Water-repellent particle and method for producing water-repellent particle

Abstract

To provide water-repellent particles in which the performance balance between heat resistance and water repellency is enhanced.SOLUTION: A water-repellent particle comprises a particulate phenolic resin cured product and a silicone compound on the surface of the particulate phenolic resin cured product.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to water-repellent particles and a method for producing the water-repellent particles.

Background Art

[0002] As a water-repellent material, for example, a fluororesin is known. As a technique related to fluororesins, for example, the technique described in Patent Document 1 can be mentioned.

[0003] Patent Document 1 aims to provide a powder coating composition that is excellent in water and oil repellency, can maintain excellent water and oil repellency even when the surface is rubbed or provided in an environment where it comes into contact with water, and can form a coating film having excellent anti-biofouling properties with low adhesion of organisms such as mold and algae. A powder coating composition containing a polymer (A) composed of at least one selected from the following polymer (A1) and polyvinylidene fluoride and the following polymer (B) is described. Polymer (A1): A fluorine-containing non-block copolymer having a unit based on a fluoroolefin and a unit based on a monomer having a crosslinkable group. Polymer (B): A fluorine-containing block copolymer having a segment (α) with a fluorine atom content of 20% by mass or more and a segment (β) with a fluorine atom content of less than 20% by mass, wherein the difference in the numerical values of the fluorine atom content percentages represented by mass% of the segment (α) and the segment (β) is 10 or more, and at least one of the segment (α) and the segment (β) is a segment having a hydroxyl group.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides water-repellent particles with an improved balance of heat resistance and water-repellent performance.

Means for Solving the Problems

[0006] The inventors of the present invention have intensively studied to achieve the above problems. As a result, they have found that by including a silicone compound on the surface of the particulate phenol resin cured product, the balance of heat resistance and water-repellent performance of the obtained water-repellent particles can be improved, and thus the present invention has been completed.

[0007] According to the present invention, the following water-repellent particles and a method for producing the water-repellent particles are provided.

[0008] [1] A particulate phenol resin cured product, and a silicone compound on the surface of the particulate phenol resin cured product, and Water-repellent particles containing the same. [2] In the volume-based cumulative frequency distribution curve measured using a laser diffraction particle size distribution measuring device, the average particle diameter D 50 is 0.1 μm or more and 500 μm or less, and the water-repellent particles according to the above [1]. [3] The water-repellent particles according to the above [1] or [2], having a contact angle of 80° or more by the following (Method 1). (Method 1) Acetone is blended into a screw tube bottle so that the water-repellent particles are 20% by mass, and shaken to prepare a dispersion slurry. 0.5 mL of the dispersion slurry is dropped onto a slide glass with a dropper. The dispersion slurry is air-dried at room temperature for 4 hours together with the slide glass to obtain a sample with cured product particles adhering to the glass surface. 1.5 μL of water is dropped onto the sample, and the contact angle between the sample and the water droplet on the sample is evaluated using a contact angle meter (DM500 manufactured by Kyowa Interface Science Co., Ltd.). [4] The water-repellent particles according to any one of [1] to [3] above, having a melting point of 150 °C or higher according to JIS K 0064:1992. [5] The water-repellent particles according to any one of [1] to [4] above, wherein the particulate phenol resin cured product contains a cured product of a nitrogen-modified phenol resin. [6] The water-repellent particles according to [5] above, wherein the nitrogen-modified phenol resin contains a structural unit derived from an alkyleneamine represented by the following general formula (1). [Chemical formula] (In the above general formula (1), each R1 independently represents a linear or branched alkylene group having 1 to 10 carbon atoms) [7] The water-repellent particles according to any one of [1] to [6] above, wherein the content of the particulate phenol resin cured product is 50% by mass or more and less than 100% by mass when the total amount of the water-repellent particles is 100% by mass. [8] The water-repellent particles according to any one of [1] to [7] above, wherein the silicone compound contains an epoxy-modified silicone oil. [9] The water-repellent particles according to [8] above, wherein the epoxy-modified silicone oil contains one or more selected from the group consisting of a mono-terminal type epoxy-modified silicone oil, a bi-terminal type epoxy-modified silicone oil, a side-chain type epoxy-modified silicone oil, and an alicyclic epoxy-modified silicone oil.

[10] The water-repellent particles according to any one of [1] to [9] above, wherein the content of the silicone compound is 0.01 part by mass or more and 3.0 parts by mass or less when the particulate phenol resin cured product is 100 parts by mass.

[11] The water-repellent particles according to any one of [1] to

[10] above, wherein the fluorine content is 1.0% by mass or less when the total amount of the water-repellent particles is 100% by mass.

[12] A method for producing the water-repellent particles according to any one of [1] to

[11] above, Step (A) of preparing a particulate phenolic resin cured product, and step (B) of mixing a silicone compound and the particulate phenolic resin cured product, which is a method for producing water-repellent particles.

[13] The production method of the water-repellent particles according to

[12] above, wherein the mixing amount of the silicone compound is 0.01 part by mass or more and 5.0 parts by mass or less when the particulate phenolic resin cured product is 100 parts by mass.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide water-repellent particles with an improved balance of heat resistance and water repellency.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described based on embodiments. In this embodiment, "A to B" indicating a numerical range represents A or more and B or less unless otherwise specified.

[0011] <Water-repellent particles> The water-repellent particles of this embodiment include a particulate phenolic resin cured product and a silicone compound on the surface of the particulate phenolic resin cured product.

[0012] According to the water-repellent particles of this embodiment, it is possible to provide water-repellent particles with an improved balance of heat resistance and water repellency. This is considered to be because a silicone compound having excellent water repellency is present on the surface of the particulate phenolic resin cured product having excellent heat resistance, and the water repellency by the silicone compound can be efficiently imparted without impairing the heat resistance of the phenolic resin.

