JP2878722B2 - Aluminum pigment, method for producing the same, and metallic paint containing the pigment - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel aluminum pigment, and more particularly, to water resistance, gas generation resistance and gloss when used as a paint pigment or a printing ink pigment. Pigment or aluminum pigment that has long-term storage stability in pigments and inks, giving a metallic coating / printing surface with excellent adhesion
The present invention also relates to an aluminum pigment having heat resistance stability and storage stability that has not been conventionally used for kneading plastics.

[Prior Art] Conventionally, aluminum pigments have been used for metallic paints, printing inks, kneading plastics and the like for the purpose of obtaining a cosmetic effect emphasizing metallic feeling.

However, when used as a metallic paint, with conventional aluminum pigments, the aluminum pigment reacts with the resin component during storage of the paint to gel and become unusable. In addition, there is a drawback in that the water contained in the paint and the aluminum pigment react with each other to generate hydrogen gas and deform the container. The generation of hydrogen gas is remarkably accelerated by the presence of an acid or alkali component, and furthermore, the amount of hydrogen gas is extremely large in aqueous paints such as water-soluble paints in which a part or most of the solvent is water and aqueous paints such as aqueous emulsions. Left with stability problems. Further, a coating film obtained by coating with a metallic paint is discolored or deteriorates in gloss with time of the paint, so that the use of the metallic paint is limited.

In recent years, metallic coatings have been used in a wide range of applications, and not only high water resistance and gas generation resistance are required, but also metallic coatings with excellent gloss are desired.

Aluminum pigments used for metallic paints are obtained by pulverizing saturated or unsaturated fatty acids such as stearic acid and oleic acid, aliphatic amines or other fatty acid derivatives with a wet ball mill, an attritor or the like as a surface treatment agent. Pigments are inferior in water resistance, gas generation resistance and storage stability, and various processing techniques have been proposed to date to solve these disadvantages. For example,
No. 61-29607 discloses a method of using a phosphoric acid ester of caprolactone for the purpose of suppressing the reaction between a metal powder pigment and water and improving storage stability. For the same purpose, a method using octylphenyl dihydrogen phosphate and a bis (octylphenyl) hydrogen phosphate adduct of cyethylamine, and Japanese Patent Application Laid-Open No. 61-47771,
A method using a reaction product of orthophosphoric acid or a phosphoric acid monoester and an epoxy compound, and further Japanese Patent Application Laid-Open No. 61-291662 discloses a copolymer of styrene-allyl alcohol and p
Although methods using a reaction product of -tert-amylphenol and orthophosphoric acid or phosphorus pentoxide are disclosed, however, the desired improvement effect is insufficient,
The improvement effect was relatively recognized.

On the other hand, Japanese Patent Publication No. 60-8057 discloses an extremely effective method for suppressing the reaction between metal powder and water by using a specific organic phosphate ester. When used in the above, the performance of the obtained coating film, for example, adhesion and gloss were not always sufficient.

Generally, aluminum products manufactured for industrial use, such as aluminum plates and aluminum foil, naturally form an oxide film having good adhesion in the air, and therefore exhibit appropriate corrosion resistance. However, it is known that the oxide film is very thin and has a thickness of only about 0.002 μm (20 °), so that the surface is uneven and it is difficult to maintain complete corrosion resistance. (Metalworking Handbook, page 563, published by Asakura Shoten, 1968, 11th edition) Therefore, such an aluminum pigment having only a natural oxide film cannot maintain sufficient corrosion resistance to water in paint.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention provides excellent water resistance and gas generation resistance by forming a specific uniform and stable oxide film layer on an aluminum pigment surface. An object of the present invention is to provide an aluminum pigment having storage stability, adhesion, and gloss.

[Means for Solving the Problems] The water-resistant aluminum pigment provided by the present invention is an aluminum pigment having an aluminum oxide layer on a surface layer, at least in a range of 200 ° in a depth direction from the surface of the aluminum pigment. , ESCA (Electron Sp
The above problem can be solved by the ratio (B / A) of the peak area A corresponding to metallic aluminum to the peak area B corresponding to aluminum oxide in the Al _2P electronic spectrum by ectroscopy Chemical Analysis) of 1 or more. it can.

