JP2002294161A - Coating material composition containing rust preventive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To find out a coating material composition which does not contain any harmful metal such as lead or chromium, is nontoxic or lowly toxic, and has good anticorrosiveness. SOLUTION: This coating material composition contains a metal phosphate of ascorbic acid, represented by the formula: [C6 H6 O5 (PO4 )]3/n M<n+> (wherein M<n+> is a metal with a valence of 1 to 3; and (n) is an integer].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-polluting or low-pollution coating composition containing a metal phosphate of ascorbic acid and having excellent anticorrosion properties.

[0002]

2. Description of the Related Art As an rust preventive pigment or rust preventive used in an organic solvent type paint composition or an aqueous paint composition, a lead-based paint (for example, leadtan, Basic lead silicate, lead cyanamide, calcium lead acid,
Chromium (such as zinc chromate,
Strontium chromate) are known.

[0003] However, these rust preventive pigments and rust preventives are very harmful substances, and there is a problem in using them due to pollution control and influence on the human body. Instead of toxic lead compounds and chromium compounds, non-toxic or low-toxic rust-preventive pigments and rust inhibitors have been studied, but we have not found one that has the same rust-preventing ability as the lead compounds and chromium compounds described above. In addition, those having rust-preventing ability have problems to be improved, such as lowering storage stability and aging stability with respect to some resin-based coating compositions.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to find a non-toxic or low-toxic rust inhibitor that does not contain harmful metals such as lead and chromium. It has been found that the above problems can be solved by adding an acid metal salt to the coating composition, and the present invention has been completed.

That is, the present invention provides: A coating composition containing a metal phosphate of ascorbic acid represented by the following structural formula (1).

[0006]

Embedded image Structural formula (1)

(M represents a metal having 1 to 3 valences, and n represents 1 to 3
Indicates an integer. ) 2. 2. The coating composition according to claim 1, wherein in the metal phosphate of ascorbic acid represented by the structural formula (1), M is Mg ascorbic acid, magnesium phosphate. 3. 2. The coating composition according to item 1, wherein in the metal phosphate of ascorbic acid represented by the structural formula (1), M is sodium phosphate of ascorbic acid of Na.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the composition of the present invention will be described in detail. The present invention relates to a coating composition to which a metal salt of a phosphoric acid derivative of ascorbic acid is applied as a rust inhibitor.

[0009] Ascorbic acid (L-ascorbic acid is known as vitamin C) and derivatives of ascorbic acid are used in foods and drinks, pharmaceuticals, quasi-drugs, feed, cosmetics and the like without any processing. Is known to be unstable and easily oxidatively decomposed by oxygen or light in the air. In particular, since it is very unstable near neutrality, it is often used in anticipation of a certain degree of decomposition. Therefore, many attempts have been made to develop ascorbic acid derivatives having excellent stability.

The present invention relates to the discovery of a rust preventive having good stability by adding a compound called a metal salt of a phosphoric acid derivative of ascorbic acid to an organic solvent type coating composition and an aqueous coating composition. The phosphoric acid derivative metal salt of ascorbic acid is represented by structural formula (1).

[0011]

Embedded image Structural formula (1)

(M represents a metal having 1 to 3 valences, and n represents 1 to 3
Indicates an integer. The metal corresponding to M in the structural formula (1) includes an alkali metal ion, an alkaline earth metal ion, and a transition metal ion. Examples of the alkali metal ion include L
i ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , and Cs ⁺ . Among them, Na ⁺ and K ⁺ are preferable.

As alkaline earth metal ions, for example,
If, Be²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺Etc.
Can be Among them, Mg²⁺, Ca²⁺Is preferred. Transition gold
Genus ion, Zr²⁺, Mn²⁺, Ni²⁺, Co²⁺, C
u²⁺, Zn²⁺, W³⁺, Mo³⁺, Fe ³⁺Such as amphoteric metal
Al ions³⁺Is mentioned. Specifically,
Scorbic acid magnesium phosphate, ascorbic acid
Sodium phosphate, ascorbic acid calcium phosphate
And strontium phosphate of ascorbic acid
Can be

The case where a metal salt of a phosphoric acid derivative of ascorbic acid is blended in the organic solvent coating composition is as follows.
If it can be dissolved in the organic solvent in the coating composition, it can be added together with the base resin and the curing agent at the time of preparing the coating composition, or can be dissolved in the manufactured coating composition and added together with the organic solvent. .

