JP2002030255A - Aqueous composition for film treatment and industrial material having formed film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a film having both good fingerprint resistance and good conductivity and also having corrosion resistance by a simple method of applying and drying on the surface of industrial materials, especially metal materials. Provided are an aqueous composition for film treatment capable of forming a film, and an industrial material having a film formed using the composition. SOLUTION: An aqueous composition for coating treatment comprising a smectite-based clay mineral and a complex compound of a divalent or higher valent metal, and an industrial material having a coating formed using the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an aqueous composition for treating a film. More specifically, the present invention relates to an aqueous composition for coating treatment used to coat surfaces of industrial materials such as steel, plated steel, and other industrial materials such as glass, ceramics, and plastics and to impart functionality thereto. The present invention also relates to an industrial material having a film formed on the surface using the composition.

[0002]

2. Description of the Related Art Metallic materials, especially plated steel materials, which are regarded as industrially important among the typical steel materials, usually have a potential lowering with respect to the base material and have a sacrificial anticorrosion action. And a barrier compound layer is formed on the surface to prevent wear of the plating layer itself and protect the base steel material for a long period of time.
Typical examples of the plating layer include zinc, a zinc-containing alloy, an aluminum zinc alloy, and aluminum.As a barrier compound layer on the surface of the plating layer, a chromate treatment for only a short-term anticorrosion action has been known for a long time. However, recently, the negative influence on the human body and the environment is disliked, and the drastic improvement of the corrosion resistance of the plating layer itself has been accompanied by the active introduction of chromium-free. In addition, the use of unpainted coatings, which take advantage of the beautiful appearance of plated steel materials, has also been expanding, and in addition to corrosion resistance, the fingerprint resistance,
A high level of design performance such as stain resistance and colorless appearance has been required. Above all, fingerprint resistance is regarded as a particularly important item for unpainted plated steel materials. Furthermore, these plated steel materials are often used as chassis materials for printed wiring boards in the field of home appliances and the like, and it is necessary to add special functions such as imparting good grounding properties (conductivity).

[0003] With respect to fingerprint resistance, a coating type chromate film agent containing a large amount of colloidal silica has been used for a long time to prevent corrosion, but recently, a resin-based film agent has often been used. However, in order to obtain sufficient anti-fingerprint performance, it is necessary to form a large amount of a film, which causes a problem that the conductivity of the surface is significantly reduced and the film is not suitable as a film for a chassis material. In particular, development of a film that can obtain conductivity while maintaining fingerprint resistance and design properties has been awaited.

[0004]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems of the prior art. That is,
Industrial material, particularly a simple method of applying and drying on the surface of a metal material, having both good fingerprint resistance and good conductivity, and an aqueous composition for coating treatment used to form a coating also having corrosion resistance, And an industrial material having a film formed using the composition.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, an aqueous liquid containing a smectite-based clay mineral and a metal complex compound of a divalent or higher valent metal has been prepared. It has been found that a film having uniformity, high transparency, good fingerprint resistance, good conductivity and good corrosion resistance can be obtained by coating and drying on a plate, and the present invention has been completed. That is, the present invention relates to an aqueous composition for film treatment, comprising a smectite clay mineral and a complex compound of a divalent or higher valent metal. Such a composition contains a smectite clay mineral, a complex compound of a divalent or higher-valent metal, and water, wherein the metal complex compound is dissolved or dispersed in water, and the smectite clay mineral is colloidally dispersed. The present invention also relates to a film treating agent of the type in which a smectite clay mineral and a complex compound of a divalent or higher valent metal are used as separate systems and are mixed immediately before use. The present invention further relates to an industrial material having a film formed on the surface using the composition.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The smectite-based clay mineral used in the aqueous composition for coating treatment of the present invention is a clay mineral having the following general formula (edited by The Clay Society of Japan, "Clay Handbook Second Edition", Gihodo) Published by Publishing Co., Ltd., May 1987
Pp ^{_{8-66): X m (Y 2+}} , Y 3+) 2 ~ 3 Z 4 O 10 (OH) 2 · nH 2 O ( wherein, X is K, Na, 1 / the 2Ca and 1 / 2Mg At least one kind, m is from 0.25 to 0.6, and Y is
²⁺ is at least one of Mg, Fe ²⁺ , Mn ²⁺ , Ni, Zn and Li, and Y ³⁺ is Al, Fe ³⁺ , Mn ³⁺ and C
at least one of r ³⁺ , Z is at least one of Si and Al, and nH ₂ O is interlayer water). In addition,
In (Y ²⁺ , Y ³⁺ ), Y ²⁺ and Y ³⁺ are Y ²⁺ and / or Y
^It means ³⁺ . In the above, X is interlayer, Y is octahedron, Z
Represents a tetrahedral cation. Specific examples of the smectite-based clay mineral used in the present invention include montmorillonite, sauconite, beidellite, hectorite, nontronite, saponite, iron saponite, stevensite and the like.

