JPH1192692A - Rust-preventive coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject non-pollution type composition having an excellent rust-preventing performance by including hydrocalumite into a rust- preventing coating vehicle containing a white inorganic pigment. SOLUTION: This rust-preventing coating containing a white inorganic pigment (e.g. an extender pigment such as clay, a white pigment such as titanium dioxide, a rust-preventing pigment such as magnesium phosphite) further contains a hydrocalumite of the formula: (3-4)CaO.Al2 O3 .CaX2/m .nH2 O [X is a monovalent or divalent anion; (m) is the valency of an anion; ; (n) is <=20]. The anion X in the hydrocalumite is preferably NO3 <-> or NO2 <-> . The hydrocalumite is preferably obtained e.g. by a method comprising crystallizing raw materials comprising sodium aluminate, a soluble calcium salt and/or an alkali metal salt, and slaked lime. The rust-preventing coating composition preferably comprises 100 pts.wt. of a coating vehicle, 5-40 pts.wt. of an inorganic pigment, and 0.1-10 pts.wt. of hydrocalumite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pollution-free rust-preventive paint composition, and more particularly to a rust-preventive paint composition containing a pollution-free inorganic pigment and hydrocalumite.

[0002]

2. Description of the Related Art As rust preventive pigments, lead salts such as lead red, lead suboxide, cyanamide lead, calcium lead oxide, basic lead sulfate, basic zinc chromate, tetrabasic zinc chromate,
Chromate-based materials such as barium chromate, calcium chromate, and strontium chromate have been mainly used. However, although these rust-preventive pigments exhibit excellent rust-preventing performance against metals, their use has been gradually restricted due to health problems and environmental conservation problems.

[0003] Non-polluting rust-preventive pigments that can be used in place of these include phosphates such as zinc phosphate, calcium magnesium phosphate, titanium phosphate and silica phosphate, condensed phosphates such as aluminum tripolyphosphate, and phosphorous acid. Non-polluting rust preventive pigments such as zinc, calcium phosphite, strontium phosphite, aluminum phosphite, etc., and zinc molybdate, calcium molybdate, barium borate, zinc borate, etc. have been developed. Department has been commercialized.

[0004] However, there is still a demand for a pigment having a stronger rust-preventing power comparable to a chromium salt-based or lead salt-based pigment, for example, a basic zinc phosphite (JP-A-50-50).
No. 297), a zinc zinc phosphite complex (JP-A-58-194725), a rust-preventive pigment formed by the reaction product of zinc phosphite and zinc white (JP-A-57-10986).
2), zinc potassium phosphite based rust preventive pigments (JP-A-58-84109, JP-A-59-20466) and zinc calcium phosphite (JP-A-3-111).
No. 457), a plate-like calcium phosphite (Japanese Unexamined Patent Application Publication No.
JP-A-285808), a rust-preventive pigment obtained by chemically modifying the surface of a condensed phosphate and a zinc compound and / or a borate compound (JP-A-2-151664), chelating to zinc phosphite and / or calcium phosphite Rust-preventive pigment containing an organic phosphorus compound having a function (Japanese Patent Laid-Open No. 6-934)
No. 78), a rust-preventive pigment obtained by reacting zinc oxide with an organic phosphonic acid having a chelating ability, and a rust preventive comprising a mixture of the rust-preventive pigment and a phosphate-based or phosphite-based white rust-proof pigment. Non-polluting white rust preventive pigments such as pigments (JP-A-6-122986) have been proposed.

Further, from the viewpoint of the paint, for example, a rust-preventive paint composition containing hydrotalcite (Japanese Unexamined Patent Publication No.
-70463, JP-A-61-66767 and JP-A-5-306124) and rust preventive pigments and sodium nitrite, ammonium nitrite, calcium nitrite, sodium sulfite, sodium benzoate, benzoic acid in water-based paints. An aqueous coating composition containing a corrosion inhibitor selected from ammonium (JP-A-8-73776) and the like have been proposed.

[0006]

However, although these rust preventive paints can be expected to have a certain effect, they are particularly non-polluting paints for electrodeposition paints used for painting automobiles and electric appliances and for PCM paints. In spite of the urgent need, a rust preventive paint exhibiting excellent rust preventive performance has not yet been put to practical use. Also, due to environmental issues,
There is a demand for conversion to a water-based paint instead of the conventional solvent-based paint, and development of a pollution-free rust-proof paint exhibiting more rust-proof performance is desired. In view of the above problems, the present inventors have conducted intensive studies on a pollution-free rust-preventive paint composition, and as a result, a paint containing hydrocalumite in a paint vehicle exhibits excellent rust-preventive performance. And found that the present invention was completed. That is, an object of the present invention is to provide a pollution-free rust preventive paint composition having excellent rust preventive performance.