Aluminum pigment in the present invention, based on aluminum powder 100 parts by weight, phosphoric acid mono- and / or diester compound 0.05 to 20 parts by weight, water 0.01 to 40 parts by weight, a mixture consisting of an organic solvent 1 to 70 parts by weight, It can be obtained by aging under heating for a suitable period of time sufficient to form a stable oxide film layer.

The phosphoric acid mono- and / or diester compound in the present invention adsorbs on the surface of the aluminum powder, thereby promoting an appropriate oxidation reaction on the surface of the aluminum powder, and oxidizing that can impart stable water resistance and gas generation resistance. This has the effect of forming an aluminum layer. Preferred phosphoric acid mono- and / or diester compounds have, as an ester residue, an alkyl group having 6 to 24 carbon atoms, preferably 12 to 18 carbon atoms, an alkenyl group having 6 to 24 carbon atoms, and preferably 12 to 18 carbon atoms. It has an alkyl group having 1 to 24, preferably 12 to 18 or an aryl group containing one or more alkenyl substituents having 6 to 24, preferably 12 to 18 carbon atoms. And an alkylene oxide having 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms, added in an amount of 0 to 20 mol, preferably 0 to 10 mol.

Further, it may be a mixture of mono- and diesters or a mixture of mono- and / or di-ester compounds of different types of ester residues.

As the alkyl group or alkenyl group, for example, octyl, decyl, tridecyl, lauryl, cetyl, stearyl, oleyl, hexadecyl and the like are preferable. As the aryl group, for example, octylphenyl, nonylphenyl, dodecylphenyl, dinonylphenyl and the like are preferable. As the alkylene oxide, ethylene oxide, propylene oxide and the like are preferable.

Further, as the phosphoric acid mono- and / or diester compound in the present invention, Or a compound structurally equivalent to such a group. The compound containing the above group (1) or (2) in the molecule is derived from a substance containing a functional group reactive with orthophosphoric acid or its monoester compound. For example, a reaction product of orthophosphoric acid or its monoester compound and a compound containing at least one epoxy group, an addition polymer having orthophosphoric acid or its monoester compound and a functional group OH, and / or a monohydric alcohol or Reaction products with a monohydric phenol are exemplified.

These phosphoric acid mono- and / or diester compounds are:
Since it has one or two acidic OH groups and shows acidity in an aqueous medium, it is necessary to use ammonia, dibutylamine, triethylamine, monoethanolamine, diethanolamine, morpholine, sodium hydroxide, potassium hydroxide, and other organic and It can be used after neutralization with an inorganic basic substance.

The method for adding the phosphoric acid mono- and / or diester compound is not particularly limited. In general, a method for producing flake-like aluminum powder is obtained by grinding a raw aluminum atomized powder in an organic solvent in the presence of a grinding aid using a known wet ball mill called an Hall method, an attritor, or the like. . At this time, an aliphatic amine is used as a grinding aid. On the other hand, a mono- and / or diester phosphate compound is added to water, if necessary, for the flaky aluminum powder which has been subjected to a surface treatment with an aliphatic amine.
It can be added later together with the organic solvent.

If necessary, various additives can be used in combination with the aluminum pigment of the present invention. For example, addition of a surfactant for achieving aqueous conversion may be mentioned. The surfactant is not particularly limited, but it is preferable to use a nonionic surfactant from the viewpoint of storage stability. As other additives, known leveling agents, thickeners, coloring pigments and the like can be used.

The phosphoric acid monoester or diester compound used in the present invention is adsorbed on the aluminum powder surface, promotes an excessive oxidation reaction, and forms an aluminum oxide layer capable of imparting stable water resistance and gas generation resistance. Aluminum powder
0.05 to 20 parts by weight, preferably 1 to 10 parts by weight per 100 parts by weight
Used in parts by weight. If the amount is less than 0.05 part by weight, there is no surface protection effect and the oxidation reaction proceeds.If the amount is more than 20 parts by weight, the oxidation reaction is inhibited and the adhesion and gloss of the coating film when used as a metallic paint are remarkably increased. Lower.

