Reactive silicon group-containing organopolysiloxane and surface treatment agent

Abstract

To provide a reactive silicon group-containing organopolysiloxane capable of forming a film excellent in water repellency, water sliding property and durability.SOLUTION: A reactive silicon group-containing organopolysiloxane containing, in one molecule, two groups represented by the following structural formula (1) bonded to a silicon atom at a terminal of a linear organopolysiloxane: (R1, R2, and R5 each independently represent hydrogen atoms, aliphatic saturated hydrocarbons having 1 to 10 carbon atoms, or aryl groups having 6 to 10 carbon atoms, R3 and R4 each independently represent aliphatic saturated hydrocarbons having 1 to 10 carbon atoms, or aryl groups having 6 to 10 carbon atoms, Z represents oxygen atoms, alkylene groups having 2 to 12 carbon atoms, or alkylenearylene groups having 8 to 12 carbon atoms, m represents an integer of 0 to 2, provided that when Z is an alkylene group, m is 2, and a line with a wavy line represents a bond). ) SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to reactive silicon group-containing organopolysiloxanes and surface treatment agents, and more specifically to organopolysiloxanes having, as reactive silicon groups, organosilicon groups that can react to form siloxane bonds, and cured products containing the same. [Background technology]

[0002] Conventionally, surface treatment agents containing fluoroalkylsilanes or amino-modified polysiloxanes have been proposed as water-repellent treatment agents for glass (see Patent Documents 1 to 6). Although water-repellent films formed from these surface treatment agents have excellent water repellency, they lack sufficient water-repellency for water droplets to slide off the film surface. For example, when applied to automobile window glass, improvement in water-slippage is required to ensure good visibility during rainfall.

[0003] In this regard, Patent Document 7 proposes a surface treatment agent containing a linear organopolysiloxane having a reactive group at one end and an alkoxy group-containing organosilicon compound as a composition that provides a water-repellent coating film that combines water repellency and water sliding properties. However, the water-repellent film formed from the surface treatment agent of Patent Document 7 does not have sufficient durability against impact and abrasion, making it difficult to maintain water repellency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-224668 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-137775 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-173491 [Patent Document 4] Japanese Patent Application Publication No. 10-102046 [Patent Document 5] Japanese Patent Application Laid-Open No. 2003-160361 [Patent Document 6] Japanese Patent Application Publication No. 09-176622 [Patent Document 7] Japanese Patent Application Publication No. 11-315276 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a reactive silicon group-containing organopolysiloxane capable of forming a coating that is excellent in water repellency, water sliding properties, and durability, and a surface treatment agent containing the same. [Means for solving the problem]

[0006] As a result of extensive research aimed at solving the above problems, the present inventors discovered that a linear organopolysiloxane having, at both molecular chain terminals, an organoxymethyl group and a silyl group to which two organoxy groups are bonded as reactive silicon groups can give a coating that exhibits excellent water repellency, water sliding properties, and durability, and thus completed the present invention.

[0007] That is, the present invention is 1. A reactive silicon group-containing organopolysiloxane containing two groups represented by the following structural formula (1) per molecule, bonded to terminal silicon atoms of a linear organopolysiloxane: [ka] (In the formula, R 1 and R 2 each independently represents a hydrogen atom, an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms; R 3 each independently represents an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; R 4 each independently represents an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; R 5each independently represents a hydrogen atom, an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms; Z represents an oxygen atom, an alkylene group having 2 to 12 carbon atoms, or an alkylenearylene group having 8 to 12 carbon atoms; m is an integer of 0 to 2, provided that when Z is an alkylene group, m is 2; and the wavy line represents a bond. 2. A reactive silicon group-containing organopolysiloxane 1 represented by the following formula (2): [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , m and Z have the same meanings as above, and n is an integer of 1 to 100. 3. A surface treatment agent containing the reactive silicon group-containing organopolysiloxane of 1 or 2, its hydrolysis condensate, or both; 4. The surface treatment agent according to claim 3, further comprising an acid catalyst; 5. Articles with the surface treatment agent 3 attached to provide. [Effects of the Invention]

