JPH1149978A - Rustproof pigment composition and rustproof coating material containing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pigment which does not cause pollution and has excellent rustproof properties and a coating material contg. the same by using, as the main ingredients, a rustproof pigment and zinc oxide modified with a metal nitrite. SOLUTION: Industrially available zinc oxide can be used without any limitation; however, one specified by JIS K-5102 is pref. The rustproof pigment is an oxo-acid salt of phosphorus, a molybdate, a borate, or the like of at least one metal selected from among Mg, Ca, Ba, Sr, Zn, and Al. The oxo-acid salt of phosphorus is a phosphite or a phosphate and/or a polyphosphate; zinc molybdate and calcium molybdate are examples of the metal molybdate; and zinc borate, calcium borate, etc., are listed as the borate. The modified zinc oxide is prepd. by bonding both the ingredients to zinc oxide particles with a metal nitrite by a wet or dry process. Calcium nitrite is pref. as the metal nitrite and is used in an amt. of 0.1-10 wt.% of zinc oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-polluting white rust preventive pigment useful for preventing metal corrosion and a rust preventive paint containing the same.

[0002]

2. Description of the Related Art As rust preventive pigments, lead salts such as lead red, lead oxide, cyanamide lead, calcium lead acid, basic lead sulfate, basic zinc potassium chromate, tetrabasic zinc chromate, chromate Chromate-based materials such as barium, 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. Phosphite-based pigments such as zinc, calcium phosphite, strontium phosphite, and aluminum phosphite, and non-polluting and non-toxic rust-proofing pigments such as zinc molybdate, calcium molybdate, barium borate, zinc borate, etc. Some have been put into practical use. However, since they are not comparable to chromium or lead salt pigments, pigments having a stronger rust-preventive effect are demanded. For example, basic zinc phosphite (JP-A-50-50297), hydroxy Zinc phosphite complex (JP-A-58-194725), rust-preventive pigments formed by the reaction product of zinc phosphite and zinc white (JP-A-57-109862), zinc zinc phosphite-based Rust preventive pigments (JP-A-58-84109, JP-A-59-20466), zinc calcium phosphite (JP-A-3-111457), plate-like calcium phosphite (JP-A-3-285808) JP, JP-A-2-151664, zinc phosphate and / or zinc phosphite, wherein the surfaces of a condensed phosphate and a zinc compound and / or a borate compound are chemically modified. Rust preventive pigment containing calcium phosphate containing an organic phosphorus compound having chelating ability (JP-A-6-93478), rust preventive pigment prepared by reacting zinc oxide with an organic phosphonic acid having chelating ability, and this rust preventive pigment Rust-preventive pigments consisting of rust- and phosphite-based white rust-preventive pigments (JP-A-6-12298)
No. 6 gazette) and the like.

[0004]

Although these non-polluting rust preventive pigments can be expected to have a certain effect, they are particularly non-polluting for electrodeposition paints and PCM paints used for painting automobiles and electric appliances. Despite the urgent need for a type of rust preventive pigments, those that are comparable to the rust preventive function of lead salts and chromates have not been put to practical use. On the other hand, from the viewpoint of paints containing these rust-preventive pigments, conversion to water-based paints has been required in place of conventional solvent-based paints due to environmental problems. The development of pollution-type rust preventive paints is desired.

In view of the above facts, the present inventors have conducted intensive studies on non-polluting rust preventive pigments, and as a result, have found that zinc oxide modified with metal nitrite and rust preventive pigments as main components. The inventor has found that the rust pigment composition has excellent rust-preventing power and shows stable pigment properties, and has completed the present invention. That is, an object of the present invention is to provide a rust preventive pigment having excellent rust preventive performance without pollution and a rust preventive paint containing the same.

