JP2016113535A - Coating composition and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition capable of forming a cured product which can exhibit and maintain weather resistance and low staining properties over a long period of time in a high temperature and high humidity area and to provide a coated article having the cured film on the surface.SOLUTION: There is provided a coating film which comprises: a fluorine-containing copolymer (A) having a specific unit, a number average molecular weight of 10000 to 100000, a hydroxyl value of 150 to 500 mgKOH/g and an alternating copolymerization ratio of 95% or more; one or both of the following fluorine-containing copolymer (B-1) and polyvinylidene fluoride (B-2); and a hydrolyzable silane compound. The fluorine-containing copolymer (B-1) has a specific unit, a number average molecular weight of 5000 to 100000, a hydroxyl value of 1 to 120 mgKOH/g and an alternating copolymerization ratio of 90% or more. In addition, there is provided a coated article which has a cured film formed using the coating composition on the surface of a substrate.SELECTED DRAWING: None

Description

  The present invention relates to a coating composition and a coated article.

In recent years, rain streak contamination on the outer wall of an outdoor building has become a problem, and therefore a coating composition capable of forming a cured film having excellent contamination resistance has been developed.
As such a coating composition, for example, a compound containing a specific organosilicate compound or a silicate condensate as a low-contamination agent in addition to a hydroxyl group-containing resin can be mentioned (Patent Document 1).

JP2013-159622A

However, according to the knowledge of the present inventors, the coating composition described in Patent Document 1 does not have sufficient initial low-contamination property, and in a high-temperature and high-humidity region, the cured film is rapidly deteriorated and low-contamination. It is difficult to maintain performance over a long period of time.
Accordingly, the present invention provides a coating composition that can form a cured film capable of expressing and maintaining excellent weather resistance and low contamination over a long period of time in a high-temperature and high-humidity region, and a coated article having the cured film on the surface. Objective.

The present invention has the following aspects [1] to [5].
[1] It has a unit represented by the following formula (1) and a unit represented by the following formula (2), has a number average molecular weight of 10,000 to 100,000, and a hydroxyl value of 150 to 500 mgKOH. / G and the alternating copolymerization ratio is 95% or more, and any one of the fluorine-containing copolymer (A), the following fluorine-containing copolymer (B-1) and the polyvinylidene fluoride (B-2) Or the composition for coatings containing both and a hydrolysable silane compound (C).

[In the formula (1), X and Y are each independently H, F, CF ₃ or Cl. ]
Fluorine-containing copolymer (B-1): Unit based on fluoroolefin (b1), unit based on monomer having crosslinkable group (b2), unit based on vinyl ether compound having no crosslinkable group, and crosslink One or both of units based on a vinyl ester compound having no functional group (b3), a number average molecular weight of 5,000 to 100,000, a hydroxyl value of 1 to 120 mgKOH / g, The polymerization ratio is 90% or more.
[2] The coating composition according to [1], further comprising at least one curing agent (D) selected from the group consisting of an isocyanate curing agent, a blocked isocyanate curing agent, and an amine curing agent.

[3] A coated article having a cured film formed on the surface of a substrate using the coating composition according to [1] or [2].
[4] The coated article according to [3], wherein a water contact angle on the surface of the cured film is 1 to 55 °.
[5] The base material according to [3] or [4], wherein the base material is formed of at least one selected from the group consisting of metal, stone, glass, resin, rubber, wood, and a composite material thereof. Painted article.

  According to the present invention, it is possible to provide a coating composition capable of forming a cured film capable of expressing and maintaining excellent weather resistance and low contamination over a long period of time in a hot and humid area, and a coated article having the cured film on the surface. Can do.

In the present invention, the “unit” means a portion derived from a monomer that exists in the polymer and constitutes the polymer. Moreover, what unitally converted the structure of a unit after polymer formation is also called a unit.
The “crosslinkable group” means a group capable of directly cross-linking copolymer molecules or a group capable of forming a cross-linked structure between copolymer molecules by reacting with a cross-linking agent.
“Fluorine-containing resin” means a polymer compound having a fluorine atom in the molecule.
“Non-fluorinated resin” means a polymer compound having no fluorine atom in the molecule.
The “coating film” means a film formed by applying a paint on the surface of a base material and before being cured.
The “cured film” means a film obtained by curing the coating film.

[Coating composition]
The coating composition of the present invention comprises a fluorinated copolymer (A) (hereinafter also referred to as “copolymer (A)”), a fluorinated copolymer (B-1) (hereinafter referred to as “copolymer”). (B-1) ") and polyvinylidene fluoride (B-2) (hereinafter also referred to as" PVDF (B-2) ") or both (hereinafter referred to as" copolymer (B ) ") And hydrolyzable silane compound (C).
The coating composition of the present invention comprises a curing agent (D), a pigment (E), a curing catalyst (F), another resin (G), an organic solvent, a medium (H) such as water, and the like as necessary. Other components (I) and the like may be contained.

  The coating composition of the present invention is obtained by reacting the hydroxyl groups of the fluorinated copolymer (A) to form a crosslinked structure, or with the hydroxyl group and an optional blending agent (D). Can be cured by forming a crosslinked structure by forming a crosslinked structure.

  The coating composition of the present invention may be a solvent-based coating composition, a water-based coating composition, or a powder coating composition.

(Copolymer (A))
The copolymer (A) includes a unit represented by the following formula (1) (hereinafter also referred to as “unit (a1)”) and a unit represented by the following formula (2) (hereinafter referred to as “unit (a2)”. The number average molecular weight is 10,000 to 100,000, the hydroxyl value is 150 to 500 mgKOH / g, and the alternating copolymerization ratio is 95% or more.

In formula (1), X and Y are each independently H, F, CF ₃ or Cl.
As the unit (a1), X is F, and Y is F or Cl in terms of excellent resistance to color floating and color separation (hereinafter also referred to as “color floating / color separation property”). A certain unit is preferable, and a unit in which the Y is F is particularly preferable.

  The number average molecular weight (Mn) of the copolymer (A) is 10,000 to 100,000. The number average molecular weight (Mn) of the copolymer (A) is preferably 10,000 to 90,000, more preferably 10,000 to 80,000, and particularly preferably 10,000 to 75,000. When the number average molecular weight is not less than the lower limit of the above range, the entanglement between the molecular chains is sufficiently secured and a tough cured film can be formed. If it is not more than the upper limit value, it is excellent in solubility in an organic solvent, fluidity during molding, and the like, and a homogeneous cured film can be formed.

1-5 are preferable and, as for molecular weight distribution (mass average molecular weight (Mw) / Mn) of a copolymer (A), 1-3 are especially preferable. When the molecular weight distribution is not more than the upper limit of the above range, the gel content is small and a uniform cured film can be obtained.
The number average molecular weight (Mn), mass average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the copolymer (A) are measured by size exclusion chromatography (GPC) using polystyrene standards.

The hydroxyl value of the copolymer (A) is 150 to 500 mgKOH / g. The hydroxyl value of the copolymer (A) is preferably 150 to 450 mgKOH / g. When the hydroxyl value of the copolymer (A) is 150 mgKOH / g or more, it is excellent in adhesion to a substrate, curability, color resistance and color separation. When the hydroxyl value of the copolymer (A) is not more than the upper limit of the above range, since the curing speed and the curing amount are appropriate, a uniform cured film can be formed.
The hydroxyl value of the copolymer (A) can be adjusted by the content of the unit (a2), the content of units other than the unit (a1) and the unit (a2), and the like.
The hydroxyl value of the copolymer (A) is calculated by nuclear magnetic resonance, or by acetylating the hydroxyl group in the copolymer (A) with acetic anhydride and titrating excess acetic acid with a potassium hydroxide solution. Can be measured.

The alternating copolymerization ratio of the unit (a1) and the unit (a2) in the copolymer (A) is 95% or more. When the alternating copolymerization ratio is 95% or more, the cured film is excellent in weather resistance, low contamination, color resistance and color separation for a long period of time.
The alternating copolymerization ratio in the copolymer (A) is the ratio of the number of combinations in which different units are adjacent to the total number of combinations of two adjacent units. For example, when the copolymer (A) is a copolymer represented by 121221212121212121212 (where 1 is a unit (a1) and 2 is a unit (a2)), a combination of two adjacent units Since the number is 20 and the number of combinations in which different units are adjacent is 19, the alternating copolymerization rate is 95%.
The alternating copolymerization ratio can be calculated by the Monte Carlo method from the polymerization reactivity ratio of a plurality of monomers used for the synthesis of the copolymer. The alternating copolymerization ratio can be adjusted by a combination of monomers. The lower and closer the polymerization reactivity of each monomer, the higher the alternating copolymerization ratio.

