Organic polysiloxanes, their manufacturing methods, adhesion promoters, waterborne coating compositions and primer compositions

Abstract

The present invention provides a water-soluble organic polysiloxane with excellent storage stability as shown in the following formula (1). (where R is in the formula) 1 is a monovalent hydrocarbon group having 1 to 10 carbon atoms, R 2. Each is an independent monovalent hydrocarbon group with 1 to 10 carbon atoms that can be substituted with an epoxypropoxy group, R 3 is a monovalent saturated hydrocarbon group with 1 to 6 carbon atoms, but R At least a portion of 3 consists of monovalent saturated hydrocarbon groups with 3 to 6 carbon atoms; a, b, c, and d are numbers that satisfy a ≥ 0.5, b ≥ 0, c ≥ 0, d ≥ 0 and a + b + c + d = 1; x and y are numbers that satisfy x ≥ 1 and 0 < y ≤ 0.5.

Description

Organopolysiloxane, method for producing the same, adhesion-imparting agent, water-based coating composition, and primer composition The present invention relates to an organopolysiloxane, a method for producing the same, an adhesion-imparting agent, a water-based coating composition, and a primer composition. More specifically, the present invention relates to an organopolysiloxane comprising a siloxane unit containing a 3-glycidoxypropyl group as a constituent unit and having a silanol group, a method for producing the organopolysiloxane, an adhesion-imparting agent formed from the organopolysiloxane, and a water-based coating composition and a primer composition containing the organopolysiloxane. Compounds having two or more different reactive functional groups in one molecule are known as coupling agents for bonding dissimilar materials. Silane coupling agents having a hydrolyzable silyl group, such as an alkoxysilyl group, as one of the reactive groups, and further having various organic reactive groups, such as primary amine groups, secondary amine groups, glycidyl ether groups, methacrylate groups, urea groups, vinyl groups, mercapto groups, and isocyanate groups, are known as primers for improving the adhesion of coatings and as adhesion promoters added to coating compositions. There are also reports of compositions containing reactive organopolysiloxanes obtained by hydrolyzing and condensing hydrolyzable silyl groups using a silane coupling agent as a monomer. For example, Patent Document 1 proposes a coating material and adhesive sheet containing an organosilsesquioxane having an epoxy group, while Patent Documents 2 to 4 propose using relatively low molecular weight oligomers obtained by partially hydrolyzing and condensing a silane coupling agent having an epoxy group as an adhesion promoter. Compared to silane coupling agents, the advantages of using oligomers and / or polymers formed by hydrolysis and condensation include, firstly, their high molecular weight and low volatility, which eliminate concerns about a reduction in active ingredients during drying and other steps. Furthermore, they generate less volatile organic compounds (VOCs). Considering the recent trend toward water-based and solvent-free solvent-based coatings to reduce environmental impact, oligomers that have been partially hydrolyzed beforehand, compared to silane coupling agents that generate alcohols upon hydrolysis, are suitable materials for these requirements because they generate less alcohol per unit mass of active ingredients. To further reduce VOCs, aqueous solutions have been proposed that include hydrolysis-condensation products obtained by completely hydrolyzing a silane coupling agent and removing the generated alcohol. Patent Documents 5 to 7 propose aqueous silane compositions that include hydrolysis-condensation products containing functional groups such as amino groups, thiol groups, and carboxyl groups. Patent Document 8 proposes an aqueous silane composition that includes hydrolysis-condensation products containing ethylene glycol groups. Such aqueous silane compositions are all hydrolyzed condensates of silane coupling agents and are highly active. From the perspective of handling and stability, they must be prepared as aqueous solutions, but their storage stability is not sufficient. [Prior Art] [Patent] [Patent Document 1] Japanese Patent Application Publication No. 2019-143161 [Patent Document 2] International Publication No. 2018 / 34232 [Patent Document 3] Japanese Patent Application Publication No. 2018-127507 [Patent Document 4] Japanese Patent Application Publication No. 2022-27097 [Patent Document 5] European Patent Specification No. 0675128 [Patent Document 6] Japanese Patent Application Publication No. 2016-44278 [Patent Document 7] Japanese Patent Application Publication No. 2015-34097 [Patent Document 8] Japanese Patent Application Publication No. 2017-114852 [Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and its object is to provide a water-soluble organopolysiloxane having an organic functional group and excellent storage stability. [Solution to the Problem] The present inventors have diligently conducted studies to address the above-mentioned issues and have discovered that an organopolysiloxane having a specific amount of siloxane units containing a 3-glycidoxypropyl group and a silanol group exhibits excellent storage stability. Furthermore, a water-based composition containing the organopolysiloxane exhibits excellent adhesion and is suitable as a primer. This has ultimately led to the present invention. That is, the present invention provides: 1. An organopolysiloxane represented by the following formula (1), (Where R 1 is a monovalent hydrocarbon group having 1 to 10 carbon atoms, R 2 Each is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a glycidoxy group, R 3 is a monovalent saturated hydrocarbon group having 1 to 6 carbon atoms, but R 3 At least a portion of the carbon atoms is a monovalent saturated hydrocarbon group having 3 to 6 carbon atoms, a, b, c, and d are numbers satisfying a≧0.5, b≧0, c≧0, d≧0, and a+b+c+d=1, and x and y are numbers satisfying x≧1, 0<y≦0.5. 