JPS63175081A - Coating composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition capable of giving coating film of flexural resistance, by incorporating an aqueous coating resin with fine plastic pigment prepared by curing an amino acid-modified product of methylol melamine to make spherical granules with specified diameter. CONSTITUTION:The objective composition can be obtained by incorporating (A) fine plastic pigment prepared by curing an amino acid (e.g. glycine)-modified product of methylol melamine or initial condensate from said product to make spherical granules with a diameter 0.005-100mu in (B) an aqueous coating resin, etc. The above-mentioned amino acid-modified methylol melamine can be preferably made by reaction of 0.005-3mol. of the amino acid with 1mol. of methylol melamine.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coating composition, and more specifically, to a novel coating composition capable of forming a coating film having excellent physical properties, particularly flex resistance. The purpose is to provide

(Prior art) A large number of paints have been known in terms of form, such as water-based paints, oil-based paints, emulsion paints, ultraviolet curable paints, and powder paints. Paints containing various film-forming resins such as acrylic resins, urethane resins, melamine resins, phenolic resins, and polyester resins are known, and from the viewpoint of the curing mechanism of the coating film, there are room temperature curing types, thermosetting types, etc. Various types are known, such as type and ultraviolet curing type.

Paints generally have film-forming resins, media, colorants, fillers, etc. as their main components, but various additives are also widely used to improve the base coating performance and physical properties of the paint film. .

As a type of additive, for example, plastic pigments such as polyethylene, polyurethane, polyacrylic resin, and epoxy resin are added and used as paint thickeners and anti-sagging agents, or as lubricants for coating films formed. It is used to improve surface smoothness.

Furthermore, it is known that by adding these plastic pigments, the internal stress during curing of the coating film is alleviated, and the bending resistance, adhesion properties, etc. of the coating film are improved.

(Problem to be solved by the invention) It is well known that plastic pigments such as those mentioned above are used as additives in paints. It has poor dispersion stability in the paint, and for example, it floats to the surface of the paint when it is stored, resulting in the need for redispersion treatment when the paint is used.

Furthermore, even if redispersion treatment is performed before coating, plastic pigments often migrate to the coating surface during coating or between coating and complete curing, resulting in lack of uniformity within the coating. Therefore, with conventional plastic pigments,
In particular, it has not been possible to sufficiently prevent the coating film from turning white, peeling, cracking, etc. when a painted plate or the like is bent or bent.

The above-mentioned problems of poor dispersion and non-uniformity of plastic pigments can be improved to some extent by adding surfactants to paints, but the use of these surfactants improves the water resistance and resistance of paint films. This has an adverse effect on solvent properties, coating film strength, etc., and another problem arises in that the surfactant bleeds out onto the coating film surface over time, significantly reducing surface gloss, stain resistance, etc.

Therefore, there is a need for an excellent coating composition that does not cause the above-mentioned problems.

(Means for Solving the Problems) As a result of intensive research in response to the demands of the prior art as described above, the present inventor has adopted a specific plastic pigment as a plastic pigment as a paint additive. The plastic pigment is easily dispersed in the paint without using any surfactant, and no redispersion treatment is required during storage, application, and curing of the paint. Therefore, the added plastic pigment exists uniformly in the coating film obtained with this paint, resulting in the formation of a coating film with excellent bending resistance. Completed the invention.

That is, the present invention provides an amino acid modified product of methylolmelamine or an initial condensate thereof with a diameter of 0.005 to 100 μm.
This is a coating composition characterized by co-producing fine plastic pigments that are hardened into spherical particles of m.

Next, to explain the present invention in more detail, the coating composition of the present invention consists of a film-forming resin, a pigment, a vehicle, and a specific plastic pigment.

For example, as the film-forming resin, any conventionally known resin can be used. For example, as the resin for water-based paints, casein, hydroxyethyl cellulose, water-soluble salts of styrene-maleic acid ester copolymers, (meth)acrylic Water-soluble salt of ester (co)polymer, water-soluble salt of styrene-(meth)acrylic ester latex, water-soluble alkyd resin, styrene-butadiene copolymer latex, (meth)
Examples include acrylic ester copolymer latex, styrene-(meth)acrylic ester copolymer latex, ethylene-vinyl acetate copolymer latex, polyethylene dispersion, and ethylene copolymer dispersion.

