JP2002302638A - Aqueous coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material having an excellent weather resistance and antifouling property and a good adhesion to various coated films. SOLUTION: The aqueous coating material contains a copolymer (A) obtained by polymerizing from 5 to 80 mass % t-butyl (meth)acrylate (a), from 0.1 to 10 mass % ethylenically unsaturated monomer having a piperidyl group (b), from 0.1 to 25 mass % ethylenically unsaturated monomer (c) having hydroxyl group (c), from 0.1 to 10 mass % ethylenically unsaturated carboxylic acid monomer (d) and from 0 to 94.7 mass % another ethylenically unsaturated monomer (e) [provided that the total of components (a)-(e) is 100 mass %].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous coating material having excellent weather resistance and stain resistance, and more particularly to a metal, glass, porcelain tile, concrete, siding board, and the like.
The present invention relates to an aqueous coating material that can be used for surface finishing of various materials such as extruded plates and plastics, and is mainly used for protection of building bodies such as buildings and civil engineering structures.

[0002]

2. Description of the Related Art In recent years, in the field of paints used for buildings and civil engineering structures, organic solvents have been used in combination with solvents for the purpose of reducing the health hazards of painters and migrants and reducing air pollution. Conversion from a solvent-based paint to a water-based paint using water as a solvent. In addition, in order to respond to the need for long-term protection of the aesthetics of buildings from the need for resource conservation and energy saving, and to respond to the needs of users for a long period of time, water-based coatings for top coats using silicone and fluorine-based resins with excellent weather resistance have been developed. Development is progressing, and market development is also progressing.

On the other hand, an aqueous coating material using a relatively general-purpose (meth) acrylic resin and having excellent weather resistance is disclosed in Japanese Patent No. 2637.
No. 574, which discloses an excellent water-based paint using a copolymer emulsion of a cycloalkyl group-containing polymerizable monomer and a sterically hindered polymerizable monomer having a piperidyl group. It is described that it exhibits excellent weather resistance.

Further, Japanese Patent Publication No. 3-46506 discloses that
It is described that weather resistance can be improved by adding a hindered phenol-based antioxidant and a benzotriazole-based ultraviolet absorber to a coating resin containing butyl methacrylate as an essential component.

Japanese Patent Application Laid-Open No. Hei 4-233981 discloses a (meth) method having a branched alkyl group having 3 to 5 carbon atoms.
An aqueous composition is described in which an acrylate monomer and a methacrylate monomer having an alkylene oxide group are copolymerized as essential components.

[0006]

SUMMARY OF THE INVENTION However, Patent 2
When using a water-based paint described in JP-A-637574 for the top coat, when a base coat or an intermediate paint is applied for the purpose of imparting substrate protection or improving water permeability, it is conventionally generally used. Intermediate coatings and undercoating coatings have a problem that they are easily peeled off due to insufficient adhesion with the waterborne topcoating coating. There has been a problem that a special intermediate coating or undercoat must be used. In addition, in terms of stain resistance, conventional aqueous (meta)
It was not satisfactory without any difference from acrylic resin.

[0007] Further, in the coating composition described in Japanese Patent Publication No. 3-46506, when the additives such as an antioxidant are blended, the additives bleed out of the coating film with the passage of time. Is difficult to maintain the weather resistance, furthermore, the additive is hard to dissolve in water which is the main medium of the water-based paint. Must be dispersed in water in advance, and the production method is complicated, and there is also a problem in the stability of the produced paint.

The aqueous composition described in Japanese Patent Publication No. 4-233981 has been developed for printing inks, and has problems in weather resistance, water resistance, etc. when used as a coating material for building materials.

Further, when a conventional acrylic water-based paint is applied on a paint film coated with a fluorine-based paint for the purpose of repair or the like, the paint film of the acrylic water-based paint is different from the paint film of the fluorine-based paint. However, there is a problem that peeling is liable to occur when the recoating is performed directly because of poor adhesion.
In addition, conventional water-based paints with excellent weather resistance can extend the period of repainting because the deterioration rate of the paint film is slow, but the paint film itself is deteriorated because the paint film is easily stained. Despite the lack, there was a case where repainting was necessary at the stage where the appearance was impaired by dirt.

An object of the present invention is to solve the above problems,
The paint film has no bleed-out material, has excellent weather resistance and stain resistance, and has good adhesion to films made of various paints such as acrylic, silicone and fluorine. Is to provide an aqueous coating material that can be formed.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies with the aim of solving the above problems, and as a result, have found that an aqueous coating material containing a copolymer obtained from a monomer having a specific structure has been developed. The formed film has excellent weather resistance and stain resistance, and has been found to have good adhesion to films formed with various types of paints, thereby completing the present invention.

