Hydroxyl group-containing organopolysiloxane, method for producing same, curable composition containing said organopolysiloxane, coating agent, and coated article

Abstract

Provided is a hydroxyl group-containing organopolysiloxane represented by formula (I). (R1 is a monovalent saturated hydrocarbon group or the like, R2 is a methyl group or the like, R3 and R4 are monovalent saturated hydrocarbon groups or the like, R5 is a monovalent saturated hydrocarbon group or the like, R6 is a hydrogen atom or the like, X1 and X2 are divalent hydrocarbon groups, a to d are numbers that satisfy the relationships 0≤a<1, 0<b≤1, 0≤c≤0.5, 0≤d<1 and a+b+c+d=1, e to h are numbers that satisfy the relationships 0≤e≤1, 0≤f<1, 0≤g<1, 0<h<4, 0<f+g<1 and 0<e+2f+g+h<4, k and m are numbers between 0 and 1000, and n is a number between 0 and 400)

Description

Hydroxyl-containing organopolysiloxane, its production method, curable composition containing said organopolysiloxane, coating agent, and coated article

[0001] The present invention relates to a hydroxyl-containing organopolysiloxane, a method for producing the same, and a curable composition, coating agent, and coated article containing the organopolysiloxane.

[0002] Organopolysiloxanes containing alkoxysilyl groups are widely used in paints and coatings. Generally, organopolysiloxanes with terminal alkoxy groups are formulated with a curing catalyst, and when external energy such as heat energy is applied, the terminal alkoxy groups react with each other to form a strong siloxane network. The resulting coatings have excellent heat resistance, chemical resistance, stain resistance, and weather resistance, making them suitable for a wide range of applications, from outdoor structures to automotive parts and electronic components.

[0003] On the other hand, although organopolysiloxane-based paints have the above advantages, they have the drawbacks of being slow in curing and of the resulting coating films being poor in crack resistance and flex resistance.

[0004] To overcome these drawbacks, a known technique is to use a composition obtained by combining an organopolysiloxane with an organic resin such as an alkyd resin, a polyester resin, or an acrylic resin as a coating material (see Patent Documents 1 to 3). However, although these compositions improve curability and crack resistance, they may reduce the chemical resistance, stain resistance, weather resistance, and other properties that are characteristic of organopolysiloxane-based resin coating films.

[0005] The most common functional group in organic resins is the hydroxyl group, which is a common functional group in the alkyd resins, polyester resins, and acrylic resins, and there are many polyol resins on the market that contain hydroxyl groups.

[0006] On the other hand, while linear polydimethylsiloxanes with both ends modified with carbinol are known as hydroxyl group-containing organopolysiloxanes, they have poor curability and are currently almost nonexistent on the market as hydroxyl group-containing organopolysiloxanes capable of forming a strong siloxane network. While the alkoxysilanes contained in general organopolysiloxanes undergo hydrolysis in the presence of water, a similar reaction also occurs with hydroxyl groups. Therefore, hydroxyl group-containing organopolysiloxanes have the disadvantage of being difficult to sell due to concerns about their stability over time.

[0007] Against this background, Non-Patent Documents 1 and 2 propose a method for synthesizing hydroxyl-containing organopolysiloxanes by forming an organopolysiloxane into a cage structure, thereby eliminating alkoxysilanes in the molecule. However, this method requires the reaction to be carried out under sufficiently diluted conditions in order to form the organopolysiloxane into a cage structure, resulting in low yields and making industrialization difficult.

[0008] JP-A-11-116683 JP-A-5-345877 Patent No. 5384939

[0009] H. Mori, et al., Langmuir, 2007, 23, 17, 9014-9023H. Takeuchi, et al., Reactive and Functional Polymers, 2017, 115, 43-52

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydroxyl group-containing organopolysiloxane that, when used in a curable composition, has excellent curability and provides a coating film with excellent antifouling properties.

[0011]

[0005] As a result of extensive research to achieve the above object, the present inventors have found that a hydroxyl-containing organopolysiloxane represented by the following formula (I) has excellent curability when used in a curable composition and gives a coating film with excellent antifouling properties, and that the above hydroxyl-containing organopolysiloxane can be obtained under specified conditions, thereby completing the present invention.

[0012] That is, the present invention provides: 1. a hydroxyl group-containing organopolysiloxane represented by the following formula (I): (In the formula, R 1 are each independently a hydrogen atom, or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom; R 2 is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and R 3 and R 4 are each independently a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom; R 5 represents a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms, which may be substituted with a halogen atom; R 6 are each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 8 carbon atoms, and X 1 and X 2 are each independently a divalent hydrocarbon group having 2 to 12 carbon atoms, a, b, c, and d are each numbers that satisfy 0≦a<1, 0<b≦1, 0≦c≦0.5, 0≦d<1, and a+b+c+d=1, e, f, g, and h are each numbers that satisfy 0≦e≦1, 0≦f<1, 0≦g<1, 0<h<4, and 0<f+g<1, 0<e+2f+g+h<4, k and m are numbers from 0 to 1000, and n is a number from 0 to 400.) 2. In the formula (I), R 1 3. The hydroxyl group-containing organopolysiloxane according to 1, wherein each of R is independently a methyl group or a phenyl group; 2is a hydrogen atom or a methyl group, 4. A hydroxyl-containing organopolysiloxane according to any one of 1 to 3, wherein in formula (I), b is a number satisfying 0.5≦b≦1, 5. A hydroxyl-containing organopolysiloxane according to any one of 1 to 4, wherein in formula (I), a and d are 0, 6. A hydroxyl-containing organopolysiloxane according to formula (I), wherein R 3 7. The hydroxyl group-containing organopolysiloxane according to any one of 1 to 5, wherein R is a methyl group; 4 is a methyl group, and R 5 is a methyl group or a vinyl group, and X 1 7. The hydroxyl group-containing organopolysiloxane according to any one of 1 to 6, wherein R is an ethylene group, and k and m are numbers from 5 to 150. 6 is a hydrogen atom, and X 2 8. The hydroxyl-containing organopolysiloxane according to any one of 1 to 7, wherein n is an alkylene group having 3 carbon atoms and n is 1, 9. The hydroxyl-containing organopolysiloxane according to any one of 1 to 8, wherein the weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography is 1,000 to 500,000, 10. (Step α): A step of obtaining an organopolysiloxane having SiH groups by a hydrolysis condensation reaction between an organopolysiloxane represented by the following formula (II) and a silane compound represented by the following formula (III), or by an equilibration reaction between an organopolysiloxane represented by the following formula (II) and a disiloxane compound represented by the following formula (IV) using an acid catalyst, (In the formula, R 1 , R 2 , a, b, c, and d are the same as above, and i is a number satisfying 0<i<4.) (In the formula, R 3 is the same as above, and R 7is a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 4 carbon atoms.) (Step β): A step of subjecting the organopolysiloxane having SiH groups obtained in the above (Step α) to a hydrosilylation reaction with a compound represented by the following formula (V), a compound represented by the following formula (VI), or both of them, and a compound represented by the following formula (VII): (In the formula, R 4 , R 5 , R 6 , m and n are the same as above, and R 8 and R 9 is a monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms, and p is a number from 0 to 1,000.), 11. a curable composition comprising the hydroxyl-containing organopolysiloxane of any one of 1 to 9 and a curing agent capable of reacting with hydroxyl groups, 12. a coating agent comprising the curable composition of 11, 13. a cured film formed from the curable composition of 11, and 14. a coated article having a substrate and the cured film of 13 formed on at least one surface of the substrate directly or via one or more other layers.