The amount of water used in the present invention is aluminum powder 100.
It is 0.01 to 40 parts by weight, preferably 1 to 20 parts by weight based on parts by weight. When the amount is less than 0.01 part by weight, an oxide film having a surface protecting effect is not formed, and when the amount exceeds 40 parts by weight, an oxidation reaction easily proceeds, a stable film is not formed, and aggregation, gas generation and deterioration of the film appearance are caused.

As the organic solvent used in the present invention, a hydrocarbon solvent, an alcohol solvent, a cellosolve solvent, or the like is used. Examples of the hydrocarbon solvent include mineral spirit, solvent naphtha, HAWS, LAWS (Shell Chemical Co., Ltd.)
And other aliphatic or aromatic hydrocarbons. Examples of the alcohol-based solvent include ethanol, butanol, and isopropanol, and examples of the cellosolve-based solvent include ethyl cellosolve, butyl cellosolve, and ethylene glycol. One or more of these solvents may be used as necessary.

The amount of the organic solvent used is suitably from 1 to 70 parts by weight, preferably from 10 to 40 parts by weight, based on 100 parts by weight of the aluminum powder. If the amount is less than 1 part by weight, the water resistance of the aluminum pigment is impaired. If the amount exceeds 70 parts by weight, formation of an oxide film having a surface protection effect is hindered.

The novel aluminum pigment according to the present invention has a ratio of a peak area A corresponding to metallic aluminum to a peak area B corresponding to aluminum oxide in an Al _2P electron spectrum by ESCA at least in a range of 200 ° from a surface layer of the aluminum pigment to a depth direction ( The objective can be achieved when B / A) is 1 or more. When B / A is less than 1, the active metallic aluminum is excessively present in the aluminum pigment, and the surface of the aluminum pigment cannot be said to be a uniform and stable oxide film layer, and has sufficient water resistance and gas generation resistance. I can not get the nature. If B / A is 1 or more,
The higher the value, the more inert the surface of the aluminum pigment and the higher the water resistance. However, on the other hand, an increase in the thickness of the oxide film layer affects the optical characteristics, and particularly degrades the metallic feeling. Therefore, B / A is preferably 100
Or less, more preferably 50 or less, even more preferably 20 or less. Also, when B / A is measured from the surface layer in the depth direction, B / A
If the range of 1 or more is less than 200 °, the oxide film layer is too thin, so that sufficient water resistance and gas generation resistance cannot be obtained.

In the present invention, the range from the surface layer where B / A is 1 or more to the depth direction needs to be at least 200 °. Note that B
The upper limit of the range from the surface layer to the depth direction where / A is 1 or more is
There is no particular limitation. The value can be set arbitrarily according to the optical characteristics desired by the user.

The novel aluminum pigment having a B / A of 1 or more at least in the range of 200 ° from the surface layer of the aluminum pigment in the depth direction to the aluminum pigment according to the present invention is a monophosphate and / or diester phosphate based on 100 parts by weight of aluminum powder. Compound 0.05 to 20 parts by weight, water 0.01 to 40 parts by weight, organic solvent 1 to 70
It is prepared by aging a mixture consisting of parts by weight at a suitable temperature and for a time sufficient to form a stable oxide film. The method of aging is not particularly limited, and examples thereof include aging in a pasting step (mixing process) using a mixer or the like, aging during storage of the obtained paste, and the like. The term "aging" as used herein means that a certain time elapses at a certain temperature for aging.

Aging in the present invention, at least 20 ° C.,
If the temperature is less than 20 ° C. and less than 3 days, which requires at least 3 days or more, a uniform and stable oxide film layer is not formed on the surface of the aluminum pigment, and as a result, the water resistance and gas generation resistance are insufficient. Become. The aging temperature and time work synergistically, shortening the time when the temperature is high,
When the temperature is low, the formation of the desired stable oxide film can be adjusted by increasing the time. The aging temperature is preferably at least 20 ° C or higher, more preferably 35 ° C or higher, and further preferably 50 ° C or higher. Further, the aging time is preferably at least 3 days or more, more preferably 6 days or more, and still more preferably.
10 days or more.

