Aqueous binder for anti-rust paint, anti-rust paint composition, and method for producing aqueous binder for anti-rust paint

Abstract

To provide an aqueous binder for anti-rust paint, an anti-rust paint composition, and a method for producing an aqueous binder for anti-rust paint, which can provide an anti-rust paint film with low adhesion in an anti-rust treatment step and high corrosion resistance. The aqueous binder for anticorrosive paint is obtained by hydrolysis and polycondensation of at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent, wherein the first organosilicon compound (A) and the second organosilicon compound (B) are each at least one selected from a group consisting of specific compounds, the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B) is greater than 0 and 0.2 or less, and the weight-average molecular weight (as PEG) of the aqueous binder for anticorrosive paint is 0.6 x 10 3 Over 1.5 x 10 3 The following is a water-based binder for anti-rust paint.

Description

[Technical Field]

[0001] The present invention relates to an aqueous binder for anticorrosive paint, an anticorrosive paint composition, and a method for producing an aqueous binder for anticorrosive paint. [Background technology]

[0002] Water-based anti-corrosion paints use inorganic binders or organic-inorganic hybrid binders that have affinity with anti-corrosion pigments and metal substrates. These binders contribute to the dispersion stability of metal pigments in the paint and are expected to contribute to the adhesion to the substrate and the mechanical properties of the coating film after the paint is applied to the substrate and dried and / or heat-treated. For example, inorganic binders and organic-inorganic hybrid binders used in water-based anti-corrosion paints are synthesized by sol-gel reactions using tetrafunctional metal alkoxides and / or silane coupling agents as raw materials.

[0003] Patent Document 1 discloses an aqueous adhesive composition containing a styrene-butadiene-acrylic copolymer latex and an aqueous solution of a silane coupling agent hydrolysate, wherein the styrene-butadiene-acrylic copolymer latex is a styrene-butadiene-acrylic copolymer latex having a mass ratio of styrene-butadiene moieties to acrylic moieties of styrene-butadiene moieties / acrylic moieties = 90 / 10 to 70 / 30, and the aqueous solution of silane coupling agent hydrolysate is an aqueous solution of silane coupling agent hydrolysate in which the concentration of the silane coupling agent in the aqueous solution is 10 mass % or less, assuming that the silane coupling agent in the aqueous solution is not subjected to hydrolysis, and the aqueous adhesive composition contains 0.5 to 15 mass parts of the aqueous solution of silane coupling agent hydrolysate per 100 mass parts of the resin solids content of the styrene-butadiene-acrylic copolymer latex.

[0004] Patent Document 2 discloses a coating composition containing (A) an epoxy silane oligomer having an epoxy group and a siloxane bond and a weight average molecular weight of 500 to 20,000, (B) colloidal silica having an average primary particle size in the range of 1 to 100 nm, and (C) a curing catalyst. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-026502 [Patent Document 2] International Publication No. 2018 / 151271 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned conventional techniques leave room for improvement in terms of suppressing adhesion of the coating film obtained by the anti-rust paint and in terms of the corrosion resistance of the coating film.

[0007] For example, in the case of inorganic binders or organic-inorganic hybrid binders synthesized by a sol-gel reaction using tetrafunctional metal alkoxides and / or silane coupling agents as raw materials, it has been found that in coating films obtained using anti-rust paints that use binders with a low ratio of silane coupling agent and a high ratio of tetrafunctional metal alkoxide, the hydroxyl group density of the binder is high, which tends to increase the adhesion between coating films on anti-rust treated products. In particular, when applying anti-rust treatment to components with many flat surfaces, the adhesion between coating films on the components tends to increase during the heat treatment process, significantly reducing workability and causing particular problems.

[0008] On the other hand, in anti-rust paints that use inorganic binders or organic-inorganic hybrid binders with a high ratio of silane coupling agent and a low ratio of tetrafunctional metal alkoxide, the polarity of the binder decreases as the organic functional groups increase, which tends to weaken the adhesion between the coating films on anti-rust treated products, but because the molecular weight is small, the corrosion resistance of the anti-rust coating tends to be insufficient.

[0009] Furthermore, even in the prior art including Patent Documents 1 and 2, it is difficult to obtain an anti-rust coating film that can achieve both high levels of suppression of adhesion of the coating film obtained by the anti-rust paint and high levels of corrosion resistance of the coating film, and there is currently a demand for improvements in aqueous binders for anti-rust paints.

[0010] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an aqueous binder for anti-rust paint, an anti-rust paint composition, and a method for producing an aqueous binder for anti-rust paint, which can reduce the adhesion of the coating film during the anti-rust treatment step and can provide an anti-rust coating film having high corrosion resistance. [Means for solving the problem]

[0011] As a result of intensive research by the present inventors to solve the above-mentioned problems, they have found an aqueous binder for anticorrosive paints obtainable by hydrolyzing and polycondensing at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent, wherein the first organosilicon compound (A) is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane, and the second organosilicon compound (B) is at least one selected from the group consisting of tetramethyl silicate and tetraethyl silicate, and the molar fraction of the number of moles of the second organosilicon compound (B) to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B) is greater than 0 and not greater than 0.2, and the weight average molecular weight (as PEG) of the aqueous binder for anticorrosive paints is 0.6×10 3 Over 1.5 x 10 3The present invention has been accomplished based on the findings of the following aqueous binder for anticorrosive paint.

[0012] (1) An aqueous binder for anticorrosive paint obtained by hydrolysis and polycondensation of at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent, wherein the first organosilicon compound (A) is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane, and the second organosilicon compound (B) is at least one selected from the group consisting of tetramethyl silicate and tetraethyl silicate, and the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B) is greater than 0 and not greater than 0.2, and the weight average molecular weight (as PEG) of the aqueous binder for anticorrosive paint is 0.6×10 3 Over 1.5 x 10 3 The following is a water-based binder for anti-rust paint. (2) An anti-rust paint composition containing the aqueous binder for anti-rust paint described in (1) above. (3) A method for producing an aqueous binder for an anticorrosive paint, comprising a reaction step of hydrolyzing and polycondensing at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent to obtain an aqueous binder for an anticorrosive paint, wherein the first organosilicon compound (A) is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane, and the second organosilicon compound (B) is tetramethylsilane. and at least one selected from the group consisting of silicate and tetraethyl silicate, the reaction step being a step of hydrolyzing and polycondensing the first organosilicon compound (A) and the second organosilicon compound (B) in an aqueous solvent, with the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B) being greater than 0 and not greater than 0.2, and the weight average molecular weight (as PEG) of the aqueous binder for anticorrosive paint being 0.6×10 3 Over 1.5 x 10 3 The following is a method for producing an aqueous binder for anti-rust paint. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an aqueous binder for anti-rust paint, an anti-rust paint composition, and a method for producing an aqueous binder for anti-rust paint, which can reduce adhesion of the coating film during the anti-rust treatment step and can provide an anti-rust coating film having high corrosion resistance. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present embodiment can be appropriately modified and carried out within the scope of its gist.