[0013] Hereinafter, each component contained in the water-repellent particles of this embodiment will be described in more detail.

[0014] [Particulate phenolic resin cured product] The water-repellent particles of this embodiment include a particulate phenolic resin cured product from the viewpoint of improving heat resistance. From the viewpoint of further improving heat resistance, the particulate phenol resin cured product of the present embodiment preferably contains a cured product of a resol resin. The resol resin of the present embodiment includes a resin obtained by condensing or copolymerizing phenols and aldehydes under a basic catalyst, and preferably contains one or more selected from the group consisting of a phenol resol resin, a cresol resol resin, a phenol cresol resol resin, and a phenol bisphenol A resol resin.

[0015] The phenols of the present embodiment preferably contain one or more selected from the group consisting of phenol, o-dihydroxybenzene (i.e., catechol), m-dihydroxybenzene (i.e., resorcinol, or resorcin), p-dihydroxybenzene (i.e., hydroquinone), 1,2,3-trihydroxybenzene (i.e., pyrogallol), o-cresol, m-cresol, p-cresol, oxocresol, ethylphenol, butylphenol, octylphenol, nonylphenol, xylenol, 3-pentadecylphenol, 3-pentadecylphenol monoene, 3-pentadecylphenol diene, 3-pentadecylphenol triene, 1,3-dihydroxy-5-pentadecylbenzene, 1,3-dihydroxy-5-pentadecylbenzene monoene, 1,3-dihydroxy-5-pentadecylbenzene diene, 1,3-dihydroxy-5-pentadecylbenzene triene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene monoene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene diene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene triene, urushiol, bisphenol A, bisphenol F, bisphenol S, p-phenylphenol, and styrenated phenol. From the viewpoint of further improving the performance balance of heat resistance and the mechanical properties of the resulting particulate phenol resin cured product, more preferably, it contains one or more selected from the group consisting of phenol and cresol, and even more preferably, it contains phenol.

[0016] The aldehydes of the present embodiment preferably include one or more selected from the group consisting of formaldehyde, paraformaldehyde, polyoxymethylene, trioxane, acetaldehyde, paraldehyde, butyraldehyde, crotonaldehyde, benzaldehyde, hydroxybenzaldehyde, terephthalaldehyde, salicylaldehyde, furfural, and glyoxal. From the viewpoint of further improving the balance of heat resistance and the mechanical properties of the resulting particulate phenol resin cured product, more preferably, they include one or more selected from the group consisting of formaldehyde, paraformaldehyde, and acetaldehyde, and even more preferably include formaldehyde. Note that, as the aldehydes of the present embodiment, compounds that are sources of aldehyde compounds such as hexamethylenetetramine and methoxymethylmelamines may be used.

[0017] The basic catalyst of the present embodiment preferably includes one or more selected from the group consisting of hydroxides of alkali metals such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; oxides and hydroxides of alkaline earth metals such as calcium, magnesium, and barium; aqueous ammonia, N-(2-aminoethyl)propanolamine, triethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-(2-aminoethyl)ethanolamine, and hexamethylenetetramine (i.e., hexamine), etc. amines. From the viewpoint of further improving the balance of heat resistance and the mechanical properties of the resulting particulate phenol resin cured product, more preferably, it includes one or more selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-(2-aminoethyl)ethanolamine, and hexamethylenetetramine, and even more preferably includes triethylenetetramine.

[0018] The cured particulate phenol resin of the present embodiment preferably contains a cured nitrogen-modified phenol resin from the viewpoint of enhancing reactivity with a silicone compound and improving water repellency. The nitrogen-modified phenol resin of the present embodiment preferably contains a structural unit derived from an alkyleneamine represented by the following general formula (1) from the viewpoint of improving the performance balance between heat resistance and water repellency.

[0019]

Chemical formula

[0020] In the above general formula (1), each R1 independently represents a linear or branched alkylene group having 1 to 10 carbon atoms. The number of carbon atoms of the alkylene group of R1 is preferably 1 to 10, more preferably 2 to 6, and still more preferably 2 to 4 from the viewpoint of further improving the performance balance among heat resistance, water repellency, and the mechanical properties of the resulting cured particulate phenol resin.

[0021] The nitrogen-modified phenol resin of the present embodiment contains a structural unit derived from ethylenediamine represented by the following formula (2) from the viewpoint of improving the performance balance between heat resistance and water repellency.

[0022]

Chemical formula

[0023] In the present embodiment, the nitrogen-modified phenol resin of the present embodiment is preferably crosslinked with a structural unit derived from ethylenediamine represented by the formula (2), that is, it is preferably an ethylene crosslinked product.

[0024] From the perspective of improving the performance balance of heat resistance and water repellency, the content ratio of the structural unit derived from ethyleneamine in the nitrogen-modified phenol resin of this embodiment is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less. The content ratio of the structural unit derived from ethyleneamine can be calculated based on the following formula. The nitrogen content (mass%) in the formula can be measured by an elemental analysis method. Content ratio of the structural unit derived from ethyleneamine = nitrogen content × (43 / 14)

[0025] From the perspective of improving the performance balance of heat resistance and water repellency, when the total amount of the water-repellent particles of this embodiment is 100% by mass, the content of the particulate phenol resin cured product of this embodiment in the water-repellent particles of this embodiment is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, and preferably less than 100% by mass, more preferably 99% by mass or less. That is, from the perspective of improving the performance balance of heat resistance and water repellency, when the total amount of the water-repellent particles of this embodiment is 100% by mass, the content of the particulate phenol resin cured product of this embodiment in the water-repellent particles of this embodiment is preferably 50% by mass or more and less than 100% by mass, more preferably 60% by mass or more and less than 100% by mass, still more preferably 70% by mass or more and less than 100% by mass, still more preferably 80% by mass or more and 99% by mass or less, still more preferably 90% by mass or more and 99% by mass or less.