That is, the present invention relates to an ethylenically unsaturated monomer (a) represented by the following general formula (I): 5 to 80% by mass.
And CH ₂ ＣＲCR ¹ —COO—C (CH ₃ ) ₃ (I) wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. Monomer (b) 0.1 to 10% by mass, hydroxyl group-containing ethylenically unsaturated monomer (c) 0.1 to 25% by mass, and ethylenically unsaturated carboxylic acid monomer (d) 0.1. 1 to 10% by mass, and other ethylenically unsaturated monomers (e) 0 to 9
An aqueous solution characterized by containing a copolymer (A) obtained by polymerizing 4.7% by mass (the total of the mass percentages of the monomers (a) to (e) is 100% by mass). It is a covering material.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymer (A) which is a main component of the aqueous coating material of the present invention comprises an ethylenically unsaturated monomer (a) represented by the above general formula (I) and a piperidyl group. Having an ethylenically unsaturated monomer (b), an ethylenically unsaturated monomer having a hydroxyl group (c), an ethylenically unsaturated carboxylic acid monomer (d), and optionally other ethylenically unsaturated monomers. It is obtained by polymerizing the monomer (e) and is composed of a repeating unit derived from each monomer unit.

The copolymer (A) used in the water-based coating material of the present invention has a total monomer content of 100% by mass at the time of polymerization in view of weather resistance and adhesion to a coating film formed by various coating materials. In this case, the content of the ethylenically unsaturated monomer (a) represented by the general formula (I) must be 5% by mass or more, and preferably 10% by mass or more. From the viewpoint of the flexibility of the coating film, the content of the ethylenically unsaturated monomer (a) represented by the general formula (I) needs to be 80% by mass or less, and 70% by mass or less. It is preferred that

The ethylenically unsaturated monomer (a) represented by the general formula (I) includes tertiary butyl (meth) acrylate.

The copolymer (A) used in the water-based coating material of the present invention has a piperidyl group in consideration of the weather resistance of the coating film, when the total amount of the monomers at the time of polymerization is 100% by mass. It is necessary that the content of the ethylenically unsaturated monomer (b) is 0.1% by mass or more, and preferably 0.5% by mass or more. In addition, from the viewpoint of the water resistance of the coating film, the ethylenically unsaturated monomer (b) having a piperidyl group has a content of 10%.
It is necessary to be less than 6 mass%, and it is preferred that it is less than 6 mass%.

The ethylenically unsaturated monomer (b) having a piperidyl group generally has an ultraviolet light stabilizing function, and as the monomer (b), for example, represented by the following general formula (III): Compounds can be used.

[0018]

[Formula 1] (In the formula, R ⁵ represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, X represents an oxygen atom or an imino group, and R ⁶ represents a hydrogen atom or a hydrocarbon substituent having 1 to 20 carbon atoms.) I
Specific examples of the compound represented by II) include 4- (meth)
Acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,
6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2
2,6,6-pentamethylpiperidine, 4-cyano-4
-(Meth) acryloyloxy-2,2,6,6-tetramethylpiperidine and the like. One or more of these may be used in combination.

Further, the copolymer (A) used in the water-based coating material of the present invention has a total monomer content of 100% by mass at the time of polymerization from the viewpoint of improving stain resistance due to hydrophilicity of the coating film. Then, when the ethylenically unsaturated monomer having a hydroxyl group (c)
Must be contained in an amount of 0.1% by mass or more,
Preferably, it is contained in an amount of 0.5% by mass or more. From the viewpoint of the water resistance of the coating film, the content of the ethylenically unsaturated monomer (c) having a hydroxyl group needs to be 25% by mass or less, and preferably 20% by mass or less.

Examples of the hydroxyl group-containing ethylenically unsaturated monomer (c) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate, -Hydroxycyclohexyl acrylate, lactone-modified hydroxyalkyl (meth) acrylate, hydroxyl-terminated polyalkylene glycol mono (meth) acrylate, and the like.
One or more of these may be used in combination.