[0013] The hydroxyl-containing organopolysiloxane of the present invention cures rapidly when mixed with a curing agent and applied, and the resulting cured film has excellent chemical resistance and stain resistance, making it suitable for producing a variety of coated articles.

[0014] The present invention will now be described in detail. (1) Hydroxyl-containing organopolysiloxane The hydroxyl-containing organopolysiloxane of the present invention has a ratio of constituent units represented by the following formula (I).

[0015]

[0016] In formula (I), R 1 are each independently a hydrogen atom, or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom.

[0017] R 1The monovalent saturated hydrocarbon group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, neopentyl, n-hexyl, n-heptyl, and n-octyl groups; and cycloalkyl groups such as cyclopentyl and cyclohexyl groups. Of these, alkyl groups having 1 to 6 carbon atoms are preferred, and alkyl groups having 1 to 3 carbon atoms are more preferred, with methyl and ethyl being even more preferred. As aralkyl groups having 7 to 20 carbon atoms, those having 7 to 10 carbon atoms are preferred, and specific examples thereof include benzyl and phenylethyl groups. The aryl group having 6 to 18 carbon atoms is preferably one having 6 to 10 carbon atoms, and specific examples thereof include unsubstituted aryl groups such as phenyl and naphthyl groups; and alkylaryl groups such as tolyl, xylyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, and dodecylphenyl groups, with a phenyl group being preferred. 1 is preferably a methyl group or a phenyl group. In addition, the monovalent saturated hydrocarbon group, aralkyl group and aryl group, some or all of the hydrogen atoms may be substituted with halogen atoms (fluorine, chlorine, bromine, iodine atoms), and specific examples thereof include chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, chlorophenyl, and bromophenyl groups. Furthermore, R 1 At least one of the groups is preferably a halogen-substituted or unsubstituted aryl group having 6 to 18 carbon atoms.

[0018] R 2 represents a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, preferably a hydrogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a methyl group.

[0019] R 3 and R 4are each independently a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, which may be substituted with a halogen atom, and specific examples thereof include the above-mentioned R 1 Among these, R 3 and R 4 is preferably a methyl group.

[0020] R 5 is a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms, which may be substituted with a halogen atom, and specific examples thereof include the above-mentioned R 1 In addition to the groups exemplified by R, examples of the monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms include alkenyl groups such as vinyl, allyl, 3-butenyl, 5-hexenyl, and 7-octenyl, with vinyl and allyl groups being preferred, and vinyl being more preferred. 5 is preferably a methyl group or a vinyl group.

[0021] R 6 are each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 8 carbon atoms, and R 6 The monovalent saturated hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include R 1 Among the groups exemplified in , those having 1 to 8 carbon atoms can be mentioned. 6 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom.

[0022] X 1 and X 2 are each independently a divalent hydrocarbon group having 2 to 12 carbon atoms, preferably a linear or branched divalent aliphatic hydrocarbon group, specific examples of which include alkylene groups such as ethylene, trimethylene, propylene, tetramethylene, hexamethylene, and octamethylene, and arylene groups such as phenylene, with alkylene groups having 2 or 3 carbon atoms being preferred.1 is preferably an ethylene group, and X 2 is preferably an alkylene group having 3 carbon atoms, more preferably a trimethylene group.

[0023] In formula (I), a is a number that satisfies 0≦a<1, but from the viewpoint of crack suppression effect, a number that satisfies 0≦a≦0.3 is preferred, and a=0 is more preferred. b is a number that satisfies 0<b≦1, but from the viewpoint of the scratch resistance of the resulting cured product, a number that satisfies 0.5≦b≦1 is preferred, and a number that satisfies 0.6≦b≦1 is more preferred. c is a number that satisfies 0≦c≦0.5, but from the viewpoint of the curability of the composition and the hardness of the resulting cured product, a number that satisfies 0≦c≦0.4 is preferred. d is a number that satisfies 0≦d<1, but from the viewpoint of the curability of the composition and the hardness of the resulting cured product, a number that satisfies 0≦d≦0.2 is preferred, and d=0 is more preferred. Note that a, b, c, and d are numbers that satisfy a+b+c+d=1.

[0024] e is a number that satisfies 0≦e≦1, but from the viewpoint of suppressing the condensation reaction by the condensable functional group, a number that satisfies 0≦e≦0.8 is preferred, and a number that satisfies 0≦e≦0.5 is more preferred. f is a number that satisfies 0≦f<1, but from the viewpoint of the hardness of the obtained cured product, a number that satisfies 0≦f<0.5 is preferred, a number that satisfies 0≦f≦0.2 is more preferred, and a number that satisfies 0≦f≦0.1 is even more preferred. g is a number that satisfies 0≦g<1, but from the viewpoint of the hardness of the obtained cured product, a number that satisfies 0≦g<0.5 is preferred, a number that satisfies 0≦g≦0.2 is more preferred, and a number that satisfies 0≦g≦0.1 is even more preferred. h is a number that satisfies 0<h<4, but from the viewpoint of the crosslink density of the cured product, a number that satisfies 0.1<h≦2 is preferred, and a number that satisfies 0.1<h≦1 is even more preferred. Note that e, f, g, and h are numbers that satisfy 0<f+g<1 and 0<e+2f+g+h<4, preferably numbers that satisfy 0<f+g≦0.4 and 0.2<e+2f+g+h≦1.2, and more preferably numbers that satisfy 0<f+g≦0.1 and 0.2<e+2f+g+h≦1.2.

