Method for producing granules

Abstract

To provide a method for producing granules that can produce granules with a low content of residual impurities and high bulk specific gravity.SOLUTION: A method for producing granules comprises: a coagulation step of stirring a suspension containing polymer particles and a coagulant to coagulate the polymer particles, thereby yielding aggregates; a heat treatment step of heating the aggregates at a heat treatment temperature of 60°C to 90°C; a washing step of washing the aggregates with a specific amount of washing water; and a granulation step of forming the aggregates into granules using a granulator.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing granules. [Background technology]

[0002] Polymer particles are used as resin modifiers such as impact modifiers, etc. For the purpose of improving the handleability of polymer particles or compositions containing polymer particles, techniques for pelletizing (granulating) them are known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-159788 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional techniques are not sufficient in terms of the bulk density of the granules and the amount of remaining impurities, and there is room for further improvement.

[0005] One embodiment of the present invention has been made in consideration of the above-mentioned problems, and its object is to provide a new method for producing granules that can provide granules with a small amount of residual impurities and a high bulk density. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have completed the present invention.

[0007] That is, one embodiment of the present invention includes the following configuration. [1] A method for producing granules, comprising: a coagulation step of coagulating polymer particles by stirring a suspension containing polymer particles and a coagulant to obtain agglomerates of the polymer particles; a heat treatment step of heat-treating the agglomerates obtained in the coagulation step; a washing step of washing the agglomerates after the heat treatment step; and a granulation step of forming the agglomerates after the washing step into granules using a granulator, wherein the heat treatment temperature in the heat treatment step is 60°C to 90°C, and the washing step involves washing the agglomerates using washing water in an amount of 3,000 parts by weight or less per 100 parts by weight of the polymer particles contained in the agglomerates. [2] The method for producing granules according to [1], wherein the median diameter of the aggregates after the heat treatment step is 1.0 μm to 200.0 μm. [3] The method for producing granules according to [1] or [2], wherein the shape of the granules is one or more selected from the group consisting of cylindrical, prismatic, and spherical. [4] The method for producing granules according to any one of [1] to [3], wherein the diameter of the granules is 0.5 mm to 5.0 mm and the length of the granules is 0.5 mm to 20.0 mm. [5] The bulk density of the granules is 0.350 g / cm 3 The method for producing granules according to any one of [1] to [4] above. [6] A method for producing granules according to any one of [1] to [5], wherein the polymer particles are a rubber-containing graft copolymer having an elastomer and a graft portion graft-bonded to the elastomer. [7] The method for producing granules according to [6], wherein the graft portion contains one or more structural units selected from the group consisting of aromatic vinyl units, vinyl cyan units, and (meth)acrylate units. [8] The method for producing granules according to [6] or [7], wherein the elastic body is composed only of (meth)acrylate rubber. [9] The method for producing granules according to any one of [1] to [8], wherein the coagulant is a divalent or higher salt. [Effects of the Invention]

[0008] According to one embodiment of the present invention, it is possible to provide a novel method for producing granules that can provide granules with a small amount of residual impurities and a high bulk density. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a view of an example of an agitating impeller used in one embodiment of the present invention, viewed vertically from above. [Figure 2] FIG. 2 is a view of the stirring blade shown in FIG. 1 as seen from the horizontal direction. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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)."

[0011] In this specification, a "structural unit derived from an X monomer" contained in a polymer, copolymer, or resin may be referred to as an "X unit."

[0012] In this specification, the terms "cylindrical", "prismatic", and "spherical" may include not only the exact terms "cylindrical", "prismatic", and "spherical", but also "approximately cylindrical", "approximately prismatic", and "approximately spherical".

[0013] In this specification, the terms "uniform" and "constant" may include not only the exact terms "uniform" and "constant", but also "approximately uniform" and "approximately constant", respectively.

[0014] 1. Granule manufacturing method A method for producing granules according to one embodiment of the present invention comprises a coagulation step of coagulating the polymer particles by stirring a suspension containing the polymer particles and a coagulant to obtain agglomerates of the polymer particles, a heat treatment step of heat-treating the agglomerates obtained in the coagulation step, a washing step of washing the agglomerates after the heat treatment step, and a granulation step of forming the agglomerates after the washing step into granules using a granulator, wherein the heat treatment temperature in the heat treatment step is 60°C to 90°C, and the washing step washes the agglomerates using washing water in an amount of 3000 parts by weight or less per 100 parts by weight of the polymer particles contained in the agglomerates.

[0015] In this specification, the "method for producing granules according to one embodiment of the present invention" may also be referred to as the "present production method."

[0016] The present manufacturing method has the above-described configuration, and therefore has the advantage of being able to provide a manufacturing method for granules that can provide granules with a small amount of residual impurities and a high bulk density. The "amount of residual impurities" in granules refers to the amount of, for example, chlorine (Cl) element in the granules. Methods for measuring the amount of residual impurities (e.g., chlorine (Cl) element) in granules and methods for measuring the bulk density of granules will be described in detail in the Examples below.

[0017] The granules obtained by this production method can be mixed with (blended into) any resin (matrix resin) such as a thermoplastic resin to impart desired physical properties to the resulting resin composition or a molded or cured product obtained from the resin composition. In other words, the granules obtained by this production method can also be called a "modifier."

[0018] The raw materials (components) and equipment used in this production method will be described in detail below, followed by an explanation of each step of this production method.

[0019] (1-1. Container) The container used in this manufacturing method is not particularly limited.