[0007]

The rust-preventive paint composition to be provided by the present invention is a rust-preventive paint containing a white inorganic pigment.

Embedded image (3-4) CaO · Al ₂ O ₃ .CaX _{2 / m} · nH ₂ O (1) (wherein, X is a monovalent or divalent anion, and m is a valency of the anion. And n represents 20 or less.) Is a structural feature.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail. The rust-preventive coating composition according to the present invention is constituted by adding hydrocalumite to a coating vehicle containing a white inorganic pigment. The paint vehicle refers to a liquid component other than a pigment component in a paint in a liquid state. Therefore, although it is mainly a resin for forming a coating film, the whole of oily or aqueous liquid components including auxiliary agents such as diluents, oils such as varnish, viscosity modifiers, dispersants, desiccants, etc. Means

Examples of the white inorganic pigment include white extenders such as clay, calcium carbonate, barium sulfate and talc, white pigments such as titanium oxide, zinc oxide and zinc silicate, and rust preventive pigments.

As rust preventive pigments, Mg, Ca, Ba, S
an oxymetal salt of phosphorus selected from one or more of r, Zn or Al, a metal salt of molybdate, a metal salt of phosphomolybdate, a metal salt of boric acid, a metal salt of borosilicate, a metal salt of phosphosilicate, chromic acid Salts, plumbates, composite oxides of metals and the like can be mentioned, but they have a sufficient effect on rust-preventive pigments such as chromium-based and lead-based pigments, but are not preferred due to environmental problems.

The oxymetal salts of phosphorus include, for example, metal phosphites, metal phosphates and / or metal polyphosphates, and the metal phosphites include, for example, magnesium phosphite, calcium phosphite, Barium phosphite,
Strontium phosphite, zinc phosphite, aluminum phosphite, zinc calcium phosphite, zinc potassium phosphite and the like can be mentioned. As the phosphate, for example, magnesium phosphate, calcium phosphate, barium phosphate,
Strontium phosphate, zinc phosphate, aluminum phosphate, zinc magnesium phosphate, zinc calcium phosphate,
Examples include potassium zinc phosphate, calcium polyphosphate, magnesium polyphosphate, zinc polyphosphate, and aluminum polyphosphate.

Examples of the molybdate metal salt include zinc molybdate, calcium molybdate, barium molybdate, aluminum molybdate, magnesium molybdate, strontium molybdate, zinc calcium molybdate, zinc potassium molybdate, and the like.

Examples of the phosphomolybdate include zinc molybdate, calcium molybdate, barium molybdate, aluminum molybdate, magnesium molybdate, strontium molybdate, and potassium potassium molybdate.

Examples of the borate include zinc borate, calcium borate, barium borate, aluminum borate, magnesium borate, strontium borate, zinc calcium borate, zinc potassium borate and the like.

Examples of the borosilicate include zinc borosilicate, calcium borosilicate, barium borosilicate, aluminum borosilicate, magnesium borosilicate, strontium borosilicate, zinc potassium borosilicate, zinc calcium strontium borosilicate and zinc strontium calcium borosilicate And the like.

Examples of the phosphosilicate include zinc phosphosilicate, calcium phosphosilicate, barium phosphosilicate, aluminum phosphosilicate, magnesium phosphosilicate, strontium phosphosilicate, zinc potassium phosphosilicate, zinc calcium phosphosilicate, and zinc strontium calcium phosphosilicate. Is mentioned.

As the metal composite oxide, ZnO, Ca
Two or more kinds of composite oxides selected from O or MgO are mentioned.

These compounds may be either normal salts or basic salts, and may be hydrates or anhydrides. These inorganic pigments may be used alone or in combination.
Used in more than species.

These white inorganic pigments may be, if desired, an organic phosphoric acid compound selected from acidic phosphoric acid esters and / or phosphonic acids having chelating ability, or derivatives thereof, and white insoluble fine metal oxides. , Hydrated oxide,
Those surface-treated with silica, metal silicate, or the like may be used.