[0026] [Silicone compound] From the perspective of improving water repellency, the water-repellent particles of this embodiment contain a silicone compound on the surface of the particulate phenol resin cured product. From the perspective of chemically bonding with the phenol resin cured product and further improving water repellency, the silicone compound of this embodiment contains an epoxy-modified silicone oil.

[0027] From the perspective of further improving water repellency, the epoxy-modified silicone oil of this embodiment preferably contains one or more selected from the group consisting of mono-terminal epoxy-modified silicone oil, bi-terminal epoxy-modified silicone oil, side-chain epoxy-modified silicone oil, and alicyclic epoxy-modified silicone oil, and more preferably contains bi-terminal epoxy-modified silicone oil.

[0028] Examples of the mono-terminal epoxy-modified silicone oil of this embodiment include X-22-173BX and X-22-173DX manufactured by Shin-Etsu Silicone Co., Ltd. Examples of the bi-terminal epoxy-modified silicone oil of this embodiment include X-22-163, KF-105, X-22-163A, X-22-163B, and X-22-163C manufactured by Shin-Etsu Silicone Co., Ltd. Examples of the side-chain epoxy-modified silicone oil of this embodiment include X-22-343, KF-101, KF-1001, X-22-2000, X-22-4741, KF-1002, and KF-1005 manufactured by Shin-Etsu Silicone Co., Ltd. Examples of the alicyclic epoxy-modified silicone oil of this embodiment include X-22-2046, KF-102, X-22-169AS, and X-22-169B manufactured by Shin-Etsu Silicone Co., Ltd.

[0029] From the perspective of improving the performance balance between heat resistance and water repellency, when the content of the silicone compound of this embodiment in the water-repellent particles is based on 100 parts by mass of the particulate phenol resin cured product, it is preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, still more preferably 0.05 part by mass or more, still more preferably 0.07 part by mass or more, still more preferably 0.10 part by mass or more, and is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, still more preferably 2.0 parts by mass or less, still more preferably 1.5 parts by mass or less, still more preferably 1.0 part by mass or less. That is, from the viewpoint of improving the performance balance between heat resistance and water repellency, when the particulate phenol resin cured product is 100 parts by mass, the content of the silicone compound in the water-repellent particles of the present embodiment is preferably 0.01 part by mass or more and 3.0 parts by mass or less, more preferably 0.03 part by mass or more and 2.5 parts by mass or less, still more preferably 0.05 part by mass or more and 2.0 parts by mass or less, still more preferably 0.07 part by mass or more and 1.5 parts by mass or less, and still more preferably 0.10 part by mass or more and 1.0 part by mass or less.

[0030] [Physical properties] In the cumulative frequency distribution curve based on volume measured using a laser diffraction particle size distribution measuring apparatus for the water-repellent particles of the present embodiment, the average particle diameter D at the time when the cumulative frequency is 50% 50 is, from the viewpoint of improving the performance balance between heat resistance and water repellency, preferably 0.1 μm or more, more preferably 0.5 μm or more, still more preferably 1.0 μm or more, still more preferably 3.0 μm or more, and still more preferably 5.0 μm or more, and is preferably 500 μm or less, more preferably 400 μm or less, still more preferably 300 μm or less, still more preferably 200 μm or less, and still more preferably 150 μm or less. That is, in the cumulative frequency distribution curve based on volume measured using a laser diffraction particle size distribution measuring apparatus for the water-repellent particles of the present embodiment, the average particle diameter D at the time when the cumulative frequency is 50% 50 is, from the viewpoint of improving the performance balance between heat resistance and water repellency, preferably 0.1 μm or more and 500 μm or less, more preferably 0.5 μm or more and 400 μm or less, still more preferably 1.0 μm or more and 300 μm or less, still more preferably 3.0 μm or more and 200 μm or less, and still more preferably 5.0 μm or more and 150 μm or less.

[0031] From the perspective of improving the balance of heat resistance and water repellency performance, the contact angle of the water-repellent particles of the present embodiment by the following (Method 1) is preferably 80° or more, more preferably 90° or more, still more preferably 100° or more, and even more preferably 110° or more. The upper limit is not particularly limited. For example, it may be 180° or less, 170° or less, 160° or less, 150° or less, 140° or less, or 130° or less. That is, from the perspective of improving the balance of heat resistance and water repellency performance, the contact angle of the water-repellent particles of the present embodiment by the following (Method 1) is preferably 80° or more and 180° or less, more preferably 90° or more and 180° or less, still more preferably 100° or more and 180° or less, even more preferably 110° or more and 180° or less, still more preferably 110° or more and 170° or less, still more preferably 110° or more and 160° or less, still more preferably 110° or more and 150° or less, still more preferably 110° or more and 140° or less, and still more preferably 110° or more and 130° or less.

[0032] (Method 1) Acetone is blended into a screw tube bottle so that the above water-repellent particles account for 20% by mass, and the mixture is shaken to prepare a dispersion slurry. 0.5 mL of the above dispersion slurry is dropped onto a slide glass with a dropper. The above dispersion slurry is air-dried at room temperature for 4 hours together with the above slide glass to obtain a sample with cured product particles adhering to the glass surface. 1.5 μL of water is dropped onto the above sample, and the contact angle between the above sample and the water droplet on the above sample is evaluated using a contact angle meter (DM500 manufactured by Kyowa Interface Science Co., Ltd.).