[0020] Examples of materials for the container include general structural rolled steel (also referred to as SS material), stainless steel (also referred to as SUS material), other metal materials, plastic materials, and glass materials. Among these, stainless steel materials and surface-coated general structural rolled steel materials are preferred from the viewpoint of strength and / or corrosion resistance.

[0021] Examples of the shape of the container include a cylindrical shape, a spindle shape, a conical shape, a spherical shape, and a shape formed by combining these shapes.

[0022] In this production method, the vessel is preferably equipped with a stirring blade. This configuration has the advantages of (i) improving the mixing effect of the polymer particles and the coagulant in the suspension in the coagulation step, and (ii) uniformly supplying heat to the aggregates in the heat treatment step. As a result, this production method has the advantages of (i) being able to provide granules with superior washability, and (ii) being able to provide granules with a higher bulk density.

[0023] (1-2. Mixing blade) The agitator blade includes an agitator shaft, one or more agitator blades attached to the agitator shaft, and an agitator base for attaching the agitator blade to the agitator shaft. The agitator blade of the agitator blade may be attached to the agitator shaft by attaching a member to which the agitator blade is attached to the agitator shaft, or may be attached directly to the agitator shaft. In this specification, when the agitator blade is attached to the agitator shaft via the member, the member is referred to as the "agitator base." Also, when the agitator blade is attached directly to the agitator shaft, the part of the agitator shaft to which the agitator blade is attached is considered to be the "agitator base." In this specification, the term "agitator blade" refers to the part attached to the agitator base that protrudes beyond the agitator base and is the part that, when rotated, substantially collides with the solvent and polymer particles and can agitate the solvent and polymer particles.

[0024] In this specification, an impeller having an impeller with an inclination angle greater than 0 degrees is also referred to as an "inclined impeller." On the other hand, in this specification, an impeller having no inclination angle, in other words, an impeller having an inclination angle of 0 degrees, is also referred to as a "non-inclined impeller." The impeller may be a non-inclined impeller, an inclined impeller, or a combination thereof.

[0025] In this specification, the "inclination angle" of the agitator blade refers to the angle θ formed at the top of plane S perpendicular to the axial direction of the agitator shaft when a straight line L is drawn connecting the highest and lowest points in the vertical direction at the part of the agitator blade that contacts the agitator base, and which is also formed in the direction of rotation of the agitator shaft.

[0026] The "inclination angle" of the impeller will be explained in more detail using the drawings. FIG. 1 is a view of an example of an impeller used in embodiment 1 of the present invention, viewed vertically from above. The impeller 100 shown in FIG. 1 comprises an impeller shaft 10 and an impeller 1 attached to the impeller shaft 10. In the impeller 100, the impeller shaft 10 extends vertically. Therefore, in FIG. 1, the impeller shaft 10 is shown with a cross-sectional shape perpendicular to the axial direction of the impeller shaft. In the impeller 100, the impeller 1 is attached directly to the impeller shaft 10. In FIG. 1, the rotation direction of the impeller 100 is indicated by a solid arrow. FIG. 2 is a view of the impeller 100 shown in FIG. 1, viewed horizontally. In the impeller 100 in FIG. 2, the portion of the impeller shaft 10 to which the impeller 1 is attached corresponds to the impeller base, but the impeller base is not shown. In FIG. 2, the dashed line L represents a line connecting the highest and lowest points in the vertical direction at the portion of the agitator impeller 1 that contacts the agitator base, and the dotted line S represents a plane perpendicular to the axial direction of the agitator shaft 10. Because the agitator shaft 10 of the agitator impeller 100 extends vertically, the plane S can also be considered a horizontal plane. As shown in FIG. 2, of the angles formed by the line L and the plane S, the angle θ formed above the plane S and facing the direction of rotation of the agitator shaft is referred to herein as the "tilt angle" of the agitator impeller. As shown in FIG. 2, when the tilt angle θ is an acute angle, the agitator impeller 1 can be said to be configured to be tilted θ degrees toward the direction of rotation of the agitator impeller 100. In other words, the agitator impeller 1 in FIG. 2 has a tilt angle θ. Although the agitator impeller 100 has one agitator blade 1 on one side of the agitator shaft 10, the number of agitator blades that the agitator impeller has and the position on the agitator shaft at which the agitator blade is attached are not limited.

[0027] The inclined stirring blade is not particularly limited, and any known inclined stirring blade can be used. Examples of inclined stirring blades include inclined paddle blades, propeller blades, screw blades, and helical ribbon blades. Among these, inclined paddle blades, propeller blades, and screw blades are preferred because they reduce adhesion of resin (polymer particles) to the blades and require less power, with inclined paddle blades and propeller blades being more preferred and inclined paddle blades being particularly preferred.

[0028] In the inclined agitating blade, the inclination angle of the agitating blade is not particularly limited as long as it is greater than 0 degrees, but is preferably 20 degrees to 70 degrees, more preferably 30 degrees to 60 degrees, even more preferably 35 degrees to 55 degrees, and particularly preferably 40 degrees to 50 degrees. This configuration has the advantage of providing a high mixing effect even with low power requirements.

[0029] The non-inclined impeller is not particularly limited, and any known inclined impeller can be used. Examples of non-inclined impellers include H-blade, flat paddle impeller, disk turbine impeller, Pfaudler impeller, anchor impeller, Max Blend impeller, Super Mix, and Full Zone. Among these, H-blade, flat paddle impeller, disk turbine impeller, Pfaudler impeller, anchor impeller, and Max Blend impeller are preferred because they provide a high mixing effect even with low power requirements, with H-blade, disk turbine impeller, anchor impeller, and Max Blend impeller being more preferred, with H-blade and Max Blend impeller being even more preferred, and H-blade being particularly preferred.

