Curable composition for spray coating

Abstract

This curable composition for spray coating contains 100 parts by weight of a polyoxyalkylene-based polymer (A) that has a reactive silicon group, 10-50 parts by weight of a hydrocarbon-based diluent (B), 30-90 parts by weight of a plasticizer (C) that is a cyclic hydrocarbon group-containing dicarboxylic acid ester, and 0.6-7 parts by weight of a polyamide-based rheology modifier (D). A cured film is produced by spray-coating the surface of a base material with the curable composition and subsequently curing the curable composition.

Description

Curable composition for spray coating

[0001] The present invention relates to a curable composition for spray coating containing a polyoxyalkylene polymer having a reactive silicon group, and to a cured film using the composition or a method for producing the same.

[0002] Organic polymers containing silicon groups that have hydroxyl groups or hydrolyzable groups on silicon atoms and that can form siloxane bonds through hydrolysis and condensation reactions (hereinafter also referred to as "reactive silicon groups") react with moisture, etc., even at room temperature. It is known that such organic polymers can be crosslinked by the siloxane condensation reaction of the reactive silicon groups to yield rubber-like cured products.

[0003] Among these organic polymers, polyoxyalkylene polymers having reactive silicon groups are widely used in applications such as sealants, adhesives, and paints because of their well-balanced performance, including mechanical properties, weather resistance, and dynamic durability of the cured product.

[0004] Spray coating has been investigated as one method for efficiently applying a curable composition containing a polyoxyalkylene polymer having a reactive silicon group to a substrate.

[0005] Patent Document 1 discloses a curable composition for spray coating that contains a polymer having a reactive silicon group, a plasticizer, a filler having a specific particle size, and a catalyst. It is disclosed that this composition achieves excellent spray coating properties, deep curing properties, and tile retention (adhesion). Applications of the composition include tile adhesives and sealants.

[0006] Patent Document 2 discloses a sprayable composition containing an α,ω-telechelic silyl-terminated polymer such as a silylated polyether and a glycol diester as a plasticizer, and discloses that a thixotropic agent can be blended into the composition.

[0007] JP 2023-7423 A JP 2019-530769 A

[0008] One application under consideration for a curable composition containing a reactive silicon group-containing polyoxyalkylene polymer is to spray the composition onto the wall surface of a building or the like, and then cure the composition to form a waterproof film.

[0009] In such applications, it is desirable to apply the composition using an airless spray gun so that spray coating can be performed on a large-area substrate in a short time. In this case, the curable composition is required to have properties that make it easy to apply the composition by spray coating (spray coatability) using such a coating device. In addition, the coating film is required to be less likely to drip after spray coating until the composition is cured.

[0010] Generally, reducing the viscosity of a composition improves spray coatability, but conversely, tends to decrease sagging resistance. Therefore, it is not easy to achieve both spray coatability and sagging resistance.

[0011] It is generally known that a rheology control agent is added as a component that imparts sagging resistance to a curable composition.

[0012] Patent Document 1 does not describe the use of the composition for forming a waterproof film, and no rheology modifier is used. Therefore, it is difficult to achieve sagging resistance. Furthermore, in the examples, a spray gun using air pressure is used as the coating device, and spray coating of large-area substrates is not considered, nor is a formulation for achieving such spray coating disclosed.

[0013] Patent Document 2 describes the incorporation of a rheology modifier, but also describes that spray coating is carried out at high pressure. Through investigations by the present inventors, it was found that the formulation using the plasticizer (glycol diester) disclosed in the document does not provide sufficient spray coating properties and that improvement is necessary.

[0014] The present inventors have investigated the incorporation of a rheology modifier to impart sagging resistance and a low-volatility diluent as a component to reduce the viscosity of the composition, but have found that the incorporation of such a diluent can cause liquid components to bleed out from the surface of the cured film.

[0015] In view of the above-mentioned current situation, an object of the present invention is to provide a curable composition for spray coating that contains a reactive silicon group-containing polyoxyalkylene polymer, which has both spray coatability and resistance to sagging after coating, and can also suppress bleed-out after curing.

[0016]

[0005] As a result of intensive research aimed at solving the above problems, the present inventors have found that by blending a specific rheology modifier, a specific diluent, and a specific plasticizer with a polyoxyalkylene polymer having a reactive silicon group, it is possible to achieve both spray coatability and resistance to sagging after coating. Furthermore, by limiting the amounts of the specific diluent and the specific plasticizer used, it has been found that bleeding out after curing can also be avoided, leading to the completion of the present invention.

[0017] Specifically, the present invention relates to a curable composition for spray coating, comprising 100 parts by weight of a polyoxyalkylene polymer (A) having a reactive silicon group, 10 to 50 parts by weight of a hydrocarbon diluent (B), 30 to 90 parts by weight of a plasticizer (C) that is a cyclic hydrocarbon group-containing dicarboxylic acid ester, and 0.6 to 7 parts by weight of a polyamide rheology modifier (D). The present invention also relates to a cured film obtained by spray-coating and curing the curable composition. Furthermore, the present invention also relates to a method for producing a cured film, comprising spray-coating the curable composition onto a substrate surface and then curing the composition.

[0018] According to the present invention, it is possible to provide a curable composition for spray coating that contains a reactive silicon group-containing polyoxyalkylene polymer, which has both spray coatability and resistance to sagging after coating, and is also capable of suppressing bleed-out after curing.

[0019] Embodiments of the present invention are described below. <<Polyoxyalkylene Polymer (A)>> The curable composition for spray coating according to the present disclosure contains a polyoxyalkylene polymer (A) having a reactive silicon group as a curable resin.

[0020] <Reactive Silicon Group> The reactive silicon group contained in the polyoxyalkylene polymer (A) can be represented by the following general formula (1): —Si(R １ ) ３－ａ X １ ａ (1)

[0021] In general formula (1), R １ R each independently represents a monovalent hydrocarbon group having 1 to 20 carbon atoms. １ The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, more preferably 1 to 6, and particularly preferably 1 to 4. The hydrocarbon group may be an unsubstituted hydrocarbon group or a hydrocarbon group having a substituent.

[0022] R １ The hydrocarbon group may have a hetero-containing group as a substituent. The hetero-containing group is a group containing a hetero atom. Here, atoms other than carbon atoms and hydrogen atoms are defined as hetero atoms.

[0023] Suitable examples of heteroatoms include N, O, S, P, Si, and halogen atoms. In the hetero-containing group, the total number of carbon atoms and heteroatoms is preferably 1 to 10, more preferably 1 to 6, and still more preferably 1 to 4.

[0024] Suitable examples of hetero-containing groups include a hydroxyl group; a mercapto group; halogen atoms such as Cl, Br, I, and F; a nitro group; a cyano group; alkoxy groups such as a methoxy group, an ethoxy group, an n-propyloxy group, and an isopropyloxy group; alkylthio groups such as a methylthio group, an ethylthio group, an n-propylthio group, and an isopropylthio group; acyl groups such as an acetyl group, a propionyl group, and a butanoyl group; acyloxy groups such as an acetyloxy group, a propionyloxy group, and a butanoyloxy group; substituted or unsubstituted amino groups such as an amino group, a methylamino group, an ethylamino group, a dimethylamino group, and a diethylamino group; substituted or unsubstituted aminocarbonyl groups such as an aminocarbonyl group, a methylaminocarbonyl group, an ethylaminocarbonyl group, a dimethylaminocarbonyl group, and a diethylaminocarbonyl group; and a cyano group.

[0025] R １ is a hydrocarbon group having a hetero-containing group, R １ The total number of carbon atoms and hetero atoms in is preferably 2 to 30, more preferably 2 to 18, even more preferably 2 to 10, and particularly preferably 2 to 6.

[0026] R １ Specific examples of the hydrocarbon group having 1 to 20 carbon atoms as the alkyl group include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethyl-n-hexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-icosyl group; and a vinyl group. alkenyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups; aryl groups such as phenyl, naphthalen-1-yl, naphthalen-2-yl, o-phenylphenyl, m-phenylphenyl, and p-phenylphenyl groups; and aralkyl groups such as benzyl, phenethyl, naphthalen-1-ylmethyl, and naphthalen-2-ylmethyl groups.

[0027] These hydrocarbon groups substituted with the hetero-containing groups described above are also included in R １ It is preferable as.

[0028] R １ Suitable examples of R include alkyl groups such as methyl and ethyl groups; alkyl groups having a hetero-containing group such as chloromethyl and methoxymethyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl groups; and aralkyl groups such as benzyl groups. １ As the alkyl group, a methyl group, a methoxymethyl group, and a chloromethyl group are preferred, a methyl group and a methoxymethyl group are more preferred, and a methyl group is even more preferred.

[0029] X １ each independently represents a hydroxyl group or a hydrolyzable group. １ Specific examples of the reactive silicon group include a hydroxyl group, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, an alkoxy group is more preferred because it is mildly hydrolyzable and easy to handle. Generally, the fewer the carbon atoms in an alkoxy group, the higher the reactivity. That is, the reactivity decreases in the order of a methoxy group, an ethoxy group, and a propoxy group. By utilizing this property, the specific structure of the reactive silicon group can be appropriately determined depending on the production method and application of the polyoxyalkylene polymer (A).

[0030] a is 1, 2, or 3. Since the strength of the cured product is improved, a is preferably 2 or 3. Since it is easier to achieve both strength and elongation of the cured product, a is more preferably 2.

[0031] Specific examples of reactive silicon groups contained in the polyoxyalkylene polymer (A) include, but are not limited to, trimethoxysilyl, triethoxysilyl, tris(2-propenyloxy)silyl, triacetoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethoxyethylsilyl, (chloromethyl)dimethoxysilyl, (chloromethyl)diethoxysilyl, (methoxymethyl)dimethoxysilyl, (methoxymethyl)diethoxysilyl, (N,N-diethylaminomethyl)dimethoxysilyl, and (N,N-diethylaminomethyl)diethoxysilyl groups. Among these, dimethoxymethylsilyl, trimethoxysilyl, triethoxysilyl, and (methoxymethyl)dimethoxysilyl groups are preferred because they give cured products with good mechanical properties. From the viewpoint of activity, trimethoxysilyl group, (chloromethyl)dimethoxysilyl group, and (methoxymethyl)dimethoxysilyl group are more preferred, and trimethoxysilyl group is particularly preferred because it improves curability.