[0007] Since the particles of the smectite clay mineral are generally small, they have the property of being excellent in forming a thin film. Smectite-based clay minerals are also produced naturally, but can also be obtained as synthetic products.Either of them can be used in the present invention. For the purpose, it is generally desirable to use synthetic products. Among smectite-based clay minerals, hectorite is preferable because of its generally smaller particle size, and there are natural hectorite and synthetic hectorite, but synthetic hectorite having generally smaller particle size is most preferable.

The smectite clay mineral has a layered structure, and each layer of the crystal structure in the layered structure is composed of two-dimensional platelets having a thickness of about 1 nm as primary particles. Some of the magnesium and aluminum atoms present in the platelet unit are isomorphically substituted with low-valent cation atoms, and as a result, the platelet unit is negatively charged. In the dry state, this negative charge is balanced with displaceable cations outside the lattice structure on the plate surface, and in the solid phase these particles are bound together by van der Waals forces to form a bundle of plates. When such a smectite-based clay mineral is dispersed in an aqueous phase, replaceable cations are hydrated and particles swell, and a stable sol is obtained when dispersed using a normal disperser such as a high-speed dissolver. be able to. In the state of being dispersed in the aqueous phase, the surface of the platelet becomes negatively charged, repels each other electrostatically, and becomes a sol finely divided into platelet-shaped primary particles. The aqueous phase dispersion of the smectite-based clay mineral is a two-dimensional platelet having a thickness of about 1 nm, that is, a square or disk-shaped plate, and one side or the diameter of the plate surface is considered to be 20 to 500 nm. The shape of primary particles is about 1 nm thick
A synthetic hectorite which is a disk-shaped particle having a diameter of 20 to 40 nm is commercially available.

Although the aqueous composition for coating treatment of the present invention has good coating uniformity, the following viscosity characteristics of smectite clay minerals are useful as a factor controlling the coatability. When the smectite clay mineral is dispersed in the aqueous phase, the replaceable cation is hydrated as described above, and the particles swell and separate into platelets. In the state of being dispersed in the aqueous phase, the platelets have negative surface charges and the ends have positive charges.
Under the condition that the surface negative charge is much larger than the edge positive charge, a stable sol state is obtained in which the platelet surface negative charge is dispersed to primary particles by the electric discharge force between the platelet negative charges. However, when the particle concentration or the ion concentration is increased, the repulsive force due to the surface negative charge decreases, and the edge of the other positively charged platelet is electrically connected to the negatively charged platelet surface. It becomes possible to form a so-called card house structure, and to exhibit thickening and thixotropic properties. In this way, the bonding of the card house structure is due to the electric attraction force, so this dispersion shows structural viscosity in the low shear region, and in the high shear region, the bond is separated and becomes a sol state, showing excellent thixotropy. it is conceivable that.

[0010] Synthetic hectorite belonging to the smectite clay mineral is a two-dimensional platelet having a primary particle of about 1 nm in thickness, that is, a square or disk-shaped microplate, and one side or a diameter of the plate surface is extremely fine as 20 to 40 nm. In addition, since the platelets repel each other electrostatically due to surface negative charges and form a stable sol in the aqueous phase, substantially no sedimentation of particles occurs. For this reason, the smectite-based clay mineral expresses an appropriate thixotropy by being colloidally dispersed in the aqueous composition of the present invention.As a result, the coatability is good, and the adhesion amount unevenness and film defects are reduced. It is judged that a small and uniform film formation was realized. Further, the obtained film is formed of a flat plate-shaped smectite-based clay mineral microplate deposit layer, and exhibits excellent fingerprint resistance and corrosion resistance because of its excellent smoothness and barrier properties. Seem.

Further, the film comprising the aqueous composition for film treatment of the present invention is characterized by exhibiting high conductivity (low electric resistance value) because this film has smectite having a negative surface charge. Multi-layered sandwich structure consisting of platelet deposition of clay-based clay minerals and component layers containing divalent or higher-valent metals, in other words, small-sized smectite-based clay minerals in which a complex compound of divalent or higher-valent metals has a surface negative charge. It is presumed that this is because the film structure is included between the flat plates, which facilitates the movement of electrons.