[0006]

The rust-preventive pigment composition provided by the present invention is characterized by comprising zinc oxide modified with a metal nitrite and a rust-preventive pigment as main components. . Further, a rust preventive paint provided by the present invention is characterized by containing the above rust preventive pigment composition in constitution.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The zinc oxide used in the present invention is not particularly limited as long as it is industrially available, but those specified in JIS K-5102 are preferable. As the rust preventive pigment, M
1 selected from g, Ca, Ba, Sr, Zn or Al
One or more metal phosphorus oxyacid salts, molybdates, phosphomolybdates, borates, borosilicates,
Phosphosilicate and the like can be mentioned. Examples of the metal oxyacid salts of phosphorus include phosphites, phosphates and / or polyphosphates, and examples of the phosphites include magnesium phosphite, calcium phosphite, barium phosphite, and phosphite. Strontium phosphate, 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, zinc potassium phosphate, zinc potassium phosphate, calcium polyphosphate, magnesium polyphosphate, polyphosphate Zinc acid and aluminum polyphosphate.

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

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 calcium zinc strontium phosphosilicate. Is mentioned. These compounds may be either normal salts or basic salts, or may be either water-containing or anhydrous, and one or more of these rust-preventive pigments may be used. .

In the present invention, the modified zinc oxide is one that has been surface-treated with a metal nitrite. That is, as described later, both components are chemically or physically bonded to zinc oxide particles in a wet or dry manner. Examples of the metal nitrite include one or two of sodium nitrite, potassium nitrite, lithium nitrite, magnesium nitrite, calcium nitrite, barium nitrite, strontium nitrite, zinc nitrite, and aluminum nitrite.
Species or more, among which calcium nitrite is preferred. These nitrites may be either water-containing or anhydrous.

The amount of the metal nitrite is 0.1 to 10% by weight, preferably 1 to 2% by weight, based on zinc oxide. When the amount is less than 0.1% by weight, the rust-preventing performance is not exhibited. And the water resistance and paint stability tend to be poor, and the raw materials themselves are expensive, which is not economical. The mixing ratio of the modified zinc oxide and the rust preventive pigment is
The weight ratio ranges from 1:50 to 50: 1.

To obtain the modified zinc oxide of the present invention,
Usually performed by a wet method, but is not particularly limited.For example, a colloid mill in which a strong shearing force acts on an aqueous slurry of zinc oxide, a homogenizer, a dispersing apparatus such as a bead mill, and the like, after performing a deagglomeration treatment, A method of adding an aqueous solution of a metal nitrite, a method of adding the above-mentioned aqueous solution of a metal nitrite to zinc oxide powder, and the like can be given. The rust-preventive pigment composition comprising the modified zinc oxide and the rust-preventive pigment of the present invention is a mechanical means in which a strong shear force is applied by a wet method or a dry method so that the composition becomes uniform in the above ratio. It is prepared by The wet method is operated by a device such as a ball mill, a disper mill, a homogenizer, a vibration mill, a sand grind mill, an attritor, and a strong stirrer. On the other hand, in the dry method, devices such as a high-speed mixer, a super mixer, a turbosphere mixer, a Henschel mixer, a Nauta mixer, and a ribbon blender can be used. In addition, these uniform compounding operations are not limited to the illustrated mechanical means. If desired, the particle size may be adjusted by pulverizing with a jet mill or the like.

[0014] The above-mentioned metal nitrite-modified one, and further, a metal oxyacid salt of phosphorus and / or zinc oxide are optionally selected from an acidic phosphate ester and / or a phosphonic acid having a chelating ability or a derivative thereof. Organic phosphoric acid compound, white insoluble fine metal oxide,
Surface treated with hydrated oxide, silica, metal silicate, or the like may be used. Examples of the acidic phosphate include methyl acid phosphate, dimethyl acid phosphate, ethyl acid phosphate, diethyl acid phosphate, methyl ethyl acid phosphate, positive or isopropyl acid phosphate, positive or iso-dipropyl acid phosphate, and 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-cetyl acid phosphate, positive or Seo -
Disesyl acid phosphate, positive-stearyl acid phosphate, positive or iso-distearyl acid phosphate, allyl acid phosphate, diallyl acid phosphate, etc., were selected from Mg, Ca, Sr, Ba, Zn or Al of these compounds. One or more metal salts, ammonium salts and the like can be mentioned.