[0032] The number of reactive silicon groups in one molecule of the polyoxyalkylene polymer (A) is preferably 1 to 7 on average, more preferably 1.1 to 3.4, and particularly preferably 1.2 to 2.6, from the viewpoint of the balance between flexibility and recovery.

[0033] In order to obtain a good rubber-like cured product, the reactive silicon groups of the polyoxyalkylene polymer (A) are preferably present at the terminals of the main chain. In order to show good curability and easily exhibit rubber elastic behavior, the number of reactive silicon groups per terminal of the polymer (A) is preferably 0.5 or more on average, more preferably 0.6 or more, even more preferably 0.7 or more, even more preferably 0.8 or more, and particularly preferably 0.85 or more.

[0034] The main chain structure of the polyoxyalkylene polymer (A) may be linear or branched. When a linear polyoxyalkylene polymer (A) is used, the polymer has good conformability even when spray-coated onto a substrate that is prone to thermal expansion and contraction to form a cured film.

[0035] The main chain of the polyoxyalkylene polymer (A) is -R １３ -O- (wherein, R １３ is a linear or branched alkylene group having 1 to 14 carbon atoms), and R １３ is more preferably a linear or branched alkylene group having 2 to 4 carbon atoms. １３ Specific examples of the repeating unit represented by —O— include —CH ２ O-, -CH ２ CH ２ O-, -CH ２ CH (CH ３ ) O—, —CH ２ C(CH ３ ) (CH ３ ) O—, —CH ２ CH ２ CH ２ CH ２ O-, etc., but -CH ２ CH ２ O-, -CH ２ CH (CH ３)O— is preferred, and —CH ２ CH (CH ３ ) O- is more preferred.

[0036] In particular, polyoxypropylene polymers having oxypropylene repeating units in an amount of preferably 50% by weight or more, more preferably 80% by weight or more of the polymer main chain structure are preferred because they are amorphous and have a relatively low viscosity.

[0037] The polyoxyalkylene polymer (A) may be a polyoxyalkylene polymer containing other bonds such as a urethane bond, a urea bond, an ester bond, an amide bond, etc. in its main chain structure. However, from the viewpoint of obtaining a curable composition excellent in storage stability and workability, the polyoxyalkylene polymer (A) is preferably a polyoxyalkylene polymer that does not contain a urethane bond, a urea bond, an ester bond, or an amide bond in its main chain structure.

[0038] The number average molecular weight of the polyoxyalkylene polymer (A) is not particularly limited, but is preferably 5,000 to 100,000, more preferably 10,000 to 50,000, particularly preferably 12,000 to 40,000, and most preferably 13,000 to 30,000, as calculated in terms of polystyrene by GPC measurement. When the number average molecular weight is within the above range, the amount of reactive silicon groups introduced is appropriate, making it easy to obtain a polyoxyalkylene polymer (A) with high strength while keeping production costs within an appropriate range.

[0039] The molecular weight distribution (Mw / Mn) of the polyoxyalkylene polymer (A) is not particularly limited, but is preferably narrow. Specifically, it is preferably 1.6 or less, more preferably 1.4 or less, even more preferably 1.3 or less, and particularly preferably 1.2 or less. A molecular weight distribution within the above range is preferable from the viewpoints of ease of handling such as workability and adhesiveness. The molecular weight distribution of the polyoxyalkylene polymer (A) can be determined from the number average molecular weight and weight average molecular weight obtained by GPC measurement.

[0040] <Method for producing reactive silicon group-containing polyoxyalkylene polymer (A)> Next, a method for producing the reactive silicon group-containing polyoxyalkylene polymer (A) will be described. The reactive silicon group-containing polyoxyalkylene polymer (A) can be produced by introducing a reactive silicon group into a precursor polymer to which a reactive silicon group can be introduced. Specifically, the reactive silicon group-containing polyoxyalkylene polymer (A) can be produced by introducing an olefin group into a polyoxyalkylene polymer (d1) having a terminal hydroxyl group by utilizing the reactivity of the hydroxyl group to obtain a precursor polymer having an olefin group, and then reacting the precursor polymer with a reactive silicon group-containing compound reactive with the olefin group to introduce the reactive silicon group.

[0041] (Polymerization) The polymer backbone of the polyoxyalkylene polymer can be formed by polymerizing an epoxy compound with an initiator having a hydroxyl group by a conventionally known method, thereby obtaining a polyoxyalkylene polymer (d1) having a hydroxyl group at its terminal. Although the specific polymerization method is not particularly limited, a polymerization method using a composite metal cyanide complex catalyst such as a zinc hexacyanocobaltate glyme complex is preferred because it can produce a hydroxyl-terminated polymer with a small molecular weight distribution (Mw / Mn).

[0042] The initiator having a hydroxyl group is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, glycerin, pentaerythritol, low-molecular-weight polyoxypropylene glycol, low-molecular-weight polyoxypropylene triol, butanol, allyl alcohol, methanol, ethanol, propanol, butanol, pentanol, hexanol, low-molecular-weight polyoxypropylene monoallyl ether, low-molecular-weight polyoxypropylene monoalkyl ether, etc. When a polymer having three or more main chain ends in one molecule is to be obtained, glycerin, pentaerythritol, low-molecular-weight polyoxypropylene triol, etc. having three or more hydroxyl groups can be used.

[0043] The epoxy compound is not particularly limited, but examples thereof include alkylene oxides such as ethylene oxide and propylene oxide, and glycidyl ethers such as methyl glycidyl ether and butyl glycidyl ether, with propylene oxide being preferred.

[0044] (Reaction with alkali metal salt) When introducing an olefin group into a polyoxyalkylene polymer (d1) having a terminal hydroxyl group, it is preferable to first react an alkali metal salt with the polyoxyalkylene polymer (d1) to convert the terminal hydroxyl group into an alkoxide terminal. Alternatively, a composite metal cyanide complex catalyst can be used instead of the alkali metal salt. In this manner, an alkoxide-terminated polyoxyalkylene polymer (d2) is formed.

[0045] The alkali metal salt is not particularly limited, but examples thereof include sodium hydroxide, sodium alkoxide, potassium hydroxide, potassium alkoxide, lithium hydroxide, lithium alkoxide, cesium hydroxide, and cesium alkoxide. From the viewpoint of ease of handling and solubility, sodium hydroxide, sodium methoxide, sodium ethoxide, sodium tert-butoxide, potassium hydroxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide are preferred, with sodium methoxide and sodium tert-butoxide being more preferred. From the viewpoint of availability, sodium methoxide is preferred. The alkali metal salt may be subjected to the reaction in a state dissolved in a solvent.

[0046] (Reaction with Electrophile (d3)) The alkoxide-terminated polyoxyalkylene polymer (d2) obtained as described above is reacted with an electrophile (d3) having an olefin group to convert the alkoxide terminal into a structure containing an olefin group, thereby forming a polyoxyalkylene polymer (d4) having an olefin group in the terminal structure.

[0047] The electrophilic agent (d3) having an olefin group is not particularly limited as long as it is a compound that can react with the alkoxide terminal of the polyoxyalkylene polymer (d2) and introduce an olefin group into the polyoxyalkylene polymer, and examples thereof include an organic halide (d3-1) having an olefin group and an epoxy compound (d3-2) having an olefin group.

[0048] The organic halide (d3-1) having an olefin group, which is one embodiment of the electrophilic agent (d3), reacts with the alkoxide terminal through a halogen substitution reaction to form an ether bond, thereby introducing a structure containing an olefin group as a terminal structure of the polyoxyalkylene polymer.

[0049] Specific examples of the organic halide (d3-1) having an olefin group include, but are not limited to, vinyl chloride, allyl chloride, methallyl chloride, vinyl bromide, allyl bromide, methallyl bromide, vinyl iodide, allyl iodide, and methallyl iodide. From the viewpoint of ease of handling, allyl chloride and methallyl chloride are preferred. Furthermore, methallyl chloride, methallyl bromide, and methallyl iodide are preferred because they improve the average ratio of the number of reactive silicon groups to the number of terminals of the polymer skeleton.

[0050] Furthermore, a halogenated hydrocarbon compound having a carbon-carbon triple bond can also be used as the organic halide (d3-1) having an olefin group. The halogenated hydrocarbon compound having a carbon-carbon triple bond is not particularly limited, and examples thereof include propargyl chloride, propargyl bromide, and propargyl iodide. Furthermore, a halogenated hydrocarbon compound having a carbon-carbon double bond may be used simultaneously with the halogenated hydrocarbon compound having a carbon-carbon triple bond.

[0051] An epoxy compound (d3-2) having an olefin group, which is another embodiment of the electrophile (d3), can react with the alkoxide terminal through a ring-opening addition reaction of the epoxy group to form an ether bond, thereby introducing a structure containing an olefin group and a hydroxyl group as a terminal structure of the polyoxyalkylene polymer. In the ring-opening addition reaction, one or more epoxy compounds (d3-2) can be added to one alkoxide terminal by adjusting the amount of epoxy compound (d3-2) used relative to the alkoxide terminal and the reaction conditions.

[0052] Specific examples of the epoxy compound (d3-2) having an olefin group are not particularly limited, but allyl glycidyl ether, methallyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, and butadiene monoxide are preferred in terms of reactivity, and allyl glycidyl ether is particularly preferred.

[0053] As described above, when the alkoxide-terminated polyoxyalkylene polymer (d2) is reacted with the epoxy compound (d3-2) having an olefin group, a new alkoxide is generated by ring-opening of the epoxy group. Therefore, after the reaction with the epoxy compound (d3-2), the polymer can be reacted with the organic halide (d3-1) having an olefin group.

[0054] (Introduction of Reactive Silicon Groups) The polyoxyalkylene polymer (d4) having an olefin group in its terminal structure or the polyoxyalkylene polymer (d5) (precursor polymer) having a carbon-carbon triple bond in its terminal structure obtained as described above can be subjected to a hydrosilylation reaction with a hydrosilane compound (d6) having a reactive silicon group, thereby introducing a reactive silicon group into the polymer. This produces a reactive silicon group-containing polyoxyalkylene polymer (A). The hydrosilylation reaction has the advantages of being simple to carry out, easy to adjust the amount of reactive silicon group introduced, and stable physical properties of the resulting polymer.