The water resistance test referred to in the present invention refers to the aluminum pigment.
A sample in which 200 ml of ion-exchanged water was added to 20 g (65% of the heating residue) and shaken vigorously to disperse the sample, collected in a 200 ml Erlenmeyer flask, attached to a female pet with a rubber stopper, immersed in a 50 ° C hot water bath, and allowed to stand for 24 hours It is to measure the amount of hydrogen gas generated at the time.

As a result of the water resistance test, the aluminum pigment of the present invention has a hydrogen gas generation amount of 2 ml per 1 g of the aluminum pigment.
Or less, more preferably 1.0 ml or less, and even more preferably 0.5 ml or less. If the amount exceeds 2 ml, hydrogen gas is remarkably generated when a metallic paint or the like is formed or when the paint is stored, and blistering of the paint can easily occurs, which is not preferable.

The aluminum powder used in the present invention will be described in detail. Aluminum flakes or granular powder is obtained by a mechanical method such as a stamp mill method, a dry ball mill method, a wet ball mill method, an attritor method, and a vibrating ball mill method. % By grinding with an auxiliary grinding agent. By using an aliphatic amine as a grinding aid, the effects of the present invention can be remarkably obtained.

The metallic paint using the aluminum pigment of the present invention comprises (a) 0.1 to 100 parts by weight of the aluminum pigment of the present invention, (c) diluent,
(D) Obtained with paint additives.

As the paint resin, any of the paint resins conventionally used in metallic paints can be used.Furthermore, conventional paints having a large amount of functional groups which react with aluminum and easily cause gelation can be used. It can also be used for resins that have not been used in paints. Furthermore, it can also be used for a resin for water-based paint which contains an extremely small amount or no organic solvent which easily reacts with aluminum and easily generates hydrogen gas.

These resins include acrylic resin, alkyd resin, oil-free alkyd resin, vinyl chloride resin, urethane resin, melamine resin, unsaturated polyester resin,
A urea resin, a cellulosic resin, an epoxy resin and the like are mentioned, and these may be used alone or in combination. As the form of the paint, any of a water-based paint such as a solvent paint or a slurry paint, an emulsion paint, and a water-soluble paint can be used.

The aluminum pigment of the present invention is used in an amount of 0.1 to 100 parts by weight based on 100 parts by weight of the coating resin. Especially 1
Preferably it is 50 parts by weight. If this aluminum pigment is less than 0.1% by weight, the metallic luster required as a metallic paint is insufficient, and if it is used in excess of 100 parts by weight, the amount of aluminum pigment in the paint becomes too large and coating workability becomes poor. Not only does it deteriorate, but also the coating film has poor physical properties, which is not practical.

As the diluent, in the case of a solvent-type paint, aromatic hydrocarbons such as elene and xylene, aliphatic hydrocarbons such as hexane, heptane, and octane; alcohols such as ethanol and butanol; esters such as ethyl acetate and butyl acetate; And common organic solvents such as ketones such as methyl ethyl ketone, chlorine compounds such as trichloroethylene, and cellosolves such as ethylene glycol monoethyl ether. These solvents are preferably used in combination of two or more. or,
In the case of water-based paints, water such as ion-exchanged water, alcohols such as ethanol, butanol and isopropanol, cellosolves or carbitols such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and diethylene glycol monobutyl ether, ethylene glycol, propylene glycol, etc. These are commonly used hydrophilic solvents such as polyhydric alcohols, and these water or hydrophilic solvents may be used alone or in combination of two or more.

The composition of the solvent used is: solubility in paint resins, affinity for aluminum pigments, film forming properties,
It is determined in consideration of painting workability and the like.

As additives, pigments, dyes, wetting agents, dispersants, anti-separation agents, leveling agents, slip agents, anti-skinning agents, anti-gelling agents, anti-foaming agents, etc., which are generally used in the paint industry. It is possible to add.

Example Next, an example of the present invention will be described. First, a test method used in the examples will be described.

[Properties of Aluminum Pigment] Water resistance test: Using an experimental apparatus shown in FIG. 1, 20 g of aluminum pigment (65% of the heating residue) was collected in a 200 ml Erlenmeyer flask, 200 ml of ion-exchanged water was added, and sample 4 was vigorously shaken to disperse Sample 4. I do. A female pipette 1 with a rubber stopper 2 is attached, immersed in a constant temperature bath 3 at 50 ° C., and the amount of gas generated after standing for 24 hours is measured.