The complex compound of a divalent or higher valent metal used in the present invention refers to an organic compound or an inorganic compound obtained by chelating a divalent or higher valent metal. As the complex compound of a divalent or higher valent metal, a compound which can be stably compounded in an aqueous liquid, directly or by stabilization, is preferable, and in a state where it is rapidly decomposed by contact with water. Mixing is not preferred. Examples of such a metal complex compound include a metal alkoxide, a metal acetylacetonate in which a part of hydrogen may be substituted with an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group in which a part of hydrogen has 1 to 4 carbon atoms. Metal oxyacetylacetonate, metal carboxylate, metal aminate, metal peroxide, etc. which may be substituted may be used, and these may be blended in a dissolved or dispersed state in the aqueous composition for film treatment of the present invention. I have. Further, in order to suppress the hydrolyzability of these metal complex compounds, they may be formed into an acidic solution or subjected to a water stabilization treatment such as emulsification and dispersion of a solution dissolved in a hydrophobic solvent. Commercial products can also be used as the metal complex compound.

[0013] The metal of the divalent or higher valent metal of the complex compound of the divalent or higher valent metal is not particularly limited as long as it can function as a chelate compound, but is typically magnesium, aluminum, calcium, titanium, vanadium, chromium. , Manganese, iron, cobalt, nickel, copper, zinc, strontium, zirconium, silver, tin, barium, tungsten and the like. The alkoxide of the metal alkoxide is not particularly limited in the number of carbon atoms, but is usually a linear or branched alkoxide having 1 to 6 carbon atoms, for example, methoxide,
Ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, tert
-Butoxide, neopentyl oxide and the like.
Examples of the metal acetylacetonate in which a part of hydrogen may be substituted by an alkoxy group having 1 to 4 carbon atoms (eg, methoxy group, ethoxy group, etc.) include, for example, titanium acetylacetonate, vanadium acetylacetonate and the like. Can be Examples of the metal oxyacetylacetonate which may be partially substituted with an alkoxy group having 1 to 4 carbon atoms (e.g., methoxy group, ethoxy group, etc.) include titanium oxyacetylacetonate and vanadium oxyacetylacetonate. And the like. The carboxylic acid of the metal carboxylate is not particularly limited, but is usually a saturated or unsaturated aliphatic mono- to tricarboxylic acid having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms, in which a part of hydrogen may be substituted by a hydroxyl group. Preferred are, in particular, mono- to penta- and especially mono- to dihydroxy-substituted saturated or unsaturated aliphatic mono- to tricarboxylic acids having 1 to 6 carbon atoms, especially 1 to 4 carbon atoms, for example,
Acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, lactic acid, malic acid, tartaric acid, glycolic acid, glyceric acid, citric acid and the like can be mentioned. As the metal aminate, triethanol aminate or the like is mainly used. Examples of the metal peroxide include peroxides of the above-mentioned metals, for example, magnesium peroxide, titanium peroxide, zinc peroxide and the like.

The metal complex compound is present as an intercalation compound in the film composed of the aqueous composition for film treatment of the present invention by being mainly replaced by the hydrated cation of the smectite clay mineral, Water resistance is significantly improved. If the interlayer ion of the smectite-based clay mineral is a monovalent metal that is easily hydrated, the water resistance of the film is low, and the film may fall off due to environmental humidity, dew condensation water and the like, which is not practical. In other words, the metal complex compound used in the present invention is a film forming process of applying and drying the present aqueous composition,
Any compound that can be replaced with a hydrated cation as an intercalation compound of the smectite-based clay mineral and that can enhance the water resistance of the film can be used. An object that is easily exposed is particularly preferable in terms of the water resistance of the film.

The mass ratio of the smectite clay mineral to the metal complex compound in the aqueous composition for film treatment of the present invention is as follows:
As a mass ratio of the clay mineral / metal in the metal complex compound,
It is preferably from 500 to 5. This mass ratio is 500
When it is larger, generally, divalent or higher valent metal ions are insufficient between the layers of the smectite-based clay mineral, and the water resistance of the film is not sufficiently exhibited. As a result, the corrosion resistance also deteriorates. On the other hand, when the mass ratio is less than 5, generally, uniform appearance, fingerprint resistance and the like are not sufficiently exhibited.