[0055] Specific examples of the hydrosilane compound (d6) having a reactive silicon group include halosilanes such as trichlorosilane, dichloromethylsilane, chlorodimethylsilane, dichlorophenylsilane, (chloromethyl)dichlorosilane, (dichloromethyl)dichlorosilane, bis(chloromethyl)chlorosilane, (methoxymethyl)dichlorosilane, (dimethoxymethyl)dichlorosilane, and bis(methoxymethyl)chlorosilane; trimethoxysilane, triethoxysilane, dimethoxymethylsilane, diethoxymethylsilane, and the like. Tylsilane, dimethoxyphenylsilane, ethyldimethoxysilane, methoxydimethylsilane, ethoxydimethylsilane, (chloromethyl)methylmethoxysilane, (chloromethyl)dimethoxysilane, (chloromethyl)diethoxysilane, bis(chloromethyl)methoxysilane, (methoxymethyl)methylmethoxysilane, (methoxymethyl)dimethoxysilane, bis(methoxymethyl)methoxysilane, (methoxymethyl)diethoxysilane, (ethoxymethyl)diethoxysilane, (3,3,3-triphenylsilane) (chloromethyl)dimethoxysilane, (N,N-diethylaminomethyl)dimethoxysilane, (N,N-diethylaminomethyl)diethoxysilane, [(chloromethyl)dimethoxysilyloxy]dimethylsilane, [(chloromethyl)diethoxysilyloxy]dimethylsilane, [(methoxymethyl)dimethoxysilyloxy]dimethylsilane, [(methoxymethyl)diethoxysilyloxy]dimethylsilane, [(diethylaminomethyl)dimethoxysilyloxy]dimethylsilane, [(3,3,3-trichloromethyl)dimethoxysilyloxy]dimethylsilane alkoxysilanes such as [(fluoropropyl)dimethoxysilyloxy]dimethylsilane; acyloxysilanes such as diacetoxymethylsilane and diacetoxyphenylsilane; ketoximate silanes such as bis(dimethylketoximate)methylsilane and bis(cyclohexylketoximate)methylsilane; and isopropenyloxysilanes (deacetone type) such as triisopropenyloxysilane, (chloromethyl)diisopropenyloxysilane, and (methoxymethyl)diisopropenyloxysilane.

[0056] The hydrosilylation reaction is preferably carried out in the presence of a hydrosilylation catalyst to promote the reaction. Known hydrosilylation catalysts include metals such as cobalt, nickel, iridium, platinum, palladium, rhodium, and ruthenium, as well as complexes thereof, and these can be used. Specific examples of the hydrosilylation catalyst include platinum supported on a support such as alumina, silica, or carbon black; chloroplatinic acid; chloroplatinic acid complexes composed of chloroplatinic acid and alcohols, aldehydes, ketones, or the like; platinum-olefin complexes [e.g., Pt(CH ２ =CH ２ ) ２ (PPh ３ ), Pt(CH ２ =CH ２ ) ２ Cl ２ ]; platinum-vinylsiloxane complexes [e.g., Pt{(vinyl)Me ２ SiOSiMe ２ (vinyl)}, Pt{Me(vinyl)SiO} ４ platinum-phosphine complexes [e.g., Ph(PPh ３ ) ４ , Pt(PBu ３ ) ４ ]; platinum-phosphite complexes [e.g., Pt{P(OPh) ３} ４ ] etc.

[0057] It is known that when a platinum-based hydrosilylation catalyst is used, side reactions such as isomerization to 1-propenyl groups (internal olefins) and the generation of propenyl groups by hydrogenation occur, and these side reactions result in a decrease in the rate of reactive silicon group introduction into allyl groups (average number of reactive silicon groups per terminal).As a method for suppressing such side reactions and improving the rate of reactive silicon group introduction, for example, JP 2021-11456 A proposes the use of a ruthenium complex having a specific ligand.

[0058] A specific example is a method in which a ruthenium complex and a halogen-substituted olefin compound (such as 1,4-dibromobenzene, 1-bromo-3,5-difluorobenzene, 1-bromo-2,6-difluorobenzene, 1,4-diiodobenzene, and 1,3,5-tribromobenzene) are used in a hydrosilylation reaction. By using such a method, it is possible to obtain a polymer having an average number of reactive silicon groups per terminal of 0.85 or more. By using such a polymer in the present disclosure, it is possible to obtain a curable composition that provides a cured film exhibiting sufficient strength.

[0059] As another method for producing the reactive silicon group-containing polyoxyalkylene polymer (A), a method can also be applied in which a compound (d7) having a reactive silicon group and an isocyanate group in one molecule is allowed to react with a polyoxyalkylene polymer (d1) (precursor polymer) having a terminal hydroxyl group to form a urethane bond and introduce a reactive silicon group.

[0060] The compound (d7) having a reactive silicon group and an isocyanate group in one molecule is not particularly limited as long as it is a compound having both an isocyanate group capable of undergoing a urethane-forming reaction with a hydroxyl group in the polyoxyalkylene polymer (d1) and a reactive silicon group in one molecule. Specific examples include (3-isocyanatepropyl)trimethoxysilane, (3-isocyanatepropyl)dimethoxymethylsilane, (3-isocyanatepropyl)triethoxysilane, (3-isocyanatepropyl)diethoxymethylsilane, (isocyanatemethyl)trimethoxysilane, (isocyanatemethyl)triethoxysilane, (isocyanatemethyl)dimethoxymethylsilane, and (isocyanatemethyl)diethoxymethylsilane.

[0061] The urethanization reaction may be carried out without using a urethanization catalyst, or may be carried out in the presence of a urethanization catalyst for the purpose of improving the reaction rate or the reaction rate. Examples of such urethanization catalysts include conventionally known urethanization catalysts, such as those listed in "Polyurethanes: Chemistry and Technology," Part I, Table 30, Chapter 4, Saunders and Frisch, Interscience Publishers, New York, 1963. Specific examples include, but are not limited to, basic catalysts such as organotin compounds, bismuth compounds, and organic amines.

[0062] As yet another method for producing the reactive silicon group-containing polyoxyalkylene polymer (A), a method can also be applied in which an excess of a polyisocyanate compound (d8) is reacted with a polyoxyalkylene polymer (d1) having a terminal hydroxyl group to form a polymer (precursor polymer) having an isocyanate group at its terminal, and then the precursor polymer is reacted with a compound (d9) having a group reactive with an isocyanate group (e.g., an amino group) and a reactive silicon group.

[0063] Examples of the polyisocyanate compound (d8) include aromatic polyisocyanates such as toluene (tolylene) diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; and aliphatic polyisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate.

[0064] Examples of the compound (d9) having a group reactive with an isocyanate group and a reactive silicon group include γ-aminopropyltrimethoxysilane, γ-aminopropyldimethoxymethylsilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyldimethoxymethylsilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-(N-phenyl)aminopropyltrimethoxysilane, γ-(N-phenyl)aminopropyldi Examples thereof include amino group-containing silanes such as methoxymethylsilane, N-ethylaminoisobutyltrimethoxysilane, N-ethylaminoisobutyldimethoxymethylsilane, N-cyclohexylaminomethyltrimethoxysilane, and N-cyclohexylaminomethyldimethoxymethylsilane; hydroxy group-containing silanes such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyldimethoxymethylsilane; and mercapto group-containing silanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyldimethoxymethylsilane.

[0065] As yet another method for producing the reactive silicon group-containing polyoxyalkylene polymer (A), a method can be applied in which a polyoxyalkylene polymer (d4) (precursor polymer) having an olefin group in its terminal structure is reacted with a compound (d10) having a reactive silicon group and a mercaptan group in one molecule to form a sulfide bond by addition of the mercaptan group to the olefin group, thereby introducing the reactive silicon group.

[0066] The compound (d10) having a reactive silicon group and a mercaptan group in one molecule is not particularly limited as long as it is a compound having both a mercaptan group capable of addition reaction with an olefin group in the polyoxyalkylene polymer (d4) and a reactive silicon group in one molecule. Specific examples include (3-mercaptopropyl)methyldimethoxysilane, (3-mercaptopropyl)trimethoxysilane, (3-mercaptopropyl)methyldiethoxysilane, (3-mercaptopropyl)triethoxysilane, (mercaptomethyl)methyldimethoxysilane, (mercaptomethyl)trimethoxysilane, (mercaptomethyl)methyldiethoxysilane, and (mercaptomethyl)triethoxysilane.

[0067] The addition reaction of a mercaptan group to an olefin group may be carried out without using a radical initiator, but may be carried out in the presence of a radical initiator in order to improve the reaction rate or the reaction rate. As such a radical initiator, a conventionally known initiator can be used. Specific examples include, but are not limited to, azo-based initiators and peroxide-based initiators.

[0068] Among known radical initiators, catalysts with low activity toward reactive silicon groups are preferred, and from this viewpoint, azo-based initiators such as 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (V-59), and 2,2'-azobis(1-methylcyclohexanecarbonitrile) (V-40) are particularly preferred.

[0069] <<Hydrocarbon Diluent (B)>> The curable composition for spray coating according to the present disclosure contains a hydrocarbon diluent (B). By blending the hydrocarbon diluent (B) together with a plasticizer (C) described below, the viscosity of the curable composition for spray coating can be reduced, and spray coatability can be improved.

[0070] The hydrocarbon diluent (B) refers to a compound whose main component is a hydrocarbon compound and which is liquid at room temperature. The hydrocarbon diluent may be either an aromatic hydrocarbon or a non-aromatic hydrocarbon, but from the viewpoint of low odor, a non-aromatic hydrocarbon is preferred.

[0071] From the viewpoint of reducing volatile organic compounds (VOCs) from the curable composition and the cured product obtained by curing the composition, the hydrocarbon diluent (B) is preferably non-volatile. Specifically, the boiling point of the hydrocarbon diluent (B) is preferably 250°C or higher, more preferably 280°C or higher, even more preferably 290°C or higher, and particularly preferably 300°C or higher. When the hydrocarbon diluent (B) has an initial boiling point and an end boiling point, the "boiling point" refers to the initial boiling point.

[0072] Examples of the high-boiling hydrocarbon diluent (B) include naphthenic solvents and paraffinic solvents. These hydrocarbon solvents are preferably hydrogen-treated. These may be used alone or in combination of two or more. The paraffinic solvents referred to here include isoparaffinic solvents.