[0008] The reactive silicon group-containing organopolysiloxane of the present invention is capable of forming a coating that has excellent water repellency, water sliding properties, and durability, and is therefore suitable for use as a surface treatment agent for the water repellency treatment of textile products, transportation vehicle glass, and vehicle bodies. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be specifically described below. The reactive silicon group-containing organopolysiloxane of the present invention is a reactive silicon group-containing organopolysiloxane that contains, per molecule, two groups represented by the following structural formula (1) bonded to terminal silicon atoms of a linear organopolysiloxane:

[0010] [ka]

[0011] In formula (1), R 1 and R 2 each independently represents a hydrogen atom, an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms; R 3 each independently represents an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; R 4 each independently represents an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; R 5 each independently represents a hydrogen atom, an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms. R 1 , R 2 , R 3 , R 4 and R 5 The aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms may be linear, cyclic, or branched, and specific examples thereof include linear or branched alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. R 1 , R 2 , R 3 , R 4 and R 5 Specific examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, xylyl, α-naphthyl, and β-naphthyl groups. In addition, some or all of the hydrogen atoms of these groups may be substituted with halogen atoms such as F, Cl, or Br, or with a cyano group, and specific examples thereof include a 3-chloropropyl group, a 3,3,3-trifluoropropyl group, and a 2-cyanoethyl group.

[0012] Among these, R 1 , R2 , R 3 , R 4 and R 5 As the alkyl group, a methyl group, an ethyl group, or a phenyl group is preferred, and from the viewpoints of curability, productivity, and cost, a methyl group is more preferred.

[0013] In formula (1), the alkylene group having 2 to 12 carbon atoms for Z preferably has 2 to 8 carbon atoms, and the alkylenearylene group having 8 to 12 carbon atoms preferably has 8 to 10 carbon atoms. Specific examples of preferred Z include, but are not limited to, those represented by the following structural formulas:

[0014] [ka] (In the formula, the wavy line represents a bond.)

[0015] In formula (2), m is an integer of 0 to 2, and is preferably 2 from the viewpoint of improving the durability of the coating. When Z is an alkylene group, m is 2.

[0016] The reactive silicon group-containing organopolysiloxane of the present invention is preferably one represented by the following formula (2).

[0017] [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , m and Z have the same meanings as above.

[0018] In formula (2), n is an integer of 1 to 100, and from the viewpoint of improving the water repellency and water sliding properties of the coating, it is preferably an integer of 5 to 50. If n exceeds 100, the durability of the resulting coating may decrease.

[0019] Specific examples of the reactive silicon group-containing organopolysiloxane of the present invention include, but are not limited to, the following compounds:

[0020] [ka]

[0021] A reactive silicon group-containing organopolysiloxane in which Z in the above formula (1) is an oxygen atom can be obtained by ring-opening polymerization of a cyclotrisiloxane compound such as hexamethylcyclotrisiloxane in the presence of a pentacoordinate silicon catalyst using a triorganosilanol compound such as trimethylsilanol as an initiator, followed by end-capping by reaction with an organoxysilane represented by the following formula (6): Furthermore, a reactive silicon group-containing organopolysiloxane in which Z in the above formula (1) is an alkylene group having 2 to 12 carbon atoms or an alkylenearylene group having 8 to 12 carbon atoms can be obtained by subjecting a linear organopolysiloxane containing alkenyl groups at both ends (hereinafter also referred to as a "linear organopolysiloxane containing alkenyl groups at both ends") to a hydrosilylation reaction with a disiloxane compound represented by the following formula (3) in the presence of a platinum group metal catalyst in air or an inert gas such as nitrogen:

[0022] The linear organopolysiloxane containing alkenyl groups at both ends is preferably one represented by the following formula (4).

[0023] [ka] (In the formula, R 4 , R 5 , m and n have the same meanings as above.)

[0024] In equation (4), R 6 represents an alkenyl group having 2 to 12 carbon atoms or an alkenylaryl group having 8 to 12 carbon atoms. R 6The alkenyl group having 2 to 12 carbon atoms is preferably one having 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a 3-butenyl group, a 5-hexenyl group, and a 7-octenyl group. The alkenylaryl group having 8 to 12 carbon atoms is preferably one having 8 to 10 carbon atoms, and examples thereof include a p-vinylphenyl group and a p-allylphenyl group.

[0025] [ka] (In the formula, R 1 , R 2 and R 3 has the same meaning as above.)

