Method for producing aggregates and method for producing powders and granules

Abstract

To provide a method for producing an aggregate and a method for producing powder granules which improve the recovery rate of the aggregate obtained from a latex of polymer fine particles.SOLUTION: There are used a two-fluid nozzle in which an air flow rate is set at less than 60 L / min for spraying the coagulant solution and / or a one-fluid nozzle for spraying the coagulant solution by spraying and / or dropping a latex of polymer fine particles in the vertical direction and spraying the coagulant solution in the horizontal direction.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing an aggregate and a method for producing a powder or granular material. [Background technology]

[0002] Powders of polymer fine particles are used as resin modifiers such as impact resistance modifiers, etc. As a method for producing such powders, a method has been proposed in which a latex of polymer fine particles is coagulated to form aggregates, and the aggregates are then dried.

[0003] As such a method, Patent Document 1 describes a method in which a latex of polymer fine particles containing a thickener is sprayed or dropped into a gas phase containing a coagulant solution in the form of an aerosol. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2017-61645 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional techniques are not sufficient in terms of the recovery rate of aggregates from the latex of polymer fine particles, and there is room for further improvement.

[0006] One embodiment of the present invention has been made in consideration of the above-mentioned problems, and its object is to provide a novel method for producing an agglomerate and a novel method for producing a powder or granule, which improve the recovery rate of the agglomerate of polymer fine particles from a latex of the polymer fine particles. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, one embodiment of the present invention includes the following features.

[0008] [1] A method for producing an aggregate, comprising a contacting step of spraying and / or dropping latex of polymer fine particles in a vertical direction and spraying a coagulant solution in a horizontal direction to bring the droplets of the latex into contact with the droplets of the coagulant solution, wherein in the contacting step, a two-fluid nozzle with an air flow rate set to less than 60 L / min is used for spraying the coagulant solution and / or a single-fluid nozzle is used for spraying the coagulant solution.

[0009] [2] The method for producing an agglomerate according to [1], wherein in the contact step, a single-fluid nozzle is used to spray the coagulant solution.

[0010] [3] The method for producing an aggregate according to [1] or [2], wherein the droplets of the coagulant solution have a volume average droplet diameter of 1 μm to 100 μm.

[0011] [4] The method for producing an aggregate according to any one of [1] to [3], wherein the concentration of the polymer fine particles in the latex is 10% by weight to 55% by weight based on 100% by weight of the latex.

[0012] [5] The method for producing an aggregate according to any one of [1] to [4], wherein the amount of the coagulant sprayed is 1 to 30 parts by weight per 100 parts by weight of the total amount of the polymer microparticles sprayed and dropped.

[0013] [6] The method for producing an aggregate according to any one of [1] to [5], wherein the polymer fine particles have an elastomer and a graft portion graft-bonded to the elastomer.

[0014] [7] The method for producing an aggregate according to [6], wherein the elastic body contains at least one rubber selected from the group consisting of diene rubber, (meth)acrylate rubber, and organosiloxane rubber.

[0015] [8] The method for producing an aggregate according to [6] or [7], wherein the graft portion is composed of a polymer containing, as a structural unit, a structural unit derived from one or more monomers selected from the group consisting of an aromatic vinyl monomer, a vinyl cyan monomer, and a (meth)acrylate monomer.

[0016] [9] A method for producing a powder of polymer microparticles, comprising: a recovery step of recovering the agglomerates obtained by the agglomerate production method according to any one of [1] to [8]; and a drying step of drying the recovered agglomerates. [Effects of the Invention]

[0017] According to one aspect of the present invention, it is possible to provide a method for producing an agglomerate and a method for producing a powder or granular material, in which the recovery rate of the agglomerate of polymer fine particles from a latex of the polymer fine particles is improved. DETAILED DESCRIPTION OF THE INVENTION

[0018] One embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to the respective configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by appropriately combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic literature and patent documents described in this specification are incorporated herein by reference. Furthermore, unless otherwise specified in this specification, the term "A to B" representing a numerical range means "greater than or equal to A (including and greater than A) and less than or equal to B (including and less than B)."

[0019] 1. Technical Concept of One Embodiment of the Present Invention A known method for producing polymer microparticle aggregates and powder particles from a latex of polymer microparticles (hereinafter sometimes referred to as latex) involves spraying and / or dropping the polymer microparticle latex into a gas phase, agglomerating the polymer microparticles by bringing the droplets of the polymer microparticle latex into contact with droplets of a coagulant solution sprayed into the gas phase, obtaining polymer microparticle aggregates, and drying the aggregates to obtain powder particles.

[0020] Patent Document 1 describes spraying a latex of polymer fine particles and a coagulant solution from a nozzle. Conventionally, in spraying such latex and coagulant solution, both the latex and the coagulant solution are sprayed vertically, and a two-fluid nozzle is used for spraying the coagulant solution.

[0021] The technology of Patent Document 1 required a large device, particularly one equipped with a vertically long container. Therefore, the present inventors first investigated a method for obtaining aggregates and powders of polymer microparticles using a smaller device than conventional devices, particularly one equipped with a container shorter in the vertical direction than conventional devices. During the course of their intensive investigations, the present inventors focused on the frequency of contact between droplets of latex containing polymer microparticles and droplets of coagulant solution. Specifically, the present inventors suspected that spraying both the polymer microparticle latex and the coagulant solution vertically reduced the frequency of contact between the polymer microparticles and the coagulant. The present inventors then conducted extensive research into methods for increasing the frequency of contact between the polymer microparticles and the coagulant. As a result, the present inventors discovered a novel finding that spraying and / or dripping the polymer microparticle latex vertically and spraying the coagulant solution horizontally increased the frequency of contact between the polymer microparticles and the coagulant compared to spraying both the polymer microparticle latex and the coagulant solution vertically.

[0022] However, when the present inventors tried spraying and / or dropping latex vertically and spraying coagulant solution horizontally, they encountered a problem that had occurred in the past: adhesion of aggregates to the inner wall surface of the coagulation bath (a container including an area where latex and coagulant solution are sprayed and brought into contact with each other). To solve this problem, the present inventors conducted further intensive research. As a result, they surprisingly found that when the amount of gas sprayed together with the coagulant solution was less than a predetermined amount when spraying the coagulant solution horizontally, adhesion of aggregates to the inner wall surface of the coagulation bath could be reduced even more than in the past.

[0023] The present inventors speculated that the adhesion of aggregates to the inner wall surface of the coagulation tank was reduced by spraying the coagulant solution horizontally and by controlling the amount of gas sprayed together with the coagulant solution to less than a predetermined amount. However, the present invention is not limited to this speculation. Furthermore, the present inventors newly discovered that spraying and / or dripping polymer microparticle latex in a vertical direction, spraying the coagulant solution horizontally, and controlling the amount of gas sprayed together with the coagulant solution to less than a predetermined amount improved the recovery rate of polymer microparticle aggregates. This is believed to be due to the reduced adhesion of aggregates to the inner wall surface of the coagulation tank and the increased frequency of contact between the polymer microparticle latex and the coagulant.

[0024] That is, the present inventors have conducted extensive research with the aim of providing a novel method for producing agglomerates and a novel method for producing powders and granules, which use smaller equipment than conventional methods and have an improved recovery rate of agglomerates of polymer microparticles from latex of polymer microparticles compared to conventional methods. As a result, the present inventors have newly discovered the following, which has led to the completion of the present invention: the recovery rate of agglomerates from latex of polymer microparticles can be improved by a method for producing agglomerates in which a latex of polymer microparticles is sprayed and / or dropped in a vertical direction and the coagulant solution is sprayed in a horizontal direction to bring the latex droplets into contact with the coagulant solution droplets, and the coagulant solution is sprayed using a two-fluid nozzle with an air flow rate set to less than 60 L / min and / or a single-fluid nozzle is used for spraying the coagulant solution.

[0025] Furthermore, the present inventors have newly discovered the following: when a latex of polymer fine particles is sprayed and / or dropped in a vertical direction, and the coagulant solution is sprayed in a horizontal direction, and the amount of gas sprayed together with the coagulant solution is less than a predetermined amount, the obtained aggregates have a high circularity (close to 1), and the powder particles obtained by drying the aggregates have a high circularity (close to 1) and a large bulk density.

[0026] 2. Method for producing aggregates A method for producing an aggregate according to one embodiment of the present invention includes a contacting step of vertically spraying and / or dropping a latex of polymer microparticles and horizontally spraying the coagulant solution to bring the latex droplets into contact with the coagulant solution droplets, wherein the coagulant solution is sprayed using a two-fluid nozzle with an air flow rate set to less than 60 L / min and / or the coagulant solution is sprayed using a single-fluid nozzle. Hereinafter, the method for producing an aggregate according to one embodiment of the present invention may be referred to as "the present method for producing an aggregate."

[0027] In this specification, the term "air flow rate" refers to the amount (volume) of gas sprayed per unit time, and can be set appropriately depending on the specifications of the two-fluid nozzle used. The gas refers to the gas sprayed together with the coagulant solution, such as air, nitrogen, or carbon dioxide.

[0028] In this specification, a latex of polymer microparticles may be simply referred to as a "latex," an aggregate of polymer microparticles may be simply referred to as an "aggregate," and an aggregate of polymer microparticles obtained by the present method for producing an aggregate may be hereinafter referred to as the "present aggregate." Furthermore, a powder of polymer microparticles may be simply referred to as a "powder."

[0029] Furthermore, in this specification, "spraying" a liquid (e.g., latex or coagulant solution) means spraying (spraying in a mist) the liquid in the form of droplets (microdroplets) smaller in diameter than the diameter of the nozzle outlet (hole) through which the liquid is sprayed, by methods such as pressurizing the liquid or subjecting it to ultrasonic treatment, and "dripping" a liquid (e.g., latex) means spraying the liquid as droplets with a diameter similar to the diameter of the nozzle outlet (hole) through which the liquid is sprayed, without any special treatment. Note that when a liquid is sprayed using a two-fluid nozzle, even if the liquid itself to be sprayed is not pressurized, the liquid is considered to be "sprayed" when a substance other than the liquid (e.g., a gas) is simultaneously sprayed under pressure, thereby spraying the liquid in the form of microdroplets.

[0030] Furthermore, in this specification, the term "vertical direction" refers to the direction of gravity and is also referred to as the vertically downward direction. Furthermore, in this specification, when a liquid (e.g., latex) is "sprayed and / or dripped vertically," it does not necessarily mean that the liquid is sprayed and / or dripped in a completely vertical direction; for example, the liquid may be sprayed and / or dripped in a direction tilted within a range of 15°, 10°, or 5° from the vertical direction. In other words, in this specification, "sprayed and / or dripped vertically" is a concept that includes such spraying and / or dripping at an angle relative to the vertical direction.

[0031] Furthermore, in this specification, the term "horizontal direction" refers to a direction perpendicular to the vertical direction. Furthermore, in this specification, "spraying a liquid (e.g., a coagulant solution) in a horizontal direction" does not necessarily mean that the liquid is sprayed in a completely horizontal direction. For example, the liquid may be sprayed in a direction tilted within a range of 15°, 10°, or 5° from the horizontal direction. In other words, the term "spraying in a horizontal direction" in this specification encompasses the spraying of the liquid at an angle relative to the horizontal direction. In this specification, the direction in which the liquid is sprayed and / or dripped can also be said to be the direction in which the nozzle of the nozzle spraying and / or dripping the liquid faces. In other words, the direction in which the liquid is sprayed and / or dripped can be adjusted by adjusting the direction in which the nozzle of the nozzle spraying and / or dripping the liquid faces.

[0032] In this method for producing agglomerates, the latex is sprayed and / or dripped vertically, and the coagulant solution is sprayed horizontally, thereby increasing the frequency of contact between the latex and the coagulant solution. This promotes aggregation of the polymer microparticles, improving the recovery rate of the polymer microparticle agglomerates and increasing the circularity of the agglomerates (approaching 1). The powder or granules obtained by drying the agglomerates have a higher circularity (approaching 1) and a higher bulk density. Furthermore, by using a two-fluid nozzle with an air flow rate set to less than 60 L / min and / or a single-fluid nozzle to spray the coagulant solution, it is possible to reduce the turbulence of the airflow inside the container (coagulation tank), which can occur when the coagulant solution is sprayed horizontally with gas. This reduces the amount of polymer microparticle agglomerates adhering to the inner wall of the container, thereby improving the recovery rate of the polymer microparticle agglomerates. The circularity of the polymer microparticle agglomerates adhering to the inner wall of the container decreases, thereby reducing the circularity and bulk density of the resulting powder or granules. Therefore, by using a two-fluid nozzle with an air flow rate set to less than 60 L / min and / or a single-fluid nozzle to spray the coagulant solution, it is possible to obtain agglomerates with a high circularity (close to 1) and powder or granules with a high circularity (close to 1) and a large bulk density. In other words, the present agglomerate manufacturing method, by having the above-mentioned configuration, has the advantage of improving the recovery rate of the agglomerates, the circularity of the agglomerates, and the circularity and bulk density of the powder or granules.

[0033] Below, the raw materials (components) and equipment used in the method for producing the present aggregate will be described in detail, followed by a description of the steps in the method for producing the present aggregate.

[0034] (2-1. Latex) As used herein, "latex" refers to a solution containing a solvent and polymer microparticles, with the polymer microparticles dispersed in the solvent. "Latex" refers to latex containing polymer microparticles, and can also be called a "suspension of polymer microparticles." The solvent for latex is not particularly limited, but water is an example. Latex using water as the solvent is sometimes called "aqueous latex," and can also be called an "aqueous suspension of polymer microparticles." In the latex solvent, the polymer microparticles are preferably dispersed in the form of primary particles.

[0035] The concentration of the polymer microparticles in the latex is not particularly limited, but is preferably 10% to 55% by weight, more preferably 10% to 45% by weight, and even more preferably 25% to 40% by weight, based on 100% by weight of the latex. A concentration of the polymer microparticles in the latex of 10% by weight or more is preferred because the bulk density of the aggregates increases. A concentration of the polymer microparticles in the latex of 55% by weight or less is preferred because the latex can be smoothly sprayed and / or dropped from a nozzle. The concentration of the polymer microparticles in the latex can be adjusted by appropriately changing the amount of solvent (e.g., water) and the amount of monomer used in the production process of the polymer microparticles.