2. The organopolysiloxane as described in 1, wherein R 3is a monovalent saturated hydrocarbon group having 3 or 4 carbon atoms. 3. The organopolysiloxane according to 1 or 2, wherein b, c, d, and y are numbers satisfying b=0, c=0, d=0, and 0.01≦y≦0.1. 4. A method for producing an organopolysiloxane, which is a method for producing the organopolysiloxane according to any one of items 1 to 3, comprising: (co)hydrolyzing and condensing silane monomers comprising a 3-glycidoxypropyl group-containing silane compound represented by the following formula (i), optionally a silane compound represented by the following formula (ii), a silane compound represented by the following formula (iii), and a silane compound represented by the following formula (iv), in the presence of an alcohol represented by the following formula (v), adding 0.8 to 1.1 times the molar amount of water per mole of Si(OR) groups (R is a monovalent saturated hydrocarbon group having 1 to 6 carbon atoms) of the silane monomers, and performing a (co)hydrolysis condensation reaction of the silane monomers under acidic conditions; (Where R 1 、R 2 and R are the same as above, R 0 is a monovalent saturated hydrocarbon group having 3 to 6 carbon atoms). 5. An adhesion-imparting agent comprising the organopolysiloxane described in any one of 1 to 3. 6. An aqueous coating composition comprising the organopolysiloxane described in any one of 1 to 3. 7. A primer composition comprising the organopolysiloxane described in any one of 1 to 3. [Effects of the Invention] The organopolysiloxane of the present invention possesses highly reactive epoxy groups, making it excellent for modifying organic resins and improving adhesion to resin substrates. Its excellent stability also extends its usable life. Furthermore, the organopolysiloxane of the present invention possesses silanol groups, resulting in excellent reactivity with inorganic substrates and high water solubility, making it useful as an additive for water-based coating compositions. [Modes of carrying out the invention] The present invention will be described in detail below. (1) Organopolysiloxane The organopolysiloxane of the present invention is represented by the following general formula (1). In the above formula, R 1 It is a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and n-decyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl, allyl, butenyl, hexenyl, and octenyl; and aryl groups such as phenyl and naphthyl. Among these, methyl, ethyl, n-propyl, and phenyl are preferred, methyl and ethyl are more preferred, and methyl is particularly preferred. R 2 Each of them is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, which may be substituted with a glycidoxy group. Specific examples thereof include the group having the same carbon atoms as those in the above R 1 The same as those exemplified above include glycidoxy substituted alkyl groups such as glycidoxypropyl, etc. Among them, methyl, ethyl, n-propyl, glycidoxypropyl, and phenyl are preferred, methyl and ethyl are more preferred, and methyl is particularly preferred. R 3 It is a monovalent saturated hydrocarbon group having 1 to 6 carbon atoms and may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, neopentyl, and n-hexyl; and cycloalkyl groups such as cyclohexyl. From the perspective of stability, the organopolysiloxane of the present invention has R 3 At least a portion, preferably all, of R 3 It is a monovalent saturated hydrocarbon group having 3 to 6 carbon atoms, more preferably a monovalent saturated hydrocarbon group having 3 or 4 carbon atoms, particularly preferably a branched alkyl group having 3 or 4 carbon atoms, and even more preferably isopropyl or isobutyl. a, b, c, and d represent the molar ratio of each siloxane unit and are numbers satisfying a+b+c+d=1. a is a number greater than or equal to 0.5, preferably a number between 0.5 and 1. If a is less than 0.5, the amount of effective epoxy groups decreases, and the adhesion-enhancing effect cannot be expected. In addition, the organopolysiloxane represented by formula (1) becomes highly viscous, gum-like, or solid, with poor handling properties and reduced water solubility. b is a number greater than or equal to 0, preferably a number between 0 and 0.5. From the perspective of the amount of epoxy groups contained in the organopolysiloxane of the present invention, 0 is preferred. c is a number greater than or equal to 0, preferably a number between 0 and 0.5. From the perspective of the reactivity of the epoxy groups, 0 is preferred. d is a number greater than or equal to 0, preferably