[0026] Specific examples of the disiloxane compound represented by formula (3) include, but are not limited to, those represented by the following structural formulas: Among these, the disiloxane compound represented by formula (5) is preferred.

[0027] [ka]

[0028] The disiloxane compound represented by formula (3) above can be obtained, for example, by subjecting an organoxysilane represented by formula (6) below and a disiloxane compound represented by formula (7) below to an equilibration reaction in the presence of acid and water.

[0029] [ka] (In the formula, R 1 , R 2 and R 3 has the same meaning as above.)

[0030] The reaction ratio of the linear organopolysiloxane containing alkenyl groups at both ends with the disiloxane compound represented by formula (3) is preferably such that 1.6 to 5.0 hydrosilyl groups of the disiloxane compound represented by formula (3) per alkenyl group in the alkenyl group-containing organopolysiloxane, and more preferably 1.8 to 4.0 hydrosilyl groups, in order to suppress by-products during the hydrosilylation reaction and to consider the storage stability of the composition and the mechanical properties of the cured product.

[0031] The platinum group metal catalyst used in the hydrosilylation reaction is not particularly limited, and specific examples include chloroplatinic acid, an alcohol solution of chloroplatinic acid, a toluene or xylene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, tetrakistriphenylphosphine platinum, dichlorobistriphenylphosphine platinum, dichlorobisacetonitrile platinum, dichlorobisbenzonitrile platinum, dichlorocyclooctadiene platinum, and the like, as well as supported catalysts such as platinum-carbon, platinum-alumina, and platinum-silica. Among these, zero-valent platinum complexes are preferred from the viewpoint of selectivity during hydrosilylation, and a toluene or xylene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex is more preferred. The amount of platinum group metal catalyst used is not particularly limited, but from the standpoints of reactivity, productivity, etc., it is preferably 0.1 to 1,000 ppm, and more preferably 0.3 to 100 ppm, calculated as the mass of platinum group metal, relative to the total mass of the linear organopolysiloxane containing alkenyl groups at both ends and the disiloxane compound represented by formula (3) above.

[0032] The hydrosilylation reaction can be carried out without a solvent, but a solvent can also be used as needed within a range that does not inhibit the reaction. Specific examples of usable solvents 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 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.

[0033] The reaction temperature for the hydrosilylation reaction is not particularly limited, but is preferably 0 to 200°C, more preferably 40 to 110°C, and even more preferably 60 to 100°C. When a solvent is used, the reaction is preferably carried out at a temperature ranging from 0°C to the boiling point of the solvent. The reaction time is not particularly limited, but is usually about 1 to 60 hours, preferably 1 to 24 hours.

[0034] The surface treatment agent of the present invention contains the reactive silicon group-containing organopolysiloxane described above, its hydrolysis condensate, or both.

[0035] The surface treatment agent of the present invention can be used with the addition of a solvent depending on the intended use and workability. Specific examples of usable organic solvents include esters such as ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, and isobutyl acetate; hydrocarbons such as hexane, cyclohexane, heptane, octane, decane, dodecane, toluene, and xylene; halogenated hydrocarbons such as dichloromethane, 1,1-dichloroethane, and 1,2-dichloroethane; ketones such as methyl ethyl ketone, 2-pentanone, and methyl isobutyl ketone; ethers such as diethylene glycol monomethyl ether and dipropylene glycol monomethyl ether; and alcohols such as ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and isobutyl alcohol. These may be used alone or in combination of two or more.

[0036] The concentration of the reactive silicon group-containing organopolysiloxane of the present invention contained in the surface treatment agent is not particularly limited, but is preferably 0.1 to 20 mass %, more preferably 0.5 to 10 mass %, and even more preferably 0.5 to 5.0 mass %, based on the total mass of the surface treatment agent. By adjusting the concentration within this range, uniform and excellent water repellency and water sliding properties can be imparted to the coating film.

[0037] The surface treatment agent of the present invention may also contain a hydrolysis catalyst for the purpose of accelerating the reaction between the hydrolyzable groups of the reactive silicon group-containing organopolysiloxane and water, thereby accelerating the production of silanol groups. Specific examples of the hydrolysis catalyst include organic acids such as acetic acid, formic acid, methanesulfonic acid, and p-toluenesulfonic acid; and inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid. These may be used alone or in combination of two or more. Among these, methanesulfonic acid, p-toluenesulfonic acid, and sulfuric acid are preferred, and sulfuric acid is more preferred. The amount of hydrolysis catalyst added is preferably 0.1 to 15.0% by mass, more preferably 1.0 to 10.0% by mass, based on the reactive silicon group-containing organopolysiloxane.