[0025] k and m are numbers from 0 to 1000, but from the viewpoints of compatibility with the curing agent and the stain resistance of the resulting cured product, they are preferably numbers from 5 to 500, more preferably numbers from 5 to 300, and even more preferably numbers from 5 to 150. n is a number from 0 to 400, but from the viewpoint of solubility, it is preferably a number from 0 to 100, more preferably 0 or 1, and even more preferably 1.

[0026] The hydroxyl group-containing organopolysiloxane of the present invention is a hydroxyl group-containing organopolysiloxane represented by the formula (I) above, wherein R 1 are each independently a methyl group or a phenyl group, R 2 , R 3 and R 4 is a methyl group, R 5 is a methyl group or a vinyl group, R 6 is a hydrogen atom, X 1 is an ethylene group, X 2 is an alkylene group having 3 carbon atoms, a is 0, b is a number satisfying 0.5≦b≦1, c is a number satisfying 0≦c≦0.5, d is 0 and a number satisfying a+b+c+d=1, e is a number satisfying 0≦e≦0.8, f is a number satisfying 0≦f≦0.2, g is a number satisfying 0≦g≦0.2, h is a number satisfying 0.1<h≦2 and is a number satisfying 0<f+g≦0.4 and 0.2<e+2f+g+h≦1.2, k and m are numbers from 5 to 150, and n is 1.

[0027] The weight average molecular weight (Mw) of the hydroxyl group-containing organopolysiloxane of the present invention, measured by gel permeation chromatography (GPC) in terms of polystyrene, is preferably 1,000 to 500,000, more preferably 1,000 to 50,000, and even more preferably 1,500 to 10,000. A weight average molecular weight of 1,000 or more will provide superior storage stability and flex resistance, while a weight average molecular weight of 500,000 or less will eliminate the risk of unevenness or coating irregularities during coating. The GPC measurement conditions can be, for example, the methods used in the Examples below.

[0028] The amount of hydroxyl groups contained in the hydroxyl-containing organopolysiloxane of the present invention is not particularly limited, but the hydroxyl value is preferably 20 to 200 mgKOH / g, and more preferably 40 to 180 mgKOH / g. Note that, in the present invention, the hydroxyl value is a value according to JIS K 0070:1992.

[0029] The hydroxyl-containing organopolysiloxane of the present invention may be of a single composition or a mixture of multiple compounds with different compositions.

[0030] (2) Method for Producing Hydroxyl-Containing Organopolysiloxane The method for producing the hydroxyl-containing organopolysiloxane of the present invention is not particularly limited, and it can be obtained, for example, by a production method including the following steps (α) and (β): (Step α): A step of obtaining an organopolysiloxane having SiH groups by a hydrolysis condensation reaction between an organopolysiloxane represented by the following formula (II) and a silane compound represented by the following formula (III), or by an equilibration reaction using an acid catalyst between an organopolysiloxane represented by the following formula (II) and a disiloxane compound represented by the following formula (IV): (In the formula, R 1 , R 2 , a, b, c, and d are the same as above, and i is a number satisfying 0<i<4.) (In the formula, R 3 is the same as above, and R 7 is a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 4 carbon atoms.) (Step β): A step of subjecting the organopolysiloxane having SiH groups obtained in the above (Step α) to a hydrosilylation reaction with a compound represented by the following formula (V), a compound represented by the following formula (VI), or both of them, and a compound represented by the following formula (VII): (In the formula, R 4 , R 5 , R 6 , m and n are the same as above, and R 8 and R 9 is a monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms, and p is a number from 0 to 1000.

[0031] <(Step α)> (Step α) is a step of obtaining an organopolysiloxane having SiH groups by a hydrolysis condensation reaction between an organopolysiloxane represented by formula (II) above and a silane compound represented by formula (III) above, or by an equilibration reaction between an organopolysiloxane represented by formula (II) above and a disiloxane compound represented by formula (IV) above using an acid catalyst.

[0032] In formula (II), i is a number that satisfies 0<i<4, and preferably a number that satisfies 0.2<i≦2.8.

[0033] The organopolysiloxane represented by formula (II) is preferably R 1 are each independently a methyl group or a phenyl group, R 2 is a methyl group, a is 0, b is a number satisfying 0.5≦b≦1, c is a number satisfying 0≦c≦0.5, d is 0 and a number satisfying a+b+c+d=1, and i is a number satisfying 0.2<i≦2.8.

[0034] The organopolysiloxane represented by formula (II) can be produced by a general method for producing organopolysiloxanes, for example, by hydrolytic condensation of a silane compound having a hydrolyzable group.

[0035] The silane compound having a hydrolyzable group is not particularly limited as long as it contains 1 to 4 hydrolyzable groups, chloro groups or alkoxy groups, on the silicon atom and has an organic substituent that satisfies the above conditions. Specific examples thereof include tetrachlorosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiisopropoxysilane, trimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, ethyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrichlorosilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrichlorosilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrichlorosilane, hexyltrimethoxysilane, hexyltriethoxysilane, and phenyltrichlorosilane. , phenyltrimethoxysilane, phenyltriethoxysilane, cyclohexyltrichlorosilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, propylmethyldichlorosilane, propylmethyldimethoxysilane, propylmethyldiethoxysilane, hexylmethyldichlorosilane, hexylmethyldimethoxysilane, hexylmethyldiethoxysilane, phenylmethyldichlorosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, diphenyldichlorosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, dimethylphenylchlorosilane, dimethylphenylmethoxysilane, dimethylphenylethoxysilane, and partial hydrolysates thereof are examples of such silane compounds. However, in view of operability, ease of distilling off by-products, and ease of raw material availability, silanes containing 1 to 4 methoxy or ethoxy groups on the silicon atom are preferred. The above silane compounds may be used alone or in combination of two or more.