The aqueous composition for film treatment of the present invention is usually a one-part composition as described above, but the smectite clay mineral and the metal complex compound are used as separate systems immediately before use. A film treatment agent of a type used by mixing with the above may be used. That is, the present invention provides, as another aspect, 2
A film treating agent comprising an aqueous solution or aqueous dispersion of a complex compound of a metal having a valency of at least 2, and a smectite-based clay mineral or an aqueous dispersion thereof.
It includes a coating agent capable of obtaining the above composition by mixing. There is no particular limitation on the film treating agent of the present invention as long as the film treating aqueous composition formed by mixing immediately before use falls within the range of the film treating aqueous composition of the present invention.

As the industrial material to which the aqueous composition for coating treatment of the present invention is applied, most generally, metal materials such as iron and steel, zinc, aluminum, magnesium, stainless steel, tin and titanium, particularly industrially important materials Material, zinc,
Various metal materials such as a plated steel material plated with aluminum or the like and an aluminum die-cast are included, but are not limited thereto, and further include glass, ceramics, and plastics.

The aqueous composition for coating treatment of the present invention can be applied to industrial materials by a commonly used application method, for example, dip coating, spray coating, roll coating, electrostatic coating and the like. Subsequent drying is performed by a commonly used drying method, for example, hot air drying, for example, at about 80 ° C.
It may be performed at about 400 ° C. Dry adhesion is 0.05 ~
About 5.0 g / m ² is suitable for achieving the effects of the present invention.

[0019]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. <Preparation of sample for evaluation> Bead blasting (particle size: 106
-163 μm) treated aluminum die cast material (7
0 × 150 × 0.8 mm) Fine Cleaner 31 manufactured by Nippon Parkerizing Co., Ltd.
5 was immersed in a 2% aqueous solution for 3 minutes and then washed with water to clean the surface. Furthermore, after performing the surface treatment shown in the following Example or Comparative Example, it was set as the sample for evaluation. The coatings of the following Examples and Comparative Examples were performed so that the dry film adhesion amount was 1 to ² g / m ² .

Example 1 Commercially available synthetic hectorite [Si ₈ (Mg _5.34 Li _0.66 )
O ₂₀ (OH + F) ₄ ] Na _0.66 (Primary particle shape: thickness 1
2% aqueous dispersion 5
With respect to 00 g, a zirconium acetate solution was mixed such that the mass ratio of synthetic hectorite / metal became 400, and 1 kg of an aqueous liquid was prepared with the remainder being water. This was spray-coated on the aluminum die-cast material, and then dried in a hot air drying oven at 100 ° C. for 10 minutes. Example 2 A commercially available synthetic hectorite 2% aqueous dispersion (500 g) was mixed with a titanium triethanolamine solution so that the mass ratio of synthetic hectorite / metal became 100,
1 kg of an aqueous liquid was prepared with the remainder being water. This was spray-coated on the aluminum die-cast material, and then dried in a hot air drying oven at 200 ° C. for 10 minutes.

Example 3 To 500 g of a commercially available synthetic hectorite 2% aqueous dispersion, an aluminum carboxylic acid chelate solution (malic acid + tartaric acid (1: 1) was used as a carboxylic acid) was synthesized. The mixture was mixed so that the mass ratio became 40, and the remainder was water to prepare 1 kg of an aqueous liquid. This was spray-coated on the aluminum die-cast material, and then dried in a 300 ° C. hot air drying oven for 5 minutes. Example 4 To 500 g of a commercially available synthetic hectorite 2% aqueous dispersion, a titanium acetylacetonate acidic solution was mixed so that the mass ratio of synthetic hectorite / metal became 10, and the remainder was 1 kg of an aqueous liquid as water. Was prepared. After spray coating this on the aluminum die cast material,
It was dried in a hot air drying oven at 80 ° C. for 20 minutes.

Comparative Example 1 The above-mentioned aluminum die-cast material (the surface of which was cleaned) was used as a comparative sample as it was. Comparative Example 2 Aqueous acrylic resin emulsion containing 20% of colloidal silica (particle diameter: 10 to 20 nm) was spray-coated on the aluminum die-cast material, and then 100
It dried for 10 minutes in the hot air drying oven of ° C. WATERSOL S-74 is an aqueous acrylic resin emulsion.
4 (manufactured by Dainippon Ink and Chemicals, Inc.).

