JP2018016773A - Water-based coating composition and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based coating composition capable of forming a coated film which prevents snow adhesion onto a surface of a base material, to provide a coated article having a coated film formed using the water-based coating composition thereon, and to provide a method for preventing snow adhesion onto a surface of a base material using the water-based coating composition.SOLUTION: A water-based coating composition is the water-based coating composition for forming a coated film which prevents snow adhesion onto a surface of a base material exposed to a freezing point, contains a polymerization unit based on fluoroolefin, also contains particles of a fluorine-containing polymer (A) having a carbon atom-hydrogen atom bond, particles of a fluorine-containing polymer (B) containing a polymerization unit based on (meth)acrylate having a polyfluoroalkyl group, and water. A difference between an average particle size of the particles of the fluorine-containing polymer (A) and an average particle size of the particles of the fluorine-containing polymer (B) is 100 nm or less in an absolute value.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous coating composition used for forming a coating film for preventing the adhesion of ice and snow on the surface of a substrate, and a coated article having a coating film formed using the same.

  Various coating compositions applied to the surface of a substrate have been proposed in order to suppress degradation of the substrate function and damage to the substrate due to water landing or icing snow. As such a coating composition, a solvent-type coating composition containing polytetrafluoroethylene particles, a crosslinkable fluoropolymer, a polyfluoroalkyl (meth) acrylate polymer, and an organic solvent has been proposed. (See Patent Document 1).

International Publication No. 2003/093388 Pamphlet

In Patent Document 1, the solvent is dispersed by a polyfluoroalkyl (meth) acrylate polymer contained in the solvent-type coating composition (an effect of dispersing polytetrafluoroethylene particles in a crosslinkable fluoropolymer). The uniformity of the components present on the surface of the coating film of the mold coating composition is enhanced, and the coating film exhibits water repellency and water drop slidability to prevent icing and snowing on the coating film.
However, the solvent-based coating composition of Patent Document 1 disperses and dissolves polytetrafluoroethylene particles, which are perfluoro-based polymers (fluorinated polymers having substantially no carbon bond-hydrogen bond). Of organic solvents. Solvent-type paint compositions are not preferred from the viewpoint of environmental measures such as global warming and photochemical smog (so-called VOC viewpoint), and there is a need for paint compositions that do not contain organic solvents. Is growing.
Furthermore, depending on the material of the substrate, the solvent-based coating composition may be denatured by the organic solvent during application, and the substrate to be applied and its mode may be limited.

  Then, this invention is made | formed in view of the said subject, Comprising: It aims at provision of the water-based coating composition which can form the coating film which prevents the snow and ice adhesion to the surface of a base material. Another object of the present invention is to provide a coated article having a coating film formed on the surface using the aqueous coating composition. Another object of the present invention is to provide a method for preventing the adhesion of snow and ice to the surface of a substrate using the water-based coating composition.

As a result of intensive studies, the inventors of the present invention have used a water-based coating composition containing the fluoropolymer (A) and the fluoropolymer (B) to form a coating film that prevents adhesion of ice and snow on the surface of the substrate. It has been found that a water-based coating composition that can be formed in the following manner is obtained.
That is, the present inventors have found that the above problem can be solved by the following configuration.

[1]
It is a water-based paint composition for forming a coating film that prevents ice and snow adhesion on the surface of a substrate exposed to below freezing point,
Particles of a fluoropolymer (A) containing a polymer unit based on a fluoroolefin and having a carbon atom-hydrogen atom bond;
Particles of a fluoropolymer (B) comprising polymerized units based on (meth) acrylate having a polyfluoroalkyl group;
Including water,
A water-based coating composition in which a difference between an average particle size of the particles of the fluoropolymer (A) and an average particle size of the particles of the fluoropolymer (B) is 100 nm or less in absolute value.
[2]
The water-based paint composition according to the above [1], wherein the difference between the fluorine content of the fluoropolymer (A) and the fluorine content of the fluoropolymer (B) is 30% by mass or less in absolute value. object.
[3]
Content of the said fluoropolymer (A) is 75-99 mass% with respect to the total mass of the said fluoropolymer (A) and the said fluoropolymer (B), The said fluoropolymer The water-based coating composition according to the above [1] or [2], wherein the content of (B) is 1 to 25% by mass.
[4]
The coated article which has a base material and the coating film arrange | positioned on the said base material and formed using the aqueous coating composition as described in any one of said [1]-[3].
[5]
On the surface of the substrate exposed to below freezing point,
Particles of a fluoropolymer (A) containing a polymer unit based on a fluoroolefin and having a carbon atom-hydrogen atom bond;
Particles of a fluoropolymer (B) comprising polymerized units based on (meth) acrylate having a polyfluoroalkyl group;
Including water,
Forms a coating film of an aqueous coating composition in which the difference between the average particle size of the fluoropolymer (A) particles and the average particle size of the fluoropolymer (B) particles is 100 nm or less in absolute value And the method of preventing the snow and ice adhesion to the surface of a base material.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based coating composition which forms the coating film which prevents ice and snow adhesion on the surface of a base material, and its coated article are provided.