[0036] A hydrolysis catalyst may be used when carrying out hydrolysis. Conventionally known catalysts can be used as the hydrolysis catalyst, and those whose aqueous solutions exhibit an acidic pH of 2 to 7 (acidic catalysts) are preferred, with acidic hydrogen halides, sulfonic acids, carboxylic acids, acidic or weakly acidic inorganic salts, and solid acids such as ion exchange resins being particularly preferred. Specific examples of acidic catalysts include hydrogen fluoride, hydrochloric acid, nitric acid, sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, formic acid, acetic acid, maleic acid, benzoic acid, lactic acid, phosphoric acid, and cation exchange resins having sulfonic acid or carboxylic acid groups on their surfaces.

[0037] The amount of the hydrolysis catalyst used is not particularly limited, but in order to ensure that the reaction proceeds quickly and to facilitate easy removal of the catalyst after the reaction, it is preferable to use 0.0002 to 0.5 moles per mole of hydrolyzable silane.

[0038] The mass ratio of the silane compound having a hydrolyzable group to the water required for the hydrolysis condensation reaction is not particularly limited, but in order to prevent deactivation of the catalyst and allow the reaction to proceed sufficiently, and in consideration of ease of removal of water after the reaction, a ratio of 0.1 to 10 moles of water per mole of hydrolyzable silane is preferred. The reaction temperature during the hydrolysis condensation is not particularly limited, but in consideration of improving the reaction rate and preventing decomposition of the organic functional group, -10 to 150°C is preferred. The reaction time is not particularly limited, but 0.5 to 6 hours is preferred.

[0039] An organic solvent may be used during the hydrolysis and condensation. Specific examples of the organic solvent that can be used include methanol, ethanol, propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, and xylene.

[0040] In the above formula (III), R 7 Examples of the halogen atom in R include fluorine, chlorine, bromine, and iodine atoms, and examples of the alkoxy group having 1 to 4 carbon atoms include methoxy, ethoxy, n-propoxy, and n-butoxy groups. 7 is preferably a chlorine atom, a hydroxyl group, a methoxy group or an ethoxy group.

[0041] Specific examples of the silane compound represented by the formula (III) include dimethylmethoxysilane, dimethylethoxysilane, dimethylchlorosilane, and dimethylhydroxysilane.

[0042] Specific examples of disiloxane compounds represented by the formula (IV) include 1,1,3,3-tetramethyldisiloxane.

[0043] In the step of obtaining an organopolysiloxane having SiH groups by the hydrolysis and condensation reaction of an organopolysiloxane represented by formula (II) and a silane compound represented by formula (III), the conditions for the hydrolysis and condensation reaction are not particularly limited, but can be carried out under the same conditions as those for producing the organopolysiloxane represented by formula (II). In this case, the ratio of the organopolysiloxane represented by formula (II) to the silane compound represented by formula (III) is not particularly limited, but preferably 5 to 80 parts by mass, more preferably 10 to 70 parts by mass, of the silane compound represented by formula (III) per 100 parts by mass of the organopolysiloxane represented by formula (II). When a hydrolysis catalyst is used, the amount used is not particularly limited, but preferably 0.0002 to 0.5 moles per mole of the silane compound represented by formula (III).

[0044] The mass ratio of the hydrolyzable groups contained in the organopolysiloxane represented by formula (II) to the water required for the hydrolysis-condensation reaction is not particularly limited, but because the reaction rate can be changed by the amount of water added, a mass ratio appropriate for the desired reaction rate is preferred. From the perspective of ensuring storage stability by reducing the number of highly active silanol groups and / or alkoxy groups at the organopolysiloxane terminals, the reaction rate of the silanol groups and / or alkoxy groups is preferably 50 to 100 mol%, and more preferably 60 to 100 mol%.

[0045] On the other hand, in the step of obtaining an organopolysiloxane having SiH groups by an equilibration reaction (siloxane bond cleavage / recombination reaction) between an organopolysiloxane represented by formula (II) above and a disiloxane compound represented by formula (IV) above using an acid catalyst, the equilibration reaction conditions are not particularly limited, but can be carried out, for example, at 20 to 150°C for about 0.5 to 6 hours, preferably at 20 to 100°C for about 1 to 4 hours. In this case, a solvent may be added as needed. Examples of the solvent include alcohol solvents such as methanol, ethanol, and isopropyl alcohol; and aromatic nonpolar solvents such as benzene, toluene, and xylene.

[0046] The proportions of the organopolysiloxane represented by formula (II) above and the disiloxane compound represented by formula (IV) above used are not particularly limited, but the proportion of the disiloxane compound represented by formula (IV) above is preferably 10 to 70 parts by mass, and more preferably 20 to 60 parts by mass, per 100 parts by mass of the organopolysiloxane represented by formula (II) above.

[0047] The acidic catalyst for promoting the equilibration reaction is preferably a strong acid, and although any type is not particularly important, sulfuric acid, methanesulfonic acid, trifluoromethanesulfonic acid, etc. are preferably used, and cation exchange resins having these exchange groups are particularly preferred because of the ease of post-treatment. The amount of acidic catalyst added is preferably 100 to 10,000 ppm, and more preferably 500 to 3,000 ppm, based on the total mass of the organopolysiloxane represented by formula (II) above and the disiloxane compound represented by formula (IV) above.

[0048] During the equilibration reaction, water may be added to promote the hydrolysis and condensation reaction between the organopolysiloxane represented by formula (II) and the disiloxane compound represented by formula (IV). The amount of water used is not particularly limited, but because the reaction rate can be changed by adjusting the amount of water added, a mass ratio appropriate for the desired reaction rate is preferred. From the perspective of ensuring storage stability by reducing the number of highly active silanol or alkoxy groups at the terminals of the organopolysiloxane, the reaction rate of the silanol or alkoxy groups is preferably 50 to 100 mol%, and more preferably 60 to 100 mol%.

[0049] <(Step β)> (Step β) is a step of subjecting the organopolysiloxane having SiH groups obtained in (Step α) above to a hydrosilylation reaction with the compound represented by formula (V) above, the compound represented by formula (VI) above, or both, and the compound represented by formula (VII) above.