For oil-based paints, cellulose acetate buticy 1 resin, nitrocellulose resin, vinyl acetate (co)polymer, styrene (co)polymer, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate system Copolymers, polyvinyl butyral resins, alkyd resins, phenol-modified alkyd resins, styrenated alkyd resins, amino alkyd resins, polyester polymers, polyurethane polymers, acrylic polyol urethane polymers, soluble polyamides Examples include polymers, phenolic resins, rosin-modified phenolic resins, and rosin-modified maleic acid resins.

In addition, organic and inorganic pigments are used as pigments,
For example, organic pigments include phthalocyanine, azo, anthraquinone, perinone/perylene, indigo/thioindigo, dioxazine, quinacridone,
Examples of inorganic pigments include carbon black, titanium oxide, iron oxide, fired pigments, metal powder pigments, and extender pigments.

In addition, all conventional media and various additives can be used as they are.

The plastic pigment used in the present invention and which mainly characterizes the present invention is a methylolmelamine amino acid modified product or its initial condensation product with a diameter of 0.005 to 1.
It is a fine plastic pigment that is hardened into 00 μm spherical particles.

To explain the present invention in detail, [
The term "methylolmelamine" includes not only methylolmelamine, which has 2 to 6 methylol groups per melamine molecule, but also various derivatives of methylolmelamine with modified methylol groups, such as alkoxymethylmelamine, halogenmethylmelamine, etc. It is the meaning.

The amino acid-modified methylol melamine used in the present invention is obtained by adding o, oos to 3 mol of amino acids per 1 mol of methylol melamine during or after the production of methylol melamine. If the amount of the amino acid used is below the above range, a uniform, perfectly spherical plastic pigment cannot be obtained, and the same holds true even if the amount is above the above range. Therefore, in the present invention, the amount of amino acids used is very important.

The amino acids preferably used in the present invention refer to compounds having both an amino group and a sulfonic acid group or a carboxylic acid group in the molecule, such as glycine, alanine, valine, leucine, isoleucine, serine, threonine, cysteine, and cystine. , methionine, aspartic acid, glutamic acid, lysine, arginine, phenylalanine,
Tyrosine, histidine, tryptophan, proline, oxyproline, β-aminopropionic acid, γ-aminobutyric acid, anthranilic acid, m-aminobenzoic acid, p-aminobenzoic acid, aminonaphthoic acid, aminoanthraquinonecarboxylic acid, sulfamic acid, orthanyl It may be any other amino acid or salt such as methanic acid, sulfanilic acid, aminonaphthalene sulfonic acid, aminoanthraquinone sulfonic acid, or a salt thereof.

Such an amino acid modified product of methylolmelamine may be produced according to a conventionally known method, and may be produced by reacting melamine, formaldehyde, an amino acid, and other modifying agents as necessary in an aqueous medium. Can be done. The concentration of the aqueous solution of the amino acid modified product of methylolmelamine and/or its initial condensate obtained in this gap is preferably about 1 to 30 parts by weight.

In order to obtain a plastic pigment from such an amino acid modified product of methylolmelamine, conventionally known methods such as spray-drying such an aqueous solution or dropping the aqueous solution into acidic water and stirring vigorously can be used. This can be done in accordance with.

The above-mentioned plastic pigments are contained in the coating composition of the present invention in an amount of about 1% per 100 parts by weight of the film-forming resin of the coating.
It is preferable to use it in a proportion of ~30 parts by weight, and if the amount is less than the above range, the intended purpose of the present invention, which is to alleviate the internal stress of the coating film and improve the bending resistance of the coating film, is achieved. This is not preferable because the effect is insufficient, and there is little point in using an amount exceeding the above range, which will actually reduce the strength of the coating film.

The plastic pigment can be added to various paints such as paints that have already been prepared, or it can be used from the beginning as a component in the formulation of paints, with the same effect.