Examples of the acidic phosphate ester include methyl acid phosphate, dimethyl acid phosphate, ethyl acid phosphate, diethyl acid phosphate, methyl ethyl acid phosphate,
Or iso-propyl acid phosphate, positive or iso-dipropyl acid phosphate, methyl butyl acid phosphate, ethyl butyl acid phosphate, propyl butyl acid phosphate, positive or iso-octyl acid phosphate, positive or iso-dioctyl acid phosphate, positive -Decyl acid phosphate, positive-didecyl acid phosphate, positive-lauryl acid phosphate, positive-dilauryl acid phosphate, positive- or iso-cesyl acid phosphate, positive- or iso-disesyl acid phosphate, positive-stearyl acid phosphate,
Positive or iso-distearyl acid phosphate,
Allyl acid phosphate, diallyl acid phosphate and the like, and Mg, Ca, S
One or more metal salts selected from r, Ba, Zn or Al, ammonium salts, and the like. Examples of the phosphonic acid compound having chelating ability include aminoalkylenephosphonic acid, ethylenediaminetetraalkylenephosphonic acid, alkylmethane-1-hydroxy-1,
Representative compounds include 1-diphosphonic acid and 2-hydroxyphosphonoacetic acid. Among them, examples of the aminoalkylenephosphonic acid include nitrilotristyrenephosphonic acid, nitrilotrisporopylenephosphonic acid, nitrilodiethylmethylenephosphonic acid, and nitripropylpropylbismethylenephosphonic acid. Examples of the ethylenediaminetetraalkylenephosphonic acid include ethylenediaminetetramethylenephosphonic acid, ethylenediaminetetraethylenephosphonic acid, and ethylenediaminetetrapropylenephosphonic acid. Examples of the alkylene-1-hydroxy-1,1-diphosphonic acid include methane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, and propane-1-hydroxy-1,1-diphosphonic acid. , Sr, B
One, two or more metal salts selected from a, Zn or Al may be used, but are not limited to these compounds.

In the present invention, the above-mentioned acidic phosphoric acid ester and a compound of phosphonic acid having a chelating ability may be used alone or in combination of two or more. The amount of the acidic phosphoric acid ester and / or the phosphonic acid having chelating ability with respect to the inorganic pigment is not uniform depending on the physical properties and type of the compound used, but is usually 0.1 to 30% by weight.
Preferably, it is 1 to 10% by weight.

Hydrocalumite has the general formula (1)
In the formula, X is a monovalent or divalent anion, m represents the valence of the anion, and n represents 20 or less. Examples of the type of X include OH ⁻ , CO ₃ ⁻ , SO ₄ ²⁻ , MO ₄ ²⁻ , and Cr
O ₄ ²⁻ , WO ₄ ²⁻ , NO ₃ ⁻ and NO ₂ ^{− and the} like can be mentioned. In the present invention, NO ₃ ⁻ and NO ₂ ⁻ are particularly preferable.
Due to its properties, the anion X is not occupied by one kind alone, and is often composed of a composite anion. The particle size of the hydrocalumite is not particularly limited, but the smaller the particle size, the more preferable in terms of paint dispersibility. A method for producing such hydrocalumite may be a known production method. For example, a method of crystallizing using a raw material comprising sodium aluminate, a soluble calcium salt and / or an alkali metal salt, and slaked lime ( JP-A-7-33430
JP), or a CaO-Al ₂ O ₃ compound, and a soluble calcium salt and / or slaked lime are reacted in the liquid, then the method of crystallizing (JP-A-7-33431)
What is obtained by is preferably used. In addition, the hydrocalumite may be further subjected to a surface treatment with a higher fatty acid or a derivative thereof, a surfactant, a silane coupling agent or the like for the purpose of improving dispersibility as required.

The mixing ratio of these two components is 0.3 to 50 parts by weight of an inorganic pigment with respect to 100 parts by weight of a paint vehicle.
Preferably 5 to 40 parts by weight and hydrocalumite 0.1.
It is 0.5 to 30 parts by weight, preferably 0.1 to 10 parts by weight. The reason is that the blending ratio of hydrocalumite is 0.1%.
If the amount is less than 05 parts by weight, a sufficient rust-preventing effect tends to be hardly obtained, and if the amount is more than 30 parts by weight, the rust-preventing effect is saturated and is not practical.

