JP2017203105A - Coating Composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition capable of forming a coating film on a metal roof surface, the coating film being hardly peeled therefrom with snow and ice even when removing snow.SOLUTION: A coating composition for a metal roof includes a modified copolymer resin (A) and a modified fluoroethylene composition (B). The modified copolymer resin (A) has an oxidative polymerization group and a structure derived from a (meth)acrylic copolymer. The modified fluoroethylene composition (B) has weight average molecular weight of 10,000 or more and less than 100,000. With regard to a total solid content 100 pts.mass of the modified copolymer resin (A), a solid content of modified fluoroethylene composition (B) is 1-20 pts.mass.SELECTED DRAWING: None

Description

  The present invention relates to a coating composition.

  Conventionally, the coating composition used in order to coat | cover the surface of a metal base material is known. Such a coating composition is used, for example, to provide a rust prevention property or the like by covering the metal roof surface of a building such as a house and to improve the aesthetic appearance.

  By the way, in a snowfall area, snow falls on the roof of a building such as a house in winter. If the snowfall continues and the snow continues to accumulate on the roof, it is necessary to remove the snow that has accumulated on the roof because the building may collapse due to the weight of the snow. The snow removal of the roof is performed by dropping the snow accumulated on the roof under the roof by human power or the like.

  However, if the snowfall continues, the snow piled up on the roof will freeze and freeze at the interface with the roof, and the snow surface will strongly press the ice and snow present at the interface with the weight of the snow. In such a case, there is a possibility that the coating film formed on the roof surface may be peeled off along with snow and ice during snow removal. The roof from which the coating film is peeled not only impairs the beauty, but also has a problem because corrosion due to exposure of the metal substrate is likely to occur.

  In order to cope with such a problem, it is conceivable to form a coating film for preventing snow and icing on the metal roof surface of a building such as a house. As a technique relating to such a coating film that prevents snow and icing, for example, a coating film that exhibits anti-icing performance by blending a specific amount of a fluorinated aromatic compound in an organic solvent type synthetic resin coating composition. A coating composition that can be formed is known (for example, see Patent Document 1 described below).

  Moreover, the coating composition containing the fluorine-containing copolymer which has a silyl group which gives the coating film excellent in coating-film performances, such as anti-icing property, is known (for example, refer patent document 2 mentioned later). .

Japanese Patent Application Laid-Open No. 5-239382 JP-A-5-017535

  However, although the coating film formed by the coating composition described in Patent Documents 1 and 2 has a function of preventing snow and icing, in practice, when snowfall continues, It is impossible to avoid the situation where snow falls on the roof. Therefore, when the coating film and the ice and snow are pressure-bonded, the coating film can be peeled off together with the ice and snow at the time of snow removal. Therefore, at present, the technology that focuses on such a problem has not been sufficiently studied.

  The present invention has been made in view of the above, and an object of the present invention is to provide a coating composition that can form a coating film on the surface of a metal roof that is difficult to peel off with snow and ice even during snow removal.

  In order to achieve the above object, the present invention provides a coating composition for metal roof, comprising a modified copolymer resin (A) and a modified fluorinated ethylene composition (B), wherein the modified copolymer The coalesced resin (A) is a modified copolymer resin having an oxidation polymerizable group and having a structure derived from a (meth) acrylic copolymer, and the modified fluorinated ethylene composition (B) has a weight average molecular weight. Is from 10,000 to less than 100,000, and the solid content of the modified fluorinated ethylene composition (B) is from 1 to 20 with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A). Provided is a coating composition which is a coating composition in parts by mass.

  The modified copolymer resin (A) includes a modified copolymer resin (A-1) obtained by a reaction between a (meth) acrylic resin and an alkyd resin, and an alkyd resin having a reactive vinyl group and an oxidative polymerizable group. A copolymer resin (A-2) obtained by a polymerization reaction with a copolymer resin (A-) obtained by a polymerization reaction between a reactive vinyl group having an oxidatively polymerizable group and another reactive vinyl group. 3) and a modified copolymer resin (A-4) obtained by a polymerization reaction of a copolymer of a reactive vinyl group having a glycidyl group and an unsaturated fatty acid capable of oxidative polymerization, at least selected from the group consisting of It is preferable that 1 type is included.

  It is preferable that the modified copolymer resin (A) is further modified with silicone.

  The modified fluorinated ethylene composition (B) is preferably weakly solubilized and modified.

  It is preferable that the solid content of the modified ethylene fluoride ethylene composition (B) is 2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A).

  Furthermore, it is preferable to include polyisocyanate (C) and a silane coupling agent (D) having two different functional groups in the same molecule.

  The coating film formed from the coating composition is a DuPont impact-shaped jig (diameter = 12.7 mm, weight weight 300 g) with an ice film having a thickness of 1 mm formed on the coating film. In an impact test conducted in accordance with JIS K 5600-5-3, the initial impact value is preferably 200 mm or more.

  ADVANTAGE OF THE INVENTION According to this invention, the coating composition which can form the coating film which is hard to peel with snow and ice at the time of snow removal on a metal roof surface can be provided.

Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited to the following embodiment.
The coating composition according to this embodiment is used to form a coating film that covers the surface of a metal substrate. Although the metal base material in this embodiment is not specifically limited, The metal base material arrange | positioned in the structure installed outdoors, for example, the metal roof of buildings, such as a house, is mentioned. Such a metal roof is not particularly limited, and examples thereof include a tin roof and a steel plate roof.

  In addition, a coating film may be directly formed on the metal roof with the coating composition according to the present embodiment, but the coating composition according to the present embodiment is a metal on which a coating composition has already been formed. It is preferably used for repainting the coating film when refurbishing the roof. In such a case, the coating composition according to the present embodiment may be applied onto the coating film already formed on the metal roof. The coating composition according to the present embodiment can be used as a one-component paint or a two-component paint using polyisocyanate (C) as a curing agent, and is cured by drying at room temperature. It is easy to use in the repainting application of the coating film and is preferably used.

  The coating composition according to this embodiment includes a modified copolymer resin (A) and a modified fluorinated ethylene composition (B), and also a polyisocyanate (C) and a silane coupling agent (D). And a reinforcing agent consisting of:

<Modified copolymer resin (A)>
The modified copolymer resin (A) is a modified copolymer resin having an oxidation polymerizable group and having a structure derived from a (meth) acrylic copolymer. Such a modified copolymer resin (A) preferably contains at least one of the modified copolymer resins (A-1) to (A-4) described below.