Further, as the ethylenically unsaturated monomer (c) having a hydroxyl group, a hydroxyl-terminated polyalkylene glycol mono (meth) acrylate may be used in order to exhibit more excellent stain resistance and weather resistance. preferable. Hydroxyl-terminated polyalkylene glycol mono (meth)
As the acrylate, hydroxypolyethylene glycol mono (meth) acrylate, hydroxypolypropylene glycol mono (meth) acrylate, hydroxy (polyethylene glycol-polypropylene glycol) mono (meth) acrylate, hydroxypoly (ethylene glycol-propylene glycol) mono (meth)
Acrylate, hydroxy (polyethylene glycol-
Poly (tetramethylene glycol) mono (meth) acrylate, hydroxypoly (ethylene glycol-tetramethylene glycol) mono (meth) acrylate, hydroxy (polypropylene glycol-polytetramethylene glycol) mono (meth) acrylate, hydroxypoly (propylene glycol-tetra) Methylene glycol) mono (meth) acrylate and the like. One or more of these can be used in combination as needed.

The copolymer (A) used in the aqueous coating material of the present invention, when the total amount of the monomers at the time of polymerization is 100% by mass, is defined as ethylenically unsaturated carboxylic acid monomer (d). Must be contained in the range of 0.1 to 10% by mass, and preferably in the range of 1 to 8% by mass.

Ethylenically unsaturated carboxylic acid monomer (d)
Is contained in an amount of 0.1% by mass or more, whereby the dispersion stability of the aqueous coating material is improved, and when the aqueous coating material of the present invention is colored by adding a pigment, it is possible to avoid the problem that aggregates are generated. it can. In addition, by keeping the content of the ethylenically unsaturated carboxylic acid monomer at 10% by mass or less, the dispersion stability is maintained without lowering the water resistance of a film obtained by using this aqueous coating material. Can be.

The ethylenically unsaturated carboxylic acid monomer (d) used in the aqueous coating material of the present invention includes (meth) acrylic acid, itaconic acid, citraconic acid, maleic acid, monomethyl maleate and monobutyl maleate. , Monomethyl itaconate, monobutyl itaconate, vinylbenzoic acid, monohydroxyethyl oxalate (meth) acrylate, and the like.

Further, as the ethylenically unsaturated carboxylic acid monomer unit (d), a compound represented by the following general formula (II) is preferable. By using an ethylenically unsaturated carboxylic acid monomer having such a structure, excellent adhesion to a metal substrate or the like can be provided.

CH ₂ ＣＲCR ² —COO—R ³ —OC (O) —R ⁴ —COOH (II) (wherein R ² is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R ³ is A linear or branched alkylene group having 1 to 12 carbon atoms, and R ⁴ represents a linear or branched hydrocarbon substituent having 2 to 15 carbon atoms or a hydrocarbon substituent having a cyclic structure.) General formula (II) Examples of the ethylenically unsaturated carboxylic acid monomer (d) represented by the formula: monohydroxyethyl (meth) acrylate tetrahydrophthalate, monohydroxypropyl (meth) acrylate tetrahydrophthalate, 5-methyl-1,2-cyclohexane Monohydroxyethyl (meth) acrylate dicarboxylate, monohydroxyethyl (meth) acrylate phthalate, monohydroxypropyl (meth) acrylate phthalate, Ynoic acid mono-hydroxypropyl (meth) acrylate, mono-hydroxyethyl maleate (meth) acrylate,
And monohydroxybutyl tetrahydrophthalate (meth) acrylate.

Other ethylenically unsaturated monomers (e)
Can be appropriately selected and used as needed, and the amount of use (mass percentage) depends on the amount of the monomers (a) to (d).
Is used in such an amount that the sum of the above and the mass percentage becomes 100% by mass. Further, the copolymer (A) of the aqueous coating material of the present invention comprises:
Although it may be obtained by polymerizing only the monomers (a), (b), (c) and (d), the monomer (e) may be used in an amount of 0.1 to 94.7.
It is preferable to use it in the range of mass% because the appearance and flexibility of the obtained film are improved. More preferably,
It is in the range of 15 to 80% by mass.

Other ethylenically unsaturated monomers (e) include methyl (meth) acrylate and ethyl (meth)
Acrylate, n-butyl (meth) acrylate, i-
Butyl (meth) acrylate, cyclohexyl (meth)
(Meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms, such as acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol di (meth) acrylate, butylene Glycol di (meth) acrylates such as glycol di (meth) acrylate, alkylamino (meth) acrylates such as dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate methyl chloride salt,
Allyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycidyl (meth) acrylate, aromatic vinyl compounds such as styrene, α-methylstyrene, p-methylstyrene, vinyl acetate, vinyl propionate, (meth) acrylonitrile Benzyl (meth) acrylate, acrylamide, diacetone acrylamide and the like. These may be 1 if necessary.
More than one kind can be appropriately selected and used.