Examples of the coating resin include phenol resin, alkyd resin, melamine resin, guanazine resin, vinyl resin, epoxy resin, polyamine resin, acrylic resin, polybutadiene resin, polyester resin, urethane resin, silicon resin, and fluorine-containing resin. These may be a mixed system or a modified resin, if necessary. As the diluent, water, alcohols, ketones, benzenes, aromatic hydrocarbons such as toluene and xylene, liquefied paraffins, and aliphatic hydrocarbons such as mineral spirits are generally used in paints. Solvents can be applied.

As other components, various paint additives such as a coloring agent, a plasticizer, a curing agent, a bulking agent, a filler, an antioxidant, a thickener, and a surfactant are appropriately used in combination. Can be.

The method for preparing the rust preventive coating of the present invention may be a conventional method. For example, the resin for coating, the inorganic pigment, the diluent and the additive are adjusted so as to have a desired composition. After that, a powdery hydrocalumite may be added to the paint vehicle to perform a uniform paint treatment. As a method of forming a paint at this time, a kneading treatment is performed using a mixing device such as a bead mill, a ball mill, a sand glizer, a roll mill or the like so that hydrocalumite is sufficiently dispersed in the paint vehicle.

The rust preventive paint according to the present invention can be used for brush or roller coating, spray coating, electrostatic coating, roll coater, curtain flow coater, dipping coating, electrodeposition coating and the like.

[0028]

The rust preventive coating composition according to the present invention is characterized in that in a rust preventive paint containing a non-polluting white inorganic pigment, hydrocalumite is contained in the paint vehicle. The strong rust-preventing mechanism of the rust-preventive coating composition of the present invention is complicated and has not been elucidated yet. It is considered that nitric acid-type hydrocalumite exerts strong rust prevention performance in combination with the passivating action of nitrate ions or nitrite ions with iron ions.

[0029]

The present invention will be described in detail below, but the present invention is not limited to these. <Synthesis of nitrite-type hydrocalumite> Na ₂ O: 19
Weight%, Al ₂ O ₃ : 20 weight% sodium aluminate 1
Water was added to 0 kg to make 100 kg (solution a). Water was added to 4.35 kg of slaked lime and 2.94 kg of calcium nitrite monohydrate to make 100 kg (solution b). Then, the solution a was added to the solution a at room temperature by an injection pump over about 1 hour, and a gel-like precipitate was formed. After the addition was completed, the slurry was heated to 60 ° C. and crystallized at normal pressure for 4 hours. The obtained precipitate was filtered and washed by a conventional method, dried, and pulverized to obtain 12 kg of nitrite-type hydrocalumite having an average particle size of 22.1 μm.

<Synthesis of nitric acid type hydrocalumite>
₂ O: 19 wt%, Al ₂ O _3: 20 wt% of sodium aluminate 10kg and mixed with water to prepare 100 kg (a
liquid). 4.35 kg of slaked lime and 3.22 k of calcium nitrate
g was added with water to make 100 kg (solution b). Then, a
When solution b was added to the solution at room temperature over about 1 hour by using an injection pump, a gel-like precipitate was formed. After the addition,
This slurry was heated to 60 ° C. and crystallized at normal pressure for 4 hours. The obtained precipitate was filtered and washed by a conventional method, dried, and pulverized to obtain 12.3 kg of nitric acid type hydrocalmite having an average particle size of 22.0 μm.

Examples 1 to 5 100 parts by weight of a commercially available epoxy resin (manufactured by Yuka Shell Epoxy; Epicoat 100X75; nonvolatile content: 75%), 20 parts by weight of calcium phosphite, 10 parts by weight of calcium carbonate, 5 parts by weight of titanium oxide, 160 parts by weight of glass beads and xylene / methyl ethyl ketone (1/1: v / v) 4
After charging 2 parts by weight and dispersing with a sand grinder at a stirring speed of 2500 revolutions / minute for 2 hours, the nitrite-type hydrocalumite prepared above was added to 0.5, 1.0, 5.0,
10, 30 parts by weight were charged and dispersed again with a sand grinder to prepare a main ingredient. Next, as a curing agent, tomide 410-N (manufactured by Fuji Kasei Kogyo;
%) Of 96 parts by weight, and further 20 parts by weight of xylene / isobutanol (7/3; v / v) were added and sufficiently dispersed in the main agent, and then a rust preventive paint was prepared.