  In the copolymer (A), the content of the unit (a1) is preferably 20 to 80 mol%, more preferably 30 to 70 mol%, based on the total of all units constituting the copolymer (A). 40 to 60 mol% is particularly preferable. When the content of the unit (a1) is not less than the lower limit of the above range, the fluorine atom content in the copolymer (A) is increased, and the weather resistance is excellent. It is excellent in the solubility to a solvent and the adhesiveness to the base material of a cured film as it is below an upper limit.

  In the copolymer (A), the content of the unit (a2) is preferably 80 to 20 mol%, more preferably 70 to 30 mol%, based on the total of all units constituting the copolymer (A). 60 to 40 mol% is particularly preferable. If the content of the unit (a2) is not less than the lower limit of the above range, the amount of hydroxyl groups in the copolymer (A) increases, so that adhesion to the substrate, curability, color resistance and color separation / color separation Excellent in properties. When it is at most the upper limit value, the curing rate and the curing amount are appropriate, so that a uniform cured film can be formed.

In the copolymer (A), the molar ratio of the unit (a1) to the unit (a2) (unit (a1) / unit (a2)) is preferably 40/60 to 60/40, and 45/55 to 55 / 45 is more preferable, and 50/50 is particularly preferable.
The smaller the difference between the content of the unit (a1) and the content of the unit (a2), the better the color resistance, color separation, weather resistance, etc.

The copolymer (A) may further have other units other than the unit (a1) and the unit (a2) as long as the effects of the present invention are not impaired.
Examples of other units include units based on the following monomers. These monomers may be used individually by 1 type, or may use 2 or more types together.
Hydroxyethyl allyl ether, ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, ethylene, propylene, vinyl acetate, allyl acetate, vinyl propionate, maleic anhydride, itaconic anhydride and the like.

  In the copolymer (A), the content of other units is preferably from 0.01 to 10 mol%, preferably from 0.03 to 5 mol%, based on the total of all units constituting the copolymer (A). More preferably, 0.05-3 mol% is further more preferable. When the content of other units is not less than the lower limit of the above range, the adhesion to the substrate is excellent. When it is at most the upper limit value, the alternating copolymerization ratio can be adjusted to 95% or more.

  The copolymer (A) can be produced by a known method. For example, a copolymer having an alternating copolymerization ratio of unit (a1) and unit (a2) of 95% or more can be produced according to the method described in International Publication No. 2012/165503, International Publication No. 2013/051668, or the like. If the desired fluorine-containing copolymer is commercially available, it may be used as the copolymer (A).

  A copolymer (A) may be used individually by 1 type, or may use 2 or more types together.

(Copolymer (B))
The coating composition contains one or both of a copolymer (B-1) and PVDF (B-2) as the copolymer (B).

  The copolymer (B-1) includes a unit (b1) based on a fluoroolefin (hereinafter also referred to as “unit (b1)”) and a unit (b2) based on a monomer having a crosslinkable group (hereinafter referred to as “unit”). (Also referred to as “unit (b2)”) and / or a unit based on a vinyl ether compound having no crosslinkable group and a unit based on a vinyl ester compound having no crosslinkable group (b3) (hereinafter referred to as “unit”) (B3) "), a number average molecular weight of 5,000 to 100,000, a hydroxyl value of 1 to 120 mgKOH / g, and an alternating copolymerization ratio of 90% or more.

Examples of the fluoroolefin forming the unit (b1) include tetrafluoroethylene (hereinafter also referred to as “TFE”), chlorotrifluoroethylene (hereinafter also referred to as “CTFE”), trifluoroethylene, hexafluoropropylene, fluorine. And vinylidene chloride and vinyl fluoride. Of these, TFE and CTFE are preferable.
The fluoroolefin which forms a unit (b1) may be used individually by 1 type, or may use 2 or more types together.

  Examples of the crosslinkable group that the unit (b2) has include a hydroxyl group, a carboxy group, an amino group, an epoxy group, an alkoxysilyl group, and an isocyanate group.

Monomers that form the hydroxyl group-containing unit (b2) include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, and cyclohexane dimethanol monovinyl ether; ethylene such as diethylene glycol monovinyl ether and triethylene glycol monovinyl ether. Glycol monovinyl ethers; hydroxyalkyl allyl ethers such as hydroxyethyl allyl ether and hydroxybutyl allyl ether; hydroxyalkyl vinyl esters such as hydroxyethyl carboxylic acid vinyl ester and hydroxybutyl carboxylic acid vinyl ester; hydroxyethyl carboxylic acid allyl ester; Hydroxyalkyl carboxylic acid allys such as hydroxybutylcarboxylic acid Esters; hydroxyethyl (meth) acrylate of (meth) acrylic acid hydroxyalkyl esters.
Of these, hydroxyethyl allyl ether and hydroxybutyl vinyl ether are preferable.

As a monomer which forms the unit (b2) which has a carboxy group, (meth) acrylic acid, itaconic acid, fumaric acid, maleic acid, maleic anhydride, citraconic acid, undecylenic acid, etc. are mentioned.
Examples of the monomer forming the unit (b2) having an amino group include aminopropyl vinyl ether and diethylaminoethyl vinyl ether.
Examples of the monomer that forms the unit (b2) having an epoxy group include glycidyl vinyl ether, glycidyl carboxylic acid vinyl ester, glycidyl allyl ether, and glycidyl (meth) acrylate.
Examples of the monomer that forms the unit (b2) having an alkoxysilyl group include 3- (meth) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane, and trimethoxysilylpropyl vinyl ether. .
Examples of the monomer that forms the unit (b2) having an isocyanate group include 2-isocyanatoethyl (meth) acrylate and 1,1-bis (acryloylmethyl) ethyl isocyanate.
The monomer which forms the unit (b2) having a crosslinkable group may be used alone or in combination of two or more.

Examples of the vinyl ether compound having no crosslinkable group forming the unit (b3) include ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether and the like.
Of these, ethyl vinyl ether and cyclohexyl vinyl ether are preferable.
The vinyl ether compound which does not have a crosslinkable group which forms a unit (b3) may be used individually by 1 type, or may use 2 or more types together.

Examples of the vinyl ester compound having no crosslinkable group forming the unit (b3) include vinyl versatate, vinyl benzoate, vinyl acetate, and vinyl pivalate.
Of these, vinyl versatate, vinyl benzoate, and vinyl acetate are preferable.
The vinyl ester compound which does not have a crosslinkable group which forms a unit (b3) may be used individually by 1 type, or may use 2 or more types together.

  The number average molecular weight (Mn) of the copolymer (B-1) is 5,000 to 100,000. The number average molecular weight (Mn) of the copolymer (B-1) is preferably 6,000 to 90,000, more preferably 7,000 to 80,000, and particularly preferably 8,000 to 70,000. When the number average molecular weight is not less than the lower limit of the above range, the weather resistance, water resistance and adhesion to the substrate of the coating film are good. When it is at most the upper limit value, the compatibility with the hydrolyzable silane compound is good.

The hydroxyl value of the copolymer (B-1) is 1-120 mgKOH / g. The hydroxyl value of the copolymer (B-1) is preferably 5 to 100 mgKOH / g. When the hydroxyl value of the copolymer (B-1) is not less than the lower limit of the above range, the compatibility with the hydrolyzable silane compound is good. When the hydroxyl value of the copolymer (B-1) is less than or equal to the upper limit of the above range, the stability of the coating is difficult to decrease.
The hydroxyl value of the copolymer (B-1) is the content of the unit (b1), the content of the unit having a hydroxyl group as a crosslinkable group in the unit (b2), and the other unit (b4) described later. It can be adjusted by the content of the unit having a hydroxyl group.
The hydroxyl value of the copolymer (B-1) can be measured by the same method as the hydroxyl value of the copolymer (A).

