JP2015059211A - Aerosol composition and coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aerosol composition which is excellent in weather resistance, enables easy formation of a coating film which improves the durability of a to-be-coated object sufficiently and is useful in e.g. simple emergency measures for installations of e.g. factories and electric power plants and a coating method using the aerosol composition.SOLUTION: An aerosol composition includes a coating ingredient (I) comprising a fluorine-containing polymer (A) and a solvent (B) and a propellant (II), and the coating ingredient contains a hardener (C), as needed. A coating method comprises spraying the aerosol composition to coat.

Description

  The present invention relates to an aerosol composition and a coating method.

  The exterior surfaces of automobiles, ships, railway vehicles, airplanes and other transportation equipment, factories, power plants, etc. and buildings are painted with a coating composition for the purpose of enhancing their durability. There are many cases. In addition, after a long period of time has passed since painting, the coating film deteriorates, so that repainting repair is performed.

  However, in particular, when repainting and repairing is performed in facilities such as factories and power plants, buildings, etc., it is a very large-scale repair, which requires a lot of labor and time from budget application to construction. Therefore, it is advantageous in terms of cost and workability if simple repairs can be made each time the coating film is damaged by daily inspection or the like.

  By the way, as a method for simply coating an object to be coated, there is known a coating method in which an aerosol composition is sprayed onto an object to be coated to form a coating film using an aerosol can. Since the coating method can form a coating film by simply spraying an aerosol composition onto an object to be coated, it is easier to paint than brush coating or the like. Moreover, since the aerosol can is easy to carry, the work at a high place or the like is easy as compared with the case of carrying the can.

As the aerosol composition, for example, the following are known.
(I) An aerosol composition containing a paint component containing a resin having two or more siloxy groups in one molecule, a polyisocyanate compound and an organic solvent, and a propellant (Patent Document 1).
(Ii) An aerosol composition containing a coating component containing a siloxane polymer, a hydrophilicity-imparting agent and a polyisocyanate compound, and a propellant (Patent Document 2).

JP-A-8-92502 JP 2004-83816 A

  However, in the coating using the aerosol compositions (i) and (ii), the weather resistance of the formed coating film is insufficient, and it is difficult to sufficiently enhance the durability of the object to be coated.

  The present invention provides an aerosol composition that can easily form a coating film that is excellent in weather resistance and sufficiently enhances the durability of an object to be coated, and a coating method using the aerosol composition.

In order to achieve the above object, the present invention adopts the following configuration.
[1] An aerosol composition comprising a coating component (I) containing a fluoropolymer (A) and a solvent (B), and a propellant (II).
[2] The aerosol composition according to [1], wherein the fluoropolymer (A) includes a fluoropolymer (A1) having a hydroxyl group.
[3] The aerosol composition of [1] or [2], wherein the coating component (I) further contains a curing agent (C).
[4] A coating method comprising spraying the aerosol composition according to any one of [1] to [3].

If the aerosol composition of this invention is used, the coating film which is excellent in a weather resistance and can fully improve the durability of a to-be-coated object can be easily formed on a to-be-coated object.
According to the coating method of the present invention, a coating film can be formed simply by injecting an aerosol composition onto an object to be coated, so that the coating is easy, the weather resistance is excellent, and the durability of the object to be coated can be sufficiently enhanced. A coating film can be formed.

In this specification, the term “repeating unit directly formed by polymerization of monomers” and the term “repeating unit obtained by chemical conversion of a part of the repeating units formed by polymerization of the monomer” are collectively used. This is called “structural unit”.
In the present specification, the monomer represents a compound having a polymerizable double bond.
In this specification, the description of (meth) acrylic acid represents at least one of acrylic acid and methacrylic acid.
In the present specification, the crosslinkable group means a group that forms a crosslinked structure by reacting with each other or with a curing agent. 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.
In the present specification, a compound represented by the formula (1) is referred to as a compound (1). The same applies to compounds represented by other formulas.
In the present specification, a group represented by the formula (2) is referred to as a group (2).

≪Aerosol composition≫
The aerosol composition of the present invention comprises a coating component (I) containing a fluoropolymer (A) and a solvent (B), and a propellant (II).

<Paint component (I)>
The coating component (I) contains the fluorine-containing polymer (A) and the solvent (B) as essential components, and other than the curing agent (C), the curing catalyst (D), and the fluorine-containing polymer (A) as necessary. Resin (E), pigment (F), and other components (G) are included.
The coating component (I) preferably contains a curing agent (C).

[Fluoropolymer (A)]
When the aerosol composition of the present invention contains the fluorinated polymer (A), it is possible to form a coating film that has excellent weather resistance and can impart good durability to the object to be coated.
As the fluorine-containing polymer (A), a fluorine-containing polymer (A1) having a hydroxyl group is preferable from the viewpoint of easily forming a coating film excellent in weather resistance, durability, scratch resistance, and impact resistance. In addition, as the fluorine-containing polymer (A), a fluorine-containing polymer (A2) having a crosslinkable group other than a hydroxyl group (however, a fluorine-containing polymer having a hydroxyl group is excluded) may be used. You may use the fluorine-containing polymer (A3) which does not have.

(Fluoropolymer (A1))
As the fluorine-containing polymer (A1), a fluorine-containing polymer (A11) having the following structural unit (α1) and the following structural unit (α2) is more preferable. By using the fluoropolymer (A11), it becomes easy to form a coating film excellent in durability, weather resistance, scratch resistance and impact resistance.
(Α1) A structural unit based on a fluoroolefin.
(Α2) A structural unit based on a monomer having a hydroxyl group.