[0050] In the above formulas (V), (VI) and (VII), R 8 and R 9 Examples of the monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms include alkenyl groups such as vinyl, allyl, 3-butenyl, 5-hexenyl, and 7-octenyl groups, and alkenyl groups having 2 to 6 carbon atoms are preferred, with vinyl and allyl groups being more preferred. 8 is preferably a vinyl group, and R 9 is preferably an allyl group.

[0051] In the above formula (V), p is a number from 0 to 1,000, but from the viewpoints of compatibility with the curing agent of the resulting hydroxyl group-containing organopolysiloxane and the stain resistance of the resulting cured product, it is preferably a number from 5 to 500, more preferably 5 to 300, and even more preferably 5 to 150.

[0052] The compound represented by formula (V) above is preferably a dimethylpolysiloxane in which both molecular chain terminals are blocked with dimethylvinylsiloxy groups, and the compound represented by formula (VI) above is preferably a dimethylpolysiloxane in which one molecular chain terminal is blocked with a trimethylsiloxy group and the other molecular chain terminal is blocked with a dimethylvinylsiloxy group.

[0053] As the compound represented by the above formula (VII), vinyl alcohol, allyl alcohol, and ethylene glycol monoallyl ether are preferred, and ethylene glycol monoallyl ether is more preferred, taking into consideration compatibility with organopolysiloxane.

[0054] The compounds represented by formulas (V), (VI), and (VII) are preferably used in the hydrosilylation reaction in such amounts that the total amount of monovalent aliphatic unsaturated hydrocarbon groups is 1 mole or more per mole of SiH groups in the SiH group-containing organopolysiloxane obtained in (Step α). The ratio of the total number of moles of the compounds represented by formulas (V) and (VI):the number of moles of the compound represented by formula (VII) is preferably 1:99 to 20:80.

[0055] The hydrosilylation reaction is preferably carried out in the presence of a catalyst. Examples of the hydrosilylation catalyst that can be used include compounds containing platinum group metals such as platinum, rhodium, and palladium. Among these, platinum-containing compounds are preferred, such as platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of chloroplatinic acid with olefins, vinylsiloxanes, acetylene alcohols, and the like, platinum carbonylvinylmethyl complexes, platinum-divinyltetramethyldisiloxane complexes, platinum-cyclovinylmethylsiloxane complexes, and platinum-octylaldehyde / octanol complexes. When a hydrosilylation catalyst is used, its amount may be a catalytic amount that can promote the addition reaction, and is typically 0.1 to 500 ppm, preferably 1 to 200 ppm, of the platinum group metal relative to the total mass of the compound represented by formula (V), the compound represented by formula (VI), or both, and the compound represented by formula (VII).

[0056] The hydrosilylation reaction proceeds without a solvent, but can also be carried out in the presence of a solvent. Specific examples of the solvent include hydrocarbon solvents such as pentane, hexane, cyclohexane, heptane, isooctane, benzene, toluene, and xylene; ether solvents such as diethyl ether, tetrahydrofuran, and dioxane; ester solvents such as ethyl acetate and butyl acetate; aprotic polar solvents such as acetonitrile and N,N-dimethylformamide; and chlorinated hydrocarbon solvents such as dichloromethane and chloroform. These solvents may be used alone or in combination of two or more.

[0057] The conditions for the hydrosilylation reaction are not particularly limited, but a reaction temperature of 20 to 120° C. and a reaction time of 1 to 8 hours are preferred, and a reaction temperature of 20 to 100° C. and a reaction time of 1 to 6 hours are even more preferred. In this way, SiH groups are introduced at the ends of the organopolysiloxane having a hydrolyzable group represented by formula (II) above, and then the resulting organopolysiloxane is subjected to a hydrosilylation reaction with a compound represented by formula (V), a compound represented by formula (VI), or both, and a hydroxyl-containing compound represented by formula (VII), thereby obtaining the hydroxyl-containing organopolysiloxane of the present invention.

[0058] (3) Curable Composition The hydroxyl-containing organopolysiloxane of the present invention can be used as a curable composition by adding a curing agent having a substituent reactive with a hydroxyl group. The curing agent is not particularly limited as long as it is one commonly used in polyol-based paints, but examples include metal driers, polyisocyanates, amino resins such as melamine resins, benzoguanamine resins, urea resins, and thiourea resins, epoxy resins, and polycarboxylic acid anhydrides, with polyisocyanates being preferred. Known polyisocyanates, such as aromatic, aliphatic, araliphatic, and alicyclic polyisocyanates, can be used, but from the perspective of long-term outdoor use, aliphatic polyisocyanates whose main raw material is an aliphatic diisocyanate are preferred.

[0059] Examples of aliphatic diisocyanates include tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter abbreviated as "HDI"), 2,2,4-(or 2,4,4)-trimethyl-1,6-hexamethylene diisocyanate, lysine isocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,4-diisocyanatocyclohexane, 1,3-bis(diisocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, etc. Of these, HDI is particularly suitable from the viewpoints of the crack resistance of the resulting coating film and cost.

[0060] Examples of aliphatic polyisocyanates obtained from aliphatic diisocyanates include allophanate-type polyisocyanates, biuret-type polyisocyanates, adduct-type polyisocyanates, and isocyanurate-type polyisocyanates, and any of these can be suitably used.

[0061] The polyisocyanate may be so-called blocked polyisocyanate, which is blocked with various blocking agents. Examples of blocking agents that can be used include alcohols such as methanol, ethanol, and lactate esters; phenolic hydroxyl group-containing compounds such as phenol and salicylate esters; amides such as ε-caprolactam and 2-pyrrolidone; oximes such as acetone oxime and methyl ethyl ketoxime; and active methylene compounds such as methyl acetoacetate, ethyl acetoacetate, and acetylacetone.

[0062] The amount of curing agent to be blended is not particularly limited, but is preferably an amount such that the ratio of the number of isocyanato groups in the curing agent to the number of hydroxyl groups in the hydroxyl group-containing polysiloxane (NCO / OH) is 0.5 to 1.3, more preferably 0.7 to 1.2. The curing agents may be used alone or in combination of two or more.

[0063] The curable composition of the present invention may further contain a curing catalyst. The curing catalyst is not particularly limited as long as it is one that is commonly used in paints, but is preferably an organometallic compound, such as a metal alkoxide compound of Ti, Al, Zr, Sn, or the like, a metal chelate compound, or a metal ester compound.