Any conventionally known dispersion means may be used as a compounding method, but in the case of the present invention, the above plastic pigment has extremely good dispersibility in the paint, and can be easily mixed by simple stirring. , sufficient dispersion is achieved in a very short time.

(Function) As described above in detail, the plastic pigment used in the present invention has a particle size of 0.005 to 100 μm.
Since it is a fine particle of m and has amino groups and acid groups on its surface, it itself has sufficient surface activity, so it is very well dispersed in paints, and is especially effective in paints. When the liquid medium is water or an aqueous medium, or a polar organic solvent, or a hydrophobic press solvent containing a small amount of a polar organic solvent, the dispersibility of the plastic pigment is even better and almost can be easily and uniformly dispersed in paints without using strong mechanical energy.

(Effect) Therefore, since the plastic pigment in the coating composition of the present invention is uniformly and stably dispersed in the coating composition, it does not float on the coating surface during storage of the coating composition. There is no sedimentation, and of course, such problems do not occur during painting or when the coating film is cured. Because the plastic pigment is uniformly present in the coating film formed by the process, the internal stress of the coating film is sufficiently alleviated, and even when the painted plate is bent or bent, the bent area will not turn white, or It does not peel or crack, and can sufficiently follow the deformation of the object to be coated.

Furthermore, in the coating composition of the present invention, there is no need to use a surfactant for dispersing the plastic pigment, so various problems caused by surfactants do not occur.

Next, the present invention will be specifically explained with reference to Reference Examples, Examples, and Comparative Examples. In the text, parts or % are based on weight unless otherwise specified.

Reference Example 1 40 parts of melamine, 100 parts of 35% formalin, 20 parts of methanol, and 28 parts of water were mixed and stirred, heated to 80° C., and dissolved in a colorless and transparent mixture. Next, this solution was cooled to 45°C, 2.8 parts of sulfamic acid was added and reacted, one drop of the reaction solution was dropped into water and the reaction was carried out until an initial condensate was precipitated, and then a 20% aqueous sodium hydroxide solution was added. 5.8 parts and 20 parts of methanol were added to terminate the reaction.

Dissolve 30 parts of this resin solution in 100 parts of water, spray this solution onto a disk rotating at 18,000 r, p, m, heat it to 110°C, atomize it in the air, and harden it. As a result, a uniform spherical plastic pigment with a diameter of approximately 0.2 to 0.5 μm was obtained.

Reference Example 2 50 parts of an 80% aqueous solution of methylated methylolmelamine resin was diluted and dissolved in 40 parts of a 50% methanol aqueous solution, 2 parts of sulfamic acid was added to the solution, and after reacting at 45 to 50°C for 20 minutes, the 20% 5 parts of aqueous sodium hydroxide solution was added to neutralize. After cooling, 10 parts of methanol was added to terminate the reaction to obtain a solution of the initial condensate. This solution is approximately 4
It had a solids content of 0% and remained in a clear dissolved state even when diluted with water.

100 parts of the above resin solution was diluted with 10 parts of water, and 400 parts of this solution was dropped into water at pH 5.5 to 6.0 at 90°C with vigorous stirring, and cured at 90°C for 1 hour to complete the reaction. After filtration, a plastic pigment with a particle size of about 1.0-1.5 μm was obtained.

Reference Example 3 40 parts of melamine, 100 parts of 35% formalin, 20 parts of methanol and 28 parts of water were mixed and stirred, the temperature was raised to 80°C to make it transparent, the solution was then cooled to 45°C, and 2.5 parts of glycine was added. The reaction is continued until an initial condensate is formed.

Thereafter, 5.8 parts of a 20% aqueous sodium hydroxide solution and 20 parts of methanol were added and stirred to complete the reaction.

400 parts of this solution was doubled with water and the pH was 5.6.
~6.0, dropped into 1,500 parts of water at 90°C with vigorous stirring, cured at 90°C for 1 hour, filtered, and dried to form a plastic resin with a particle size of approximately 0°1 to 0.2 μm. I got the message.