[0030] Unless otherwise specified, the following description will be given of the agitation shaft, agitation blades and agitation base for both inclined agitation blades and non-inclined agitation blades.

[0031] The shapes of the stirring shaft and the stirring base are not particularly limited, and examples thereof include a cylindrical shape, a square shape, a conical shape, etc. Among these, a cylindrical shape is more preferable from the viewpoint of not disturbing the flow in the center.

[0032] The materials for the agitator shaft, agitator blades, and agitator base are not particularly limited, and examples thereof include SS material, SUS material, other metal material, plastic material, glass material, etc. Among these, stainless steel material and surface-coated general structural rolled steel material are preferred from the viewpoint of strength and / or corrosion resistance.

[0033] The surface structure of the stirring blade is not particularly limited. The surface of the stirring blade is preferably smooth, but may not be smooth, for example, may have irregularities or may be wavy. The stirring blade may also have holes penetrating the stirring blade. In order to achieve excellent solution mixing properties, it is preferable that the shape of the stirring blade is both smooth and irregular.

[0034] The shape of the stirring blade is not particularly limited, but examples thereof include a rectangular shape, a trapezoidal shape, a polygonal shape, an arc shape, etc. Among these, the rectangular shape and the trapezoidal shape are preferred because they provide good solution mixing properties and are easy to process.

[0035] In one embodiment of the present invention, the number of stirring blades in the stirring impeller is not particularly limited, but is preferably 2 or more, more preferably 2 to 6, and even more preferably 2 to 4. The number of stirring blades in the stirring impeller may be 4 to 6. This configuration has the advantage of requiring less power for stirring.

[0036] One agitator blade may behave like two agitator blades by having a shape that is point-symmetrical across the agitator shaft. Also, when an agitator blade has two or more agitator blades, the shapes of the agitator blades are preferably the same as each other, but may be different from each other. Also, when an agitator blade has two or more agitator blades, the agitator blades are preferably arranged evenly with respect to the central axis of the agitator base, but may be arranged unevenly. When an agitator blade has multiple agitator blades (two or more), the agitator base serves to connect the multiple agitator blades.

[0037] The stirring shafts of the inclined stirring blades and the non-inclined stirring blades provided in the vessel may or may not be vertical (which can also be said to be the depth direction of the vessel). In a preferred aspect of one embodiment of the present invention, since this improves the mixability of the solution, (i) it is preferable that the stirring shaft of the non-inclined stirring blade is vertical and / or that the stirring shaft of the inclined stirring blade is vertical, and (ii) it is preferable that both the stirring shaft of the non-inclined stirring blade and the stirring shaft of the inclined stirring blade are vertical.

[0038] The vessel may be equipped with two or more inclined agitator blades. When the vessel is equipped with two or more inclined agitator blades, the agitation axes of the two or more inclined agitator blades may or may not coincide. When the agitation axes of the two or more inclined agitator blades coincide, the inclined agitator blades may share one agitator shaft, and two or more agitator bases may be attached to one agitator shaft.

[0039] In order to improve the mixing properties of the solution, it is preferable that the vessel is provided with two or more inclined stirring blades, and that the stirring axes of all of the inclined stirring blades provided in the vessel are vertical.

[0040] The vessel may have two or more non-inclined agitator blades. When the vessel has two or more non-inclined agitator blades, the agitation axes of the two or more non-inclined agitator blades may or may not coincide. When the agitation axes of the two or more non-inclined agitator blades coincide, the non-inclined agitator blades may share a single agitator shaft, and two or more agitator bases may be attached to the single agitator shaft.

[0041] It is preferable that the vessel has two or more non-inclined stirring blades, and that the stirring axes of all of the non-inclined stirring blades provided on the vessel are vertical, as this will result in better mixing of the solution.

[0042] A non-inclined impeller and an inclined impeller may share a single agitation shaft and be provided in a vessel as a single impeller. Alternatively, an impeller having an impeller with an inclination angle of 0 degrees and an impeller with an inclination angle greater than 0 degrees may be used. An "impeller having an impeller with an inclination angle of 0 degrees and an impeller with an inclination angle greater than 0 degrees" is both a non-inclined impeller and an inclined impeller. Therefore, an "impeller having an impeller with an inclination angle of 0 degrees and an impeller with an inclination angle greater than 0 degrees" is sometimes referred to as a "non-inclined-inclined impeller." When a vessel is provided with a non-inclined-inclined impeller, the vessel is considered to be provided with both a non-inclined impeller and an inclined impeller.

[0043] (1-3. Suspension) The suspension contains polymer particles and a coagulant. The suspension can be obtained, for example, by mixing a latex (aqueous latex) containing polymer particles with a coagulant or a coagulant solution.

[0044] (1-3-1. Polymer particles) The polymer particles are not particularly limited in other aspects as long as they are fine particles obtained by polymerization.

[0045] The polymer particles are preferably rubber-containing graft copolymers having an elastomer and a graft portion graft-bonded to the elastomer. When the polymer particles are graft copolymers, the polymer particles have the advantage of exhibiting favorable behavior in this production method. Hereinafter, one embodiment of the present invention will be described using the case where the polymer particles are rubber-containing graft copolymers as an example.

[0046] (elastic body) 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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 desired effects of the polymer particles containing diene rubber can be more effectively achieved. 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.

[0052] In one embodiment of the present invention, the elastomer preferably contains 30% by weight or more of diene rubber, more preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, even more preferably 70% by weight or more, preferably 80% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably 100% by weight, based on 100% by weight of the elastomer. In other words, the elastomer is most preferably composed solely of diene rubber.