The alternating copolymerization ratio of units (b1), units (b2) and (b3) in the copolymer (B-1) is 90% or more. When the alternating copolymerization ratio is 90% or more, the cured film is excellent in weather resistance and low contamination for a long period of time.
The alternating copolymerization ratio in the copolymer (B-1) is the ratio of the number of combinations in which different units are adjacent to the total number of combinations of two adjacent units. For example, the copolymer (B-1) is a copolymer represented by 12312331231 (where 1 represents the unit (b1), 2 represents the unit (b2), and 3 represents the unit (b3)). In this case, the number of combinations of two adjacent units is 10, and the number of combinations in which different units are adjacent is 9, so that the alternating copolymerization rate is 90%.
The alternating copolymerization ratio in the copolymer (B-1) can be calculated by the Monte Carlo method from the polymerization reactivity ratio of a plurality of monomers used for the synthesis of the copolymer. The alternating copolymerization ratio can be adjusted by a combination of monomers. The lower and closer the polymerization reactivity of each monomer, the higher the alternating copolymerization ratio.

  In the copolymer (B-1), the content of the unit (b1) is preferably 20 to 80 mol%, and preferably 30 to 70 mol based on the total of the unit (b1), the unit (b2) and the unit (b3). % Is more preferable, and 40 to 60 mol% is particularly preferable. It is excellent in the weather resistance of a coating film as content of a unit (b1) is more than the lower limit of the said range. It is excellent in compatibility with a fluoropolymer (A) as it is below an upper limit.

  In the copolymer (B-1), the content of the unit (b2) is preferably 0.1 to 50 mol% with respect to the total of the unit (b1), the unit (b2) and the unit (b3). 3-40 mol% is more preferable and 0.5-30 mol% is especially preferable. When the content of the unit (b2) is not less than the lower limit of the above range, the coating film is excellent in chemical resistance, particularly for outdoor use, The coating film deterioration with respect to acid rain can be suppressed. If it is less than or equal to the upper limit, the stability of the paint is unlikely to decrease.

  In the copolymer (B-1), the content of the unit (b3) is preferably 0.1 to 50 mol% with respect to the total of the unit (b1), the unit (b2) and the unit (b3). 3-40 mol% is more preferable and 0.5-30 mol% is especially preferable. When the content of the unit (b3) is not less than the lower limit of the above range, the adhesion with the substrate is excellent. It is excellent in the weather resistance of a coating film as it is below an upper limit.

The copolymer (B-1) further has other units (b4) other than the units (b1), (b2) and the units (b3) as long as they do not impair the effects of the present invention. May be.
Examples of the other unit (b4) include alkenyl ethers such as 1-methoxy-2-methylpropene, 1-ethoxy-2-methylpropene, and 1-methoxy-2-methylbutene; ethylene, propylene, isobutene, butene, Units based on olefins such as styrene; acrylamides such as 1-vinylimidazole, (meth) acrylamide, and N, N-dimethyl (meth) acrylamide; vinylsilanes such as vinyltrimethoxysilane and vinylmethyldiethoxysilane It is done.
Another unit (b4) may be used individually by 1 type, or may use 2 or more types together.
In the copolymer (B-1), the content of the unit (b4) is preferably 0 to 5 mol% with respect to the total of all units constituting the copolymer (B-1). The ratio of the other unit (b4) being 0 mol% means that the other unit (b4) is not included, and the lower limit when the other unit (b4) is included is more than 0 mol%, 0.01 mol% is preferable.

A copolymer (B-1) can be manufactured by a well-known method. If the desired fluorine-containing copolymer is commercially available, it may be used as the copolymer (B-1).
A copolymer (B-1) may be used individually by 1 type, or may use 2 or more types together.

(PVDF (B-2))
PVDF (B-2) is a homopolymer of vinylidene fluoride (hereinafter also referred to as “VDF”), or 80 mol% or more and less than 100 mol% of VDF-derived units, and other monomers other than VDF It is a copolymer composed of more than 0 mol% and not more than 20 mol% of the derived unit. When the proportion of units derived from other monomers exceeds 20 mol%, the weather resistance of the cured film becomes insufficient.

  Examples of other monomers include tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, perfluorobutenoic acid, maleic acid, and vinyl acetate. From the viewpoint of weather resistance, tetrafluoroethylene, chloroethylene, Trifluoroethylene and hexafluoropropylene are preferred.

The mass average molecular weight (Mw) of PVDF (B-2) is preferably 100,000 to 500,000, particularly preferably 150,000 to 400,000. When the mass average molecular weight of PVDF (B-2) is within the above range, the cured film is difficult to break and the adhesion of the cured film to the substrate is excellent. As a result, the cured film is further excellent in bending workability.
The molecular weight distribution (Mw / number average molecular weight (Mn)) of PVDF (B-2) is preferably 1.0 to 5, particularly preferably 1.1 to 4.5.

PVDF (B-2) can be produced by polymerizing VDF and, if necessary, other monomers by a known polymerization method. Examples of the polymerization method include an emulsion polymerization method and a suspension polymerization method.
PVDF (B-2) may be used individually by 1 type, or may use 2 or more types together.

(Hydrolyzable silane compound (C))
Examples of the hydrolyzable silane compound (C) include tetrafunctional hydrolyzable silane compounds and multimers thereof. The tetrafunctional hydrolyzable silane compound is a compound in which four hydrolyzable groups are directly bonded to a silicon atom. A multimer of tetrafunctional hydrolyzable silane compounds is a multimer of tetrafunctional hydrolyzable silane compounds by condensation.

  Examples of the hydrolyzable group include an alkoxy group, an alkoxyalkyl group, an acyloxy group, an aryloxy group, an aminooxy group, an amide group, a ketoxime group, an isocyanate group, and a halogen atom. A group obtained by removing a hydrogen atom from a hydroxyl group of a monohydric alcohol such as an alkoxy group or an alkoxyalkyl group is preferred. Among these, an alkoxy group is particularly preferable, and the alkoxy group preferably has 4 or less carbon atoms, and particularly preferably 1 or 2.

The multimerization degree of the tetrafunctional hydrolyzable silane compound is preferably such that the composition does not produce a gel product. The degree of multimerization means the number of condensation molecules of the tetrafunctional hydrolyzable silane compound.
As the hydrolyzable silane compound (C), a tetraalkoxysilane multimer is preferable. As the straight-chain tetraalkoxysilane, a compound represented by the following formula (3) is preferable.
RO (Si (OR) ₂ O) _n R (3)
(In formula (3), n represents the multimerization degree of the multimer, and R represents an alkyl group having 1 to 4 carbon atoms. The n Rs in the multimer are the same or different from each other. May be.)
The normally available multimer is a mixture of multimers having different n, and the degree of multimerization is indicated by average n.
In formula (3), R includes a methyl group, an ethyl group, a propyl group, and a butyl group, and a methyl group and an ethyl group are preferable. As the hydrolyzable silane compound (C), a tetramethoxysilane multimer and a tetraethoxysilane multimer are more preferable, and a tetraethoxysilane multimer is most preferable.

The degree of multimerization of a tetrafunctional hydrolyzable silane compound such as tetraalkoxysilane or a multimer thereof may be represented by “silica content”. The “silica content” is a mass ratio of silica (SiO ₂ ) produced from the compound, and can be obtained by measuring the amount of silica produced by stably hydrolyzing and firing the compound. The “silica content” also indicates the ratio of silica generated with respect to one molecule of the compound, and is a value calculated by the following formula (4).
Silica content (parts by mass) = degree of multimerization × molecular weight of SiO ₂ / molecular weight of the compound (4)

  When the tetrafunctional hydrolyzable silane compound is a tetraalkoxysilane multimer, by setting the silica content to 40 parts by mass or more, the tetrafunctional hydrolyzable silane compound is a multimer of compounds other than tetraalkoxysilane. In this case, by setting the silica content to 35 parts by mass or more, the coating composition containing the multimer can prevent the occurrence of rain streak stains over a long period of time.

  Commercially available products may be used as the hydrolyzable silane compound (C), MKC silicate MS51, MS56 manufactured by Mitsubishi Chemical Corporation; methyl silicate 51 (tetramethoxysilane multimer) manufactured by Colcoat, ethyl silicate 40, 40T, 48 (both are tetraethoxysilane multimers); Matsumoto Kosho's ORGATIX SI series; Tama Chemicals ethyl silicate 40, 45 (both tetraethoxysilane multimers), and the like. Of these, tetraethoxysilane having a silica content of 45% by mass or more is preferable, and ethyl silicate 48 and ethyl silicate 45 are particularly preferable.