[0073] Specific examples of the hydrocarbon diluent (B) are not particularly limited, but commercially available products can be used, such as TOTAL FLUID D-170, Hydroseal HY, IP Solvent 2835, and Exol D130. Of these, TOTAL FLUID D-170 and Hydroseal HY are preferred.

[0074] The amount of hydrocarbon diluent (B) is 10 to 50 parts by weight per 100 parts by weight of polyoxyalkylene polymer (A). If the amount of component (B) is less than 10 parts by weight, the viscosity-reducing effect of component (B) is difficult to obtain, spray coating properties are insufficient, spray coating becomes difficult, and the discharge pressure during spray coating must be set high. Furthermore, the coating film obtained by spray coating may have coating spots or the film thickness may be uneven. From the viewpoint of spray coating properties, the amount of component (B) is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, and particularly preferably 40 parts by weight or more.

[0075] On the other hand, if the blending amount of component (B) exceeds 50 parts by weight, the liquid component tends to bleed out from the surface of the cured product obtained by curing the curable composition. Furthermore, after spray coating of the curable composition, the coating film may tend to sag before the composition cures. From the viewpoint of suppressing bleed-out and sagging of the coating film, it is particularly preferable that the blending amount of component (B) is 45 parts by weight or less.

[0076] <<Plasticizer (C)>> The curable composition for spray coating according to the present disclosure contains a plasticizer (C) that is a cyclic hydrocarbon group-containing dicarboxylic acid ester. By blending the plasticizer (C) together with the hydrocarbon diluent (B), the viscosity of the curable composition for spray coating can be reduced, and spray coatability can be improved.

[0077] The plasticizer (C) is a cyclic hydrocarbon group-containing dicarboxylic acid ester. This compound has good compatibility with the hydrocarbon diluent (B), and the two components are easily mixed uniformly, making it difficult for the components to separate in the curable composition, and as a result, the physical properties of the cured film can also be improved.

[0078] The cyclic hydrocarbon group may be an aromatic hydrocarbon group or an alicyclic hydrocarbon group. From the viewpoint of compatibility with the hydrocarbon diluent (B), an alicyclic hydrocarbon group is preferred. An example of an alicyclic hydrocarbon group is a cyclohexane ring.

[0079] Specific examples of the cyclic hydrocarbon group-containing dicarboxylic acid ester include, for alicyclic systems, cyclohexanedicarboxylic acid esters such as 1,2-cyclohexanedicarboxylic acid diisononyl ester (specifically, trade name: Hexamoll DINCH (manufactured by BASF)). For aromatic systems, examples include phthalate esters such as dibutyl phthalate, diisononyl phthalate (DINP), diheptyl phthalate, di(2-ethylhexyl) phthalate, diisodecyl phthalate (DIDP), and butyl benzyl phthalate; and terephthalate esters such as bis(2-ethylhexyl)-1,4-benzenedicarboxylate.

[0080] The blending amount of the plasticizer (C) is 30 parts by weight or more and 90 parts by weight or less per 100 parts by weight of the polyoxyalkylene polymer (A). If the blending amount of the (C) component is less than 30 parts by weight, the viscosity-reducing effect of the blending of the (C) component is difficult to obtain, and the spray coatability may be insufficient. Furthermore, if the blending amount of the (B) component is increased to compensate for the deficiency of the (C) component, the above-mentioned bleed-out is likely to occur. From the viewpoint of spray coatability and bleed-out prevention, the blending amount of the (C) component is preferably 40 parts by weight or more, more preferably 50 parts by weight or more.

[0081] On the other hand, if the blending amount of component (C) exceeds 90 parts by weight, the blending amount of component (B) is relatively reduced, making it difficult to obtain the viscosity-reducing effect of blending component (B), resulting in insufficient spray coatability. Furthermore, the coating film may be prone to sagging. From the viewpoint of spray coatability and suppressing sagging of the coating film, the blending amount of component (C) is preferably 80 parts by weight or less, more preferably 70 parts by weight or less, and even more preferably 60 parts by weight or less.

[0082] The total amount of the hydrocarbon diluent (B) and the plasticizer (C) can be set within the range of the amount of each component described above. From the viewpoint of achieving both good spray coatability and suppression of sagging of the coating film, the total amount is preferably 70 parts by weight or more and 120 parts by weight or less, more preferably 80 parts by weight or more and 110 parts by weight or less, and particularly preferably 85 parts by weight or more and 105 parts by weight or less, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0083] The ratio (C) / (B) of the amount of hydrocarbon diluent (B) to the amount of plasticizer (C) can be set within the range of the amounts of each component described above, but is preferably 0.8 to 3.0 by weight. When (C) / (B) is within this range, the viscosity reduction effect achieved by the combined use of components (B) and (C) achieves good spray coatability while making it easier to avoid bleed-out caused by component (B). It also makes it easier to suppress sagging of the coating film. (C) / (B) is more preferably 0.9 or more, even more preferably 1.0 or more. It is more preferably 2.0 or less, even more preferably 1.5 or less, and particularly preferably 1.2 or less.

[0084] Furthermore, the ratio of the total amount of polyoxyalkylene polymer (A) and plasticizer (C) to the amount of hydrocarbon diluent (B), [(A) + (C)] / (B), can be set within the ranges of the amounts of each component described above, but is preferably 2.6 to 7.0 by weight. When [(A) + (C)] / (B) is within this range, good spray coatability is achieved due to the viscosity reduction effect achieved by blending component (A) with component (B) and component (C), while bleed-out caused by component (B) is easily avoided. Drooping of the coating film is also easily suppressed. [(A) + (C)] / (B) is more preferably 2.8 or more, even more preferably 3.0 or more. It is more preferably 6.0 or less, even more preferably 5.0 or less, and particularly preferably 4.0 or less.

[0085] <<Polyamide-based rheology modifier (D)>> The curable composition for spray coating according to the present disclosure contains a polyamide-based rheology modifier (D). The inclusion of the polyamide-based rheology modifier (D) can prevent sagging of the coating film immediately after spray coating of the curable composition. This improves the appearance of the cured film obtained by curing the coating film, making it possible to form a cured film with uniform physical properties. The polyamide-based rheology modifier is sometimes referred to as a polyamide wax or a fatty acid amide.

[0086] Rheology modifiers other than polyamide-based ones are also commercially available. However, if a non-polyamide-based rheology modifier is used alone without using the polyamide-based rheology modifier (D), it may be difficult to suppress sagging of the coating film, or the viscosity of the curable composition may increase too much, resulting in poor spray coatability.

[0087] As the polyamide-based rheology modifier (D), commercially available products can be used as appropriate, and specific examples include Disparlon (registered trademark) manufactured by Kusumoto Chemicals Co., Ltd., and Crayvallac (registered trademark) SL, Crayvallac (registered trademark) SLX, Crayvallac (registered trademark) SLT, and Crayvallac (registered trademark) SLW manufactured by Arkema Inc. Among them, Crayvallac (registered trademark) SLT is particularly preferred.

[0088] The amount of polyamide rheology modifier (D) is 0.6 parts by weight or more and 7 parts by weight or less per 100 parts by weight of polyoxyalkylene polymer (A). If the amount of component (C) is less than 0.6 parts by weight, the effect of suppressing sagging of the coating film will be insufficient. It is preferably 0.7 parts by weight or more, more preferably 1 part by weight or more, and even more preferably 2 parts by weight or more. If it exceeds 7 parts by weight, the viscosity of the curable composition may increase too much, resulting in reduced spray applicability. It is preferably 6 parts by weight or less, and more preferably 5 parts by weight or less.

[0089] The curable composition for spray coating according to the present disclosure may contain only the polyamide-based rheology modifier (D) as the rheology modifier, or may contain, in addition to the polyamide-based rheology modifier (D), a rheology modifier other than component (D). In such cases, the amount of the rheology modifier other than component (D) is preferably equal to or less than the amount of component (D).

[0090] <<Filler (E)>> The curable composition for spray coating according to the present disclosure preferably contains a filler (E) from the viewpoint of improving the strength of the cured film. The filler (E) is not particularly limited, but examples thereof include heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, clay, talc, titanium oxide, fumed silica, precipitated silica, crystalline silica, fused silica, silicic anhydride, hydrous silicic acid, alumina, carbon black, ferric oxide, aluminum fine powder, zinc oxide, activated zinc white, PVC powder, PMMA powder, glass fiber and filament, etc. Furthermore, organic balloons and inorganic balloons can also be used to reduce the weight (specific gravity) of the composition. Only one type of filler (E) may be used, or two or more types may be used in combination.

[0091] It is preferable to use calcium carbonate as the filler (E) because the viscosity of the curable composition tends to be less likely to increase and spray coatability tends to be better. As calcium carbonate, heavy calcium carbonate and light calcium carbonate can be used, but heavy calcium carbonate is more preferable from the viewpoint of achieving both spray coatability and suppression of sagging of the coating film. Here, heavy calcium carbonate refers to calcium carbonate obtained by pulverizing and classifying limestone.

[0092] Furthermore, it is particularly preferable to use surface-treated heavy calcium carbonate as the heavy calcium carbonate. In this case, the type of surface treatment agent is not particularly limited, but an organic material is preferable, and a fatty acid or a fatty acid ester is particularly preferable. Commercially available products are available as such surface-treated heavy calcium carbonate.

[0093] When filler (E) is blended, the blending amount may be, for example, about 10% by weight or more and 50% by weight or less, but preferably 20% by weight or more and 40% by weight or less, based on a total amount (100% by weight) of the curable composition for spray coating according to the present disclosure. When the blending amount of filler (E) is within this range, the spray coatability of the curable composition can be maintained within a good range while achieving the strength-improving effect achieved by blending component (E). In addition, sagging of the coating film can be easily suppressed. A blending amount of 25% by weight or more and 35% by weight or less is more preferred.

[0094] When calcium carbonate is used as the filler (E), calcium carbonate may be used alone, or calcium carbonate may be used in combination with other fillers. From the viewpoint of spray coating properties, the content of calcium carbonate in the entire filler (E) is preferably 30 to 100% by weight, more preferably 60 to 100% by weight, and particularly preferably 80 to 100% by weight.

[0095] <<Curing Catalyst (F)>> The curable composition for spray coating according to the present disclosure preferably contains a curing catalyst (F) (also referred to as a silanol condensation catalyst) to hydrolyze and condense the reactive silicon groups of the polyoxyalkylene polymer (A) and promote the curing reaction of the curable composition.