[0053] In one embodiment of the present invention, the elastomer contains butadiene rubber and / or butadiene-styrene rubber, and preferably contains a total of 30% by weight or more of butadiene rubber and butadiene-styrene rubber in 100% by weight of the elastomer, more preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, more preferably 70% by weight or more, preferably 80% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably 100% by weight. In other words, the elastomer is most preferably composed of only butadiene rubber, or only butadiene-styrene rubber, or only butadiene rubber and butadiene-styrene rubber.

[0054] 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.

[0055] 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.

[0056] 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, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred, with methyl (meth)acrylate and butyl (meth)acrylate being more preferred.

[0057] 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, more preferably one or more selected from the group consisting of methyl (meth)acrylate rubber and butyl (meth)acrylate rubber, even more preferably one or more selected from the group consisting of butyl (meth)acrylate rubber, and particularly preferably butyl acrylate. Methyl (meth)acrylate rubber is a rubber containing 50% by weight or more of methyl (meth)acrylate units per 100% by weight of rubber, ethyl (meth)acrylate rubber is a rubber containing 50% by weight or more of ethyl (meth)acrylate units per 100% by weight of rubber, butyl (meth)acrylate rubber is a rubber containing 50% by weight or more of butyl (meth)acrylate units per 100% by weight of rubber, butyl acrylate rubber is a rubber containing 50% by weight or more of butyl acrylate units per 100% by weight of rubber, and 2-ethylhexyl (meth)acrylate rubber is a rubber containing 50% by weight or more of 2-ethylhexyl (meth)acrylate units per 100% by weight of rubber. This configuration lowers the glass transition temperature (Tg) of the elastomer, resulting in polymer particles and resin compositions with 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.

[0058] In one embodiment of the present invention, the elastomer preferably contains 30% by weight or more of (meth)acrylate rubber, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, preferably 80% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably 100% by weight. In other words, it is most preferable that the elastomer is composed solely of (meth)acrylate rubber. This configuration has the advantage of being able to provide a molded or cured product with a good balance of physical properties such as color tone, tensile strength, impact resistance, dispersibility, and compatibility. Specifically, depending on the type of resin (matrix resin) into which the granules are to be blended, when the elastomer contains 60% by weight or more of a (meth)acrylate rubber out of 100% by weight of the elastomer, compared to when the elastomer contains a large amount (for example, 60% by weight or more out of 100% by weight of the elastomer) of a diene rubber (for example, polybutadiene rubber), the resulting resin composition or a molded or cured product obtained from the resin composition has the advantage of being better in color, tensile strength, impact resistance, dispersibility and / or compatibility.

[0059] In one embodiment of the present invention, the elastomer preferably contains 30% by weight or more of butyl (meth)acrylate rubber, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, preferably 80% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably 100% by weight. In other words, it is most preferable that the elastomer is composed solely of butyl (meth)acrylate rubber. This configuration has the advantage of being able to provide a molded or cured product with a good balance of physical properties such as color tone, tensile strength, impact resistance, dispersibility, and compatibility. Specifically, depending on the type of resin (matrix resin) into which the granules are to be blended, when the elastomer contains 60% by weight or more of butyl (meth)acrylate rubber out of 100% by weight of the elastomer, compared to when the elastomer contains a large amount (for example, 60% by weight or more out of 100% by weight of the elastomer) of diene rubber (for example, polybutadiene rubber), the resulting resin composition or the molded or cured product obtained from the resin composition has the advantage of being better in color, tensile strength, impact resistance, dispersibility and / or compatibility.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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 resin composition containing the resulting 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.

[0064] In one embodiment of the present invention, the elastomer preferably contains 30% by weight or more of organosiloxane-based rubber, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably 100% by weight. In other words, it is most preferable that the elastomer is composed solely of organosiloxane-based rubber. According to this configuration, the resulting resin composition can provide a molded article or cured product with excellent heat resistance.

[0065] (elastic cross-linked structure) From the viewpoint of maintaining the dispersion stability of the polymer particles 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.

[0066] 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.

[0067] 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.

[0068] Among the above-mentioned 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 (for example, 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.

[0069] (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.

[0070] (elastic body ratio) The proportion of the elastomer in the polymer particles 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 particles. 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 particles do not easily aggregate, so the resin composition does not become highly viscous, and as a result, the resulting resin composition can be easy to handle.

[0071] In one embodiment of the present invention, the "elastic body" of the polymer particles may consist of only one type of elastomer having the same composition of constitutional units.

[0072] (graft area) The graft moiety preferably contains one or more structural units selected from the group consisting of aromatic vinyl units, vinyl cyan units, and (meth)acrylate units. Graft moieties having such a structure can fulfill various roles. Examples of "various roles" include (i) improving the compatibility between the polymer particles and the matrix resin, (ii) improving the dispersibility of the polymer particles in the matrix resin, and (iii) enabling the polymer particles to be dispersed in the form of primary particles in a resin composition containing the matrix resin and the polymer particles (hereinafter simply referred to as "resin composition"), or in a molded or cured product thereof.

[0073] Specific examples of monomers from which aromatic vinyl units are derived include styrene, α-methylstyrene, p-methylstyrene, and divinylbenzene.

[0074] Specific examples of monomers from which vinylcyan units are derived include acrylonitrile and methacrylonitrile.

[0075] Specific examples of monomers from which (meth)acrylate units are derived 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.

[0076] 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.

[0077] The graft portion preferably contains 10 to 95% by weight of aromatic vinyl units, vinylcyan units, and (meth)acrylate units in total, based on 100% by weight of the graft portion, 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.