[0015] In the numerical ranges described in this embodiment in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this embodiment, the upper or lower limit value of the numerical range may be replaced with the value shown in the examples.

[0016] <Water-based binder for anti-rust paint> The aqueous binder for anticorrosive paint according to this embodiment is an aqueous binder for anticorrosive paint obtained by hydrolyzing and polycondensing at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent, wherein the first organosilicon compound (A) is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane, the second organosilicon compound (B) is at least one selected from the group consisting of tetramethyl silicate and tetraethyl silicate, the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B) is greater than 0 and not greater than 0.2, and the weight average molecular weight (as PEG) of the aqueous binder for anticorrosive paint is 0.6×10 3 Over 1.5 x 10 3 The following is a water-based binder for anti-rust paint.

[0017] (organosilicon compounds) The first organosilicon compound (A) in this embodiment is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane. The first organosilicon compound (A) may be, for example, a compound known as a silane coupling agent.

[0018] In this embodiment, the second organosilicon compound (B) is at least one selected from the group consisting of tetramethyl silicate and tetraethyl silicate. The second organosilicon compound (B) may be, for example, a compound known as a tetrafunctional silicon alkoxide.

[0019] The aqueous binder for anticorrosive paint according to this embodiment can be obtained by hydrolyzing and polycondensing at least one of the first organosilicon compounds (A) and at least one of the second organosilicon compounds (B) described above in an aqueous solvent.

[0020] (Other organosilicon compounds) The aqueous binder for anticorrosive paint according to this embodiment may be obtained by hydrolysis and polycondensation of at least the first organosilicon compound (A) and the second organosilicon compound (B). However, other monomers besides components (A) and (B) may also be subjected to the reaction (e.g., hydrolysis and polycondensation). For example, in addition to the organosilicon compounds of components (A) and (B), an organosilicon compound (C) other than components (A) and (B) may also be used in combination. The other organosilicon compound (C) may be any compound capable of polycondensation with components (A) and / or (B). The type of the other organosilicon compound (C) is not limited, and examples thereof include silane coupling agents other than components (A) and (B) and tetrafunctional silicon alkoxides other than components (A) and (B).

[0021] Examples of silane coupling agents other than component (A) and component (B) include silane coupling agents having an epoxy group and an alkoxy group having 3 or more carbon atoms. Examples of silane coupling agents having an epoxy group and an alkoxy group having 3 or more carbon atoms include [3-(2,3-epoxypropoxy)propyl]triisopropoxysilane and [3-(2,3-epoxypropoxy)propyl]tributoxysilane.

[0022] Examples of tetrafunctional silicon alkoxides other than components (A) and (B) include tetrafunctional silicon alkoxides in which the alkoxy group has 3 or more carbon atoms. Examples of tetrafunctional silicon alkoxides in which the alkoxy group has 3 or more carbon atoms include tetraisopropyl silicate and tetrabutyl silicate.

[0023] (The mole fraction of the number of moles of component (B) relative to the total number of moles of component (A) and component (B)) In this embodiment, the molar fraction ((B) / ((A)+(B)) of the number of moles of the second organosilicon compound (B) relative to the sum (total number of moles) of the number of moles of the first organosilicon compound (A) and the number of moles of the second organosilicon compound (B) is greater than 0 and not greater than 0.2. The lower limit of this molar fraction is preferably 0.05 or greater. The upper limit of this molar fraction is preferably 0.15 or less, more preferably 0.12 or less, and even more preferably 0.10 or less. When the molar fraction ((B) / ((A)+(B)) is equal to or greater than the above-mentioned lower limit, it is possible to more effectively suppress the sticking of the rust-preventive coating film, and it is expected that, for example, the throughput of the coating process will be further improved. When the molar fraction ((B) / ((A)+(B))) is equal to or less than the above-mentioned upper limit, it is expected that the corrosion resistance of the rust-preventive coating film will be further improved. Note that when the molar fraction ((B) / ((A)+(B))) is greater than 0.2, it tends to be particularly difficult to suppress the sticking of the rust-preventive coating film.

[0024] (aqueous solvent) The aqueous solvent used in the hydrolysis reaction and the polycondensation reaction preferably contains water and / or a hydrophilic organic solvent. The aqueous solvent may be water alone, a hydrophilic organic solvent alone, or a mixed aqueous solvent containing water and a hydrophilic organic solvent.

[0025] Specific examples of hydrophilic organic solvents include 1,4-dioxane, acetone, methyl ethyl ketone, cyclohexanone, γ-butyrolactone, methyl acetate, ethyl acetate, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, ethylene glycol mono-n-butyl ether, 2-(2-hydroxypropoxy)-1-propanol, 1-(2-hydroxypropoxy)-2-propanol, 2-(2-hydroxy-1-methylethoxy)-1-propanol, 2,2′-[1,2-ethanediylbis(oxy)]bisethanol, etc. Among these, 1-(2-hydroxypropoxy)-2-propanol, 2-(2-hydroxypropoxy)-1-propanol, and 2-(2-hydroxy-1-methylethoxy)-1-propanol are preferred.

[0026] The hydrophilic organic solvent may be used alone or in combination of two or more kinds.

[0027] From the viewpoint of more effectively suppressing inhibition of the hydrolysis reaction, the ratio (mass ratio) of the content of the hydrophilic organic solvent to the total amount of the aqueous solvent is preferably 0 mass % or more and 30 mass % or less, and more preferably 0 mass % or more and 20 mass % or less.

[0028] The boiling point of the hydrophilic organic solvent is not particularly limited, but is preferably 180°C or higher and 285°C or lower. The lower limit of the boiling point is more preferably 195°C or higher, and even more preferably 200°C or higher. The upper limit of the boiling point is more preferably 245°C or lower, and even more preferably 235°C or lower. By using a hydrophilic organic solvent having such a boiling point, the storage stability of the water-based anticorrosive coating material can be improved.