Structural unit (α1):
A fluoroolefin is a compound in which one or more hydrogen atoms of an olefin hydrocarbon (general formula C _n H _2n ) are substituted with a fluorine atom.
2-8 are preferable and, as for carbon number of a fluoro olefin, 2-6 are more preferable.
The number of fluorine atoms in the fluoroolefin (hereinafter referred to as “fluorine addition number”) is preferably 2 or more, and more preferably 3-4. When the fluorine addition number is 2 or more, the weather resistance of the formed coating film is improved. In the fluoroolefin, one or more hydrogen atoms not substituted with fluorine atoms may be substituted with chlorine atoms.

Examples of the fluoroolefin include C2-C3 fluoroolefins such as tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, hexafluoropropylene, and pentafluoropropylene.
As the fluoroolefin, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinylidene fluoride, and vinyl fluoride are preferable from the viewpoint of productivity and copolymerization with other monomers. Tetrafluoroethylene, chloro Trifluoroethylene is more preferable, and chlorotrifluoroethylene is most preferable from the viewpoint of excellent solubility in a solvent.

The structural unit (α1) contained in the fluoropolymer (A11) may be one type or two or more types.
As the structural unit (α1), a structural unit directly formed by polymerizing a fluoroolefin is preferable.

Structural unit (α2):
Specific examples of the monomer having a hydroxyl group include the following compounds.
2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 4-hydroxybutyl vinyl ether, 4-hydroxy-2-methylbutyl vinyl ether, 5-hydroxypentyl vinyl ether, Hydroxyalkyl vinyl ethers such as 6-hydroxyhexyl vinyl ether;
Ethylene glycol monovinyl ethers such as diethylene glycol monovinyl ether, triethylene glycol monovinyl ether, tetraethylene glycol monovinyl ether;
Hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, 4-hydroxybutyl allyl ether, glycerol monoallyl ether;
Hydroxyalkyl vinyl esters such as 2-hydroxyethyl vinyl ester and 4-hydroxybutyl vinyl ester;
Hydroxyalkyl allyl esters such as hydroxyethyl allyl ester and hydroxybutyl allyl ester;
(Meth) acrylic acid hydroxyalkyl esters such as hydroxyethyl (meth) acrylate.

  As the monomer having a hydroxyl group, hydroxyalkyl vinyl ethers are preferable from the viewpoint of easy availability, 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether are more preferable, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether is more preferred.

The structural unit (α2) possessed by the fluoropolymer (A11) may be one type or two or more types.
As the structural unit (α2), a structural unit directly formed by polymerizing a monomer having a hydroxyl group is preferable.

Note that the structural unit (α2) is not limited to a structural unit directly formed by polymerizing a monomer having a hydroxyl group. For example, the structural unit (α2) may be a structural unit obtained by the following method.
A structural unit having a carboxy group is converted to a structural unit having a hydroxyl group by saponifying a polymer having a structural unit having a carboxy group, obtained by polymerizing a monomer having a carboxy group such as vinyl carboxylate. How to convert to

The fluoropolymer (A11) more preferably has a structural unit (α3) other than the structural unit (α1) and the structural unit (α2) in addition to the structural unit (α1) and the structural unit (α2).
The structural unit (α3) is a structural unit based on a fluoroolefin and a monomer other than a monomer having a hydroxyl group (hereinafter also referred to as a monomer (a3)).

As the monomer (a3), a monomer having no crosslinkable group is preferable.
Specific examples of the monomer (a3) include olefins such as ethylene and isobutylene; vinyl esters such as vinyl acetate, vinyl pivalate, vinyl benzoate, and vinyl versatate; ethyl vinyl ether, butyl vinyl ether, 2- Examples include vinyl ethers such as ethylhexyl vinyl ether and cyclohexyl vinyl ether; and allyl ethers such as ethyl allyl ether, butyl allyl ether, and cyclohexyl allyl ether.

The monomer (a3) may be a monomer having a crosslinkable group other than a hydroxyl group, such as the monomer (a4) described later.
The structural unit (α3) contained in the fluoropolymer (A11) may be one type or two or more types.

  As the fluorinated polymer (A11), a structural unit based on chlorotrifluoroethylene as the structural unit (α1) from the viewpoint of easily forming a coating film excellent in weather resistance, durability, scratch resistance and impact resistance. The structural unit (α2) is selected from the group consisting of a structural unit based on at least one of 2-hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether, and the structural unit (α3) is selected from the group consisting of ethyl vinyl ether, 2-ethylhexyl vinyl ether, and cyclohexyl vinyl ether. It is particularly preferable to have a structural unit based on at least one kind.

  The ratio of the structural unit (α1) to the total (100 mol%) of the structural unit (α1) and the structural unit (α2) in the fluoropolymer (A11) is preferably 5 to 95 mol%, and 10 to 90 mol%. More preferred. When the proportion of the structural unit (α1) is at least the lower limit value, it is easy to form a coating film excellent in weather resistance. If the proportion of the structural unit (α1) is less than or equal to the upper limit value, the compatibility with the curing agent (C) will be good, and it will be dense and excellent in heat resistance, moisture resistance, scratch resistance and impact resistance. It is easy to form a coated film.

  The ratio of the structural unit (α2) to the total (100 mol%) of the structural unit (α1) and the structural unit (α2) in the fluoropolymer (A11) is preferably from 5 to 95 mol%, and from 10 to 90 mol%. More preferred. When the proportion of the structural unit (α2) is at least the lower limit value, it is easy to form a coating film having a high crosslink density and a high density and excellent in heat resistance, moisture resistance, scratch resistance and impact resistance. When the proportion of the structural unit (α2) is at most the upper limit value, the stability of the fluoropolymer (A11) is improved, and an aerosol composition having a long pot life can be easily obtained.