Those partially dissolved or insoluble in an organic solvent are:
It can be used as a pigment paste by blending it with a base resin or a curing agent when preparing the coating material, or by dispersing it together with a dispersing resin, other pigments, additives, and the like.

For example, a metal salt of a phosphoric acid derivative of ascorbic acid is easily dissolved in an organic solvent having a hydroxyl group such as alcohol, and is uniformly dispersed in a coating composition or a coating film.
Due to the distribution, the effect as a rust inhibitor is also large. Also,
Among the phosphoric acid derivative metal salts of ascorbic acid, magnesium phosphate of ascorbic acid in which M is Mg and sodium phosphate of ascorbic acid in which M is Na in the structural formula (1) are preferable.

As the organic solvent type paint to which the phosphoric acid derivative metal salt of ascorbic acid is added, specifically, an acrylic resin paint, an alkyd resin paint, a polyester paint,
Epoxy resin paint, amino resin paint (melamine resin, benzoguanamine resin, urea resin and paint system using methylolated or alkyl etherified amine compound), cellulose derivative paint (nitrocellulose lacquer, acetylcellulose lacquer, acetylbutylcellulose) Lacquer, ethylcellulose lacquer, etc.),
Examples include urethane resin paints, vinyl chloride resin paints, fluororesin paints, vinyl acetate resin paints, styrene-butadiene resin paints, and vinyl chloride organosol paints.

The organic solvent type paint used in the present invention is not particularly limited, whether it is a non-crosslinking type (a coating film is formed by evaporating a solvent like a lacquer type) or a crosslinking type. Can be used for

As the cross-linking type, any of a thermosetting coating and a room temperature setting coating can be used. The thermosetting coating composition is, for example, a hydroxyl group-containing resin (acrylic resin, acrylic resin,
Conventionally known cross-linkable types such as epoxy resin, polyester, etc./curing agent (amino resin, blocked polyisocyanate compound), polycarboxylic acid resin / epoxy resin curing agent, epoxy resin / polycarboxylic acid curing agent, etc. can be used. .

The organic solvent used in this organic solvent paint is
Hydrocarbon-based (eg, xylene, toluene, hexane,
Heptane), alcohols (e.g., methol alcohol, n-butyl alcohol, isopropyl alcohol,
2-ethylhexyl alcohol, ethylene glycol,
Propylene glycol), ethers (for example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol monoethyl ether,
3-methyl-3-methoxybutanol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether), ketones (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, acetylacetone), ester (for example, ethyl acetate, butyl acetate) Propyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate) and mixtures thereof.

The content of the organic solvent in these organic solvent paints is about 10 to 95% by weight, preferably about 20 to 90% by weight, based on the total weight of the organic solvent paint. Also, if necessary, a flow control agent, a plasticizer, a curing catalyst, a surface control agent,
An ultraviolet absorber, a light stabilizer, a pigment paste and the like can also be blended.

As the pigment of the above-mentioned pigment paste, conventional pigments can be used without limitation, for example, titanium oxide, carbon black, zinc yellow, red iron oxide, aluminum paste, pearl powder, graphite, MIO, copper phthalocyanine blue, quinacridone Inorganic and organic coloring pigments such as red; extenders such as clay, mica, barita, talc, calcium carbonate, and silica; and rust prevention such as zinc phosphate, zinc molybdate, zinc dust, iron phosphate, bismuth compounds, etc. Pigments.

The amount of the phosphoric acid derivative metal salt of ascorbic acid to be added to the coating composition is 0.01 to 50 parts by weight, preferably 0.0 to 50 parts by weight, based on 100 parts by weight of the solid content of the resin.
The range is preferably 5 to 30 parts by weight, more preferably 1 to 10 parts by weight. If the added amount is less than 0.01 part by weight, there is no effect on the anticorrosion property, and if it exceeds 50 parts by weight, the stability of the organic solvent type coating composition is undesirably deteriorated.

Next, the case where a metal salt of a phosphoric acid derivative of ascorbic acid is applied to an aqueous paint will be described below.