[0029] Furthermore, it is more preferable that the hydrophilic organic solvent contains a polyhydric alcohol having the above-mentioned boiling point. For example, if the boiling point is equal to or higher than the above-mentioned lower limit, the hydrolysis reaction and polycondensation reaction of the organosilicon compound can be easily controlled. Furthermore, if the boiling point is equal to or lower than the above-mentioned upper limit, the solvent can be removed without high-temperature treatment in the drying step, which is preferable (although the functions and effects of this embodiment are not limited thereto). Examples of polyhydric alcohols include 2-(2-hydroxypropoxy)-1-propanol, 1-(2-hydroxypropoxy)-2-propanol, 2-(2-hydroxy-1-methylethoxy)-1-propanol, 2,2'-[1,2-ethanediylbis(oxy)]bisethanol, and 2,2'-oxydiethanol. Among these, 2-(2-hydroxypropoxy)-1-propanol, 1-(2-hydroxypropoxy)-2-propanol, and 2-(2-hydroxy-1-methylethoxy)-1-propanol are preferred.

[0030] (Ratio of water / organosilicon compound content) In this embodiment, the content of water contained in the aqueous solvent during hydrolysis and polycondensation in the aqueous solvent is preferably 10 times or more the theoretical amount required for hydrolyzing the first organosilicon compound (A) and the second organosilicon compound (B). However, the lower limit of the ratio (mass ratio) of the content of water contained in the aqueous solvent to the total content of the first organosilicon compound (A) and the second organosilicon compound (B) is preferably 6 or more, from the viewpoint of completely hydrolyzing the organosilicon compounds. Furthermore, the upper limit of this content ratio is preferably 12 or less, from the viewpoint of reducing the molecular weight of the hydrolysis polycondensate. Therefore, an example of a preferred combination is a content ratio of 6 or more and 12 or less.

[0031] (acids, bases) In the aqueous binder for anticorrosive coating according to this embodiment, the pH may be adjusted by adding an acid or a base in order to more effectively control the hydrolysis and polycondensation described above. However, the reaction may proceed without adding an acid or a base due to the autocatalytic action of the hydroxyl groups generated by the hydrolysis (however, the functions and effects of this embodiment are not limited to these).

[0032] The acid to be added is not particularly limited, but examples thereof include nitric acid, hydrochloric acid, phosphoric acid, acetic acid, oxalic acid, succinic acid, boric acid, etc. The base to be added is not particularly limited, but examples thereof include aqueous ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. The amounts of acid and base to be added are not particularly limited, and can be selected appropriately depending on the type of organosilicon compound used and the pH control conditions.

[0033] (Weight average molecular weight) The weight average molecular weight (polyethylene glycol (PEG) equivalent) of the aqueous binder for anticorrosive paint according to this embodiment is 0.6 × 10 3 Over 1.5 x 10 3 The weight average molecular weight of the water-based binder for anti-rust paint is 0.6 × 10 or less. 3 If the weight average molecular weight of the water-based binder for anti-rust paint is less than 1.5 × 10, good adhesion tends to be difficult to obtain. 3 If the weight average molecular weight is larger than 0.7 × 10, high corrosiveness tends not to be obtained. 3 It is preferable that the value is equal to or greater than 1.0×10 3 More preferably, it is equal to or greater than this.

[0034] The weight average molecular weight is defined as a polyethylene glycol equivalent value measured by GPC (Gel Permeation Chromatography) using a GPC device. The GPC measurement conditions are as follows. Detector: Differential refractive index detector Eluent: 0.20mol / L NaNO3aq Columns: TSKgel G3000PWXL x 3, TSKgel G2500PWXL x 1 Column temperature: 40℃ Sample concentration: 0.2% (w / v) Flow rate: 1.000mL / min Injection volume: 10μL Calibration curve: PEO / PEG

[0035] <Manufacturing method for water-based binders for anti-rust paints> The method for producing an aqueous binder for an anticorrosive paint according to this embodiment is a method for producing an aqueous binder for an anticorrosive paint, comprising a reaction step of hydrolyzing and polycondensing at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent to obtain the aqueous binder for an anticorrosive paint, the first organosilicon compound (A) is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane; the second organosilicon compound (B) is at least one selected from the group consisting of tetramethyl silicate and tetraethyl silicate; The reaction step is a step of hydrolyzing and polycondensing the first organosilicon compound (A) and the second organosilicon compound (B) in an aqueous solvent, wherein the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B) is greater than 0 and not more than 0.2; The weight average molecular weight (PEG equivalent) of the water-based binder for anti-rust paint is 0.6 x 10 3 Over 1.5 x 10 3 The following is an example of a method for producing an aqueous binder for anticorrosive paint. The first organosilicon compound (A), the second organosilicon compound (B), the aqueous solvent, the conditions for hydrolysis and polycondensation, and various other conditions can be appropriately selected from the above-mentioned contents and conditions.

[0036] A suitable example of the method for producing the aqueous binder for anticorrosive paint according to this embodiment is to add the first organosilicon compound (A) and the second organosilicon compound (B) to an aqueous solvent under stirring over a period of 0.2 to 0.5 hours, and carry out a reaction step including a hydrolysis reaction and a polycondensation reaction. It is preferable to control the reaction temperature in the reaction step so that the temperature of the reaction solution is 25°C to 35°C.

[0037] Furthermore, it is preferable to further include a heating step after the reaction step, in which the reaction product of the reaction step is heated at 35° C. to 40° C. In this heating step, for example, after the addition of the first organosilicon compound (A) and the second organosilicon compound (B) is completed, the reaction solution is heated at 35° C. to 40° C. for preferably 2 hours or more, more preferably 4 hours or more, and even more preferably 6 hours or more. The heating step can increase the weight average molecular weight of the binder.

[0038] Furthermore, it is preferable to further include an aging step after the reaction step, in which the reaction product of the reaction step is aged at 45° C. or higher and 55° C. or lower. Regarding this heating step, it is also preferable to carry out an aging step in which the reaction solution is aged in an incubator or the like at 45° C. or higher and 55° C. or lower for at least 5 days or more, more preferably 10 days or more, and even more preferably 20 days or more. The aging step can further increase the weight average molecular weight of the binder.

[0039] In the method for producing an aqueous binder for an anticorrosive paint according to this embodiment, at least one of a heating step and an aging step may be performed, or both of these steps may be performed. However, from the viewpoint of reaction control, etc., it is preferable to perform both the heating step and the aging step.

