc. with a sense of security and greatly contributes to the maintenance of public health It is.

Claims (3)

[Claims] (1) 0.01 to 1 mol of phosphite group
Pigment based on magnesium aluminum phosphite double salt containing 0.5 mol of carbonate group 2. A method according to claim 1, wherein a part of magnesium of the magnesium phosphite is substituted with magnesium by aluminum or aluminum and one or more metals selected from the group consisting of lithium, zinc, calcium and strontium. When the molar ratio of the metal is in the range of 0.1 to 10,
The molar ratio of the total metal to the phosphite group is 0.5 to 5
A pigment mainly comprising a substituted magnesium aluminum phosphite double salt in the range of 3. A paint containing the pigment according to claim 1 or 2.