[0064] Specific examples of metal alkoxide compounds include aluminum alkoxides such as aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide, aluminum tri-s-butoxide, and aluminum tri-t-butoxide; tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-t-butyl titanate, and tetra-n-hexyl titanate. titanium alkoxides such as tetraethyl zirconate, tetra-n-propyl zirconate, tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-s-butyl zirconate, tetra-t-butyl zirconate, tetra-n-pentyl zirconate, tetra-t-pentyl zirconate, tetra-t-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate, tetra-n-stearyl zirconate, and the like; and dibutyltin dibutoxide.

[0065] Specific examples of metal chelate compounds include tris(ethylacetoacetate)aluminum, tris(n-propylacetoacetate)aluminum, tris(isopropylacetoacetate)aluminum, tris(n-butylacetoacetate)aluminum, isopropoxybis(ethylacetoacetate)aluminum, tris(acetylacetonato)aluminum, tris(propionylacetonato)aluminum, diisopropoxypropionylacetonatoaluminum, acetylacetonatobis(propionylacetonato)aluminum, monoethylacetoacetatebis(acetylacetonato)aluminum, acetylacetonatoaluminumdi-s-butylate, methylacetoacetatealuminumdi-s-butylate, di(methylacetoacetate)aluminummono-tert-butylate, and diisopropoxyethylacetoacetate. Examples of the tin chelate compounds include aluminum, aluminum chelate compounds such as monoacetylacetonato bis(ethylacetoacetate)aluminum; titanium chelate compounds such as diisopropoxy bis(ethylacetoacetate)titanate, diisopropoxy bis(acetylacetonato)titanate, and di-n-butoxy bis(acetylacetonato)titanate; zirconium chelate compounds such as tetrakis(acetylacetonato)zirconium, tetrakis(n-propylacetoacetate)zirconium, and tetrakis(ethylacetoacetate)zirconium; and tin chelate compounds such as tin ester compounds such as dibutyltin diacetate, dibutyltin di(2-ethylhexylate), dibenzyltin di(2-ethylhexylate), dibutyltin dilaurate, dibutyltin diisooctylmaleate, dibutyltin bis(acetylacetonate), and dioctyltin dilaurate.

[0066] As the tin ester compound, commercially available products may be used, and examples thereof include Neostan U-100, U-130, U-200, U-220H, U-303, U-700, U-810, U-820, and U-830 (all manufactured by Nitto Kasei Co., Ltd.), and BT-120S (manufactured by Kaneka Corporation).

[0067] When a curing catalyst is added, the amount added should be sufficient to cure the composition, but is preferably 0.0001 to 20 parts by mass, and more preferably 0.001 to 5 parts by mass, per 100 parts by mass of the nonvolatile content of the hydroxyl group-containing organopolysiloxane. The curing catalyst may be used alone or in combination of two or more types.

[0068] The curable composition of the present invention may contain any additives as appropriate, as long as they do not impair the effects of the present invention. Specific examples of additives include solvents, adhesion promoters such as silane coupling agents, non-reactive polymer resins, fillers, leveling agents, rheology modifiers, reactive diluents, non-reactive diluents, surfactants, dispersants, antifoaming agents, dehydrating agents, antioxidants, antioxidants, antistatic agents, infrared absorbers, ultraviolet absorbers, light stabilizers, fluorescent agents, dyes, pigments, fragrances, abrasives, rust inhibitors, and thixotropy-imparting agents. These may be used alone or in combination of two or more.

[0069] The curable composition of the present invention may contain a hydroxyl group-containing compound other than the hydroxyl group-containing organopolysiloxane. Specific examples of such curable compositions include, but are not limited to, polyester- or alkyd-based curable compositions containing the hydroxyl group-containing organopolysiloxane of the present invention, a polyol, and a polybasic acid; polyurethane-based curable compositions containing the hydroxyl group-containing organopolysiloxane of the present invention, a polyol, and a polyisocyanate; epoxy-based curable compositions containing the hydroxyl group-containing organopolysiloxane of the present invention, a polyol, and an epoxy resin; and curable compositions containing the hydroxyl group-containing organopolysiloxane of the present invention, a polyol, an etherified melamine resin, and / or a benzoguanamine resin.

[0070] Furthermore, the reaction product of the hydroxyl-containing organopolysiloxane of the present invention with a compound having a substituent reactive with a hydroxyl group and a radically polymerizable group can be used as a photocurable composition or a thermosetting composition by adding a photoradical polymerization initiator or a thermosetting radical polymerization initiator. Specific examples of such curable compositions include a photocurable composition containing a reaction product of the hydroxyl-containing organopolysiloxane of the present invention with an isocyanato group-containing (poly)acrylate and a photoradical polymerization initiator.

[0071] The curable composition of the present invention can be obtained by mixing and stirring the hydroxyl-containing organopolysiloxane, the curing agent, and optionally the curing catalyst and other components in any order. There are no particular limitations on the mixing conditions, but in consideration of workability and composition stability, mixing is preferably carried out at 10 to 40°C.

[0072] (4) Cured film of curable composition and coated article The curable composition of the present invention can be suitably used as a coating agent, particularly as an exterior wall paint, but its application is not particularly limited. When used as a coating agent, for example, the curable composition of the present invention can be applied to at least one surface of a substrate directly or via one or more other layers, and then cured to form a coating, thereby obtaining a coated article having a cured film of the curable composition formed directly or via one or more other layers on at least one surface of the substrate.

[0073] The substrate may include, but is not limited to, glass, silicon wafers, metals, plastic molded bodies, ceramics, composites thereof, etc. Substrates whose surfaces have been treated with chemical conversion coating, corona discharge treatment, plasma treatment, or acid or alkali solution, as well as decorative plywood whose surface layer is coated with a different type of paint from the substrate itself, can also be used. Examples of other layers include those obtained by polyester resin coating, polyurethane resin coating, aminoalkyd resin coating, lacquer coating, spray coating, and aqueous wax coating.

[0074] The method for applying the curable composition of the present invention to a substrate may be appropriately selected from known techniques, and various application methods can be used, for example, roll coating, bar coating, wire bar coating, spray coating, flow coating, spin coating, curtain coating, knife coating, dip coating, brush coating, etc. The amount to be applied is not particularly limited, but usually, an amount that results in a coating thickness of 0.1 to 1,000 μm after drying is preferred, and an amount that results in a coating thickness of 1 to 100 μm is more preferred.