[0033] From the perspective of improving heat resistance, the melting point of the water-repellent particles of the present embodiment according to JIS K 0064:1992 is preferably 150°C or higher, more preferably 180°C or higher, and still more preferably 200°C or higher. The upper limit is not particularly limited. For example, it may be 500°C or lower, 450°C or lower, or 400°C or lower.

[0034] From the perspective of improving the performance balance between heat resistance and environmental performance, when the total amount of the water-repellent particles in this embodiment is 100% by mass, the fluorine content is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, still more preferably 0.3% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.01% by mass or less, and still more preferably below the detection limit value.

[0035] <Method for producing water-repellent particles> The method for producing the water-repellent particles of this embodiment preferably includes a step (A) of preparing a particulate phenol resin cured product and a step (B) of mixing a silicone compound and the particulate phenol resin cured product. Hereinafter, the details of each step will be described.

[0036] [Step (A) of preparing a particulate phenol resin cured product] First, a particulate phenol resin cured product is prepared. The particulate phenol resin cured product may be obtained, for example, by curing a resin obtained by reacting phenols and aldehydes with an acidic or basic catalyst and then pulverizing it. Preferably, it can be prepared by a method including a step (A1) of preparing a mixed solution containing phenols, aldehydes, a hydrophilic polymer, and a hydrophilic solvent, a step (A2) of stirring the mixed solution to react the phenols and aldehydes to form suspended particles, and a step (A3) of curing the suspended particles. Hereinafter, the details of each step will be described.

[0037] [Step (A1) of preparing a mixed solution containing phenols, aldehydes, a hydrophilic polymer, and a hydrophilic solvent] In step (A1) of preparing a mixed solution containing phenols, aldehydes, a hydrophilic polymer, and a hydrophilic solvent, a mixed solution containing phenols, aldehydes, a hydrophilic polymer, and a hydrophilic solvent is prepared.

[0038] The phenols of the present embodiment preferably include one or more selected from the group consisting of phenol, o-dihydroxybenzene (i.e., catechol), m-dihydroxybenzene (i.e., resorcinol, or resorcine), p-dihydroxybenzene (i.e., hydroquinone), 1,2,3-trihydroxybenzene (i.e., pyrogallol), o-cresol, m-cresol, p-cresol, oxocresol, ethylphenol, butylphenol, octylphenol, nonylphenol, xylenol, 3-pentadecylphenol, 3-pentadecylphenol monoene, 3-pentadecylphenol diene, 3-pentadecylphenol triene, 1,3-dihydroxy-5-pentadecylbenzene, 1,3-dihydroxy-5-pentadecylbenzene monoene, 1,3-dihydroxy-5-pentadecylbenzene diene, 1,3-dihydroxy-5-pentadecylbenzene triene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene monoene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene diene, 2-methyl-1,3-dihydroxy-5-pentadecylbenzene triene, urushiol, bisphenol A, bisphenol F, bisphenol S, p-phenylphenol, and styrenated phenol. From the viewpoint of being able to further improve the balance of heat resistance and the mechanical properties of the resulting particulate phenol resin cured product, more preferably, it includes one or more selected from the group consisting of phenol and cresol, and even more preferably, it includes phenol.

[0039] The aldehydes of this embodiment preferably include one or more selected from the group consisting of formaldehyde, paraformaldehyde, polyoxymethylene, trioxane, acetaldehyde, paraldehyde, butyraldehyde, crotonaldehyde, benzaldehyde, hydroxybenzaldehyde, terephthalaldehyde, salicylaldehyde, furfural, and glyoxal. From the perspective of further improving the heat resistance and the performance balance of the mechanical properties of the resulting particulate phenolic resin cured product, more preferably, it includes one or more selected from the group consisting of formaldehyde, paraformaldehyde, and acetaldehyde, and even more preferably includes formaldehyde. Note that as the aldehydes of this embodiment, a compound that serves as a source of an aldehyde compound such as hexamethylenetetramine may be used.

[0040] The molar ratio of aldehydes to phenols (aldehydes / phenols) in the mixed solution of this embodiment facilitates the control of the shape of the resulting particulate phenolic resin cured product, and from the perspective of further improving the heat resistance and the performance balance of the mechanical properties of the resulting particulate phenolic resin cured product, it is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, even more preferably 0.4 or more, and preferably 4.0 or less, more preferably 3.0 or less, even more preferably 2.0 or less, even more preferably 1.0 or less, even more preferably 0.9 or less, even more preferably 0.8 or less, even more preferably 0.7 or less, even more preferably 0.6 or less, even more preferably 0.5 or less.

[0041] The hydrophilic polymer of this embodiment adheres to the surfaces of phenols and aldehydes and can improve the dispersibility of phenols and aldehydes in a hydrophilic solvent.

[0042] The hydrophilic polymer of the present embodiment preferably contains one or more selected from the group consisting of hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose cationized product, polyvinyl alcohol, alginic acid, guar gum, and gum arabic, and facilitates the control of the shape of the resulting particulate phenolic resin cured product. From the viewpoint of further improving the heat resistance and the performance balance of the mechanical properties of the resulting particulate phenolic resin cured product, more preferably, it contains one or more selected from the group consisting of hydroxyethyl cellulose, guar gum, and gum arabic, and still more preferably contains hydroxyethyl cellulose.