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 “polymerization unit”.
Moreover, the numerical range represented using “to” means a range including numerical values described before and after “to” as the lower limit value and the upper limit value.
“(Meth) acrylate” is a generic term for acrylate and methacrylate, and “(meth) acrylic” is a generic term for “acrylic” and “methacrylic”.

The feature of the aqueous coating composition for forming a coating film for preventing adhesion of ice and snow on the surface of the substrate exposed to below freezing point of the present invention is a carbon atom-hydrogen atom containing a polymer unit based on fluoroolefin. A fluorine-containing polymer (A) particle having a bond; a fluorine-containing polymer (B) particle containing a polymer unit based on a (meth) acrylate having a polyfluoroalkyl group; and water. The difference between the average particle size of the particles of the coalescence (A) and the average particle size of the particles of the fluoropolymer (B) is that the absolute value is 100 nm or less.
The reason why the water-based coating composition of the present invention forms a coating film excellent in ice / snow adhesion preventing effect on the substrate surface is not necessarily clear, but can be considered as follows.

In the present invention, the fluoropolymer (A) and the fluoropolymer (B) are considered to form particles (emulsion) each having a carbon atom-hydrogen atom bond and excellent in water stability. Furthermore, when the average particle size of the particles of the fluoropolymer (A) and the average particle size of the particles of the fluoropolymer (B) satisfy the above-described configuration, the coating film becomes a fluoropolymer (A). It is considered that the particles have a base layer (lower layer part) packed tightly, and the fluoropolymer (B) particles have a surface layer (upper layer part) oriented closely. That is, the coating film formed from the water-based coating composition of the present invention is excellent in water repellency and water slidability because the fluoropolymer (B) is uniformly exposed on the surface of the coating film. It is thought that ice and snow adhesion preventive properties are imparted. In addition, since the base layer formed from the fluoropolymer (A) is located in the lower layer of the coating film, a coating film excellent in adhesion and followability can be obtained, and the fluoropolymer (B) It is presumed that the orientation of the particles is improved, and the effects of water repellency and water droplet slidability are more remarkably exhibited.
In addition, in the preferable aspect, these effects of this invention express more notably, and it explains in full detail below.

If the difference between the average particle size of the fluoropolymer (A) particles and the average particle size of the fluoropolymer (B) particles is 100 nm or less in absolute value, it is not particularly limited and is preferably 75 nm or less. 50 nm or less is more preferable.
The average particle diameter of the fluoropolymer (A) particles and the fluoropolymer (B) particles in this specification is determined by dynamic light scattering using ELS-8000 (manufactured by Otsuka Electronics Co., Ltd.). It is set as the value of D50 calculated | required. D50 is the particle diameter of 50 volume% of the cumulative volume calculated from the small particle side in the particle size distribution of the particles measured by the dynamic light scattering method.

The average particle diameter of the fluoropolymer (A) particles is preferably 200 nm or less. The lower limit is preferably 10 nm or more, and more preferably 50 nm or more. When it is within the above range, the base layer (lower layer part) in which the fluoropolymer (A) is densely packed is easily formed in the coating film formation, and the coating film has water resistance and adhesion to the substrate. In addition to excellent properties and followability, performances of water repellency and water droplet slidability due to improved surface orientation of the fluoropolymer (B) are more remarkably exhibited.
The average particle size of the fluoropolymer (B) particles is preferably 200 nm or less. The lower limit is preferably 10 nm or more, particularly preferably 50 nm or more. When it is within the above range, the packing between the fluoropolymer (A) particles and the fluoropolymer (B) particles becomes denser in the coating film formation, and the durability of the coating film is likely to be improved. .

In the present invention, the absolute value of the difference between the fluorine content of the fluoropolymer (A) and the fluorine content of the fluoropolymer (B) is preferably 30% by mass or less, more preferably 25% by mass or less. . When it is within the above range, in the aqueous coating composition, not only the particles of the fluorine-containing polymer (A) and the particles of the fluorine-containing polymer (B) are easily dispersed uniformly, but also in the coating film formation, The particles of the polymer (A) and the particles of the fluoropolymer (B) are packed more densely, and the durability of the coating film is further improved.
Specifically, the fluorine content of the fluorine-containing polymer (A) is 15 to 60% by mass, and the fluorine content of the fluorine-containing polymer (B) is from the viewpoint of water repellency and water droplet slippage of the coating film. The difference between the fluorine content of the fluoropolymer (A) and the fluorine content of the fluoropolymer (B) is 30% by mass or less in absolute value. preferable.

Hereinafter, the fluoropolymer (A) containing a polymer unit based on a fluoroolefin and having a carbon atom-hydrogen atom bond will be described in detail. The carbon atom-hydrogen atom bond in the fluoropolymer (A) may be contained in a polymer unit based on a fluoroolefin, or may be contained in a polymer unit other than a polymer unit based on a fluoroolefin.
_{Fluoroolefins, CF 2 = CF 2, CF} 2 = CFCF 3, CF 2 = CFCl, CF 2 = are preferred CHF or _{CF 2 = CH 2, CF 2} = CF 2, CF 2 = CFCl or _CF 2 = CH ₂ Is more preferable.
The content of the polymer units based on the fluoroolefin is preferably 20 to 70 mol%, more preferably 30 to 60 mol%, of all the polymerized units (100 mol%) of the fluoropolymer (A).