[0075] Methods for curing the composition include room temperature curing and heat curing. The composition of the present invention can be cured at room temperature (for example, 5 to 35°C), but may be heated as needed to accelerate curing. When heated, the heating temperature is not particularly limited, but is preferably 50 to 200°C, and more preferably 80 to 150°C.

[0076] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The average composition of organopolysiloxane was measured using an NMR measurement device manufactured by JEOL Ltd. 1 H-NMR and 29 The hydroxyl value is a value measured by neutralization titration in accordance with JIS K 0070:1992, and the weight average molecular weight (Mw) is a polystyrene-equivalent value determined by GPC (gel permeation chromatography) measurement under the following conditions. [GPC conditions] Apparatus: HLC-8220 (manufactured by Tosoh Corporation) Columns: TSKgel GMHXL-L, TSKgel G4000HXL, TSKgel G2000HXL x 2 Developing solvent: tetrahydrofuran (THF) Flow rate: 1 mL / min Detector: RI Column thermostat temperature: 40°C Standard: polystyrene

[0077] [1] Synthesis of hydroxyl group-containing organopolysiloxanes The organopolysiloxanes of Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4 were produced using the following organopolysiloxanes R-A to R-D and O-A to O-E as raw materials. <Raw material organopolysiloxanes> R-A: In the above formula (II), a = 0, b = 0.6, c = 0.4, d = 0, i = 1.1, R 1: methyl group, phenyl group, R 2 : Organopolysiloxane resin (weight average molecular weight 1,500) represented by a methyl group. R-B: In the above formula (II), a = 0, b = 0.9, c = 0.1, d = 0, i = 1.3, R 1 : methyl group, phenyl group, R 2 : Organopolysiloxane resin (weight average molecular weight 1,800) represented by a methyl group. R-C: In the above formula (II), a = 0, b = 1, c = 0, d = 0, i = 0.8, R 1 : methyl group, R 2 : Organopolysiloxane resin (weight average molecular weight 1,500) represented by a methyl group. RD: In the above formula (II), a = 0, b = 0.6, c = 0.4, d = 0, i = 0.2, R 1 : methyl group, phenyl group, R 2 : organopolysiloxane resin (weight average molecular weight 10,000) represented by a hydrogen atom. OA: R in the above formula (V). 4 : methyl group, R 8 OB: a linear organopolysiloxane having a vinyl group and p=10; 4 : methyl group, R 8 : a linear organopolysiloxane having a vinyl group and p=43; O-C: R in the above formula (V); 4 : methyl group, R 8 : a linear organopolysiloxane having a vinyl group and p=68; OD: a group represented by the formula (V) above where R 4 : methyl group, R 8 : a linear organopolysiloxane having a vinyl group and p=146; O-E: a group represented by the formula (VI) above where R 4 : methyl group, R 8 : linear organopolysiloxane with vinyl group and m=40

[0078] Example 1-1: 100 parts by mass of organopolysiloxane resin R-A, 37 parts by mass of tetramethyldisiloxane, 35 parts by mass of methanol, and 2 parts by mass of a strongly acidic cation exchange resin (Lewatit K2629 manufactured by LANXESS) were added to a 500 mL separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer. Water was added dropwise with stirring so that the hydrolysis rate of the organopolysiloxane was theoretically 100 mol%. After stirring at 25°C for 3 hours, the resulting reaction solution was filtered. Next, the fraction was removed by distillation under reduced pressure (90°C, 1.3 kPa). Further, 0.1 parts by mass of a 1,3-divinyltetramethyldisiloxane complex of Pt(0), 43.5 parts by mass of ethylene glycol monoallyl ether, 14.0 parts by mass of linear organopolysiloxane O-A, and 110.0 parts by mass of toluene were added thereto, and the mixture was heated at 80°C for 2 hours. After that, 5.0 parts by mass of ethylene glycol monoallyl ether was further added, and the mixture was heated at 80°C for 2 hours. After that, unreacted ethylene glycol monoallyl ether and toluene were removed by distillation under reduced pressure (90°C, 1.3 kPa), thereby obtaining a hydroxyl group-containing organopolysiloxane (yield: 180 parts by mass).

[0079] Examples 1-2 to 1-8 Hydroxyl-containing organopolysiloxanes of Examples 1-2 to 1-8 were produced using the same formulation as in Example 1-1, except that the organopolysiloxane resin, linear organopolysiloxane, and the amounts thereof incorporated were changed as shown in Table 1.

[0080] Comparative Example 1-1: 100 parts by mass of organopolysiloxane resin R-A, 37 parts by mass of tetramethyldisiloxane, 35 parts by mass of methanol, and 2 parts by mass of a strongly acidic cation exchange resin (Lewatit K2629 manufactured by LANXESS) were added to a 500 mL separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer, and water was added dropwise with stirring so that the hydrolysis rate of the organopolysiloxane was theoretically 100 mol%. After stirring at 25°C for 3 hours, the resulting reaction solution was filtered. Next, the fraction was removed by distillation under reduced pressure (90°C, 1.3 kPa). Further, 0.1 parts by mass of a 1,3-divinyltetramethyldisiloxane complex of Pt(0) and 59.9 parts by mass of ethylene glycol monoallyl ether were added to the mixture, and the mixture was heated at 80°C for 4 hours. After that, unreacted ethylene glycol monoallyl ether was removed by distillation under reduced pressure (90°C, 1.3 kPa), yielding a hydroxyl group-containing organopolysiloxane (yield: 160 parts by mass).

[0081] Comparative Examples 1-2 to 1-4 Hydroxyl-containing organopolysiloxanes of Comparative Examples 1-2 to 1-4 were produced according to the same recipe as in Comparative Example 1-1, except that the raw material organopolysiloxane resin RA was changed to that shown in Table 1.

[0082]

[0083] The values ​​of a, b, c, d, e, f, g, and h in formula (I), the weight average molecular weight (Mw), and the hydroxyl value of the resulting organopolysiloxane are shown in Table 2.

[0084]

[0085] [2] Preparation of Curable Compositions [Examples 2-1 to 2-8, Comparative Examples 2-1 to 2-6] The organopolysiloxanes obtained in Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4 or the following hydroxyl group-containing polydimethylsiloxanes, the following curing agents, and curing catalysts were mixed at 25°C in the composition ratios (mass ratios) shown in Table 3 to prepare curable compositions.