[0036] The concentration of the polymer microparticles in the latex can be calculated by, for example, placing 0.5 g of latex in a hot air convection dryer at 120°C for 3 hours to evaporate the water, measuring the weight W (g) of the residue (solid content) after drying, dividing the obtained value by 0.5 g, the weight of the latex before drying, and multiplying the obtained value by 100. The residue after drying, i.e., the solid content, mainly contains polymer microparticles but may also contain components other than polymer microparticles. Therefore, the "concentration of polymer microparticles in the latex" calculated by the above-mentioned method can also be rephrased as the "concentration of solid content in the latex."

[0037] The viscosity of the latex at 25°C is not particularly limited, but is preferably 10 mPa·s or more, more preferably 15 mPa·s or more, and even more preferably 20 mPa·s or more. The upper limit of the viscosity of the latex at 25°C is not particularly limited, but is preferably 100 mPa·s or less, more preferably 50 mPa·s or less, and even more preferably 30 mPa·s or less.

[0038] A latex having a viscosity of 10 mPa·s or higher at 25°C has the advantage that the amount of fine powder generated as a by-product during the production of powder particles from the aggregates obtained by the present method for producing aggregates is likely to be reduced. Furthermore, a latex having a viscosity of 100 mPa·s or lower at 25°C has the advantage that the aggregates obtained by the present method for producing aggregates can be smoothly sprayed and / or dropped from a nozzle of an apparatus (e.g., the first nozzle described below). The viscosity of the latex can be adjusted by appropriately changing the solids concentration in the latex (the concentration of polymer microparticles in the latex) and, if the latex contains a thickener, the content of the thickener in the latex.

[0039] The viscosity of latex can be measured at 25°C using a viscometer such as a Cannon-Fenske, Cannon-Fenske reverse flow, Ubbelohde, or Brookfield (B-type viscometer). The method for measuring the viscosity of latex will be described in detail in the Examples below.

[0040] The latex containing polymer microparticles can be produced by a known method, such as emulsion polymerization of polymer microparticles, or a method of suspending polymer microparticles and an emulsifier in a solvent, etc. The emulsion polymerization of polymer microparticles will be described in detail later in the section (2-3. Production method of polymer microparticles).

[0041] (2-2. Polymer microparticles) The polymer microparticles are not particularly limited in other aspects as long as they are microparticles obtained by polymerization.

[0042] (graft area) The polymer microparticles preferably have a graft moiety. In this specification, the term "graft moiety" refers to a polymer graft-bonded to an arbitrary polymer. The polymer microparticles having a graft moiety can also be called a graft copolymer. In other words, the polymer microparticles are preferably graft copolymers. When the polymer microparticles are graft copolymers, there is an advantage in that the polymer microparticles can exhibit suitable behavior in the present method for producing an aggregate and the method for producing a powder or granule described below.

[0043] The graft moiety is preferably a polymer containing, as a structural unit, a structural unit derived from one or more monomers selected from the group consisting of aromatic vinyl monomers, vinyl cyan monomers, and (meth)acrylate monomers. A graft moiety having the above structure can fulfill various roles. Examples of "various roles" include (i) improving the compatibility between polymer microparticles and a matrix resin, (ii) improving the dispersibility of polymer microparticles in a matrix resin, and (iii) enabling polymer microparticles to be dispersed in the form of primary particles in a resin composition containing a matrix resin and polymer microparticles (hereinafter simply referred to as "resin composition"), or in a molded or cured product thereof.

[0044] Specific examples of aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, and divinylbenzene.

[0045] Specific examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile.

[0046] Specific examples of the (meth)acrylate monomer include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hydroxyethyl (meth)acrylate, and hydroxybutyl (meth)acrylate. In this specification, the term "(meth)acrylate" refers to acrylate and / or methacrylate.

[0047] The one or more monomers selected from the group consisting of the aromatic vinyl monomer, the vinyl cyan monomer, and the (meth)acrylate monomer may be used alone or in combination of two or more.

[0048] The graft portion preferably contains, as structural units, structural units derived from aromatic vinyl monomers, structural units derived from vinyl cyan monomers, and structural units derived from (meth)acrylate monomers in a total amount of 10 to 95% by weight, more preferably 30 to 92% by weight, even more preferably 50 to 90% by weight, particularly preferably 60 to 87% by weight, and most preferably 70 to 85% by weight, based on 100% by weight of the graft portion.

[0049] The graft portion preferably contains, as a structural unit, a structural unit derived from a monomer having a reactive group. The monomer having a reactive group is preferably a monomer having one or more reactive groups selected from the group consisting of an epoxy group, an oxetane group, a hydroxyl group, an amino group, an imide group, a carboxylic acid group, a carboxylic anhydride group, a cyclic ester, a cyclic amide, a benzoxazine group, and a cyanate ester group, more preferably a monomer having one or more reactive groups selected from the group consisting of an epoxy group, a hydroxyl group, and a carboxylic acid group, and most preferably a monomer having an epoxy group. This configuration allows the graft portion of the polymer microparticles to be chemically bonded to the matrix resin in the resin composition. This allows the polymer microparticles to be maintained in a well-dispersed state without agglomeration in the resin composition, or in a molded or cured product thereof.

[0050] Specific examples of the monomer having an epoxy group include glycidyl group-containing vinyl monomers such as glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and allyl glycidyl ether.

[0051] Specific examples of monomers having a hydroxyl group include: (i) hydroxy linear alkyl (meth)acrylates (particularly, hydroxy linear C1-6 alkyl (meth)acrylates) such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; (ii) caprolactone-modified hydroxy (meth)acrylates; (iii) hydroxy branched alkyl (meth)acrylates such as α-(hydroxymethyl)methyl acrylate and α-(hydroxymethyl)ethyl acrylate; and (iv) hydroxyl group-containing (meth)acrylates such as mono(meth)acrylates of polyester diols (particularly saturated polyester diols) obtained from divalent carboxylic acids (such as phthalic acid) and dihydric alcohols (such as propylene glycol).

[0052] Specific examples of the monomer having a carboxylic acid group include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid. The above-mentioned monocarboxylic acids are preferably used as the monomer having a carboxylic acid group.

[0053] The above-mentioned monomers having a reactive group may be used alone or in combination of two or more.

[0054] The graft portion preferably contains 0.5 to 90.0 wt % of structural units derived from monomers having reactive groups, based on 100 wt % of the graft portion, more preferably 1.0 to 50.0 wt %, even more preferably 2.0 to 35.0 wt %, and particularly preferably 3.0 to 20.0 wt %. When the graft portion contains (i) 0.5 wt % or more of structural units derived from monomers having reactive groups, based on 100 wt % of the graft portion, the resulting resin composition can provide a molded article or cured product having sufficient impact resistance, and (ii) when the graft portion contains 90.0 wt % or less of the structural units, the resulting resin composition can provide a molded article or cured product having sufficient impact resistance, and the storage stability of the resin composition is excellent.

[0055] The structural unit derived from a monomer having a reactive group is preferably contained in the graft portion, and more preferably contained only in the graft portion.

[0056] The graft moiety may contain a structural unit derived from a polyfunctional monomer as a structural unit. When the graft moiety contains a structural unit derived from a polyfunctional monomer, it has the following advantages: (i) swelling of the polymer fine particles in the resin composition can be prevented, (ii) the viscosity of the resin composition is reduced, which tends to improve the handleability of the resin composition, and (iii) the dispersibility of the polymer fine particles in the matrix resin is improved.

[0057] When the graft portion does not contain a structural unit derived from a polyfunctional monomer, the resulting resin composition can provide a molded article or cured product that is more excellent in toughness and impact resistance than when the graft portion contains a structural unit derived from a polyfunctional monomer.

[0058] A polyfunctional monomer can also be said to be a monomer having two or more radically polymerizable reactive groups in the same molecule. The radically polymerizable reactive group is preferably a carbon-carbon double bond. Examples of polyfunctional monomers include (meth)acrylates having an ethylenically unsaturated double bond, such as allyl alkyl (meth)acrylates and allyloxy alkyl (meth)acrylates, and do not include butadiene. Examples of monomers having two (meth)acrylic groups include ethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and polyethylene glycol di(meth)acrylates. Examples of the polyethylene glycol di(meth)acrylates include triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and polyethylene glycol (600) di(meth)acrylate. Examples of monomers having three (meth)acrylic groups include alkoxylated trimethylolpropane tri(meth)acrylates, glycerol propoxy tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate. Examples of the alkoxylated trimethylolpropane tri(meth)acrylates include trimethylolpropane tri(meth)acrylate and trimethylolpropane triethoxy tri(meth)acrylate. Further, examples of monomers having four (meth)acrylic groups include pentaerythritol tetra(meth)acrylate and ditrimethylolpropane tetra(meth)acrylate.Further, examples of monomers having five (meth)acrylic groups include dipentaerythritol penta(meth)acrylate.Further, examples of monomers having six (meth)acrylic groups include ditrimethylolpropane hexa(meth)acrylate.Polyfunctional monomers also include diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, and the like.

[0059] Among the above-mentioned polyfunctional monomers, polyfunctional monomers that can be preferably used for polymerization of the graft portion include allyl methacrylate, ethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and polyethylene glycol di(meth)acrylates. These polyfunctional monomers may be used alone or in combination of two or more.

[0060] The graft portion preferably contains 1 to 20% by weight, and more preferably 5 to 15% by weight, of structural units derived from polyfunctional monomers, based on 100% by weight of the graft portion.

[0061] In the polymerization of the graft portion, the above-mentioned monomers may be used alone or in combination of two or more. Furthermore, the graft portion may contain, as a constituent unit, a constituent unit derived from another monomer in addition to the constituent unit derived from the above-mentioned monomer.

[0062] The graft portion is preferably a polymer graft-bonded to an elastomer, which will be described later.

[0063] (Glass transition temperature of the grafted portion) The glass transition temperature of the graft portion is not particularly limited, but is preferably 0°C or higher, more preferably 30°C or higher, more preferably 50°C or higher, and more preferably 60°C or higher. Polymer microparticles having a glass transition temperature of 60°C or higher at the graft portion can also be called hard grade. The use of hard grade polymers has the advantage of being able to reduce the amount of hard non-elastomeric polymer latex used in the heat treatment step and drying step described below. The glass transition temperature of the graft portion may be 65°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, or 100°C or higher. The upper limit of the glass transition temperature of the graft portion is not particularly limited, but is preferably 190°C or lower, more preferably 160°C or lower, more preferably 140°C or lower, and more preferably 120°C or lower.

[0064] The Tg of the graft portion can be determined by the composition of the structural units contained in the graft portion, etc. In other words, the Tg of the resulting graft portion can be adjusted by changing the composition of the monomers used when producing (polymerizing) the graft portion.

[0065] When the graft portion is a copolymer of two or more monomers and the monomers used in the production (polymerization) of the graft portion are known, the glass transition temperature Tg of the graft portion can be calculated by the FOX formula (Formula 1) shown below.

[0066] 1 / Tg=w1 / Tg1+w2 / Tg2+···+wn / Tgn (Equation 1) Here, Tg1, Tg2, ..., Tgn are the Tg(K) of the homopolymer of the components constituting the graft portion (i.e., the monomers used in the production of the graft portion) 1, 2, ..., n, respectively, and w1, w2, ..., wn are the weight fractions of the components constituting the graft portion (i.e., the monomers used in the production of the graft portion) 1, 2, ..., n, respectively. The Tg of the homopolymer can be determined, for example, from the Polymer Handbook, Fourth Edition (edited by J. Brandup et al., Jphn Wiley & Sons, Inc.). For novel polymers, the peak temperature of the loss tangent (tan δ) measured by viscoelasticity measurement (shear method, measurement frequency: 1 Hz) can be used as the Tg.

[0067] When the monomer used in the production (polymerization) of the grafted portion is unknown, the Tg of the grafted portion can be determined by viscoelasticity measurements using a flat plate made of polymer microparticles. Specifically, Tg can be measured as follows: (1) Dynamic viscoelasticity measurements are performed under tensile conditions on a flat plate made of polymer microparticles using a dynamic viscoelasticity measuring device (e.g., DVA-200, manufactured by IT Measurement & Control Co., Ltd.) to obtain a tan δ graph; (2) The peak temperature of tan δ in the obtained tan δ graph is taken as the glass transition temperature. Here, if multiple peaks are obtained in the tan δ graph, the highest peak temperature is taken as the glass transition temperature of the grafted portion.

[0068] (Modification of the graft part) In one embodiment of the present invention, the graft portion may consist of only one type of graft portion having structural units of the same composition, or may consist of multiple types of graft portions each having a structural unit of a different composition.

[0069] When the polymer microparticles are multistage polymers, the graft portion may cover at least a portion of any polymer (e.g., the elastomer described below), or may cover the entirety of any polymer. When the polymer microparticles are multistage polymers, a portion of the graft portion may penetrate into the interior of any polymer. It is preferable that at least a portion of the graft portion covers at least a portion of the elastomer. In other words, it is preferable that at least a portion of the graft portion is present on the outermost side of the polymer microparticles.

[0070] When the polymer microparticles are multistage polymers, any polymer (e.g., the elastomer described below) and the graft moiety may form a layer structure. For example, one embodiment of the present invention is one in which the elastomer forms the innermost layer (also referred to as the core layer) and a layer of the graft moiety is formed as the outermost layer (also referred to as the shell layer) outside the elastomer. A structure in which the elastomer forms the core layer and the graft moiety forms the shell layer can also be referred to as a core-shell structure. Thus, polymer microparticles in which the elastomer and the graft moiety form a layer structure (core-shell structure) can also be referred to as a multilayer polymer or a core-shell polymer. That is, in one embodiment of the present invention, the polymer microparticles may be multistage polymers and / or multilayer polymers or core-shell polymers. However, as long as they have graft moieties, the polymer microparticles are not limited to the above structure.

[0071] (elastic body) The polymer microparticles preferably further comprise an elastomer. The graft moiety is preferably a polymer graft-bonded to the elastomer. That is, the polymer microparticles are more preferably rubber-containing graft copolymers having an elastomer and a graft moiety graft-bonded to the elastomer. Hereinafter, one embodiment of the present invention will be described using an example in which the polymer microparticles are rubber-containing graft copolymers.

[0072] The elastic body preferably contains one or more rubbers selected from the group consisting of diene rubbers, (meth)acrylate rubbers, and organosiloxane rubbers. The elastic body may contain natural rubber in addition to the above-mentioned rubbers. The elastic body can also be referred to as an elastic portion or rubber particles.