<Modified copolymer resin (A-1)>
The modified copolymer resin (A-1) is obtained by a polymerization reaction between a (meth) acrylic resin and an alkyd resin.
As said (meth) acrylic resin, the copolymer of the polymerizable unsaturated monomer containing an acrylic monomer can be mentioned.
Examples of the polymerizable unsaturated monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, ( Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, glycidyl (meth) acrylate C1-C24 alkyl esters of acrylic acid or methacrylic acid such as cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate , 2-hydroxybutyl (meth) acrylate, 3 Hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate Hydroxyl-containing monomers such as α, β-ethylenically unsaturated carboxylic acid ester having an alkylene oxide chain and a hydroxyl group such as: isobornyl (meth) acrylate, 1,2,2,6,6-pentamethyl (meth) acrylate Piperidyl, 2,2,6,6-tetramethylpiperidinyl (meth) acrylate, 2- (2′-hydroxy-5′-methacryloxyphenyl) -2H-benzotriazole, styrene, α-methylstyrene, p-methylstyrene, p-tert-butyl Vinyl aromatic hydrocarbon monomers such as tylene and p-chlorostyrene, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl toluene, etc. Monofunctional vinyl group-containing monomers, bifunctional vinyl group-containing monomers such as divinylbenzene and diethylene glycol (meth) acrylate, monomers having three or more reactive vinyl groups, polymers composed of one or more of these, and the like Can be mentioned.

  The alkyd resin has an unsaturated carbon bond (carbon double bond or carbon triple bond). As the unsaturated fatty acid introduced into the alkyd resin, those having a high solid iodine value, that is, having many unsaturated carbon bonds are preferable. Examples of such unsaturated fatty acids include dry oil fatty acids and semi-dry oil fatty acids. Although dry oil fatty acids and semi-dry oil fatty acids are not strictly distinguishable, usually dry oil fatty acids are unsaturated fatty acids having a solid iodine value of 130 or more, and semi-dry oil fatty acids have a solid iodine value of 100 or more and Less than 130 unsaturated fatty acids. The non-drying oil fatty acid is usually a fatty acid having a solid iodine value of less than 100. Examples of the dry oil fatty acid and semi-dry oil fatty acid include fish oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, poppy oil fatty acid, eno oil fatty acid, hemp oil fatty acid, grape Examples include nuclear oil fatty acid, corn oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid, hyogenic acid fatty acid and the like. These dry oil fatty acids and semi-dry oil fatty acids may be non-dry oil fatty acids (for example, coconut oil fatty acid, hydrogenated coconut oil fatty acid, palm oil fatty acid, etc.), caproic acid, capric acid, lauric acid, myristic acid as necessary. , Palmitic acid, stearic acid and the like may be used in combination. Furthermore, in this embodiment, you may introduce fats and oils (glyceride) into an alkyd resin with an unsaturated fatty acid or instead of an unsaturated fatty acid. Such fats and oils are those having unsaturated carbon bonds, such as fish oil, dehydrated castor oil, safflower oil, linseed oil, soybean oil, sesame oil, poppy oil, eno oil, hemp seed oil, grape kernel oil. Corn oil, tall oil, sunflower oil, cottonseed oil, walnut oil, rubber seed oil and the like. The unsaturated fatty acid is a fatty acid having an oxidatively curing type polymerizable unsaturated group, and imparts an oxidizable polymerizable group to the alkyd resin.

<Modified copolymer resin (A-2)>
The modified copolymer resin (A-2) is obtained by a polymerization reaction of an alkyd resin having a reactive vinyl group and an oxidative polymerizable group.
Examples of the compound having a reactive vinyl group include the (meth) acrylic resin used in the above (A-1).

  As for the alkyd resin which has the said oxidation polymerizable group, the alkyd resin used for said (A-1) is mentioned.

<Modified copolymer resin (A-3)>
The modified copolymer resin (A-3) is obtained by a polymerization reaction between a reactive vinyl group having an oxidatively polymerizable group and other reactive vinyl groups.
Examples of the compound having a reactive vinyl group include (meth) acrylic monomers, vinyl aromatic hydrocarbon monomers, 1 to 3 functional vinyl group-containing monomers, and polymers thereof as described above.
The reactive vinyl group having an oxidatively polymerizable group can be obtained, for example, by introducing the unsaturated fatty acid described above into the compound having the reactive vinyl group described above.

<Modified copolymer resin (A-4)>
The modified copolymer resin (A-4) is obtained by a polymerization reaction between a reactive vinyl group copolymer having a glycidyl group and an oxidatively polymerizable unsaturated fatty acid.
The copolymer of the reactive vinyl group having the glycidyl group is, for example, an acrylic monomer having a glycidyl group such as glycidyl (meth) acrylate, a vinyl aromatic hydrocarbon monomer having an epoxy group, or a 1-3 functional vinyl group. It is obtained by copolymerizing the containing monomer.

  Examples of the oxidatively polymerizable unsaturated fatty acid (hereinafter sometimes simply referred to as “unsaturated fatty acid”) include the unsaturated fatty acids described above.

Moreover, it is preferable that the modified copolymer resin (A) according to the present embodiment is further modified with silicone.
The silicone-modified modified copolymer resin (A) can be obtained, for example, by reacting the modified copolymer resin (A) with silicone having at least one of a hydroxyl group and an alkoxysilyl group.

  Silicone having at least one of a hydroxyl group and an alkoxysilyl group (hereinafter sometimes simply referred to as “silicone”) has, for example, a siloxane bond (—Si—O—Si—) as a main chain and an alkyl group in a side chain, It is a polysiloxane having a branched structure in which substituents such as an aryl group, a hydroxyl group, an alkoxy group, and an alkoxysilyl group are present. The silicone used in the present embodiment is not particularly limited as long as it is a silicone having at least one of a hydroxyl group and an alkoxysilyl group. It is preferable that at least one of the hydroxyl group or the alkoxysilyl group is directly bonded to at least one silicon atom in the silicone molecule.

The structure of silicone is, for example, a structure represented by the following formula (1).
[Chemical 1]
R ¹ _o (R ² O) _p (SiO) _n Si (1)

Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 12 carbon atoms, o is 2 or more, p satisfies 1 ≦ p <2n).
Since silicone is a mixture of molecules having different degrees of polymerization and functional group substitution, the values of m and n in the above formula are not necessarily integers.

  As the silicone, a silicone further having a phenyl group in addition to a hydroxyl group or an alkoxysilyl group is preferable, and the phenyl group is more preferably directly bonded to a silicon atom. When silicone having a phenyl group is used, solubility in a solvent (particularly a weak solvent described later) is further increased. As a result, since the viscosity of the paint can be lowered appropriately, workability can be further improved. Further, since the refractive index of the coating film is improved, the initial gloss value is improved. Furthermore, a silicone having an alkyl group is preferable, and the alkyl group is more preferably directly bonded to a silicon atom. Silicone (a-4) having a phenyl group directly bonded to a silicon atom and a propyl group (n-propyl group or isopropyl group) bonded directly to a silicon atom is particularly preferable.