  The ratio of the structural unit (α1) to the total structural unit (100 mol%) of the fluoropolymer (A11) is preferably 20 to 99 mol%, more preferably 30 to 98 mol%, and particularly preferably 40 to 95 mol%. preferable. When the proportion of the structural unit (α1) is at least the lower limit value, it is easy to form a coating film excellent in weather resistance. If the proportion of the structural unit (α1) is less than or equal to the upper limit value, the compatibility with the curing agent (C) will be good, and it will be dense and excellent in heat resistance, moisture resistance, scratch resistance and impact resistance. It is easy to form a coated film.

  1-80 mol% is preferable, as for the ratio of the structural unit ((alpha) 2) with respect to all the structural units (100 mol%) of a fluoropolymer (A11), 2-70 mol% is more preferable, and 5-60 mol% is especially. preferable. When the proportion of the structural unit (α2) is at least the lower limit value, it is easy to form a coating film having a high crosslink density and a high density and excellent in heat resistance, moisture resistance, scratch resistance and impact resistance. When the proportion of the structural unit (α2) is at most the upper limit value, the stability of the fluoropolymer (A11) is improved, and an aerosol composition having a long pot life can be easily obtained.

0-60 mol% is preferable and, as for the ratio of the structural unit ((alpha) 3) with respect to all the structural units (100 mol%) of a fluoropolymer (A11), 0-50 mol% is more preferable. If the proportion of the structural unit (α3) is not more than the upper limit value, it is easy to achieve both the weather resistance of the coating film and the adhesion between the coating film and the object to be coated.
The proportion of the structural unit (α3) being 0 mol% means that the fluoropolymer (A11) does not have the structural unit (α3).
When the fluoropolymer (A11) has a structural unit (α3), the lower limit of the proportion of the structural unit (α3) is preferably 0.5 mol%.

  The proportion of each structural unit in the fluoropolymer (A11) can be controlled by adjusting the proportion of each monomer used in the polymerization for obtaining the fluoropolymer (A11), reaction conditions, and the like.

  In the case where the coating component (I) is a crosslinked type containing a curing agent (C), the hydroxyl value of the fluoropolymer (A1) is preferably 20 to 100 mgKOH / g, more preferably 30 to 70 mgKOH / g. When the hydroxyl value of the fluorinated polymer (A1) is at least the lower limit value, it is easy to form a coating film having a high crosslink density and being dense and excellent in heat resistance, moisture resistance, scratch resistance and impact resistance. If the hydroxyl value of the fluoropolymer (A1) is at most the upper limit, the stability will be improved and an aerosol composition having a long pot life will be easily obtained.

  When the coating component (I) is a lacquer type that does not contain the curing agent (C), the hydroxyl value of the fluoropolymer (A1) is preferably 1 to 30 mgKOH / g, more preferably 5 to 20 mgKOH / g. When the hydroxyl value of the fluoropolymer (A1) is at least the lower limit, it is easy to form a coating film having excellent adhesion to the article to be coated. When the hydroxyl value of the fluoropolymer (A1) is not more than the upper limit value, it is easy to form a coating film having excellent stability.

(Fluoropolymer (A2))
Examples of the fluoropolymer (A2) include a fluoropolymer having the following structural unit (α4) instead of the structural unit (α2) in the fluoropolymer (A11).
Structural unit (α4): a structural unit based on a monomer having a crosslinkable group other than a hydroxyl group (hereinafter also referred to as monomer (a4)).

Structural unit (α4):
Examples of the monomer (a4) include the following monomers (a4-1) to (a4-5).
(A4-1) A monomer having a carboxy group.
(A4-2) A monomer having an alkoxysilyl group.
(A4-3) A monomer having an amino group.
(A4-4) A monomer having an epoxy group.
(A4-5) A monomer having an isocyanate group.

Examples of the monomer (a4-1) include the following compounds.
3-butenoic acid, 4-pentenoic acid, 2-hexenoic acid, 3-hexenoic acid, 5-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 6-heptenoic acid, 3-octenoic acid, 7-octenoic acid, Unsaturated carboxylic acids such as 2-nonenoic acid, 3-nonenoic acid, 8-nonenoic acid, 9-decenoic acid or 10-undecenoic acid, acrylic acid, methacrylic acid, vinylacetic acid, crotonic acid, cinnamic acid;
Saturated carboxylic acid vinyl ethers such as vinyloxyvaleric acid, 3-vinyloxypropionic acid 3- (2-vinyloxybutoxycarbonyl) propionic acid, 3- (2-vinyloxyethoxycarbonyl) propionic acid;
Saturated carboxylic acid allyl ethers such as allyloxyvaleric acid, 3-allyloxypropionic acid, 3- (2-allyloxybutoxycarbonyl) propionic acid, 3- (2-allyloxyethoxycarbonyl) propionic acid;
Carboxylic acid vinyl ethers such as 3- (2-vinyloxyethoxycarbonyl) propionic acid and 3- (2-vinyloxybutoxycarbonyl) propionic acid;
Saturated polycarboxylic acid monovinyl esters such as monovinyl adipate, monovinyl succinate, vinyl phthalate, vinyl pyromellitic acid;
Unsaturated dicarboxylic acids such as itaconic acid, maleic acid, fumaric acid;
An acid anhydride in which two carboxy groups of the unsaturated dicarboxylic acids, such as maleic acid anhydride and itaconic acid anhydride, are dehydrated and condensed in the molecule;
Unsaturated carboxylic acid monoesters such as itaconic acid monoester, maleic acid monoester, and fumaric acid monoester.
As the monomer (a4-1), a monomer obtained by reacting the acid anhydride with the monomer having a hydroxyl group described above may be used.