[0040] <Anti-rust paint composition> The aqueous binder for anticorrosive paint according to the present embodiment described above can be suitably used as an anticorrosive paint composition. Suitable examples of the anticorrosive paint composition according to the present embodiment include those containing the aqueous binder for anticorrosive paint described above.

[0041] (solvent) The anti-rust coating composition according to this embodiment may contain a solvent. This solvent is preferably an aqueous solvent. The aqueous solvent preferably contains water and / or a hydrophilic organic solvent. The aqueous solvent may be water alone, a hydrophilic organic solvent alone, or a mixed aqueous solvent containing water and a hydrophilic organic solvent. The organic solvent component contained in the anti-rust coating composition may be a hydrophilic organic solvent used in the production of a binder for aqueous paints, and some or all of the by-produced alcohol, but organic solvents of the same or different types as these may also be added.

[0042] The organic solvent used in the anticorrosive coating composition according to this embodiment is preferably a hydrophilic organic solvent. Examples of hydrophilic organic solvents include ethane-1,2-diol, 2,2'-oxydiethanol, 2,2'-(1,2-ethanediylbis(oxy))bisethanol, 2,2'-[oxybis(ethane-2,1-diyloxy)]diethanol, 2-(2-hydroxypropoxy)-1-propanol, 1-(2-hydroxypropoxy)-2-propanol, 2-(2-hydroxy-1-methylethoxy)-1-propanol, 2-[2-(2-hydroxypropoxy)-1-methylethoxy]propanol, 2-[2-(2-hydroxy-1 Examples of the glycol ethers include 2-[2-(2-hydroxyethoxy)ethoxy]propanol, 2-[2-(2-hydroxyethoxy)propoxy]propanol, 2-[2-(2-hydroxyethoxy)ethoxy]ethanol, and 2-[2-[2-(2-hydroxyethoxy)ethoxy]ethoxy]ethanol; glycol ethers such as monomethyl ethers, monoethyl ethers, dimethyl ethers, and diethyl ethers of these glycols; alcohols such as ethanol, propanol, and isopropanol; and ketones such as acetone and methyl ethyl ketone. Among these, glycols and glycol ethers are preferred.

[0043] The organic solvent may be used alone or in combination of two or more kinds.

[0044] The content of the aqueous solvent (water and / or organic solvent) in the anticorrosive coating composition according to this embodiment is not particularly limited, but is preferably 30% by mass or more, more preferably 35% by mass or more. The upper limit of this content is preferably 85% by mass or less. A preferred range of the content is, for example, 30% by mass or more and 85% by mass or less.

[0045] When the aqueous solvent is a mixed aqueous solvent containing water and an organic solvent, the content of water in the total amount of the mixed aqueous solvent is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and even more preferably 100% by mass (water only).

[0046] (Anti-rust pigment) The anti-rust coating composition according to this embodiment may further contain an anti-rust pigment. The anti-rust pigment is not particularly limited, but it is generally preferable to use a metal that has a greater ionization tendency than the base metal. For example, when the object to be anti-rust contains iron, zinc or zinc alloy particles (hereinafter sometimes collectively referred to as "zinc-based particles") can be used. The zinc-based particles may be used alone or as a mixture of two or more types. In addition to the zinc-based particles, aluminum or aluminum alloy particles (hereinafter sometimes collectively referred to as "aluminum-based particles") can also be used. The aluminum-based particles may be used in combination with the zinc-based particles described above.

[0047] The type of zinc alloy is not particularly limited, and any alloy containing zinc may be used, such as an alloy containing zinc and at least one selected from the group consisting of magnesium, aluminum, nickel, manganese, cobalt, tin, and chromium. Among these, zinc-based particles are preferably zinc particles and particles of an alloy containing zinc and aluminum (Zn-Al alloy). In the case of a zinc alloy containing zinc and other metal atoms, the zinc content in the zinc alloy is not particularly limited, but is preferably 50% by mass or more, and more preferably 55% by mass or more.

[0048] The form of zinc-based particles is not particularly limited, and can be used in the form of powder or paste, for example.The shape of zinc-based particles is also not particularly limited, and can be, for example, approximately spherical, flake-like, scale-like, thin plate-like, lamellar, etc., but usually, flake-like is preferred.In addition, two or more types of zinc-based particles with different shapes can also be used in combination.

[0049] For example, when the zinc-based particles are flake-shaped, although not particularly limited, their average major axis is preferably 2 μm to 50 μm, more preferably 3 μm to 30 μm. The average particle thickness is preferably 0.2 μm to 5 μm, more preferably 0.3 μm to 2 μm. The average particle aspect ratio (major axis / thickness) is preferably in the range of 10 to 500, more preferably 10 to 100. Two or more types of zinc-based particles with different average aspect ratios (major axis / thickness) can also be used in combination.

[0050] When the zinc-based particles are in the form of flakes, the BET specific surface area is, but is not particularly limited to, 0.1 m 2 / g or more 10m 2 / g or less, and 0.5m 2 / g or more 5m 2 / g or less is more preferable, and 1m 2 / g or more 3m 2 It is more preferable that the saturation coefficient is 1 / g or less.

[0051] The zinc-based particles may be particles with an untreated surface (unmodified, surface-untreated particles), or may be particles (surface-treated particles) with at least a portion, preferably the entire surface, treated with boric acid, phosphoric acid, a silane coupling agent, vanadate, niobate, molybdate, tungstate, or the like.

[0052] The content of the anti-rust pigment in the anti-rust coating composition according to this embodiment is not particularly limited, but is preferably 10% by mass or more and 60% by mass or less. When the anti-rust pigment contains zinc-based particles and aluminum-based particles, the ratio (mass ratio) of the content of the zinc-based particles to the content of the aluminum-based particles is preferably 9:1 to 5:5.

[0053] (additives) The anticorrosive coating composition according to this embodiment may contain various additives commonly used in coatings, such as surfactants, metal oxide pigments, organic pigments, thickeners, repair agents, etc., as needed.

[0054] (surfactant) By including a surfactant in the anticorrosive coating composition according to this embodiment, the adhesion and leveling properties of the resulting anticorrosive coating film can sometimes be improved.

