JPH02120368A - Pigment composition for water-based metallic coating material - Google Patents

Abstract

PURPOSE:To obtain a pigment composition which has excellent storage stability and can give a metallic coating film excellent in intercoat adhesion and water resistance by using an aluminum pigment composition subjected to a specified treatment as a component of a water-based metallic coating material. CONSTITUTION:This water-base metallic coating material contains at least one organic phosphoric ester (A) having a saturated aliphatic ester residue and at least one organic phosphoric ester (B) having an unsaturated aliphatic ester residue in an amount corresponding to an (A) to (B) weight ratio in the range of 0.05-20 and being 0.05-20wt.% based on an aluminum powder. The organic phosphoric ester used is adsorbed on the surface of an aluminum pow der, whereby it can give thereto a surface protection effect of controlling the reaction of the aluminum powder with water and the water resistance of a coating film can be improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a pigment composition for water-based metallic paints, and more particularly, to a pigment composition for water-based metallic paints, which has excellent water resistance and hot water resistance, and which is composed of an oil-based clear paint. The present invention relates to a pigment composition for a water-based metallic paint that can provide a water-based metallic paint film of a base coat layer with excellent adhesion to a film.

[Conventional technology]

In recent years, in the field of paints, water-based paints that contain very little or no organic solvent have been increasingly used as a resource-saving and pollution-free measure. In addition, due to remarkable technological advances in resins for water-based paints, water-based paints have been developed that can surpass the high-class finish that could previously only be achieved with oil-based paints or solvent-based paints. direction is becoming stronger and stronger.

Conventionally, aluminum pigments used in water-based metallic paints have been made using saturated or unsaturated fatty acids such as stearic acid or oleic acid, or their derivatives as a surface treatment agent, and adding surfactants to this to give them water dispersibility. compositions have been used. However, these water-dispersible aluminum pigments have the disadvantage of low storage stability, especially in water-based paints, which may result in decreased pigment dispersion or generation of large amounts of gas during storage. As a result, the properties of the paint were significantly impaired.

Subsequently, G 1t of polyamide, aliphatic amide, fluorine, silicone, etc., as described in U.S. Pat. No. 3,839,254, was developed to improve the storage stability of metal powder pigments.
21, a method using a perfluorinated alkyl wetting agent such as NtHF in U.S. Patent No. 3,926,874, and a method using a perfluorinated alkyl wetting agent in U.S. Pat. Methods using ionic wetting agents have been disclosed, but none of them have been found to have a sufficient effect of improving storage stability, and they have had the problem of poor wetting of metal powder pigments with water. Sarashiko, JP-A-61-
No. 29607 discloses a method of using a phosphoric acid ester of caprolactone for the purpose of suppressing the reaction between metal powder pigments and water and improving storage stability.
JP-A No. 61-4777 also describes a method using diethylamine adducts of octylphenyl dihydrogen phosphate and bis(octylphenyl hydrogen phosphate) for the same purpose.
No. 1 discloses a method using a reaction product of orthophosphoric acid or phosphoric acid monoester and an Epoquin compound, and JP-A-61-29166 discloses a method using a reaction product of styrene-allylic alcohol and p-tert. - Methods using reaction products of amylphenol and orthophosphoric acid or phosphorus pentoxide have been disclosed, but in either case, the desired improvement effect is insufficient, or a relatively improvement effect is observed. However, when used in water-based paints, there are problems with the performance of the resulting coating film, such as adhesion, water resistance, hot water resistance, etc., and it cannot be put to practical use.

The conventionally known method for forming metallic coatings is a one-coat process in which a metallic paint containing a metallic pigment is applied directly to the object to be coated or on the surface of a hardened intermediate coating, and then cured by heating. 1-bake method (ICIB), 2-coat 2-beta method (2C2B), in which metallic paint is applied, it is heated and cured, and then a clear paint is applied to form a transparent film, and then heat-cured again (2C2B), both Etto paints The 2-coat-in-1-beta method (2CIB), in which the paint is coated in the above order and cured at the same time by heating once; the coated surface formed by the 2-coat-in-1 hake method is further coated with clear paint and heated again. Curing 3 coats 2 coats E (3
02B), and among these, 2 was selected after comprehensively judging the number of painting steps, finished metallic appearance, coating performance, etc.
The method of forming metallic 1llQ using CIB is most commonly used. At this time, thermosetting paints containing metallic pigments are called base coats, and clear paints are called top coats, and both base coats and top coats have been solvent-based paints containing oil-based organic solvents.