[0073] The case where the elastomer contains a diene rubber (Case A) will be described. In Case A, the resulting resin composition can provide a molded article or cured product that is excellent in toughness and impact resistance. A molded article or cured product that is excellent in toughness and / or impact resistance can also be said to be a molded article or cured product that is excellent in durability.

[0074] The diene rubber is an elastomer containing, as structural units, structural units derived from a diene monomer. The diene monomer can also be referred to as a conjugated diene monomer. In Case A, the diene rubber may contain, based on 100% by weight of structural units, 50 to 100% by weight of structural units derived from a diene monomer and 0 to 50% by weight of structural units derived from a vinyl monomer other than a diene monomer copolymerizable with the diene monomer. In Case A, the diene rubber may contain, as structural units, structural units derived from a (meth)acrylate monomer in an amount less than the structural units derived from the diene monomer.

[0075] Examples of the diene monomer include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2-chloro-1,3-butadiene, etc. These diene monomers may be used alone or in combination of two or more.

[0076] Examples of vinyl monomers other than diene monomers copolymerizable with diene monomers (hereinafter also referred to as vinyl monomer A) include vinyl arenes such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; vinyl carboxylic acids such as acrylic acid and methacrylic acid; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride, vinyl bromide, and chloroprene; vinyl acetate; alkenes such as ethylene, propylene, butylene, and isobutylene; and polyfunctional monomers such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene. The vinyl monomer A may be used alone or in combination of two or more. Among the vinyl monomers A, styrene is particularly preferred. In the diene rubber in Case A, the structural unit derived from the vinyl monomer A is an optional component. In case A, the diene rubber may be composed solely of structural units derived from diene monomers.

[0077] In Case A, the diene rubber is preferably butadiene rubber (also called polybutadiene rubber) consisting of structural units derived from 1,3-butadiene, or butadiene-styrene rubber (also called polystyrene-butadiene), which is a copolymer of 1,3-butadiene and styrene, with butadiene rubber being more preferred. According to this configuration, the polymer microparticles containing diene rubber can more effectively exhibit the desired effects. Furthermore, butadiene-styrene rubber is more preferred in that the transparency of the resulting molded or cured product can be increased by adjusting the refractive index.

[0078] The case where the elastomer contains a (meth)acrylate rubber (Case B) will be explained. In Case B, a wide range of polymer designs for the elastomer are possible by combining a variety of monomers.

[0079] The (meth)acrylate rubber is an elastomer containing, as structural units, structural units derived from (meth)acrylate monomers. In Case B, the (meth)acrylate rubber may contain, based on 100% by weight of structural units, 50 to 100% by weight of structural units derived from (meth)acrylate monomers and 0 to 50% by weight of structural units derived from vinyl monomers other than (meth)acrylate monomers copolymerizable with the (meth)acrylate monomers. In Case B, the (meth)acrylate rubber may contain, as structural units, structural units derived from diene monomers in an amount less than the structural units derived from the (meth)acrylate monomers.

[0080] Examples of the (meth)acrylate monomer include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; aromatic ring-containing (meth)acrylates such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; Examples of suitable (meth)acrylate monomers include hydroxyalkyl (meth)acrylates such as acrylate; glycidyl (meth)acrylates such as glycidyl (meth)acrylate and glycidyl alkyl (meth)acrylate; alkoxyalkyl (meth)acrylates; allyl alkyl (meth)acrylates such as allyl (meth)acrylate and allyl alkyl (meth)acrylate; and polyfunctional (meth)acrylates such as monoethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. These (meth)acrylate monomers may be used alone or in combination of two or more. Among these (meth)acrylate monomers, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred, with butyl (meth)acrylate being more preferred.

[0081] In Case B, the (meth)acrylate rubber is preferably one or more selected from the group consisting of methyl (meth)acrylate rubber, ethyl (meth)acrylate rubber, butyl (meth)acrylate rubber, and 2-ethylhexyl (meth)acrylate rubber, with methyl (meth)acrylate rubber and butyl (meth)acrylate rubber being more preferred. The methyl (meth)acrylate rubber is a rubber made up of structural units derived from methyl (meth)acrylate, the ethyl (meth)acrylate rubber is a rubber made up of structural units derived from ethyl (meth)acrylate, the butyl (meth)acrylate rubber is a rubber made up of structural units derived from butyl (meth)acrylate, and the 2-ethylhexyl (meth)acrylate rubber is a rubber made up of structural units derived from 2-ethylhexyl (meth)acrylate. This configuration results in a lower glass transition temperature (Tg) of the elastomer, resulting in polymer microparticles and resin compositions with a low Tg. As a result, (i) the resulting resin composition can provide a molded article or cured product having excellent toughness, and (ii) the viscosity of the resin composition can be reduced.

[0082] Examples of vinyl monomers other than (meth)acrylate monomers copolymerizable with (meth)acrylate monomers (hereinafter also referred to as vinyl monomer B) include the monomers listed for vinyl monomer A. Vinyl monomer B may be used alone or in combination of two or more. Among vinyl monomers B, styrene is particularly preferred. In the (meth)acrylate rubber in Case B, the structural unit derived from vinyl monomer B is an optional component. In Case B, the (meth)acrylate rubber may be composed only of structural units derived from (meth)acrylate monomers.

[0083] The case where the elastomer contains an organosiloxane-based rubber (Case C) will be described below. In Case C, the resulting resin composition can provide a molded article or cured product that has sufficient heat resistance and excellent impact resistance at low temperatures.

[0084] Examples of organosiloxane rubbers include (i) organosiloxane polymers composed of alkyl or aryl di-substituted silyloxy units, such as dimethylsilyloxy, diethylsilyloxy, methylphenylsilyloxy, diphenylsilyloxy, and dimethylsilyloxy-diphenylsilyloxy, and (ii) organosiloxane polymers composed of alkyl or aryl mono-substituted silyloxy units, such as organohydrogensilyloxy in which some of the alkyl groups in the side chains are substituted with hydrogen atoms. These organosiloxane polymers may be used alone or in combination of two or more.

[0085] In this specification, a polymer composed of dimethylsilyloxy units is referred to as dimethylsilyloxy rubber, a polymer composed of methylphenylsilyloxy units is referred to as methylphenylsilyloxy rubber, and a polymer composed of dimethylsilyloxy units and diphenylsilyloxy units is referred to as dimethylsilyloxy-diphenylsilyloxy rubber. In Case C, the organosiloxane rubber is preferably one or more selected from the group consisting of dimethylsilyloxy rubber, methylphenylsilyloxy rubber, and dimethylsilyloxy-diphenylsilyloxy rubber, because (i) the resulting resin composition containing the granules can provide a molded article or cured product with excellent heat resistance, and (ii) dimethylsilyloxy rubber is more preferred because it is easily available and economical.

[0086] In Case C, the polymer microparticles preferably contain 80% by weight or more, and more preferably 90% by weight or more, of the organosiloxane rubber relative to 100% by weight of the elastomer contained in the polymer microparticles. According to this configuration, the resulting resin composition can provide a molded article or cured product with excellent heat resistance.

[0087] The elastomer may further contain an elastomer other than diene rubber, (meth)acrylate rubber, and organosiloxane rubber. Examples of the elastomer other than diene rubber, (meth)acrylate rubber, and organosiloxane rubber include natural rubber.

[0088] In one embodiment of the present invention, the elastomer is preferably one or more selected from the group consisting of butadiene rubber, butadiene-styrene rubber, butadiene-(meth)acrylate rubber, ethyl (meth)acrylate rubber, butyl (meth)acrylate rubber, 2-ethylhexyl (meth)acrylate rubber, dimethylsilyloxy rubber, methylphenylsilyloxy rubber, and dimethylsilyloxy-diphenylsilyloxy rubber, and more preferably one or more selected from the group consisting of butadiene rubber, butadiene-styrene rubber, butyl (meth)acrylate rubber, and dimethylsilyloxy rubber.

[0089] (elastic cross-linked structure) From the viewpoint of maintaining the dispersion stability of the polymer microparticles in the thermosetting resin, it is preferable that a crosslinked structure be introduced into the elastomer. A commonly used method can be used to introduce a crosslinked structure into the elastomer, and examples thereof include the following methods. Specifically, in the production of the elastomer, a method can be used in which a crosslinkable monomer such as a polyfunctional monomer and / or a mercapto group-containing compound is mixed with a monomer capable of constituting the elastomer, followed by polymerization. In this specification, the production of a polymer such as an elastomer is also referred to as polymerizing a polymer.

[0090] Other methods for introducing a crosslinked structure into organosiloxane rubber include: (A) using a polyfunctional alkoxysilane compound in combination with other materials when polymerizing organosiloxane rubber; (B) introducing reactive groups (e.g., (i) mercapto groups and (ii) reactive vinyl groups) into organosiloxane rubber, and then adding (i) an organic peroxide or (ii) a polymerizable vinyl monomer to the resulting reaction product to cause a radical reaction; and (C) mixing a crosslinkable monomer such as a polyfunctional monomer and / or a mercapto group-containing compound with other materials when polymerizing organosiloxane rubber, followed by polymerization.

[0091] Examples of polyfunctional monomers include the polyfunctional monomers exemplified in the above section (Graft portion). Among these polyfunctional monomers, polyfunctional monomers that can be preferably used to introduce a crosslinked structure into the elastomer include allyl methacrylate, ethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate (e.g., 1,3-butylene glycol dimethacrylate), butanediol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and polyethylene glycol di(meth)acrylates. These polyfunctional monomers may be used alone or in combination of two or more.

[0092] (glass transition temperature of elastic body) The glass transition temperature of the elastomer is preferably 80°C or lower, more preferably 70°C or lower, more preferably 60°C or lower, more preferably 50°C or lower, more preferably 40°C or lower, more preferably 30°C or lower, more preferably 20°C or lower, more preferably 10°C or lower, and more preferably 0°C or lower. The glass transition temperature of the elastomer may be -10°C or lower, -20°C or lower, -40°C or lower, -45°C or lower, -50°C or lower, -55°C or lower, -60°C or lower, -65°C or lower, -70°C or lower, -75°C or lower, -80°C or lower, -85°C or lower, -90°C or lower, -95°C or lower, or -100°C or lower. In this specification, "glass transition temperature" may also be referred to as "Tg." This configuration allows for the production of polymer microparticles having a low Tg and resin compositions having a low Tg. As a result, the resulting resin composition can provide a molded article or cured product having excellent toughness. Furthermore, this configuration can further reduce the viscosity of the resulting resin composition.

[0093] The glass transition temperature (Tg) of the elastomer can be calculated by the above-mentioned FOX formula (Formula 1), except that "graft portion of polymer microparticles" is replaced with "elastic body of polymer microparticles."

[0094] When the monomer used in the production (polymerization) of an elastomer is unknown, the Tg of the elastomer can be determined by performing viscoelasticity measurements using a flat plate made of polymer microparticles. Specifically, Tg can be measured as follows: (1) Dynamic viscoelasticity measurements are performed under tensile conditions on a flat plate made of polymer microparticles using a dynamic viscoelasticity measuring device (e.g., DVA-200, manufactured by IT Measurement & Control Co., Ltd.) to obtain a tan δ graph; (2) The peak temperature of tan δ in the obtained tan δ graph is taken as the glass transition temperature. Here, if multiple peaks are obtained in the tan δ graph, the lowest peak temperature is taken as the glass transition temperature of the elastomer.

[0095] On the other hand, since this can prevent a decrease in the modulus of elasticity (rigidity) of the resulting molded body or cured product, i.e., a molded body or cured product having sufficient modulus of elasticity (rigidity), the Tg of the elastomer is preferably greater than 0°C, more preferably 20°C or greater, even more preferably 50°C or greater, particularly preferably 80°C or greater, and most preferably 120°C or greater.

[0096] The Tg of an elastomer can be determined by the composition of the structural units contained in the elastomer, etc. In other words, the Tg of the resulting elastomer can be adjusted by changing the composition of the monomers used when producing (polymerizing) the elastomer.

[0097] Here, when a homopolymer is prepared by polymerizing only one type of monomer, a group of monomers that provides a homopolymer having a Tg greater than 0°C is referred to as monomer group a. Furthermore, when a homopolymer is prepared by polymerizing only one type of monomer, a group of monomers that provides a homopolymer having a Tg less than 0°C is referred to as monomer group b. An elastomer containing 50 to 100 wt% (more preferably, 65 to 99 wt%) of structural units derived from at least one monomer selected from monomer group a and 0 to 50 wt% (more preferably, 1 to 35 wt%) of structural units derived from at least one monomer selected from monomer group b is referred to as elastomer G. Elastomer G has a Tg greater than 0°C. Furthermore, when the elastomer contains elastomer G, the resulting resin composition can provide a molded or cured product with sufficient rigidity.

[0098] It is also preferable that a crosslinked structure be introduced into the elastic body when the Tg of the elastic body is higher than 0° C. Methods for introducing a crosslinked structure include the methods described above.

[0099] Monomers that can be included in the monomer group a include, but are not limited to, unsubstituted vinyl aromatic compounds such as styrene and 2-vinylnaphthalene; vinyl-substituted aromatic compounds such as α-methylstyrene; ring-alkylated vinyl aromatic compounds such as 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,5-dimethylstyrene, and 2,4,6-trimethylstyrene; ring-alkoxylated vinyl aromatic compounds such as 4-methoxystyrene and 4-ethoxystyrene; ring-halogenated vinyl aromatic compounds such as 2-chlorostyrene and 3-chlorostyrene; ring-ester-substituted vinyl aromatic compounds such as 4-acetoxystyrene; and ring-hydroxylated vinyl aromatic compounds such as 4-hydroxystyrene. vinyl esters such as vinyl benzoate and vinyl cyclohexanoate; vinyl halides such as vinyl chloride; aromatic monomers such as acenaphthalene and indene; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate and isopropyl methacrylate; aromatic methacrylates such as phenyl methacrylate; methacrylates such as isobornyl methacrylate and trimethylsilyl methacrylate; methacrylic monomers including methacrylic acid derivatives such as methacrylonitrile; certain acrylic acid esters such as isobornyl acrylate and tert-butyl acrylate; acrylic monomers including acrylic acid derivatives such as acrylonitrile, and the like. Further, examples of monomers that can be included in the monomer group a include acrylamide, isopropylacrylamide, N-vinylpyrrolidone, isobornyl methacrylate, dicyclopentanyl methacrylate, 2-methyl-2-adamantyl methacrylate, 1-adamantyl acrylate, and 1-adamantyl methacrylate, which, when made into a homopolymer, can provide a homopolymer having a Tg of 120° C. or higher. These monomers a may be used alone or in combination of two or more.