  The fluorinated polymer (A) may contain polymerized units other than the fluoroolefin. The polymerization unit is a polymerization unit based on a monomer having a monovalent saturated hydrocarbon group or a monovalent saturated hydrocarbon group containing an etheric oxygen atom in its side chain (hereinafter also referred to as monomer (a1)). Alternatively, a polymer unit based on a monomer having a crosslinkable group in the side chain (hereinafter also referred to as monomer (a2)) is preferable.

The monomer (a1) has a polymerizable group that forms the main chain of the polymer and has a monovalent saturated hydrocarbon group or a monovalent saturated hydrocarbon group containing an etheric oxygen atom in the side chain. There is no particular limitation as long as it is a monomer.
The polymerizable group is preferably a vinyl group, an allyl group, a vinyl ester group, an allyl ester group, an acryloyl group, a methacryloyl group or an allyl ester group, and more preferably a vinyl group, an allyl group, a vinyl ester group, or an allyl ester group.
The monovalent saturated hydrocarbon group preferably has 1 to 40 carbon atoms, and more preferably 4 to 24 carbon atoms. Moreover, the monovalent saturated hydrocarbon group may consist of a chain structure, may contain a cyclic structure, or may consist only of a cyclic structure. Furthermore, the cyclic structure may be a monocyclic structure or a polycyclic structure.
Specific examples of the monovalent saturated hydrocarbon group or the monovalent saturated hydrocarbon group containing an etheric oxygen atom include an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, and a polyoxyalkylene monoalkoxy group. The polyoxyalkylene monoalkoxy group is a polyoxyalkylene group (preferably a polyoxymethylene unit, a polyoxyethylene unit, or a polyoxypropylene unit), and the end not bonded to the polymerizable group is an alkoxy group. Means a group (for example, a group represented by — (C ₂ H ₄ O) _m —CH _3, where m represents the number of repeating units), which is a group (preferably a methyl group or an ethyl group).
Specific examples of the monomer (a1) include nonyl vinyl ether, 2-ethylhexyl vinyl ether, hexyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, tert-butyl vinyl ether, cyclohexyl vinyl ether, 4-cyclohexyl cyclohexyl vinyl ether, 1-decahydronaphthyl. Vinyl ethers such as vinyl ether, 2-decahydronaphthyl vinyl ether, 1-norbornyl vinyl ether, 1-adamantyl vinyl ether, spiro [3.4] octyl vinyl ether, (poly) oxyethylene monomethyl vinyl ether, (poly) oxypropylene monomethyl vinyl ether, Allyl ethers such as ethyl allyl ether and hexyl allyl ether, carboxylic acids (acetic acid, butyric acid, pivalin) , Benzoic acid, vinyl esters of propionic acid, etc.), carboxylic acids (acetic, butyric, pivalic acid, benzoic acid, allyl esters of propionic acid, etc.).
As the monomer (a1), one type may be used alone, or two or more types may be used.

  The polymerization unit based on the monomer (a1) is preferably 0 to 50 mol%, more preferably 5 to 45 mol%, of all the polymerization units (100 mol%) of the fluoropolymer (A), 15 More preferred is ˜40 mol%.

The monomer (a2) has a polymerizable group that forms the main chain of the polymer and contains a monovalent saturated hydrocarbon group containing a crosslinkable group, or a crosslinkable group and an etheric oxygen atom. Monomers having a monovalent saturated hydrocarbon group in the side chain are preferred.
The polymerizable group is preferably a vinyl group, an allyl group, a vinyl ester group, an allyl ester group, an acryloyl group, a methacryloyl group or an allyl ester group, and particularly preferably a vinyl group, an allyl group, a vinyl ester group, or an allyl ester group.
The monovalent saturated hydrocarbon group preferably has 1 to 40 carbon atoms, and more preferably 4 to 24 carbon atoms. Moreover, the monovalent saturated hydrocarbon group may consist of a chain structure, may contain a cyclic structure, or may consist only of a cyclic structure. Furthermore, the cyclic structure may be a monocyclic structure or a polycyclic structure.
The crosslinkable group is preferably a functional group having an active hydrogen (hydroxy group, carboxy group, amino group, sulfo group or the like) or a hydrolyzable silyl group (alkoxysilyl group or the like), more preferably a hydroxy group or a carboxy group.
Specific examples of the monovalent saturated hydrocarbon group containing a crosslinkable group and the monovalent saturated hydrocarbon group containing a crosslinkable group and an etheric oxygen atom include a carboxyalkyl group, a hydroxyalkyl group, a hydroxycycloalkyl group, A polyoxyalkylene monool group may be mentioned. The polyoxyalkylene monool group is a polyoxyalkylene group (preferably a polyoxymethylene unit, a polyoxyethylene unit, or a polyoxypropylene unit), and the terminal not bonded to the polymerizable group is a hydroxy group. groups form a group _(e.g., -. _(a group represented by _C 2 H 4 _O) n -H Here, n represents the number of repeating units.) means.
Specific examples of the monomer (a2) include 2-hydroxyethyl vinyl ether, 4-hydroxymethylcyclohexyl vinyl ether, 4-hydroxybutyl vinyl ether, cyclohexane dimethanol monovinyl ether, hydroxyethyl allyl ether, hydroxyethyl acrylate, hydroxy methacrylate _{ethyl, CH 2 = CH-O-} CH 2 -cycloC 6 H 10 -CH 2 -O- (CH 2 CH 2 O) n H (n represents the number of repeating units.) can be mentioned.