Examples of the monomer (a4-2) include the following compounds.
_{CH 2 = CHCO 2 (CH 2} ) 3 Si (OCH 3) 3,
_{CH 2 = CHCO 2 (CH 2} ) 3 Si (OC 2 H 5) 3,
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 Si (OCH 3) 3,
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 Si (OC 2 H 5) 3,
_{CH 2 = CHCO 2 (CH 2} ) 3 SiCH 3 (OC 2 H 5) 2,
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 SiC 2 H 5 (OCH 3) 2,
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 Si (CH 3) 2 (OC 2 H 5),
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 Si (CH 3) 2 OH,
_{CH 2 = CH (CH 2)} 3 Si (OCOCH 3) 3,
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 SiC 2 H 5 (OCOCH 3) 2,
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 SiCH 3 (N (CH 3) COCH 3) 2,
_{CH 2 = CHCO 2 (CH 2} ) 3 SiCH 3 [ON (CH 3) C 2 H 5] 2,
_{CH 2 = C (CH 3)} CO 2 (CH 2) 3 SiC 6 H 5 [ON (CH 3) C 2 H 5] 2 acrylic acid esters or methacrylic acid esters such like.

CH ₂ = CHSi [ON = C (CH ₃ ) (C ₂ H ₅ )] ₃ ,
CH ₂ = CHSi (OCH ₃ ) ₃ ,
_{CH 2 = CHSi (OC 2 H} 5) 3,
CH ₂ = CHSiCH ₃ (OCH ₃ ) ₂ ,
CH ₂ = CHSi (OCOCH ₃ ) ₃ ,
CH ₂ = CHSi (CH ₃ ) ₂ (OC ₂ H ₅ ),
_{CH 2 = CHSi (CH 3)} 2 SiCH 3 (OCH 3) 2,
_{CH 2 = CHSiC 2 H 5 (} OCOCH 3) 2,
CH ₂ = CHSiCH ₃ [ON (CH ₃ ) C ₂ H ₅ ] ₂ ,
Vinyltrichlorosilane, or vinylsilanes such as partial hydrolysates thereof.

  Vinyl ethers such as trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, trimethoxysilylbutyl vinyl ether, methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, and triethoxysilylpropyl vinyl ether.

In addition, as the monomer (a4-2), a monomer obtained by reacting a compound having a functional group that reacts with a hydroxyl group and an alkoxysilyl group with the above-described monomer having a hydroxyl group is used. Also good. Examples thereof include a monomer (a4-2A) obtained by reacting a monomer having a hydroxyl group with the following compound (1). The monomer (a4-2A) has the following group (2).
OCN (CH ₂ ) _b SiX _a R ¹ _3-a (1)
—C (═O) NH (CH ₂ ) _b SiX _a R ¹ _3-a (2)
(Wherein R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, X is an alkoxy group having 1 to 5 carbon atoms, and a is an integer of 1 to 3) And b is an integer of 1 to 5.)

If the carbon number of the monovalent hydrocarbon group in R ¹ is 10 or less, the group (2) is suppressed from becoming too bulky, so that the condensation reaction of the alkoxy group (X) during curing of the coating film It can suppress becoming difficult to advance by steric hindrance. Therefore, the curability of the coating film becomes good, and excellent durability, weather resistance, scratch resistance and impact resistance are easily obtained.
R ¹ is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably a monovalent hydrocarbon group having 1 to 5 carbon atoms, and preferably a methyl group or an ethyl group.

If the carbon number of the alkoxy group of X is 5 or less, the alcohol component produced by the crosslinking reaction with the curing agent (C) is likely to volatilize. This makes it difficult for alcohol components to remain in the coating film, and it is easy to obtain a coating film having good heat resistance, water resistance, moisture resistance, weather resistance, scratch resistance, and impact resistance.
X is preferably an ethoxy group or a methoxy group.
b is preferably an integer of 2 to 4.

Specific examples of compound (1) include the following compounds.
3-isocyanatopropyltrimethoxysilane (X = methoxy group, a = 3, b = 3),
3-isocyanatopropyltriethoxysilane (X = ethoxy group, a = 3, b = 3),
3-isocyanatopropylmethyldimethoxysilane (X = methoxy group, R ¹ = methyl group, a = 2, b = 3),
3-isocyanatopropylmethyldiethoxysilane (X = ethoxy group, R ¹ = methyl group, a = 2, b = 3),
3-isocyanatopropyldimethylmethoxysilane (X = methoxy group, R ¹ = methyl group, a = 1, b = 3),
3-isocyanatopropyldimethylethoxysilane (X = ethoxy group, R ¹ = methyl group, a = 1, b = 3),
4-isocyanatobutyltrimethoxysilane (X = methoxy group, a = 3, b = 4),
4-isocyanatobutyltriethoxysilane (X = ethoxy group, a = 3, b = 4),
2-isocyanatoethyltrimethoxysilane (X = methoxy group, a = 3, b = 2),
2-isocyanatoethyltriethoxysilane (X = ethoxy group, a = 3, b = 2) and the like.

As the compound (1), 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane are preferable from the viewpoint of availability.
Moreover, as a monomer (a4-2), the monomer obtained by making the functional group which reacts with a carboxy group, and the compound which has an alkoxy silyl group react with a monomer (a4-1) is used. May be. For example, the monomer etc. which made the compound (1) react with the monomer (a4-1) the compound which replaced the isocyanate group with the epoxy group, the hydroxyl group, or the amino group are mentioned.

As a monomer (a4-3), the following compounds are mentioned, for example.
Amino vinyl ethers such as CH ₂ ═C—O— (CH ₂ ) _c —NH ₂ (where c is 0 or an integer of 1 to 10);
_{CH 2 = CH-O-CO} (CH 2) d -NH 2 (. However, d is an integer of 1 to 10) allylamines such as;
Aminomethylstyrene, vinylamine, acrylamide, vinylacetamide, vinylformamide, etc.

  As the monomer (a4-4), for example, glycidyl vinyl ether, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl methacrylate, 3,4-epoxycyclohexylmethyl vinyl ether, 4-vinyloxymethylcyclohexylglycidyl Examples include ether.