(Curing agent (D))
The curing agent (D) is a compound that cures the resin by reacting with the crosslinkable group of the resin having a crosslinkable group to crosslink the resin or increase the molecular weight.
The curing agent (D) has two or more reactive groups capable of reacting with the crosslinkable group of the copolymer (A), the copolymer (B), and other resin (G) described later.
Examples of the crosslinkable group possessed by the copolymer (A), the copolymer (B), and other resins (G) described later include a hydroxyl group, a carboxy group, an amino group, an epoxy group, an alkoxysilyl group, an isocyanate group, and the like. Can be mentioned.

The reactive group of the curing agent (D) is selected according to the crosslinkable group of the copolymer (A), the copolymer (B) and other resin (G) described later, the use of the coating composition, etc. Is done. For example, when the crosslinkable group is a hydroxyl group, the reactive group of the curing agent (D) is preferably an isocyanate group, a blocked isocyanate group, an amino group, an epoxy group, or the like.
When the coating composition is used in a powder coating, the reactive group of the curing agent (D) is not preferably one that easily reacts with the crosslinkable group of the resin at room temperature, and when the powder coating is heated and melted. It is preferably a reactive group capable of reacting. For example, a blocked isocyanate group is preferable to an isocyanate group having high reactivity at room temperature. The blocked isocyanate group is released from the blocking agent when the powder coating is heated and melted to form an isocyanate group, and the isocyanate group acts as a reactive group.

A known compound can be used as the curing agent (D). For example, isocyanate curing agent, blocked isocyanate curing agent, amine curing agent (melamine resin, guanamine resin, sulfoamide resin, urea resin, aniline resin, etc.), epoxy curing agent, β-hydroxyalkylamide curing Agents, triglycidyl isocyanurate-based curing agents, and the like.
Especially, since a copolymer (A) has a hydroxyl group, it is preferable that a hardening | curing agent (D) is a compound which has two or more reactive groups which can react with a hydroxyl group. From the point of being easy to form a cured film having high hardness, durability such as heat resistance and water resistance, weather resistance, scratch resistance and impact resistance, the coating composition is used as an isocyanate as a curing agent (D). It is particularly preferable to include at least one selected from the group consisting of a series curing agent, a blocked isocyanate curing agent, and an amine curing agent.

Examples of the isocyanate curing agent include non-yellowing polyisocyanate and non-yellowing polyisocyanate modified.
Examples of non-yellowing polyisocyanates include alicyclic polyisocyanates such as isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI); and aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI). Naruto.

Examples of non-yellowing polyisocyanate-modified products include the following modified products (c1) to (c4).
(C1) An isocyanurate of an aliphatic diisocyanate or an alicyclic diisocyanate.
(C2) A modified product having a structure represented by —Z—C (═O) —NH—, wherein an aliphatic diisocyanate or an alicyclic diisocyanate is modified with a polyol or a polyamine.
(C3) A structure represented by —Z—C (═O) —NH—, wherein a part of the isocyanate group of an aliphatic diisocyanate or an isocyanurate of an alicyclic diisocyanate is modified with a polyol or a polyamine. Modified body having
(C4) A modified product comprising a mixture of the modified product (c1) and the modified product (c2).
However, Z in -Z-C (= O) -NH- is an organic group derived from a polyol or polyamine. The number of functional groups possessed by the polyol or polyamine is preferably 2 to 3.

Examples of the blocked isocyanate curing agent include those in which the isocyanate group of the isocyanate curing agent is blocked.
The isocyanate group can be blocked with epsilon caprolactam (E-CAP), methyl ethyl ketone oxime (MEK-OX), methyl isobutyl ketone oxime (MIBK-OX), pyralidine, triazine (TA) and the like.

Examples of the amine curing agent include melamine resin, guanamine resin, sulfoamide resin, urea resin, aniline resin, and the like. Among these, a melamine resin is preferable because it has a high curing rate.
Specific examples of melamine resins include alkyl etherified melamine resins obtained by alkyl etherifying melamine. Among them, a melamine resin substituted with a methoxy group and / or a butoxy group is preferable.

  Examples of the epoxy curing agent include triglycidyl isocyanurate (TGIC), “TM239” (trade name, manufactured by Nissan Chemical Co., Ltd.) in which a methylene group is introduced into the glycidyl moiety of TGIC, trimellitic acid glycidyl ester and glycidyl terephthalate. Examples thereof include “PT-910” (trade name, manufactured by Ciba), which is a mixture of esters, and a resin having an epoxy group.

  Since the copolymer (A) has a hydroxyl group, an acid anhydride such as succinic anhydride, maleic anhydride or phthalic anhydride is allowed to act on a part of the hydroxyl group to generate a carboxy group, which is used as a crosslinkable group. May be. When a carboxy group is used as a crosslinkable group, the above-described amine curing agent and epoxy curing agent are preferably used.

(Pigment (E))
The pigment (E) is not particularly limited, and various pigments used in paints and the like can be used.
The pigment (E) is preferably at least one selected from the group consisting of bright pigments, rust preventive pigments, colored pigments and extender pigments. In particular, it is preferable to include a coloring pigment in order to obtain various color paints including white.

  The bright pigment is a pigment for brightening the cured film. Examples of the bright pigment include aluminum powder, nickel powder, stainless steel powder, copper powder, bronze powder, gold powder, silver powder, mica powder, graphite powder, glass flake, and scale-like iron oxide powder.

  A rust preventive pigment is a pigment for preventing corrosion and alteration of a base material with respect to a base material that requires rust prevention. As the rust preventive pigment, a lead-free rust preventive pigment having a low environmental load is preferable. Examples of lead-free rust preventive pigments include cyanamide zinc, zinc oxide, zinc phosphate, calcium magnesium phosphate, zinc molybdate, barium borate, and calcium cyanamide zinc.

The colored pigment is a pigment for coloring the cured film. Examples of the color pigment include titanium oxide, carbon black, iron oxide, phthalocyanine blue, phthalocyanine green, quinacridone, isoindolinone, benzimidazolone, and dioxazine.
As the coloring pigment, it is preferable to use a pigment having excellent weather resistance.

  The extender pigment is a pigment for improving the hardness of the cured film and increasing the thickness of the cured film. Moreover, when a base material is cut | disconnected by including an extender, the cut surface of a cured film can be cleaned. Examples of extender pigments include talc, barium sulfate, mica, and calcium carbonate.

  A pigment (E) may be used individually by 1 type, or may use 2 or more types together.

(Curing catalyst (F))
The curing catalyst (F) is used for accelerating the curing reaction and imparting excellent chemical performance and physical performance to the cured film. In particular, when curing at a low temperature in a short time, it is preferable to contain a curing catalyst (F).
A known catalyst can be used as the curing catalyst (F), and may be appropriately selected according to the type of the curing agent (D).

For example, when the curing agent (D) is an isocyanate curing agent or a blocked isocyanate curing agent, the curing catalyst (F) is preferably a tin catalyst or a zirconium catalyst.
Examples of the tin catalyst include tin octylate, tributyltin dilaurate, and dibutyltin dilaurate.
As a zirconium catalyst, a zirconium chelate etc. are mentioned, for example. Examples of commercially available zirconium catalysts include “K-KAT XC-4205” (trade name, manufactured by Enomoto Kasei Co., Ltd.).

When the curing agent (D) is an amine curing agent, a blocked acid catalyst is preferable as the curing catalyst (F).
Examples of the blocked acid catalyst include amine salts of various acids such as carboxylic acid, sulfonic acid and phosphoric acid. Of these, higher alkyl-substituted sulfonic acid amine salts such as diethanolamine salt or triethylamine salt of p-toluenesulfonic acid and diethanolamine salt or triethylamine salt of dodecylbenzenesulfonic acid are preferable.
A curing catalyst (F) may be used individually by 1 type, or may use 2 or more types together.

(Other resin (G))
The other resin (G) is a resin not corresponding to the copolymer (A) and the copolymer (B).
The other resin (G) may or may not have a crosslinkable group. Examples of the crosslinkable group include a hydroxyl group, a carboxy group, an amino group, an epoxy group, an alkoxysilyl group, and an isocyanate group.
As other resin (G), for example, fluorine-containing resin other than copolymer (A) and copolymer (B); acrylic resin, polyester resin, acrylic polyol resin, polyester polyol resin, urethane resin, acrylic silicone resin And non-fluorinated resins such as silicone resins, alkyd resins, epoxy resins, oxetane resins, amino resins, and the like.
Other resin (G) may be used individually by 1 type, or may use 2 or more types together.