  The content of polymerized units based on the monomer (a2) is preferably 0 to 20 mol%, more preferably 0 to 15 mol%, of all the polymerized units (100 mol%) of the fluoropolymer (A). preferable. In particular, when the monomer (a2) is a monomer having a polymerizable group that forms the main chain of the polymer and a polyoxyalkylene monool group, the fluorine-containing polymer (A) in water There is an effect of improving dispersion stability. In this case, the content of the polymerized units based on the monomer (a2) is preferably 0.4 mol% or more of the total polymerized units (100 mol%) of the fluoropolymer (A), The mol% or more is more preferable, and 2.0 mol% or more is more preferable. The upper limit is not particularly limited, but is preferably 10 mol% or less.

  The number average molecular weight (Mn) of the fluoropolymer (A) is preferably from 30,000 to 200,000, more preferably from 50,000 to 180,000. The number average molecular weight (Mn) of the fluoropolymer (A) is a number average molecular weight (Mn) measured by gel permeation chromatography using polystyrene as a standard substance.

Hereinafter, the fluoropolymer (B) containing a polymer unit based on a (meth) acrylate having a polyfluoroalkyl group will be described in detail. The fluorinated polymer (B) is a polymer other than the fluorinated polymer (A) and does not contain a polymer unit based on a fluoroolefin.
The (meth) acrylate having a polyfluoroalkyl group has an acryloyl group (including a structure in which a hydrogen atom of the acryloyl group is substituted with a chlorine atom) or a methacryloyl group, and at least one of the carbon atom-hydrogen atom bond is a carbon atom- If it is a compound which has two or more alkyl groups (fluoroalkyl group) substituted by the fluorine atom bond, it will not specifically limit. The polyfluoroalkyl group preferably has 1 to 12 carbon atoms. The polyfluoroalkyl group may be linear or branched. The polyfluoroalkyl group may have a cyclic structure. The substituted group is preferably — (CF ₂ ) ₄ F, — (CF ₂ ) ₅ F, or — (CF ₂ ) ₆ F.

Specific examples of the (meth) acrylate having a polyfluoroalkyl group include the following compounds.
_{CH 2 = C (Cl) C} (O) OCH 2 CH 2 (CF 2) 4 F,
_{CH 2 = C (Cl) C} (O) OCH 2 CH 2 (CF 2) 6 F,
_{CH 2 = C (CH 3)} C (O) OCH 2 CH 2 (CF 2) 4 F,
_{CH 2 = C (CH 3)} C (O) OCH 2 CH 2 (CF 2) 6 F,
_{CH 2 = CHC (O) OCH} 2 CH 2 (CF 2) 4 F,
_{CH 2 = CHC (O) OCH} 2 CH 2 (CF 2) 6 F,
_{CH 2 = C (CH 3)} C (O) NHCH 2 CH 2 (CF 2) 4 F,
_{CH 2 = C (CH 3)} C (O) NHCH 2 CH 2 (CF 2) 6 F,
_{CH 2 = C (CH 3)} C (O) NHSO 2 (CF 2) 4 F,
_{CH 2 = C (CH 3)} C (O) NHSO 2 (CF 2) 6 F
_{CH 2 = CHC (O) OCH} 2 CH 2 N (R) SO 2 (CF 2) 4 F
_{CH 2 = CHC (O) OCH} 2 CH 2 N (R) SO 2 (CF 2) 6 F
_{CH 2 = C (CH 3)} C (O) OCH 2 CH 2 N (R) SO 2 (CF 2) 4 F
_{CH 2 = C (CH 3)} C (O) OCH 2 CH 2 N (R) SO 2 (CF 2) 6 F
However, R represents a C1-C4 alkyl group.

  The content of the polymerized units based on the (meth) acrylate having a polyfluoroalkyl group is preferably 20 to 70 mol% of the total polymerized units (100 mol%) of the fluoropolymer (B), preferably 30 to 60 mol%. Mole% is more preferable. When the content is not less than the lower limit, the coating film is excellent in water drop sliding properties, and when the content is not more than the upper limit value, the coating film is excellent in film forming properties and durability.

The fluoropolymer (B) may contain polymer units other than the polymer units based on the (meth) acrylate having a polyfluoroalkyl group (however, the fluoropolymer (B) is a fluoropolymer (B) It is a polymer different from A), and the fluorinated polymer (B) preferably does not contain a polymer unit based on a fluoroolefin. The polymer unit is preferably a polymer unit based on (meth) acrylate containing no fluorine atom.
The (meth) acrylate containing no fluorine atom is preferably a compound having an acryloyl group or a methacryloyl group and a monovalent saturated hydrocarbon group. The monovalent saturated hydrocarbon group preferably has 12 to 30 carbon atoms. The monovalent saturated hydrocarbon group may be a chain structure group or a group having a cyclic structure.
As a specific example of (meth) acrylate not containing a fluorine atom, alkyl (meth) acrylate is preferable, and methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) methacrylate, cyclohexyl (meth) ) Acrylate, isobornyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, behenyl (meth) acrylate, stearyl (meth) acrylate It is done.