a number between 0 and 0.5. From the perspective of storage stability, 0 is preferred. x and y represent the number of moles of hydroxyl groups and alkoxy groups bonded to 1 mole of Si atoms, respectively. x is a number greater than 1, and is preferably 1 to 2 from the perspective of storage stability. If it is less than 1, the water solubility and reactivity of the organic polysiloxane with the inorganic substrate are poor. y is a number that satisfies 0<y≦0.5, and is preferably 0<y≦0.3 from the perspective of reducing alcohol produced by hydrolysis, and is more preferably 0.01≦y≦0.1. When y is 0, although the organic polysiloxane of the present invention is a material that does not substantially produce alcohol and has a low environmental load, due to the high reactivity of the silanol group, the storage stability is insufficient, resulting in a problem of being unsuitable for practical use. Due to the above-mentioned R 3Since it contains a monovalent saturated hydrocarbon group having 3 to 6 carbon atoms, the reactivity of the active silanol group can be controlled, and the desired improvement in storage stability can be expected. The organopolysiloxane of the present invention is preferably one represented by the following formula (1a). In formula (1a), R 3 The system is the same as above, a1=1, x1 and y1 are numbers that satisfy x1≧1 and 0.01≦y≦0.1. The weight average molecular weight of the organopolysiloxane of the present invention is preferably 500 to 10,000, more preferably 500 to 1,000, from the viewpoint of water solubility and handling properties. Furthermore, the weight average molecular weight in the present invention is a standard polystyrene conversion value measured by gel permeation chromatography (GPC). Furthermore, the kinematic viscosity of the organopolysiloxane of the present invention is preferably 100 to 500 mm 2 / s, preferably 200-450mm 2 The kinematic viscosity is a value measured at 25°C using a Cannon-Fenske viscometer. The organopolysiloxane of the present invention preferably contains water and free alcohol as impurities at a content of 1% by mass or less. While water does not constitute a VOC, its presence in excess can react with epoxy groups. Therefore, it is best to minimize its presence during long-term storage of the organopolysiloxane of the present invention. (2) Method for producing organopolysiloxane The method for producing the organopolysiloxane of the present invention is not particularly limited, but for example, it can be produced by (co)hydrolyzing and condensing a silane compound containing a 3-glycidoxypropyl group such as 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane represented by the following formula (i), and optionally a silane compound represented by the following formula (ii), a silane compound represented by the following formula (iii), and a silane compound represented by the following formula (iv) under acidic conditions in the presence of an alcohol having 3 to 6 carbon atoms represented by the following formula (v). In the above formula, R 1 and R 2 R is the same as above. Each R is independently a monovalent saturated hydrocarbon group having 1 to 6 carbon atoms, which may be linear, branched or cyclic. Specific examples thereof include the following: 3 The same groups as those exemplified. Among them, methyl and ethyl are preferred. 0It is a monovalent saturated hydrocarbon group having 3 to 6 carbon atoms, preferably 3 or 4 carbon atoms. 0 The monovalent saturated hydrocarbon group may be linear, branched or cyclic. Specific examples thereof include the following: 3 Among the exemplified groups, those having 3 to 6 carbon atoms are preferably branched monovalent saturated hydrocarbon groups having 3 or 4 carbon atoms, more preferably branched alkyl groups having 3 or 4 carbon atoms, and particularly preferably isopropyl and isobutyl groups. Specific examples of the silane compound containing a 3-glycidoxypropyl group represented by formula (i) include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane, as well as 3-glycidoxypropyltripropoxysilane and 3-glycidoxypropyltributoxysilane. Specific examples of the silane compound represented by formula (ii) include trialkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, and decyltriethoxysilane. Specific examples of the silane compound represented by formula (iii) include dialkoxysilanes such as dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, methylethyldimethoxysilane, methylethyldiethoxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, cyclopentylmethyldimethoxysilane, cyclohexylmethyldimethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methyloctyldimethoxysilane. Specific examples of the silane compound represented by formula (iv) include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Furthermore, hydrolysis-condensation products of these silanes may also be used. These silanes may be used alone or in combination of two or more. The amount of the silane monomers used is preferably adjusted according to the molar ratio of the siloxane units constituting the desired organopolysiloxane (the values ​​of a to d in formula (1)). Examples of the alcohol represented by formula (v) include n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, pentanol, neopentyl alcohol, hexanol, and