Comparative Example 1 Examples 1 to 5 except that no hydrocalumite was added.
A dry epoxy resin was prepared under the same operating conditions as described above.

Examples 6 to 14 100 parts by weight of a commercially available thermosetting acrylic paint resin (Almatex 782-5 manufactured by Mitsui Toatsu Chemicals), 20 parts by weight of an inorganic pigment of the type shown in Table 1, and 10 parts by weight of calcium carbonate Parts, 5 parts by weight of titanium oxide and xylene / toluene (1/1)
1: v / v) and 2,500 with a sand grinder
After dispersing for 2 hours at a stirring speed of rotation / min, 1.0 part by weight of the nitrite-type hydrocalumite or nitrate-type hydrocalumite prepared above was charged, and further, xylene / toluene (1/1: v / v ) Was charged in an amount of 20 parts by weight and dispersed again with a sand grinder to prepare a rust preventive paint.

Comparative Examples 2 to 10 Rust-preventive paints were prepared under the same operating conditions as in Examples 6 to 14 except that no hydrocalumite was added.

[0035]

[Table 1]

Example 15 60 parts of water and 1.0 part of hydroxyethylcellulose (Natrosol 250MR manufactured by Hercules) were added, and while stirring with a disper, 0.2 part of ammonia and 1. dispersant were added.
0 parts and 0.2 parts of an antifoaming agent, and 40 parts of calcium phosphite and 100 parts by weight of glass beads were added.
After stirring at rpm for 30 minutes to uniformly disperse the pigment, the glass beads were removed (solution a). Nitrite-type hydrocalumite (10 parts by weight) was added to water (90 parts by weight) and dissolved by stirring (solution b). 1.3 parts by weight of liquid a and 0.5 part by weight of liquid b were added to 100 parts by weight of a commercially available water-based emulsion paint white (Glossy Emulsion GP manufactured by Shinto Paint Co., Ltd.) and mixed to prepare a rust preventive paint.

Comparative Example 11 A rust preventive paint was prepared under the same conditions as in Example 15 except that no hydrocalumite was added.

<Evaluation of Rust Prevention Performance> (1) Preparation of Painted Steel Sheet The rust prevention paints prepared in Examples 1 to 15 and Comparative Examples 1 to 11 were manufactured by Nippon Test Panel of 70 × 150 × 0.7 mm, S
It was applied to a PCC-SD steel plate by a bar coder so as to have a dry film thickness of 30 to 35 μm, and was dried for one week in a constant temperature / humidity chamber at 25 ° C. and 60% humidity to obtain a paint steel plate. (2) Rust prevention test The painted steel plate prepared in (1) was masked on its back and end surfaces with 3M Scotch brand tape, cross-cut, and set on a salt spray tester to perform a rust prevention test. (3) Evaluation of Rust Prevention Performance The results of the salt spray test for 400 hours were evaluated by the following five-step evaluation method, the rust prevention effect was determined, and the results were shown in Table 2.
It was shown to. Evaluation 5: No rust was generated except for the cross cut portion, and there was no blister. Evaluation 4: Rust is generated within 2 mm on one side from the cross cut portion, and there is no blister. Evaluation 3: Rust and partial blisters occurred within 6 mm on one side from the cross cut portion. Evaluation 2: Rust and partial rust occurred within 12 mm on one side from the cross cut portion. Evaluation 1: Rust and blisters occurred on the entire steel sheet.

[0039]

[Table 2]

[0040]

As described above, the rust-preventive coating composition of the present invention contains hydrocalumite, which is an inorganic anion exchanger, in a coating vehicle and exhibits excellent pollution-free and excellent rust-preventive performance. The value of use as a paint for preventing rust of metal is extremely large.

Claims (3)

[Claims] 1. A rust-preventive paint containing inorganic pigments white, the following general formula ## STR1 ## _{(3~4) CaO · Al 2 O} 3 · CaX 2 / m · nH 2 O (1) ( Formula Wherein X represents a monovalent or divalent anion, m represents the valence of the anion, and n represents 20 or less.) Hydrocormite represented by the formula: Stuff. Wherein X is NO ₂ ^- or NO ₃ ^- at least one selected from a claim 1 anticorrosive coating composition. 3. An inorganic pigment of 0.3 to 50 parts by weight and hydrocalumite of 0.1 part by weight per 100 parts by weight of a paint vehicle.
The rust-preventive coating composition according to claim 1, which contains 0.5 to 30 parts by weight.