[0043] The hydrophilic solvent of the present embodiment preferably contains one or more selected from the group consisting of water, methyl alcohol, ethyl alcohol, ethylene glycol, diethylene glycol, glycerin, polyethylene glycol, acetone, tetrahydrofuran, and N-methylpyrrolidone, and facilitates the control of the shape of the resulting particulate phenolic resin cured product. From the viewpoint of further improving the heat resistance and the performance balance of the mechanical properties of the resulting particulate phenolic resin cured product, more preferably, it contains one or more selected from the group consisting of water, methyl alcohol, ethyl alcohol, ethylene glycol, and diethylene glycol, and still more preferably contains one or more selected from the group consisting of water and ethylene glycol.

[0044] (Step (A2) of stirring the mixed solution, reacting phenols and aldehydes, and forming suspended particles) In step (A2) of stirring the mixed solution, reacting phenols and aldehydes, and forming suspended particles, the mixed solution is stirred, phenols and aldehydes are reacted, and suspended particles are formed. As a method of reacting phenols and aldehydes to form suspended particles, it can be carried out by stirring the mixed solution.

[0045] The reaction between phenols and aldehydes is carried out, for example, under a basic catalyst. In step (A2), the phenols and aldehydes react to form a resol-type phenol resin, and further, a part of the resol-type phenol resin crosslinks with each other to form a crosslinked product. In step (A2), the crosslinking does not proceed completely, and the crosslinking further proceeds and cures in step (A3) described later. That is, the suspended particles contain, for example, a resol-type phenol resin and a crosslinked product of the resol-type phenol resin.

[0046] In addition, after forming the suspended particles, for example, the suspended particles may be washed to remove the hydrophilic polymer on the surface of the suspended particles. The handleability due to aggregation and adhesion of the particles of the particulate phenol resin cured product can be further improved.

[0047] The method of washing is not limited, but for example, a method of dispersing the suspended particles in a hydrophilic solvent such as a large amount of pure water can be used. Thereby, the hydrophilic solvent on the surface of the suspended particles can be removed. As a method of washing, for example, it is preferable to wash 3 times or more, more preferably 5 times or more, with a hydrophilic solvent that is 1 time or more and 2 times or less the mass of the suspended particles. Thereby, the content of impurities can be reduced to a desired numerical range, which is preferable in that it can also be applied to applications that require a high degree of cleanliness. In addition, although it is preferable to increase the number of washing times as much as possible without complicating the production process, the upper limit value of the number of washing times may be, for example, 10 times or less.

[0048] The basic catalyst of the present embodiment is not particularly limited as long as it is used in the reaction of phenols and aldehydes for producing a resol type phenol resin, and can be used. From the viewpoint of improving the heat resistance and the performance balance of the mechanical properties of the obtained particulate phenol resin cured product, the basic catalyst of the present embodiment is preferably a hydroxide of an alkali metal such as sodium hydroxide, lithium hydroxide, potassium hydroxide; oxides and hydroxides of alkaline earth metals such as calcium, magnesium, barium; ammonia water, N-(2-aminoethyl)propanolamine, triethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-(2-aminoethyl)ethanolamine and hexamethylenetetramine (i.e., hexamine), and the like, and more preferably contains one or more selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N-(2-aminoethyl)ethanolamine, hexamethylenetetramine, and even more preferably contains triethylenetetramine.

[0049] (Step (A3) of curing the suspended particles) In the step (A3) of curing the suspended particles, the suspended particles (particulate phenol resin) are heat-treated to cure the suspended particles and obtain a particulate phenol resin cured product.

[0050] Specifically, by heat treatment, the phenol resin in the suspended particles is further crosslinked to form a crosslinked body and cured, while removing the hydrophilic solvent from the suspended particles. Thereby, in the step (B) of mixing the silicone compound described later with the particulate phenol resin cured product, the silicone compound on the surface of the particulate phenol resin cured product can react more efficiently. The method for heat-treating the suspended particles is not limited, and it can be carried out by a conventionally known method under atmospheric pressure, reduced pressure, in a gas, etc. From the viewpoint of efficiently removing the hydrophilic solvent from the suspended particles, the method for heat-treating the suspended particles is preferably a method of heat-treating with a device including one or more selected from the group consisting of a hot air dryer and a reduced-pressure stirring dryer.

[0051] From the viewpoint of further improving the balance of heat resistance and the mechanical properties of the resulting particulate phenol resin cured product, the temperature of the heat treatment in step (A3) is preferably less than 200 °C, more preferably less than 170 °C, still more preferably 150 °C or less, still more preferably 135 °C or less, still more preferably 130 °C or less, and preferably more than 50 °C, more preferably 60 °C or more, still more preferably 70 °C or more, still more preferably 80 °C or more, still more preferably 90 °C or more, still more preferably 100 °C or more.

[0052] From the viewpoint of working efficiency, the time of the heat treatment in step (A3) is preferably 48 hours or less, more preferably 42 hours or less, still more preferably 36 hours or less, still more preferably 30 hours or less, still more preferably 25 hours or less, and from the viewpoint of further improving the balance of heat resistance and the mechanical properties of the resulting particulate phenol resin cured product, it is preferably 0.1 hour or more, more preferably 0.5 hour or more, still more preferably 1 hour or more, still more preferably 2 hours or more, still more preferably 3 hours or more, still more preferably 6 hours or more, still more preferably 12 hours or more, still more preferably 18 hours or more.

[0053] In step (A) of preparing the particulate phenol resin cured product, a drying step may be provided as necessary. By heat-treating the suspended particles (particulate phenol resin) at a temperature of 60 °C or more and 150 °C or less, the hydrophilic solvent that could not be completely removed in the above step (A3) can be removed from the suspended particles. The method for heat treatment is not limited, and any conventionally known method can be used as long as it is carried out in a gas under atmospheric pressure or under reduced pressure.