[0100] Examples of the monomer b include ethyl acrylate, butyl acrylate (also known as butyl acrylate), 2-ethylhexyl acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, 2-hydroxyethyl acrylate, and 4-hydroxybutyl acrylate. These monomers b may be used alone or in combination of two or more. Among these monomers b, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate are particularly preferred.

[0101] (Volume average particle size of elastic body) The volume average particle size of the elastomer is preferably 0.03 μm to 50.00 μm, more preferably 0.05 μm to 10.00 μm, more preferably 0.08 μm to 2.00 μm, even more preferably 0.10 μm to 1.00 μm, even more preferably 0.10 μm to 0.80 μm, and particularly preferably 0.10 μm to 0.50 μm. When the volume average particle size of the elastomer is (i) 0.03 μm or more, an elastomer having the desired volume average particle size can be stably obtained, and (ii) when it is 50.00 μm or less, the heat resistance and impact resistance of the resulting molded or cured product are excellent. The volume average particle size of the elastomer can be measured using a dynamic light scattering particle size distribution analyzer or the like, using an aqueous latex containing the elastomer as a sample. The method for measuring the volume average particle size of the elastomer is described in detail in the Examples below.

[0102] (elastic body ratio) The proportion of the elastomer in the polymer microparticles is preferably 40 to 97% by weight, more preferably 60 to 95% by weight, and even more preferably 70 to 93% by weight, based on 100% by weight of the entire polymer microparticles. When the proportion of the elastomer is (i) 40% by weight or more, the resulting resin composition can provide a molded article or cured product with excellent toughness and impact resistance, and (ii) when the proportion is 97% by weight or less, the polymer microparticles do not easily aggregate, preventing the resin composition from becoming highly viscous, and as a result, the resulting resin composition can be easy to handle.

[0103] (Modification of elastic body) In one embodiment of the present invention, the "elastic body" of the polymer microparticles may consist of only one type of elastomer having the same composition of structural units. In this case, the "elastic body" of the polymer microparticles is one type selected from the group consisting of diene rubbers, (meth)acrylate rubbers, and organosiloxane rubbers.

[0104] In one embodiment of the present invention, the "elastic body" of the polymer microparticles may be composed of multiple types of elastomers each having a different constitutional unit composition. In this case, the "elastic body" of the polymer microparticles may be two or more types selected from the group consisting of diene rubber, (meth)acrylate rubber, and organosiloxane rubber. In addition, in this case, the "elastic body" of the polymer microparticles may be one type selected from the group consisting of diene rubber, (meth)acrylate rubber, and organosiloxane rubber. In other words, the "elastic body" of the polymer microparticles may be multiple types of diene rubber, (meth)acrylate rubber, or organosiloxane rubber each having a different constitutional unit composition.

[0105] In one embodiment of the present invention, the case where the "elastic body" of the polymer microparticles is composed of multiple types of elastomers each having a different composition of constituent units will be described. In this case, each of the multiple types of elastomers will be referred to as elastomer 1, elastomer 2, ..., and elastomer 3. n Here, n is an integer of 2 or more. The "elastic bodies" of polymer microparticles are composed of separately polymerized elastomers 1, 2, ..., and n The "elastic body" of the polymer microparticles may include elastomer 1, elastomer 2, ..., and elastomer n may include a single elastomer obtained by sequentially polymerizing each of the above. Such sequential polymerization of multiple elastomers (polymers) is also called multistage polymerization. A single elastomer obtained by multistage polymerization of multiple types of elastomers is also called a multistage polymerized elastomer. The method for producing a multistage polymerized elastomer will be described in detail later.

[0106] Elastic body 1, Elastic body 2, ..., and Elastic body nIn the multi-stage polymerized elastomer, the elastomer n is an elastic body n-1 or an elastic body n-1 In the multi-stage polymerized elastomer, n Part of the material is elastic n-1 Sometimes it penetrates inside the

[0107] In a multistage polymerized elastomer, each of the multiple elastomers may form a layer structure. For example, when a multistage polymerized elastomer is composed of elastomer 1, elastomer 2, and elastomer 3, one embodiment of the present invention is one in which elastomer 1 forms the innermost layer, a layer of elastomer 2 is formed outside elastomer 1, and a layer of elastomer 3 is formed outside the layer of elastomer 2 as the outermost layer of the elastomer. In this way, a multistage polymerized elastomer in which each of the multiple elastomers forms a layer structure can also be called a multilayer elastomer. That is, in one embodiment of the present invention, the "elastomer" of the polymer microparticles may include (i) a composite of multiple types of elastomers, (ii) a multistage polymerized elastomer, and / or (iii) a multilayer elastomer.

[0108] (Surface crosslinked polymer) The rubber-containing graft copolymer preferably further comprises a surface-crosslinked polymer in addition to the elastomer and the graft moiety grafted to the elastomer. In other words, the polymer microparticle preferably further comprises a surface-crosslinked polymer in addition to the elastomer and the graft moiety grafted to the elastomer. Hereinafter, one embodiment of the present invention will be described using an example in which the polymer microparticles (e.g., rubber-containing graft copolymer) further comprise a surface-crosslinked polymer. In this case, (i) the blocking resistance can be improved in the production of polymer microparticles, and (ii) the dispersibility of the polymer microparticles in thermosetting resins is improved. The reasons for this are not particularly limited, but are presumed to be as follows: By coating at least a portion of the elastomer with the surface-crosslinked polymer, the exposed elastomer portion of the polymer microparticles is reduced, resulting in less adhesion between the elastomers, thereby improving the dispersibility of the polymer microparticles.

[0109] When the polymer microparticles contain a surface-crosslinked polymer, they can also have the following effects: (i) reducing the viscosity of the resin composition, (ii) increasing the crosslink density in the elastomer, and (iii) increasing the graft efficiency of the grafted portion. The crosslink density in the elastomer refers to the number of crosslinked structures in the entire elastomer.

[0110] The surface cross-linked polymer is composed of a polymer containing, as structural units, 30 to 100% by weight of structural units derived from polyfunctional monomers and 0 to 70% by weight of structural units derived from other vinyl monomers, totaling 100% by weight.

[0111] Examples of polyfunctional monomers that can be used in the polymerization of surface-crosslinked polymers include the same monomers as the polyfunctional monomers described above. Among these polyfunctional monomers, polyfunctional monomers that can be preferably used in the polymerization of surface-crosslinked polymers include allyl methacrylate, ethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate (e.g., 1,3-butylene glycol dimethacrylate), butanediol di(meth)acrylate, hexanediol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate, and polyethylene glycol di(meth)acrylates. These polyfunctional monomers may be used alone or in combination of two or more.

[0112] The polymer microparticles may contain a surface-crosslinked polymer polymerized independently of the polymerization of the rubber-containing graft copolymer, or may contain a surface-crosslinked polymer polymerized together with the rubber-containing graft copolymer. The polymer microparticles may also be a multistage polymer obtained by multistage polymerization of an elastomer, a surface-crosslinked polymer, and a graft moiety in this order. In either of these embodiments, the surface-crosslinked polymer can coat at least a portion of the elastomer.

[0113] The surface-crosslinked polymer can also be considered as a part of the elastomer. In other words, the surface-crosslinked polymer can also be considered as a part of the rubber-containing graft copolymer, and can also be called a surface-crosslinked polymerization part. When the polymer microparticles contain a surface-crosslinked polymer, the graft part may be (i) graft-bonded to an elastomer other than the surface-crosslinked polymer, (ii) graft-bonded to a surface-crosslinked polymer, or (iii) graft-bonded to both an elastomer other than the surface-crosslinked polymer and the surface-crosslinked polymer. When the polymer microparticles contain a surface-crosslinked polymer, the volume-average particle diameter of the elastomer mentioned above refers to the volume-average particle diameter of the elastomer containing the surface-crosslinked polymer.

[0114] The following describes a case (Case D) in which the polymer microparticles are multistage polymers obtained by multistage polymerization of an elastomer, a surface-crosslinked polymer, and a graft moiety in this order. In Case D, the surface-crosslinked polymer may cover a portion of the elastomer, or may cover the entire elastomer. In Case D, a portion of the surface-crosslinked polymer may penetrate into the interior of the elastomer. In Case D, the graft moiety may cover a portion of the surface-crosslinked polymer, or may cover the entire surface-crosslinked polymer. In Case D, a portion of the graft moiety may penetrate into the interior of the surface-crosslinked polymer. In Case D, the elastomer, the surface-crosslinked polymer, and the graft moiety may have a layer structure. For example, one embodiment of the present invention is one in which the elastomer is the innermost layer (core layer), a layer of surface-crosslinked polymer exists outside the elastomer as an intermediate layer, and a layer of graft moiety exists outside the surface-crosslinked polymer as an outermost layer (shell layer).

[0115] (Volume average particle size (Mv) of polymer microparticles) The volume average particle diameter (Mv) of the polymer microparticles is preferably 0.03 μm to 50.00 μm, more preferably 0.05 μm to 10.00 μm, more preferably 0.08 μm to 2.00 μm, even more preferably 0.10 μm to 1.00 μm, even more preferably 0.10 μm to 0.80 μm, and particularly preferably 0.10 μm to 0.50 μm, because this allows for the production of a resin composition having the desired viscosity and high stability. Having a volume average particle diameter (Mv) of the polymer microparticles within the above range also offers the advantage of improving the dispersibility of the polymer microparticles in the matrix resin. In this specification, the term "volume average particle diameter (Mv) of the polymer microparticles" refers to the volume average particle diameter of the primary particles of the polymer microparticles, unless otherwise specified. The volume average particle diameter of the polymer microparticles can be measured using a dynamic light scattering particle size distribution analyzer or the like, using an aqueous latex containing the polymer microparticles as a sample.

[0116] (Glass transition temperature of polymer particles) The glass transition temperature (Tg) of the polymer microparticles can be determined by the composition of the structural units contained in the polymer microparticles (e.g., the composition of the structural units contained in each of the elastomer and the graft portion). In other words, the Tg of the resulting polymer microparticles can be adjusted by changing the composition of the monomers used to produce (polymerize) the polymer microparticles (e.g., the composition of the monomers used to produce (polymerize) each of the elastomer and the graft portion).

[0117] The glass transition temperature (Tg) of the polymer microparticles can be calculated by the above-mentioned FOX formula (Formula 1), except that "graft portion of polymer microparticles" is replaced with "polymer microparticles".

[0118] (2-3. Method for producing polymer microparticles) An example of a method for producing polymer microparticles will be described below, taking as an example a case where the polymer microparticles contain a rubber-containing graft copolymer having an elastomer and a graft moiety grafted to the elastomer. The polymer microparticles can be produced, for example, by polymerizing the elastomer and then graft polymerizing a polymer that constitutes the graft moiety to the elastomer in the presence of the elastomer.

[0119] Polymer microparticles can be produced by known methods, such as emulsion polymerization, suspension polymerization, and microsuspension polymerization. Specifically, the polymerization of the elastomer, the polymerization of the graft moiety (graft polymerization), and the polymerization of the surface-crosslinked polymer in the polymer microparticles can be carried out by known methods, such as emulsion polymerization, suspension polymerization, and microsuspension polymerization. Among these, emulsion polymerization is particularly preferred as a method for producing polymer microparticles. Herein, the latex obtained by such emulsion polymerization may be referred to as "emulsion-polymerized latex." Emulsion polymerization has the following advantages: (i) the composition of the polymer microparticles can be easily designed; (ii) industrial production of polymer microparticles is easy; and (iii) latex suitable for use in the method for producing the present aggregates can be easily obtained. For these reasons, the latex used in the method for producing the present aggregates is preferably emulsion-polymerized latex. Below, we will explain the methods for producing the elastomer, graft moiety, and surface-crosslinked polymers of any configuration that may be contained in the polymer microparticles.

[0120] (Method of manufacturing elastic body) Consider a case where the elastomer contains at least one selected from the group consisting of diene rubbers and (meth)acrylate rubbers. In this case, the elastomer can be produced by a method such as emulsion polymerization, suspension polymerization, or microsuspension polymerization, and the production method can be, for example, the method described in WO2005 / 028546.

[0121] Consider a case where the elastomer contains an organosiloxane rubber. In this case, the elastomer can be produced by a method such as emulsion polymerization, suspension polymerization, or microsuspension polymerization, and the production method can be, for example, the method described in WO2006 / 070664.

[0122] The "elastic body" of polymer particles is made up of multiple types of elastic bodies (e.g., elastic body 1, elastic body 2, ..., elastic body n ) will be explained. In this case, elastic body 1, elastic body 2, ..., elastic body n Alternatively, the elastomers may be polymerized separately by the above-mentioned method, and then mixed and compounded to produce a composite consisting of multiple types of elastomers. n may be sequentially polymerized in multiple stages to produce one elastomer composed of multiple types of elastomers.

[0123] The multi-stage polymerization of elastomers will now be specifically described. For example, a multi-stage polymerized elastomer can be obtained by carrying out the following steps (1) to (4) in order: (1) polymerizing elastomer 1 to obtain elastomer 1; (2) subsequently polymerizing elastomer 2 in the presence of elastomer 1 to obtain a two-stage elastomer. 1+2 (3) Then, the elastic body 1+2 In the presence of 1+2+3 (4) After the same procedure, the elastic body 1+2+···+(n-1) In the presence of elastic n Multi-stage polymerized elastomer 1+2+···+n get.

[0124] (Method for manufacturing the graft portion) The graft portion can be formed, for example, by polymerizing the monomer used to form the graft portion by known radical polymerization in the presence of any polymer (e.g., an elastomer). When (i) the elastomer or (ii) the polymer microparticle precursor containing the elastomer and the surface-crosslinked polymer is obtained as an aqueous latex, the polymerization of the graft portion is preferably carried out by emulsion polymerization. The graft portion can be produced, for example, according to the method described in WO2005 / 028546.