Reference Example 4 2 parts of sulfamic acid was added to 90 parts of a 50% aqueous methanol solution containing 20 parts of methylolmelamine and 20 parts of methylated methylolmelamine, and after reacting at 45 to 50°C for 10 minutes, 5 parts of a 20% aqueous sodium hydroxide solution was added. was added to terminate the reaction.

This reaction solution had a solid content of about 40% and remained a clear solution even when diluted with water.

400 parts of the solution was heated at 50° C. at pH 5.5 to 6.0 for 1.5 hours.
It was added dropwise to 500 parts of water with vigorous stirring, kept at 90°C for an hour, filtered, and dried. ~0.5μm
obtained plastic pigment.

Reference Example 5 50 parts of an 80% aqueous solution of methylated methylolmelamine resin was diluted and dissolved in 40 parts of a 50% methanol aqueous solution, 2.5 parts of glycine was added to the solution, and the mixture was heated at 45°C to 50°C for 20
After reacting for a minute, 5 parts of a 20% aqueous sodium hydroxide solution was added to neutralize.

After cooling, 10 parts of methanol was added to terminate the reaction to obtain an initial condensate. This solution had a solids content of approximately 40% and remained clear and dissolved when diluted with water. 200 parts of the above resin solution was diluted with 200 parts of water, and 400 parts of this solution was dropped into 90°C i, soo parts of water at 5.5 to 6.0 with vigorous stirring. Cured at ℃ for 1 hour, filtered and dried after completion of reaction to give approximately 0.2 μm x 5 μm
A plastic pigment with a particle size of .

Reference Example 6 50 parts of an 80% aqueous solution of methylated methylolmelamine resin was diluted and dissolved in 40 parts of a 50% methanol aqueous solution, 2.5 parts of DL-anirane was added to the solution, and the mixture was heated from 45°C to 50°C.
After reacting for 1 hour, one drop of the reaction solution was dropped into water to polymerize until an initial condensate was precipitated, and then neutralized by adding 5 parts of a 20% aqueous sodium hydroxide solution.

After cooling, 10 parts of methanol was added to terminate the reaction to obtain an initial condensate. This solution had a solids content of approximately 40% and remained clear and dissolved when diluted with water. 200 parts of the above resin solution was diluted with 200 parts of water, and 400 parts of this solution was added dropwise to 1,500 parts of water at pH 5.5 to 6.0 at 90°C with vigorous stirring for 1 hour at 90°C. After curing and completion of the reaction, the mixture was filtered and dried to obtain plastic pigments having a particle size of approximately 0.5 μm to 1.0 μm.

Reference Example 7 50 parts of an 80% aqueous solution of methylated methylolmelamine resin was diluted and dissolved in 40 parts of a 50% methanol aqueous solution, 2.5 parts of sodium L-aspartate was added to the solution, and the mixture was heated at 45°C.
After reacting at 50° C. for 20 minutes, 5 parts of a 20% aqueous sodium hydroxide solution was added to neutralize.

After cooling, 10 parts of methanol was added to terminate the reaction to obtain an initial condensate. This solution had a solids content of approximately 40% and remained clear and dissolved when diluted with water. 200 parts of the above resin solution was diluted with 200 parts of water, and 400 parts of this solution was added dropwise to 1,500 parts of water at pH 5.5 to 6.0 at 90°C with vigorous stirring for 1 hour at 90°C. After the reaction was completed, the mixture was cured, filtered, and dried to obtain plastic pigments having a particle size of about 0.1 μm to 0.3 μm.

Reference Example 8 50 parts of an 80% aqueous solution of methylated methylolmelamine resin was diluted and dissolved in 40 parts of a 50% methanol aqueous solution, 2.5 parts of sodium glutamate was added to the solution, and the mixture was heated at 45°C for 5
The reaction was carried out at 0°C for 1 hour.

One drop of the reaction solution was dropped into water and polymerized until an initial condensate precipitated, followed by neutralization by adding 5 parts of a 20% aqueous sodium hydroxide solution.