<Test Method> Appearance Judgment The appearance uniformity and transparency of the surface of each sample of Examples and Comparative Examples were visually judged. The criteria were as follows. ：: High transparency, good uniformity of appearance without unevenness. Δ: Transparency or uniformity of appearance is poor, and the appearance of the base material is slightly impaired. X: Transparency and uniformity of appearance are poor, and the appearance of the base material is extremely impaired. 2. Surface electric resistance value Each sample of Examples and Comparative Examples was
The surface electric resistance was measured using staEP MCP-T360 (two-probe probe). The lower the surface electric resistance, the better.

3. Fingerprint Resistance ΔL, a, and b were measured on the surface of each sample of Examples and Comparative Examples using a color chromaticity meter CR-300 manufactured by Minolta. Next, an appropriate amount of Vaseline was applied to the measurement site, and the site was wiped off with gauze. Then, ΔL, a, and b were measured again, ΔE was calculated by the following formula, and this value was used as an index for fingerprint resistance. did.
The lower the value of ΔE, the better the fingerprint resistance performance. △ E = ((L1-L2 ) 2 + (a1-a2) 2 + (b1-
b2) ² ) ^1/2 L1: L value before Vaseline application L2: L value after Vaseline application a1: a value before Vaseline application a2: a value after Vaseline application b1: b value before Vaseline application b2: Vaseline B value after application

4. Film fixation rate The amount of Si attached to each sample of the examples and comparative examples was measured by a fluorescent X-ray analyzer. Next, the sample whose adhesion amount was measured was immersed in a 2% aqueous solution of an alkaline degreaser PALCLEAN 364S manufactured by Nippon Parkerizing Co., Ltd. heated to 60 ° C. for 3 minutes and washed with water to clean the surface. The amount of deposited Si was measured using an apparatus, and the film fixing rate was calculated from the following formula. The higher the film fixing rate, the better. S (%) = (1− (S1−S2) / S1) × 100 S1: Si adhesion amount before alkali degreasing S2: Si adhesion amount after alkali degreasing

[5] Corrosion resistance Each sample of Examples and Comparative Examples was subjected to a temperature of 40 ° C. and a humidity of 98%.
Was subjected to a corrosion promotion test in which the test was held for 120 hours in a thermo-hygrostat, and the degree of generation of corrosion products (rust) after the test was visually evaluated. The criteria were as follows. A: The generation of corrosion products is less than 5% of the total evaluation area. ：: The generation of corrosion products is 5% or more and less than 20% of the total evaluation area. Δ: Corrosion products were generated at 20% or more and 50% of the total evaluation area.
Is less than. ×: The generation of corrosion products is 50% or more of the total evaluation area.

As is clear from the test results in Table 1, the samples of Examples 1 to 4 prepared by using the method of the present invention show good results in all of the film appearance, fingerprint resistance, conductivity and corrosion resistance. Was. On the other hand, Comparative Example 1 has extremely poor fingerprint resistance and corrosion resistance because there is no film component, and Comparative Example 2 has good fingerprint resistance and corrosion resistance due to the resin-based film, but is poor in conductivity because of poor conductivity. It was not a target.

[0028]

[Table 1]

[0029]

As described above, the composition of the present invention can form a film having good uniform appearance and corrosion resistance by a simple method of coating and drying on the surface of industrial materials, especially metal materials. Furthermore, since this film shows extremely good conductivity and anti-fingerprint property, the material design is maintained for a long time by reducing the contamination of hand oil and the like adhering during handling, and good grounding property (conductive property) ) Can be obtained, so that the practical effect is extremely large.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 26/00 C23C 26/00 C (72) Inventor Hiroki Hayashi 1-1-15 Nihonbashi, Chuo-ku, Tokyo F-term (reference) in Japan Parkerizing Co., Ltd. CA62

Claims (5)

[Claims] 1. An aqueous composition for coating treatment comprising a smectite clay mineral and a complex compound of a divalent or higher valent metal. 2. The composition according to claim 1, wherein the mass ratio between the smectite clay mineral and the metal complex compound is 500 to 5 as the mass ratio of the clay mineral / the metal in the metal complex compound. 3. The composition according to claim 1, wherein said metal complex compound is selected from metal alkoxides, metal acetylacetonates, metal oxyacetylacetonates, metal carboxylate, metal aminates and metal peroxides. 4. A film treating agent comprising an aqueous solution or aqueous dispersion of a metal complex compound of a divalent or higher valent metal and a smectite clay mineral or an aqueous dispersion thereof. A film treating agent capable of obtaining the composition according to any one of claims 1 to 3 by mixing. 5. An industrial material having a film formed on the surface thereof using the composition according to claim 1.