[0055] The surfactant is not particularly limited, and examples thereof include nonionic surfactants, cationic surfactants, and anionic surfactants. Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkylamides, polyoxyethylene higher alcohol ethers, polyoxyalkylene alkyl ethers, polyoxyethylene polyoxypropylene glycols, polyethylene glycol fatty acid esters, glycerin fatty acid esters, propylene glycol fatty acid esters, alkyl glyceryl ethers, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters. Examples of cationic surfactants include mono-, di-, or trialkylamine salts, alkyltrimethylammonium halides, dialkyldimethylammonium halides, and alkyldimethylbenzylammonium chloride. Examples of anionic surfactants include mono- or dialkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, and dialkyl sulfosuccinates. Among these, nonionic surfactants are preferred. Surfactants may be used alone or in combination of two or more. When two or more surfactants are used in combination, the total amount of these surfactants is the content in the anticorrosive coating composition according to this embodiment.

[0056] The content of the surfactant in the anticorrosive coating composition according to this embodiment is not particularly limited, but is preferably 0.01% by mass or more and 10% by mass or less.

[0057] (hydrophilic organic binder) The anticorrosive coating composition according to this embodiment may further contain a hydrophilic organic binder (hydrophilic organic binder) in addition to the aqueous binder for the anticorrosive coating according to this embodiment in order to improve the mechanical properties of the anticorrosive coating film.

[0058] The hydrophilic organic binder is not particularly limited, but examples thereof include phenol resin, methylolated urea resin, methylolated melamine resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyethylene oxide, polyacrylamide resin, carboxymethyl cellulose resin, etc. Among these, phenol resin and polyvinyl acetal resin are preferred.

[0059] (other pigments) The anti-rust coating composition according to this embodiment may further contain other pigments, such as metal oxide pigments and organic pigments, in addition to the anti-rust pigment. The metal oxide pigments and organic pigments may also have anti-rust properties.

[0060] The metal oxide pigment is not particularly limited, but examples thereof include manganese oxide particles, molybdenum oxide particles, tungsten oxide particles, tin oxide particles, antimony oxide particles, iron oxide particles, aluminum oxide particles, zinc oxide particles, magnesium oxide particles, niobium oxide particles, vanadium oxide particles, tantalum oxide particles, silica particles, titania particles, zirconia particles, silica alumina particles, silica titania particles, silica magnesia particles, etc. Among these, molybdenum oxide and vanadium oxide are preferred.

[0061] The organic pigment is not particularly limited, but examples thereof include β-naphthol-based pigments, β-oxynaphthoic pigments, pyrazolone-based pigments, acetoacetate arylide-based monoazo pigments, acetoacetate arylide-based disazo pigments, benzimidazolone-based monoazo pigments, isoindolinone-based pigments, styrene-based pigments, isoindoline-based pigments, and phthalocyanine-based pigments.

[0062] (thickener) The anticorrosive coating composition according to this embodiment may contain a thickener for the purpose of adjusting the viscosity.

[0063] The thickener is not particularly limited, but examples thereof include ethers (cellulose ethers) such as methyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, ethylhydroxyethyl cellulose, methyl ethyl cellulose, and hydroxypropyl cellulose, cellulose-based thickeners such as cellulose nanofibers, xanthan gum, urethane-based thickeners, acrylic-based thickeners, denatured clay, fatty acid salts, and fatty acid amides. Among these, cellulose ethers and xanthan gum are preferred as the thickeners used. One type of thickener may be used alone, or two or more types may be used in combination. When two or more types of thickeners are used in combination, the total amount thereof is the content in the anticorrosive coating composition according to this embodiment.

[0064] The content of the thickener in the anticorrosive coating composition according to this embodiment is not particularly limited, but is preferably 0.005% by mass or more and 2% by mass or less.

[0065] (repair agent) The repair agent (inhibitor) that can be added to the anti-rust coating composition of this embodiment is preferably a compound that can react with the exposed metal or alloy surface to form a coating film or modify the surface (repair) when the anti-rust pigment of this embodiment or other metal pigment is damaged in the composition, exposing the metal or alloy surface.

[0066] The repair agent is not particularly limited, but examples thereof include boron compounds such as boric acid, aluminum compounds such as aluminum hydroxide, gallium compounds such as gallium hydroxide, silicon compounds such as sodium silicate, indium compounds such as indium hydroxide, tin compounds such as tin hydroxide, bismuth compounds such as bismuth hydroxide, vanadate compounds such as lithium vanadate, tungstate compounds such as lithium tungstate, molybdate compounds such as potassium molybdate, cerium compounds such as cerium nitrate, phosphates such as potassium phosphate, amine compounds such as polyethyleneimine, and silicon compounds such as tetraethyl silicate. Phosphates and bismuth compounds are preferred repair agents. One repair agent may be used alone, or two or more may be used in combination. Furthermore, the repair agent may be added in the form of an anti-rust pigment containing the compound, or the compound impregnated or supported on zeolite or cellulose nanofiber, or the compound encapsulated within. The addition method is not particularly limited.

[0067] (Other additives) In addition, conventional paint additives such as dispersants, lubricants, wetting agents, leveling agents, surface conditioners, rheology modifiers, pH adjusters, pH stabilizers, film-forming aids, stabilizers, thixotropes, antifoaming agents, ultraviolet absorbers, flame retardants, preservatives, antistatic agents, and colorants may also be incorporated into the anticorrosive paint composition of this embodiment.

[0068] (Method of manufacturing anti-rust coating composition) The anti-rust coating composition according to this embodiment can be produced by uniformly stirring and / or mixing the anti-rust pigment, the binder according to this embodiment, water, an organic solvent, additives, and the like, using a commonly used known method.

[0069] (Anti-rust coatings and articles with anti-rust coatings) The rust-preventive coating film of this embodiment can be obtained by applying the above-described rust-preventive coating composition of this embodiment to a substrate or the like, followed by drying and / or heat treatment.

[0070] The obtained anti-rust coating film may be further subjected to a heat treatment.

[0071] In this specification, the removal of the solvent component from the anticorrosive coating composition is sometimes referred to as "drying." Furthermore, the curing of the coating film after drying is sometimes referred to as "heat treatment." However, the coating film may also be cured during drying, and the solvent component may also be removed from the anticorrosive coating composition during heat treatment.

[0072] An article having the rust-preventive coating film of this embodiment has a rust-preventive coating film on its surface that is obtained by applying the above-described rust-preventive paint composition of this embodiment to a substrate, followed by drying and / or heat treatment. For example, the article can be obtained by applying the rust-preventive paint composition of this embodiment to an object to be coated, followed by drying and / or heat treatment.