[0078] 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 particles to be chemically bonded to the matrix resin in the resin composition. This allows the polymer particles to be maintained in a well-dispersed state without agglomeration in the resin composition, or in a molded or cured product thereof.

[0079] 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.

[0080] 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).

[0081] 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.

[0082] The above-mentioned monomers having a reactive group may be used alone or in combination of two or more.

[0083] 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.

[0084] 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.

[0085] 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 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 particles in the matrix resin is improved.

[0086] 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.

[0087] Specific examples of the polyfunctional monomer are the same as those explained in the section (Elastomer) above, and therefore the explanation therefor is omitted here.

[0088] Among the 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] The graft portion may cover at least a portion of the elastic body, or may cover the entire elastic body. A portion of the graft portion may penetrate into the interior of the elastic body. It is preferred that at least a portion of the graft portion covers at least a portion of the elastic body. In other words, it is preferred that at least a portion of the graft portion is present on the outermost side of the polymer particle.

[0093] The polymer particles may have 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 a core layer) and a layer of the graft portion is formed on the outside of the elastomer as the outermost layer (also referred to as a shell layer). A structure in which the elastomer forms the core layer and the graft portion forms the shell layer can also be called a core-shell structure. In one embodiment of the present invention, the polymer particles may have a core-shell structure.

[0094] (Surface crosslinked polymer) The rubber-containing graft copolymer preferably further comprises a surface-crosslinked polymer in addition to the elastomer and the graft portion grafted to the elastomer. In other words, the polymer particles preferably further comprise a surface-crosslinked polymer in addition to the elastomer and the graft portion grafted to the elastomer. Hereinafter, an embodiment of the present invention will be described using an example in which the polymer particles (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 the polymer particles, and (ii) the dispersibility of the polymer particles in the thermosetting resin 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 particles is reduced, resulting in less adhesion between the elastomers, thereby improving the dispersibility of the polymer particles.

[0095] When the polymer particles contain a surface-crosslinked polymer, the following effects can also be achieved: (i) the effect of reducing the viscosity of the resin composition, (ii) the effect of increasing the crosslink density in the elastomer, and (iii) the effect of 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.

[0096] 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.

[0097] 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.

[0098] The polymer particles 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 particles 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.

[0099] 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 portion. When the polymer particles contain a surface-crosslinked polymer, the graft portion may be (i) graft-bonded to an elastomer other than the surface-crosslinked polymer, (ii) graft-bonded to the 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 particles contain a surface-crosslinked polymer, the volume-average particle size of the elastomer mentioned above refers to the volume-average particle size of the elastomer containing the surface-crosslinked polymer.

[0100] A case (Case D) will be described where the polymer particles 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 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 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).

[0101] (Volume average particle size of polymer particles (Mv)) The volume average particle diameter (Mv) of the polymer particles 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 particles within the above range also offers the advantage of improving the dispersibility of the polymer particles in the matrix resin. In this specification, the term "volume average particle diameter (Mv) of the polymer particles" refers to the volume average particle diameter of the primary particles of the polymer particles, unless otherwise specified. The volume average particle diameter of the polymer particles can be measured using a dynamic light scattering particle size distribution analyzer or the like, using an aqueous latex containing the polymer particles as a sample.

[0102] (Method of producing polymer particles) An example of a method for producing polymer particles will be described below, taking as an example a case where the polymer particles are a rubber-containing graft copolymer having an elastomer and a graft portion grafted to the elastomer. The polymer particles can be produced, for example, by polymerizing the elastomer and then graft polymerizing a polymer that constitutes the graft portion to the elastomer in the presence of the elastomer.

[0103] The polymer particles can be produced by known methods, such as emulsion polymerization, suspension polymerization, and microsuspension polymerization. Specifically, the polymerization of the elastomer in the polymer particles and the polymerization of the graft moiety (graft polymerization) 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 particles. By producing polymer particles by emulsion polymerization, a latex (e.g., aqueous latex) containing polymer particles can be obtained. The emulsion polymerization method has the advantages of (i) easy compositional design of the polymer particles, and (ii) easy industrial production of polymer particles.

[0104] When emulsion polymerization is employed as the method for producing polymer particles, a known emulsifier (dispersant) can be used as the emulsifier (dispersant) for producing the polymer particles.

[0105] 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.

[0106] When a polyfunctional monomer is used in the polymerization of the elastomer or the graft portion for the purpose of introducing a crosslinked structure into the elastomer or the graft portion, 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 or the graft portion can be easily adjusted.

[0107] In the production of polymer particles, a surfactant may be used in addition to the above-mentioned components. The type and amount of the surfactant used are within known ranges.

[0108] In the production of polymer particles, conditions within known numerical ranges can be appropriately applied to the polymerization conditions such as polymerization temperature, pressure, and deoxidation.

[0109] A latex containing polymer particles can be obtained by the above-mentioned method for producing polymer particles. That is, the description in the section (Method for producing polymer particles) can be used as a description regarding the method for producing latex.

[0110] (1-3-2. Coagulant) The coagulant may be any substance capable of coagulating polymer particles in suspension. Examples of the coagulant include (i) inorganic acids (salts) and / or organic acids (salts), and (ii) polymeric coagulants. One of these coagulants may be used alone, or two or more may be used in combination. In this specification, inorganic acids (salts) refer to "inorganic acids and their salts," and organic acids (salts) refer to "organic acids and their salts."

[0111] Examples of inorganic acids include monovalent inorganic acids (e.g., (a) halogen acids such as chloric acid, bromic acid, and iodic acid, and (b) nitric acid), divalent inorganic acids (e.g., sulfuric acid), and trivalent inorganic acids (e.g., phosphoric acid).