[0096] Examples of the curing catalyst (F) include organotin compounds, metal carboxylates, amine compounds, carboxylic acids, and alkoxy metals.

[0097] Specific examples of organotin compounds include dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin bis(butyl maleate), dibutyltin diacetate, dibutyltin oxide, dibutyltin bis(acetylacetonate), dioctyltin bis(acetylacetonate), dioctyltin dilaurate, dioctyltin distearate, dioctyltin diacetate, dioctyltin oxide, a reaction product of dibutyltin oxide with a silicate compound, a reaction product of dioctyltin oxide with a silicate compound, and a reaction product of dibutyltin oxide with a phthalate ester.

[0098] Specific examples of metal carboxylates include tin carboxylate, bismuth carboxylate, titanium carboxylate, zirconium carboxylate, iron carboxylate, potassium carboxylate, calcium carboxylate, etc. The carboxylic acid group can be a combination of the following carboxylic acids with various metals. Specifically, iron 2-ethylhexanoate (divalent), iron 2-ethylhexanoate (trivalent), titanium 2-ethylhexanoate (tetravalent), vanadium 2-ethylhexanoate (trivalent), calcium 2-ethylhexanoate (divalent), potassium 2-ethylhexanoate (monovalent), barium 2-ethylhexanoate (divalent), manganese 2-ethylhexanoate (divalent), nickel 2-ethylhexanoate (divalent), cobalt 2-ethylhexanoate (divalent), zirconium 2-ethylhexanoate (tetravalent), iron neodecanoate (divalent), iron neodecanoate (trivalent), titanium neodecanoate (tetravalent), vanadium neodecanoate (trivalent), calcium neodecanoate (divalent), potassium neodecanoate (monovalent), barium neodecanoate (divalent), di-ethylhexanoate Examples of suitable oleic acids include zinc (tetravalent), iron oleate (divalent), iron oleate (trivalent), titanium oleate (tetravalent), vanadium oleate (trivalent), calcium oleate (divalent), potassium oleate (monovalent), barium oleate (divalent), manganese oleate (divalent), nickel oleate (divalent), cobalt oleate (divalent), zirconium oleate (tetravalent), iron naphthenate (divalent), iron naphthenate (trivalent), titanium naphthenate (tetravalent), vanadium naphthenate (trivalent), calcium naphthenate (divalent), potassium naphthenate (monovalent), barium naphthenate (divalent), manganese naphthenate (divalent), nickel naphthenate (divalent), cobalt naphthenate (divalent), and zirconium naphthenate (tetravalent).

[0099] Specific examples of the amine compound include amines such as octylamine, 2-ethylhexylamine, laurylamine, and stearylamine; nitrogen-containing heterocyclic compounds such as pyridine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), and 1,5-diazabicyclo[4,3,0]nonene-5 (DBN); guanidines such as guanidine, phenylguanidine, and diphenylguanidine; biguanides such as butylbiguanide, 1-o-tolylbiguanide, and 1-phenylbiguanide; amino group-containing silane coupling agents; and ketimine compounds.

[0100] Specific examples of carboxylic acids include acetic acid, propionic acid, butyric acid, 2-ethylhexanoic acid, lauric acid, stearic acid, oleic acid, linoleic acid, neodecanoic acid, and versatic acid.

[0101] Specific examples of alkoxy metals include titanium compounds such as tetrabutyl titanate titanium tetrakis(acetylacetonate) and diisopropoxytitanium bis(ethylacetoacetate), aluminum compounds such as aluminum tris(acetylacetonate) and diisopropoxyaluminum ethylacetoacetate, and zirconium compounds such as zirconium tetrakis(acetylacetonate).

[0102] In addition, a fluorine anion-containing compound, a photoacid generator, or a photobase generator can also be used as the curing catalyst (F).

[0103] Two or more different types of curing catalysts (F) may be used in combination. The amount of the curing catalyst (F) added is preferably 0.001 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, and particularly preferably 0.1 to 10 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0104] <<Other Components>> In addition to the reactive silicon group-containing polyoxyalkylene polymer (A), hydrocarbon diluent (B), plasticizer (C), polyamide rheology modifier (D), filler (E), and curing catalyst (F), the curable composition for spray coating according to the present disclosure may contain additives such as adhesion promoters, antioxidants, light stabilizers, UV absorbers, physical property modifiers, tackifier resins, epoxy group-containing compounds, photocurable substances, oxygen-curable substances, epoxy resins, and other resins. Furthermore, various additives may be added to the curable composition for spray coating according to the present disclosure as needed to adjust the physical properties of the curable composition or the cured product. Examples of such additives include surface property modifiers, foaming agents, curability modifiers, flame retardants, silicates, radical inhibitors, metal deactivators, antiozonants, phosphorus-based peroxide decomposers, lubricants, pigments, and mildew inhibitors.

[0105] <Adhesion Imparting Agent> The curable composition for spray coating according to the present disclosure may be blended with an adhesion imparting agent. As the adhesion imparting agent, a silane coupling agent or a reaction product of a silane coupling agent may be used.

[0106] Specific examples of the silane coupling agent include amino group-containing silanes such as γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and (2-aminoethyl)aminomethyltrimethoxysilane; γ-isocyanatepropyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, and γ-isopropyltriethoxysilane; Examples of suitable silanes include isocyanate group-containing silanes such as cyanate propyl methyl dimethoxy silane, α-isocyanate methyl trimethoxy silane, and α-isocyanate methyl dimethoxy methyl silane; mercapto group-containing silanes such as γ-mercapto propyl trimethoxy silane, γ-mercapto propyl triethoxy silane, and γ-mercapto propyl methyl dimethoxy silane; and epoxy group-containing silanes such as γ-glycidoxy propyl trimethoxy silane and β-(3,4-epoxycyclohexyl) ethyl trimethoxy silane.

[0107] Also usable are condensates of various silane coupling agents such as condensates of aminosilane, condensates of aminosilane and other alkoxysilanes, and reaction products of various silane coupling agents such as reaction products of aminosilane and epoxysilane, reaction products of aminosilane and (meth)acrylic group-containing silane, etc. Specific examples include Dynasylan 1146 and Dynasylan 1124 (manufactured by EVONIK).

[0108] The amount of the silane coupling agent to be added is preferably 0.1 to 20 parts by weight, particularly preferably 0.5 to 10 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0109] <Antioxidant> The curable composition for spray coating according to the present disclosure can be blended with an antioxidant (antiaging agent). The use of an antioxidant can improve the weather resistance of the cured product. Examples of antioxidants include hindered phenols, monophenols, bisphenols, and polyphenols. Examples include BHT, Irganox 245, Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1135, Irganox 1330, Irganox 1520, and SONGNOX 1076. Similarly, hindered amine light stabilizers such as TINUVIN 622LD, TINUVIN 144, and TINUVIN 292; CHIMASSORB 944LD and CHIMASSORB 119FL (all manufactured by BASF); ADK STAB LA-57, ADK STAB LA-62, ADK STAB LA-67, ADK STAB LA-63, and ADK STAB LA-68 (all manufactured by ADEKA Corporation); SANOL LS-2626, SANOL LS-1114, and SANOL LS-744 (all manufactured by Sankyo Lifetech Co., Ltd.); and NOCRAC CD (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) can also be used. Other antioxidants that can be used include SONGNOX 4120, NAUGUARD 445, and OKABEST CLX050.

[0110] Specific examples of antioxidants are also described in Japanese Patent Application Laid-Open Nos. 4-283259 and 9-194731.

[0111] The amount of the antioxidant to be added is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0112] <Light Stabilizer> A light stabilizer can be blended into the curable composition for spray coating according to the present disclosure. Blending a light stabilizer can prevent photooxidative degradation of the cured product. Examples of light stabilizers include benzotriazole-based, hindered amine-based, and benzoate-based compounds, with hindered amine-based compounds being particularly preferred.

[0113] Examples of hindered amine light stabilizers include TINUVIN 123, TINUVIN 144, TINUVIN 249, TINUVIN 292, TINUVIN 312, TINUVIN 622LD, TINUVIN 765, TINUVIN 770, TINUVIN 880, TINUVIN 5866, and TINUVIN B97; CHIMASSORB 119FL and CHIMASSORB 944LD (all manufactured by BASF); ADK STAB LA-57, LA-62, LA-63, LA-67, and LA-68 (all manufactured by ADEKA Corporation); SANOL LS-292, LS-2626, LS-765, LS-744, and LS-1114 (all manufactured by Sankyo Lifetech Co., Ltd.); SABOSTAB UV91 and SABOSTAB Examples of light stabilizers include UV119, SONGSORB CS5100, SONGSORB CS622, SONGSORB CS944 (all manufactured by SONGWON), and NOCRAC CD (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.).

[0114] The amount of the light stabilizer to be added is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0115] <Ultraviolet Absorber> The curable composition for spray coating according to the present disclosure may contain an ultraviolet absorber. Adding an ultraviolet absorber can improve the surface weather resistance of the cured product. Examples of ultraviolet absorbers include benzophenone-based, benzotriazole-based, salicylate-based, triazine-based, substituted acrylonitrile-based, and metal chelate-based compounds, with benzotriazole-based compounds being particularly preferred. Examples include TINUVIN 234, TINUVIN 326, TINUVIN 327, TINUVIN 328, TINUVIN 329, TINUVIN 350, TINUVIN 571, TINUVIN 900, TINUVIN 928, TINUVIN 1130, and TINUVIN 1600 (all manufactured by BASF); and SONGSORB 3290 (manufactured by SONGWON). Examples of triazine compounds include TINUVIN 400, TINUVIN 405, TINUVIN 477, and TINUVIN 1577ED (all manufactured by BASF), SONGSORB CS400 and SONGSORB 1577 (manufactured by SONGWON), etc. Examples of benzophenone compounds include SONGSORB 8100 (manufactured by SONGWON).

[0116] The amount of the ultraviolet absorber to be added is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0117] Addworks IBC760 (manufactured by Clariant) can also be used as a product containing an antioxidant, a light stabilizer, and an ultraviolet absorber.