[0054] As described above, the process (A3) and the drying process can adopt a conventionally known method as long as they are continuously carried out under atmospheric pressure in a gas or under reduced pressure. From the viewpoint of continuously carrying out the process (A3) and the drying process, as a method for carrying out the process (A3) and the drying process, for example, it is preferable to use a hot air dryer or a vacuum stirring dryer.

[0055] Also, if necessary, the particulate phenol resin cured product after drying may be further crushed. Examples of the crushing method include impact crushers such as pin mills, knife mills, and hammer mills, and airflow crushers such as jet mills and counter jet mills.

[0056] [Step (B) of mixing a silicone compound and a particulate phenol resin cured product] Next, a silicone compound is mixed with the particulate phenol resin cured product prepared in the above step (A).

[0057] In the method for producing the water-repellent particles of the present embodiment, from the viewpoint of further improving the performance balance of heat resistance and water repellency, when the particulate phenol resin cured product is 100 parts by mass, the mixing amount of the silicone compound is preferably 0.01 part by mass or more and 5.0 parts by mass or less, more preferably 0.03 part by mass or more and 4.0 parts by mass or less, still more preferably 0.05 part by mass or more and 3.0 parts by mass or less, still more preferably 0.07 part by mass or more and 2.0 parts by mass or less, and still more preferably 0.10 part by mass or more and 1.0 part by mass or less.

[0058] In step (B), from the viewpoint of more uniformly dispersing the silicone compound and the particulate phenol resin cured product, it is preferable to further mix a solvent. From the perspective of more uniformly dispersing the silicone compound and the particulate phenol resin cured product, the solvent of the present embodiment preferably contains one or more selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether acetate, pentane, hexane, heptane, octane, kerosene, dimethylacetamide, N-methylpyrrolidone, and tetrahydrofuran, and more preferably contains methyl ethyl ketone.

[0059] The method for producing the water-repellent particles of the present embodiment preferably includes a step (C) of heat-treating the particulate phenol resin cured product containing a silicone compound on its surface after the step (B). By heat-treating the particulate phenol resin cured product containing a silicone compound on its surface at a temperature of 60°C or higher and 150°C or lower, the silicone compound on the surface of the particulate phenol resin cured product can be reacted more efficiently. The method of heat treatment is not limited, and it can be carried out by a conventionally known method such as under atmospheric pressure, under reduced pressure, in a gas, in a liquid, etc. Also, heating may be continued as it is in the step (B) to react the silicone compound on the surface of the particulate phenol resin cured product.

[0060] From the perspective of further improving the performance balance of heat resistance and water repellency, the heat treatment temperature in the step (C) is preferably less than 200°C, more preferably less than 170°C, still more preferably 150°C or lower, still more preferably 140°C or lower, still more preferably 130°C or lower, still more preferably 120°C or lower, and is preferably more than 50°C, more preferably 60°C or higher, still more preferably 70°C or higher, still more preferably 80°C or higher, still more preferably 90°C or higher, still more preferably 100°C or higher.

[0061] The heat treatment time in step (C) is preferably 24 hours or less, more preferably 18 hours or less, still more preferably 12 hours or less, and even more preferably 6 hours or less from the viewpoint of working efficiency, and is preferably 0.1 hours or more, more preferably 0.5 hours or more, still more preferably 1 hour or more, even more preferably 2 hours or more, and even more preferably 3 hours or more from the viewpoint of further improving the performance balance of heat resistance and water repellency.

[0062] The method for producing the water-repellent particles of the present embodiment preferably includes a step (D) of washing the water-repellent particles after step (C). By washing the water-repellent particles, unreacted silicone compounds can be removed from the water-repellent particles, and aggregation and adhesion of the water-repellent particles to each other can be suppressed.

[0063] The method for washing the water-repellent particles is not limited, but for example, a method of dispersing the water-repellent particles in a washing solvent such as an organic solvent can be used. As the washing method, for example, it is preferable to perform washing 3 times or more, and more preferably 5 times or more, with a washing solvent that is 1 to 2 times the mass of the water-repellent particles. It should be noted that the number of washing times is preferably increased within a range where the production process does not become complicated, but the upper limit of the number of washing times may be, for example, 10 times or less.

[0064] The washing solvent used in the step (D) of washing the water-repellent particles preferably contains one or more selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether acetate, pentane, hexane, heptane, octane, kerosene, dimethylacetamide, N-methylpyrrolidone, and tetrahydrofuran, and more preferably contains methyl ethyl ketone.

[0065] The method for producing the water-repellent particles of the present embodiment preferably includes a step (E) of drying the water-repellent particles after step (D). By heat-treating the water-repellent particles at a temperature of 60°C or higher and 150°C or lower, unreacted silicone compounds and cleaning solvents can be removed from the water-repellent particles. The method of heat treatment is not limited, and any conventionally known method can be used as long as it is carried out in a gas under atmospheric pressure or under reduced pressure.

[0066] Further, if necessary, the dried water-repellent particles may be further crushed. Examples of the method for crushing the water-repellent particles include impact crushers such as pin mills, knife mills, and hammer mills, and airflow crushers such as jet mills and counter jet mills.

[0067] <Uses of the water-repellent particles> The water-repellent particles of the present embodiment can be suitably used for toners, powder coatings, functional coating materials, and filters.

[0068] The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention.

Examples

[0069] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereby.