Examples of the phosphonic acid compound having chelating ability include aminoalkylenephosphonic acid, ethylenediaminetetraalkylenephosphonic acid, alkylmethane-1-hydroxy-1,1-diphosphonic acid and 2-alkylphosphonic acid.
Hydroxyphosphonoacetic acid is a typical compound. 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. Alkylene-1-hydroxy-
Examples of 1,1-diphosphonic acid include methane-1-
Hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, propane-1-hydroxy-1,1-diphosphonic acid and the like; and Mg, Ca, Sr, Ba, It may be one or more metal salts selected from Zn or Al, but is not limited to these compounds.

In the present invention, the above-mentioned acidic phosphoric acid ester and a compound of a 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 a chelating ability to the phosphorus-containing metal salt of phosphite or phosphate is not uniform depending on the physical properties and type of the compound used, but is usually 0.1. -30% by weight, preferably 1-1
0% by weight. The amount of the acidic phosphoric acid ester and / or phosphonic acid having chelating ability with respect to zinc oxide is not particularly limited in its upper limit, but is usually 0.1 to 30% by weight, preferably 1 to 20% by weight. It is. In addition, the rust-preventive pigment composition of the present invention 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 rust preventive paint of the present invention contains zinc oxide modified with a metal nitrite and a rust preventive pigment as main components in a paint vehicle. A paint vehicle is a medium in which a pigment is dispersed. That is, polymer substances such as polymerized oil, natural or synthetic resin, and derivatives of cellulose and rubber, which are coating film forming components, and those obtained by dissolving them in a solvent.

The coating vehicle resin used in the present invention includes, for example, phenol resin, alkyd resin, melamine resin, guanazine resin, vinyl resin, epoxy resin, polyamine resin, acrylic resin, polybutadiene resin, polyester resin, urethane resin, silicon resin, Fluorine-containing resins and the like may be mentioned, and these may be a mixed resin or a modified resin as necessary. Examples of the diluent include solvents generally used in paints, such as water, alcohols, ketones, benzenes, aromatic hydrocarbons such as toluene and xylene, and aliphatic hydrocarbons such as liquefied paraffin. Can be applied. The amount of the rust preventive pigment of the present invention relative to the paint vehicle is usually 0.3 to 30% by weight,
Preferably it is 1 to 20% by weight. If the amount is less than 0.3% by weight, the rust-preventing power is low, and if it is more than 30% by weight, the viscosity of the coating material is high, and favorable coating characteristics cannot be obtained. The rust preventive paint according to the present invention can be used for brush or roller coating, spray coating, electrostatic coating, powder coating, roll coater, curtain flow coater, dipping coating, electrodeposition coating and the like.

[0019]

The white rust-preventive pigment composition comprising zinc oxide modified with a metal nitrite and a rust-preventive pigment according to the present invention has excellent rust-preventing power in addition to no pollution and low toxicity. In addition to the pigment properties, it is excellent in the stability of the paint when it is made into a paint. The strong rust-prevention mechanism of the rust-preventive pigment composition of the present invention is complicated and has not been elucidated yet, but it is presumably a passivation-forming action such as chromic acid by nitrite ion and a base of metal ion derived from nitrite. It is considered that the rust-preventing effect of the zinc oxide and the rust-preventive effect of the rust-preventive pigment itself are combined to exert a strong rust-preventive performance.

[0020]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. (Examples 1 to 10) 100 parts by weight of zinc oxide and 1000 parts of water
A part by weight was added and deagglomerated by a colloid mill. Next, calcium nitrite monohydrate was gradually added in the amount shown in Table 1, and the mixture was stirred at a temperature of 40 ° C. for 1 hour.
At a flow rate of 30,000 rpm to an atomizer at 30,000 rpm,
The particles were sprayed into an air stream at 220 ° C. and spray-dried to obtain modified zinc oxide powders A, B, C, D and E.