[0118] <Physical Property Adjuster> The curable composition for spray coating according to the present disclosure may contain a physical property adjuster that adjusts the tensile properties of the cured product. The physical property adjuster is not particularly limited, but examples include alkylalkoxysilanes such as phenoxytrimethylsilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, and n-propyltrimethoxysilane; arylalkoxysilanes such as diphenyldimethoxysilane and phenyltrimethoxysilane; alkylisopropenoxysilanes such as dimethyldiisopropenoxysilane, methyltriisopropenoxysilane, and γ-glycidoxypropylmethyldiisopropenoxysilane; trialkylsilylborates such as tris(trimethylsilyl)borate and tris(triethylsilyl)borate; silicone varnishes; and polysiloxanes. The use of such a physical property adjuster can increase the hardness of the curable composition for spray coating according to the present disclosure when cured, or conversely, decrease the hardness and increase the elongation at break. The physical property adjusting agents may be used alone or in combination of two or more kinds.

[0119] In particular, compounds that produce a compound having a monovalent silanol group in the molecule upon hydrolysis have the effect of reducing the modulus of the cured product without increasing the stickiness of the surface of the cured product. Compounds that produce trimethylsilanol are particularly preferred. Examples of compounds that produce a compound having a monovalent silanol group in the molecule upon hydrolysis include silicon compounds that are derivatives of alcohols such as hexanol, octanol, phenol, trimethylolpropane, glycerin, pentaerythritol, and sorbitol and that produce silane monool upon hydrolysis. Specific examples include phenoxytrimethylsilane and tris((trimethylsiloxy)methyl)propane.

[0120] The amount of the physical property adjuster to be added is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0121] <Tackifying Resin> A tackifying resin may be blended into the curable composition for spray coating according to the present disclosure for the purpose of improving adhesion and cohesion to a substrate. There are no particular limitations on the tackifying resin, and any commonly used tackifying resin can be used.

[0122] Specific examples include terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene-phenol resins, phenol resins, modified phenol resins, xylene-phenol resins, cyclopentadiene-phenol resins, coumarone-indene resins, rosin resins, rosin ester resins, hydrogenated rosin ester resins, xylene resins, low molecular weight polystyrene resins, styrene copolymer resins, styrene block copolymers and hydrogenated products thereof, petroleum resins (e.g., C5 hydrocarbon resins, C9 hydrocarbon resins, C5C9 hydrocarbon copolymer resins, etc.), hydrogenated petroleum resins, DCPD resins, etc. These may be used alone or in combination of two or more.

[0123] The amount of the tackifier resin to be added is preferably 2 to 100 parts by weight, more preferably 5 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0124] <Compound containing an epoxy group> The curable composition for spray coating according to the present disclosure can be blended with a compound containing an epoxy group. Blending a compound containing an epoxy group can improve the recovery properties of the cured product. Examples of compounds containing an epoxy group include epoxidized unsaturated fats and oils, epoxidized unsaturated fatty acid esters, alicyclic epoxy compounds, epichlorohydrin derivatives, and mixtures thereof. Specific examples include epoxidized soybean oil, epoxidized linseed oil, bis(2-ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate (E-PS), epoxy octyl stearate, and epoxy butyl stearate. The epoxy compound is preferably blended in an amount ranging from 0.5 to 50 parts by weight per 100 parts by weight of the polyoxyalkylene polymer (A).

[0125] <Photocurable Substance> A photocurable substance can be blended into the curable composition for spray coating according to the present disclosure. By blending a photocurable substance, a film of the photocurable substance is formed on the surface of the cured product, improving the stickiness and weather resistance of the cured product. Many compounds of this type are known, including organic monomers, oligomers, resins, and compositions containing them. Representative examples include unsaturated acrylic compounds, which are monomers or oligomers having one or more acrylic or methacrylic unsaturated groups, or mixtures thereof, polyvinyl cinnamates, and azido resins.

[0126] The amount of the photocurable substance to be added is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0127] <Oxygen-Curable Substance> The curable composition for spray coating according to the present disclosure can contain an oxygen-curable substance. Examples of oxygen-curable substances include unsaturated compounds that can react with oxygen in the air to form a cured film near the surface of the cured product, thereby preventing surface stickiness and preventing the adhesion of dirt and dust to the surface of the cured product. Specific examples of oxygen-curable substances include drying oils such as tung oil and linseed oil, and various alkyd resins obtained by modifying such compounds; acrylic polymers, epoxy resins, and silicone resins modified with drying oils; and liquid polymers such as 1,2-polybutadiene, 1,4-polybutadiene, and polymers of C5 to C8 dienes obtained by polymerizing or copolymerizing diene compounds such as butadiene, chloroprene, isoprene, and 1,3-pentadiene. These substances may be used alone or in combination of two or more.

[0128] The amount of the oxygen-curable substance to be blended is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A). As described in JP-A-3-160053, the oxygen-curable substance is preferably used in combination with a photo-curable substance.

[0129] <Epoxy Resin> The curable composition for spray coating according to the present disclosure may be used in combination with an epoxy resin, such as bisphenol A epoxy resins or novolac epoxy resins.

[0130] The ratio of the epoxy resin to the polyoxyalkylene polymer (A) used is preferably in the range of (A) / epoxy resin=100 / 1 to 1 / 100 by weight.

[0131] When an epoxy resin is blended, it is preferable to blend a curing agent for curing the epoxy resin in the curable composition for spray coating according to the present disclosure. There are no particular restrictions on the epoxy resin curing agent that can be used, and commonly used epoxy resin curing agents can be used.

[0132] When an epoxy resin curing agent is added, the amount added is preferably in the range of 0.1 to 300 parts by weight per 100 parts by weight of the epoxy resin.

[0133] <<Viscosity of Curable Composition for Spray Coating>> The curable composition for spray coating according to the present disclosure has good spray coatability and therefore has a low viscosity when the composition is spray coated by applying pressure. Therefore, it is preferable that the viscosity measured in the high shear region is low. Specifically, the viscosity measured at a temperature of 23°C and a shear rate of 2000 / sec is preferably 1.5 Pa·s or less. More preferably, it is 1.4 Pa·s or less. The lower limit is not particularly limited, but may be, for example, 0.1 Pa·s or more, preferably 0.5 Pa·s or more, and more preferably 1.0 Pa·s or more.

[0134] On the other hand, the curable composition for spray coating according to the present disclosure has the property of being less likely to drip after coating. Therefore, it is preferable that the viscosity measured in the low shear region exhibits a high value. Specifically, the viscosity measured at a temperature of 23°C and a shear rate of 2 / sec is preferably 4 Pa·s or more, more preferably 6 Pa·s or more, and even more preferably 8 Pa·s or more. The upper limit is not particularly limited, but may be, for example, 30 Pa·s or less, preferably 20 Pa·s or less, and more preferably 15 Pa·s or less.

[0135] As will be described in detail in the Examples below, the viscosity measured at a shear rate of 2 / sec is preferably measured at 2 / sec when the shear rate is increased from 0.1 / sec to 2000 / sec and then decreased from 2000 / sec to 0.1 / sec. The decrease in 2 / sec is a low shear region after the application of a strong shear force, and is therefore thought to be close to the viscosity of the composition in the coating film immediately after spray coating.

[0136] <<Preparation of Curable Composition for Spray Coating>> The curable composition for spray coating according to the present disclosure can be prepared as a one-component composition in which all ingredients are blended in advance and stored in a sealed container, and the composition is cured by moisture in the air after application. Alternatively, the composition can be prepared as a two-component composition in which ingredients such as a curing catalyst, a filler, a plasticizer, and water are blended separately as a curing agent, and the composition containing the ingredients and the polymer (A) are mixed before use. From the viewpoint of workability, the one-component composition is preferred.

[0137] When the curable composition is a one-component type, all of the components are blended in advance, and therefore it is preferable to dehydrate and dry the components containing water before use, or to dehydrate them by reducing the pressure during blending and kneading. In addition to the dehydration and drying method, the storage stability can be further improved by adding an alkoxysilane compound such as n-propyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, vinylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, or γ-glycidoxypropyltrimethoxysilane as a dehydrating agent.

[0138] The amount of the dehydrating agent, particularly the silicon compound capable of reacting with water such as vinyltrimethoxysilane, is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the polyoxyalkylene polymer (A).

[0139] <<Uses of Curable Composition for Spray Coating>> The curable composition for spray coating according to the present disclosure is used to spray-coat the surface of a substrate, and then cure it to form a cured film. The equipment used for spray coating is not particularly limited, and examples include an air spray device that atomizes the paint by applying air pressurized by a compressor to the paint; an airless spray device that atomizes the paint by applying pressure to the paint and spraying it from a nozzle without using air; an HVLP spray device that atomizes the paint using a large volume of air at low pressure; and an electrostatic spray device that electrically charges the paint.

[0140] For efficient spray coating over a wide area of ​​a large substrate, such as the exterior wall of a building, it is preferable to use an airless spray device. The curable composition for spray coating according to the present disclosure can be suitably spray coated using an airless spray device, and in this case, the spray coatability is good. Furthermore, good spray coatability can be achieved even when the discharge pressure of the airless spray device is set to a relatively low range.

[0141] The discharge pressure (also referred to as atomization pressure) of the airless spray device can be set appropriately, but may be, for example, within the range of 0.5 to 20 MPa. The lower limit is preferably 5 MPa or more, more preferably 10 MPa or more, and even more preferably 15 MPa or more.

[0142] The substrate to which the curable composition for spray coating according to the present disclosure is applied is not particularly limited, and examples include the exterior walls, roofs, and rooftops of buildings. In particular, it can be used to form a film that seamlessly covers the entire exterior wall material. Such a film can function as a waterproof film. That is, the curable composition for spray coating according to the present disclosure can be used to form a waterproof film on the surface of a substrate by spray coating. Since a cured product of the polyoxyalkylene polymer (A) generally exhibits moisture permeability, the waterproof film can function as a moisture-permeable waterproof film. Note that the use as a waterproof film described here differs from the use as a sealant for filling gaps and joints in a substrate.

[0143] The material constituting the substrate is not particularly limited, but examples thereof include porous materials such as siding boards, concrete, CMU backup walls, mortar, stone, and metal.

[0144] The conditions for curing the coating film are not particularly limited, and for example, after spray coating, the coating film may be left at room temperature for about 1 to 5 days.

[0145] The thickness of the cured film formed on the surface of the substrate is not particularly limited, but may be, for example, within a range of about 100 μm to 4 mm, preferably about 200 μm to 3 mm, and more preferably about 200 μm to 2 mm.