  The content of polymerized units based on (meth) acrylates not containing fluorine atoms is preferably 10 to 50 mol%, preferably 5 to 40 mol, of all polymerized units (100 mol%) of the fluoropolymer (B). % Is more preferable. When it is within the above range, the coating film is more excellent in water drop sliding property and film forming property.

Examples of other (meth) acrylates not containing a fluorine atom include (meth) acrylates having a crosslinkable group.
Crosslinkable groups are hydroxyl group, isocyanate group, blocked isocyanate group, alkoxysilyl group, amino group, alkoxymethylamide group, silanol group, ammonium group, amide group, epoxy group, oxazoline group, carboxy group, alkenyl group, sulfonic acid Group is preferable, and a hydroxyl group, a blocked isocyanate group, an amino group, or an epoxy group is more preferable.
Specific examples of the (meth) acrylate having a crosslinkable group include N-methylol (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, 3-chloro-2-hydroxypropyl methacrylate, or hydroxy Examples thereof include polycaprolactone esters of ethyl (meth) acrylate (Placcel FA, FM series, manufactured by Daicel Chemical Industries).
The content of the polymerized units based on the (meth) acrylate having a crosslinkable group is preferably 0 to 5 mol% of all the polymerized units (100 mol%) of the fluoropolymer (B), and preferably 1 to 10 mol. % Is more preferable.

  Furthermore, the fluoropolymer (B) may contain polymerized units based on chloroolefins such as vinyl chloride and vinylidene chloride.

  The number average molecular weight (Mn) of the fluoropolymer (B) is preferably from 20,000 to 500,000, more preferably from 30,000 to 200,000. The number average molecular weight (Mn) of the fluoropolymer (B) is a number average molecular weight (Mn) measured by gel permeation chromatography using polystyrene as a standard substance.

  In the water-based coating composition of the present invention, the content of the fluoropolymer (A) is from 75 to 75 with respect to the total mass (100% by mass) of the fluoropolymer (A) and the fluoropolymer (B). It is 99 mass%, and it is preferable that content of a fluoropolymer (B) is 1-25 mass%. That is, it is preferable that the main polymer component constituting the coating film is the fluoropolymer (A). The content of the fluoropolymer (A) is preferably 80 to 95% by mass, and the content of the fluoropolymer (B) is preferably 5 to 20% by mass. When it is within the above range, since the fluoropolymer (B) is easily held in the coating film containing the fluoropolymer (A) as a main component, and on the surface thereof, bleeding out is suppressed. Performance sustainability is improved.

  The water content in the aqueous coating composition of the present invention is selected from the range in which the fluoropolymer (A) particles and the fluoropolymer (B) particles are stably dispersed. 20-90 mass% is preferable with respect to the total mass (100 mass%) of a fluoropolymer (A) and a fluoropolymer (B), and, as for content of water, 40-70 mass% is more preferable.

Furthermore, the water-based coating composition of the present invention includes other components other than the fluorine-containing polymer (A) particles, the fluorine-containing polymer (B) particles, and water as long as the effects of the present invention are not impaired. It may be. Examples of the other components include a surfactant, a crosslinking agent, a film-forming aid, a thickener, an antifoaming agent, a light stabilizer, a design agent, a surface conditioner, an aqueous medium, an antistatic agent, and an antifungal agent. Can be mentioned.
Moreover, it is preferable that the aqueous coating composition of this invention does not contain an organic solvent substantially. The phrase “substantially free of organic solvent” means that the proportion of the organic solvent in the total mass (100% by mass) of the aqueous coating composition is 5% by mass or less, preferably 0.5% by mass or less. , More preferably 0%.

  The method for producing the water-based coating composition of the present invention is not particularly limited, but includes a composition containing the fluoropolymer (A) particles and water, and a composition containing the fluoropolymer (B) particles and water. Can be produced by mixing the product with an arbitrary ratio.

The aqueous coating composition of the present invention is used to form a coating film on the surface of a substrate exposed to below freezing point.
The material of the substrate is not particularly limited, and may be any of metal, resin, rubber, stone, glass, and concrete. Further, the shape and state of the object (that is, the base material) are not particularly limited.
For example, since the coating film of the water-based coating composition of the present invention is excellent in adhesion and followability to a substrate, it can impart an ice / snow adhesion preventing effect to the surface of an elastic substrate. Examples of the material constituting the elastic substrate include soft vinyl chloride resin, soft polyethylene resin, chloroprene rubber, nitrile rubber, ethylene propylene rubber, acrylic rubber, and natural rubber.
The use of the base material is not particularly limited as long as it is an application that is exposed to below freezing point. Specific examples include automobile steel plates, outdoor unit fins, exterior building materials, wiper blades, and electric cables.