[0038] Furthermore, the surface treatment agent of the present invention may contain a curing catalyst. Specific examples of the curing catalyst include titanium catalysts such as titanium tetraisopropoxide, titanium tetra-normal butoxide, titanium tetra-2-ethylhexoxide, and titanium tetraacetylacetonate; tin catalysts such as dibutyltin dilaurate, dibutyltin diacetate, and dioctyltin diacetate; aluminum catalysts such as aluminum sec-butoxide, aluminum trisacetylacetonate, aluminum bisethylacetoacetate, aluminum monoacetylacetonate, and aluminum trisethylacetoacetate; and zirconium catalysts such as normal propyl zirconate, normal butyl zirconate, zirconium tetraacetylacetonate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, and zirconium tetraacetylacetonate. The amount of the curing catalyst added is preferably 0.1 to 15.0% by mass, more preferably 1.0 to 10.0% by mass, based on the reactive silicon group-containing organopolysiloxane.

[0039] The surface treatment agent of the present invention may further contain, other than the reactive silicon group-containing organopolysiloxane of the present invention described above, another organosilicon compound having a hydroxy group or hydrolyzable group bonded to a Si atom, a hydrolysis condensate thereof, or a mixture thereof. Examples of the hydrolyzable group include an alkoxy group, a halogen atom, an acyloxy group, and an isocyanato group. Specific examples of other organosilicon compounds include silane compounds having an alkoxysilyl group, such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, diphenyldimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, trifluoropropyltrimethoxysilane, hexamethyldisilazane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, Examples of silane compounds include silane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, and 3-isocyanatopropyltriethoxysilane. Examples of silane compounds having a halogenated silyl group include methyltrichlorosilane, ethyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, and trifluoroethyltrichlorosilane. There are no particular restrictions on the amount of other organosilicon compounds added, so long as it does not affect the water repellency and water slip properties of the resulting cured coating, but it is preferably no more than 20% by weight based on the reactive silicon group-containing organopolysiloxane of the present invention.

[0040] In addition to the components described above, various additives may be added to the surface treatment agent of the present invention. Examples of the additives include metal oxides, resins, dyes, pigments, ultraviolet absorbers, and antioxidants, and specific examples include silica sol, titania sol, and alumina sol. There are no particular restrictions on the amount of additive added, so long as it does not affect the water repellency and water slip properties of the resulting cured coating, but it is preferably no more than 30% by weight based on the reactive silicon group-containing organopolysiloxane of the present invention.

[0041] The surface treatment agent of the present invention described above can be applied to a substrate and dried to form a water-repellent film on the substrate.

[0042] The material and shape of the substrate are not particularly limited, and specific examples include organic resin substrates such as epoxy resin, phenolic resin, polyimide resin, polycarbonate resin such as polycarbonates and polycarbonate blends, acrylic resin such as poly(methyl methacrylate), polyester resin such as poly(ethylene terephthalate), poly(butylene terephthalate), unsaturated polyester resin, polyamide resin, acrylonitrile-styrene copolymer resin, styrene-acrylonitrile-butadiene copolymer resin, polyvinyl chloride resin, polystyrene resin, blends of polystyrene and polyphenylene ether, cellulose acetate butyrate, and polyethylene resin; metal substrates such as iron plate, copper plate, and steel plate; painted surfaces; glass; ceramic; concrete; slate; textiles; wood, stone, roof tile, (hollow) silica, titania, zirconia, alumina, and other inorganic fillers; and glass fiber products such as glass fiber, glass cloth, glass tape, glass mat, and glass paper.

[0043] The method for applying the surface treatment agent is not particularly limited, and specific examples thereof include spray coating, spin coating, dip coating, roller coating, brush coating, bar coating, flow coating, etc. After the surface treatment agent is applied to the substrate, it is preferable to wipe the coating surface with water.