[0125] The graft portion is a plurality of types of graft portions (e.g., graft portion 1, graft portion 2, ..., graft portion n In this case, the graft portion 1, the graft portion 2, ..., the graft portion n may be polymerized separately by the above-mentioned method, and then mixed and composited to produce a graft portion (composite) consisting of multiple types of graft portions. Alternatively, graft portion 1, graft portion 2, ..., graft portion n may be sequentially polymerized in multiple stages to produce one graft moiety consisting of multiple types of graft moieties.

[0126] The multi-stage polymerization of the graft portion will be specifically described. For example, a multi-stage polymerization graft portion can be obtained by sequentially carrying out the following steps (1) to (4): (1) polymerizing graft portion 1 to obtain graft portion 1; (2) subsequently polymerizing graft portion 2 in the presence of graft portion 1 to obtain a two-stage graft portion. 1+2 (3) Then, the graft portion is obtained. 1+2 The graft portion 3 is polymerized in the presence of 1+2+3 (4) After the same procedure, the grafted part is obtained. 1+2+···+(n-1) In the presence of n is polymerized to form a multi-stage grafted portion. 1+2+···+n get.

[0127] When the graft moiety is composed of a plurality of types of graft moieties, the graft moieties having the plurality of types of graft moieties may be polymerized, and then the graft moieties may be graft polymerized onto an elastomer to produce polymer microparticles. Alternatively, the plurality of types of polymers constituting the graft moieties may be graft polymerized in order onto the elastomer in the presence of the elastomer to produce polymer microparticles.

[0128] (Method of producing surface cross-linked polymer) The surface cross-linked polymer can be formed by polymerizing a monomer used for forming the surface cross-linked polymer in the presence of an arbitrary polymer (e.g., an elastomer) by known radical polymerization. When the elastomer is obtained as an aqueous latex, the polymerization of the surface cross-linked polymer is preferably carried out by emulsion polymerization.

[0129] When emulsion polymerization is employed as a method for producing polymer microparticles, a known emulsifier (dispersant) can be used as the emulsifier (dispersant) for producing the polymer microparticles.

[0130] Examples of emulsifiers include anionic emulsifiers, nonionic emulsifiers, polyvinyl alcohol, alkyl-substituted cellulose, polyvinylpyrrolidone, and polyacrylic acid derivatives. Examples of anionic emulsifiers include sulfur-based emulsifiers, phosphorus-based emulsifiers, sarcosinic acid-based emulsifiers, and carboxylic acid-based emulsifiers. Examples of sulfur-based emulsifiers include sodium dodecylbenzenesulfonate (abbreviation: SDBS). Examples of phosphorus-based emulsifiers include sodium polyoxyethylene lauryl ether phosphate.

[0131] When a polyfunctional monomer is used in the polymerization of the elastomer, graft portion, or surface-crosslinked polymer for the purpose of introducing a crosslinked structure into the elastomer, graft portion, or surface-crosslinked polymer, a known chain transfer agent can be used in a known amount range. By using the chain transfer agent, the molecular weight and / or degree of crosslinking of the resulting elastomer, graft portion, or surface-crosslinked polymer can be easily adjusted.

[0132] In addition to the above-mentioned components, a surfactant may be used in the production of polymer microparticles. The type and amount of the surfactant used are within known ranges.

[0133] In the production of polymer microparticles, conditions within known numerical ranges can be appropriately applied to the polymerization conditions such as polymerization temperature, pressure, and deoxidation.

[0134] A latex containing polymer microparticles can be obtained by the above-mentioned method for producing polymer microparticles. That is, the description in the section (2-3. Method for producing polymer microparticles) can be used as a description for producing a latex.

[0135] (2-4. Thickener) The latex may further contain a thickener. The inclusion of a thickener in the latex facilitates the formation of a soft agglomerated state of the latex. The formation of a soft agglomerated state of the latex has the advantage of further increasing the bulk density of the powder or granule produced from the agglomerates obtained by the present agglomerate production method, and further enhancing the effect of reducing the amount of fine powder used during the production of the powder or granule. In this specification, the "soft agglomerated state" of the latex refers to a state in which the viscosity of the latex is increased compared to before the addition of the thickener due to crosslinking between polymer microparticles contained in the latex by the thickener.

[0136] Known thickeners can be used as the thickener. Examples of thickeners suitable for use in the present method for producing an aggregate include water-soluble polymers. Examples of water-soluble polymers include nonionic water-soluble polymers, anionic water-soluble polymers, cationic water-soluble polymers, and amphoteric water-soluble polymers. Among these, nonionic water-soluble polymers are more preferred.

[0137] Examples of nonionic water-soluble polymers include polyalkylene oxides (e.g., polyethylene oxide, polypropylene oxide, etc.), polyvinyl alcohol, methyl cellulose, hydroxyethyl methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, sodium polyacrylate, polyvinyl pyrrolidone, polyacrylamide, polydimethylaminoethyl methacrylate, etc. Among these, polyethylene oxide and methyl cellulose are particularly preferred.

[0138] Polyethylene oxide includes polymers having ethylene oxide units obtained by polymerizing ethylene oxide, such as ethylene oxide homopolymers, higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, ethylene oxide adducts of fats and oils, and polypropylene glycol ethylene oxide adducts.

[0139] The molecular weight of the thickener (e.g., polyethylene oxide) is not particularly limited, but the viscosity-average molecular weight is preferably 600,000 to 8,000,000, and more preferably 1,500,000 to 5,000,000. This configuration has the advantage that the latex is more likely to form a soft aggregate state and that a sudden increase in viscosity of the latex due to the addition of the thickener can be prevented. The viscosity-average molecular weight M of polyethylene oxide can be calculated from the intrinsic viscosity η of polyethylene oxide using the following formula (Equation 2) (see J. Appl. Polymer Sci., 1, 56 (1959)). η = 6.4 × 10 -6 ×M 0.82 (Staudinger formula) (Equation 2). The intrinsic viscosity η of polyethylene oxide is a value obtained by measurement in pure water at a measurement temperature of 35°C using a capillary viscometer.

[0140] The thickener can be added to the latex in the form of an aqueous solution or in the form of a solid (e.g., powder). It is preferable to add the thickener to the latex in the form of an aqueous solution, since this simplifies the process. There is no particular limitation on the method of adding the thickener to the latex. A predetermined amount of the thickener may be added to the latex (a) all at once, (b) dividedly in several portions, or (c) continuously.

[0141] The case where a thickener is added to latex in the form of an aqueous solution will be described below. The concentration of the thickener in the aqueous solution is not particularly limited, but from the viewpoints of (a) providing the aqueous solution with a viscosity suitable for handling and (b) preventing the water content of the latex from becoming too high, the concentration is preferably 0.01% to 10.00% (weight / weight), for example, and more preferably 0.10% to 10.00% (weight / weight).

[0142] The content of the thickener in the latex (based on the solid content) is preferably 0.010 to 3,000 parts by weight (100 ppm to 30,000 ppm) and more preferably 0.015 to 0.050 parts by weight (150 to 500 ppm) relative to 100 parts by weight of the polymer fine particles in the latex. This configuration has the following advantages: (a) the viscosity of the latex increases within an appropriate range, (b) a soft flocculation state is quickly formed, (c) the time during which the latex containing the polymer fine particles is in contact with the coagulant in the device (in other words, the time of the coagulation process) can be shortened, thereby reducing production costs, and (d) the amount of fine powder during the production of powder or granules is further reduced.

[0143] (2-5. Coagulant solution) The coagulant solution used in the present method for producing an aggregate refers to a solution containing a liquid coagulant and a solvent and a coagulant. In this specification, the coagulant solution used in one embodiment of the present invention may be referred to as the "present coagulant solution." In the present coagulant solution, the coagulant may be dispersed or dissolved in the solvent.

[0144] As used herein, a liquid coagulant refers to a liquid substance that functions as a coagulant (i.e., a substance whose solute itself is liquid without being dissolved or dispersed in a solvent). When a liquid substance is used as a coagulant, the substance (coagulant) can be used as a coagulant solution without being dissolved or dispersed in a solvent. In other words, the "coagulant solution" in this method for producing an aggregate also encompasses the liquid substance itself that functions as a coagulant.

[0145] When a solution containing a solvent and a coagulant is used as the coagulant solution, the solvent for the coagulant solution is not particularly limited, but may be, for example, water.

[0146] The coagulant contained in the coagulant solution may be any substance capable of coagulating and solidifying the polymer particles in the latex. Examples of coagulants include (i) inorganic acids (salts) and / or organic acids (salts), and (ii) polymeric coagulants. These coagulants may be used singly or in combination of two or more. In this specification, inorganic acids (salts) refer to "inorganic acids and their salts," and organic acids (salts) refer to "organic acids and their salts."

[0147] The coagulant solution is preferably an aqueous solution containing, as a coagulant, one or more substances selected from the group consisting of monovalent inorganic acids, salts of monovalent inorganic acids, divalent inorganic acids, salts of divalent inorganic acids, trivalent inorganic acids, salts of trivalent inorganic acids, etc. Examples of monovalent inorganic acids include (a) halogen acids such as chloric acid, bromic acid, and iodic acid, and (b) nitric acid, etc. Examples of divalent inorganic acids include sulfuric acid, etc. Examples of trivalent inorganic acids include phosphoric acid, etc. Examples of cationic elements or molecules that can form salts with these inorganic acids include alkali metals, alkaline earth metals, transition metals (especially iron and zinc), Group 13 metals such as aluminum, and ammonium, etc.

[0148] The coagulant solution preferably contains, as a coagulant, one or more substances selected from the group consisting of monovalent organic acids, monovalent organic acid salts, divalent organic acids, divalent organic acid salts, etc. Examples of monovalent organic acids include formic acid and acetic acid. Examples of monovalent organic acid salts include salts of formic acid, acetic acid, etc. with alkali metals, etc. Examples of divalent organic acids include oxalic acid, malic acid, maleic acid, malonic acid, tartaric acid, etc. Examples of divalent organic acid salts include salts of acetic acid, formic acid, etc. with alkaline earth metals, etc.

[0149] (i) Specific examples of inorganic acids (salts) and / or organic acids (salts) include: (a) Alkali metal halides such as sodium chloride, potassium chloride, lithium chloride, sodium bromide, potassium bromide, lithium bromide, potassium iodide, and sodium iodide; alkali metal sulfides such as potassium sulfate and sodium sulfate; ammonium sulfate; ammonium chloride; alkali metal nitrates such as sodium nitrate and potassium nitrate; inorganic salts such as calcium chloride, ferrous sulfate, magnesium sulfate, zinc sulfate, copper sulfate, barium chloride, ferrous chloride, ferric chloride, magnesium chloride, ferric sulfate, aluminum sulfate, potassium alum, and iron alum; (b) inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; (c) organic acids such as acetic acid, formic acid, and the like; and (d) Organic acid salts such as sodium acetate, calcium acetate, sodium formate, calcium formate, and salts of these organic acids;

[0150] The polymer coagulant is not particularly limited as long as it is a polymer compound having a hydrophilic group and a hydrophobic group. Examples of the polymer coagulant include anionic polymer coagulants, cationic polymer coagulants, and nonionic polymer coagulants. Among these, cationic polymer coagulants are preferred because they have the advantage of neutralizing the charge of the polymer microparticles.

[0151] Cationic polymer coagulants include polymer coagulants that have cationic groups in the molecule, i.e., polymer coagulants that exhibit cationic properties when dissolved in water.Specific examples of cationic polymer coagulants include polyamines, polydicyandiamides, cationized starch, cationic poly(meth)acrylamide, water-soluble aniline resins, polythiourea, polyethyleneimine, quaternary ammonium salts, polyvinylpyridines, chitosan, etc.

[0152] Among the above-mentioned coagulants, (a) an aqueous solution of a monovalent or divalent inorganic acid salt such as sodium chloride, potassium chloride, sodium sulfate, ammonium chloride, calcium chloride, magnesium chloride, magnesium sulfate, or barium chloride, or (b) an aqueous solution of a monovalent or divalent inorganic acid such as hydrochloric acid or sulfuric acid can be preferably used, since these can further enhance the effect of one embodiment of the present invention.

[0153] This coagulant solution can be obtained, for example, by mixing a solid (e.g., powder) substance that functions as a coagulant with a solvent. When mixing multiple types of coagulants, each coagulant may be (a) mixed with a solvent all at once, or (b) mixed individually. Also, commercially available coagulants that are pre-dissolved or pre-dispersed in a solvent may be (a) used as a coagulant solution as is, or (b) further mixed with a solvent before use.

[0154] Furthermore, in the present method for producing an aggregate, a liquid substance that functions as a coagulant (i.e., a substance whose solute is itself liquid without being dissolved or dispersed in a solvent) may be used as the coagulant. When a liquid substance is used as the coagulant, the substance (coagulant) may be used after being dissolved or dispersed in a solvent to form a solution, or the substance (coagulant) may be used by spraying it directly without being dissolved or dispersed in a solvent.

[0155] The concentration of the coagulant in the coagulant solution is not particularly limited, but is preferably 0.1 wt% to 45.0 wt%, more preferably 5.0 wt% to 40.0 wt%, and even more preferably 10.0 wt% to 35.0 wt% based on the total weight of the coagulant solution (100 wt%). This configuration facilitates the coagulation action of the coagulant, allowing for a reduction in the amount of coagulant used. As a result, this method offers the advantages of (a) reducing the production costs of the aggregates and granules, and (b) reducing the amount of coagulant-derived impurities contained in the aggregates and granules.

[0156] When the coagulant is a solid (e.g., powder) substance, the concentration of the coagulant in the coagulant solution can be calculated, for example, by the following method: 0.5 g of the coagulant solution is placed in a hot-air convection dryer at a temperature higher than the boiling point of the solvent (e.g., 20°C above the boiling point of the solvent) for 3 hours to evaporate the solvent. The weight (g) of the residue (solids) after drying is then measured. The resulting value is then divided by the weight (0.5 g) of the coagulant solution before drying, and the resulting value is then multiplied by 100. The residue after drying, i.e., the solids, primarily contains the coagulant. Therefore, the "concentration of the coagulant in the coagulant solution" calculated by the above method can also be rephrased as the "concentration of the solids in the coagulant solution." Furthermore, when the coagulant is liquid, the concentration of the coagulant in the coagulant solution can also be measured by fractional distillation.