[0146] The following items list preferred embodiments of the present disclosure, but the present invention is not limited to them. [Item 1] A curable composition for spray coating, comprising: 100 parts by weight of a polyoxyalkylene polymer (A) having a reactive silicon group; 10 to 50 parts by weight of a hydrocarbon diluent (B); 30 to 90 parts by weight of a plasticizer (C) that is a cyclic hydrocarbon group-containing dicarboxylic acid ester; and 0.6 to 7 parts by weight of a polyamide rheology modifier (D). [Item 2] The curable composition according to Item 1, wherein the hydrocarbon diluent (B) comprises at least one selected from the group consisting of naphthenic diluents and paraffinic diluents. [Item 3] The curable composition according to Item 1 or 2, wherein the hydrocarbon diluent (B) has a boiling point of 250°C or higher. [Item 4] The curable composition according to any one of Items 1 to 3, further comprising a filler (E), wherein the content of the filler (E) is 20 to 40% by weight relative to 100% by weight of the total amount of the curable composition. [Item 5] The curable composition according to Item 4, wherein the filler (E) comprises calcium carbonate. [Item 6] The curable composition according to Item 5, wherein the calcium carbonate is surface-treated ground calcium carbonate. [Item 7] The curable composition according to any one of Items 1 to 6, wherein the ratio of the plasticizer (C) to the hydrocarbon diluent (B), (C) / (B), is 0.8 to 3.0 by weight. [Item 8] The curable composition according to any one of Items 1 to 7, wherein the ratio of the sum of the polyoxyalkylene polymer (A) and the plasticizer (C), ((A)+(C)] / (B), is 2.6 to 7.0 by weight. [Item 9] The curable composition according to any one of items 1 to 8, wherein the average number of reactive silicon groups per terminal of the polyoxyalkylene polymer (A) is 0.85 or more. [Item 10] The curable composition according to any one of items 1 to 9, wherein the viscosity of the curable composition measured at a temperature of 23°C and a shear rate of 2 / sec is 4 Pa ​​s or more. [Item 11] The curable composition according to any one of items 1 to 10, wherein the viscosity of the curable composition measured at a temperature of 23°C and a shear rate of 2000 / sec is 1.5 Pa s or less.[Item 12] A cured film obtained by spray coating and curing the curable composition according to any one of items 1 to 11. [Item 13] A method for producing a cured film, comprising spray coating the curable composition according to any one of items 1 to 11 onto a surface of a substrate and then curing the composition.

[0147] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0148] (Number Average Molecular Weight) The number average molecular weight in the examples is a GPC molecular weight measured under the following conditions: Solution delivery system: HLC-8220GPC manufactured by Tosoh Corporation Column: TSKgel Super H series manufactured by Tosoh Corporation Solvent: THF Molecular weight: polystyrene equivalent Measurement temperature: 40°C

[0149] The end group-based molecular weight in the examples is a molecular weight calculated by determining the hydroxyl value according to the measurement method of JIS K 1557 and the iodine value according to the measurement method of JIS K 0070, taking into consideration the structure of the organic polymer (the degree of branching determined by the polymerization initiator used).

[0150] The average number of silyl groups introduced per terminal or per molecule of the polymers shown in the examples was calculated by NMR measurement.

[0151] Synthesis Example 1 A-1: ​​Using polyoxypropylene glycol having a number-average molecular weight of approximately 4,500 as an initiator, propylene oxide was polymerized in the presence of a zinc hexacyanocobaltate glyme complex catalyst to obtain a terminal hydroxyl-containing polyoxypropylene (P-1) having a number-average molecular weight of 14,300 (terminal-based molecular weight of 9,132) and a molecular weight distribution Mw / Mn = 1.21. To the hydroxyl-terminated polyoxypropylene (P-1) obtained, 1.2 molar equivalents of sodium methoxide were added as a 28% methanol solution relative to the hydroxyl groups. After distilling off the methanol by vacuum devolatilization, an additional 1.5 molar equivalents of allyl chloride relative to the hydroxyl groups of the polymer (P-1) were added to convert the terminal hydroxyl groups to allyl groups. Unreacted allyl chloride was removed by vacuum devolatilization. The resulting crude polyoxypropylene was mixed with n-hexane and water and stirred, followed by centrifugation to remove the water. The hexane was then devolatilized under reduced pressure from the resulting hexane solution to remove metal salts from the polymer. This yielded polyoxypropylene (Q-1) having allyl groups at its termini. 50 μl of a platinum divinyldisiloxane complex solution (a 3 wt % platinum equivalent isopropanol solution) was added to 500 g of this polymer (Q-1), and 8.4 g of dimethoxymethylsilane was slowly added dropwise while stirring. After reacting at 100°C for 2 hours, unreacted dimethoxymethylsilane was distilled off under reduced pressure to yield polyoxypropylene (A-1) having terminal dimethoxymethylsilyl groups and a number-average molecular weight of 14,600. It was found that polymer (A-1) contained an average of 0.8 dimethoxymethylsilyl groups at each terminus and an average of 1.5 per molecule.

[0152] Synthesis Example 2 A-2 To polymer (Q-1), 50 ppm of (bicyclo[2.2.1]hepta-2,5-diene)dichlororuthenium(II) polymer (Sigma-Aldrich) and 130 ppm of 2,3-dibromonorbornadiene were added, and the mixture was stirred at 90°C for 10 minutes. Furthermore, 4.0 molar equivalents of dimethoxymethylsilane relative to the allyl groups in polymer (Q-1) were added, and the mixture was stirred for 1 hour. Volatile components were removed by distillation under reduced pressure to obtain polyoxypropylene (A-2) having terminal dimethoxymethylsilyl groups and a number-average molecular weight of 14,600. It was found that polymer (A-2) had an average of 0.93 dimethoxymethylsilyl groups per terminal.

[0153] (Examples 1 to 7, Comparative Examples 1 to 3, Reference Examples 1 and 2) According to the compositions (weight ratios) shown in Table 1, polymer (A-1) was first mixed with a plasticizer, a diluent, a filler (calcium carbonate and titanium oxide), a polyamide-based rheology modifier, an ultraviolet absorber, and a light stabilizer, and the mixture was stirred using a planetary centrifugal stirring / degassing mixer (manufactured by Samsung Industries Co., Ltd., product name: Hi-Rotor HR005-04V). After cooling the mixture to 50°C or below, A-171 (manufactured by Momentive Performance Materials Holdings Inc.: vinyltrimethoxysilane) as a dehydrating agent, A-1120 (manufactured by Momentive Performance Materials Holdings Inc.: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane) as an adhesion promoter, and Neostan U-220H (manufactured by Nitto Kasei Co., Ltd.: dibutyltin bisacetylacetonate) as a curing catalyst were sequentially added thereto, and the mixture was thoroughly mixed with a spatula. After that, the mixture was stirred and degassed using a planetary centrifugal stirring and degassing mixer to obtain a curable composition. When preparing the curable composition subjected to the spray coatability test, stirring was carried out using a 50 L twin-screw mixer (manufactured by Inoue Seisakusho).

[0154] (Bleeding Test) The obtained curable composition was filled into a mold with an inner diameter of 40 mm and a depth of 10 mm, and the surface was smoothed. After curing under conditions of 23°C and a relative humidity of 50%, the composition was left at 5°C (without controlling the relative humidity) for the number of days listed in Table 1. When the surface of the cured product was touched with a finger, if the liquid compound did not adhere to the hand, the bleed was evaluated as "No" (absent), and if the liquid compound adhered to the hand, the bleed was evaluated as "Yes" (present). The results are shown in Table 1.

[0155] (Spray Coatability Test) The spray coatability of the obtained curable compositions was evaluated at a spray pressure of 14 MPa using a Graco Mark V electric airless sprayer equipped with a #531 spray tip. The hose length was 30 m. The coating was evaluated based on the presence or absence of coating mottles on the coated surface when the coating was sprayed once horizontally over a distance of approximately 110 cm while maintaining a distance of approximately 50 cm between the coated surface and the spray nozzle. "Coating mottles" here refers to the appearance of streaks in uncoated areas. Coatings that showed coating mottles were evaluated as "x", and those that did not were evaluated as "○". The results are shown in Table 1.

[0156] The terms used in Tables 1 to 4 are explained as follows: DINP (J-Plus Corporation: diisononyl phthalate) DINCH (BASF: 1,2-cyclohexanedicarboxylic acid diisononyl ester) Total Fluid D170 (Total Energy: hydrogen-treated light paraffin oil) Hydroseal HY (Total Energy: hydrogen-treated light paraffin oil) Hakuenka CCR (Shiraishi Kogyo Co., Ltd.: precipitated calcium carbonate) Whiten SB (Shiraishi Calcium Co., Ltd.: heavy calcium carbonate) Omyacarb 1T-JI (Omya: heavy calcium carbonate, average particle size (D50): 1.8 μm) Omyacarb 2T-JI (Omya: heavy calcium carbonate, average particle size (D50): 2.8 μm) Omyacarb 5T-JI (Omya: heavy calcium carbonate, average particle size (D50): 4.9 μm) Typaque R-820 (Ishihara Sangyo Kaisha, Ltd.: rutile-type titanium dioxide) Crayvallac SLT (ARKEMA: polyamide-based rheology modifier) ​​Crayvallac SLW (ARKEMA: polyamide-based rheology modifier) ​​Viscoexcel-30 (Shiraishi Kogyo Co., Ltd.: synthetic calcium carbonate) Aerosil R974 (Nippon Aerosil: fumed silica) BYK-R 606 (BYK: non-polyamide-based rheology modifier) ​​10 wt% CNFsol. (10 wt% DINP dispersion of cellulose nanofiber) TEG2EH (Shandong Kexing Chemical Co., Ltd.: triethylene glycol bis(2-ethylhexanoate)) Tinuvin 328 (BASF: benzotriazole-based ultraviolet absorber) Tinuvin 770 (BASF: hindered amine-based light stabilizer)

[0157]

[0158] As shown in Table 1, in Examples 1 to 7, in which the amount of hydrocarbon diluent (B) was in the range of 10 to 50 parts by weight, no bleeding from the cured product was observed at either room temperature or low temperatures, whereas in Comparative Examples 1 to 3, in which the amount of hydrocarbon diluent (B) exceeded 50 parts by weight, bleeding was observed at low temperatures. Furthermore, spray coatability was also evaluated for Examples 1 and 2, and was found to be good. On the other hand, Reference Examples 1 and 2 show evaluation results for cases in which no hydrocarbon diluent (B) was blended. Although no bleeding was observed in these Reference Examples, coating unevenness occurred on the coated surface, and spray coatability was poor.