  Examples of the monomer (a4-5) include 2-isocyanate ethyl methacrylate, 2-isocyanate ethyl acrylate, 2-isocyanate ethyl ethoxy methacrylate, 2-isocyanate ethyl vinyl ether, and the like.

  The monomer (a4) is preferably the monomer (a4-2) from the viewpoint of easily forming a coating film excellent in durability, weather resistance, scratch resistance and impact resistance. -2A) is more preferred.

The structural unit (α4) contained in the fluoropolymer (A2) may be one type or two or more types.
As the structural unit (α4), a structural unit directly formed by polymerizing the monomer (a4) is preferable.

Note that the structural unit (α4) is not limited to a structural unit directly formed by polymerizing a monomer having a hydroxyl group. For example, the structural unit (α4) may be a structural unit obtained by the following method.
A method of introducing a carboxy group by reacting a polycarboxylic acid or its anhydride with a polymer obtained by polymerizing a monomer having a hydroxyl group,
A method of introducing an alkoxysilyl group by reacting an isocyanate alkylalkoxysilane with a polymer obtained by polymerizing a monomer having a hydroxyl group,
A method of introducing an isocyanate group by reacting a polyvalent isocyanate compound with a polymer obtained by polymerizing a monomer having a hydroxyl group.

(Fluoropolymer (A3))
Specific examples of the fluorine-containing polymer (A3) having no crosslinkable group include, for example, polytetrafluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene. A copolymer etc. are mentioned.

(Production method of fluoropolymer (A))
The production method of the fluoropolymer (A) is not particularly limited, and a method of polymerizing a fluoroolefin, a monomer having a hydroxyl group, a monomer (a3), a monomer (a4), or the like by a known method. Is preferred.

A known radical polymerization method can be adopted as the polymerization method. The polymerization form is not particularly limited, and solution polymerization, suspension polymerization, emulsion polymerization and the like can be employed.
Although the reaction temperature at the time of superposition | polymerization changes also with the radical polymerization initiator to be used, 0-130 degreeC is preferable. The reaction time is preferably 1 to 50 hours.

  Examples of the polymerization solvent include ion-exchanged water; alcohol solvents such as ethanol, butanol and propanol; saturated hydrocarbon solvents such as n-hexane and n-heptane; aromatic hydrocarbon solvents such as toluene and xylene; Examples thereof include ketone solvents such as methyl ethyl ketone and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate.

Examples of the radical polymerization initiator include the following compounds.
Peroxydicarbonates such as diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate;
peroxyesters such as t-hexylperoxypivalate and t-butylperoxypivalate;
Ketone peroxides such as cyclohexanone peroxide and methyl ethyl ketone peroxide;
Peroxyketals such as 1,1-bis (t-hexylperoxy) cyclohexane and 1,1-bis (t-butylperoxy) cyclohexane;
peroxycarbonate esters such as t-hexylperoxy-n-butyl carbonate and t-butylperoxy-n-propyl carbonate;
Diacyl peroxides such as isobutyryl peroxide and lauroyl peroxide;
Dialkyl peroxides such as dicumyl peroxide and di-t-butyl peroxide.

When employing emulsion polymerization, the polymerization can be carried out by using an initiator such as a water-soluble peroxide, a persulfate, or a water-soluble azo compound in water and in the presence of an anionic or nonionic emulsifier.
In addition, since a trace amount of hydrochloric acid or hydrofluoric acid may be generated during the polymerization reaction, it is preferable to add a buffer in advance during the polymerization.
In addition, the manufacturing method of a fluoropolymer (A) is not limited to the method mentioned above. For example, as described above, a method of introducing a carboxy group by reacting a polycarboxylic acid or the like after polymerization may be employed.

Commercially available products of the fluoropolymer (A) include, for example, the trade name “Lumiflon” (manufactured by Asahi Glass Co., Ltd.), the trade name “Fluonate” (manufactured by Dainippon Ink & Chemicals, Inc.), and the trade name “cefural coat” (Central Glass Co., Ltd.). Product name) “Zaflon” (manufactured by Toa Gosei Co., Ltd.), product name “Zeffle” (manufactured by Daikin Industries, Ltd.)
A fluoropolymer (A) may be used individually by 1 type, and may use 2 or more types together.

[Solvent (B)]
As a solvent (B), the solvent normally used for an aerosol composition can be used.
Specific examples of the solvent (B) include, for example, hydrocarbon solvents such as toluene, xylene and mineral spirits; ketone solvents such as methyl isobutyl ketone; ester solvents such as ethyl acetate, butyl acetate and amyl acetate; Ether solvents such as: glycol solvents such as ethylene glycol, diethylene glycol, propylene glycol, hexylene glycol; glycol ether solvents such as methyl ether, ethyl ether, propyl ether, and butyl ether of the glycol solvents.
A solvent (B) may be used individually by 1 type, and may use 2 or more types together.

[Curing agent (C)]
The curing agent (C) reacts with the hydroxyl group of the fluoropolymer (A1) or the crosslinkable group of the fluoropolymer (A2) to form a crosslinked structure, thereby forming a cured coating film by the aerosol composition. Fulfill.
It does not specifically limit as a hardening | curing agent (C), If the compound which has 2 or more of functional groups which react with this crosslinkable group according to the kind of crosslinkable group which a fluoropolymer (A) has is selected suitably. Good.

When the fluoropolymer (A1) having a hydroxyl group is used as the fluoropolymer (A), the curing agent (C) includes an isocyanate curing agent (C1), a blocked isocyanate curing agent (C2), and At least one selected from the group consisting of amino resins (C3) is preferred.
When the fluoropolymer (A) has a carboxy group, examples of the curing agent (C) include amine-based curing agents and epoxy-based curing agents.
When the fluoropolymer (A) has an amino group, examples of the curing agent (C) include a carboxy group-containing curing agent, an epoxy curing agent, and an acid anhydride curing agent.
When the fluoropolymer (A) has an epoxy group, examples of the curing agent (C) include a carboxy group-containing curing agent, an acid anhydride curing agent, and an amine curing agent.
When the fluoropolymer (A) has an alkoxysilyl group, the curing agent (C) is preferably a metal alkoxide.
When the fluoropolymer (A) has an isocyanate group, examples of the curing agent (C) include a hydroxyl group-containing curing agent and a carboxy group-containing curing agent.