However, with the recent trend toward water-based paints, metallic base coat paints have become water-based, and the base coat is painted with a water-based metallic paint, and the top coat is coated with an oil-based solvent-based clear paint and cured by heating. The two-coin, one-beta system is becoming the mainstream.

This method of forming a film using 2CIB of a water-based base coat and an oil-based top coat is more effective than the conventional method of forming a film using 2CIB of an oil-based base coat and an oil-based top coat. The compositions are different, the compatibility is poor, and the adhesion between the two coats is extremely poor. In addition, compared to oil-based base coats, water-based base coats retain their inherent hydrophilic properties as water-based paints even after heat curing, so they have problems with water resistance, hot water resistance, etc. The current situation is that improvements are desired. In the case of water-based room coatings, there is less freedom in solvent selection, and water has a large latent heat of vaporization, so the rate of evaporation of water from the coating film is slow. This is considered to be a factor that worsens the condition.

[Problem to be solved by the invention] As mentioned above, many technologies have been disclosed regarding aluminum pigments intended for use in water-based paints, but the storage stability and storage stability of the pigments and water-based paints using the pigments are unclear. No aluminum pigment has been found that satisfies both aspects of coating film performance, which greatly influences the finish.

In particular, in the coating film formation method in which a top coat layer made of an oil-based clear paint is formed on a base coat layer made of a water-based metallic paint, the adhesion between the eyebrows of the top coat layer and the base coat layer, the water resistance of the paint film, and the hot water resistance are No aluminum powder has been found that is extremely effective as a pigment component in water-based metallic paints that can provide extremely good metallic paint films.

The object of the present invention is to provide a new aluminum pigment that eliminates the drawbacks of the prior art. That is,
Provided is a novel aluminum pigment that has excellent storage stability in water-based metallic paints and is capable of providing metallic paint films with excellent glabella adhesion, water resistance, and hot water resistance in the above-mentioned two-layer paint films, etc. It is to be.

[Means to solve the problem]

As a result of intensive research in order to solve the above problem, the present inventors discovered that the purpose could be achieved by using a specially treated aluminum pigment composition as a pigment component of a water-based metallic paint. The present invention has been accomplished.

That is, the present invention provides at least one selected from the group of (A) organic phosphoric esters having saturated aliphatic ester residues and (B) the group of organic phosphoric esters having unsaturated aliphatic ester residues. At least one selected species, (A)/
The present invention relates to a pigment composition for an aqueous metallic paint, characterized in that the amount of M (B) is in the range of 0.05 to 20% by weight based on the aluminum powder.

The present invention will be explained in detail below.

As the aluminum powder used in the present invention, it is suitable that it has surface properties, particle size, and particle shape required for metallic pigments, such as surface gloss, whiteness, and brightness. In general, scaly aluminum powder obtained by grinding raw aluminum powder in a hydrocarbon solvent in the presence of a grinding aid using a known wet ball mill method called the Hall method can be used, but the grinding method is It is not particularly limited,
For example, scaly aluminum powder obtained by wet or dry pulverization methods such as a roller mill method, a high-speed rotary pulverization method, a media agitation mill method, and an air flow pulverization method can also be used.

The organic phosphoric acid ester in the present invention adsorbs onto the surface of aluminum powder, thereby providing a surface protection effect that suppresses the reaction between the aluminum powder and water, and improving the water resistance performance of the coating film. be.

Preferred organic phosphoric acid esters are compounds represented by the general formula. Here, R represents hydrogen, a saturated aliphatic group having 6 to 24 carbon atoms, an unsaturated aliphatic group having 6 to 24 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, and m is O
~20, R2 and & may be the same or different, hydrogen, saturated aliphatic group, unsaturated aliphatic group, or RIA
) fi (where R, A and m are as shown above).

Examples of the saturated aliphatic group in R, R, R; include octyl, decyl, lauryl, cetyl, stearyl,
Examples include behenyl, aracyl, octadecyl, and the like.