[0044] Drying after application may be either natural drying or heat drying, but is preferably carried out at a temperature in the range of 5 to 150°C, and more preferably near room temperature (5 to 35°C). At temperatures above 5°C, the reaction rate of the reactive silicon group-containing organopolysiloxane of the present invention increases, making it possible to obtain a water-repellent film with sufficient durability in a short period of time. At temperatures below 150°C, modification and thermal decomposition of the reactive silicon group-containing organopolysiloxane of the present invention can be suppressed.

[0045] The thickness of the water-repellent film is not particularly limited, but is preferably 100 nm or less in consideration of transparency and mechanical strength of the film. Furthermore, the water-repellent film preferably has a water contact angle of 100° or more, particularly 103° or more, with a 2 μl water droplet, and a sliding angle of 45° or less, particularly 30° or less. It also preferably has a haze value of 5 or less, more preferably 1 or less, and even more preferably 0.5 or less.

[0046] The surface treatment agent of the present invention can be applied directly to the surface of a substrate to form a water-repellent film (cured film), but it is preferable to interpose an underlayer formed from a hydrolysis product of a silicon compound having a hydrolyzable group other than the reactive silicon group-containing organopolysiloxane of the present invention between the surface of the substrate and the water-repellent film. The provision of such an underlayer strengthens the bond between the water-repellent film and the substrate, improving the durability of the water-repellent film of the present invention.

[0047] As the organosilicon compound used to form the underlayer, an isocyanate silane compound represented by the following general formula (8) is suitable, considering that it has high hydrolysis property and forms an underlayer on a substrate at around room temperature (5 to 35°C).

[0048] [ka] (In the formula, k represents 0 or 1.)

[0049] The water-repellent film formed from the surface treatment agent of the present invention described above has excellent water repellency, water sliding properties, and durability, and can therefore be suitably used for water-repellent treatment of textile products, glass of transportation vehicles, and car bodies. In particular, when applied to window glass or mirrors, it can efficiently prevent reduced visibility due to the adhesion of water droplets in rainy weather. [Example]

[0050] The present invention will be explained in more detail below with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0051] [1] Synthesis of disiloxane compounds [Synthesis Example 1] Synthesis of disiloxane compound (5) [ka]

[0052] A 300 mL separable flask equipped with a stirrer, reflux condenser, and thermometer was charged with 200 g of trimethoxy(methoxymethyl)silane and 40.4 g of 1,1,3,3-tetramethyldisiloxane, and 1.2 g of concentrated sulfuric acid (98% by mass) was added dropwise with stirring at 7° C. After completion of the dropwise addition, the mixture was stirred for 5 hours at 25° C. Subsequently, 6 g of Kyoward (registered trademark) 500SH (Kyowa Chemical Industry Co., Ltd.) was added, and the mixture was stirred for 1 hour. The reaction solution was then removed by filtration and distilled (distillation temperature 90° C., vacuum 17 kPa) to obtain disiloxane compound (5). 1 H-NMR (CDCl3): δ4.46~4.61ppm(s, 1H, -SiH), 3.41~3.34ppm(s, 9H, -Si(OCH3)2, -OCH3), 3.15~3.13ppm(s, 2H, -CH2-), 0.00~0.02ppm(s, 6H, -SiCH3)

[0053] [2] Synthesis of reactive silicon-containing organopolysiloxane [Example 1-1] Synthesis of reactive silicon group-containing organopolysiloxane a A 1,000 mL separable flask equipped with a stirrer, thermometer, and Dimroth condenser was charged with 315 g of linear organopolysiloxane (9) containing silanol groups at both ends, and then 93.4 g of vinyltrimethoxysilane and 3.15 g of t-butylamine were added with stirring at 60°C, and the reaction was carried out for 5 hours. After completion of the reaction, the solvent was distilled off at 120°C and a vacuum of 1.3 kPa for 3 hours to obtain linear organopolysiloxane (10) containing alkenyl groups at both ends.

[0054] [ka]

[0055] Next, 200 g of the linear organopolysiloxane (10) containing alkenyl groups at both ends and a toluene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (50 ppm by mass as platinum) were placed in a 1,000 mL separable flask equipped with a stirrer, a thermometer, an ester adapter, and a Dimroth condenser. Next, 80.8 g of the disiloxane compound (5) was added dropwise with stirring at 60°C, and the reaction was carried out at 60°C for an additional 3 hours. 1 The reaction was terminated when H-NMR analysis confirmed that the peaks derived from the vinyl groups in the raw material had completely disappeared and that the peaks derived from the target product had been detected. After the reaction was completed, the solvent was distilled off at 100°C under a vacuum of 1.3 kPa for 3 hours to obtain reactive silicon group-containing organopolysiloxane a.