When the coating composition is a solvent-based coating composition, the other resin (G) is compatible with the copolymer (A) and the copolymer (B) because the cured film tends to be glossy. And what can obtain a uniform cured film is preferable. In this case, the other resin (G) may be a thermosetting resin or a thermoplastic resin.
When including a thermosetting resin as other resin (G), it is preferable that other resin (G) can be connected with a copolymer (A) and a copolymer (B) with a hardening | curing agent (D). . Specifically, a polyester resin or an acrylic resin having a hydroxyl group, an epoxy group, a carbonyl group or the like at a terminal or a side chain is preferable.
When a thermoplastic resin is included as the other resin (G), the other resin (G) preferably includes a polar group that interacts with the hydroxyl group of the copolymer (A), such as an ester group. Specifically, polyester resins and acrylic resins having no crosslinkable group are preferable.

When the coating composition is a powder coating composition, the other resin (G) is preferably a thermosetting resin. Among these, those capable of separating layers without being compatible with the copolymer (A) in the melting and curing processes of the powder coating are preferable. When such a thermoplastic resin is contained as the other resin (G), a cured coating made of a melt of the powder coating is prepared by coating the base material with a powder coating containing the powder made of the coating composition in one coat. A fluorine-containing resin layer mainly composed of a cured product of the copolymer (A) contained in the powder when the cured component is reacted to react with the cured film and the cured film is cooled and cured. The other resin (G) contained in the powder or another resin layer mainly composed of a cured product thereof is layer-separated.
As the thermosetting resin, an acrylic resin, a polyester resin, an epoxy resin, a urethane resin, or a silicone resin having thermosetting properties are preferable, and the copolymer (A) is another resin layer because of excellent adhesion to the substrate. Polyester resin and acrylic resin are more preferable, and polyester resin is particularly preferable.

(Medium (H))
Examples of the medium (H) include water and organic solvents.
As an organic solvent, what melt | dissolves or disperse | distributes a copolymer (A) and another component as needed is preferable, and what melt | dissolves a copolymer (A) is especially preferable.
“Solubility of copolymer (A)” means that the amount of copolymer (A) that becomes a transparent solution when the copolymer (A) is added to an organic solvent at room temperature and mixed is organic It means 10% by mass or more based on the solvent (100% by mass).

Examples of the organic solvent include alcohols, ketones, esters, and hydrocarbons.
As alcohol, C1-C10 alcohol is preferable, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol etc. are mentioned.
The ketones are preferably alkyl ketones having 3 to 10 carbon atoms, and examples include acetone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, diisobutyl ketone, cyclohexanone, and isophorone.
Esters are preferably esters having 2 to 10 carbon atoms, such as methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, tertiary butyl acetate, methyl propionate, ethyl propionate, ethyl ethoxypropionate and the like. Can be mentioned.
Examples of the hydrocarbons include aromatic hydrocarbons such as xylene and toluene, and aliphatic hydrocarbon mixtures represented by mineral spirits.
These may be used alone or in combination of two or more.

When the coating composition of the present invention is a solvent-based coating composition, the coating composition preferably contains an organic solvent as the medium (H). In this case, the organic solvent is preferably one that dissolves the copolymer (A).
As an organic solvent, the compound containing a carbonyl group is preferable from the point which is excellent in the solubility of a copolymer (A). Specific examples include the aforementioned ketones and esters.

When the coating composition of the present invention is a water-based coating composition, the coating composition preferably contains an aqueous medium as the medium (H).
An aqueous medium means the medium which consists only of water or water and a small amount of organic solvent.
The content of the organic solvent in the aqueous medium is preferably 0 to 10% by mass with respect to the total mass of the aqueous medium. The upper limit of the content of the organic solvent is preferably 3% by mass or less, more preferably 1% by mass or less, further preferably 0.5% by mass or less, and particularly preferably 0.3% by mass or less.
When the aqueous medium contains an organic solvent, the organic solvent is preferably a water-soluble organic solvent that forms a uniform solution when mixed with water at an arbitrary ratio at room temperature. For example, acetone, methyl ethyl ketone, ethanol, methanol and the like can be mentioned.

(Other ingredients (I))
Other components (I) are copolymer (A), copolymer (B), hydrolyzable silane compound (C), curing agent (D), pigment (E), curing catalyst (F), other It is a component which does not correspond to any of resin (G) and a medium (H).
As other component (I), various well-known components can be used as a component mix | blended with a coating material, For example, what is shown below is mentioned.
Light stabilizers such as hindered amine light stabilizers.
Organic ultraviolet absorbers such as benzophenone compounds, benzotriazole compounds, triazine compounds, and cyanoacrylate compounds.
Inorganic UV absorbers such as zinc oxide and cerium oxide.
Matting agent such as ultra fine powder synthetic silica.
Nonionic, cationic or anionic surfactants.
Leveling agent.

(Content of each component in the coating composition)
The content of the copolymer (A) in the coating composition is the sum of the resin components (copolymer (A), copolymer (B), and other resin (G)) in the coating composition. 10-75 mass% is preferable with respect to 100 mass parts, and 20-70 mass% is more preferable. If content of a copolymer (A) is more than the lower limit of the said range, it will be excellent in the weather resistance of a cured film. If content of a copolymer (A) is below the upper limit of the said range, the cost of a cured film can be suppressed.

  The content of the copolymer (B) in the coating composition is preferably 10 to 90 parts by mass and more preferably 20 to 80 parts by mass with respect to 100 parts by mass of the total resin components in the coating composition. 30 to 70 parts by mass are particularly preferable. If content of a copolymer (B) is more than the lower limit of the said range, it will be excellent in the weather resistance of a coating film. If content of a copolymer (B) is below the upper limit of the said range, it will be excellent in the softness | flexibility of a coating film.

  The content of the hydrolyzable silane compound (C) in the coating composition is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of the copolymer (A), and is preferably 0.03 to 25 parts. Mass parts are more preferable, and 0.05 to 20 parts by mass are particularly preferable. If the content of the hydrolyzable silane compound (C) is not less than the lower limit of the above range, the effect of preventing rain streak contamination will increase. A cured film can be obtained.

The proportion of the hydrolyzable silane compound (C) in the coating composition is more preferably blended in an amount equal to or greater than the incompatible point with respect to the copolymer (A). This incompatibility point is the case where a solution obtained by dissolving the copolymer (A) and the hydrolyzable silane compound (C) in the medium (H) is applied to the surface of the glass plate and dried at 20 ° C. It is “the minimum mass of the hydrolyzable silane compound (C) that does not become cloudy with respect to the mass of the copolymer (A)” that can be confirmed by the presence or absence of the cloudiness of the coating film.
When the hydrolyzable silane compound (C) is blended at or above the incompatible point, generation of rain streaks can be more effectively prevented. Although this mechanism is not clear, after coating, the copolymer (A) and the hydrolyzable silane compound (C) undergo phase separation, and the hydrolyzable silane compound is near the surface of the cured film formed on the surface of the outdoor article. It is presumed that (C) is hydrolyzed and the surface becomes hydrophilic so that the occurrence of rain streaks can be more effectively prevented. This incompatible point has a different value depending on the type of component (a), the type of hydrolyzable silane compound (C), and the degree of multimerization.

  When the coating composition contains a curing agent (D), the content of the curing agent (D) in the coating composition is the total moles of crosslinkable groups of the copolymer (A) and the copolymer (B). It is preferable that the ratio of the number of moles of the reactive group in the curing agent (D) to the number (reactive group / crosslinkable group) is 0.1 to 1.2. The molar ratio is more preferably 0.2 to 1.1, and particularly preferably 0.3 to 1.1. When the content of the curing agent (D) is not less than the lower limit of the above range, the degree of cure of the coating is increased, and the adhesion between the cured film and the substrate, the hardness of the cured film, chemical resistance, and the like are excellent. When the content of the curing agent (D) is less than or equal to the upper limit of the above range, the cured film is not easily brittle, and the cured film has excellent weather resistance, heat resistance, chemical resistance, moisture resistance, and the like.