Storage stability Place aluminum pigment in a 500ml glass container at room temperature.
Investigate the properties after storage for months.

[Properties of paint and coating film] Gas generation resistance test: A water-soluble acrylic melamine resin paint was prepared by the following formulation, and 100 ml of the test paint was placed in a 200 ml Erlenmeyer flask using the experimental apparatus shown in FIG. Measure the amount of gas generated after standing at ℃ for one month.

Test aluminum pigment (heating residue 65%) 13 parts by weight Water-soluble acrylic resin (heating residue 50%) 370 parts by weight Water-soluble melamine resin (heating residue 50%) 100 parts by weight Deionized water 490 parts by weight 973 parts by weight Part Coating Storage Stability 1) Dispersion Stability of Aluminum Pigment The aqueous metallic coating having the above composition is allowed to stand at room temperature for 3 months, and the dispersion stability is evaluated by the crushing cage method described in 4.4 of JIS K5400.

2) Appearance Appearance A paint film applied immediately after the paint formulation and a paint film applied using a paint left at room temperature for 3 months are compared and observed.

B) The color difference ΔE is measured using a 45 ° -0 ° color difference meter.

B) The gloss retention G is measured using a 60 ° specular gloss meter and calculated by the following equation.

Here, G ₀ is the gloss value of the immediately painted coating after coating formulation, G 'is the gloss value of the coating film which was coated with the left paint by 3 months at room temperature.

C) The metallic feeling of the coating film is visually determined. Here, the metallic feeling refers to a characteristic defined by an optical characteristic peculiar to the metallic coating film, in particular, brightness (whiteness), luminance, and optical anisotropy (flop effect).

Adhesion PB-3118 post-cation electrodeposition coated steel sheet [JIS.G.3141 (SPCC-
SB)], adjust the aqueous metallic paint of the above formulation to a Ford cup (# 4) viscosity of 30 to 35 seconds, apply by spraying, preheat at 80 to 90 ° C, and spray the clear paint of the following formulation, 140 Baking was performed at 30 ° C. for 30 minutes to obtain a coating film for evaluating adhesiveness.

Composition of clear paint Solvent-type acrylic resin (heating residue 50%) 370 parts by weight Solvent-type melamine resin (〃50%) 110 parts by weight Xylene 420 parts by weight 900 parts by weight The thickness of the base metallic coating film is 20 to 25 μm,
The thickness of the top clear coating film was 35 to 40 μm.

The adhesion was evaluated by a grid test described in JIS K5400, section 6.15.

ESCA analysis: First, the aluminum pigment is washed with acetone, powdered, and adhered to a sample holder for ESCA using a double-sided tape for measurement.

The analysis of the change in the depth direction from the sample surface is performed while irradiating the sample surface with an Ar ⁺ beam accelerated at 3 kV to scrape off the surface, that is, performing so-called etching. Aluminum foil was used as a standard for comparison of the etching rate. The etching rate depends on the etching conditions (acceleration voltage, degree of vacuum, time), but is about 10 ° / min. The depth at which the surface is scraped off can be calculated from the etching time.

The Al _2P electron spectrum is divided into a metal aluminum peak assigned to a binding energy of 70.7 eV and an aluminum oxide peak assigned to a binding energy of 73.6 eV. By measuring the areas of these peaks every 5 minutes of the etching time, the composition of the metallic aluminum and aluminum oxide in the depth direction from the sample surface can be known.

Here, the ratio B / A of the peak area (A) corresponding to metallic aluminum and the peak area (B) corresponding to aluminum oxide was calculated.

Example 1 A mixture of 10 kg of aluminum atomized powder and 10 kg of mineral spirit containing 5% by weight of stearylamine was pulverized in a ball mill for 8 hours, and then diluted with 20 kg of mineral spirit, transferred to a slurry tank, and filtered with a filter press. I do. The filter press cake thus obtained had a heating residue of 80% by weight and a mineral spirit of 20% by weight, and the sieve residue at 149μ of this aluminum powder was 0.1% or less.