[0056] [ka]

[0057] [Example 1-2] Synthesis of reactive silicon group-containing organopolysiloxane b A 1,000 mL separable flask equipped with a stirrer, thermometer, and Dimroth condenser was charged with 315 g of linear organopolysiloxane (9) containing silanol groups at both ends, and then 146 g of 7-octenyltrimethoxysilane and 3.15 g of t-butylamine were added with stirring at 60°C, and the reaction was carried out for 5 hours. After completion of the reaction, the solvent was distilled off at 120°C and a vacuum of 1.3 kPa for 3 hours to obtain linear organopolysiloxane (11) containing alkenyl groups at both ends.

[0058] Next, 200 g of the linear organopolysiloxane (11) containing alkenyl groups at both ends and a toluene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (50 ppm by mass as platinum) were placed in a 1,000 mL separable flask equipped with a stirrer, a thermometer, an ester adapter, and a Dimroth condenser. Next, 75.8 g of the disiloxane compound (5) was added dropwise with stirring at 60°C, and the reaction was carried out at 60°C for an additional 3 hours. 1 The reaction was terminated when H-NMR analysis confirmed that the peaks derived from the vinyl groups in the raw material had completely disappeared and that the peaks derived from the target product had been detected. After the reaction was completed, the solvent was distilled off at 100°C under a vacuum of 1.3 kPa for 3 hours to obtain reactive silicon group-containing organopolysiloxane b.

[0059] [ka]

[0060] [Example 1-3] Synthesis of reactive silicon group-containing organopolysiloxane c A 1,000 mL separable flask equipped with a stirrer, thermometer, and Dimroth condenser was charged with 315 g of linear organopolysiloxane (9) containing silanol groups at both ends, and then 140 g of p-styryltrimethoxysilane and 3.15 g of t-butylamine were added with stirring at 60°C, and the reaction was carried out for 5 hours. After completion of the reaction, the solvent was distilled off at 120°C and a vacuum of 1.3 kPa for 3 hours to obtain linear organopolysiloxane (12) containing alkenyl groups at both ends.

[0061] Next, 200 g of the linear organopolysiloxane (12) containing alkenyl groups at both ends and a toluene solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (50 ppm by mass as platinum) were placed in a 1,000 mL separable flask equipped with a stirrer, a thermometer, an ester adapter, and a Dimroth condenser. Next, 78.4 g of the disiloxane compound (5) was added dropwise with stirring at 60°C, and the reaction was carried out at 60°C for an additional 3 hours. 1 The reaction was terminated when H-NMR analysis confirmed that the peaks derived from the vinyl groups in the raw material had completely disappeared and that the peaks derived from the target product had been detected. After the reaction was completed, the solvent was distilled off at 100°C for 3 hours at a vacuum of 1.3 kPa to obtain reactive silicon group-containing organopolysiloxane c.

[0062] [ka]

[0063] [Examples 1-4] Synthesis of reactive silicon group-containing organopolysiloxane d A 1,000 mL separable flask equipped with a stirrer, thermometer, and Dimroth condenser was charged with 315 g of linear organopolysiloxane (9) containing silanol groups at both ends, and then 104 g of trimethoxy(methoxymethyl)silane and 3.15 g of t-butylamine were added with stirring at 60°C, and the reaction was carried out for 5 hours. After the reaction was complete, the solvent was distilled off at 120°C and a vacuum of 1.3 kPa for 3 hours to obtain reactive silicon group-containing organopolysiloxane d.

[0064] [ka]

[0065] [2] Preparation of surface treatment agent [Example 2-1] A surface treatment agent was obtained by adding 0.920 g of the reactive silicon group-containing organopolysiloxane a obtained in Example 1-1 and 0.080 g of 98% by mass sulfuric acid to 19.0 g of ethyl acetate and mixing them.