The molecular weight of silicone is not particularly limited. In the present embodiment, a silicone having a number average molecular weight of preferably 200 to 5,500, more preferably a silicone having a number average molecular weight of 1,400 to 3,000 is used.
Typical examples of such commercially available silicones include 3037 INTERMEDIATE, 3074 INTERMEDIATE, Z-6018, 217 FLAKE, 220 FLAKE, 233 FLAKE, 249 FLAKE, QP8-5314, SR2402, AY 42-163 (all of which are Toray TSR160, TSR165, TSR3168 (all manufactured by Momentive Performance Materials); KR-211, KR-216, KR-213, KR-9218 (all manufactured by Shin-Etsu Chemical Co., Ltd.) SILRES SY 231, SILRES SY 300, SILRES SY 409, SILRES IC 368 (all manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) and the like.

  Moreover, in the modified copolymer resin (A) according to the present embodiment, when a copolymer is obtained with an unsaturated fatty acid, an alkyd resin, and a (meth) acrylic resin, the copolymerization ratio is determined by the copolymer obtained. From the viewpoint of solubility in a solvent and the like, the total of unsaturated fatty acids and alkyd resins is preferably 3 to 70% by mass, and (meth) acrylic resin is preferably 30 to 97% by mass. Moreover, it is more preferable that the sum total of unsaturated fatty acid and alkyd resin is 5 to 40 weight%, and (meth) acrylic resin is 60 to 95 mass%.

  Moreover, when using a hydroxyl-containing monomer as a monomer of the (meth) acrylic resin in the modified copolymer resin (A) according to the present embodiment, gelation in the reaction of the unsaturated fatty acid or alkyd resin with the (meth) acrylic resin In addition, the amount of the hydroxyl group-containing monomer should be determined so that gelation does not occur during the reaction with silicone. Usually, it is preferable that the usage-amount of a hydroxyl-containing monomer is 50 mass% or less in the total mass of the unsaturated fatty acid used as the raw material of a copolymer, alkyd resin, and (meth) acrylic resin.

  The copolymerization method for obtaining the modified copolymer resin (A) according to this embodiment is not particularly limited, but the reaction of unsaturated fatty acid or alkyd resin, (meth) acrylic resin, and silicone. From the viewpoint of easiness of application, etc., a solution polymerization method which is performed in an organic solvent in the presence of a radical polymerization initiator is preferred.

  Examples of the radical polymerization initiator used in the synthesis by the solution polymerization include azo series such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile). Polymerization initiators: peroxide polymerization initiators such as lauryl peroxide, t-butylperoxy-2-ethylhexanoate, and benzoyl peroxide can be used.

  Examples of the organic solvent used in the synthesis by solution polymerization include aliphatic hydrocarbon solvents such as n-hexane, n-octane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexane, and methylcyclohexane. Aromatic hydrocarbon solvents such as benzene, toluene, xylene and ethylbenzene; mineral spirits, "Swazole 1000" (manufactured by Cosmo Oil Co., Ltd.), petroleum ethers such as petroleum ether, petroleum benzine and petroleum naphtha; methyl isobutyl ketone, etc. Ketone solvents; ester solvents such as isobutyl acetate; alcohol solvents such as isopropanol; These may be used alone or in admixture of two or more as required.

  A compound having a reactive vinyl group, such as an unsaturated fatty acid, an alkyd resin, or a (meth) acrylic resin, and a silicone for producing a copolymer contained in the modified copolymer resin (A) according to this embodiment The reaction sequence is not particularly limited. However, it should be determined carefully based on the radical polymerizability of the oxidative polymerizable group and the reactivity of the fatty acid. For example, a method of obtaining a silicone-modified copolymer by reacting an oxidatively curable (meth) acrylic copolymer with silicone is preferable from the viewpoint of easy control of the reaction.

  The reaction between the unsaturated fatty acid or alkyd resin and the (meth) acrylic resin is an esterification reaction between a hydroxyl group in the unsaturated fatty acid or alkyd resin and a carboxyl group in the (meth) acrylic resin, or in the alkyd resin. This is based on an esterification reaction between a carboxyl group and a glycidyl group or a hydroxyl group in the (meth) acrylic resin. In this reaction, a reaction catalyst such as a tertiary amine such as N, N-dimethylaminoethanol; a quaternary ammonium salt such as tetrabutylammonium bromide can be used as necessary. When using a reaction catalyst, the amount used is suitably within the range of 0.01 to 100 parts by mass with respect to 100 parts by mass in total of unsaturated fatty acid, alkyd resin and (meth) acrylic resin.

  The reaction conditions of the unsaturated fatty acid or alkyd resin and the (meth) acrylic resin are the same as the unsaturated fatty acid or alkyd resin and the carboxyl group in the (meth) acrylic resin without causing a reaction problem such as gelation. Any conditions may be used as long as they can be reacted. Usually, it is suitable to make it react on the conditions heated at 100-170 degreeC for 2 to 10 hours.

  Reaction of the unsaturated fatty acid or alkyd resin with a (meth) acrylic monomer and a (meth) acrylic resin obtained therefrom, or a compound having a reactive vinyl group having an oxidative polymerizable group, and other reactions An oxidatively curable acrylic copolymer can be obtained by polymerizing a compound having a functional vinyl group. The method of reacting silicone with the oxidatively curable (meth) acrylic copolymer is mainly carried out by heating in the presence of a reaction catalyst as necessary to cause dehydration or dealcohol condensation reaction. Other methods are also acceptable. The dehydration or dealcoholization condensation reaction is based on a reaction between a hydroxyl group or a carboxyl group in the oxidation-curable (meth) acrylic copolymer and a hydroxyl group or an alkoxysilyl group in the silicone. The hydroxyl group or carboxyl group in the modified copolymer resin (A) includes a hydroxyl group initially present in the unsaturated fatty acid or alkyd resin, a carboxyl group and hydroxyl group initially present in the (meth) acrylic resin, and unsaturated. There is a hydroxyl group or a carboxyl group generated by a reaction between at least one of a fatty acid and an alkyd resin and a (meth) acrylic resin.