[0159] (Examples 8 to 15, Comparative Examples 4 to 9, Reference Examples 3 to 12) According to the compositions (weight ratios) shown in Tables 2 and 3, first, polymer (A-1) or (A-2) was mixed with a plasticizer, a diluent, a filler (calcium carbonate and titanium oxide), various rheology modifiers, an ultraviolet absorber, and a light stabilizer, and the mixture was stirred using a planetary centrifugal stirring / degassing mixer (manufactured by Samsung Industries Co., Ltd., product name: Hi-Rotor HR005-04V). The mixture was cooled to 50°C or lower, and then A-171 (vinyltrimethoxysilane, manufactured by Momentive Performance Materials Holdings Inc.) as a dehydrating agent, A-1120 (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, manufactured by Momentive Performance Materials Holdings Inc.) as an adhesion promoter, and Neostan U-220H (dibutyltin bisacetylacetonate, manufactured by Nitto Kasei Co., Ltd.) as a curing catalyst were sequentially added thereto, and the mixture was thoroughly mixed with a spatula, followed by stirring and defoaming using a planetary centrifugal stirring and defoaming mixer to obtain a curable composition.

[0160] (Viscosity) The viscosity of the resulting curable composition was measured using a Hybrid Rheometer Discovery HR-2 manufactured by TA Instruments. The plate diameter was adjusted to 20 mm, the gap between the plate and the sample stage was adjusted to 0.5 mm, and the sample stage temperature was set to 23°C. The shear rate was changed from 0.1 / s to 2000 / s over 4 minutes (ascending shear rate), and then changed from 2000 / s to 0.1 / s over the next 4 minutes (descending shear rate). The spray properties of the curable composition were evaluated based on the viscosity at 2000 / s (ascending) and 2 / s (descending).

[0161] The viscosity at 2000 / s (Ascending) is in the high shear region and is therefore thought to be close to the viscosity at the time of spray discharge, and compositions with a low viscosity value were evaluated as having good spray applicability (i.e., good workability). Also, the viscosity at 2 / s (Descending) is in the low shear region after the application of a strong shear force and is therefore thought to be close to the viscosity of the composition in the coating film immediately after spray coating, and the higher this value, the less likely the composition is to drip after coating (i.e., the better the finish after coating).

[0162] (Tensile Properties) The obtained curable composition was filled into a mold and aged for 3 days at 23°C and 50% relative humidity, and then for 4 days at 50°C to produce a sheet-like cured product approximately 3 mm thick. The sheet-like cured product was punched out into a No. 3 dumbbell shape and subjected to a tensile test in an atmosphere of 23°C and 50% relative humidity to measure the stress at 50% and 100% elongation (M50, M100) and the breaking strength. The measurement was performed using an autograph (AGS-J, manufactured by Shimadzu Corporation) at a tensile speed of 500 mm / min.

[0163]

[0164] As shown in Table 2, Examples 8 to 15, which used a polyamide-based rheology modifier, exhibited viscosities within the desired range at 2000 / s (Ascending) and 2 / s (Descending), achieving both spray coatability and resistance to sagging after coating. Specifically, Examples 8 to 15 exhibited viscosities within the range of 1.2 to 1.5 Pa·s at 2000 / s (Ascending), and viscosities of 4.1 Pa·s or higher at 2 / s (Descending). In other words, because they exhibit low viscosity during spray coating, they can be applied at relatively low pressure using a spray coater, providing excellent workability. Furthermore, after being applied to the substrate surface by spray coating, they exhibited a moderately high viscosity, resistance to sagging, and a good finish after coating.

[0165] On the other hand, Comparative Example 4, which contained a high amount of polyamide-based rheology modifier (10 parts by weight), and Comparative Examples 5 to 7, which used a rheology modifier that was not polyamide-based, exhibited a viscosity of 1.7 Pa·s or more at 2000 s (Ascending), necessitating the application of high pressure when applying using a spray coater, and workability was not satisfactory. Comparative Example 8, which also used a rheology modifier that was not polyamide-based, exhibited an extremely low viscosity of less than 2 Pa·s at 2 s (Descending), which made the coating prone to dripping after application and made it difficult to achieve a clean finish. Furthermore, Comparative Example 9, which used a plasticizer described in Patent Document 2 (glycol diester: TEG2EH in Table 2), which is not a cyclic hydrocarbon group-containing dicarboxylic acid ester, exhibited a viscosity of 1.8 Pa·s at 2000 s (Ascending), resulting in insufficient spray coatability.

[0166] Example 15, which used polymer (A-2) having an average of 0.93 dimethoxymethylsilyl groups at one terminal, showed higher tensile properties for the cured product than Example 14, which used polymer (A-1) having an average of 0.83 dimethoxymethylsilyl groups at one terminal. In other words, it can be said that the cured film after coating is more resistant to impact and abrasion.

[0167]

[0168] As can be seen from Table 3, Reference Examples 8 to 12, which used polymer (A-2) having an average of 0.93 dimethoxymethylsilyl groups at one end, exhibited higher tensile properties for the cured products than Reference Examples 3 to 7, which used polymer (A-1) having an average of 0.83 dimethoxymethylsilyl groups at one end. In other words, it can be said that the cured films after coating are more resistant to impact and abrasion.

[0169] (Examples 16 to 20) According to the compositions (weight ratios) shown in Table 4, polymer (A-1) was first mixed with a plasticizer, a diluent, a filler (calcium carbonate and titanium oxide), a rheology modifier, an ultraviolet absorber, and a light stabilizer, and the mixture was stirred using a planetary centrifugal stirring / degassing mixer (manufactured by Samsung Industries Co., Ltd., product name: Hi-Rotor HR005-04V). After cooling the mixture to 50°C or below, A-171 (manufactured by Momentive Performance Materials Holdings Inc.: vinyltrimethoxysilane) as a dehydrating agent, A-1120 (manufactured by Momentive Performance Materials Holdings Inc.: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane) as an adhesion promoter, and Neostan U-220H (manufactured by Nitto Kasei Co., Ltd.: dibutyltin bisacetylacetonate) as a curing catalyst were sequentially added thereto, and the mixture was thoroughly mixed with a spatula. After that, the mixture was stirred and degassed using a planetary centrifugal stirring and degassing mixer to obtain a curable composition. When preparing the curable composition subjected to the spray coatability test, stirring was carried out using a 50 L twin-screw mixer (manufactured by Inoue Seisakusho).

[0170] (Spray Coatability Test) The resulting curable compositions were evaluated for spray coatability at a spray pressure of 16 to 17 MPa using a Graco Mark V electric airless sprayer equipped with a #523 or #531 spray tip. The hose length was 30 m. The coated surface was sprayed once horizontally over a distance of approximately 110 cm, with the distance between the coated surface and the spray nozzle maintained at approximately 50 cm. The presence or absence of coating unevenness and the maximum and minimum film thicknesses were evaluated on the coated surface. Furthermore, spray coating was continued until a predetermined film thickness was achieved, and the film thickness at which dripping began to occur was measured. The results are shown in Table 4.

[0171]

[0172] Examples 16 to 20 in Table 4 show that by blending 0.6 parts by weight or more of a polyamide rheology modifier (D) with 100 parts by weight of a reactive silicon group-containing polyoxyalkylene polymer (A), in addition to a hydrocarbon diluent (B) and a cyclic hydrocarbon group-containing dicarboxylic acid ester plasticizer (C), it is possible to achieve both spray coatability and resistance to sagging after coating. On the other hand, a comparative example (not shown in the table) in which the amount of polyamide rheology modifier (D) was reduced to 0.5 parts by weight was found in preliminary tests to be prone to sagging after coating. Therefore, a spray coatability evaluation test was not conducted for this case.

Claims

1. A curable composition for spray coating, comprising 100 parts by weight of a polyoxyalkylene polymer (A) having a reactive silicon group, 10 to 50 parts by weight of a hydrocarbon diluent (B), 30 to 90 parts by weight of a plasticizer (C) which is a dicarboxylic acid ester containing a cyclic hydrocarbon group, and 0.6 to 7 parts by weight of a polyamide-based rheology modifier (D).

2. The curable composition according to claim 1, wherein the hydrocarbon diluent (B) contains at least one selected from the group consisting of naphthenic diluents and paraffinic diluents.

3. The curable composition according to claim 1 or 2, wherein the boiling point of the hydrocarbon diluent (B) is 250 °C or higher.

4. The curable composition according to claim 1 or 2, further containing a filler (E), wherein the content of the filler (E) is 20 to 40% by weight based on 100% by weight of the total amount of the curable composition.

5. The curable composition according to claim 4, wherein the filler (E) contains calcium carbonate.

6. The curable composition according to claim 5, wherein the calcium carbonate is surface-treated heavy calcium carbonate.

7. The curable composition according to claim 1 or 2, wherein the ratio of the plasticizer (C) to the hydrocarbon diluent (B): (C) / (B) is 0.8 to 3.0 on a weight basis.

8. The curable composition according to claim 1 or 2, wherein the ratio of the total of the polyoxyalkylene polymer (A) and the plasticizer (C) to the hydrocarbon diluent (B): [(A)+(C)] / (B) is 2.6 to 7.0 on a weight basis.

9. The curable composition according to claim 1 or 2, wherein the average number of reactive silicon groups per terminal of the polyoxyalkylene polymer (A) is 0.85 or more.

10. The curable composition according to claim 1 or 2, wherein the viscosity of the curable composition measured at a temperature of 23 °C and a shear rate of 2 / sec is 4 Pa·s or more.

11. The curable composition according to claim 1 or 2, wherein the viscosity of the curable composition measured at a temperature of 23 °C and a shear rate of 2000 / sec is 1.5 Pa·s or less.

12. A cured film obtained by spray-coating and curing the curable composition according to claim 1 or 2.

13. A method for producing a cured film, comprising spray-coating the curable composition according to claim 1 or 2 on a substrate surface and then curing it.

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