Further, as another ethylenically unsaturated monomer (e), when the total amount of the monomers during polymerization is 100% by mass, the amount of the ethylenically unsaturated monomer containing a carbonyl group or aldehyde group is 0%. The aqueous coating material is obtained by mixing an organic hydrazine derivative having at least two hydrazino groups in a molecule with an aqueous resin dispersion containing 0.5 to 10% by mass and containing the copolymer (A). It is possible to exhibit more excellent strength, weather resistance and stain resistance of the coating film.

The mole number of the carbonyl group or aldehyde group contained in the copolymer (A) is (X), and the mole number of the hydrazino residue in the aqueous coating material of the present invention is (Y).
, The ratio is 0.1 <(X) / (Y) <10
0.8 <(X) / (Y)
It is more preferable to be within the range of <2. This is (X)
If / (Y) is 0.1 or less, the organic hydrazine compound which does not cause a crosslinking reaction with a carbonyl group or an aldehyde group is present in a large excess, so that the water resistance is lowered. If (X) / (Y) is 10 or more, crosslinking is not carried out. This is because the effect of crosslinking cannot be obtained due to the low degree.

Assuming that the total amount of the monomers at the time of polymerization is 100% by mass, at least 0.5% by mass of a carbonyl group or aldehyde group-containing ethylenically unsaturated monomer is contained, and (X) /
By blending the organic hydrazine compound within the preferred range of (Y), the strength, weather resistance, stain resistance, and solvent resistance of the coating film are improved, and the content is adjusted to 10% by mass or less,
By blending the organic hydrazine compound within the preferred range of (X) / (Y), excellent strength, weather resistance and stain resistance can be obtained without impairing the polymerization stability of the copolymer (A) and the water resistance of the coating film. Properties and solvent resistance. Preferably it is in the range of 1 to 8% by mass.

Examples of the ethylenically unsaturated monomer containing a carbonyl group or an aldehyde group include acrolein, diacetone acrylamide, formylstyrene, vinyl alkyl ketone, etc., preferably, vinyl methyl ketone having 4 to 7 carbon atoms, vinyl In addition to ethyl ketone, vinyl isobutyl ketone, (meth) acryloxyalkylpropanal, (meth) acrylamide, pivalinaldehyde, diacetone (meth) acrylate, acetonitrile acrylate, acetoacetoxyethyl (meth) acrylate, and the like. Acrolein, diacetone acrylamide and vinyl methyl ketone are particularly preferred. One or more of these can be appropriately selected and used as needed.

As the organic hydrazine derivative having at least two hydrazino groups in the molecule blended in the aqueous resin dispersion containing the copolymer (A), a dicarboxylic acid hydrazide having 2 to 10 carbon atoms is preferable. 4-6 dicarboxylic acid hydrazides are more preferred. Examples of the dicarboxylic acid hydrazide having 2 to 4 carbon atoms include aliphatic water-soluble hydrazines such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, and butylene-1,4-dihydrazine. Examples of the dicarboxylic acid hydrazide having 4 to 6 carbon atoms include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide,
Isophthalic dihydrazide and itaconic dihydrazide. Among them, adipic dihydrazide, sebacic dihydrazide, isophthalic dihydrazide and succinic dihydrazide are particularly preferable. One or more of these can be appropriately selected and used as needed.

The copolymer (A) constituting the water-based coating material of the present invention has a calculated glass transition temperature (Tg) obtained from the formula of Fox in view of the non-adhesiveness and stain resistance of the obtained coating film. Is preferably −10 ° C. or higher,
0 ° C. or higher is more preferable. Further, the temperature is preferably 70 ° C. or less, more preferably 60 ° C. or less, from the viewpoint of crack resistance in a thermal cycle test.

The Fox equation is the following relational equation regarding the glass transition temperature (° C.) of the copolymer. 1 / (273 + Tg) = Σ (Wi / (273 + Tg)
i)) (wherein, Wi represents the mass fraction of the monomer i, and Tgi represents the Tg (° C.) of the homopolymer of the monomer i.) The copolymer (A) constituting the aqueous coating material of the present invention is as described above. It can be obtained by polymerizing the monomers (a) to (e) by a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method, and the copolymer (A) is in the form of an emulsion by emulsion polymerization. Is preferred from the viewpoint of various physical properties such as storage stability of the aqueous coating material, hardness of the coating, weather resistance and stain resistance.

In order to obtain the emulsion used in the present invention by emulsion polymerization, a method in which a monomer mixture is fed into a polymerization system in the presence of a surfactant and polymerization is carried out with a water-soluble initiator, A method such as a method in which polymerization is carried out with a redox initiator obtained by combining a peroxide and a reducing agent such as sodium thiosulfate can be used.