After cooling, 10 parts of methanol was added to terminate the reaction to obtain an initial condensate. This solution had a solids content of approximately 40% and remained clear and dissolved when diluted with water. The above resin bath [
200 parts of this solution was diluted with 200 parts of water, and 400 parts of this solution was added dropwise to 1,500 parts of water at pH 5.5 to 6.0 at 90°C with vigorous stirring and cured at 90°C for 1 hour to react. After completion, the mixture was filtered and dried to obtain plastic pigments having a particle size of about 0.1 μm to 0.5 μm.

Reference Example 9 50 parts of an 80% aqueous solution of methylated methylol melamine resin was diluted and dissolved with 400 parts of water, and 4 ortanilic acid was added to the solution.
．． 3 parts were added and reacted at 40°C to 45°C for 20 minutes. After reacting until the entire solution became cloudy, 5 parts of a 20% aqueous sodium hydroxide solution was added to terminate the reaction. This solution had a solids content of approximately 8% and remained clear and dissolved when diluted with water.

200 parts of the above resin solution was diluted with 200 parts of water, and 400 parts of this solution was heated to 1,50 ml at 90°C at a pH of 5.5 to 6.0.
It was dropped into 0 parts of water with vigorous stirring and cured at 90°C for 1 hour, and after the reaction was completed, it was filtered and dried to give a particle size of about 1.0 μm or more.
A plastic pigment with a particle size of 3.0 μm was obtained.

Reference Example 10 50 parts of an 80% aqueous solution of methylated methylolmelamine resin was diluted and dissolved in 400 parts of water, and 4.0% methanic acid was added to the solution.
3 parts were added and reacted at 40°C to 45°C for 20 minutes.

After reacting until the entire solution became cloudy, 5 parts of a 20% aqueous sodium hydroxide solution was added to terminate the reaction. This solution had a solids content of approximately 8% and remained clear and dissolved when diluted with water. Dilute 200 parts of the above resin solution with 200 parts of water, and add 400 parts of this solution at pH 5.5 to 6.0.
It was dropped into 1,500 parts of water at 0°C with vigorous stirring and cured at 90°C for 1 hour. After the reaction was completed, it was filtered and dried.
A plastic pigment with a particle size of approximately 1.0 μm to 2.5 μm was obtained.

Reference Example 11 50 parts of an 80% aqueous solution of methylated methylolmelamine resin was diluted and dissolved with 400 parts of water, 4.3 parts of sulfanilic acid was added to the solution, and the mixture was reacted at 40°C to 45°C for 20 minutes. After reacting until the entire solution became cloudy, 5 parts of a 20% aqueous sodium hydroxide solution was added to terminate the reaction. This solution had a solids content of approximately 8% and remained clear and dissolved when diluted with water. Dilute 200 parts of the above resin solution with 200 parts of water, and add 400 parts of this solution to a pH of 5.5 to 6.0.
It was dropped into 1,500 parts of water at 90°C with vigorous stirring and cured at 90°C for 1 hour. After the reaction was completed, it was filtered and dried to obtain plastic pigments with a particle size of about 2.0 μm to 3.0 μm. Obtained.

Reference Example 12 In place of sulfanilic acid in Reference Example 11 above, valine, serine, cysteine, phenylalanine,
Similar plastic pigments were obtained using γ-aminobutyric acid and p-aminobenzoic acid.

Example 1 Polyester varnish (Beccolito 6402-50,
(manufactured by Dainippon Ink Chemical) 100 parts Titanium oxide pigment (CR-93, manufactured by Ishihara Sangyo) 90 parts Kijirol/butyl cellosolve (4/l) solvent 30 parts Weigh the above ingredients into a glass container and add an appropriate amount of glass peas. Mix and disperse for 30 minutes using a paint conditioner, and then add 45 parts of polyester varnish (Betsucolite 6402-50), 15 parts of melamine varnish (Super Beckamine J-820) and Reference Example 1.
X parts of the plastic pigment were added and mixed with a paint conditioner for an additional 5 minutes to prepare various coating compositions shown in Table 1 below containing various amounts of the plastic pigment.

Next, each of the above coating compositions was applied onto a steel plate (Bonde #37 treatment) that had been degreased using Kijiroll, using a bar coater, to a dry film thickness of 16 to 18 μm, and after being left for 5 minutes, it was heated at 240°C. Bake hardening was performed for 3 minutes, and the tests shown in Table 1 below were conducted, and the results shown in Table 1 below were obtained.