  As a reaction catalyst in the dehydration and dealcoholization condensation reaction, a metal alkoxide compound, a metal chelate compound, a metal ester compound, or the like is used. Examples of the metal alkoxide compound include aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide, aluminum tri-sec-butoxide, Aluminum alkoxide such as aluminum tri-tert-butoxide; tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-tert-butyl titanate, tetra-n -Titanium alkoxides such as hexyl titanate, tetraisooctyl titanate, tetra-n-lauryl titanate; Til zirconate, tetra-n-propyl zirconate, tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-sec-butyl zirconate, tetra-tert-butyl zirconate, tetra-n-pentyl zirconate, tetra-tert -Zirconium alkoxides such as pentyl zirconate, tetra-tert-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate, tetra-n-stearyl zirconate; dibutyltin dibutoxide, etc., metal Examples of the chelate compound include tris (ethyl acetoacetate) aluminum, tris (n-propyl acetoacetate) aluminum, tris (isopropyl acetoacetate) aluminum, (N-butylacetoacetate) aluminum, isopropoxybis (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, tris (proponylacetonato) aluminum, diisopropoxypropionylacetonatoaluminum, acetylacetonatobis ( Propionylacetonato) aluminum, monoethylacetoacetate bis (acetylacetonato) aluminum, acetylacetonatoaluminum disec-butyrate, methylacetoacetate aluminum ditert-butyrate, bis (acetylacetonato) aluminum monosec- Aluminum chelate compounds such as butyrate, di (methylacetoacetate) aluminum mono-tert-butyrate; diisopropoxy Titanium chelate compounds such as bis (ethylacetoacetate) titanate, diisopropoxy bis (acetylacetonato) titanate, di-n-butoxy bis (acetylacetonato) titanate; tetrakis (acetylacetonato) zirconium, tetrakis (n- Zirconium chelate compounds such as propylacetoacetate) zirconium and tetrakis (ethylacetoacetate) zirconium; dibutyltin bis (acetylacetonate) and the like. Examples of metal ester compounds include dibutyltin diacetate and dibutyltin di (2 -Ethylhexylate), dibenzyltin di (2-ethylhexylate), dibutyltin dilaurate, dibutyltin diisooctyl maleate, and the like. These reaction catalysts can be used alone or in combination of two or more.

  The reaction catalyst is preferably used in an amount of 0.001 to 5 parts by mass with respect to a total of 100 parts by mass of the oxidatively curable acrylic copolymer and silicone, and 0.005 to 1 parts by mass, from the viewpoint of the effect of promoting the reaction. More preferably, it is used.

  The above unsaturated fatty acid or alkyd resin, a (meth) acrylic monomer, and a (meth) acrylic resin obtained therefrom are reacted, or a compound having a reactive vinyl group having an oxidatively polymerizable group, Conditions for allowing silicone to react with an oxidatively curable (meth) acrylic copolymer obtained by polymerizing a compound having a reactive vinyl group are particularly limited as long as dehydration and dealcohol condensation reactions proceed. It is not a thing. Usually, the reaction temperature is 60 to 250 ° C., preferably 80 to 200 ° C., more preferably 100 to 180 ° C., and the reaction time is 0.5 to 24 hours, preferably 1 to 12 hours. Moreover, in the said reaction, reaction can be advanced smoothly by removing the water and alcohol which are produced | generated by reaction from a system.

  In the above reaction, the dehydration and dealcohol condensation reaction may proceed until the obtained resin can exhibit the performance as a coating resin. A hydroxyl group or a part of the carboxylic acid may be reacted, or substantially All of the hydroxyl groups may be reacted. The degree of progress of the reaction is determined by a method for obtaining an absorption intensity caused by a hydroxyl group or a carboxylic acid by infrared absorption spectrum (IR) measurement, a method for measuring the amount of water and alcohol produced by the reaction, a method for measuring an increase in the viscosity of the system, etc. You can know more.

  The modified copolymer resin (A) of the present embodiment preferably has a solid iodine value of 5 to 80. When the solid iodine value is in such a range, the obtained coating film has good water resistance and alkali resistance in addition to weather resistance, and good strength and fleshiness. Furthermore, it hardly causes gelation during the production of the copolymer, and the solubility in a weak solvent is hardly lowered. The modified copolymer resin (A) of the present embodiment preferably has a solid iodine value of 20 to 60. The solid iodine value can be measured according to JIS K 0070 (Testing method for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponified product of chemical products).

  Furthermore, the weight average molecular weight of the modified copolymer resin (A) is preferably 10,000 to 150,000. When the weight average molecular weight of the modified copolymer resin (A) belongs to such a range, the obtained coating film has good water resistance and alkali resistance in addition to weather resistance, and more gloss can be obtained. . Furthermore, the viscosity of the paint does not become too high, and the workability during coating becomes better. The weight average molecular weight of the modified copolymer resin (A) is more preferably 20,000 to 100,000, still more preferably 30,000 to 80,000. The weight average molecular weight is measured by, for example, gel permeation chromatography (GPC).

<Modified fluorinated ethylene composition (B)>
The modified fluorinated ethylene composition (B) is an ethylene copolymer containing fluorine in the structure. The modified fluorinated ethylene composition (B) is preferably solubilized and modified with a weak solvent. Such a copolymer can be obtained, for example, by copolymerizing fluoroethylene with a weak ether-solubilized and modified vinyl ether.

  Specifically, weak solvent solubilization modification means having a plurality of alkyl groups having an average carbon number of 5 or more in one molecule. The plurality of alkyl groups having an average carbon number of 5 or more may be an aliphatic hydrocarbon group or an alicyclic hydrocarbon group. When the modified fluorinated ethylene composition (B) has a plurality of alkyl groups having an average carbon number of 5 or more, the solubility of the modified fluorinated ethylene composition (B) in a weak solvent is improved.

In this embodiment, the weight average molecular weight of the modified fluorinated ethylene composition (B) is 10,000 or more and less than 100,000.
When considering the formation of a coating film on which ice and snow are difficult to adhere to the surface, a high water repellency can be imparted to the coating film by setting the weight average molecular weight of the modified fluorinated ethylene composition to 10,000 or less, and the adhesion force at the interface is reduced. Since it falls, it is preferable. However, the modified fluorinated ethylene composition (B) in the present embodiment has a weight average molecular weight of 10,000 or more, and the modified fluorinated ethylene composition (B) has a weight average molecular weight of 10,000 or more. A strong coating film can be formed, and even if ice and snow adhere to the surface, it is possible to form a coating film that is difficult to peel off with ice and snow. In addition, by making the weight average molecular weight of the modified fluorinated ethylene composition (B) less than 100,000, the adhesion between the coating film and the ice and snow can be reduced, and even with an impact during snow removal, it is difficult to peel off with the ice and snow. A coating film can be formed. The weight average molecular weight is measured by, for example, gel permeation chromatography (GPC).