(Isocyanate curing agent (C1))
As an isocyanate type hardening | curing agent (C1), a non-yellowing polyisocyanate and a non-yellowing polyisocyanate modified body are mentioned, for example. The isocyanate group of the isocyanate curing agent (C1) is not blocked.
Examples of the non-yellowing polyisocyanate include alicyclic polyisocyanates such as isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI); and aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI).

Examples of the non-yellowing polyisocyanate-modified product include the following modified products (c1) to (c4).
(C1) Isocyanurate of aliphatic diisocyanate or alicyclic diisocyanate.
(C2) A modified product having a structure represented by -C (= O) -NH-, wherein aliphatic diisocyanate or alicyclic diisocyanate is modified with a polyol or polyamine.
(C3) A modified product having a structure represented by -C (= O) -NH-, in which a part of the isocyanate group of an aliphatic diisocyanate or an alicyclic diisocyanate is modified with a polyol.
(C4) A modified product comprising a mixture of the modified product (c1) and the modified product (c2).

(Blocked isocyanate curing agent (C2))
The blocked isocyanate curing agent (C2) is obtained by blocking the isocyanate group of the isocyanate curing agent.
The isocyanate group can be blocked by epsilon caprolactam (E-CAP), methyl ethyl ketone oxime (MEK-OX), methyl isobutyl ketone oxime (MIBK-OX), pyrridine, triazine (TA), and the like.

(Amino resin (C3))
Examples of the amino resin (C3) include melamine resin, guanamine resin, sulfoamide resin, urea resin, aniline resin, and the like. Especially, a melamine resin is preferable from the point that a cure rate is quick.
Specific examples of the melamine resin include alkyl etherified melamine resins that are alkyl etherified. Especially, as a melamine resin, the melamine resin substituted by at least one of the methoxy group and the butoxy group is more preferable.

(Metal alkoxide)
Examples of the metal and metalloid of the metal alkoxide include Al, Ti, Si, etc. Si is preferable because a harder coating film can be formed and durability, weather resistance, scratch resistance and impact resistance are improved. .
As an alkoxy group of a metal alkoxide, a C1-C10 alkoxy group is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is especially preferable.

As the metal alkoxide, the following compound (3) is preferable.
(R ² ) _4-k Si (OR ³ ) _k (3)
However, the formula (3), ^{R 2} and ^{R 3} are each independently a monovalent hydrocarbon group having 1 to 10 carbon atoms, k is an integer of 2 to 4.

The monovalent hydrocarbon group for R ² may have a substituent. That is, part or all of the hydrogen atoms of the monovalent hydrocarbon group of R ² may be substituted with a substituent. As the substituent, a halogen atom is preferable, and a fluorine atom is more preferable.
R ² is preferably a methyl group, an ethyl group, a hexyl group, a decyl group, a phenyl group, or a trifluoropropyl group. When ^two or more R < ² > exists in a compound (3), it is preferable that several R < ² > is mutually the same from the point of the supply property of a raw material. A plurality of R ² may be different from each other.
The monovalent hydrocarbon group for R ³ is preferably an alkyl group having 1 to 10 carbon atoms, more preferably a methyl group or an ethyl group, and particularly preferably a methyl group. When two or more R < ³ > exists in a compound (3), it is preferable that several R < ³ > is mutually the same from the point that the reactivity of an alkoxy group becomes the same and it is easy to form a coating film uniformly. The plurality of R ³ may be different from each other.
As for k in a compound (3), 3-4 are preferable.

Specific examples of the compound (3) include the following compounds.
Tetrafunctional alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane;
Trifunctional alkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, trifluoropropyltrimethoxysilane;
Bifunctional alkoxysilanes such as dimethyldimethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, and diphenyldiethoxysilane.

As the compound (3), tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and phenyltrimethoxysilane are preferable from the viewpoint of curing speed and physical properties of the obtained coating film.
A compound (3) may be used individually by 1 type, and may use 2 or more types together.

Compound (3) may be used as a partially hydrolyzed condensate obtained by partial hydrolysis and condensation. The partial hydrolysis-condensation product is a compound obtained by condensing the compound (3) by partial hydrolysis so that two or more hydrolyzable groups (—OR ³ groups) remain in the molecule. It is. Although the overall structure of the partially hydrolyzed condensate is not clear, it is a polysilicate ester composed of a skeleton composed of —Si—O— bonds and an alkoxy group, and the skeleton may be linear or branched. It may be a chain or a cyclic structure.
The partially hydrolyzed condensate of compound (2) is more preferable as the degree of condensation is lower. The lower the degree of condensation of the partially hydrolyzed condensate, the better the compatibility with the fluoropolymer (A). In addition, the thermal expansion coefficient between the coating film to be formed and the object to be coated becomes closer, and peeling of the coating film from the object to be coated due to expansion and contraction due to heat becomes difficult to occur.

  The method for producing the partially hydrolyzed condensate of compound (3) is not particularly limited, and known methods for producing partially hydrolyzed condensates can be employed. For example, a method in which at least one of water, an acid, and a solvent is added to the compound (3) and partially hydrolyzed and condensed can be mentioned.