γ 1 - 1 ward, 1 armpit -" Once, 1 No, X, I II I
II IV Vl 089'
J4HO△ to 2 3.7 87%
4H○ OO37,590$4)1 0
0 04 15, (188414HOO○In addition, in the above table, the part
is pencil hardness, ■ is adhesion by cellophane tape goblin peel test, and ■ is Dupont convex 50c.
+nIs the impact peeling strength when peeling off cellophane tape, and ■
shows the results of the vise fold test. In the table, ◯ indicates good quality, and △ indicates slightly poor quality.

As is clear from Table 1 above, the coating composition of the present invention was superior in impact strength and vice folding strength compared to the coating composition to which no plastic pigment was added.

Example 2 Acrylic varnish (Acridic A-602-50, manufactured by Dainippon Ink Chemical) 100 parts Titanium oxide (GR-93, manufactured by Ishihara Sangyo) 80 parts Cyanine Blue (4940, manufactured by Dainichi Seikagaku Kogyo) 2 parts Kijiroru 30 parts of the above ingredients were placed in a ball mill, an appropriate amount of magnetic poles were added, and the mixture was mixed and dispersed for 12 hours. Furthermore, 19 parts of acrylic varnish (Acridic A-602-50), 21 parts of melamine varnish (Super Hetsukamine J-820, manufactured by Dainippon Ink Chemical Co., Ltd.), and part X of the plastic pigment of Reference Example 2 or commercially available high-density polyethylene plastic. An additional 3287 parts of Pig was added and mixed for 5 hours to prepare coating compositions containing various amounts of plastic pigment. The above coating composition was applied immediately after production and for one week at room 1 (23~
We conducted various observations and tests on the properties of the paint after being left at 26°C and on the paint film after painting using conventional methods.
Obtained the results in the table.

Koganryu Ward ■ 100--93X △ 2 3.5 0 0 0 92 ×
03 7.0 0 00 93 Δ
04 15.0 0 00 93
△ 05 0 3.5 0 Δ
51 0 △6 0 7.0
0X 230 Δ Note that the dispersibility in Table 1 above indicates the dispersibility of the plastic pigment immediately after the coating composition was produced, and the dispersibility (■) indicates the dispersibility one week after production. The test items are 60° gloss, ■ is abrasion resistance, and ■ is the result of a vise fold test.

As is clear from the results in Table 2 above, coating compositions (5) and (6) using commercially available plastic pigments
In contrast, in the case of the coating compositions (2) to (4) of the present invention, the plastic pigments rose to the surface after approximately one week had passed after the coating material was manufactured, and the dispersion stability was poor. No such separation of the plastic pigment occurred. Furthermore, in the coating film test, the gloss of the coatings using commercially available plastic pigments was significantly lowered, and this was due to the plastic pigments floating on the coating surface. Furthermore, the abrasion resistance is very good, and this is also due to the presence of a large amount of plastic pigment on the coating surface, which increases the surface smoothness. Furthermore, in the vise folding test, the coating composition of the present invention showed very good results, whereas the coatings (5) and (6) containing commercially available plastic pigments were inferior. .

From the above results, in the paint composition of the present invention, the added plastic pigment is stably and uniformly dispersed in the paint, and as a result, the internal stress of the formed paint film is significantly alleviated. It had excellent bending resistance.

Example 3 In the same manner as in Examples 1 and 2, various coating compositions of the present invention were prepared using the plastic pigments of Reference Examples 3 to 12, and the results were as good as in Examples 1 to 2. The results obtained were as follows.

Patent applicant: Dainichiseika Kogyo Co., Ltd., +1・n Agent: Patent attorney Yoshi 1) Katsuhiro, -・shi□, j1,
? 1rr! −

Claims (1)

[Claims] A coating composition comprising fine plastic pigments obtained by curing an amino acid modified product of methylolmelamine or an initial condensate thereof into spherical particles having a diameter of 0.005 to 100 μm.