  In the coating composition according to this embodiment, the content of the modified fluorinated ethylene composition (B) is 1 to 20 parts by mass with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A). is there. When the content of the modified fluorinated ethylene composition (B) in the coating composition is 1 part by mass or more, the adhesion between the coating film and ice and snow can be reduced. Moreover, a coating film with high adhesiveness with a base material can be formed because content of a modified | denatured ethylene fluoride composition (B) is 20 mass parts or less. That is, when the content of the modified fluorinated ethylene composition (B) is within the above range, it is possible to form a coating film that is difficult to peel off with snow and ice by the coating composition according to this embodiment. The content of the modified fluorinated ethylene composition (B) is preferably 2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A).

  Typical commercial products of such a modified fluorinated ethylene composition (B) include Lumiflon LF-200, Lumiflon LF-400, Lumiflon LF-800 (all manufactured by Asahi Glass Co., Ltd.) and the like.

<Polyisocyanate (C)>
The polyisocyanate (C) is not particularly limited as long as it has two or more isocyanate groups in the molecule. Examples of the polyisocyanate (C) include low-molecular-weight polyisocyanates such as aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates, prepolymers of these polyisocyanates, isocyanurates of these polyisocyanates, and the like. And trione derivatives of these polyisocyanates and derivatives and modified products of these polyisocyanates.

  “Polyisocyanate” is a general term for compounds having a plurality of isocyanate groups in the molecule, and low molecular polyisocyanates such as diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and derivatives obtained from these polyisocyanates, Includes modified products, prepolymers and the like. The “polyisocyanate derivative” is a general term for compounds obtained from low-molecular polyisocyanates, and includes modified products, prepolymers, and the like. The “polyisocyanate modified product” means a reaction product obtained by modifying a low molecular polyisocyanate or a prepolymer.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, 1,2-propylene diisocyanate, tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, hexamethylene diisocyanate, and pentane. Aliphatic diisocyanates such as methylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, lysine ester triisocyanate, 1,4,8-triisocyanatooctane, 1,6,11-tri Isocyanatoundecane, 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, 2,5,7-trimethyl-1,8-diisocyanato-5-i Cyanatophenyl include aliphatic polyisocyanates methyl octane.

  Examples of the alicyclic polyisocyanate include 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate). ), 4,4′-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane Cyclic diisocyanates such as 1,3,5-triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, 2- (3-isocyanatopropyl) -2,5-di (isocyanate) Tomethyl) -bicyclo [2.2.1] heptane, 2- (3-isocyanatopropyl) -2,6-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 3- (3-isocyanate Natopropyl) -2,5-di (isocyanatomethyl) -bicyclo [2.2.1] heptane, 5- (2-isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -Bicyclo [2.2.1] heptane, 6- (2-isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo [2.2.1] heptane, 5- ( 2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo [2.2.1] -heptane, 6- (2-isocyanatoethyl) -2-isocyanatomethi 2- (3-isocyanatopropyl) - bicyclo [2.2.1], and aromatic polyisocyanates such as heptane.

  Aromatic polyisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 2,4′- or 4,4′-diphenylmethane diisocyanate or mixtures thereof. , 4- or 2,6-tolylene diisocyanate or mixtures thereof, aromatic diisocyanates such as 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and triphenylmethane-4,4 ', 4' '- Aromatic polyisocyanates such as triisocyanate, 1,3,5-triisocyanatebenzene, 2,4,6-triisocyanatetoluene, 4,4′-diphenylmethane-2,2 ′, 5,5′-tetraisocyanate It is below.

  Examples of the polyisocyanate derivative include dimer, trimer (isocyanurate ring-containing polyisocyanate), biuret, allophanate, carbon dioxide gas obtained by the reaction of the polyisocyanate monomer with 2,4,6. -Polyisocyanate having an oxadiazine trione ring, carbodiimide, uretdione, polymethylene polyphenyl polyisocyanate and the like.

  Furthermore, as a modified polyisocyanate, for example, the above polyisocyanate or a polyisocyanate derivative and a polyol or polyamine, the isocyanate group of the polyisocyanate is in excess of the hydroxyl group of the polyol or the amino group of the polyamine. Examples include polyol modified products and polyamine modified products obtained by reacting at such an equivalent ratio. These polyisocyanate (C) may be used independently and may use 2 or more types together.

  Typical commercial products of such polyisocyanate (C) include TSA-100, TSR-100, TSS-100, TSE-100 (manufactured by Asahi Kasei Chemicals Corporation), Takenate D-170N, 177N (Mitsui Chemicals, Inc.) Company-made), Vernock DN-990, DN-992 (manufactured by DIC Corporation), coronate HX, HXR, HXLV (manufactured by Nippon Polyurethane Co., Ltd.) and the like.

<Silane coupling agent (D)>
The silane coupling agent (D) is not particularly limited as long as it has two different functional groups in the same molecule.
The silane coupling agent (D) has an alkoxysilyl group as one functional group of two different functional groups. The silane coupling agent (D) has a trimethoxysilyl group or a triethoxysilyl group as one functional group of two different functional groups. Thus, since the silane coupling agent (D) has a trisubstituted alkoxysilyl group such as a trimethoxysilyl group or a triethoxysilyl group, the adhesion between the metal substrate and the coating film to be formed is improved. It tends to be improved and the rust prevention property of the formed coating film tends to be improved.

  Examples of the other functional group of the two different functional groups of the silane coupling agent (D) include an isocyanate group, an isocyanurate group, an epoxy group, an amino group, an acryloyl group, a methacryloyl group, a vinyl group, and a mercapto group. be able to. It is preferable that a silane coupling agent (D) has an isocyanate group, an isocyanurate group, or an epoxy group as the other functional group of two different types of functional groups. When the silane coupling agent (D) has these functional groups, the adhesion between the metal substrate and the formed coating film is improved, and the rust prevention property of the formed coating film tends to be improved. That is, when the silane coupling agent (D) has an isocyanate group or an isocyanurate group, these functional groups are bonded to the hydroxyl group of the alkyd part of the modified copolymer resin (A). Moreover, when a silane coupling agent (D) has an epoxy group, an epoxy group couple | bonds with the carboxyl group of an acrylic part by acid epoxy reaction. Thus, since the silane coupling agent (D) has an isocyanate group, an isocyanurate group or an epoxy group, the silane coupling agent (D) is easily taken into the formed coating film, resulting in a metal group. The adhesion between the material and the coating film to be formed will be improved.