As the partially hydrolyzed condensate of compound (3), those having different degrees of condensation, structure, and types of alkoxy groups are commercially available, and examples thereof include the following.
Trade names “KR-500”, “KR-510”, “KR-213” (manufactured by Shin-Etsu Chemical Co., Ltd.), trade names “MKC silicate MS51”, “MKC silicate MS56” (manufactured by Mitsubishi Chemical Corporation) A condensate having an effective silica content of about 28 to 70% by mass, such as trade names “M silicate 51”, “ethyl silicate 40”, “ethyl silicate 45” (manufactured by Tama Chemical Co., Ltd.), or the like Trade names “HAS-1”, “HAS-6”, “HAS-10” (above, manufactured by Colcoat Co., Ltd.) and the like obtained by dissolving the product in ethanol or isopropanol.
The “effective silica content” is a value indicating the content of silica in terms of SiO ₂ when the polyalkyl silicate contained in the product is 100% by mass.
The partial hydrolysis-condensation product of compound (3) may be used individually by 1 type, and may use 2 or more types together.

Examples of the aluminum alkoxide include aluminum isopropoxide (Al [O—CH (CH ₃ ) ₂ ] ₃ ) and the like.
Examples of the titanium alkoxide include titanium butoxide (Ti (O—C ₄ H ₉ ) ₄ ).
Moreover, you may use the partial hydrolysis-condensation product which partially hydrolyzed and condensed the said aluminum alkoxide and titanium alkoxide so that two or more hydrolysable groups might remain in a molecule | numerator. These partial hydrolysis-condensation products are more preferable as the degree of condensation is lower from the viewpoint that compatibility with the fluoropolymer (A) is improved and peeling of the coating film from an object to be coated is difficult to occur.

  When the curing agent (C) is used in the aerosol composition of the present invention, for example, a coating component containing the fluoropolymer (A) and the solvent (B) as essential components and a coating component containing the curing agent (C) as essential components As a two-component type, they may be mixed just before injection. Moreover, when using blocked isocyanate type hardening | curing agent (C2), it is good also as a 1-component type coating component with which blocked isocyanate type hardening | curing agent (C2) is mix | blended previously.

  When the curing agent (C) is used in the aerosol composition of the present invention, the fluorine-containing polymer has a higher hardness and can easily form a coating film having superior durability, weather resistance, scratch resistance and impact resistance. The fluoropolymer (A1) is used as (A), and the curing agent (C) is selected from the group consisting of an isocyanate curing agent (C1), a blocked isocyanate curing agent (C2), and an amino resin (C3). A combination using at least one kind is particularly preferred.

[Curing catalyst (D)]
The aerosol composition of the present invention may contain a curing catalyst (D) for the purpose of accelerating the curing reaction and imparting good chemical performance and physical performance to the cured coating film. In particular, when curing at a low temperature in a short time, it is preferable to contain a curing catalyst (D).

Examples of the curing catalyst (D) include the following curing catalysts (D1) to (D3).
(D1) A curing catalyst that promotes a crosslinking reaction between the fluoropolymer (A1) and the isocyanate curing agent (C1) or the blocked isocyanate curing agent (C2).
(D2) A curing catalyst that promotes a crosslinking reaction between the fluoropolymer (A1) and the amino resin (C3).
(D3) A curing catalyst that promotes a crosslinking reaction between a fluoropolymer containing at least one of an alkoxysilyl group and a hydroxyl group and a metal alkoxide.

As the curing catalyst (D1), tin catalysts such as tin octylate, tributyltin dilaurate, and dibutyltin dilaurate are preferable.
As the curing catalyst (D2), a blocked acid catalyst is preferable. Examples of the blocked acid catalyst include various amine salts such as carboxylic acid, sulfonic acid, and phosphoric acid. Of these, higher alkyl-substituted sulfonic acid amine salts such as diethanolamine salt and triethylamine salt of p-toluenesulfonic acid and dodecylbenzenesulfonic acid are preferable.

  As the curing catalyst (D3), acidic phosphoric acid esters such as phosphoric acid monoester and phosphoric acid diester; acidic boric acid esters such as boric acid monoester and boric acid diester; addition reaction between acidic phosphoric acid ester and amine , Amine adducts such as addition reaction products of carboxylic acid compounds and amines; metal chelates such as tris (acetylacetonate) aluminum and tetrakis (acetylacetonate) zirconium; aluminum isopropoxide, titanium butoxide, etc. And metal alkoxides.

As the curing catalyst (D3), acidic phosphates are preferable from the viewpoint of curability and smoothness of the formed coating film. Moreover, C1-C8 monoalkyl phosphate, C1-C8 dialkyl phosphate, or mixtures thereof are more preferable from points, such as sclerosis | hardenability, the smoothness of the coating film formed, and water resistance.
A curing catalyst (D) may be used individually by 1 type, and may use 2 or more types together.

[Resin (E)]
Examples of the resin (E) include non-fluorine resins such as acrylic resins, polyester resins, acrylic polyol resins, polyester polyol resins, urethane resins, acrylic silicone resins, silicone resins, alkyd resins, epoxy resins, oxetane resins, and amino resins. Etc. The resin (E) may be a resin having a crosslinkable group and being cured by being crosslinked by the curing agent (C).

[Pigment (F)]
The aerosol composition of the present invention preferably contains a pigment (F) for the purpose of rust prevention, coloring, reinforcement and the like of the coating film to be formed.
The pigment (F) is preferably at least one pigment selected from the group consisting of rust preventive pigments, colored pigments and extender pigments.

The rust preventive pigment is a pigment for preventing corrosion or alteration of the object to be coated. Lead-free rust-proof pigments with low environmental impact are preferred. 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 color pigment is a pigment for coloring the coating film. Examples of the color pigment include titanium oxide, carbon black, and iron oxide.
The extender pigment is a pigment for improving the hardness of the coating film and increasing the thickness of the coating film. Examples of extender pigments include talc, barium sulfate, mica, and calcium carbonate.