The metal salt of a phosphoric acid derivative of ascorbic acid, which is represented by the structural formula (1), has different solubility in water depending on the compound, but is generally soluble or partially soluble in water. It is mixed with a base resin and a curing agent at the time of preparing the coating material, or dispersed together with a dispersing resin, other pigments, additives and the like, and used as a pigment paste.

The magnesium phosphate of ascorbic acid is
It is easily soluble in solvents such as water and alcohol, and can be dissolved in water-dispersed resins and emulsions and added to aqueous paints. Since magnesium phosphate of ascorbic acid has low toxicity and is often used in cosmetics, it can be easily handled when formulating paints.

The sodium phosphate of ascorbic acid, like the magnesium phosphate of ascorbic acid, is easily soluble in solvents such as water and alcohol, and may be dissolved in a water-dispersed resin or emulsion and added to the aqueous coating composition. It is possible. Ascorbic acid sodium phosphate is also less toxic and is often used as cosmetics.
It can be easily handled at the time of blending the aqueous coating composition and the like.

As the water-based paint, anion-type, cationic-type, and nonion-type such as conventionally known water-soluble, water-dispersed, and emulsion-type paints can be used. The amount of addition is 0.01 to 50 parts by weight per 100 parts by weight of the resin solid content.
It is preferably in the range of 0.05 to 30 parts by weight, more preferably 1 to 10 parts by weight. The amount added is 0.01
If the amount is less than 50 parts by weight, there is no effect on the corrosion resistance, and if it exceeds 50 parts by weight, the stability of the water-based paint is impaired.

Examples of the aqueous paint include acrylic resin paints, alkyd resin paints, polyester paints, epoxy resin paints, amino resin paints (melamine resin, benzoguanamine resin, urea resin and methylol of amine compound). Paints using a compound or an alkyl ether compound), urethane resin paints, vinyl chloride resin paints, fluororesin paints, vinyl acetate resin paints, styrene-butadiene resin paints, and the like.

The water content in the coating composition is about 10
~ 95% by weight, preferably about 20-90% by weight.
If necessary, a water-based paint is prepared by blending a flow control agent, a plasticizer, a curing catalyst, a surface control agent, an ultraviolet absorber, a pigment paste and the like.

As the pigment used in the above-mentioned pigment paste, conventional pigments can be used without limitation as in the case of organic solvent type paints. Examples thereof include titanium oxide, carbon black, zinc yellow, red iron, aluminum paste, and pearl powder. And inorganic or organic coloring pigments such as graphite, MIO, copper phthalocyanine blue, and quinacridone red; extenders such as clay, mica, barita, talc, calcium carbonate, silica; and zinc phosphate, zinc molybdate, zinc dust, phosphorus Rust-preventive pigments such as iron acid are exemplified. Also,
In addition to the organic solvent-based paints and water-based paints described above, solventless liquid paints, active energy ray-curable paints, and powder paints can also be used. The above coating composition is aluminum,
Good anti-corrosion properties are exhibited when a hardened coating is formed by applying it to a metal substrate such as steel, zinc, tin, copper, and stainless steel, particularly to a steel substrate, and then heating at room temperature.

Also, a plated metal substrate obtained by plating zinc, tin, aluminum, chromium, etc. on the surface of steel, a chemical conversion metal substrate obtained by treating the surface of steel or the like with chromic acid, phosphoric acid, or the like can be used. .

The coating method of the coating composition includes, for example, brush coating, spray spray coating, roller coating, dip coating,
It can be applied to the substrate surface by means such as electrostatic powder coating and electrodeposition coating. The amount of coating varies depending on the type of coating, coating means, purpose of use, etc., but is generally about 0.1 to 500 μm.
Range.

The conditions for drying the coating film can be selected according to the type of the coating composition. For example, an acrylic resin-based coating composition containing a hydroxyl group-containing acrylic resin as a base resin and a blocked polyisocyanate compound or an amino resin as a cross-linking agent has a temperature of 10 ° C. at 80 ° C. to 250 ° C.
It is considered that about 120 seconds to 120 minutes is sufficient.

[0035]

Industrial Applicability The present invention provides a cured coating film excellent in anticorrosion properties by incorporating a metal salt of a phosphoric acid derivative of ascorbic acid, particularly magnesium phosphate of ascorbic acid and sodium phosphate of ascorbic acid into a coating composition. And has an effect of replacing harmful metals such as lead and chromium as a rust preventive in pollution-free paints.