[0112] Cationic elements or molecules capable of forming salts with inorganic acids include alkali metals, alkaline earth metals, transition metals (particularly iron and zinc), metals of Group 13 such as aluminum, and ammonium.

[0113] Examples of organic acids include monovalent organic acids (for example, formic acid, acetic acid, etc.) and divalent organic acids (for example, oxalic acid, malic acid, maleic acid, malonic acid, tartaric acid, etc.).

[0114] Examples of cationic elements that can form salts with organic acids include alkali metals and alkaline earth metals.

[0115] (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;

[0116] 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 particles.

[0117] 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.

[0118] The coagulant is preferably a divalent or higher salt, more preferably one or more selected from the group consisting of inorganic salts such as calcium chloride, magnesium chloride, magnesium sulfate, ammonium sulfate, ammonium chloride, ferrous sulfate, magnesium sulfate, zinc sulfate, copper sulfate, barium chloride, ferric chloride, magnesium chloride, ferric sulfate, aluminum chloride, aluminum sulfate, aluminum acetate, potassium alum, iron alum, etc., and organic acid salts such as calcium acetate and calcium formate, more preferably one or more selected from the group consisting of calcium chloride, magnesium chloride, aluminum sulfate, and magnesium sulfate, even more preferably one or more selected from the group consisting of calcium chloride, magnesium chloride, and magnesium sulfate, and particularly preferably calcium chloride.This configuration has the advantage of being able to form inexpensive and dense aggregates.

[0119] Furthermore, when the coagulant is a salt, there is no need to use containers, equipment, or stands made of acid-resistant materials to prevent rusting of the containers, equipment, or stands used in production, which has the advantage of reducing costs compared to when the coagulant is an acid. Furthermore, when the coagulant is a salt, there is no need to neutralize the wastewater, which has the advantages of reducing the environmental load, reducing the number of work steps, and reducing production costs compared to when the coagulant is an acid.

[0120] In 100% by weight of the coagulant used in the present production method, the total amount of inorganic acid and organic acid is preferably 5% by weight or less, more preferably 3% by weight or less, and particularly preferably 1% by weight or less.

[0121] The coagulant may be used as it is. That is, the coagulant itself may be added to the latex containing polymer particles to form a suspension. Alternatively, the coagulant may be dissolved in a solvent such as water to be used as a coagulant solution (coagulant aqueous solution). That is, the latex containing polymer particles may be mixed with the coagulant solution to form a suspension.

[0122] (1-3-3. Suspension) In this production method, the concentration of polymer particles in the suspension in each step is not particularly limited. A higher concentration of polymer particles in the suspension has the advantage of reducing the energy required for temperature increase (heating) in the subsequent heat treatment step. On the other hand, a lower concentration of polymer particles in the suspension has the advantages of (i) improving the fluidity of the suspension and facilitating its transportation, and (ii) reducing the viscosity of the suspension, facilitating the stirring of the suspension or reducing the energy required for stirring. From these perspectives, the concentration of polymer particles in the suspension in the coagulation step and / or heat treatment step is preferably 1.0 wt % to 60.0 wt %, more preferably 2.5 wt % to 55.0 wt %, even more preferably 5.0 wt % to 50.0 wt %, and particularly preferably 10.0 wt % to 40.0 wt %, relative to 100 wt % of the suspension.

[0123] The concentration of polymer particles in the suspension in the coagulation step and heat treatment step can be adjusted by (i) the concentration of polymer particles in the latex of polymer particles, and (ii) the amount of coagulant solution when a coagulant is used as the coagulant solution, etc. After mixing the latex of polymer particles with the coagulant solution, a solvent such as water may be further added to the resulting mixture to prepare a suspension having a desired concentration of polymer particles.

[0124] The concentration of polymer particles in the suspension in the heat treatment step may be the same as or different from the concentration of polymer particles in the suspension in the coagulation step. Usually, the concentration of polymer particles in the suspension in the heat treatment step may be the same as the concentration of polymer particles in the suspension in the coagulation step, or may be lower than the concentration of polymer particles in the suspension in the coagulation step. For example, if no solvent such as water is added to the suspension after the coagulation step, the concentration of polymer particles in the suspension in the coagulation step may be the same as the concentration of polymer particles in the suspension in the heat treatment step. On the other hand, by adding a solvent such as water to the suspension obtained in the coagulation step after the coagulation step, the concentration of polymer particles in the suspension in the heat treatment step may be lower than the concentration of polymer particles in the suspension in the coagulation step.

[0125] The concentration of the coagulant in the suspension is not particularly limited as long as it can coagulate the polymer particles in the suspension. The concentration of the coagulant in 100% by weight of the suspension is, for example, preferably 0.25% by weight to 5.0% by weight, more preferably 0.25% by weight to 2.0% by weight, even more preferably 0.25% by weight to 1.0% by weight, and particularly preferably 0.25% by weight to 0.8% by weight. This configuration allows the formation of dense aggregates, which are easy to wash. As a result, there is an advantage in that granules with a low amount of residual impurities can be obtained. Furthermore, there is an advantage in that the lower the concentration of the coagulant in the suspension, the fewer impurities there are in the granules.

[0126] (1-4.Coagulation process) By carrying out the coagulation step, an aggregate of polymer particles can be obtained. In the aggregate, the polymer particles can be considered to be primary particles. In other words, the aggregate can be considered to be secondary particles of the polymer particles, which are primary particles.