  Specific examples of the silane coupling agent (D) include isocyanate groups such as γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, and γ-isocyanatopropylmethyldimethoxysilane. Silanes: γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- Epoxy group-containing silanes such as (3,4-epoxycyclohexyl) ethyltriethoxysilane; γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysila , Γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2 -Aminoethyl) aminopropyltriethoxysilane, gamma- (2-aminoethyl) aminopropylmethyldiethoxysilane, gamma- (2-aminoethyl) aminopropyltriisopropoxysilane, gamma-ureidopropyltrimethoxysilane, N- Amino group-containing silanes such as phenyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane; γ-mercaptopropyltrimethoxysilane, γ-mercaptop Mercapto group-containing silanes such as propyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane; β-carboxyethyltriethoxysilane, β-carboxyethylphenylbis (2-methoxyethoxy) Carboxysilanes such as silane, N-β- (carboxymethyl) aminoethyl-γ-aminopropyltrimethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-acryloyloxy Vinyl-type unsaturated group-containing silanes such as propylmethyltriethoxysilane; Halogen-containing silanes such as γ-chloropropyltrimethoxysilane; Isocyanurates such as tris (trimethoxysilyl) isocyanurate Orchids; and bis (3-triethoxysilylpropyl) polysulfane such as tetrasulfane like.

  Typical commercial products of such silane coupling agents (D) include KBM-403 (3-glycidoxypropyltrimethoxysilane), KBE-403 (3-glycidoxypropyltriethoxysilane), KBM. -9659 (tris- (trimethoxysilylpropyl) isocyanurate), KBE-9007 (3-isocyanatopropyltriethoxysilane), KBE-402 (3-glycidoxypropylmethyldimethoxysilane), KBM-303 (2- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane), KBE-903 (3-aminopropyltriethoxysilane), and the like (all manufactured by Shin-Etsu Chemical Co., Ltd.).

  The content of the polyisocyanate (C) and the silane coupling agent (D) in the reinforcing agent is preferably 10 to 90% by mass, and more preferably 40 to 70% by mass.

  When a reinforcing agent is used in addition to the coating composition, the equivalent ratio of the isocyanate group derived from the polyisocyanate (C) in the reinforcing agent to the hydroxyl group derived from the modified copolymer resin (A) (NCO equivalent / OH Equivalent) is preferably 0.5 to 1.5. When the value of the equivalent ratio (NCO equivalent / OH equivalent) is less than 0.5, the effect is not exhibited, and when it is more than 1.5, the formed coating film tends to be sticky.

  Furthermore, it is preferable that content of a silane coupling agent (D) with respect to the total solid in a coating composition is 0.1-10 mass%. When the content of the silane coupling agent (D) in the total solid content is less than 0.1% by mass, the rust preventive property of the formed coating film tends not to be exhibited. The storage stability of the coating composition tends to decrease, and the handleability of the coating composition tends to decrease. The content of the silane coupling agent (D) with respect to the total solid content in the coating composition is more preferably 0.5 to 3.0% by mass.

  Moreover, it is preferable that the total solid content density | concentration in the coating composition of this embodiment is 30-70 mass%. When the total solid content concentration of the coating composition is outside the above range, handling of the coating composition tends to be difficult.

  In addition to the above-described components, the coating composition according to the present invention may contain pigments and other additives (leveling agents, sagging prevention agents, etc.) within a range that does not impair the effects of the present invention. Good.

  The coating composition according to this embodiment includes a modified copolymer resin (A) and a modified fluorinated ethylene composition (B), and also a polyisocyanate (C) and a silane coupling agent (D). Can be used as a coating material containing only the modified copolymer resin (A) and the modified fluorinated ethylene composition (B). Moreover, in addition to these components, quick-drying property can be provided to a coating material by adding the reinforcing agent which consists of a polyisocyanate (C) and a silane coupling agent (D) to a coating composition.

  The coating composition in the present embodiment comprises a reinforcing agent composed of a modified copolymer resin (A), a modified fluorinated ethylene composition (B), and optionally a polyisocyanate (C) and a silane coupling agent (D). It is prepared by mixing with a solvent. As the solvent, a weak solvent is preferably used. By using a weak solvent as a solvent, even if a coating film is already formed on the surface of the metal roof, it is possible to repeat the coating without attacking the existing coating film. Therefore, the coating composition according to the present embodiment can be preferably used for recoating a coating film when renovating a metal roof.

  The weak solvent is an aliphatic hydrocarbon solvent that has a high flash point, a high boiling point, a low odor, and a low toxicity, as typified by terpenes and mineral spirits. Examples of the mixed solvent include mineral spirit, white spirit, mineral turpentine, isoparaffin, solvent kerosene, aromatic naphtha, VM & P naphtha, and solvent naphtha. Examples of commercially available products include Solvesso 100, Solvesso 150, Solvesso 200 manufactured by Esso Petroleum, Swazol 310, Swazol 1000, and Swazol 1500 manufactured by Cosmo Oil. In addition, as the single component solvent, aliphatic hydrocarbons such as n-butane, n-hexane, n-heptane, n-octane, isononane, n-decane, n-dodecane, cyclopentane, cyclohexane and cyclobutane are used. It is done.

  As a method for preparing the coating composition according to the present embodiment, a special method is not required, and a method usually used by those skilled in the art can be used. For example, each component is added to a disper, ball mill, S.I. G. The method of preparing by disperse | distributing in a solvent with dispersers, such as a mill and a roll mill, can be mentioned.

<Coating film>
The coating film formed from the coating composition according to the present embodiment has a DuPont-type impact shape jig (diameter = 12.7 mm, weight weight 300 g) with an ice film having a thickness of 1 mm formed on the coating film. ), The initial impact value is 200 mm or more. The impact test using the DuPont-type impact shape jig is performed according to JIS K 5600-5-3. The initial impact value of 200 mm or more means that the coating film after the test was cracked or peeled off when the above test for dropping the above-mentioned DuPont-type impact shape jig from an arbitrary height was performed. It indicates that the height of the jig that cannot be used is 200 mm or more.
When the coating film formed with the coating composition according to the present embodiment has an initial impact value of 200 mm or more in the impact test, it can be evaluated that the formed coating film has a performance that is difficult to peel off with ice and snow. .

[Coating film forming method]
The coating film forming method according to the present embodiment includes a painting process and a curing process.

In the coating process, the coating composition is applied to the surface of the metal substrate using a brush, a roller, a spray, or the like.
In the coating process, it is preferable that the coating film to be formed is coated so that the film thickness (film thickness after curing) is 10 to 100 μm. When it coats so that the film thickness after hardening may be less than 10 micrometers, the protective effect of a metal base material will become low. On the other hand, when the coating composition is applied so that the film thickness after curing exceeds 100 μm, the amount of the coating composition used for forming the coating film tends to increase, and the cost tends to increase. There is a risk of poor flow and drying.