cyclohexanol. Alcohols having 3 or 4 carbon atoms are preferred, and isopropanol and isobutanol are more preferred. The amount of alcohol added is preferably 0.1 to 5 mol, more preferably 0.5 to 2 mol, relative to 1 mol of the silane monomer. The amount of water used for hydrolysis of the silane monomer is, from the viewpoint of suppressing the reaction with the epoxy group and reducing the number of residual Si(OR) groups (R is the same as described above; the same applies hereinafter) such as alkoxysilyl groups, in an amount of 0.8 to 1.1 times the mole of Si(OR) groups such as alkoxysilyl groups, preferably 1 to 1.1 times the mole of Si(OR) groups such as alkoxysilyl groups, relative to 1 mole of Si(OR) groups such as alkoxysilyl groups. The acid component used to adjust the acidic conditions during the hydrolysis reaction is not particularly limited as long as it is a commercially available Brünnst acid. Formic acid, acetic acid, citric acid, hydrochloric acid, and nitric acid are preferred due to their availability. The amount of acid used is preferably 0.0001 to 0.01 mol per 1 mol of the silane monomer to suppress the increase in molecular weight of the resulting organopolysiloxane due to excessive dehydration condensation between silanol groups and the decrease in water solubility due to a decrease in the number of silanol groups. In the hydrolysis reaction, organic solvents other than alcohols may be used as needed, as long as they do not hinder the reaction. Suitable organic solvents are preferably those that are compatible with the water of the reaction raw materials, preferably esters, ketones, and ethers. Furthermore, considering the distillation conditions for removing the generated alcohol, the boiling point of the organic solvent should be low, preferably below 150°C at atmospheric pressure. Specific examples of esters include ethyl acetate and butyl acetate. Specific examples of ketones include acetone, methyl ethyl ketone, and cyclohexanone. Specific examples of ethers include tetrahydrofuran, tetrahydropyran, and dioxane. The hydrolysis reaction temperature is preferably 55-70°C, and the reaction time is preferably 1-5 hours. Furthermore, after the hydrolysis reaction of the silane monomer, a step of distilling off water, alcohol generated by the hydrolysis of the alkoxysilyl groups, and the aforementioned organic solvent is preferably performed under reduced pressure at a temperature range of 30-80°C. The organopolysiloxane of the present invention can be used as an adhesion-imparting agent in curable compositions such as coatings, and can also be used as a water-based coating composition due to its excellent water solubility. (3) Water-Based Coating Composition The water-based coating composition of the present invention contains the above-mentioned organopolysiloxane. As the above-mentioned organopolysiloxane, one type may be used alone, or two or more types may be used in combination. The water-based coating composition of the present invention preferably contains water as a solvent, and is particularly preferably an aqueous solution containing only water as a solvent. The blending amount of the above-mentioned organopolysiloxane in the composition is preferably 5 to 50% by mass, more preferably 10 to 40% by mass. Specific examples of water-based coating compositions include compositions containing water-based resins, such as water-based epoxy resin compositions and water-based urethane resin compositions. The organopolysiloxane of the present invention can be used as a component of such water-based resin compositions. Specific examples of water-based resins include, in addition to water-based epoxy resins and water-based polyurethane resins, water-based polyester resins and water-based acrylic resins. Furthermore, the water-based coating compositions of the present invention may contain any additives, such as organic solvents, antioxidants, ultraviolet absorbers, light stabilizers, tackifiers, dispersants, and adhesion promoters, as long as they do not impair the effects of the present invention. The method for preparing the water-based coating composition of the present invention is not particularly limited. For example, a method of mixing the above-mentioned organopolysiloxane, a solvent, an optional water-based resin, and other additives according to a conventional method can be cited. The resulting water-based coating composition can be applied directly or through other layers such as a primer layer onto a specific substrate and dried for 1 to 60 minutes under an environment of 20 to 50° C. and 30 to 60% RH to form a coating film. The substrate is not particularly limited, and examples thereof include plastic moldings, wood products, ceramics, glass, metals, and composites thereof. The method for applying the water-based coating composition is not particularly limited, and can be appropriately selected from conventional methods, such as brush coating, smearing, spraying, dipping, rod coating, flow coating, roller coating, curtain coating, spin coating, and knife coating. (4) Primer composition The organopolysiloxane of the present invention can be used as a coupling component or a water-based reactive binder in a water-based primer composition (coating). The primer composition of the present invention contains