[0127] In the coagulation step, the coagulation temperature (temperature of the suspension) is not particularly limited, but is preferably 10°C to 80°C, more preferably 30°C to 70°C, even more preferably 40°C to 70°C, and particularly preferably 50°C to 70°C. A higher coagulation temperature (temperature of the suspension) has the advantage that a denser coagulate can be formed, and therefore, remaining impurities in the coagulate can be easily discharged into the solution. A lower coagulation temperature has the advantage that aggregation due to shear generated in the liquid feed pump can be suppressed, and the latex can be stabilized. Therefore, when the coagulation temperature is within the above-mentioned range, there is the advantage that a dense coagulate can be continuously and stably formed.

[0128] The coagulation temperature (temperature of the suspension) can be adjusted by the temperature of the latex of the polymer particles and the temperature of the coagulant solution used in the suspension. For example, when the temperature of the latex of the polymer particles and the temperature of the coagulant solution are the same, this temperature can be considered the temperature of the resulting suspension. The suspension may also be heated or cooled to bring the suspension to a desired temperature. The suspension may also be heated or cooled to maintain the suspension at a desired temperature during the coagulation process.

[0129] In the coagulation step, a higher stirring speed allows the suspension to be stirred more thoroughly, resulting in more uniform coagulation of the polymer particles and a smaller amount of fine powder and / or coarse particles. The higher the stirring speed, the more easily aggregates (secondary particles) with a sharper particle size distribution can be obtained. From this perspective, the stirring speed is preferably 60 rpm or higher, more preferably 65 rpm or higher, more preferably 80 rpm or higher, more preferably 100 rpm or higher, more preferably 120 rpm or higher, more preferably 150 rpm or higher, more preferably 170 rpm or higher, even more preferably 200 rpm or higher, and particularly preferably 220 rpm or higher. The upper limit of the stirring speed is not particularly limited, but is, for example, 1,000 rpm or lower. The term "stirring speed" refers to the rotation speed of the stirring blade.

[0130] In the coagulation step, the coagulation time is not particularly limited. When the coagulation step and the heat treatment step are performed discontinuously, the term "coagulation time" refers to the time from the start to the end of the coagulation step. For example, in the case of (i) coagulating the polymer particles by stirring a suspension containing polymer particles and a coagulant to obtain agglomerates of polymer particles, recovering the polymer particle agglomerates, and subjecting the recovered agglomerates to a subsequent heat treatment step, the term "coagulation time" refers to the time from the start of stirring the suspension containing polymer particles and a coagulant to the start of recovery of the polymer particle agglomerates. In the case of (ii) coagulating the polymer particles by stirring a suspension containing polymer particles and a coagulant to obtain agglomerates of polymer particles, stopping the stirring of the suspension, and subjecting the suspension or the agglomerates recovered from the suspension to a subsequent heat treatment step, the term "coagulation time" refers to the time from the start of stirring the suspension containing polymer particles and a coagulant to the stop of stirring the suspension. On the other hand, when the coagulation step and the heat treatment step are performed continuously in the same container (apparatus), the term "coagulation time" refers to the time from the start of the coagulation step to the start of the heat treatment step. For example, (iii) in the case where a suspension containing polymer particles and a coagulant is stirred to coagulate the polymer particles and obtain agglomerates of polymer particles, and then the suspension containing the agglomerates is stirred continuously while the subsequent heat treatment step is carried out using the suspension, the "coagulation time" means "the time from the start of stirring the suspension containing polymer particles and a coagulant to the start of the heat treatment step."

[0131] The coagulation time is, for example, preferably 0.1 seconds or more, more preferably 0.5 to 120.0 seconds, more preferably 1.0 to 60.0 seconds, even more preferably 2.0 to 40.0 seconds, and particularly preferably 2.0 to 20.0 seconds. When the coagulation time is 0.1 seconds or more, there is an advantage that the entire material can be coagulated sufficiently and uniformly. When the coagulation time is 120.0 seconds or less, there is an advantage that the production amount per unit time increases, that is, productivity improves.

[0132] (1-5. Heat treatment process) By heat-treating the polymer particle aggregates obtained in the coagulation step, denser aggregates can be formed, and aggregates that are less likely to contain impurities can be formed. As a result, there is an advantage that aggregates with excellent washability can be obtained. "Agglomerates with excellent washability" refers to "aggregates from which remaining impurities can be easily removed by washing," or in other words, "aggregates from which granules with a small amount of remaining impurities can be obtained using a small amount of washing water."

[0133] The heat treatment method in the heat treatment step is not particularly limited. Examples of the heat treatment method include a method of heating the polymer particle aggregates themselves, or a method of heating a suspension containing the polymer particle aggregates. As a method of heating a suspension containing the polymer particle aggregates, for example, the suspension may be heated by supplying water vapor into a container (apparatus).

[0134] The temperature of the suspension in the heat treatment step is referred to as the "heat treatment temperature" in this specification. The heat treatment temperature in the heat treatment step is preferably 60°C to 90°C, more preferably 65°C to 85°C, and even more preferably 70°C to 80°C. The higher the heat treatment temperature, the denser the aggregates can be formed, and the less likely it is that impurities will be encapsulated within the aggregates. As a result, there is an advantage that aggregates with superior washability can be obtained. On the other hand, the lower the heat treatment temperature, the smaller the median diameter of the resulting aggregates (secondary particles), and therefore there is an advantage that aggregates with excellent granulation properties can be obtained. "Agglomerates with excellent granulation properties" refers to "aggregates that can be easily formed into granules using a granulator," or in other words, "aggregates that can provide granules with a high bulk density by forming them into granules using a granulator." In other words, there is an advantage that the lower the heat treatment temperature, the greater the amount of granules with a high bulk density can be obtained. Furthermore, a lower heat treatment temperature has the advantage of minimizing the amount of energy used. Therefore, when the heat treatment temperature is within the above-mentioned range, it is possible to obtain granules with a small amount of residual impurities and a high bulk density with a small amount of energy. The heat treatment temperature in the heat treatment step may be (i) a value obtained by measuring the temperature of the suspension in real time during the heat treatment step, or (ii) when the set temperature of (i) the equipment, etc. and / or (ii) the temperature of the suspension during the heat treatment step are constant, the temperature of the suspension after the heat treatment step may be considered to be the heat treatment temperature.