  When the coating composition contains the pigment (E), the content of the pigment (E) in the coating composition is preferably 20 to 200 parts by mass with respect to 100 parts by mass of the copolymer (A). 40-200 mass parts is more preferable. When the content of the pigment (E) is not less than the lower limit of the above range, the function of the pigment (E) can be efficiently expressed. When the content of the pigment (E) is not more than the upper limit of the above range, a cured film having excellent color resistance and color separation properties and excellent weather resistance can be easily obtained.

When the coating composition contains a curing catalyst (F), the content of the curing catalyst (F) in the coating composition is 0.00001 with respect to the solid content (100% by mass) in the coating composition. -10 mass% is preferable. When the content of the curing catalyst (F) is not less than the lower limit value of the above range, the catalytic effect can be sufficiently obtained. It is easy to form the cured film excellent in heat resistance and moisture resistance as content of a curing catalyst (F) is below the upper limit of the said range.
The “solid content” in the present specification means the total amount of the coating composition when the coating composition does not contain the medium (H), and when the coating composition contains the medium (H). The amount obtained by removing the medium (H) from the total amount of the coating composition is shown. The same applies to the solid content in the solvent-based paint described later and the solid content in the water-based paint.

  When the coating composition contains another resin (G), the content of the other resin (G) in the coating composition is based on 100 parts by mass of the total resin components in the coating composition. 10-90 mass parts is preferable, 20-80 mass parts is more preferable, and 25-75 mass parts is especially preferable. If content of other resin (G) is more than the said lower limit, manufacturing cost can be suppressed. If content of other resin (G) is below the said upper limit, the weather resistance of a cured film will be excellent.

The content of the medium (H) in the coating composition can be appropriately determined in consideration of the use of the coating composition, the solubility of the copolymer (A), and the like.
The total content of the other components (I) in the coating composition is preferably 45% by mass or less, particularly preferably 30% by mass or less, based on the solid content (100% by mass) of the coating composition.

(Use of paint composition)
The coating composition of the present invention can be used as various paints such as solvent-based paints, water-based paints, and powder paints, or as raw materials thereof.

[Solvent paint]
The solvent-based paint of the present invention contains a copolymer (A), a copolymer (B), a hydrolyzable silane compound (C), and an organic solvent as a medium (H), as necessary. , A curing agent (D), a pigment (E), a curing catalyst (F), another resin (G), another component (I), and the like.
Each of these components is the same as those described above.

The content of the organic solvent in the solvent-based coating is set to a desired solid content concentration in consideration of the solubility of the copolymer (A) and the copolymer (B), the viscosity of the solvent-based coating, the coating method, and the like. Can be determined appropriately.
The solid content concentration of the solvent-based paint is preferably 25 to 80% by mass, particularly preferably 35 to 75% by mass.
The preferable range of the content of each component other than the organic solvent in the solvent-based coating is the same as the preferable range of the content of each component in the coating composition.

  When the solvent-based paint of the present invention contains a curing agent (D), the solvent-based paint of the present invention contains a copolymer (A) and a copolymer (B), and does not contain a curing agent (D). Furthermore, it may be a two-component coating composition in which a curing liquid containing a curing agent (D) is added immediately before forming a coating film, and a one-component type that includes both a polymer (A) and a curing agent (D). It is good also as a coating composition.

(Method for producing solvent-based paint)
The solvent-based paint of the present invention includes, for example, a copolymer (A), a copolymer (B), a hydrolyzable silane compound (C), an organic solvent, and a curing agent (D) and a pigment (E ), Curing catalyst (F), other resin (G), other component (I) and the like are mixed by a known method used in the production of solvent-based paints. The mixing order of each component is not particularly limited.

[Water-based paint]
The water-based paint of the present invention includes a copolymer (A), a copolymer (B), a hydrolyzable silane compound (C), and an aqueous medium as a medium (H). The coating composition may contain a curing agent (D), a pigment (E), a curing catalyst (F), another resin (G), another component (I) and the like.
Each of these components is the same as those described above.

The content of the aqueous medium in the water-based coating is appropriately determined so as to obtain a desired solid content concentration in consideration of the dispersibility of the copolymer (A) and the copolymer (B), the viscosity of the water-based coating, the coating method, and the like. Can be determined.
The solid content concentration of the water-based paint is preferably 25 to 80% by mass, particularly preferably 35 to 75% by mass.
The preferred range of the content of each component other than the aqueous medium in the water-based paint is the same as the preferred range of the content of each component in the coating composition.

  When the water-based paint of the present invention contains a curing agent (D), the water-based paint of the present invention contains a copolymer (A) and a copolymer (B), and does not contain a curing agent (D). A two-component coating composition in which a curing liquid containing a curing agent (D) is added immediately before forming a coating film may be used, and a one-component coating composition that includes both a polymer (A) and a curing agent (D). It may be a composition for use.

(Method for producing water-based paint)
The water-based paint of the present invention includes, for example, a copolymer (A), a copolymer (B), a hydrolyzable silane compound (C) and an aqueous medium, and, if necessary, a curing agent (D) and a pigment (E). , Curing catalyst (F), other resin (G), other component (I) and the like are mixed by a known method used for the production of water-based paints. The mixing order of each component is not particularly limited.

[Powder paint]
The powder coating material of the present invention includes powder (hereinafter, also referred to as “powder (X)”) made of the coating composition of the present invention described above.
The powder coating material of the present invention may further contain other powders (hereinafter also referred to as “powder (Y)”) other than the powder (X) as necessary.

(Powder (X))
The powder (X) contains a copolymer (A), a copolymer (B), and a hydrolyzable silane compound (C), and if necessary, a curing agent (D) and a pigment (E). And a coating composition (hereinafter also referred to as “composition (α)”) which may contain a curing catalyst (F), another resin (G), another component (I), and the like.
Each of these components is the same as those described above.
The preferred range of the content of each component in the composition (α) is the same as the preferred range of the content of each component in the coating composition.

Powder (X) may be used individually by 1 type, or may use 2 or more types together.
The content of the powder (X) in the powder coating material of the present invention is preferably 20 to 100% by mass, more preferably 35 to 100% by mass, further preferably 50 to 100% by mass, and 75 to 100% by mass. Particularly preferred. The powder coating material may be a coating material made only of the powder (X). The higher the content of the powder (X), the better the weather resistance of the cured film.

(Powder (Y))
The powder (Y) includes, for example, a resin (G) other than the copolymer (A) and the copolymer (B), and does not include the copolymer (A) and the copolymer (B). Examples thereof include powders composed of a coating composition (hereinafter also referred to as composition (β)).
The composition (β) contains a curing agent (D), a pigment (E), a curing catalyst (F), another resin (G), another component (I) and the like as necessary. You may go out.
Each of these components is the same as those described above.
The preferred range of the content of each component in the composition (β) is the same as the preferred range of the content of each component in the coating composition.
Powder (Y) may be used individually by 1 type, or may use 2 or more types together.

(Production method of powder paint)
The powder coating material of this invention can be manufactured by the well-known manufacturing method which has the following process (a), process (b), process (c), and process (d), for example.
(A) A step of melt-kneading the composition (α) to obtain a kneaded product comprising the composition (α).
(B) A step of pulverizing the kneaded product to obtain a powder (X).
(C) A step of classifying the powder (X) as necessary.
(D) A step of dry blending the powder (X) and the powder (Y) as necessary.

  The average particle size of the powder (X) is preferably, for example, 25 to 50 μm with a 50% average volume particle size distribution. Measurement of the particle size of the powder is usually performed using a particle size measuring machine such as a type that captures a change in potential when passing through the pores, a laser diffraction method, an image determination format, a sedimentation velocity measurement method, and the like.

[Coated article]
The coated article of the present invention has a cured film formed on the surface of the base material using the aforementioned coating composition.

(Base material)
The shape, size, etc. of the substrate are not particularly limited.
The material of the base material is not particularly limited, and examples thereof include metals, stone materials, glass, resin, rubber, wood, and mixed materials thereof.

Examples of the metal include aluminum, iron, and magnesium. Aluminum is particularly preferable because it has excellent corrosion resistance, is lightweight, and has excellent performance for building materials.
Examples of the stone material include concrete and natural stone. Concrete is particularly preferable in that it has excellent strength.
It does not specifically limit as glass, A well-known glass can be used, For example, soda lime glass, alkali aluminosilicate glass, borosilicate glass, an alkali free glass, crystal glass, quartz glass etc. are mentioned. These glasses may be chemically strengthened.