  The method for curing the mixed coating composition in the curing step is not particularly limited, but usually a coating film is formed by leaving the metal substrate under natural conditions. When a reinforcing agent composed of polyisocyanate (C) and silane coupling agent (D) is added to the coating composition, the drying time can be shortened.

According to the coating composition according to the present embodiment described above, the following effects are exhibited.
In the present embodiment, in the coating composition for metal roof including the modified copolymer resin (A) and the modified fluorinated ethylene composition (B), the modified copolymer resin (A) is oxidatively polymerizable. And a modified copolymer resin having a structure derived from a (meth) acrylic copolymer, and the modified fluorinated ethylene composition (B) has a weight average molecular weight of 10,000 or more and less than 100,000. The modified fluorinated ethylene composition (B) has a solid content of 1 to 20 parts by mass with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A).
Thereby, not only can a high-strength coating film be formed by the formation reaction of the coating film with the modified copolymer resin (A) itself, but the modified fluoroethylene composition (B) is contained in the coating composition, Even when ice and snow adhere to the surface of the coating film, it is possible to form a coating film that is difficult to peel off along with the snow and ice.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

  As the coating compositions according to Examples and Comparative Examples, modified copolymer resins (A) and commercially available products respectively obtained by Synthesis Examples (1) to (3) shown below were used.

[Synthesis of oxidation-curing alkyd resin]
By conventional methods, soybean oil, glycerin, lithium hydroxide, and phthalic anhydride were synthesized in Solvesso 100 to obtain an oxidatively curable alkyd resin (V). The obtained oxidation curable alkyd resin (V) had a number average molecular weight of 2,500, an acid value of 44, an oil length of 62%, and a solid content of 60%.

[Synthesis Example of Modified Copolymer Resin (A-1)]
By a conventional method, 2-hydroxyethyl methacrylate, 2-ethylhexyl acrylate, and glycidyl methacrylate were synthesized in Solvesso 100 to obtain a (meth) acrylic resin copolymer (W). The (meth) acrylic resin copolymer (W) had a number average molecular weight of 8,200, a hydroxyl value of 20, and a solid content of 54.5%.
Next, a modified copolymer obtained by reacting the obtained oxidation curable alkyd resin (V), (meth) acrylic resin copolymer (W) and Z-6018 (Toray Dow Corning) as a silicone resin in a reaction vessel. Resin (A-1) was obtained. The obtained modified copolymer resin (A-1) had an iodine value of 10, a hydroxyl value of 13, a solid content of 62%, and a silicone content derived from a silicone resin of 1%.

[Synthesis Example of Modified Copolymer Resin (A-2)]
By a conventional method, 2-hydroxyethyl methacrylate, 2-ethylhexyl acrylate, and glycidyl methacrylate were synthesized in Solvesso 100 to obtain a (meth) acrylic resin copolymer (W). The (meth) acrylic resin copolymer (W) had a number average molecular weight of 8,200, a hydroxyl value of 20, and a solid content of 54.5%.
Subsequently, the modified curable alkyd resin (V) and the (meth) acrylic resin copolymer (W) obtained above were reacted in a reaction vessel to obtain a modified copolymer resin (A-2). The obtained modified copolymer resin (A-2) had an iodine value of 10, a hydroxylation of 12, and a solid content of 62%.

[Synthesis Example of Modified Copolymer Resin (A-3)]
After synthesizing the aforementioned oxidatively curable alkyd resin (V), Z-6018 was charged into a reaction vessel, and 2-hydroxyethyl methacrylate, 2-ethylhexyl acrylate, and glycidyl methacrylate were added to the reaction vessel by a conventional method to modify A copolymer resin (A-2) was obtained. The obtained modified copolymer resin (A-3) had an iodine value of 9, a hydroxyl value of 12, a solid content of 61%, and a silicone content derived from a silicone resin of 1%.

[Synthesis Example of Modified Copolymer Resin (A-4)]
The reaction vessel was reacted with soybean oil fatty acid, glycidyl methacrylate, hydroquinone, and tetraethylammonium bromide in Solvesso 100 to carry out an addition reaction between the epoxy group of glycidyl methacrylate and the carboxyl group of soybean oil fatty acid. Subsequently, 2-hydroxyethyl methacrylate, 2-ethylhexyl acrylate, glycidyl methacrylate, and Z-6018 were added to the reaction vessel to obtain a modified copolymer resin (A-4) by a conventional method. The obtained modified copolymer resin (A-4) had an iodine value of 14, a hydroxyl value of 12, a solid content of 62%, and the content of silicone derived from the silicone resin was 1%.

[Synthesis Example of Modified Copolymer Resin (A-5) 2-hydroxyethyl methacrylate, 2-ethylhexyl acrylate, glycidyl methacrylate, soybean oil fatty acid, Z-6018 were reacted in a reaction vessel by a conventional method, and modified A copolymer resin (A-5) was obtained. The obtained modified copolymer resin (A-5) had an iodine value of 12, a hydroxyl value of 13, a solid content of 63%, and a silicone content derived from a silicone resin of 1%.

Copolymer resin (A-6): DIC 1334-EL (solid content 50%, alkyd resin, manufactured by DIC Corporation)
Copolymer resin (A-7): DIC WAN-347 (solid content 50%, silicone resin, manufactured by DIC Corporation)

In addition, the following were used as the modified fluorinated ethylene composition (B).
Weak solvent soluble modified ethylene fluoride composition b-1: Lumiflon LF-800 (solid content 60%, molecular weight 25,000, manufactured by Asahi Glass Co., Ltd.)
Solvent-soluble modified ethylene fluoride composition b-2: Lumiflon LF-400 (solid content 50%, molecular weight 20,000, manufactured by Asahi Glass Co., Ltd.)
Solvent-soluble modified ethylene fluoride composition b-3: Lumiflon LF-200 (solid content 60%, molecular weight 50,000, manufactured by Asahi Glass Co., Ltd.)
Solvent-soluble modified ethylene fluoride composition b-4: Lumiflon LF-100 (solid content 50%, molecular weight 100,000, manufactured by Asahi Glass Co., Ltd.)
Solvent-soluble modified fluorinated ethylene composition b-5: Megafac F-444 (100% solids, molecular weight 4,800, manufactured by DIC Corporation)

Moreover, the following were used as isocyanate (C).
Weak solvent soluble isocyanate c-1: Duranate TSA-100 (solid content 100%, HDI nurate type, NCO%: 20.6%, manufactured by Asahi Kasei Chemicals Corporation)

Moreover, the following were used as a silane coupling agent (D).
3-glycidoxypropyltriethoxysilane: KBE-403 (manufactured by Shin-Etsu Chemical Co., Ltd.)