the above-mentioned organopolysiloxane, but as the above-mentioned organopolysiloxane, one type can be used alone, or two or more types can be used in combination. In addition, the primer composition of the present invention preferably contains water as a solvent, and is particularly preferably an aqueous solution containing only water as a solvent. The blending amount of the above-mentioned organopolysiloxane in the composition is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass. Furthermore, the primer composition of the present invention can contain any additives within the range that does not hinder the effects of the present invention. As specific examples thereof, the same additives as those exemplified in the water-based coating composition can be cited. The method for preparing the primer composition and the method for forming the primer layer of the present invention are not particularly limited, and the same methods as those for the water-based coating composition can be used. Furthermore, other layers may be formed on the surface of the primer layer. Examples of these other layers include a coating layer formed from a cured film of a water-based resin composition such as a water-based acrylic resin, a water-based polyester resin, a water-based epoxy resin, or a water-based urethane resin. Among these, a coating layer formed from a cured film of a water-based urethane resin composition is preferred. The coating layer can be formed using the same method as for the water-based coating composition. [Example] Hereinafter, the present invention will be described in detail using Examples and Comparative Examples, but the present invention is not limited thereto. In the following examples, unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass," respectively. 1 The conditions for H-NMR measurement are as follows. The kinematic viscosity is the value measured at 25° C. using a Cannon-Fenske viscometer. (1) GPC measurement conditions Apparatus: HLC-8320GPC manufactured by Tosoh Corporation Developing solvent: Tetrahydrofuran (THF) Flow rate: 0.6 mL / min Detector: Differential refractive index detector (RI) Column: TSK Guardcolumn SuperH-H TSKgel SuperHM-N (6.0 mm I.D. × 15 cm × 1) TSKgel SuperH2500 (6.0 mm I.D. × 15 cm × 1) (both manufactured by Tosoh Corporation) Column temperature: 40°C Sample injection volume: 50 μL (2.0% THF solution) Standard: Monodisperse polystyrene (2) 1 H-NMR measurement conditions: Apparatus: AVANCE III 400 manufactured by Burker Corporation; Solvent: CDCl 3 Internal standard: tetramethylsilane (TMS) [1] Synthesis of organic polysiloxane [Example 1-1] In a 1L three-necked flask equipped with a stirring device, a cooling tube, a dropping funnel and a thermometer, 472g (2.0 mol) of 3-glycidoxypropyltrimethoxysilane and 60g of isopropyl alcohol were placed. 108g of 0.2% hydrochloric acid (6.0 mol of water) was added dropwise thereto (the temperature was controlled within the range of 20-40°C during the addition). After the addition was completed, the mixture was stirred at 70°C for 1 hour, and then vacuum distilled at 70°C to remove the alcohol and excess water produced by the hydrolysis reaction, thereby obtaining a colorless transparent liquid organic polysiloxane (Ep1). The kinematic viscosity of the obtained organic polysiloxane at 25°C was 395mm 2 / s, the epoxy functional group content is 198g / mol, and the weight average molecular weight is 608. 1 As a result of H-NMR and GPC analysis, the organopolysiloxane (Ep1) has a structure represented by the following formula (2). 1 H-NMR spectrum. [Example 1-2] The same operation as in Example 1-1 was carried out except that 74 g of isobutyl alcohol was used instead of isopropyl alcohol to obtain a colorless transparent liquid organopolysiloxane (Ep2). The kinematic viscosity of the obtained organopolysiloxane at 25°C was 432 mm 2 / s, the epoxy functional group content is 202g / mol, and the weight average molecular weight is 668. 1 As a result of H-NMR and GPC analysis, the organopolysiloxane (Ep2) had a structure represented by the following formula (3). [Comparative Example 1-1] 472 g (2.0 mol) of 3-glycidoxypropyltrimethoxysilane was placed in a 1L three-necked flask equipped with a stirring device, a cooling tube, a dropping funnel and a thermometer. 108 g of 0.2% hydrochloric acid (6.0 mol of water) was added dropwise thereto (temperature was controlled within the range of 20-40°C during the addition). After the addition was completed, the mixture was stirred at 70°C for 1 hour, and then vacuum distilled at 70°C to remove the alcohol and excess water produced by the hydrolysis reaction, thereby obtaining a colorless, transparent liquid organic polysiloxane (Ep3). The kinematic viscosity of the obtained organic polysiloxane at 25°C was 726 mm 2 / s, the epoxy functional group content is 189g / mol, and the weight average molecular weight is 830. 1 As a result of H-NMR and GPC analysis, the organopolysiloxane (Ep3) had a structure represented by the following formula (4). [Comparative Example 1-2] In a 1L three-necked flask equipped with a stirring device, a cooling tube, a dropping funnel and a thermometer, 141.6g (0.6 mol) of 3-glycidoxypropyltrimethoxysilane and 168g (1.4 mol) of dimethyldimethoxysilane were placed. 