The resin may be a fluorine-containing resin or a non-fluorine-containing resin. In view of the usefulness of forming a cured film using the paint of the present invention, a non-fluorinated resin is preferred.
Examples of non-fluorinated resins include vinyl resins, polyester resins, polyether resins, polyamide resins, thermoplastic polyimide resins, and thermoplastic elastomers.
An additive may be blended in the resin. As an additive, a well-known additive can be used, an inorganic filler or an organic filler may be used, and these may be used together. Examples of the resin in which the additive is blended include an FRP material.
Among the resins, the FRP material is preferable.
As rubber, nitrile rubber, acrylic rubber, silicone rubber, urethane rubber, chloroprene rubber, ethylene propylene rubber (EPD, EPDM), butadiene rubber, epichlorohydrin rubber, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, norbornene rubber, Examples thereof include fluororubber. From the viewpoint of solvent resistance and chemical resistance, fluorine rubber is preferred, and in particular, vinylidene fluoride rubber (FKM), tetrafluoroethylene-propylene rubber (FEPM), tetrafluoroethylene-perfluoromethyl vinyl ether rubber (FFKM). ) Is preferred.

  The surface of the substrate may be subjected to a surface treatment from the viewpoint of improving the adhesion of the cured film. Examples of the surface treatment include corona discharge treatment, plasma discharge treatment, treatment with a silane coupling agent, and the like.

(Water contact angle)
The water contact angle on the surface of the cured film of the coated article is preferably 1 to 55 °, more preferably 2 to 53 °, still more preferably 3 to 52 °, and particularly preferably 5 to 50 °. If it is more than the said lower limit, it will be excellent in the water resistance and anti-mold property of a coating film. On the other hand, if a water contact angle is below the said upper limit, it will be excellent in the stain resistance of a coating film.
The water contact angle in this specification refers to the contact angle when a water droplet (about 1 μL) is dropped on the surface of a cured film at a measurement temperature of 23 ° C. in air for a coated article. It is the value measured using the scientific company make, CA-X type).

(Method for manufacturing painted articles)
The coated article of the present invention can be produced by a known production method having the following step (e) and step (f).
(E) A step of forming a coating film by coating a coating material on the surface of the substrate.
(F) A step of curing the coating film to form a cured film.

[Function and effect]
According to the present invention, the cured film formed from the coating composition is excellent in low contamination due to the synergistic effect of the copolymer (A) having a high hydroxyl value and the hydrolyzable silane compound (C). This is because the hydroxyl group of the copolymer (A) interacts with the alkoxysilyl group of the hydrolyzable silane compound (C) so that the alkoxysilyl group is easily hydrolyzed earlier, so that the initial water contact angle Further, it is presumed that the coating film is easy to become familiar with water by adding the hydrophilicity of the copolymer (A). Furthermore, a part of hydroxyl groups in the copolymer (A) react with a part of alkoxysilyl groups in the hydrolyzable silane, whereby long-term low contamination can be achieved.
Moreover, since the alternating copolymerization ratio of the copolymer (A) and the copolymer (B) is high, it is excellent in weather resistance in a high-temperature and high-humidity region, and as a result, excellent low contamination is expressed over a long period of time. A cured film that can be maintained can be formed.

Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following description.
“%” Of the solid content indicates “% by mass”.

[Materials used]
(Main liquid)
Copolymer (A-1): Fluorine-containing copolymer of TFE / vinyl alcohol = 50/50 (mol%) obtained in Synthesis Example 1 described later (mass average molecular weight (Mw): 29,000, number Average molecular weight (Mn): 18,000, molecular weight distribution (Mw / Mn): 1.6, hydroxyl value: 390 mgKOH / g, alternating copolymerization ratio: 95% or more).
Copolymer (A ′): Fluorine-containing copolymer of TFE / vinyl alcohol = 50/50 (mol%) obtained in Synthesis Example 2 described later (mass average molecular weight (Mw): 275,000, number average Molecular weight (Mn): 74,000, molecular weight distribution (Mw / Mn): 3.3, hydroxyl value: 390 mgKOH / g, alternating copolymerization ratio: 80 to 85%.

Copolymer (B-1-1): Manufactured based on the description in JP-B-7-110890. TFE / hydroxyethyl allyl ether / vinyl versatate / vinyl benzoate / vinyl acetate = 43/13/32/6/6 (mol%) fluoropolymer (mass average molecular weight (Mw): 34,000, number average Molecular weight (Mn): 12,000, molecular weight distribution (Mw / Mn): 2.8, hydroxyl value: 55 mgKOH / g, alternating copolymerization ratio: 90%, solid content 50%).
Copolymer (B-1-2): Manufactured based on the description in JP-B-7-110890. Chlorotrifluoroethylene / ethyl vinyl ether / cyclohexyl vinyl ether / hydroxybutyl vinyl ether = 50/25/15/10 (mol%) fluoropolymer (mass average molecular weight (Mw): 38,000, number average molecular weight (Mn): 18,000, molecular weight distribution (Mw / Mn): 2.1, hydroxyl value: 53 mgKOH / g, alternating copolymerization ratio: 99%, solid content 50%).
Copolymer (B-2): PVDF resin, manufactured by Arkema, product name “Kynar (registered trademark) 500”.

Other resin (G): Acrylic polyol resin, manufactured by Hitachi Chemical Co., Ltd., product name “Hitaroid (registered trademark) 3546-3” solid content 50%.
Pigment (E): Titanium oxide, manufactured by DuPont, product name “Ti-Pure (registered trademark) R960”.
Curing catalyst (F): Dibutyltin dilaurate.

(Curing liquid)
Curing agent (D): HDI nurate type polyisocyanate resin, manufactured by Nippon Polyurethane Co., Ltd., product name “Coronate (registered trademark) HX”.
Hydrolyzable silane (C): methyl silicate, manufactured by Mitsubishi Chemical Corporation, product name “MKC silicate MS56”.
Metal complex: Aluminum trisacetylacetate, manufactured by Kawaken Fine Chemicals, product name “Aluminum Chelate A (W)”.

(Synthesis Example 1: Synthesis of copolymer (A-1))
<Polymerization process>
In an autoclave with a stainless steel stirrer having an internal volume of 1 L, 317 g of t-butyl alcohol, 111 g of t-butyl vinyl ether (hereinafter also referred to as “t-BuVE”), 0.98 g of potassium carbonate, and t-butyl peroxypivalate 2.72 g of 50% 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluorohexane solution (hereinafter also referred to as “PBPV”) is charged. Then, freeze deaeration was performed with liquid nitrogen to remove oxygen in the system. Next, 113 g of TFE was introduced into the autoclave and heated to 55 ° C. The pressure at this time point was 1.62 MPa. Thereafter, the reaction was continued for 8 hours. When the pressure dropped to 0.86 MPa, the autoclave was cooled with water, and the reaction was stopped by purging the unreacted gas. The obtained polymerization solution was poured into methanol, and the produced copolymer was precipitated, followed by vacuum drying to obtain a copolymer (P1) as a solid. The yield of copolymer (P1) was 122 g, and the yield was 56%.
Mw of the obtained copolymer (P1) was 29,000, Mn was 18,000, and Mw / Mn was 1.6. ^{From the 1} H NMR spectrum and the ¹⁹ F NMR spectrum, the copolymer composition ratio was TFE / t-BuVE = 50/50 (mol%). Moreover, it was found from the calculation from the copolymerization reactivity ratio of TFE and t-BuVE that the alternating copolymerization ratio of the copolymer (P1) was 95% or more, and it had a substantially alternating structure. .

<Deprotection process>
A 5 L flask was charged with 118 g of the copolymer (P1), 118 g of 36 mass% concentrated hydrochloric acid, and 1,540 g of ethanol, and the mixture was heated and stirred at an internal temperature of 78 ° C. for deprotection reaction. After the reaction was continued for 8 hours, the reaction solution was dropped into water to precipitate the copolymer, washed with water, and then vacuum dried at 90 ° C. to obtain 80 g of copolymer (A-1). .
¹ H NMR spectrum was measured, and in the copolymer (A-1), it was confirmed that 99% or more of the protective groups (t-butyl group derived from t-BuVE) had been eliminated and a hydroxyl group was formed.