The aqueous coating material of the present invention comprises a copolymer (A) 1
It is preferable that the surfactant is contained in the range of 0.1 to 10 parts by mass with respect to 00 parts by mass. The presence of the surfactant in an amount of 0.1 part by mass or more improves the storage stability of the aqueous coating material, and also improves the stability during polymerization when emulsion polymerization is performed in the presence of the surfactant. Further, when the amount of the surfactant is 10 parts by mass or less, stability at the time of compounding into a paint, stability over time, and the like can be maintained without impairing water resistance. More preferably, it is in the range of 0.5 to 6 parts by mass.

Examples of the surfactant used in the present invention include various anionic, cationic or nonionic surfactants, and furthermore, a polymer emulsifier. The surfactant component contains an ethylenically unsaturated bond. A so-called reactive emulsifier having the following formula can also be used. The method of supplying the monomer into the polymerization system may be any of various methods, and is not particularly limited.

The emulsion obtained by the emulsion polymerization method can be prepared by adjusting the pH of the system after the polymerization by adding a basic compound to a neutral range to a weak alkalinity, that is, a pH range of about 6.5 to 10.0. Stability can be improved.

Examples of the basic compound to be added include ammonia, triethylamine, propylamine, dibutylamine, amylamine, 1-aminooctane, 2-dimethylaminoethanol, ethylaminoethanol, 2-diethylaminoethanol, and 1-amino-2-amine. Propanol, 2-amino-1-propanol, 3-amino-1-
Examples thereof include propanol, 1-dimethylamino-2-propanol, 3-dimethylamino-1-propanol, 2-propylaminoethanol, ethoxypropylamine, aminobenzyl alcohol, morpholine, sodium hydroxide, and potassium hydroxide.

When adjusting the molecular weight of the copolymer (A), n-dodecyl mercaptan, t
-It can be adjusted by using a chain transfer agent such as dodecyl mercaptan or α-methylstyrene dimer.

The aqueous coating material of the present invention usually has a solid content of 20%.
It is used in the range of ８０80% by mass. In the aqueous coating material of the present invention, various pigments, an antifoaming agent, a pigment dispersant, a slip agent, a preservative, a plasticizer, and the like are added and used in order to express high performance for a coating material. Can also.

The coating method for forming a coating on the surface of various materials using the aqueous coating material of the present invention includes spray coating, roller coating, bar coating, air knife coating, brush coating, and dipping. And other various methods can be appropriately selected and used.

When the aqueous coating material of the present invention is used as a coating material, a sufficiently formed film can be obtained by drying at a temperature in the range of room temperature to about 120 ° C. for about 1 minute to about 1 week.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. The weather resistance, stain resistance, adhesion, water resistance, and storage stability were evaluated by the following methods.

Preparation of water-based paint for evaluation (Preparation of clear paint) Kyowanol M (trade name, manufactured by Kyowa Hakko Co., Ltd.) as a plasticizer was added to the water-based coating material (emulsion) so that the minimum film-forming temperature was 10 ° C. Appropriate amount (Example: In Example 6, 10 wt.
%), RHEOLATE 350 (trade name,
RHEOX) (3 wt% (based on solid content)), and after sufficiently stirring, 100 seconds to 120 seconds using a Ford cup # 4.
It was adjusted by adding deionized water to about 2 seconds. After the adjustment, filtration was performed using a 300 mesh nylon gauze to prepare an aqueous clear paint for evaluation. (Preparation of white enamel paint) TYPAKE R-930 (trade name, manufactured by Ishihara Sangyo Co., Ltd., sulfuric acid method titanium oxide)
3 g, OROTAN SG-1 (trade name, manufactured by Rohm & Haas Co., Ltd., pigment dispersant) 2.1 g, Surfynol DF
-58 (trade name, manufactured by Air Products, defoamer) 0.0
8 g, propylene glycol 29.4 g, deionized water 3
After sufficiently mixing 4.3 g and 1.8 g of a 28% aqueous ammonia solution, glass beads were added and the pigment was dispersed with a high-speed disperser for 30 minutes, and then the glass beads were filtered off with a 300 mesh nylon gauze. Mill base.

Next, an aqueous coating material (emulsion) 100
g (solid content: 45% by mass), 45 g of the above mill base for evaluation, and Kyowanol M having a minimum film-forming temperature of 1
A suitable amount (eg, 4.5 in Example 6) so as to be 0 ° C.
g), 1.5 g of RHEOLATE 350 is added in order,
After sufficiently stirring, 100 seconds with Ford Cup # 4
It was adjusted by adding deionized water to about 140 seconds.