[0073] (Metallic or alloy materials to which anti-rust paint compositions can be applied) The metal or alloy material to which the anticorrosive coating composition according to the present embodiment can be applied is not particularly limited, and examples thereof include aluminum, aluminum alloys, iron, iron alloys, carbon steel, alloy steel, and stainless steel. Furthermore, the composition can also be applied to metal or alloy surfaces that have been subjected to surface treatments such as plating, chemical conversion treatment, anodizing, nitriding, carbonization, or dry plating. In particular, the composition is particularly suitable for applications where the substrate contains iron or an iron alloy, or has a film or layer containing iron or an iron alloy on its surface, since excellent corrosion resistance can be achieved. The coating target or substrate may be a raw material (the metal or alloy material itself), an intermediate product, a final product, or the like, and is not particularly limited.

[0074] (Method for applying anti-rust coating composition) The method for applying the anticorrosive coating composition according to this embodiment to the substrate is not particularly limited and can be any known method, but is preferably, for example, a dipping method (immersion method), a dip spin method (immersion method accompanied by centrifugal shaking), a spray coating method, a spin coating method, etc. Alternatively, the composition can be applied using a roller, a doctor blade, a bar coater, a brush, etc. The application conditions are also not particularly limited and can be selected appropriately.

[0075] The anticorrosive coating composition according to this embodiment is applied to an object to be coated, and then dried and / or heat-treated to form the anticorrosive coating film according to this embodiment. After drying at a relatively low temperature, heat treatment at a higher temperature may be performed.

[0076] The drying or heat treatment method is not particularly limited and can be selected as appropriate. It is usually preferable to heat the anticorrosive coating composition applied to the substrate to a temperature in the range of 60°C to 400°C to remove the solvent and form an anticorrosive coating film. The heating method is not particularly limited and can be any known method such as convection heating, infrared heating, or induction heating. The heat treatment conditions, such as the heat treatment time and heat treatment atmosphere, are also not particularly limited and can be selected as appropriate. For example, the heat treatment may be performed in air or in an inert gas such as nitrogen gas.

[0077] Before applying the anti-corrosion coating composition according to this embodiment to an object to be coated, the object may be subjected to degreasing and / or water washing, etc., as necessary. Such degreasing and / or water washing can be carried out by a known method. For example, the degreasing and / or water washing can be carried out by appropriately selecting from solvent degreasing using a hydrocarbon-based degreasing agent or the like, water washing using an alkaline aqueous degreasing agent or the like, cleaning using supercritical CO2 or the like, and the like.

[0078] The amount of the anticorrosive coating composition according to this embodiment to be applied is not particularly limited, but in general, the average thickness of the anticorrosive coating film after drying is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 30 μm or less. In addition, the amount of zinc in the anticorrosive coating film after drying is 3 g / m 2 More than 200g / m2 Preferably, it is 20 g / m or less. 2 More than 120g / m 2 More preferably, it is:

[0079] (stickiness) The adhesion of the coating film obtained by the anticorrosive coating composition according to this embodiment is such that the adhesion rate is 30% or less in an adhesion test. Details of the adhesion test are described in the Examples. [Example]

[0080] The present invention will be explained in more detail with reference to the following examples and comparative examples, but the scope of the present invention is not limited by these examples in any sense.

[0081] Example 1 <Production of binder solution> (Hydrolysis and Polycondensation) To 170 parts by weight of ion-exchanged water, 14.3 parts by weight of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane (molecular weight 236.34) as the first organosilicon compound (A) and 0.7 parts by weight of tetraethyl silicate (molecular weight 208.33) as the second organosilicon compound (B) were added over 0.5 hours to carry out hydrolysis and polycondensation reactions. When adding [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and tetraethyl silicate to the ion-exchanged water, the temperature of the reaction solution was controlled to remain below 35°C. After the addition was complete, the mixture was heated at a temperature between 35°C and 40°C for 6 hours, then placed in a container equipped with a gas vent valve and heated in an incubator at 50°C for 10 days to obtain a crude binder solution.

[0082] (density adjustment) The crude binder solution was distilled using a rotary evaporator until the heating residue of the binder solution was 25% by mass or more. The evaporated solution was adjusted to a heating residue of 25% by mass by adding ion-exchanged water as needed, to obtain the target binder solution. The binder solution was stored in an incubator at 0°C.

[0083] The heating residue of the binder solution was determined by measuring the heating residue (in accordance with JIS K 5601_1_2). Furthermore, as a result of GPC measurement under the GPC measurement conditions shown below, the weight average molecular weight of the binder was found to be 0.6 × 10 3 In addition, in the hydrolysis and polycondensation, the content ratio of water (ion-exchanged water) to the first organosilicon compound (A) and the second organosilicon compound (B) (water / ((A)+(B)), mass ratio) was 11.3.

[0084] (GPC conditions) Detector: Differential refractive index detector Eluent: 0.20mol / L NaNO3aq Columns: TSKgel G3000PWXL x 3, TSKgel G2500PWXL x 1 Column temperature: 40℃ Sample concentration: 0.2w / v% Flow rate: 1.000mL / min Injection volume: 10μL Calibration curve: PEO / PEG

[0085] <Preparation of pigment solution> A pigment solution was prepared by uniformly mixing the following components using a high-speed disperser (Homodisper 2.5 model manufactured by Primix Corporation). Zinc flakes ("Zinc flakes MA-ZA-F" manufactured by Mitsui Mining & Smelting Co., Ltd.): 60 parts by mass Aluminum flakes ("WXM5660" manufactured by Toyo Aluminum Co., Ltd.): 10 parts by mass [3-(2,3-epoxypropoxy)propyl]trimethoxysilane: 10 parts by mass 2,2'-(1,2-ethanediylbis(oxy))bisethanol: 18 parts by mass Polyoxyethylene lauryl ether ("Emulgen 108" manufactured by Kao Corporation): 2 parts by mass

[0086] <Production of Anti-Rust Paint Composition> The following components were mixed uniformly using a high-speed disperser (Homodisper 2.5 model, manufactured by Primix Corporation) to prepare an anti-rust coating composition. Binder solution: 40 parts by mass Pigment solution: 59.8 parts by mass Xanthan gum (manufactured by Sansho Co., Ltd.) "KELZAN AR": 0.2 parts by weight The surfactant content in the anticorrosive coating composition obtained in Example 1 was 1.2 mass %.