82.8g of 0.2% hydrochloric acid (4.6 mol of water) was added dropwise thereto (temperature was controlled within the range of 20-40°C during the addition). After the addition was completed, the mixture was stirred at 70°C for 1 hour, and then vacuum distilled at 70°C to remove the alcohol and excess water produced by the hydrolysis reaction, thereby obtaining a colorless, transparent liquid organopolysiloxane (Ep4). The kinematic viscosity of the obtained organopolysiloxane at 25°C was 181mm 2 / s, the epoxy functional group content is 288g / mol, and the weight average molecular weight is 930. 1The results of H-NMR and GPC analysis showed that the organopolysiloxane (Ep4) had a structure represented by the following formula (5). Furthermore, the organopolysiloxane (Ep4) was insoluble in ion-exchanged water and became turbid, indicating poor water solubility. [2] Storage Stability Evaluation [Examples 2-1, 2-2, Comparative Example 2-1] The kinematic viscosity and water solubility of the organopolysiloxanes (Ep1 to Ep3) synthesized in Examples 1-1, 1-2, and Comparative Example 1-1 were evaluated immediately after production, and after 1 month, 2 months, and 3 months of storage at room temperature and 5°C. The results are shown in Table 1. Water solubility was evaluated by mixing each organopolysiloxane with ion-exchanged water at 25°C to a concentration of 10%. A score of "0" was given for uniform dissolution, and a score of "×" was given for turbidity. As shown in Table 1, Comparative Example 2-1, which uses organopolysiloxane Ep3, which lacks bulky alkoxysilyl groups, exhibits a significant increase in viscosity and decrease in water solubility over time due to the progress of the condensation reaction. This material is only usable immediately after production and is not of practical quality. In contrast, the organopolysiloxanes Ep1 and Ep2 obtained in Examples 1-1 and 1-2 exhibit similar temporal changes at 25°C, but the extent is minimal, with virtually no change observed during storage at 5°C. [3] Preparation and Evaluation of Primer Compositions [Examples 3-1, 3-2, Comparative Examples 3-1 to 3-5] The primer composition described in Table 2 below, diluted with ion-exchanged water to a solid content of 30%, was applied to a polished steel plate and dried for 30 minutes at 25°C and 50% RH. Subsequently, 100 parts of Burnock WD-551 (DIC Corporation), a water-based paint resin, and 30 parts of Burnock DNW-5500 (DIC Corporation), an isocyanate hardener, were mixed and applied using a No. 14 rod coater to form a water-diluted water-based urethane paint. After standing for 3 days at 25°C and 50% RH, the paint was cured at 80°C for 4 hours. The coating film obtained above was evaluated as follows. The results are shown in Table 2. (1) Appearance of coating film The coating film was visually observed to determine if there were any abnormalities. ○: No abnormality △: Coloration ×: Abnormalities such as foreign matter, unevenness, or whitening (2) Initial adhesion In accordance with JIS K5600, 6 cuts were made in the vertical and horizontal directions at intervals of 2 mm in the coating film using a razor blade to create a 25-square grid. After fully adhering a transparent tape (Cellophane, a registered trademark, manufactured by NICHIBAN Co., Ltd.), the coating film was suddenly peeled off at 90°. The number of squares (X) remaining without peeling off was expressed as X / 25. (3) Boiling adhesion The adhesion of the evaluation sample after immersion in boiling water for 10 hours was evaluated in the same manner as the initial adhesion described above. (4) Pencil hardness was measured by applying a load of 750 g using the pencil scratch test described in JIS K5600-5-4. KBM403: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) KBE903: 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) MP200: Hydrolysis condensate of 3-glycidoxypropyltrimethoxysilane (manufactured by Momentive Performance Materials, CoatOSil MP200 silane) Eg-Pr: A composition containing a [3-(2,3-dihydroxyprop-1-oxy)propyl]silanol oligomer as described in Example 4 of JP-A-2017-114852 As shown in Table 2, Examples 3-1 and 3-2, in which the organopolysiloxanes Ep1 and Ep2 obtained in Examples 1-1 and 1-2 were used as primer components, exhibited excellent urethane coating film appearance, adhesion, and hardness. This result demonstrates the usefulness of the organopolysiloxanes of the present invention as adhesion-contributing components for environmentally friendly water-based coatings, not limited to primers but also showing potential for application as adhesion-enhancing agents added to coatings. On the other hand, Comparative Examples 3-1 and 3-3, in which 3-glycidoxypropyltrimethoxysilane and its hydrolyzed condensate were used as primer components, showed insufficient adhesion. Comparative Example 3-2, a primer component containing amino groups highly reactive with urethane coatings, showed good adhesion improvement, but showed a tendency toward excessive reactivity, significantly impairing the urethane coating's coatability and compromising the coating film's appearance. Comparative Example 3-4 had poor adhesion due to insufficient reactivity of the ethylene glycol structural group with the urethane coating. [Figure 1] is the organopolysiloxane Ep1 obtained in Example 1-1 1 H-NMR spectrum.