Thereafter, filtration was again performed using a 300 mesh nylon gauze to produce an aqueous white enamel paint for evaluation. (1) Weather resistance test A white enamel water-based paint for evaluation was applied to a zinc phosphate-treated steel sheet of 150 mm × 70 mm using a bar coater # 40.
Drying was performed for 1 week in an environment at a temperature of 65 ° C. × 65% Rh to prepare a coated plate for a weather resistance test. The dry film thickness was 20 μm in all the examples and comparative examples.

After a polyester tape was stuck to the painted surface of the painted plate to prevent water droplets and the like during the weather resistance test from adhering to places other than the painted surface, the irradiance was measured.
30W / m ² , irradiation temperature 70 ° C, wet temperature 50
℃ 1 cycle 12 hours (irradiation time 8 hours, wet time 4 hours) set the Suga Test Instruments Co., Ltd. due panel light control weather meter DPWL-5 type painted plate, put 2000 hours after 60 hours候 Weather resistance test was performed using the gloss retention as an index. In Comparative Example 8, cracks occurred on the painted surface after the weather resistance test. (2) Stain resistance test A painted board for a weather resistance test was mounted on an exposure table outdoors (Higashi-ku, Nagoya City) so that the south face was at 45 degrees, and an exposure test was performed for 6 months in summer. The difference between the L value and the L value of the coated plate after exposure was ΔL, which was used as an index of contamination, and evaluated according to the following criteria. A: ΔL value is less than 5.0 O +: ΔL value is 5.0 or more and less than 7.5 O: ΔL value is 7.5 or more and less than 10.0 O-: ΔL value is 10.0 or more and less than 12.5 Δ: ΔL value is 12.5 or more and less than 15.0 ×: ΔL value is 15.0 or more (3) Adhesion test (Adhesion test with fluorine-based coating film) Mortar plate coated with base adjustment material (JIS A) 6910) based on the above-mentioned water-based clear paint for evaluation, after applying the water-based clear paint for evaluation to a dry film thickness of 20 μm (intermediate coating) and drying at 20 ° C. × 65% Rh for 1 day. Lumiflon FE-4000 (produced by Asahi Glass Co., Ltd., fluorinated emulsion) made into a paint by prescription is applied so that the dry film thickness becomes 20 μm (overcoat), and dried for 3 days in an environment of 20 ° C. × 65% Rh. A coated plate for evaluation was prepared.

[0050] Only 100 square grids of 2 mm square were formed with a cutter knife only on the top coating film of the coated plate for evaluation, and then a Cellotape (registered trademark) peel test was carried out three times at the same place, and a peel test was carried out three times. Squares that did not peel off after the operation were counted. The numerical value of the adhesion evaluation in Table 2 is the number of the masses that have not been peeled off. (Adhesion test with cold-rolled steel sheet) Sodium nitrite was added as a rust inhibitor in an amount of 2% with respect to the above-mentioned water-based clear paint for evaluation, and the dry film thickness of the degreased cold-rolled steel sheet was 20 µm
Paint in an environment of 20 ° C x 65% Rh.
Drying was performed for a week to prepare a coated plate for evaluation.

A 100 mm square of 2 mm square was formed on the coating film of this evaluation coated plate with a cutter knife, and then the adhesive tape peeling test was performed three times at the same location. The missing cells were counted. The numerical value of the adhesion evaluation in Table 2 is the number of the masses that have not been peeled off. (4) Water resistance test Mortar board (JIS A 691) coated with base adjustment material
0) based on the water-based clear paint for evaluation having a dry film thickness of 20.
It was coated so as to have a thickness of μm and dried for one week in an environment of 20 ° C. × 65% Rh to prepare a coated plate for evaluation.