[0066] [Example 2-2] A surface treatment agent was obtained in the same manner as in Example 2-1, except that reactive silicon group-containing organopolysiloxane a was replaced with reactive silicon group-containing organopolysiloxane b obtained in Example 1-2.

[0067] [Example 2-3] A surface treatment agent was obtained in the same manner as in Example 2-1, except that reactive silicon group-containing organopolysiloxane a was replaced with reactive silicon group-containing organopolysiloxane c obtained in Example 1-3.

[0068] [Example 2-4] A surface treatment agent was obtained in the same manner as in Example 2-1, except that reactive silicon group-containing organopolysiloxane a was replaced with reactive silicon group-containing organopolysiloxane d obtained in Example 1-4.

[0069] [Comparative Example 2-1] A surface treatment agent was obtained in the same manner as in Example 2-1, except that the linear organopolysiloxane a containing alkenyl groups at both ends was changed to organopolysiloxane e represented by the following formula:

[0070] [ka]

[0071] Tissue paper was impregnated with each of the surface treatment agents prepared in Examples 2-1 to 2-4 and Comparative Example 2-1 above, and then wipe-coated onto a glass substrate. After air-drying for 1 minute, the tissue paper was impregnated with water, and the coated surface of the glass substrate was wiped up. Air-drying was carried out at 25°C for 1 hour to obtain a glass substrate with a water-repellent film. The obtained glass substrate with a water-repellent film was used to carry out the following evaluation tests (1) to (4). The results are shown in Table 1. The water contact angle and water droplet sliding angle (sliding angle) were measured using a contact angle meter equipped with a sliding unit (Drop Master DM-701, manufactured by Kyowa Interface Science Co., Ltd.). (1) Water repellency 2 μL of water was dropped onto the treated surface of the water-repellent film-coated glass substrate, and the water contact angle was measured. (2) Hydrophobicity 2 μL of water was dropped onto the treated surface of the water-repellent film-coated glass substrate, and the sliding angle was measured. (3) Ultrasonic cleaning test The glass substrate with the water-repellent film was immersed in a 1% by mass aqueous solution of surfactant (Lipon F, manufactured by Lion Hygiene Co., Ltd.) and irradiated with ultrasound (100 W, 42 kHz) for 30 minutes. After the test, the water-repellent film-coated glass substrate was evaluated for water repellency and water sliding properties using the same procedures as in (1) and (2) above. (4) Abrasion test An abrasion test was conducted on the treated surface of the water-repellent coated glass substrate using a 2cm x 2cm flannel cloth, a 1.2kg load, and 1,200 strokes. After the test, the water-repellent coated glass substrate was evaluated for water repellency and water slippage using the same procedures as in (1) and (2) above.

[0072] [Table 1]

[0073] As shown in Table 1, the glass substrates with water-repellent films obtained in Examples 2-1 to 2-4 have good water repellency and water sliding properties initially, after the ultrasonic cleaning test, and after the abrasion test. On the other hand, it is clear that the water-repellent film-coated glass substrate obtained in Comparative Example 2-1 exhibited a particularly marked decrease in water sliding property after the ultrasonic cleaning test and the abrasion test.

Claims

1. A reactive silicon group-containing organopolysiloxane containing two groups represented by the following structural formula (1) per molecule, which are bonded to silicon atoms at the terminals of a linear organopolysiloxane. 【Chemistry 1】 (In the formula, R 1 and R 2 each independently represents a hydrogen atom, an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms; R 3 each independently represents an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; R 4 each independently represents an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms; R 5 each independently represents a hydrogen atom, an aliphatic saturated hydrocarbon group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms; Z represents an oxygen atom, an alkylene group having 2 to 12 carbon atoms, or an alkylenearylene group having 8 to 12 carbon atoms; m is an integer from 0 to 2, provided that when Z is an alkylene group, m is 2; and the wavy line represents a bond.

2. 2. The reactive silicon group-containing organopolysiloxane according to claim 1, which is represented by the following formula (2): 【Chemistry 2】 (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , m and Z have the same meanings as above, and n is an integer of 1 to 100.

3. 3. A surface treatment agent comprising the reactive silicon group-containing organopolysiloxane of claim 1 or 2, its hydrolysis condensate, or both.

4. The surface treatment agent according to claim 3, further comprising an acid catalyst.

5. An article having the surface treatment agent according to claim 3 adhered thereto.

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