[0021]

[Table 1]

The modified zinc oxide powder obtained above and the rust preventive pigment shown in Table 2 were mixed in a high speed mixer for 200 hours.
The mixture was dry-mixed at 0 rpm for 5 minutes to prepare a rust preventive pigment composition. Comparative Example 1 A rust preventive pigment composition comprising unmodified zinc oxide and the compounds shown in Table 2 was prepared according to Example 1.

[0023]

[Table 2]

<Evaluation of Primary Rust Preventive Performance> 1 g of the rust preventive pigment composition obtained in Examples 1 to 10 and Comparative Examples 1 to 6 was added to 100 ml of tap water, and stirred for 5 minutes with a stirrer at 400 to 500 rpm. It was left still for 5 days and filtered. Then, 5 ml of filtrate was added to the degreased and polished SPCC-SD steel plate.
Were spotted respectively. After spotting the filtrate, the rust prevention performance was evaluated by visual observation of the steel sheet surface over time. The results are shown in Table 3. The symbols in the table indicate the following. A: There is no rust at all. ：: Rust is generated in less than 10% of the entire area. Δ: Rust is generated in 10% or more of the entire area. X: Rust is generated in the entire area.

[0025]

[Table 3]

With respect to the rust preventive pigment compositions obtained in Examples 1 to 10 and Comparative Examples 1 to 6, paint dispersibility and rust preventive performance were evaluated. The results are shown in Table 5. A paint containing no rust preventive pigment was used as a blank sample (Comparative Example 7). (1) Preparation of Rust Preventive Paint A curing agent was added to the main component having the composition shown in Table 4, and an air-dry epoxy resin paint was prepared by a paint conditioner method.

[0027]

[Table 4]

(2) Preparation of Painted Steel Sheet The above rust-preventive paint was applied to a 70 × 150 × 0.7 mm SPCC-SD steel plate having a dry coating thickness of 30 mm.
Apply with a bar coater so that
The coated steel plate was dried for one week in a thermo-hygrostat at 60 ° C. and a humidity of 60% to obtain a coated steel plate. (3) Evaluation of dispersibility of paint The paint prepared in (1) was evaluated for the degree of dispersion of the rust-preventive pigment using a grind gauge according to JIS K5101. Good: Dispersion of 10 μm or less Possible: Dispersion of 10 to 50 μm Impossible: Dispersion of 50 μm or more (4) Rust prevention test The coated steel sheet prepared in (2) was masked on the back and end faces with 3M Scotch brand tape and then cross-cut. And set it in a salt spray tester to perform a rust prevention test.

(5) Evaluation of Rust Prevention Performance The results of the salt spray test for 400 hours were evaluated by the following five-step evaluation method, and the rust prevention effect of the rust preventive pigment was determined. 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 blisters partially occurred within 12 mm on one side from the cross cut portion. Evaluation 1: Rust and blisters occurred on the entire steel sheet.

[0030]

[Table 5]

[0031]

As described above, the rust-preventive pigment composition of the present invention contains zinc oxide modified with a metal nitrite and a non-polluting rust-preventive paint as main components. Demonstrates rust prevention. Therefore, a paint containing the pigment composition is useful as a metal rust preventive pigment and as a rust preventive paint.

Claims (4)

[Claims] 1. A rust preventive pigment composition comprising zinc oxide modified with a metal nitrite and a rust preventive pigment as main components. 2. The rust preventive pigment composition according to claim 1, wherein the modified zinc oxide has been surface-treated with a metal nitrite in a range of 0.1 to 10% by weight. 3. The metal nitrite is Na, K, Li, M
1 selected from g, Ca, Ba, Sr, Zn or Al
The rust-preventive pigment composition according to claim 1 or 2, which is a salt of at least one metal. 4. A rust preventive paint containing the rust preventive pigment composition according to claim 1, 2 or 3.