[Preparation of mixed coating composition]
[Examples 1 to 12 and Comparative Examples 1 to 5]
Each component was mixed so as to have a solid content (unit: part by mass) shown in Table 1, and a coating composition obtained by sufficiently stirring was obtained.

[Preparation of test plate for evaluation]
As a base material for the test plate for evaluation, a color tone (150 × 70 × 0.35 mm) was used. First, the coating composition was applied on the surface of the color totone using a brush so that the coating amount was 100 to 120 g / m ² . The coating composition was obtained by mixing so that each component of said Example or a comparative example might become solid content mass ratio (unit: mass part) as shown in Table 1.
Subsequently, the colored tones coated with the coating composition were left to dry at room temperature for 7 days to obtain test plates for evaluation of Examples and Comparative Examples.

<Shock test at 0 ° C>
The test plate for evaluation obtained using the paint compositions of Examples and Comparative Examples is enclosed with water-resistant tape, and after installing in a -20 ° C freezer, water is filled so that the water surface becomes 1 mm thick. did. After allowing to stand overnight and forming an ice film with a thickness of 1 mm, the test piece was immediately moved to a room at 5 ° C. and a DuPont-type impact shape jig (diameter = 12.7 mm, weight weight 300 g) was used. An impact test was performed. The impact test was conducted in accordance with JIS K 5600-5-3, and the coating film surface after the impact test was evaluated according to the following criteria, with “A” being passed and “B” being rejected. The results are shown in Table 1.
A: Cracking and peeling due to impact are not possible.
B: Cracking / peeling due to impact is possible.

<Ice pull-out test>
The test plate for evaluation obtained by using the coating compositions of Examples and Comparative Examples was immersed in a container filled with water so that a part of the test plate was exposed vertically and −20. It was completely frozen by storing for 1 day (24 hours) in a freezer set to ° C.
The container containing the above-mentioned frozen test plate is allowed to stand at room temperature (23 ° C.) for 5 minutes, the exposed upper part is sandwiched with a jig, and is pulled out from the container by applying a vertical force manually. The film surface was evaluated according to the following criteria. “A” was accepted and “B” was rejected. The results are shown in Table 1.
A: The coating film does not peel off.
B: The coating film peels off.

  From the comparison between Examples 1 to 12 and Comparative Examples 1 and 2, the coating compositions of Examples 1 to 12 can form a coating film that is more difficult to peel off with snow and ice than the coating composition of Comparative Example 1. I understood. From this result, it is possible to form a high-strength coating film by including the modified copolymer (A) having a structure derived from a (meth) acrylic copolymer having an oxidatively polymerizable group. At the same time, it became clear that it was possible to form a coating film that was difficult to peel off.

  From a comparison between Example 1 and Comparative Example 3, it was found that the coating composition of Example 1 can form a coating film that is more difficult to peel off with snow and snow than the coating composition of Comparative Example 3. From this result, since the solid content of the modified fluorinated ethylene composition (B) is 1 part by mass or more with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A), it adhered to the surface. It was revealed that a coating film with low adhesion to ice and snow can be formed, and a coating film that is difficult to peel off with ice and snow can be formed.

  From a comparison between Example 5 and Comparative Example 4, the coating composition of Example 5 had a higher impact at 0 ° C. than the coating composition of Comparative Example 4, and formed a coating film that was difficult to peel off with snow and ice. I understood that I could do it. From this result, the impact resistance is improved because the solid content of the modified fluorinated ethylene composition (B) is 20 parts by mass or less with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A). It was found that a good coating film can be formed and a coating film that is difficult to peel off with ice and snow can be formed.

  From a comparison between Example 7 and Comparative Example 6, it was found that the coating composition of Example 7 can form a coating film that is more difficult to peel off with snow and snow than the coating composition of Comparative Example 6. From this result, it is possible to form a high-strength coating film by using a modified ethylene fluoride composition (B) having a weight average molecular weight of 10,000 or more for the coating composition, and to form a coating film that is difficult to peel off with snow and ice. Became clear.

  From a comparison between Example 8 and Comparative Example 5, it was found that the coating composition of Example 8 had higher impact at 0 ° C. than the coating composition of Comparative Example 5. From this result, it is possible to form a coating film having good impact resistance by using the modified fluorinated ethylene composition (B) having a weight average molecular weight of less than 100,000 for the coating composition, and to form a coating film that is difficult to peel off with snow and ice. It became clear that it could be formed.

Claims (7)

A coating composition for a metal roof,
A modified copolymer resin (A) and a modified fluorinated ethylene composition (B),
The modified copolymer resin (A) is a modified copolymer resin having an oxidation polymerizable group and having a structure derived from a (meth) acrylic copolymer,
The modified fluorinated ethylene composition (B) has a weight average molecular weight of 10,000 or more and less than 100,000,
The coating composition whose solid content of the said modified | denatured fluoroethylene composition (B) is 1-20 mass parts with respect to 100 mass parts of total solid content of the said modified copolymer resin (A). The modified copolymer resin (A) is:
A modified copolymer resin (A-1) obtained by a reaction between a (meth) acrylic resin and an alkyd resin;
A copolymer resin (A-2) obtained by a polymerization reaction of a reactive vinyl group and an alkyd resin having an oxidative polymerizable group;
A copolymer resin (A-3) obtained by a polymerization reaction between a reactive vinyl group having an oxidative polymerizable group and another reactive vinyl group;
It contains at least one selected from the group consisting of a copolymer of a reactive vinyl group having a glycidyl group and a modified copolymer resin (A-4) obtained by a polymerization reaction of an unsaturated fatty acid capable of oxidative polymerization. The coating composition according to claim 1.   The coating composition according to claim 1 or 2, wherein the modified copolymer resin (A) is further modified with silicone.   The coating composition according to any one of claims 1 to 3, wherein the modified fluorinated ethylene composition (B) is subjected to weak solvent solubilization modification.   The solid content of the modified fluorinated ethylene composition (B) is 2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the modified copolymer resin (A). The coating composition as described.   The coating composition according to any one of claims 1 to 5, further comprising a polyisocyanate (C) and a silane coupling agent (D) having two different functional groups in the same molecule. A coating film formed from the coating composition according to any one of claims 1 to 6,
In accordance with JIS K 5600-5-3 using a DuPont-type impact shape jig (diameter = 12.7 mm, weight weight 300 g) with an ice film having a thickness of 1 mm formed on the coating film. A coating film having an initial impact value of 200 mm or more in an impact test.