[0087] <Evaluation of the anti-corrosion performance of coatings> The prepared coating composition was applied to an iron plate using a bar coater so that the dry film thickness was 8 μm, and then dried at 250° C. for 10 minutes to form a coating film. The iron plate on which the rust-preventive coating film was formed was then subjected to a salt spray test in accordance with JIS Z-2371 to evaluate the rust-preventive performance.

[0088] After 500 hours, almost no rust was observed on the steel plate coated with the prepared coating composition, with only a small amount of red rust being observed in the X-shaped cuts made after the coating was formed. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was observed in the X-shaped cuts made after the coating was formed.

[0089] <Evaluation of coating film adhesion> The adhesion test shown below was carried out, and the adhesion rate was 27%, which was acceptable.

[0090] (Adhesion test) An anti-rust coating composition was applied to the washer and bolt of an M6 identical washer-equipped bolt, and then dried at 100°C for 10 minutes to form an anti-rust coating film on the surfaces of the washer and bolt.The anti-rust coating film on the washer surface and the anti-rust coating film on the bolt bearing surface were brought into contact, and then heat treated in this state at 300°C for 15 minutes. After heat treatment, 100 M6 bolts with identical washers were dropped from a height of 50 cm onto a wire mesh (W: 430 mm x D: 430 mm x H: 20 mm, mesh opening 2.5 mm x 2.5 mm, wire diameter: 0.75 mm). The number of samples whose washers and bolts were still stuck together after the drop was counted. The adhesion rate was calculated using the following formula, and a rate of 30% or less was considered acceptable. Adhesion rate (%) = number of samples that remained attached after dropping / total number of samples (100) x 100

[0091] Example 2 In Example 1 (hydrolysis and polycondensation), 170 parts by mass of ion-exchanged water was changed to 94 parts by mass, 10.1 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 4.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]triethoxysilane (molecular weight 278.42) were used instead of 14.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 0.7 parts by mass of tetraethyl silicate, and 0.6 parts by mass of tetraethyl silicate was used instead of 0.7 parts by mass of tetraethyl silicate. A binder solution was produced in the same manner as in Example 1, and a pigment solution and an anti-rust paint composition were produced in the same manner as in Example 1. The anti-rust performance of the coating film obtained with the anti-rust paint composition was evaluated.

[0092] As a result of GPC measurement, the weight average molecular weight of the binder was 1.0 × 10 3 In addition, in (hydrolysis and polycondensation), the content ratio (mass ratio) of water (ion-exchanged water) to the first organosilicon compound (A) and the second organosilicon compound (B) was 6.3. The content of the surfactant in the anticorrosive coating composition obtained in Example 2 was 1.2 mass%.

[0093] An evaluation of the anti-rust performance of the coating showed that the steel plate coated with the prepared anti-rust paint composition showed almost no rust even after 500 hours, with only a small amount of red rust being observed in the X-shaped cuts made after coating. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was confirmed in the X-shaped cuts made after coating.

[0094] The coating film was subjected to an adhesion test in the same manner as in Example 1, and the adhesion rate was 19%, which was acceptable.

[0095] Example 3 In Example 1 (hydrolysis and polycondensation), except that 12.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 2.7 parts by mass of tetraethyl silicate were used instead of 14.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 0.7 parts by mass of tetraethyl silicate, a binder solution was produced in the same manner as in Example 1, a pigment solution was prepared, and an anti-rust coating composition was produced in the same manner as in Example 1, and the anti-rust performance of the coating film obtained from the anti-rust coating composition was evaluated.

[0096] As a result of GPC measurement, the weight average molecular weight of the binder was 0.7 × 10 3 In addition, in (hydrolysis and polycondensation), the content ratio (mass ratio) of water (ion-exchanged water) to the first organosilicon compound (A) and the second organosilicon compound (B) was 11.3. The content of the surfactant in the anticorrosive coating composition obtained in Example 3 was 1.2 mass%.

[0097] An evaluation of the anti-rust performance of the coating showed that the steel plate coated with the prepared anti-rust paint composition showed almost no rust even after 500 hours, with only a small amount of red rust being observed in the X-shaped cuts made after coating. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was confirmed in the X-shaped cuts made after coating.

[0098] The coating film was subjected to an adhesion test in the same manner as in Example 1, and the adhesion rate was found to be 29%, which was acceptable.

[0099] Example 4 In the hydrolysis and polycondensation steps of Example 1, instead of 170 parts by mass of ion-exchanged water, 110 parts by mass of ion-exchanged water and 10 parts by mass of a mixed aqueous solvent of 1-(2-hydroxypropoxy)-2-propanol / 2-(2-hydroxypropoxy)-1-propanol / 2-(2-hydroxy-1-methylethoxy)-1-propanol = 55 / 39 / 6 (%) were used, 13.8 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane was used instead of 14.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane, and 0.5 parts by mass of tetramethyl silicate (molecular weight 152.22) and 0.7 parts by mass of tetraethyl silicate were used instead of 0.7 parts by mass of tetraethyl silicate. Except for this, a binder solution was produced in the same manner as in Example 1, and a pigment solution and an anti-rust paint composition were prepared in the same manner as in Example 1. The anti-rust performance of the coating film obtained using the anti-rust paint composition was evaluated.

[0100] As a result of GPC measurement, the weight average molecular weight of the binder was 1.2 × 10 3 In addition, the content ratio (mass ratio) of water (ion-exchanged water) to the first organosilicon compound (A) and the second organosilicon compound (B) in (hydrolysis and polycondensation) was 7.3. The content of the surfactant in the anticorrosive coating composition obtained in Example 4 was 1.2 mass%.

[0101] An evaluation of the anti-rust performance of the coating showed that the steel plate coated with the prepared anti-rust paint composition showed almost no rust even after 500 hours, with only a small amount of red rust being observed in the X-shaped cuts made after coating. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was confirmed in the X-shaped cuts made after coating.

[0102] The coating film was subjected to an adhesion test in the same manner as in Example 1, and the adhesion rate was found to be 23%, which was acceptable.

[0103] Example 5 In Example 1 (hydrolysis and polycondensation), the binder solution was produced in the same manner as in Example 1, except that the heating in a 50°C incubator was changed from 10 days to 20 days, and the pigment solution and the anti-rust coating composition were prepared in the same manner as in Example 1, and the anti-rust performance of the coating film obtained by the anti-rust coating composition was evaluated.