The coated plate for evaluation was immersed in pure water at 40 ° C. for 24 hours, and the superiority was judged based on the following criteria based on the state of the gloss immediately after lifting. ◎: There was no gloss, and the initial appearance was maintained. ：: Some gloss was observed, but the gloss retention of 60 degrees was 90.
% Or more −-: Slightly glossy, but 60-degree gloss retention is 80%
%: Practicality at% or more △: Partially glossy ×: Remarkable glossiness on the entire surface (5) Storage stability test Viscosity of aqueous coating material (emulsion) left at room temperature for 1 month after storage at 40 ° C. for 1 week , PH measurement and state were observed and evaluated according to the following criteria. ◎: No aggregate was generated, the change in pH was less than 0.5 and the change in viscosity was less than 5% of the initial value. ○: No aggregate was generated, the change in pH was less than 1.0, and The change in viscosity is less than 10% of the initial value. Δ: No agglomerate is generated, but the change in pH and viscosity is larger than the above standard (○). X: Agglomerate, gelation, etc. are generated, and the coating material is used. (6) Comprehensive evaluation The comprehensive evaluation was performed according to the following criteria. ：: Gloss retention of 90% or more after weather resistance test, stain resistance ◎
Above, adhesion to a film formed with a fluorine-based paint of 90 or more, adhesion to a cold-rolled steel sheet of 90 or more, water resistance and storage stability ○ or more ○ +: gloss retention after weather resistance test of 80% or more , Stain resistance ＋+ or more, adhesion to a film formed of a fluorine-based paint 9
0 or more, adhesion to cold-rolled steel sheet 90 or more, water resistance and storage stability ○ or more ○: gloss retention 70% or more after weather resistance test, stain resistance ○ or more, coating formed of fluorine-based paint Adhesion 90
Above, adhesion to cold-rolled steel sheet of 90 or more, water resistance and storage stability of ○ or more −: gloss retention after weather resistance test of 60% or more, stain resistance of −- or more, formed of fluorine-based paint Adhesion with coating 9
0 or more, adhesion to cold rolled steel sheet 90 or more, water resistance
Above, storage stability 以上 or more △: Gloss retention after weather resistance test of 60% or more, stain resistance of △ or more, adhesion to a film formed of a fluorine-based paint 80
Above, adhesion to cold-rolled steel sheet of 80 or more, water resistance of △ or more, storage stability of △ or more, which has a problem in practical use. ×: gloss retention after weathering test, stain resistance, adhesion ,
Any one of the items of water resistance and storage stability was lower than the reference value shown in the above-mentioned comprehensive evaluation (1). The internal temperature was raised to 60 ° C. Thereafter, 100 parts by mass of the monomer mixture having the composition shown in Table 1 below, a surfactant, and deionized water were sufficiently mixed to prepare a pre-emulsion in a uniform emulsified state (hereinafter abbreviated as “PE liquid”). .

5 parts by weight of the prepared PE solution was put into a polymerization vessel, the internal temperature of the polymerization vessel was raised to 75 ° C., and when the internal temperature was stabilized, 0.2 parts by weight of sodium persulfate was added to deionized water. Dissolved in 5 parts by mass and sodium bisulfite 0.1%
One part by mass dissolved in 5 parts by mass of deionized water was added and left for 1 hour.

After 1 hour, the remainder of the PE solution and 0.2 parts by weight of sodium persulfate dissolved in 10 parts by weight of deionized water, and 0.1 parts by weight of sodium bisulfite were added to 10 parts by weight of deionized water. The melted solution was cooled to 75 ° C.
The mixture was added dropwise to the polymerization vessel over 3 hours while maintaining the temperature at 0 ° C. After completion of the addition, the internal temperature was maintained at 80 ° C for 2 hours to complete the reaction.

After the reaction was completed, cooling was carried out, and a 28% aqueous ammonia solution was added so that the pH of the emulsion was 7.5 to 10, to obtain an aqueous coating material.

The results of the weather resistance test, the stain resistance test, the adhesion test, the water resistance test, and the storage stability test of the obtained aqueous coating material were as shown in Table 3 below.

Examples 2 to 7 In the same manner as in Example 1, aqueous coating materials having the monomer compositions shown in Table 1 below were prepared. The results of the weather resistance test, the stain resistance test, the adhesion test, the water resistance test, and the storage stability test for these were as shown in Table 3 below.

Comparative Examples 1 to 7 In the same manner as in Example 1, aqueous coating materials having the monomer compositions shown in Table 2 below were prepared. However, in Comparative Example 7, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) -sebacate (polymerizable unsaturated diamine) was added to the solid content of the emulsion having the monomer composition shown in Table 2. 2% by mass of hindered amine light stabilizer containing no heavy bond)
Was added to form an aqueous coating material.

The results of the weather resistance test, the stain resistance test, the adhesion test, the water resistance test, and the storage stability test are shown in Table 4 below.

As is clear from Table 3, the water-based coating material of the present invention was excellent in water resistance and storage stability, and was also excellent in weather resistance, stain resistance, adhesion to a fluorine-based film and a metal plate. On the other hand, those that do not satisfy the requirements of the present invention do not satisfy weather resistance, stain resistance, adhesion, and water resistance performance in a highly balanced manner, and lack various stability required as an emulsion. In some cases, agglomerates are generated at the stage where a plasticizer or the like is blended.