Examples of unsaturated aliphatic groups for R, R, and R2 include physeteryl and oleyl.

As A, ethylene and propylene are preferable.

As a specific compound, esters having the above-mentioned saturated aliphatic group or unsaturated aliphatic group of phosphoric acid as an ester residue, or esters obtained by adding ethylene oxide to these ester residues are preferable.

The organic phosphoric ester may be a mono-, di-, or triester, or a mixture thereof, or a mixture of different types of organic phosphoric esters.

Particularly preferable organic phosphoric acid esters include carbon atoms of 6 to 2.
4 saturated aliphatic alcohol and/or carbon number 6-24
monoesters or diesters of unsaturated aliphatic alcohols or mixtures thereof.

Furthermore, since these organic phosphoric acid esters exhibit acidity in aqueous solutions, they also contain ammonium hydroxide, sodium hydroxide, potassium hydroxide, dibutylamine, triethylamine, monoethanolamine, jetanolamine, triethanolamine, morpholine, etc. It can be used after being neutralized with an inorganic or organic basic substance.

The phosphoric acid ester of aluminum' is composed of (A) at least one or more organic phosphoric esters having a saturated aliphatic ester residue and (B) an unsaturated aliphatic ester residue. The above-mentioned (
The weight ratio A)/(B) should range from 0.05 to 20, preferably from 0.1 to 1o. When it is greater than 20, the adhesion between the glabella and the top coat layer formed from the aqueous metallic paint containing the composition is reduced, and when it is less than 0.05, the aqueous metallic paint containing the composition is degraded. This is not preferable because it reduces the water resistance and hot water resistance of the formed coating film. This is thought to be because the adsorption to the aluminum powder surface changes depending on the combination of ester residues in the phosphoric ester.

Further, the organic V4 acid ester is used in an amount of 0.05 to 20% by weight, preferably 0.1 to 10% by weight based on the aluminum powder.
must be within the range. o, below the osi amount%,
The surface protection effect is low, and reaction suppression with water is poor.
If it exceeds 20% by weight, it is not preferable because the water resistance, hot water resistance, and glabella adhesion with the top coat layer of the coating film formed from the water-based metallic paint mixed with the composition are reduced.

There are no particular limitations on the method of adding the organic phosphoric acid ester to the aluminum powder. Generally, scaly aluminum powder is produced by putting raw aluminum powder and a grinding aid to increase grinding efficiency into a grinder such as a ball mill. For example, it is processed by wet grinding in a hydrocarbon solvent or in a nitrogen atmosphere. A dry grinding method is used. As grinding aids at this time, saturated or unsaturated fatty acids, aliphatic amines, fatty acid metal salts, etc. are generally used, but these are also surface treatment agents that adsorb to the surface of the aluminum powder and provide a surface protection effect. . The organic phosphoric acid ester can be used alone or in combination with these fatty acids or fatty acid derivatives.

On the other hand, a surfactant for imparting water and water dispersibility to an organic phosphoric acid ester to aluminum powder that has already been surface-treated using a fatty acid or a fatty acid derivative;
Alternatively, it can be added later together with an additive such as a hydrating alcohol. As the post-addition operation, a kneading operation of kneading the aluminum powder and the additive containing the organic phosphate ester to form a paste with high viscosity, a dispersion operation of forming a slurry liquid with low viscosity, etc. can be used.

In the present invention, the surfactant for making the product water-soluble is not particularly limited, but it is preferable to use a nonionic surfactant from the viewpoint of storage stability. However, when using a hydrating alcohol that is miscible with hydrocarbon solvents and water in appropriate proportions and can completely dissolve organic phosphoric acid esters, or when a surfactant is pre-contained in a water-based paint containing aluminum pigment, It may not be an essential component depending on the type of paint or water-based paint. As the surfactant, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene glycol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, etc. can be used. The effective addition amount in terms of improving the water dispersibility of the aluminum powder is in the range of about 1 to 15% by weight based on the aluminum powder. Examples of the hydrating alcohol include ethanol, (iso)propanol, (iso)butanol, (iso)amyl alcohol, ethyl cellosolve, butyl cellosolve, polyoxyethylene glycol, polyoxypropylene glycol, ethylpropylene glycol, etc., or mixtures thereof. can be used.