The coating film formed using the water-based coating composition of the present invention usually only needs to be formed on the outermost surface exposed to the substrate exposed to below freezing point. That is, the aqueous coating composition of the present invention may be applied directly to the surface of the object, or may be applied to the outermost surface via the undercoat layer. The thickness of the coating film to be formed is not particularly limited and is preferably 10 to 100 μm.
In addition, the method of applying the paint to the base material of the aqueous paint composition of the present invention is not particularly limited, and a coating apparatus such as a brush, roller, dipping, spray, roll coater, die coater, applicator, spin coater or the like is used. The method of using it is mentioned.

As described above, in the present invention, the surface of the substrate exposed to below freezing point includes the particles of the fluoropolymer (A), the particles of the fluoropolymer (B), and water. And forming a coating film of an aqueous coating composition in which the difference between the average particle diameter of the fluoropolymer (A) particles and the average particle diameter of the fluoropolymer (B) particles is 100 nm or less in absolute value. In addition, a method for preventing ice and snow from adhering to the surface of the substrate can also be provided.
Moreover, in this invention, the coating article which has a base material and the coating film arrange | positioned on this base material and formed using the said water-based coating composition can also be provided.
The details of the aqueous coating composition and the substrate are as described above.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

[Raw materials used]
The following raw materials were used (however, -cycloC ₆ H ₁₀ -represents a 1,4-cyclohexylene group).
CTFE: chlorotrifluoroethylene.
CHVE: cyclohexyl vinyl ether.
EVE: ethyl vinyl ether.
2-EHVE: 2-ethylhexyl vinyl ether.
4-HBVE: 4-hydroxybutyl vinyl ether.
_{CHMVE: CH 2 = CHOCH 2 -cycloC} 6 H 10 -CH 2 OH.
_{CM-EOVE: CH 2 = CH} -O-CH 2 -cycloC 6 H 10 -CH 2 -O- (CH 2 CH 2 O) n1 H (n1: 15, average molecular weight: 830, Nippon Emulsifier Co., Ltd..)
_{C6FMA: CH 2 = C (CH} 3) C (O) OCH 2 CH 2 (CF 2) 6 F
Nonionic surfactant: polyoxyethylene alkyl ether (HLB: 13.8).
Anionic surfactant: sodium lauryl sulfate (manufactured by Nikko Chemicals).
Pigment: Titanium oxide (manufactured by Sakai Chemical Industry Co., Ltd., D-918).
Pigment dispersant: Disperbyk (registered trademark) 190 manufactured by Big Chemie.
Antifoaming agent: Dehydran (registered trademark) 1620 manufactured by Cognis.
Surface conditioner: BYK (registered trademark) -348, manufactured by Big Chemie.
Thickener: Vermodol (registered trademark) 215 manufactured by Akzo Nobel.
Water-dispersed isocyanate curing agent: manufactured by Sumika Bayer, Vihijoule (registered trademark) 3100).
Film-forming aid: Trade name “EHG” (manufactured by Nippon Emulsifier Co., Ltd.)

[Aqueous dispersion containing fluoropolymer (A)]
The aqueous dispersion containing the fluorinated polymers (A ¹ ) to (A ³ ) produced in Preparation Examples 1 to ³ , or the vinylidene fluoride homopolymer (A ⁴ ) (fluorine content: 59 mass%) An aqueous dispersion containing 50% by mass (solid content concentration) of particles (average particle size: 160 nm) was used.

[Aqueous dispersion containing fluoropolymer (B)]
An aqueous dispersion containing 30% by mass (solid content concentration) of a fluorine-containing polymer (B ¹ ) containing polymer units based on C6FMA and having a fluorine content of 35% by mass (Asahi Guard Co., Ltd., registered trademark) ) E series.). In the aqueous dispersion, the fluoropolymer (B ¹ ) formed particles having an average particle diameter of 190 nm, and the pH of the aqueous dispersion was 3.0.

<Preparation Example 1> Preparation of aqueous dispersion containing fluoropolymer (A ¹ ) In an autoclave with an internal volume of 2500 mL, water (1280 g), CHVE (415 g), 2-EHVE (230 g), CM-EOVE (21 g) ), CHMVE (34 g), ion exchange water (1280 g), potassium carbonate (3.0 g), ammonium persulfate (5.4 g), nonionic surfactant (33 g), anionic surfactant (1.4 g). The solution was charged, cooled with ice, and pressurized with nitrogen gas to 0.4 MPaG (gauge pressure; the same applies hereinafter) and degassed. After depressurizing and depressurizing twice, the dissolved air was removed, CTFE (580 g) was charged, the reaction was carried out at 50 ° C. for 24 hours, and then the autoclave was cooled with water. Unreacted monomers were purged, and the autoclave content liquid was recovered to obtain an aqueous dispersion containing the fluoropolymer (A ¹ ).
The fluorine-containing polymer (A ¹ ) had a fluorine content of 22% by mass and a hydroxyl value of 10 mgKOH / g. The ratio (molar ratio) of the polymerized units of the fluoropolymer (A ¹ ) was CTFE units / CM-EOVE units / CHMVE units / CHVE units / 2-EHVE units = 50 / 0.25 / 2/33/14. 75.
The fluoropolymer (A ¹ ) forms particles with an average particle diameter of 150 nm in the aqueous dispersion, and the aqueous dispersion contains 50% by mass (solid content concentration) of the fluoropolymer (A ¹ ). It was.