To 100 parts by weight of this filter press cake, 1 part by weight of lauryl phosphate (a one-to-one mixture of monoester and diester), 25 parts by weight of ion-exchanged water, and 3 parts by weight of polyoxyethylene lauryl ether were added, and the mixture was mixed for 30 minutes. Was left at 35 ° C. for 6 days.

After the aging, the mixture is returned to room temperature, and the properties of the aluminum pigment are water resistance, gas generation resistance, ES
The long-term storage stability by CA and long-term storage stability were examined, and further, the properties of the coating film when used in a water-based paint were examined.

Examples 2 to 14, Comparative Examples 1 to 3 With respect to 100 parts by weight of the filter press case (heating residue: 80%) used in Example 1, mono- and diester phosphate compounds and ion-exchanged water shown in Table 1 , An organic solvent, and polyoxyethylene lauryl ether were added and mixed for 30 minutes, and the mixture was left under aging conditions shown in Table 1. The same evaluation as in Example 1 was performed on the obtained aluminum pigment. Table 1 shows the results.

2a to 2c show a sample of Example 5, respectively.
Photoelectron binding energy to the nucleus of the sample of Comparative Example 2 and the comparative standard sample (aluminum foil) (horizontal axis)
And the intensity of photoelectrons (cps / cm: vertical axis). In the depth direction, it is a graph showing the measurement repeated every 5 minutes of the etching time.

Third ratio of the peak area corresponding to the peak area (A) and aluminum oxide corresponding to metallic aluminum on the basis of the graph of FIG. 2 a~c (B), B / A and Ar ⁺ irradiation by the etching time It is a graph which shows a relationship.

[Effects of the Invention] The aluminum pigment of the present invention is a mixture of a specific phosphate compound in a specific composition and aging to form a strong and stable oxide film layer on the aluminum surface. Excellent in water resistance and gas generation resistance, especially in the water resistance test, it shows the performance that the hydrogen gas generation amount is 2 ml or less per 1 g of aluminum pigment, and when it is used for metallic paint containing water-based paint, it has high gloss and adhesion. It exhibits excellent coating performance.

[Brief description of the drawings]

FIG. 1 is an external view of a test apparatus used for a water resistance test and a gas resistance test, and FIGS. 2a to 2c are respectively a sample of Example 5, a sample of Comparative Example 2, and a standard sample for comparison (aluminum). Foil)
FIG. 3 is a graph showing the results of ESCA analysis, FIG. 4 is a graph showing a relationship between a ratio B / A and an etching time by Ar ⁺ irradiation. 1 ... female pipette, 2 ... rubber stopper, 3 ... warm bath, 4 ...
…sample.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-54475 (JP, A) JP-A-55-158202 (JP, A) JP-A-57-61058 (JP, A) JP-A-61-58 296072 (JP, A) JP-A-53-7725 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09C 1/40 C09D 5/38

Claims (4)

(57) [Claims] 1. An aluminum pigment having an aluminum oxide layer on its surface, wherein at least 200 ° in the depth direction from the surface of the aluminum pigment in accordance with ESCA
l An aluminum pigment, wherein the ratio (B / A) of the peak area A corresponding to metallic aluminum to the peak area B corresponding to aluminum oxide in the _2P electron spectrum is 1 or more. 2. A phosphoric acid mono- and / or diester compound, 0.05 to 20 parts by weight, based on 100 parts by weight of aluminum powder.
The aluminum according to claim 1, wherein a mixture comprising 0.01 to 40 parts by weight of water and 1 to 70 parts by weight of an organic solvent is aged under heating for a suitable time period to form a stable oxide film layer. Pigment manufacturing method. 3. A resin for paint (a), a resin for paint (b) 100
0.1 to 100 weight parts by weight, at least in the range of 200 mm in the depth direction from the surface of the aluminum pigment,
An aluminum pigment, wherein a ratio (B / A) of a peak area A corresponding to metallic aluminum to a peak area B corresponding to aluminum oxide in the Al _2P electronic spectrum according to the invention is 1 or more, (c) a diluent And (d) a paint composition comprising a paint additive. 4. The aluminum pigment according to claim 1, wherein an aliphatic amine is used as a grinding aid.