[0104] GPC measurement revealed that the weight average molecular weight of the binder was 1.5 × 10 3 In addition, in (hydrolysis and polycondensation), the content ratio (mass ratio) of water (ion-exchanged water) to the first organosilicon compound (A) and the second organosilicon compound (B) was 11.3. The content of the surfactant in the anticorrosive coating composition obtained in Example 5 was 1.2 mass%.

[0105] An evaluation of the anti-rust performance of the coating showed that the steel plate coated with the prepared anti-rust paint composition showed almost no rust even after 500 hours, with only a small amount of red rust being observed in the X-shaped cuts made after coating. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was confirmed in the X-shaped cuts made after coating.

[0106] The coating film was subjected to an adhesion test in the same manner as in Example 1, and the adhesion rate was found to be 8%, which was acceptable.

[0107] (Comparative Example 1) In Example 1 (hydrolysis and polycondensation), a binder solution was produced in the same manner as in Example 1, except that 9.5 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 5.5 parts by mass of tetraethyl silicate were used instead of 14.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 0.7 parts by mass of tetraethyl silicate. A pigment solution was prepared and an anti-rust coating composition was produced in the same manner as in Example 1, and the anti-rust performance of the coating film obtained from the anti-rust coating composition was evaluated.

[0108] As a result of GPC measurement, the weight average molecular weight of the binder was 0.7 × 103 It was.

[0109] The rust-preventive performance of the coating was evaluated, and after 500 hours, the steel plate coated with the prepared anti-rust paint composition showed slight red rust formation in the X-shaped cuts made after coating, as well as in other areas. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was confirmed in the X-shaped cuts made after coating.

[0110] The coating film was subjected to an adhesion test in the same manner as in Example 1, and the adhesion rate was 46%, which was unacceptable.

[0111] (Comparative Example 2) In Example 1 (hydrolysis and polycondensation), 250 parts by mass of ion-exchanged water was used instead of 170 parts by mass of ion-exchanged water, and 15 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane was used instead of 14.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 0.7 parts by mass of tetraethyl silicate. A binder solution was produced in the same manner as in Example 1, and a pigment solution was prepared and a coating composition was produced in the same manner as in the examples. The rust-preventing performance of the coating film obtained from the coating composition was evaluated.

[0112] GPC measurement revealed that the weight average molecular weight of the binder was 0.5 × 10 3 It was.

[0113] An evaluation of the anti-rust performance of the coating showed that the steel plate coated with the prepared coating composition showed almost no rust even after 500 hours, with only a small amount of red rust being observed in the X-shaped cuts made after the coating was formed. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was confirmed in the X-shaped cuts made after the coating was formed.

[0114] The coating film was subjected to an adhesion test in the same manner as in Example 1, and the adhesion rate was 34%, which was unacceptable.

[0115] (Comparative Example 3) In Example 1 (hydrolysis and polycondensation), 170 parts by mass of ion-exchanged water was replaced with 80 parts by mass of ion-exchanged water, and 14.3 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 0.7 parts by mass of tetraethyl silicate were replaced with 11.6 parts by mass of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and 3.4 parts by mass of tetraethyl silicate. A binder solution was produced in the same manner as in Example 1, and a pigment solution was prepared and an anti-rust paint composition was produced in the same manner as in the Examples. The anti-rust performance of the coating film obtained with the anti-rust paint composition was evaluated.

[0116] GPC measurement revealed that the weight average molecular weight of the binder was 1.7 × 10 3 It was.

[0117] The rust-preventive performance of the coating was evaluated, and after 500 hours, the steel plate coated with the prepared anti-rust paint composition showed slight red rust formation in the X-shaped cuts made after coating, as well as in other areas. Furthermore, the accumulation of white rust derived from zinc due to the sacrificial corrosion protection of zinc was confirmed in the X-shaped cuts made after coating.

[0118] The coating film was subjected to an adhesion test in the same manner as in Example 1, and the adhesion rate was found to be 13%, which was acceptable.

[0119] Table 1 shows the conditions and results of each example and comparative example. Unless otherwise specified, "(A)" represents the mass of the first organosilicon compound (A) used in preparing the binder solution, and "(B)" represents the mass of the second organosilicon compound (B) used in preparing the binder solution. Here, "(B) / ((A)+(B)) (molar fraction)" represents the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B). Furthermore, "water" represents the mass of ion-exchanged water used in preparing the binder solution. "Water / (A)+(B)" represents the mass ratio of the water content relative to the total content of the first organosilicon compound (A) and the second organosilicon compound (B).

[0120] [Table 1]

[0121] From the above, it was at least confirmed that the anti-rust coating film formed by the anti-rust coating composition using the binder of this example has excellent corrosion resistance and adhesion.

Claims

1. an aqueous binder for an anticorrosive coating material obtained by hydrolyzing and polycondensing at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent; the first organosilicon compound (A) is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane; the second organosilicon compound (B) is at least one selected from the group consisting of tetramethyl silicate and tetraethyl silicate, the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the number of moles of the second organosilicon compound (B) is greater than 0 and not greater than 0.2; The weight average molecular weight (PEG equivalent) of the aqueous binder for the anticorrosive paint is 0.6 × 10 ３ 1.5 x 10 ３ The following is a water-based binder for anti-rust paint.

2. An anticorrosive paint composition comprising the aqueous binder for anticorrosive paint according to claim 1.

3. A method for producing an aqueous binder for an anticorrosive paint, comprising a reaction step of hydrolyzing and polycondensing at least a first organosilicon compound (A) and a second organosilicon compound (B) in an aqueous solvent to obtain the aqueous binder for an anticorrosive paint, the first organosilicon compound (A) is at least one selected from the group consisting of [3-(2,3-epoxypropoxy)propyl]trimethoxysilane and [3-(2,3-epoxypropoxy)propyl]triethoxysilane; the second organosilicon compound (B) is at least one selected from the group consisting of tetramethyl silicate and tetraethyl silicate, the reaction step is a step of hydrolyzing and polycondensing the first organosilicon compound (A) and the second organosilicon compound (B) in an aqueous solvent, in which the molar fraction of the number of moles of the second organosilicon compound (B) relative to the total number of moles of the first organosilicon compound (A) and the second organosilicon compound (B) is greater than 0 and not greater than 0.2; The weight average molecular weight (PEG equivalent) of the aqueous binder for the anticorrosive paint is 0.6 × 10 ３ 1.5 x 10 ３ Below is the A manufacturing method for water-based binders for anti-rust paints.

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