The reason why the metal salt of the phosphoric acid derivative of ascorbic acid exhibits an excellent rust-preventive action is that metal ^ions such as Fe ³⁺ , Al ³⁺ , Zn ²⁺ eluted from the metal member and the metal phosphate of ascorbic acid are used. Is chelated and deposited on the metal surface to form a passivating film of a metal phosphate on the surface to suppress corrosion, and oxygen ions and chlorine ions of corrosion factors invading from the outer surface of the coating film. Is considered to be effective in preventing corrosion by preventing these corrosion factors from migrating to the interface between the coating film and the metal member.

[0037]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited by this. Note that “parts” and “%” indicate “parts by weight” and “% by weight”.

Production Example of Pigment Paste (A) 100 parts of Acridic A801 (manufactured by Dainippon Ink and Chemicals, Inc., trade name, acrylic resin) in a stirring and mixing vessel,
JR-701 (manufactured by Teica Corporation, trade name, titanium white)
80 parts, 20 parts of Tancal 200 (trade name, calcium carbonate, manufactured by Takehara Chemical Co., Ltd.), 5 parts of magnesium phosphate of ascorbic acid, and a xylene-based solvent were added, and the mixture was dispersed for 60 minutes using a tabletop sand mill. A pigment paste (A) having a solid content of 30% by weight was obtained.

Production Example of Pigment Paste (B) The same procedure as in the production example of the pigment paste (B) was carried out except that 5 parts of sodium phosphate of ascorbic acid was added. % By weight of the pigment paste (B) was obtained.

Production Example of Pigment Paste (C) The same procedure as in the production example of the pigment paste (C) was carried out except that 5 parts of calcium phosphate of ascorbic acid was added. By weight, a pigment paste (C) was obtained.

Production Example of Pigment Paste (D) In the above Production Example, except that the phosphoric acid derivative metal salt of ascorbic acid was not blended, the solid content of the organic solvent type coating composition was 30% by weight. Pigment paste (D)
I got

Production Example of Pigment Paste (E) 10 parts of BYK-184 (manufactured by BYK Chemie, pigment dispersant) in a stirring and mixing vessel, 80 parts of JR-701 (manufactured by Teica, trade name, titanium white), tanker 200 (Takehara Chemical Co., trade name, calcium carbonate) 20 parts, Hospitan C (Showa Denko Co., trade name, magnesium phosphate of ascorbic acid) 5 parts and deionized water are added, and dispersed for 60 minutes using a desktop sand mill. Thus, a pigment paste (E) having a solid content of 30% by weight for an aqueous coating composition was obtained.

Preparation Example of Pigment Paste (F) Pigment paste (F) was obtained in the same manner as in Preparation Example of pigment paste (E) except that magnesium phosphate of ascorbic acid was not blended.

[0044]

[Table 1]

Production Example of Emulsion for Water-based Paint In a reaction vessel, 140 parts of deionized water, "Newcol-707SF"
(Manufactured by Nippon Emulsifier, surfactant, solid content 30%) 2.5
Parts, and a monomer mixture (methyl methacrylate 55
Part, styrene 8 parts, n-butyl acrylate 9 parts, 2-
(1 part of 5 parts of hydroxyethyl acrylate, 2 parts of 1,6-hexanediol diacrylate and 1 part of methacrylic acid) were added, and the mixture was stirred and mixed in a nitrogen stream.
3 parts of ammonium persulfate were added.

Then, the mixture was heated to 80 ° C., and the remaining 79 parts of the monomer mixture, 2.5 parts of “Newcol-707SF”,
A pre-emulsion consisting of 4 parts of 3% ammonium persulfate and 42 parts of deionized water was added to the reaction vessel over 4 hours using a metering pump, and the mixture was aged for 1 hour after completion of the addition.

Further, at 80 ° C., a monomer mixture (5 parts of methyl methacrylate, 7 parts of n-butyl acrylate, 5 parts of 2-ethylhexyl acrylate, 3 parts of methacrylic acid and 0.5 part of “Newcol-707SF”) 20. 5 parts and 4 parts of 3% ammonium persulfate were simultaneously added dropwise over 1.5 hours, aged for 1 hour after the addition was completed, deionized water was added, and the pH was adjusted to 7.5 with dimethylethanolamine. An emulsion for a water-based paint having a diameter of about 0.1 μm and a solid content of 35% was obtained.