Specific examples of hydrocarbon solvents include aliphatic or aromatic hydrocarbon oils used as grinding oils for mineral spirits, solvent naphtha, HAWS, LAWS, and the like.

The aluminum pigment composition of the present invention may contain other additives that are commonly used in the field, such as known leveling agents, leafing stabilizers, thickeners, coloring pigments, etc., and do not impair the effects of the present invention. What is not there,
It may be added as long as the amount is sufficient. Coloring pigments include titanium white, zinc white, navy blue, red iron, calcium carbonate, cadmium yellow, cadmium red, barium sulfate, lead sulfate, calcium silicate, ultramarine blue, cobalt bioleft, manganese purple, burr essence such as burr mica, etc. Inorganic pigments and vat dyes, isoindolinones, quinacridones, condensed azos, insoluble azo pigments, copper phthalocyanines, anthraquinones, indigos, vilanthrones, perylenes, basic dyes with lakes and acids. For dyeing, there are lakes, mordant dye lakes, etc.
It is preferable to select one from among the materials according to the purpose and use. However, in this case, it is necessary to appropriately select the type and amount so as not to impair the effects of the present invention.

1. Base coat) The water-based metallic paint containing the aluminum pigment composition in the present invention is a paint formed by a paint-forming technique normally employed in the field, and the water-based metallic paint containing the aluminum pigment composition in the present invention In addition to these, various additives are required depending on the purpose and use.
For example, dispersants, wetting agents, leveling agents, thixotropic agents, thickeners, anti-sagging agents, anti-mold agents, ultraviolet absorbers, film-forming aids, other organic solvents, etc., organic solvents other than the above aluminum pigments, etc. or adding inorganic pigments, or
It can be obtained without addition. Examples of organic and inorganic pigments include the colored pigments mentioned above which can be added to aluminum pigment compositions.

Here, the water-based paint resin refers to a water-soluble resin or a water-dispersible resin, which may be used alone or as a mixture.The types thereof vary widely depending on the purpose and use, and there are no particular limitations. Generally, thermosetting acrylic-melamine resins are most commonly used as water-based resins for base coats used in coating film formation by the two-coat, one-beta system.

Comparing the amount of organic solvent contained in oil-based base coat paint and oil-based top coat paint, the amount of organic solvent contained in oil-based base coat paint is significantly higher. It becomes possible to significantly reduce the amount of organic solvent used in a coat-and-hake coating system. On the other hand, since oil-based paints are superior in terms of film performance, organic solvent-based paints using oil-based thermosetting acrylic-melamine resins have been most commonly used as top coat paints. but,
-In order to comply with increasingly strict solvent emission regulations,
So-called high-solid oil-based paints containing less solvent, such as high-solid acrylic-melamine resin paints and high-solid urethane resin paints, are considered to be effective.

〔Example〕

Innumerable combinations of embodiments of the present invention are possible within the scope of the present invention, and typical examples thereof will be described below with reference to Examples. However, the present invention is not limited to these examples. In addition, the III determination and evaluation method of various characteristics used in the following examples is shown below.

■Characteristics and measurement and evaluation methods of aluminum pigment compositions (1) Water dispersibility test Sample 43 g of F4 was taken into a 50 ml Nessler tube, and some water was added for preliminary dispersion. Thereafter, water was added up to the 50 ml mark, shaken well, and allowed to stand. After 5 minutes, the dispersion state of the aluminum pigment particles was visually judged.

(2) Water stability Collect 20 g (65% of heating residue) of aluminum face (14 base) in a 200 m-1 Erlenmeyer flask, and add 10 g of pure water.
Add 0ml and shake vigorously to disperse the sample. Attach a graduated pipette with a rubber stopper and place it in a constant temperature bath at 60℃? t'tR and observe the state of gas generation after standing for 24 hours.

(3) Storage-stable aluminum pigment paste was placed in a 500ml glass S container and its properties deteriorated after storage for 6 months at room temperature.

■Measurement and evaluation method of paint and paint film performance (l) Method for creating a 2-coat, 1-bake paint film The water-based metallic paint was cleaved using the following formulation, and the test aluminum pigment composition (1)
) In addition to evaluating the gas generation of the paint, we created a V crotch using the two-coat one-bake method using the oil-based clear paint of formulation B, and evaluated (2) the appearance of the paint film, (3) the adhesion, and! 4) Hot water resistance was evaluated.