Claims

1. An organopolysiloxane as shown in formula (1) below, (where R1 is a monovalent hydrocarbon group with 1 to 10 carbon atoms, R2 is a monovalent hydrocarbon group with 1 to 10 carbon atoms that can be substituted by epoxypropoxy groups, R3 is a monovalent saturated hydrocarbon group with 1 to 6 carbon atoms, but at least a portion of R3 is a monovalent saturated hydrocarbon group with 3 to 6 carbon atoms, a, b, c, d are numbers that satisfy a≧0.5, b≧0, c≧0, d≧0 and a+b+c+d=1, and x, y are numbers that satisfy x≧1 and 0<y≦0.5).

2. The organopolysiloxane as claimed in claim 1, wherein R 3 is a monovalent saturated hydrocarbon group having 3 or 4 carbon atoms.

3. The organic polysiloxane as requested in item 1 or 2, wherein b, c, d, and y are numbers that satisfy b=0, c=0, d=0, and 0.01≦y≦0.

1.

4. A method for manufacturing an organopolysiloxane, comprising a method for manufacturing an organopolysiloxane as claimed in any one of claims 1 to 3, wherein a silica monomer comprising one or more of the following: a silica compound containing a 3-epoxypropoxypropyl group as shown in formula (i), a silica compound as needed as shown in formula (ii), a silica compound as shown in formula (iii), and a silica compound as shown in formula (iv), is subjected to a (co)hydrolysis-condensation reaction of the silica monomer in the presence of an alcohol as shown in formula (v), with 0.8 to 1.1 times the amount of water added relative to 1 mole of the Si(OR) group (R being a monovalent saturated hydrocarbon group having 1 to 6 carbon atoms) of the silica monomer, and the reaction is carried out under acidic conditions; (wherein, R1, R2, and R are the same as above, and R0 is a monovalent saturated hydrocarbon group having 3 to 6 carbon atoms).

5. A bonding agent comprising an organopolysiloxane as claimed in any one of claims 1 to 3.

6. A water-based coating composition comprising an organopolysiloxane as claimed in any one of claims 1 to 3.

7. A primer composition comprising an organopolysiloxane as claimed in any one of claims 1 to 3.

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