[0061]

【table 1】 ([CO]: mole number of carbonyl group, [NHNH2]:
Number of moles of hydrazino residue)

[0062]

[Table 2] t-BMA: tertiary butyl methacrylate t-BA: tertiary butyl acrylate ADK STAB LA-82: 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) LA-87: 2,2,6,6-tetramethyl-4-piperidyl methacrylate (trade name, manufactured by Asahi Denka Kogyo KK) 2-HEMA: 2-hydroxyethyl methacrylate Praxel FM-3: lactone-modified hydroxyethyl methacrylate (Trade name, manufactured by Daicel Chemical Industries, Ltd.) Blemmer 70PEP350B: hydroxy (polyethylene glycol-polypropylene glycol) monomethacrylate (trade name, manufactured by NOF Corporation) MAA: methacrylic acid HH: monohydroxyethyl tetrahydrophthalate Methacrylate n-BMA: normal butyl methacrylate 2-EHA: 2-ethylhexyl acrylate CHMA: cyclohexyl methacrylate MMA: methyl methacrylate DAAM: diacetone acrylamide ADH: adipic acid dihydrazide ABEX 23-S: trade name, anionic emulsifier manufactured by Rhodia Co., Ltd. Sannole NP-2030: Trade name, Lion Corporation
Anionic emulsifier manufactured by Adekalia Soap SE-10N: trade name, reactive anionic emulsifier manufactured by Asahi Denka Co., Ltd. Additive-1: bis (1,2,2,6,6-pentamethyl-4-piperidinyl) -sebacate

[0063]

[Table 3]

[0064]

[Table 4]

[0065]

According to the present invention, there is no bleed-out from the coating film, and it has excellent weather resistance and stain resistance.
An aqueous coating having good adhesion to a coating formed by various paints such as acrylic, silicone, and fluorine can be provided, and is extremely useful in industry.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaaki Ito 4-160 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi F-term in the Mitsubishi Rayon Co., Ltd. Product Development Laboratory (reference) 4J038 CC091 CE051 CG011 CG121 CG131 CG141 CG171 CG191 CH031 CH051 CH131 CH151 CH181 CH201 CH221 GA06 GA08 GA13 JB17 MA08 NA03 NA05 NA12 PB05 PC01 PC03 PC04 PC08 4J100 AB02T AB03T AB04T AB07T AF06T AF10T AG02T AG04T AG08S AJ02S AJ08S AJ09S AL03T AL03T AL08 AL08 AL08T AL08T AL08T AL08T AL08T AL08T AL08T AL08T AL08T AL08T BA03R BA05T BA08R BA09R BA13T BA14T BA15S BA16S BA17T BA27T BA31T BA40Q BC04R BC04S BC04T BC43S BC43T BC65Q CA03 CA06

Claims (5)

[Claims] 1. An ethylenically unsaturated monomer (a) represented by the following general formula (I): 5 to 80% by mass, and CH ₂ ＣＲCR ¹ —COO—C (CH ₃ ) ₃ (I) ( In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms.) 0.1 to 10% by mass of an ethylenically unsaturated monomer (b) having a piperidyl group and an ethylenically unsaturated monomer having a hydroxyl group 0.1 to 25% by mass of a saturated monomer (c), 0.1 to 10% by mass of an ethylenically unsaturated carboxylic acid monomer (d), and 0 of other ethylenically unsaturated monomers (e) ~ 9
An aqueous solution characterized by containing a copolymer (A) obtained by polymerizing 4.7% by mass (the total of the mass percentages of the monomers (a) to (e) is 100% by mass). Coating material. 2. The aqueous coating material according to claim 1, wherein (c) is a hydroxyl-terminated polyalkylene glycol mono (meth) acrylate. 3. The method according to claim 1, wherein (e) is a carbonyl group or aldehyde group-containing ethylenically unsaturated monomer in an amount of 0.5 to 1;
An organic hydrazine derivative having at least two hydrazino groups in a molecule is blended with an aqueous resin dispersion containing 0% by mass and containing a copolymer (A). An aqueous coating material as described in the above. 4. The method according to claim 1, wherein (d) is a compound represented by the following general formula (II).
An aqueous coating material as described in the above. CH ₂ ＣＲCR ² —COO—R ³ —OC (O) —R ⁴ —COOH (II) (wherein R ² is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R ³ is a carbon atom having 1 carbon atom. A straight-chain or branched alkylene group having 1 to 12 carbon atoms, and R ⁴ represents a straight-chain or branched hydrocarbon substituent having 2 to 15 carbon atoms or a hydrocarbon substituent having a cyclic structure.) 5. The surfactant according to claim 1, wherein the surfactant is contained in an amount of 0.1 to 10 parts by mass based on 100 parts by mass of the copolymer (A). Aqueous coating material.