[0070] [Examples · Comparative Examples] (Preparation of particulate phenol resin cured product A) 1000 parts by mass of phenol, which is a phenol, 1120 parts by mass of 37% aqueous formaldehyde solution, which is an aldehyde, 200 parts by mass of 2% aqueous hydroxyethyl cellulose solution, which is a hydrophilic polymer, 41 parts by mass of ethylene glycol, which is a hydrophilic solvent, and 235 parts by mass of water were prepared as raw material components of the mixture. Next, the above raw material components were put into a reaction vessel equipped with a heating and stirring device and uniformly mixed to prepare a mixture. Then, the mixture was heated to 95°C, and 270 parts by mass of 33% aqueous triethylenetetramine solution was added to the mixture, and the reaction was carried out with stirring at 95°C for 6 hours to obtain suspended particles. The obtained suspended particles were taken out into a box-shaped container and dried at 110°C for 24 hours with a hot air circulation dryer while being cured to obtain a dried product. The obtained dried product was treated with a crusher (ZM100, manufactured by RETSCH) to obtain particulate phenol resin cured product A (hereinafter, also referred to as cured product A). When the shape of cured product A was observed using a scanning electron microscope (JCM-6000, manufactured by JEOL Ltd.) for the obtained cured product A, cured product A was spherical.

[0071] (Preparation of particulate phenol resin cured product B) 1000 parts by mass of phenol which is a phenolic compound, 1120 parts by mass of 37% aqueous formaldehyde solution which is an aldehyde compound, 200 parts by mass of 2% aqueous hydroxyethyl cellulose solution which is a hydrophilic polymer, 41 parts by mass of ethylene glycol which is a hydrophilic solvent, and 235 parts by mass of water were prepared as raw material components of the mixture. Next, the above raw material components were put into a reaction vessel equipped with a heating and stirring device and uniformly mixed to prepare a mixture. Then, the mixture was heated until it reached 60°C, 270 parts by mass of 33% aqueous triethylenetetramine solution was added to the mixture, and the reaction was carried out with stirring at 50°C for 3 hours, and further reacted at 95°C for 6 hours to obtain suspended particles. The obtained suspended particles were taken out into a box-shaped container and dried at 110°C for 24 hours with a hot air circulation dryer to obtain a dried product. The obtained dried product was treated with a crusher (ZM100 manufactured by RETSCH) to obtain particulate phenolic resin cured product B (hereinafter also referred to as cured product B). Regarding the obtained cured product B, when the shape of the cured product B was observed using a scanning electron microscope (JCM-6000 manufactured by JEOL Ltd.), the cured product B was spherical.

[0072] (Preparation of Particulate Phenolic Resin Cured Product C) 1000 parts by mass of phenol which is a phenolic compound was added with 10 parts of oxalic acid as a catalyst, 690 parts by mass of 37% aqueous formaldehyde solution which is an aldehyde compound was added, and the reaction was carried out at 100°C for 2 hours. Then, the temperature was raised while removing water until it reached 150°C, and the temperature was raised to 200°C under a vacuum condition of 20 torr to remove unreacted monomers. The obtained reaction product was taken out and cooled to room temperature to obtain an uncured solid resin. 10 parts of hexamethylenetetramine was added to 100 parts of this uncured solid resin, and the mixture was pulverized and mixed with a pulverizer. The obtained mixture was subjected to a curing treatment at 200°C for 2 hours, cooled to room temperature, and then pulverized with a pulverizer (ZM100 manufactured by RETSCH) to obtain particulate phenolic resin cured product C (hereinafter also referred to as cured product C).

[0073] (Preparation of Particulate Phenolic Resin Cured Product D) 1000 parts by mass of phenol, which is a phenolic compound, 25 parts of sodium hydroxide as a catalyst were added, 1113 parts by mass of a 37% aqueous formaldehyde solution, which is an aldehyde, was added, and the mixture was reacted at 80 °C for 2 hours. Then, the temperature was raised to 70 °C under a vacuum condition of 20 torr to remove water. The obtained reaction product was cooled to room temperature and taken out to obtain an uncured liquid resin. The obtained liquid resin was subjected to a curing treatment at 200 °C for 4 hours, cooled to room temperature, and then pulverized with a pulverizer (ZM100 manufactured by RETSCH) to obtain particulate phenol resin cured product D (hereinafter also referred to as cured product D).

[0074] (Example 1) A mixed solution of 1 part by mass of epoxy-modified silicone oil (KF-105 manufactured by Shin-Etsu Chemical Co., Ltd.) and 30 parts by mass of methyl ethyl ketone was added to 100 parts by mass of cured product A and mixed until the whole was uniformly wetted. This was taken out into a box-shaped container and heat-treated at 110 °C for 4 hours with a hot air circulation dryer to react the epoxy-modified silicone oil on the surface of the cured product particles. The obtained particles were dispersed in 100 parts of methyl ethyl ketone, and suction filtration and recovery were repeated 3 times to wash away the excess epoxy-modified silicone oil on the surface. This was taken out into a box-shaped container and dried at 110 °C for 1 hour with a hot air circulation dryer. The obtained dried product was treated with an agglomerate using a crusher (ZM100 manufactured by RETSCH) to obtain water-repellent particles 1 with a water-repellent treatment on the surface. When the whole of the water-repellent particles 1 was 100% by mass, the fluorine content of the water-repellent particles 1 was 0.0% by mass.

[0075] (Example 2) Water-repellent particles 2 with a water-repellent treatment on the surface were obtained in the same manner as in Example 1 except that the content of the epoxy-modified silicone oil in the mixed solution of Example 1 was changed to 0.1 part by mass. When the whole of the water-repellent particles 2 was 100% by mass, the fluorine content of the water-repellent particles 2 was 0.0% by mass.

[0076] (Example 3) Instead of the cured product A in Example 1 above, water-repellent particles 3 with a water-repellent treated surface were obtained by the same operation as in Example 1 above, except that the cured product B was used. When the total amount of the water-repellent particles 3 was 100% by mass, the fluorine content of the water-repellent particles 3 was 0.0% by mass.