AA <base coat) Test aluminum pigment composition 12.0 parts by weight (
Heating residue 65%) Water-soluble acrylic resin 104.4 ~ (
Heating residue 60%) Water-soluble melamine resin 15.6〃(
(Heating residue: 100%) Total B (Coat) Oil-based acrylic resin (Heating residue: 50%) Oil-based melamine resin (Heating residue: 50%) 190.0 〃 321.0 〃 320.0 parts by weight 80 .0ノ! Xylene 350.0 = Total 750.0 In addition, when creating a coating film using the 2-coat 1-bake method, after spray-coating the above formulation A on the coating plate, spray-coating formulation B in a wet-on-wet manner, and leaving it at room temperature. After setting for 30 minutes at 140℃, it was baked for 20 minutes.

(2) Measurement and evaluation method of paint and coating performance (a) Gas generation of paint Pour 100ml of the test paint into a 200ml Erlenmeyer flask, attach a graduated pipette with a rubber stopper, and gas generation after leaving at 50℃ for 24 hours. Observe the condition.

(b) Appearance of paint film Comparative observation is made between a paint film painted immediately after blending the paint and a paint film painted using a paint that has been left at room temperature for 3 months.

(c) Adhesiveness After immersing the coated plate in warm water at 80° C. for 1 hour and leaving it to dry at room temperature for 8 hours, a cellophane tape with cross-scant peeling test is performed to compare and observe the peeling state of the coating film.

(d) After immersing the coated plate in hot water at 80'C for 8 hours, the appearance and metallic feel of the coated film were comparatively observed, and the gloss reduction rate R of the coated film surface was measured using a 60'-60" gloss needle. This was used as the standard for hot water resistance.The gloss reduction rate R was determined by the following formula.

Here, Go represents the initial gloss value of the coating surface, and G represents the gloss value of the coating surface after being immersed in warm water for 8 hours.

Examples 1 to 8 Comparative Examples 1 to 7 A mixture of I kg of granular aluminum powder and 2.5 liters of mineral spirit containing 5% by weight of stearylamine was ground in a ball mill for 8 hours, and then: 1 kg of mineral spirit
07! It was washed out and passed through a screen of 325mm and 100mm. Thereafter, the mixture was filtered using a filter press to obtain a filter cake (1) having an aluminum content of 80i%.

For 100 parts by weight of this filter cake <1),
As shown in the table, a predetermined amount of a predetermined phosphoric acid ester and a nonionic surfactant are mixed, water is added and kneaded so that the heating residue becomes 65%, and a paste-like aluminum pigment composition (II) is obtained. I got it.

The resulting aluminum pigment composition (n) was examined for its water dispersibility, water stability, and storage stability as paste properties, and was also examined for gas generation when mixed with water-based paints, and for oil-based paints when water-based metallic paints are used as base coats. We investigated the appearance, adhesion, and hot water resistance of the paint film created by a two-coat one-bake method using clear paint as the top coat.
The results are shown in Table 1.

(The following is a blank space) [Effects of the Invention] The pigment composition for water-based metallic paints of the present invention forms a thin and dense film of an organic phosphate ester on the surface of an aluminum powder and is covered with various substituents of the organic phosphate ester. ing. Therefore, the aluminum pigment composition of the present invention has excellent gas generation in an aqueous medium or water-based paint and long-term storage properties, and also significantly improves the physical properties of the coating film when used as a water-based metallic paint. As a result, it is possible to provide a water-based metallic paint suitable for use as a base coat in the two-coat, one-bake method, which is the most common method for forming metallic paint films.

Claims (1)

[Claims] (1) (A) at least one selected from the group of organic phosphoric esters having a saturated aliphatic ester residue; and (B) at least one selected from the group of organic phosphoric esters having an unsaturated aliphatic ester residue; A pigment for water-based metallic paints, characterized in that it contains at least one pigment in an amount of (A)/(B) in a weight ratio of 0.05 to 20, based on the aluminum powder, in an amount of 0.05 to 20% by weight. Composition.