[0157] (2-6.Device) The apparatus used in this aggregate production method (hereinafter sometimes referred to as the production apparatus or the apparatus) is not particularly limited as long as it includes a vessel (sometimes referred to as a "coagulation tank") in which a gaseous region is formed where droplets of sprayed and / or dripped polymer microparticle latex and droplets of sprayed coagulant solution can come into contact; a nozzle communicating with the interior of the apparatus as a latex introduction section capable of vertically spraying and / or dripping the latex; and a two-fluid and / or one-fluid nozzle communicating with the interior of the apparatus as a coagulant solution introduction section capable of horizontally spraying the coagulant solution, capable of setting an air flow rate of less than 60 L / min. Hereinafter, the nozzle used as the latex introduction section will also be referred to as the "first nozzle," and the nozzle used as the coagulant solution introduction section will also be referred to as the "second nozzle."

[0158] The apparatus may be, for example, an apparatus equipped with a vessel having a vertical or nearly vertical inner wall. The apparatus may be, for example, an apparatus equipped with a first nozzle at the top (column top) of the vessel and a second nozzle at the side (inner wall) of the vessel. The vessel may also have, at its bottom, a receiving tank equipped with an aqueous phase region for collecting aggregates generated in the gas phase region of the vessel.

[0159] The shape of the vessel is not particularly limited, but is preferably a cylindrical shape, a polygonal prism shape, etc., and more preferably a cylindrical shape. When the vessel is cylindrical, its diameter is preferably, for example, 30 cm to 500 cm. Furthermore, the height from the top of the vessel to the bottom (when the vessel has a receiving tank, the liquid level (aqueous phase level) of the receiving tank) is preferably 50 cm to 10 m, more preferably 1 m to 5 m, and even more preferably 2 m to 3 m, from the viewpoint of appropriately progressing aggregation of polymer fine particles in the latex in the gas phase.

[0160] The apparatus may also be connected, as necessary, to a recovery device for recovering the resulting agglomerates from the apparatus, a drying device for drying the recovered agglomerates to obtain powder or granules, and a temperature control device for adjusting the temperature inside the container, the temperature of the latex of the polymer microparticles and / or the temperature of the coagulant solution.

[0161] (2-7. Contact process) The method for producing the aggregates includes a contacting step of spraying and / or dropping the latex vertically and spraying the coagulant solution horizontally to bring the droplets of the latex and the droplets of the coagulant solution into contact with each other. The contact between the droplets of the latex and the droplets of the coagulant solution can produce aggregates of polymer fine particles.

[0162] In the contacting step, droplets of latex and droplets of coagulant solution are brought into contact with each other in a gas phase, thereby forming aggregates of polymer fine particles in the droplets containing the latex and the coagulant solution. The droplets containing the latex and the coagulant solution obtained in the contacting step can also be said to be "droplets in which the latex and the coagulant solution are integrated" or "droplets of a solution containing polymer fine particles derived from the latex and a coagulant derived from the coagulant solution."

[0163] In the contact step, the order of spraying and / or dropping the latex of polymer microparticles and spraying the coagulant solution is not particularly limited, and they may be performed simultaneously, or the spraying of the coagulant solution may be performed before the spraying and / or dropping of the latex of polymer microparticles. For example, the coagulant solution may be sprayed in advance, and then the latex of polymer microparticles may be sprayed and / or dropped into the region containing the coagulant solution in an aerosol form, so that the latex droplets and the coagulant solution droplets are brought into contact with each other.

[0164] In the contacting step, a two-fluid nozzle with an air flow rate set to less than 60 L / min is used as the second nozzle for spraying the coagulant solution, and / or a one-fluid nozzle is used for spraying the coagulant solution.

[0165] By using a two-fluid nozzle with an air flow rate set to less than 60 L / min and / or a single-fluid nozzle as the second nozzle, it is possible to reduce turbulence in the air flow inside the coagulation tank, which can occur when the coagulant solution is sprayed horizontally together with the gas. This reduces the amount of agglomerates of polymer microparticles adhering to the inner wall surface of the coagulation tank, improving the recovery rate of the agglomerates and enabling the production of agglomerates with high circularity and granular products with high circularity and high bulk density.

[0166] When a two-fluid nozzle is used as the second nozzle, a gas such as air, nitrogen, or carbon dioxide can be sprayed simultaneously with the coagulant solution, allowing the coagulant solution to be contained in the gas phase in the form of an aerosol with smaller droplet diameters. The air flow rate of the two-fluid nozzle used to spray the coagulant solution may be set to less than 60 L / min, but is preferably 50 L / min or less, even more preferably 40 L / min or less, even more preferably 30 L / min or less, even more preferably 20 L / min or less, and even more preferably 10 L / min or less. Alternatively, the air flow rate may be set to zero by stopping the gas supply and spraying only the coagulant solution.

[0167] When a one-fluid nozzle is used as the second nozzle, it is possible to spray only the coagulant solution without mixing it with a gas.

[0168] In particular, the second nozzle is preferably a single-fluid nozzle, since this avoids the need for complicated piping and equipment and reduces running costs. In other words, it is more preferable to use a single-fluid nozzle for spraying the coagulant solution in the contact step.

[0169] The diameter of the second nozzle is, for example, 0.01 mm to 2.00 mm, more preferably 0.05 mm to 1.50 mm, and even more preferably 0.10 mm to 1.00 mm. When the diameter is 2.00 mm or less, there is no risk of the sprayed droplets of coagulant solution becoming excessively large, and polymer fine particles can be sufficiently aggregated in droplets containing latex and coagulant solution. This has the advantage of being able to obtain aggregates that can provide powders with a high bulk density. Furthermore, when the diameter of the second nozzle is 0.01 mm or more, the possibility of the nozzle clogging during spraying of the coagulant solution can be reduced, allowing for stable production of aggregates.

[0170] The spray pressure of the second nozzle is, for example, 0.5 kg / cm 2 ~100.0kg / cm 2 and more preferably 1.0 kg / cm 2 ~5.0kg / cm 2 The spray pressure of the second nozzle is 0.5 kg / cm 2 If the spray pressure of the second nozzle is 100.0 kg / cm or more, there is no risk that the droplets of the sprayed coagulant solution will become excessively large, and the droplet density of the coagulant solution in the gas phase will increase, which has the advantage of increasing the coagulant capture efficiency, in other words, the advantage of being able to efficiently contact the latex droplets with the coagulant droplets. 2 If the temperature is below this range, there is no risk that the scattering range of the droplets will be too wide and the droplet density in the gas phase will be low, and therefore there is an advantage that the latex droplets can be efficiently contacted with the coagulant solution.

[0171] The first nozzle is not particularly limited as long as it can spray and / or drip the latex, and a pressure nozzle, two-fluid nozzle, ultrasonic nozzle, high-frequency device, drip nozzle, or the like can be appropriately selected and used. Among them, a pressure nozzle is more preferable as the first nozzle, and a swirl flow nozzle is even more preferable because it can easily spray droplets having a volume average droplet diameter of 200 μm to 400 μm and a sharp particle size distribution, and is economically superior among nozzles capable of spraying such droplets. When the latex is sprayed and / or dripped from the first nozzle, the latex droplets and the coagulant solution droplets can be combined in the gas phase, and polymer microparticles can be aggregated in the droplets containing the latex and the coagulant solution.

[0172] The diameter of the first nozzle is, for example, 0.01 mm to 2.00 mm, preferably 0.05 mm to 1.50 mm, and more preferably 0.10 mm to 1.00 mm. When the diameter is 2.00 mm or less, there is no risk that the sprayed and / or dripped droplets of latex will become excessively large, and polymer fine particles can be sufficiently aggregated in droplets containing latex and coagulant solution. This has the advantage of being able to obtain aggregates that can provide powder or granules with a high bulk density. On the other hand, when the diameter of the first nozzle is 0.01 mm or more, the possibility of the first nozzle hole being clogged during spraying and / or dripping of latex can be reduced, allowing for stable production of aggregates.

[0173] The spray pressure of the first nozzle is, for example, 0.5 kg / cm 2 ~30.0kg / cm 2 , preferably 1.0 kg / cm 2 ~10.0kg / cm 2 The spray pressure of the first nozzle is 0.5 kg / cm 2 If the spray pressure of the first nozzle is 30.0 kg / cm or more, there is no risk that the droplets of the sprayed latex will become excessively large, and as a result, there is an advantage that the aggregation reaction of the polymer fine particles in the gas phase is suitably completed. 2If the particle size is less than this, there is no risk that the droplets of the sprayed latex will become excessively small, and as a result, there is an advantage in that the amount of fine powder in the powder or granule produced from the obtained agglomerates is reduced.

[0174] The first nozzle is preferably installed at the top of the vessel (tower top). Furthermore, the vertical distance between the first nozzle and the bottom of the vessel (or the liquid level (aqueous phase level) of the receiving vessel, if the production apparatus has the receiving vessel) is preferably 100 cm or more, more preferably 150 cm or more, and even more preferably 200 cm or more, because this allows for a sufficient solidification time and provides a powder or granular material with superior powder quality. The upper limit of the vertical distance between the first nozzle and the bottom of the vessel is preferably 300 cm or less, from the viewpoint of preventing the apparatus from becoming excessively large.

[0175] In this specification, the "vertical distance between the first nozzle and the bottom of the container (if the manufacturing apparatus has a receiving tank, the liquid level (aqueous phase level) of the receiving tank)" refers to the vertical distance between the center of the outlet of the first nozzle and the bottom of the container (if the manufacturing apparatus has a receiving tank, the liquid level (aqueous phase level) of the receiving tank). Note that if there are multiple first nozzles, the shortest (closest) value among the vertical distances between each first nozzle and the bottom of the container is taken as the vertical distance between the first nozzle and the bottom of the container.

[0176] The tip angle of the spray cone of the latex sprayed or dripped from the first nozzle is not particularly limited, but is preferably 5° to 140°, and more preferably 30° to 90°. When the angle of the spray cone of the latex is within this range, (i) aggregates can be produced efficiently, and (ii) the apparatus used to produce the aggregates can be prevented from becoming excessively large. Furthermore, (iii) by setting the tip angle of the spray cone to 5° or more, it is possible to prevent the sprayed or dripped latex droplets from coalescing and increasing the droplet size. Furthermore, (iv) by setting the tip angle of the spray cone to 90° or less, it is possible to reduce the amount of sprayed or dripped latex droplets that adhere to the wall surface of the apparatus used to produce the aggregates. Furthermore, since it is not necessary to increase the size of the apparatus to prevent the latex droplets from adhering to the wall surface, the apparatus can be made smaller. In this specification, the term "spray cone" refers to the aggregate of droplets of the liquid sprayed or dripped from the nozzle outlet, observed when the liquid is sprayed or dripped. The shape of the spray cone of the latex is not particularly limited, and may be, for example, a fan shape, an open cone shape, or a full cone shape.

[0177] The number of first nozzles is not particularly limited and may be one or more than one. When two or more first nozzles are used, (a) each nozzle may only spray latex, (b) each nozzle may only drip latex, or (c) at least one nozzle may spray latex while at least another nozzle drips latex.

[0178] The position of the second nozzle is not particularly limited as long as it is a position where the coagulant solution can be sprayed horizontally and the latex droplets and the coagulant solution droplets can come into contact with each other. The second nozzle is preferably provided on the side surface (inner wall) of the container so that the spray direction is horizontal, allowing the coagulant solution to be sprayed horizontally. Furthermore, the second nozzle is preferably provided below the first nozzle so that the latex droplets and the coagulant solution droplets can come into contact with each other.

[0179] The vertical distance between the first nozzle and the second nozzle is preferably 20 cm to 50 cm, more preferably 25 cm to 45 cm, and even more preferably 20 cm to 40 cm, because this allows for efficient contact between the droplets containing latex and the droplets of the coagulant solution. Furthermore, the vertical distance between the second nozzle and the bottom of the container (if the manufacturing apparatus has a receiving tank, the liquid level (aqueous phase level) of the receiving tank) is preferably 50 cm or more, more preferably 100 cm or more, and even more preferably 150 cm or more, because this allows for sufficient coagulation time and provides a powder or granular material with superior powder properties. The upper limit of the vertical distance between the second nozzle and the bottom of the container is preferably 250 cm or less, from the viewpoint of preventing the apparatus from becoming excessively large.

[0180] In this specification, the "vertical distance between the first nozzle and the second nozzle" is a value measured by the following method: (1) drawing a vertical line (first line) passing through the center of the outlet (hole) of the first nozzle; (2) drawing a horizontal line (perpendicular to the vertical direction) passing through the center of the outlet (hole) of the second nozzle (second line); (3) the vertical distance between the intersection of the first line and the second line and the center of the outlet of the first nozzle is defined as the "vertical distance between the first nozzle and the second nozzle." Note that when there are multiple nozzles to be compared for distance (for example, when there are multiple first nozzles and multiple second nozzles), the shortest (closest) value among the distances between different types of nozzles is defined as the distance between the nozzles. Furthermore, in this specification, the "vertical distance between the second nozzle and the bottom of the container (if the manufacturing apparatus has the receiving tank, the liquid level (aqueous phase level) of the receiving tank)" refers to the vertical distance between the center of the outlet of the second nozzle and the bottom of the container (if the manufacturing apparatus has the receiving tank, the liquid level (aqueous phase level) of the receiving tank). Note that if there are multiple second nozzles, the shortest (closest) value among the vertical distances between each second nozzle and the bottom of the container is taken as the vertical distance between the second nozzle and the bottom of the container.

[0181] The tip angle of the spray cone of the coagulant solution sprayed from the second nozzle is not particularly limited, but is preferably 5° to 140°, and more preferably 30° to 90°. When the angle of the spray cone of the coagulant solution is within the above range, (i) the latex droplets and the additive solution droplets can be efficiently brought into contact with each other, and (ii) the apparatus used to produce the aggregates can be prevented from becoming excessively large. Furthermore, (iii) in particular, by setting the tip angle of the spray cone to 5° or more, it is possible to prevent droplets of the sprayed coagulant solution from coalescing and increasing in droplet size, (iv) by setting the tip angle of the spray cone to 90° or less, it is possible to reduce the amount of droplets of the sprayed coagulant solution that adhere to the wall surfaces of the apparatus for producing aggregates, and since it is not necessary to increase the size of the apparatus to prevent droplets of the coagulant solution from adhering to the wall surfaces, it is possible to downsize the apparatus, and (v) there is no risk that the droplets of the coagulant solution will fly over an excessively wide range, thereby reducing the droplet density in the gas phase, so there is an advantage that the latex droplets and the coagulant solution can be efficiently contacted. In addition, the shape of the spray cone for the coagulant solution is not particularly limited, and it may be, for example, a fan shape, an open cone shape, or a filled cone shape.