[0077] (Example 4) Instead of the cured product A in Example 1 above, water-repellent particles 4 with a water-repellent treated surface were obtained by the same operation as in Example 1 above, except that the cured product C was used. When the total amount of the water-repellent particles 4 was 100% by mass, the fluorine content of the water-repellent particles 4 was 0.0% by mass.

[0078] (Example 5) Instead of the cured product A in Example 1 above, water-repellent particles 5 with a water-repellent treated surface were obtained by the same operation as in Example 1 above, except that the cured product D was used. When the total amount of the water-repellent particles 5 was 100% by mass, the fluorine content of the water-repellent particles 5 was 0.0% by mass.

[0079] (Comparative Example 1) Using the cured product A as it was, particles 1 containing no silicone compound were obtained. When the total amount of the particles 1 was 100% by mass, the fluorine content of the particles 1 was 0.0% by mass.

[0080] [Evaluation] (Average particle diameter D 50 ) Regarding the particles obtained in the examples and comparative examples, using a laser scattering particle size distribution analyzer (manufactured by Horiba, Ltd., LA-950), the average particle diameter D at which the cumulative value becomes 50% in the volume frequency particle size distribution measured by the laser diffraction scattering method 50 was measured. The results are shown in Table 1.

[0081] (Melting point) Regarding the particles obtained in the examples and comparative examples, the melting point according to JIS K 0064:1992 was measured. The results are shown in Table 1.

[0082] (Contact angle) The contact angles of the particles obtained in the examples and comparative examples with water droplets were evaluated. Acetone was blended into a screw tube bottle so that the particles obtained in the examples and comparative examples would be 20% by mass, and the mixture was shaken to prepare a dispersion slurry. 0.5 mL of the obtained dispersion slurry was dropped onto a slide glass with a dropper. The dropped dispersion slurry was air-dried at room temperature for 4 hours together with the slide glass to obtain a sample with cured product particles adhering to the glass surface. 1.5 μL of water was dropped onto this sample, and the contact angle between the sample and the water droplet on the sample was evaluated using a contact angle meter (DM500 manufactured by Kyowa Interface Science Co., Ltd.). The results are shown in Table 1. In Comparative Example 1, the water was immediately absorbed by the particles without being repelled, the contact angle was low, and the evaluation was impossible.

[0083]

Table 1

[0084] The water-repellent particles obtained in Examples 1 to 5, which contain a particulate phenol resin cured product and a silicone compound on the surface of the particulate phenol resin cured product, had an improved balance of heat resistance and water-repellent performance compared to Particle 1 that does not contain the silicone compound of Comparative Example 1.

Claims

1. A particulate phenol resin cured product, and a silicone compound on the surface of the particulate phenol resin cured product, The water-repellent particles containing these.

2. The average particle diameter D at the time when the cumulative frequency is 50% in the volume-based cumulative frequency distribution curve measured using a laser diffraction type particle size distribution measuring device ５０ is 0.1 μm or more and 500 μm or less, and the water-repellent particle according to claim 1.

3. The water-repellent particles according to claim 1 or 2, having a contact angle of 80° or more by the following (Method 1). (Method 1) Acetone is blended into a screw tube bottle so that the water-repellent particles are 20% by mass, and the mixture is shaken to prepare a dispersion slurry. 0.5 mL of the dispersion slurry is dropped onto a slide glass with a dropper. The dispersion slurry together with the slide glass is air-dried at room temperature for 4 hours to obtain a sample with cured product particles adhering to the glass surface. 1.5 μL of water is dropped onto the sample, and the contact angle between the sample and the water droplet on the sample is evaluated using a contact angle meter (DM500 manufactured by Kyowa Interface Science Co., Ltd.).

4. The water-repellent particles according to claim 1 or 2, having a melting point of 150° C. or more according to JIS K 0064:1992.

5. The water-repellent particles according to claim 1 or 2, wherein the particulate phenol resin cured product contains a cured product of a nitrogen-modified phenol resin.

6. The water-repellent particles according to claim 5, wherein the nitrogen-modified phenol resin contains a structural unit derived from an alkyleneamine represented by the following general formula (1). 【Chemical 1】 (In the general formula (1), R １ each independently represents a linear or branched alkylene group having 1 to 10 carbon atoms)

7. The water-repellent particles according to claim 1 or 2, wherein the content of the particulate phenol resin cured product is 50% by mass or more and less than 100% by mass when the total amount of the water-repellent particles is 100% by mass.

8. The water-repellent particles according to claim 1 or 2, wherein the silicone compound contains an epoxy-modified silicone oil.

9. The water-repellent particles according to claim 8, wherein the epoxy-modified silicone oil contains one or more selected from the group consisting of a mono-terminal type epoxy-modified silicone oil, a bi-terminal type epoxy-modified silicone oil, a side-chain type epoxy-modified silicone oil, and an alicyclic epoxy-modified silicone oil.

10. The water-repellent particles according to claim 1 or 2, wherein the content of the silicone compound is 0.01 part by mass or more and 3.0 parts by mass or less when the particulate phenol resin cured product is 100 parts by mass.

11. The water-repellent particles according to claim 1 or 2, wherein the fluorine content is 1.0% by mass or less when the total amount of the water-repellent particles is 100% by mass.

12. A method for producing the water-repellent particles according to claim 1 or 2, A step (A) of preparing a particulate phenol resin cured product, A method for producing water-repellent particles, comprising a step (B) of mixing a silicone compound and the particulate phenol resin cured product.

13. The method for producing water-repellent particles according to claim 12, wherein the mixing amount of the silicone compound is 0.01 part by mass or more and 5.0 parts by mass or less when the particulate phenol resin cured product is 100 parts by mass.

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