[Other ingredients (G)]
Other components (G) include, for example, silane coupling agents for improving coating film adhesion; light stabilizers such as hindered amine light stabilizers; benzophenone compounds, benzotriazole compounds, triazine compounds, cyano Organic UV absorbers such as acrylate compounds; inorganic UV absorbers such as cerium oxide; matting agents such as ultrafine synthetic silica; nonionic, cationic or anionic surfactants; leveling agents Can be mentioned.

<Propellant (II)>
As the propellant (II), a propellant usually used in an aerosol composition can be used, and examples thereof include dimethyl ether, liquefied petroleum gas (LPG), various fluorocarbon derivatives, carbon dioxide gas, nitrogen gas and the like.
Propellant (II) may be used alone or in combination of two or more.

<Ratio of each component>
The proportion of the fluoropolymer (A1) in the fluoropolymer (A) (100 mass%) is preferably 50 mass% or more, more preferably 70 mass% or more, still more preferably 90 mass% or more, and 100 mass%. % Is particularly preferred.

  The proportion of the solvent (B) in the aerosol composition of the present invention may be appropriately determined in consideration of the solubility of the fluoropolymer (A), the appropriate viscosity when sprayed and applied, and the like.

  When the curing agent (C) is used in the aerosol composition of the present invention, the ratio of the fluoropolymer (A) to the total mass of the fluoropolymer (A) and the curing agent (C) is 10 to 90% by mass. Is preferable, 20-80 mass% is more preferable, and 30-70 mass% is further more preferable. If the ratio of the said fluoropolymer (A) is more than a lower limit, it will be easy to form the coating film excellent in the weather resistance. If the ratio of the fluoropolymer (A) is less than or equal to the upper limit value, it is easy to suppress the occurrence of cracks in the coating film, and adhesion to the object to be coated, durability, scratch resistance, and impact resistance It is easy to form a good coating film.

  When the curing catalyst (D) is blended in the aerosol composition of the present invention, the ratio of the curing catalyst (D) is determined by the coating component (I) at the time of use (the curing agent (C) when the curing agent (C) is used). 0.00001 to 10% by mass with respect to the total amount of solid content. If the ratio of the curing catalyst (D) is not less than the lower limit value, the catalytic effect can be sufficiently obtained. If the ratio of a curing catalyst (D) is below an upper limit, it will be easy to suppress that the remaining curing catalyst (D) has a bad influence on a coating film, and it will be easy to form a coating film with favorable heat resistance and water resistance.

  When the resin (E) is blended in the aerosol composition of the present invention, the proportion of the resin (E) is preferably 1 to 200 parts by mass with respect to 100 parts by mass of the fluoropolymer (A).

When the pigment (F) is blended in the aerosol composition of the present invention, the ratio of the pigment (F) is the coating component (I) at the time of use (including the curing agent (C) when the curing agent (C) is used). 50-500 mass% is preferable with respect to the total amount of solid content, and 100-400 mass% is more preferable. When the ratio of the pigment (F) is at least the lower limit value, the function of the pigment (F) is easily obtained. If the ratio of the pigment (F) is not more than the upper limit value, a coating film excellent in impact resistance and weather resistance can be easily formed.
The ratio of the other component (G) can be appropriately selected within a range not impairing the effects of the present invention.

  The volume ratio of the coating component (I) and the propellant (II) in the aerosol composition of the present invention is preferably 55:45 to 30:70, and more preferably 50:50 to 40:60. When the volume ratio of the coating component (I) and the propellant (II) is within the above range, it is easy to easily form a coating film that is excellent in weather resistance and sufficiently enhances the durability of the object to be coated.

<Effect>
Since the aerosol composition of the present invention contains the fluoropolymer (A), a coating film that is excellent in weather resistance and can sufficiently enhance the durability of the object to be coated can be formed on the object to be coated.

≪Painting method≫
The coating method of the present invention is characterized in that the aerosol composition of the present invention is sprayed for coating. The coating method of the present invention can employ known embodiments except that the aerosol composition of the present invention is used. Specifically, for example, a method of spraying and applying the aerosol composition of the present invention using a known one-pack type or two-pack type aerosol can.

  For example, when the curing agent (C) is used in the aerosol composition of the present invention, a two-pack type aerosol can is used, and the fluorine-containing polymer (A) and the solvent (B) are included as essential components and a curing agent ( The paint component containing C) as an essential component is filled in separate filling chambers in the aerosol can, mixed together immediately before use, and then sprayed and painted. When the curing agent (C) is not used in the aerosol composition of the present invention, coating is performed using a one-pack type aerosol can.

After the aerosol composition of the present invention is sprayed on the object to be coated, the aerosol composition may be spread with a sponge, a cloth, or the like, if necessary.
The object to be coated with the aerosol composition of the present invention is not particularly limited, and examples thereof include transportation equipment such as automobiles, ships, railway vehicles and airplanes, facilities such as factories and power plants, and buildings.

Since the coating method of the present invention can form a coating film simply by spraying an aerosol composition onto an object to be coated, it is easier to coat than a brush coating or the like. Moreover, since the aerosol can is easy to carry, the work at a high place or the like is easy as compared with the case of carrying the can. Moreover, in the coating method of this invention, the coating film which is excellent in weather resistance on the to-be-coated object, and can fully improve the durability of the to-be-coated object can be formed.
From the above, the coating method of the present invention can be suitably used for simple emergency treatment in large facilities such as factories and power plants.

Claims (4)

  An aerosol composition comprising a coating component (I) containing a fluoropolymer (A) and a solvent (B), and a propellant (II).   The aerosol composition according to claim 1, wherein the fluoropolymer (A) comprises a fluoropolymer (A1) having a hydroxyl group.   The aerosol composition according to claim 1 or 2, wherein the coating component (I) further contains a curing agent (C).   The coating method characterized by spraying and applying the aerosol composition as described in any one of Claims 1-3.