[0182] The number of second nozzles is not particularly limited and may be one or two or more. Furthermore, when two or more nozzles are used as second nozzles, all of the second nozzles may be bi-fluid nozzles with an air flow rate set to less than 60 L / min, or all may be mono-fluid nozzles, or a combination of these may be used. Furthermore, when using multiple bi-fluid nozzles with an air flow rate set to less than 60 L / min, it is sufficient that each of the bi-fluid nozzles is a bi-fluid nozzle with an air flow rate set to less than 60 L / min.

[0183] The volume average droplet diameter of the latex droplets sprayed and / or dropped in the contacting step is preferably 50 μm to 5 mm, more preferably 100 μm to 800 μm, even more preferably 150 μm to 600 μm, and particularly preferably 200 μm to 400 μm. If the volume average droplet diameter of the latex droplets sprayed and / or dropped is 50 μm or more, the amount of fine powder in the powder or granule obtained by producing the resulting aggregates can be reduced. Furthermore, if the volume average droplet diameter of the latex droplets sprayed and / or dropped is 5 mm or less, the polymer fine particles in the latex droplets can be sufficiently aggregated, and the resulting aggregates can have a high bulk density and a low amount of fine powder.

[0184] The volume average droplet diameter of the droplets of the coagulant solution sprayed in the contact step is preferably 0.01 μm to 500.00 μm, more preferably 0.05 μm to 100.00 μm, and even more preferably 0.10 μm to 50.00 μm. According to the above configuration, it is possible to provide aggregates with further improved bulk density, circularity, and recovery rate.

[0185] The volume average droplet diameter of the droplets of the latex and the coagulant solution can be measured, for example, by a laser diffraction spray droplet diameter measuring device.

[0186] In the contacting step, the amount of coagulant sprayed can be appropriately adjusted depending on the type (composition) of polymer microparticles, the type of coagulant, the concentration of polymer microparticles (solid content) in the latex, and the concentration of coagulant (solid content) in the coagulant solution. In this specification, the "amount of coagulant sprayed" can also be referred to as the "amount of coagulant brought into contact with droplets of latex," and refers to the amount of coagulant (solid content) in the coagulant solution sprayed per unit time relative to the amount of polymer microparticles (solid content) in the latex sprayed and / or dropped per unit time. The "amount of coagulant sprayed" can also be referred to as the "amount of coagulant brought into contact with droplets of latex." Because of the advantages of (a) preventing the occurrence of unagglomerated polymer microparticles in droplets containing latex and coagulant solution, thereby producing more aggregates, and (b) reducing the amount of coagulant-derived impurities in the resulting aggregates and granules, the amount of coagulant sprayed is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and even more preferably 3 to 15 parts by weight, per 100 parts by weight of polymer microparticles in the latex sprayed and / or dropped per unit time (amount of polymer microparticles sprayed and / or dropped). The "amount of coagulant sprayed" can be adjusted by appropriately changing the concentration of the coagulant (solids) in the coagulant solution, the amount of coagulant solution sprayed per unit time, etc.

[0187] The temperature of the latex when subjected to the contacting step (immediately before spraying and / or dropping) is not particularly limited. In one embodiment of the present invention, the temperature of the latex when subjected to the contacting step is, for example, preferably 1°C to 100°C, more preferably 1°C or higher and lower than 100°C, more preferably 5°C to 80°C, even more preferably 10°C to 70°C, and particularly preferably 20°C to 50°C. When the temperature of the latex when subjected to the contacting step is within the above range, there is an advantage that the stability of the latex can be ensured.

[0188] The temperature of the coagulant solution when subjected to the contact step (immediately before spraying) is not particularly limited. In one embodiment of the present invention, the temperature of the coagulant solution when subjected to the contact step is, for example, preferably 1°C to 100°C, more preferably 1°C or higher and less than 100°C, more preferably 5°C to 80°C, even more preferably 10°C to 70°C, and particularly preferably 20°C to 50°C. When the temperature of the coagulant solution when subjected to the contact step is within the above range, there is an advantage that there is no risk of the coagulant precipitating and the stability of the coagulant solution can be ensured.

[0189] The temperature inside the vessel in the contacting step (the temperature of the region where the latex droplets and the coagulant solution droplets come into contact) is not particularly limited, but is, for example, preferably 1°C to 100°C, more preferably 1°C or higher and lower than 100°C, more preferably 5°C to 80°C, more preferably 10°C to 70°C, more preferably 15°C to 60°C, more preferably 15°C to 50°C, even more preferably 15°C to 45°C, and particularly preferably 15°C or higher and lower than 45°C. When the temperature inside the vessel in the contacting step is within the above range, the latex droplets and the coagulant solution droplets can come into efficient contact with each other, which has the advantage of allowing the polymer microparticles to be sufficiently aggregated in the liquid containing the latex and the coagulant solution.

[0190] In the present method for producing an aggregate, the contacting step may be performed while allowing water to flow down along the inner wall surface of a container in which the contacting step is performed (flowing-down operation). According to one embodiment of the present invention, the second nozzle is used to spray the coagulant solution, thereby reducing adhesion of the aggregates, the latex sprayed and / or dropped into the gas phase, and the coagulant solution sprayed into the gas phase to the inner wall surface of the container. Furthermore, if any adhesion exists on the inner wall surface, the adhesion can be removed. The amount of water flowing down along the inner wall surface is not particularly limited. According to one embodiment of the present invention, adhesion of the latex, the coagulant solution, and the obtained aggregates to the inner wall surface of the container is reduced, thereby reducing the amount of water used compared to conventional methods and alleviating the burden of wastewater treatment. The temperature of the water flowing down along the inner wall surface is preferably 0°C to 100°C, more preferably 10°C to 60°C, from the viewpoint of simplifying the flow-down operation.

[0191] 3. Method for producing powder and granular material A method for producing powder or granular material according to one embodiment of the present invention includes a recovery step of recovering the agglomerates obtained by the method for producing the agglomerates, and a drying step of drying the recovered agglomerates. In this specification, the method for producing powder or granular material according to one embodiment of the present invention may be referred to as "the method for producing the powder or granular material according to the present invention." It can also be said that the method for producing the powder or granular material according to the present invention includes the method for producing the agglomerates according to the present invention as one step.

[0192] The present method for producing powder and granules has the above-mentioned configuration, and therefore has the advantage of being able to produce powder and granules with high bulk density and circularity.

[0193] Each step in the method for producing the powder or granule will be explained below, but the details in the section [2. Method for producing aggregates] will be used as appropriate for matters other than those explained in detail below.

[0194] (3-1. Recovery process) The recovery step is a step of recovering the aggregates obtained by the present method for producing an aggregate. In the recovery step, the method for recovering the aggregates is not particularly limited, and various methods can be applied. For example, the aggregates can be recovered by allowing the aggregates that have descended in the gas phase of the container in which the contact step was carried out to descend into a receiving tank containing an aqueous phase that is installed at the bottom of the container, removing the slurry containing the aggregates from the receiving tank, and separating the aggregates from the slurry.

[0195] The method for separating the aggregates from the slurry (separation method) is not particularly limited, and examples thereof include centrifugal dehydration, static separation, filtration dehydration, compression dehydration, and water evaporation. The equipment used to implement the various separation methods can be appropriately selected according to the desired separation method. For example, a screw press, a roller press, a belt screen, a vibrating sieve, a multi-plate vibrating filter, a vacuum dehydrator, a pressure dehydrator, a belt press, a centrifugal dehydrator, and the like can be used.

[0196] The recovery step preferably further includes a heat treatment step of heat-treating the slurry containing the aggregates before separating the aggregates from the slurry. The temperature for heat-treating the slurry is not particularly limited, but is, for example, 60°C to 98°C, more preferably 60°C to 95°C. The time for heat-treating the slurry is not particularly limited, but is, for example, preferably 30 seconds to 30 minutes, more preferably 1 minute to 20 minutes, and even more preferably 1 minute to 10 minutes. Heat-treating the slurry containing the aggregates can increase the bulk density of the aggregates, thereby producing a powder with a higher bulk density. The heat treatment of the slurry may be performed on the slurry in the receiving tank or after the slurry is removed from the receiving tank. The method for heat treatment is also not particularly limited, but examples include a method of supplying high-temperature (e.g., 130°C) steam to the slurry. When heat-treating the slurry in the receiving tank, heat treatment can also be performed by adjusting the temperature of a solution containing a coagulant in the receiving tank (described later) to the above range.

[0197] The aqueous phase in the receiving tank may be water, but is preferably a solution containing the coagulant, as this allows for more reliable coagulation of insufficiently coagulated aggregates. When a solution containing a coagulant is used as the aqueous phase, the coagulant concentration of the solution is not particularly limited, but is preferably 0.01 wt% to 15.00 wt%, more preferably 0.05 wt% to 10 wt%, and even more preferably 0.10 wt% to 5.00 wt%. When the aqueous phase used in the recovery step is a solution containing a coagulant, the coagulant concentration of the solution may be the same as that of the coagulant solution used in the contact step, but is preferably lower than that of the coagulant solution, because this has the advantages of reducing the production costs of the aggregates and granules, reducing coagulant-derived impurities that may be contained in the aggregates and granules, and ensuring storage stability.

[0198] When a solution containing a coagulant is used as the aqueous phase of the receiving tank, the coagulant solution in the contact step may descend into the receiving tank and mix with the aqueous phase (coagulant-containing solution), which may unintentionally change the coagulant concentration of the aqueous phase (coagulant-containing solution). For example, if the coagulant concentration in the aqueous phase (coagulant-containing solution) is lower than the coagulant concentration in the coagulant solution used in the contact step, the coagulant concentration in the aqueous phase (coagulant-containing solution) will increase. It is preferable that the coagulant concentration in the aqueous phase (coagulant-containing solution) in the recovery step be controlled within a desired range. The method of control is not particularly limited. For example, when the contact step is performed while a flow-down operation is being performed, the coagulant concentration in the aqueous phase (coagulant-containing solution) can be controlled within a desired range by flowing the flow-down water into the receiving tank.

[0199] The temperature of the solution containing the coagulant in the receiving tank in the recovery step is not particularly limited, but from the viewpoint of preventing the aggregates from fusing together and more sufficiently coagulating insufficiently coagulated aggregates, the temperature is preferably 20°C to 100°C, more preferably 40°C to 100°C, and even more preferably 60°C to 100°C.

[0200] (3-2. Drying process) The drying process is a process of drying the aggregates recovered in the recovery process. By drying the aggregates, moisture derived from the latex contained in the aggregates, the coagulant solution, and the aqueous phase in the receiving tank is removed, and it can also be said that this process promotes fusion between the polymer microparticles within the aggregates.

[0201] In the drying step, the method for drying the aggregates is not particularly limited, and known methods can be used. For example, the aggregates may be dried by heat treatment.

[0202] When the aggregates are dried by heat treatment, the temperature for heat treatment of the aggregates is not particularly limited, but is preferably, for example, 40° C. to 120° C., more preferably 60° C. to 120° C., more preferably 60° C. to 100° C., and even more preferably 65° C. to 95° C. The time for heat treatment of the aggregates is, for example, preferably 1 minute to 90 minutes, more preferably 1 minute to 60 minutes, and even more preferably 5 minutes to 30 minutes.

[0203] When carrying out the heat treatment, it is preferable to suppress the aggregation of aggregates (aggregation between powder particles) during heating and during (after) drying. Therefore, it is preferable to add 0.5 to 3.0 parts by weight of hard non-elastomeric polymer latex (solids basis) to 100 parts by weight of the aggregate (solids basis) before the heat treatment. The hard non-elastomeric polymer latex may be added to the aggregate before the heat treatment. For example, it may be added to the aggregate recovered in the recovery step and mixed before the heat treatment, or it may be contained in the aqueous phase in the receiving tank in the recovery step and then added to the aggregate in the recovery step. By heat treating the aggregate to which the hard non-elastomeric polymer latex has been added under the above-mentioned heat treatment conditions, powder particles in which aggregation between powder particles is suppressed can be obtained.

[0204] The rigid non-elastic polymer may be a polymer obtained by polymerizing a small amount of a monomer capable of forming a rubber elastomer, such as butadiene (for example, 30% by weight or less of the total polymer, preferably 20% by weight or less, more preferably 10% by weight or less, and particularly 0% by weight). Examples of monomers that do not form rubber elastomers include: 1) alkyl (meth)acrylates having an alkyl group with 10 or less carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; 2) vinyl arenes, such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene, and vinyl cyanides, such as acrylonitrile; and 3) polyfunctional monomers, such as 1,3-butylene glycol di(meth)acrylate, allyl (meth)acrylate, diallyl phthalate, triallyl cyanurate, monoethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, divinylbenzene, and glycidyl (meth)acrylate. These monomers can be used alone or in appropriate combination.

[0205] [4. Powder] The powder obtained by the powder production method according to one embodiment of the present invention (hereinafter also referred to as "the present powder") has a high bulk density and circularity. The high bulk density of the powder allows the powder to be densely packed into transport tanks and bags, which is expected to reduce transportation costs. Furthermore, a high circularity of the powder improves the powder's flowability, allowing for smooth feeding into a feeder and reducing the risk of bridging (arch-shaped blockages). Furthermore, the present powder, which has a high bulk density and circularity, has the advantage of achieving a good dispersion state of polymer microparticles in a resin composition obtained by blending the present powder with a matrix resin, or in a molded or cured product thereof. In this specification, "powder (powder of polymer microparticles)" may refer to an aggregate of primary particles of polymer microparticles, in other words, secondary particles of polymer microparticles.