Example 1 3 parts of pigment paste (A) in a stirring and mixing vessel, OH content / N
Sumidur N3300 so that CO amount = 1/1
(Trade name of hexamethylene diisocyanate, manufactured by Sumitomo Bayer Urethane Co., Ltd.) 17 parts of organic solvent type paint N having a solid content of 32% by weight was added and stirred with a disper.
o. 1 was obtained.

Examples 2 to 4 The same procedure as in Example 1 was applied to each of the pigment paste (B) and the pigment paste (C). 2, paint No. Example 3 and Example 4 in which the pigment paste (E) and the emulsion were diluted with deionized water.
Water-based paint No. 4 was obtained.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the pigment paste (D) was used and the paint No. of Comparative Example 1 was used. 5 was obtained.

Comparative Example 2 The same procedure as in Example 4 was carried out except that the pigment paste (F) was used and the paint No. of Comparative Example 2 was used. 6 was obtained.

The paint Nos. In Examples 1 to 4 and Comparative Examples 1 and 2 were used. 1 to No. Table 2 shows the content of No. 6.

[0053]

[Table 2] Preparation of coating test A cold-rolled dull steel sheet (0.8 x 150 x 70 mm) chemically converted with Palbond # 3020 (trade name, zinc phosphate treating agent, manufactured by Nippon Parkerizing Co., Ltd.) was obtained in Examples and Comparative Examples. Paint composition No. 1 to No. No. 6 was applied by spray coating so that the dry film thickness became 20 μm. Baking and drying is performed at a surface temperature of 100 ° C.
This was performed using an electric hot air drying oven for 30 minutes. Table 3 shows the results of the coating film performance test.

[0054]

[Table 3]

(Note 1) Salt spray resistance: baking and drying temperature-time Each coated plate obtained at 100 ° C. for 30 minutes was subjected to a cross-cut flaw in a coating film with a cutter knife so as to reach a base material. A salt water spray test was conducted for 240 hours in accordance with JISZ-2371, and evaluated according to the following criteria based on the scratches from the cut portion, blister width, and the coating state (blister) of the general portion. ：: No blistering when the maximum width of rust and blisters was less than 2 mm (one side) from the cut portion. △: The maximum width of rust and blisters is 2 mm or more from the cut part, 3
mm (one side) and blisters are observed on part of the coated surface. ×: The maximum width of rust and blisters is 3 mm or more from the cut portion and blisters are observed on the entire coated surface.

(Note 2) Salt water immersion resistance: baking and drying temperature-time 100 ° C., each coated plate obtained in 30 minutes,
A cross-cut wound was made on the coating film with a cutter knife so as to reach the substrate, and this was subjected to a saltwater immersion test at 50 ° C. for 240 hours, and the damage from the cut portion, blister width, and the coated surface condition (blister) of the general portion were determined. Evaluation was made according to the following criteria. ○: The maximum width of rust and blisters is 1.5 mm on one side from the cut part
Above, less than 2.5 mm on one side. △: The maximum width of rust and blisters is 2.5 mm on one side from the cut part
Above, less than 3.5 mm. ×: The maximum width of rust and blisters is 3.5 mm on one side from the cut part
that's all.

(Note 3) Secondary water resistance: baking temperature 8
Each coated plate obtained at 0 ° C. for 30 minutes is immersed in warm water at 40 ° C. for 168 hours, and a 2 mm square gobang cut is made. Then, cellotape (registered trademark) is peeled off to evaluate the remaining coating film. .

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J038 BA021 CA041 CD021 CD091 CF021 CG001 DA111 DB001 DD001 DG001 JC24 KA05 NA03 NA26 NA27 PC02

Claims (3)

[Claims] 1. A coating composition containing a metal phosphate of ascorbic acid represented by the following structural formula (1). Embedded image Structural formula (1) (M represents a metal having 1 to 3 valences, and n represents an integer of 1 to 3) 2. The coating composition according to claim 1, wherein in the metal phosphate of ascorbic acid represented by the structural formula (1), M is Mg of magnesium ascorbic acid. 3. The coating composition according to claim 1, wherein in the metal phosphate of ascorbic acid represented by the structural formula (1), M is sodium phosphate of ascorbic acid of Na.