(Synthesis Example 2: Synthesis of Copolymer (A ′))
<Polymerization process>
In an autoclave with a stainless steel stirrer having an internal volume of 1 L, 354 g of methyl acetate, 63 g of vinyl acetate (hereinafter referred to as “VAc”), and 50% of PBPV 1,1,1,2,2,3,3 2.3 g of 4,4,5,5,6,6-tridecafluorohexane solution was charged, and freeze deaeration was performed with liquid nitrogen to remove oxygen in the system. Next, 179 g of TFE was introduced into the autoclave and heated to 55 ° C. Thereafter, the reaction was continued for 10 minutes, and then the autoclave was cooled with water and purged with unreacted gas to stop the reaction. The obtained polymerization solution was poured into methanol, and the produced copolymer was precipitated, followed by vacuum drying to obtain a copolymer (P2) as a solid. The yield of copolymer (P2) was 110 g, and the yield was 45%.
Mw of the obtained copolymer (P2) was 278,000, Mn was 84,000, and Mw / Mn was 3.3. ^{From the 1} H NMR spectrum and the ¹⁹ F NMR spectrum, the copolymer composition ratio was TFE / VAc = 50/50 (mol%). Moreover, the alternating copolymerization ratio of the copolymer (P2) was 80 to 85% by calculation from the copolymerization reactivity ratio of both monomers.

<Deprotection process>
A 1 L flask was charged with 40 g of the copolymer (P2), 41 g of 36 mass% concentrated hydrochloric acid, and 520 g of ethanol, and the mixture was heated and stirred at an internal temperature of 78 ° C. for deprotection reaction. After the reaction was continued for 32 hours, the reaction solution was dropped into water to precipitate a copolymer, washed with water, and then vacuum dried at 90 ° C. to obtain 27 g of copolymer (A ′).
¹ H NMR spectrum was measured, and in the copolymer (A ′), it was confirmed that 99% or more of acetyl groups were eliminated and a hydroxyl group was generated.

〔Evaluation method〕
(Mass average molecular weight (Mw), number average molecular weight (Mn) of copolymer, molecular weight distribution (Mw / Mn))
The mass average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the copolymer obtained in each example were measured using a high-speed GPC device “HLC-8220GPC” manufactured by Tosoh Corporation. It measured by gel filtration chromatography (GPC) of gel conversion. Tetrahydrofuran was used as the eluent.

(Initial water contact angle test)
Using the contact angle meter (Kyowa Interface Science Co., Ltd., CA-X type), the contact angle when the water droplet was dropped on the surface of the cured film in the air with respect to the obtained test plate with the cured film. It was measured. A smaller water contact angle indicates higher hydrophilicity. The amount of water droplets was about 1 μL, and the measurement temperature was 23 ° C.

(High temperature and humidity test)
<Gloss retention>
A test plate with a cured film was installed outdoors in Naha City, Okinawa Prefecture. Gloss meter (Nippon Denshoku Industries Co., Ltd.) PG-1M). When the gloss value immediately before installation was taken as 100%, the ratio of the gloss value after 2 years was calculated as the gloss retention (unit:%), and the weather resistance was judged according to the following criteria. The gloss retention was measured and calculated according to JIS K 5600-1-7.
○ (excellent): The gloss retention was 80% or more, and no discoloration of the cured film was observed.
Δ (good): The gloss retention was 60 or more and less than 80, and no discoloration or the like of the cured film was observed.
X (defect): Gloss retention was less than 60%, and discoloration of the cured film was observed.

<Dirt of cured film>
The cured film after 2 years used for the evaluation of the gloss maintenance rate was visually checked for the degree of adhesion of dirt on the surface, and evaluated according to the following criteria.
○ (Good): Conspicuous dirt was not confirmed on the surface of the cured film.
X (defect): Dirt adhered to the entire surface of the cured film.

[Example 1]
(Manufacture of main liquid)
As shown in each component and blending amount shown in Table 1, 20.0 g of the fluorinated copolymer (A-1), 80.0 g of the fluorinated copolymer (B-1-1), and 40. 0 g, 0.0063 g of dibutyltin dilaurate and 35.0 g of xylene were added, and 175 g of glass beads having a diameter of 1 mm were further added, followed by stirring for 2 hours in a paint shaker. After stirring, filtration was performed to remove the glass beads to obtain a main liquid.

(Preparation of curable liquid)
9.0g of coronate HX, 10.0g of MS56, 1.5g of aluminum chelate D, and 19.0g of butyl acetate were sufficiently stirred with a disper to prepare a curing solution.

(Preparation of test plate with cured film)
The prepared main liquid and the curable liquid are mixed, and the paint obtained by sufficiently stirring the dried film thickness on the surface of a degreased dull steel plate (SPCC-SD) having a size of 150 mm × 70 mm and a thickness of 0.8 mm, The coating was formed by spray coating to 40 μm. Next, a cured film was formed by curing in a thermostatic chamber at 25 ° C. for 1 week to obtain a test plate (coated article) with a cured film.

[Example 2 and Comparative Examples 1 and 2]
A main liquid and a curable liquid were prepared in the same manner as in Example 1 except that each component and blending amount shown in Table 1 were used. Subsequently, after mixing and stirring the main liquid and the hardening | curing liquid, it carried out similarly to Example 1, and obtained the test plate (coated article) with a cured film.

Example 3 and Comparative Example 3
A main liquid and a curable liquid were prepared in the same manner as in Example 1 except that each component and blending amount shown in Table 1 were used. Next, after mixing and stirring the main liquid and the hardening liquid, spray the surface of a degreased dull steel plate (SPCC-SD) having a size of 150 mm × 70 mm and a thickness of 0.8 mm so that the dry film thickness becomes 40 μm. The coated film was dried in a hot air drying oven at 250 ° C. for 10 minutes to obtain a test plate with a cured film (coated article).

  The test plates with cured films obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to an initial water contact angle test and a high temperature and humidity test. Table 1 shows the amount of each component and the evaluation results.

As shown in Table 1, the cured film-attached test plates obtained in Examples 1 to 3 had lower initial water contact angles of the cured films than Comparative Examples 1 to 3. This indicates that the cured film-coated test plates obtained in Examples 1 to 3 are excellent in low contamination immediately after production.
Moreover, the test board with a cured film obtained in Examples 1 to 3 was superior in weather resistance and contamination resistance to Comparative Examples 1 to 3 after being installed for 2 years in a high-temperature and high-humidity environment.

  The paint composition of the present invention includes traffic lights, utility poles, road marking poles, bridges, railings, building materials (gates, fences, house siding materials, curtain walls, roofs, etc.), automobile bodies and parts (bumpers, Wiper blades, etc.), home appliances (air conditioner outdoor units, water heater exteriors, etc.), wind power generation blades, solar cell backsheets, solar power collector mirrors, eggplant battery exterior surfaces, etc. Is useful for forming.

Claims (5)

It has a unit represented by the following formula (1) and a unit represented by the following formula (2), has a number average molecular weight of 10,000 to 100,000, and a hydroxyl value of 150 to 500 mgKOH / g. A fluorine-containing copolymer (A) having an alternating copolymerization ratio of 95% or more,
One or both of the following fluorine-containing copolymer (B-1) and polyvinylidene fluoride (B-2),
And
A coating composition comprising a hydrolyzable silane compound (C).

[In the formula (1), X and Y are each independently H, F, CF ₃ or Cl. ]
Fluorine-containing copolymer (B-1): Unit based on fluoroolefin (b1), unit based on monomer having crosslinkable group (b2), unit based on vinyl ether compound having no crosslinkable group, and crosslink One or both of units based on a vinyl ester compound having no functional group (b3), a number average molecular weight of 5,000 to 100,000, a hydroxyl value of 1 to 120 mgKOH / g, The polymerization ratio is 90% or more.   The coating composition according to claim 1, further comprising at least one curing agent (D) selected from the group consisting of an isocyanate curing agent, a blocked isocyanate curing agent, and an amine curing agent.   The coated article which has the cured film formed using the coating composition of Claim 1 or 2 on the surface of a base material.   The coated article of Claim 3 whose water contact angle of the surface of the said cured film is 1-55 degrees.   The coated article according to claim 3 or 4, wherein the substrate is formed of at least one selected from the group consisting of metal, stone, glass, resin, rubber, wood, and a composite material thereof.