<Preparation Example 2> fluoropolymer ^{(A 2)} to the autoclave Preparation inner volume 2500mL of aqueous dispersion containing water (1280g), EVE (185g) , CHVE (244g), CM-EOVE (47g), CHMVE (194 g), ion-exchanged water (1280 g), potassium carbonate (2.0 g), ammonium persulfate (1.3 g), nonionic surfactant (33 g), anionic surfactant (1.4 g) were charged. The mixture was cooled with ice, pressurized with nitrogen gas to 0.4 MPaG, and deaerated. After depressurization was repeated twice and dissolved air was removed, CTFE (664 g) was charged and reacted at 50 ° C. for 24 hours, and then the autoclave was cooled with water. Unreacted monomers were purged and the autoclave content liquid was recovered to obtain an aqueous dispersion containing the fluoropolymer (A ² ).
The fluorine-containing polymer (A ² ) had a fluorine content of 24% by mass and a hydroxyl value of 55 mgKOH / g. The ratio (molar ratio) of the polymerization units of the fluoropolymer (A ² ) is CTFE units / CM-EOVE units / CHMVE units / EVE units / CHVE units = 50 / 0.5 / 10 / 22.5 / 17. there were. The fluoropolymer (A ² ) forms particles with an average particle diameter of 145 nm in the aqueous dispersion, and the aqueous dispersion contains 50% by mass (solid content concentration) of the fluoropolymer (A ² ). It was.

<Preparation Example 3> Preparation of aqueous dispersion containing fluoropolymer (A ³ ) CTFE units / EVE units / CHVE units / 4-HBVE units in this order at a ratio (molar ratio) of 50/15/15/20 The fluorine-containing polymer (hydroxyl value: 100 mgKOH / g, mass average molecular weight: 7000) contained in was dissolved in methyl ethyl ketone to obtain a varnish containing 60% by mass of the fluorine-containing polymer.
To 300 g of the varnish, succinic anhydride (4.8 g) and triethylamine (0.072 g) were added and reacted at 70 ° C. for 6 hours to carry out an esterification reaction. As a result of infrared absorption spectrum analysis of the solution after the reaction, the characteristic absorption (1850 cm ⁻¹ , 1780 cm ⁻¹ ) of succinic anhydride disappeared, and the carboxy group (1710 cm ⁻¹ ) and ester group (1735 cm ⁻¹ ) Absorption was newly observed, and production of a fluorinated polymer having a carboxy group (hydroxyl value: 85 mg / KOH, acid value: 15 mgKOH / g) was confirmed.
Triethylamine (4.9 g) was added to the solution after the reaction, and after stirring at 25 ° C. for 20 minutes, ion-exchanged water (180 g) was gradually added. Next, acetone and methyl ethyl ketone in the solution are distilled off under reduced pressure, and ion-exchanged water is added to contain 50% by mass (solid content concentration) of the fluorinated polymer (A ³ ) substantially free of an organic solvent. An aqueous dispersion was obtained.
The fluoropolymer (A ³ ) has a fluorine content of 17% by mass, and the ratio (molar ratio) of the polymer units of the fluoropolymer (A ³ ) is CTFE units / EVE units / CHVE units / 4-HBVE. Unit / 4-HBVE unit esterified with succinic anhydride = 50/15/15/17/3. In addition, the ratio of the carboxy group neutralized with triethylamine among the carboxy groups of the esterified 4-HBVE unit was 70 mol%. The fluoropolymer (A ³ ) forms particles with an average particle diameter of 80 nm in the aqueous dispersion, and the aqueous dispersion contains 50% by mass (solid content concentration) of the fluoropolymer (A ³ ). It was.

<Preparation Example 4> Preparation of pigment composition Pigment (210 parts by mass), pigment dispersant (21 parts by mass), antifoaming agent (4.5 parts by mass), ion-exchanged water (64.5 parts by mass), and glass After a mixed solution of beads (300 parts by mass) was dispersed using a disperser, glass beads were removed by filtration to prepare a pigment composition.

<Example 1> Preparation pigment composition of the aqueous coating composition (1) to (55 g), aqueous dispersion containing the fluoropolymer ^{(A 1)} (193 g), coalescent (15 g), thickening An aqueous coating composition (1) was prepared by mixing an agent (0.5 g) and an aqueous dispersion (15 g) containing a fluoropolymer (B ¹ ).
The aqueous coating composition (1) is applied to the surface of an aluminum plate (thickness 1 mm) whose surface is chromated using a film applicator so that the dry film thickness is 40 μm, and the temperature is 23 ° C. and the humidity is 50%. Were dried for 2 weeks to prepare an aluminum test piece having a coating film formed from an aqueous coating composition on the surface. The evaluation results of the test pieces are shown in Table 1.

<Example 2> Preparation example of water-based coating composition (2) To the pigment composition (55 g), a fluoropolymer (A ² ) (193 g), a film-forming aid (15 g), a thickener (0.5 g) ), An aqueous dispersion (15 g) containing the fluoropolymer (B ¹ ), and an aqueous dispersion isocyanate curing agent (22.9 g) were mixed to prepare an aqueous coating composition (2).
In the same manner as in Example 1, aluminum test pieces were produced. Table 1 shows the evaluation results of the test pieces.