[0086] <Hydroxyl group-containing polydimethylsiloxane> Hydroxyl group-containing polydimethylsiloxane A: KF-6000 (both terminal carbinol-modified silicone oil, OH value 120 mg KOH / g, manufactured by Shin-Etsu Chemical Co., Ltd.) Hydroxyl group-containing polydimethylsiloxane B: KF-6003 (both terminal carbinol-modified silicone oil, OH value 22 mg KOH / g, manufactured by Shin-Etsu Chemical Co., Ltd.) <Curing agent> Curing agent A: Duranate TPA100 (polyisocyanate-based curing agent, isocyanate content 23.2 mass%, manufactured by Asahi Kasei Corporation) <Curing catalyst> Curing catalyst A: Neostan U-810 (dioctyl tin, manufactured by Nitto Kasei Co., Ltd.)

[0087] [3] Preparation and Evaluation of Cured Film The obtained curable composition was applied to a polished steel plate whose surface had been wiped clean with oil using a bar coater to a thickness of 10 μm, and the applied coating was left to stand for 7 days under conditions of 23° C. and 50% RH to obtain a cured film. The obtained cured film was evaluated for curability and antifouling properties.

[0088] (1) Curability Curability was evaluated by touching the coating film after curing. Coatings that showed no bleeding were rated as ◯, and those that showed bleeding were rated as ×. (2) Stain Resistance Stain resistance was evaluated using Zebra Corporation's Hi-Makie oil-based markers (three colors: black, red, and blue). Straight lines 5 cm long, one for each color, were drawn on the coated surface of the evaluation sample at approximately 1.5 cm intervals. Those that did not repel and remained as lines were rated as ◯, and those that did not repel and remained as lines were rated as ×.

[0089]

[0090] As shown in Table 3, the cured films obtained from the curable compositions of Examples 2-1 to 2-8 exhibited excellent curability and high antifouling properties. On the other hand, the cured films obtained from the compositions of Comparative Examples 2-1 to 2-4, which used a hydroxyl-containing organopolysiloxane in which f and g in formula (I) were 0, exhibited excellent curability but did not exhibit antifouling properties. Furthermore, the cured films obtained from the compositions of Comparative Examples 2-5 and 2-6, which used a silicone oil modified with carbinol at both ends, exhibited excellent antifouling properties but poor curability, and bleedout was observed.

Claims

1. A hydroxyl-containing organopolysiloxane represented by the following formula (I): (In the formula, R 1 are each independently a hydrogen atom, or a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom; R 2 is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and R 3 and R 4 are each independently a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms, each of which may be substituted with a halogen atom; R 5 represents a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms, which may be substituted with a halogen atom; R 6 are each independently a hydrogen atom or a monovalent saturated hydrocarbon group having 1 to 8 carbon atoms, and X 1 and X 2 are each independently a divalent hydrocarbon group having 2 to 12 carbon atoms; a, b, c, and d are each numbers that satisfy 0≦a<1, 0<b≦1, 0≦c≦0.5, 0≦d<1, and a+b+c+d=1; e, f, g, and h are each numbers that satisfy 0≦e≦1, 0≦f<1, 0≦g<1, 0<h<4, and 0<f+g<1, 0<e+2f+g+h<4; k and m are numbers from 0 to 1000; and n is a number from 0 to 400.

2. In the formula (I), R 1 2. The hydroxyl group-containing organopolysiloxane according to claim 1, wherein each of the groups independently represents a methyl group or a phenyl group.

3. In the formula (I), R 2 3. The hydroxyl group-containing organopolysiloxane according to claim 1, wherein is a hydrogen atom or a methyl group.

4. The hydroxyl-containing organopolysiloxane according to any one of claims 1 to 3, wherein in formula (I), b is a number satisfying 0.5≦b≦1.

5. The hydroxyl-containing organopolysiloxane according to any one of claims 1 to 4, wherein a and d in formula (I) are 0.

6. In the formula (I), R 3 The hydroxyl group-containing organopolysiloxane according to any one of claims 1 to 5, wherein is a methyl group.

7. In the formula (I), R 4 is a methyl group, and R 5 is a methyl group or a vinyl group, and X 1 The hydroxyl group-containing organopolysiloxane according to any one of claims 1 to 6, wherein is an ethylene group, and k and m are numbers from 5 to 150.

8. In the formula (I), R 6 is a hydrogen atom, and X 2 The hydroxyl group-containing organopolysiloxane according to any one of claims 1 to 7, wherein is an alkylene group having 3 carbon atoms and n is 1.

9. The hydroxyl-containing organopolysiloxane according to any one of claims 1 to 8, which has a weight average molecular weight (Mw) of 1,000 to 500,000 in terms of polystyrene as determined by gel permeation chromatography.

10. (Step α): A step of obtaining an organopolysiloxane having SiH groups by a hydrolysis condensation reaction between an organopolysiloxane represented by the following formula (II) and a silane compound represented by the following formula (III) or by an equilibration reaction using an acid catalyst between an organopolysiloxane represented by the following formula (II) and a disiloxane compound represented by the following formula (IV), and (In the formula, R 1 , R 2 , a, b, c, and d are the same as above, and i is a number satisfying 0<i<4.) (In the formula, R 3 is the same as above, and R 7 is a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 4 carbon atoms.) (Step β): A step of subjecting the organopolysiloxane having SiH groups obtained in the above (Step α) to a hydrosilylation reaction with a compound represented by the following formula (V), a compound represented by the following formula (VI), or both of them, and a compound represented by the following formula (VII): (In the formula, R 4 , R 5 , R 6 , m and n are the same as above, and R 8 and R 9 is a monovalent aliphatic unsaturated hydrocarbon group having 2 to 12 carbon atoms, and p is a number from 0 to 1,000.

11. A curable composition comprising the hydroxyl-containing organopolysiloxane according to any one of claims 1 to 9 and a curing agent capable of reacting with hydroxyl groups.

12. A coating agent comprising the curable composition according to claim 11.

13. A cured film formed from the curable composition according to claim 11.

14. A coated article comprising a substrate and the cured film of claim 13 formed on at least one surface of the substrate directly or via one or more other layers.

Images