[0206] In this specification, the bulk density of the powder or granule is a value measured using a bulk density measuring device (JIS K-6720 model, manufactured by Kuramochi Scientific Instruments Manufacturing Co., Ltd.) based on JIS-K-6720:1999. The bulk density of the powder or granule is 0.39 g / cm. 3 It is preferable that the concentration is 0.40 g / cm or more. 3 More preferably, it is 0.41 g / cm or more. 3 The higher the bulk density of the powder or granule, the more densely the polymer fine particles are aggregated in the powder or granule. In particular, the bulk density of the powder or granule is 0.39 g / cm or more. 3 The bulk density of the powder or granules having the above mentioned value can be said to be a powder or granules having a sufficiently high bulk density. The upper limit of the bulk density of the powder or granules is not particularly limited, but it can be, for example, 1.0 g / cm. 3 It can be the following:

[0207] According to the method for producing an aggregate of one embodiment of the present invention, it is possible to obtain an aggregate with a high circularity. The circularity of the aggregate is preferably 0.80 or more, more preferably 0.81 or more. The circularity of the aggregate can be calculated from the perimeter and area of ​​the powder or granules captured in an electron microscope (SEM) image of the powder or granule. A method for measuring the circularity of the powder or granules will be described in detail in the Examples below. The closer the circularity of the powder or granules is to 1, the better the powder or granules' fluidity is, thereby enabling smoother feeding to a feeder and reducing the risk of bridging (arch-shaped blockages). Furthermore, a good dispersion state of polymer microparticles can be achieved in a resin composition obtained by blending the present powder or granules with a matrix resin, or in a molded or cured product thereof.

[0208] The volume average particle size of the present powder or granule is not particularly limited, but is preferably 50 μm to 500 μm, more preferably 100 μm to 400 μm, and even more preferably 200 μm to 350 μm. [Example]

[0209] Hereinafter, one embodiment of the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these. One embodiment of the present invention can be practiced with appropriate modifications within the scope of the above-mentioned or below-mentioned gist, and all such modifications are included in the technical scope of the present invention.

[0210] [Evaluation method] The evaluation methods for the agglomerates and powders obtained in the Examples and Comparative Examples are described below. Measurements of circularity and bulk density were performed on a mixture of a powder obtained from agglomerates obtained by recovering in a receiving tank the agglomerates that had descended through the gas phase of the vessel, and a powder obtained from agglomerates obtained by recovering in a receiving tank the agglomerates that had adhered to the inner wall surface of the coagulation vessel through a flow-down operation. Measurements of recovery rate were performed on agglomerates obtained without recovering the agglomerates that had adhered to the inner wall surface of the coagulation vessel (i.e., only the agglomerates obtained by recovering in a receiving tank the agglomerates that had descended through the gas phase of the vessel).

[0211] (Measurement of volume average particle size) The volume average particle size (Mv) of the diene rubber (elastomer) or graft copolymer dispersed in the latex was measured using a Nanotrac Wave II-EX150 (Microtrackbell Corporation). The latex was diluted with deionized water and used as the measurement sample. The measurement was performed by inputting the refractive index of water and the diene rubber (elastomer) or graft copolymer obtained in each production example, measuring for 120 seconds, and adjusting the sample concentration so that the loading index was within the range of 1 to 10.

[0212] (Circularity measurement) A scanning electron microscope (SEM, S-3000N manufactured by Hitachi High-Technologies Corporation) was used to obtain electron microscope photographs (SEM images) of the obtained powder or granules, and the circularity was measured using general-purpose image processing software (product name: NANO HUNTER NS2K-PRO / LT manufactured by Nano Systems Co., Ltd.). Specifically, the SEM images were imported into the image processing program of the general-purpose image processing software, and the perimeter and area of ​​the powder or granules were measured. The circularity was calculated from the obtained perimeter and area according to the following formula. The circularity was calculated for 100 randomly selected powder or granules, and the arithmetic mean value was taken as the circularity.

[0213] (Circularity) = 4π × (area) / (perimeter) 2 .

[0214] (Measurement of bulk density) The bulk density of the resulting powder was measured using a bulk density measuring device (JIS K-6720 model, manufactured by Kuramochi Scientific Instruments Manufacturing Co., Ltd.).

[0215] (Measurement of recovery rate) The recovery rate was calculated from the ratio of the weight of the aggregates (solid content) recovered in the lower receiving tank to the weight of the latex solid content (polymer fine particles) charged into the coagulation tank.

[0216] [Production Example 1: Production of emulsion polymerized latex of graft copolymer (G-1)] A 100 L polymerization vessel (pressure-resistant reactor equipped with a stirrer) was charged with 200 parts by weight of deionized water, and the interior of the vessel was degassed and purged with nitrogen. After purging with nitrogen, the vessel was charged with 2.5 parts by weight of sodium oleate, 0.002 parts by weight of ferrous sulfate (FeSO4·7H2O), 0.01 parts by weight of ethylenediaminetetraacetic acid (hereinafter referred to as EDTA)·2Na salt, 0.2 parts by weight of sodium formaldehyde sulfoxylate, 0.2 parts by weight of tripotassium phosphate, 100 parts by weight of butadiene, 0.5 parts by weight of divinylbenzene, and 0.1 parts by weight of diisopropylbenzene hydroperoxide under stirring.

[0217] Polymerization was carried out at 40°C for 10 hours, and then maintained at 60°C for 4 hours to obtain a diene rubber latex (R-1) containing a diene rubber (elastomer). The polymerization conversion rate was 98%, the volume average particle size of the elastomer was 0.08 μm, and the solids concentration of the diene rubber latex (R-1) was 32.5%.

[0218] Next, 215.4 parts by weight of the diene rubber latex (R-1) (70 parts by weight as solids (elastomer)), 50 parts by weight of water, 0.004 parts by weight of ferrous sulfate (FeSO4·7H2O), 0.005 parts by weight of EDTA·2Na salt, and 0.1 parts by weight of sodium formaldehyde sulfoxylate were charged into a glass reactor equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen inlet, and devices for adding monomers and emulsifiers. After mixing the charged raw materials, the temperature was raised to 60°C.

[0219] A mixture of 22 parts by weight of methyl methacrylate (MMA), 3 parts by weight of styrene, 5 parts by weight of butyl acrylate, and 0.1 parts by weight of cumene hydroperoxide was then continuously added to the glass reactor over a period of 4 hours. After an additional hour of polymerization, the polymerization was terminated to obtain emulsion-polymerized latex (G-1) containing graft copolymers as polymer microparticles. The volume-average particle diameter of the graft copolymer (polymer microparticles) was 0.23 μm. The concentration of polymer microparticles (solids concentration) in the emulsion-polymerized latex was 35% by weight.

[0220] [Production Example 2: Production of Hard Non-Elastic Polymer Latex (P-1)] 200 parts by weight of deionized water, 0.3 parts by weight of sodium oleate, 0.002 parts by weight of ferrous sulfate (FeSO4·7H2O), 0.005 parts by weight of EDTA·2Na salt, and 0.2 parts by weight of sodium formaldehyde sulfoxylate were added to a 100 L polymerization reactor (pressure-resistant reactor equipped with a stirrer). While stirring, the temperature inside the reactor was raised to 70°C. A monomer mixture consisting of 45 parts by weight of methyl methacrylate, 45 parts by weight of styrene, 10 parts by weight of 1,3-butylene glycol dimethacrylate, and 0.3 parts by weight of cumene hydroperoxide was then continuously added to the contents of the polymerization reactor over a period of 7 hours. During this period, 0.3 parts by weight of sodium oleate was added at 2 hours, 4 hours, and 6 hours after the start of the continuous addition. After the continuous addition of the monomer mixture was completed, the contents were further stirred for 2 hours to obtain a hard non-elastomeric polymer latex (P-1). The polymerization conversion was 99%.

[0221] Example 1: Production of aggregates and granules 1000 g of emulsion-polymerized latex (G-1) (the amount of polymer particles in the latex was 350 g, and this 350 g was defined as 100 parts by weight) was taken and adjusted to 25°C. The apparatus used was a cylindrical vessel with a vertical inner wall, with a receiving tank at the bottom equipped with an aqueous phase region for collecting aggregates formed in the gas phase region. The cylindrical vessel had a diameter of 80 cm and a height of 100 cm. A swirl-flow conical nozzle, a type of pressure nozzle, with a nozzle diameter of 0.6 mm was used as the nozzle (first nozzle) for spraying the emulsion-polymerized latex. The first nozzle was installed at the top of the vessel (tower top). The vertical distance between the first nozzle and the bottom of the vessel (the liquid level in the receiving tank) was 100 cm. The emulsion-polymerized latex was sprayed using the first nozzle at a spray pressure of 3.7 kg / cm. 2 The latex was sprayed vertically downward as droplets with a volume average droplet diameter of 200 μm in an atmosphere of 25°C (i.e., the temperature inside the container was 25°C). The shape of the spray cone of the sprayed latex was a full cone, and the tip angle was 50° to 60°.

[0222] At the same time, a calcium chloride aqueous solution with a calcium chloride concentration of 35% by weight was sprayed as a coagulant solution from a single-fluid nozzle (second nozzle) at a spray pressure of 4.0 kg / cm. 2 The coagulant solution was sprayed horizontally at a volume average droplet diameter of 1 μm to 100 μm. The temperature of the coagulant solution was 25°C.

[0223] The second nozzle was installed on the side (inner wall) of the container, 20 cm horizontally from the first nozzle, so as to spray the coagulant solution horizontally. The vertical distance between the first and second nozzles was 40 cm. The vertical distance between the second nozzle and the bottom of the container (the liquid level in the receiving tank) was 60 cm.

[0224] The amount of the coagulant solution sprayed was such that the amount of calcium chloride as the coagulant was 5 to 10 parts by weight per 100 parts by weight of polymer fine particles in the latex sprayed per unit time. The shape of the spray cone of the coagulant solution was hollow cone, and the tip angle was 70 to 90 degrees. By this operation, the latex sprayed in the gas phase was contacted with the coagulant solution to obtain an aggregate (contacting step).

[0225] A calcium chloride aqueous solution (25°C) with a calcium chloride concentration of 1% by weight was used as the aqueous phase in the receiving tank to recover the aggregates. In addition, to prevent fusion between the polymer microparticles, 1 part by weight of hard non-elastomeric polymer latex (P-1) was added to the calcium chloride aqueous solution in the receiving tank per 100 parts by weight of the polymer microparticles.

[0226] The aggregates formed by the contact of droplets of emulsion-polymerized latex with droplets of coagulant solution and descending through the gas phase of the vessel were then descended into the receiving tank containing the aqueous phase. Steam was blown into the slurry containing the aggregates in the receiving tank to raise the temperature of the slurry to 95°C, and the temperature of the slurry was maintained at 95°C for 5 minutes (heat treatment), after which the heat-treated slurry was recovered from the receiving tank (recovery step). The recovered slurry after the heat treatment was dehydrated by suction filtration, and the obtained aggregates were dried in a dryer at 60°C for 1 hour or more to obtain powder particles (drying step). The circularity and bulk density of the obtained powder particles, as well as the recovery rate of the aggregates from the polymer fine particles in the latex, were measured, and the results are shown in Table 1.

[0227] The contacting step was carried out by constantly flowing down water (flowing down operation) along the inner wall surface of the vessel in an amount equal to the amount of latex sprayed per unit time. The flowing down water was collected in a receiving tank, and measurements of circularity and bulk density were carried out on a powder or granule obtained from a mixture of agglomerates that had fallen in the gas phase of the vessel and agglomerates that had adhered to the inner wall surface of the coagulation vessel and were collected in the receiving tank by the flowing down operation. The measurement of recovery rate was carried out on only the agglomerates that had fallen in the gas phase of the vessel, without collecting the flowing down water in the receiving tank.

[0228] Comparative Example 1: Production of aggregates and granules The same method as in Example 1 was used to obtain aggregates and granules, except that a two-fluid nozzle was used instead of a one-fluid nozzle as the nozzle (second nozzle) used to spray the coagulant solution, the coagulant solution was mixed with air, and the coagulant solution was sprayed at an air flow rate of 60 L / min with droplet diameters of 0.1 to 30 μm. The circularity and bulk density of the obtained granules, as well as the recovery rate of the aggregates from the polymer fine particles in the latex, were measured and the results are shown in Table 1.

[0229] [Table 1] [Industrial Applicability]

[0230] According to one embodiment of the present invention, an aggregate can be produced from a latex containing polymer microparticles, which can be used to produce powder particles with excellent powder properties. Therefore, the production method according to one embodiment of the present invention can be suitably used as one step in the production of resin compositions that are preferably used in applications such as adhesives, coating materials, binders for reinforcing fibers, composite materials, 3D printer modeling materials, sealants, electronic substrates, ink binders, wood chip binders, rubber chip binders, foam chip binders, foundry binders, rock consolidation agents for flooring and ceramics, and urethane foam.

Claims

1. a contacting step of spraying and / or dropping a latex of polymer fine particles in a vertical direction and spraying a coagulant solution in a horizontal direction to bring the droplets of the latex into contact with the droplets of the coagulant solution, In the contacting step, a two-fluid nozzle with an air flow rate set to less than 60 L / min is used to spray the coagulant solution, and / or A method for producing an agglomerate, wherein a single-fluid nozzle is used to spray the coagulant solution.

2. The method for producing an agglomerate according to claim 1 , wherein the contacting step uses a one-fluid nozzle to spray the coagulant solution.

3. The method for producing an aggregate according to claim 1 or 2, wherein the droplets of the coagulant solution have a volume average droplet diameter of 1 μm to 100 μm.

4. 4. The method for producing an aggregate according to claim 1, wherein a concentration of the polymer fine particles in the latex is 10% by weight to 55% by weight based on 100% by weight of the latex.

5. 5. The method for producing an aggregate according to claim 1, wherein the amount of the coagulant sprayed is 1 to 30 parts by weight per 100 parts by weight of the total amount of the polymer fine particles sprayed and dropped.

6. 6. The method for producing an aggregate according to claim 1, wherein the polymer fine particles have an elastomer and a graft portion graft-bonded to the elastomer.

7. The method for producing an aggregate according to claim 6 , wherein the elastic body comprises at least one rubber selected from the group consisting of diene-based rubber, (meth)acrylate-based rubber, and organosiloxane-based rubber.

8. 8. The method for producing an aggregate according to claim 6 or 7, wherein the graft portion is composed of a polymer containing, as a structural unit, a structural unit derived from one or more monomers selected from the group consisting of an aromatic vinyl monomer, a vinyl cyan monomer, and a (meth)acrylate monomer.

9. a recovery step of recovering the aggregate obtained by the method for producing an aggregate according to any one of claims 1 to 8; a drying step of drying the collected aggregate; A method for producing a powder of polymer fine particles, comprising:

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