<Example 3> Preparation example of aqueous coating composition (3) To 55 g of the pigment composition, a fluoropolymer (A ³ ) (193 g), a surface conditioner (1.3 g), a thickener (0.5 g). ), An aqueous dispersion (15 g) containing the fluoropolymer (B ¹ ), and an aqueous dispersion type isocyanate curing agent (25 g) were mixed to prepare an aqueous coating composition (3).
In the same manner as in Example 1, aluminum test pieces were produced. Table 1 shows the evaluation results of the test pieces.

<Example 4> Preparation example of water-based coating composition (4) In the pigment composition (55 g), an aqueous dispersion of a fluoropolymer (manufactured by Arkema, product name “Kynar Aquatec FMA-12”, particle size: 160 nm) ) (193 g), a film-forming aid (15 g), a thickener (0.5 g), and an aqueous dispersion (15 g) containing a fluoropolymer (B ¹ ) are added and mixed to form an aqueous coating composition (4 ) Was prepared.
Here, “Kynar Aquatec FMA-12 (manufactured by Arkema)”, which is an aqueous dispersion of a fluoropolymer, has a composite particle of PVDF (polyvinylidene fluoride) and an acrylic resin (a fluoropolymer) in water. It is dispersed, the mass ratio of PVDF to acrylic resin is 50:50, and the solid content concentration is 46 mass%.
Moreover, the fluorine content of the fluoropolymer contained in “Kynar Aquatec FMA-12 (manufactured by Arkema)” is 59% by mass.
In the same manner as in Example 1, aluminum test pieces were produced. The evaluation results of the test pieces are shown in Table 1.

<Comparative example 1> Preparation example of water-based coating composition (5) A water-based coating composition (5) is prepared in the same manner as in Example 1 except that the aqueous dispersion containing the fluoropolymer (B ¹ ) is not used. did.

<Evaluation example> Evaluation example of water-based coating composition Using the prepared water-based coating composition, the ice and snow adhesion effect of the coating film was evaluated by the following method.
(Water contact angle of coating film)
A drop of water was dropped on the surface of the coating film in the air, and the contact angle of the water was measured with a contact angle meter (Kyowa Interface Science Co., Ltd., CA-X type). It shows that water repellency is so high that the contact angle of water is large.
(Ice adhesion)
Drop 1 ml of water droplets on the surface of the coating with a dropper and hold at -15 ° C for 24 hours, then leave it at 25 ° C for 3 minutes, then wipe the ice on the surface of the coating with Kimwipe. The adhesion of ice was evaluated according to the wiping standard.
○: The ice could be removed by lightly wiping.
X: The ice could not be removed only by wiping lightly.

Each of the aqueous coating compositions (1) to (5) is applied to the surface of a chromate-treated aluminum plate (thickness: 1 mm) using a film applicator so as to have a dry film thickness of 40 μm. Aluminum test pieces each having a coating film formed using the aqueous coating compositions (1) to (5) on the surface were prepared by drying for 2 weeks at 23 ° C. and 50% humidity.
Table 1 summarizes the evaluation results of the test pieces.

[Evaluation results]
As shown in Table 1, the absolute difference between the average particle size of the fluoropolymer (A) particles contained in the aqueous coating composition and the average particle size of the fluoropolymer (B) particles is 100 nm or less. It was shown that a coating film for preventing the adhesion of snow and ice can be formed on the surface of the substrate exposed to below freezing point (Example).

Claims (5)

It is a water-based paint composition for forming a coating film that prevents ice and snow adhesion on the surface of a substrate exposed to below freezing point,
Particles of a fluoropolymer (A) containing a polymer unit based on a fluoroolefin and having a carbon atom-hydrogen atom bond;
Particles of a fluoropolymer (B) comprising polymerized units based on (meth) acrylate having a polyfluoroalkyl group;
Including water,
The water-based coating composition in which the difference between the average particle size of the particles of the fluoropolymer (A) and the average particle size of the particles of the fluoropolymer (B) is 100 nm or less in absolute value.   The water-based paint composition according to claim 1, wherein the difference between the fluorine content of the fluoropolymer (A) and the fluorine content of the fluoropolymer (B) is 30% by mass or less in absolute value. .   Content of the said fluoropolymer (A) is 75-99 mass% with respect to the total mass of the said fluoropolymer (A) and the said fluoropolymer (B), The said fluoropolymer The water-based coating composition of Claim 1 or 2 whose content of (B) is 1-25 mass%.   The coated article which has a base material and the coating film which is arrange | positioned on the said base material and was formed using the aqueous coating composition of any one of Claims 1-3. On the surface of the substrate exposed to below freezing point,
Particles of a fluoropolymer (A) containing a polymer unit based on a fluoroolefin and having a carbon atom-hydrogen atom bond;
Particles of a fluoropolymer (B) comprising polymerized units based on (meth) acrylate having a polyfluoroalkyl group;
Including water,
A coating film of an aqueous coating composition in which the difference between the average particle diameter of the fluoropolymer (A) particles and the average particle diameter of the fluoropolymer (B) particles is 100 nm or less is formed. And the method of preventing the snow and ice adhesion to the surface of a base material.