[0135] In the heat treatment step, the time during which the aggregates are heat-treated is referred to as the "heat treatment time." The "heat treatment time" can also be interpreted as the "time during which the aggregates are exposed to a predetermined heat treatment temperature environment." The heat treatment time is not particularly limited, but is preferably 0.1 seconds or longer, more preferably 0.5 seconds to 15 minutes, more preferably 1.0 seconds to 120.0 seconds, even more preferably 1.0 seconds to 60.0 seconds, and particularly preferably 2.0 seconds to 20.0 seconds. A heat treatment time of 0.1 seconds or longer has the advantage that the entire aggregate can be heat-treated sufficiently and uniformly, resulting in aggregates with superior washability. A heat treatment time of 15 minutes or less has the advantage that energy consumption can be reduced, thereby minimizing the environmental impact and reducing production costs. The heat treatment step is preferably carried out until the aggregates achieve the desired particle size distribution, for example, until the median diameter of the aggregates reaches 1.0 μm to 200.0 μm.

[0136] It is preferable to stir the suspension during the heat treatment step as well. In other words, it is preferable to continue stirring the suspension from the start of the solidification step to the end of the heat treatment step.

[0137] The coagulation step and the heat treatment step may be carried out simultaneously. In the coagulation step, aggregates of polymer particles are gradually formed. By starting heating of the suspension simultaneously with the coagulation step, the gradually formed aggregates can be heat-treated.

[0138] Furthermore, a heat treatment step may be carried out after the coagulation step is completed. When a heat treatment step is carried out after the coagulation step is completed, the coagulation step and the heat treatment step may be carried out in the same container or in separate containers. For example, after the coagulation step is carried out using a container equipped with non-inclined stirring blades, the suspension containing the aggregates obtained in the coagulation step may be removed from the container in which the coagulation step was carried out and placed in a container other than the container in which the coagulation step was carried out, and then the heat treatment may be carried out.

[0139] The median diameter of the agglomerates obtained in the coagulation step can change depending on the heat treatment step. The median diameter of the agglomerates after the heat treatment step is not particularly limited. The larger the median diameter of the agglomerates after the heat treatment step, the better the washability of the agglomerates. In other words, the larger the median diameter of the agglomerates after the heat treatment step, the more advantageous it is that granules with a smaller amount of remaining impurities can be obtained. On the other hand, the smaller the median diameter after the heat treatment step, the better the granulation properties of the agglomerates. From these viewpoints, the median diameter of the agglomerates after the heat treatment step is preferably 1.0 μm to 200.0 μm, more preferably 1.0 μm to 150.0 μm, even more preferably 2.5 μm to 100.0 μm, and particularly preferably 10.0 μm to 50.0 μm.

[0140] (1-6. Recovery process) In this production method, after the heat treatment step, a recovery step may be carried out in which an aggregate containing polymer particles is recovered from the suspension. The recovery step can also be said to be a step of removing liquid components from the suspension after the heat treatment step. In this specification, the "aggregate of polymer particles obtained through the recovery step" may be referred to as a "dehydrated resin."

[0141] The method for recovering the aggregates containing polymer particles from the suspension is not particularly limited, and examples thereof include centrifugal dehydration, static separation, filtration dehydration, reduced pressure filtration dehydration, squeeze dehydration, and water evaporation. The apparatus used in each of the above methods can be appropriately selected according to the desired recovery method. For example, a filter press, 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.

[0142] (1-7. Cleaning process) In the washing step, the agglomerates after the heat treatment step are washed with a specific amount of washing water. When a recovery step is performed in this production method, the washing step may be a step of washing the agglomerates recovered in the recovery step after the heat treatment step with a specific amount of washing water. Because this production method includes a heat treatment step, it has the advantage of being able to obtain granules with a small amount of residual impurities even when the agglomerates are washed in the washing step with a smaller amount of washing water than conventionally.

[0143] The method for washing the aggregates (dehydrated resin) is not particularly limited, but examples thereof include (i) a method in which washing water is simply poured onto the aggregates (dehydrated resin), and (ii) a method in which the aggregates (dehydrated resin) are mixed with washing water and dehydrated, etc. The dehydration method is the same as the recovery method described above.

[0144] The washing water used in the washing step is not particularly limited, but examples thereof include pure water, distilled water, RO water, ion-exchanged water, and ultrapure water.

[0145] In the washing step, the temperature of the washing water is not particularly limited, but is preferably 10°C to 80°C, more preferably 30°C to 80°C, even more preferably 40°C to 80°C, and particularly preferably 50°C to 80°C. A higher washing water temperature has the advantage of higher impurity removal efficiency. A lower washing water temperature has the advantage of reduced energy consumption. Therefore, when the washing water temperature is within the above-mentioned range, there is the advantage of reduced energy consumption and high impurity removal efficiency.

[0146] In the washing step, washing water is used in an amount of 3000 parts by weight or less per 100 parts by weight of polymer particles contained in the aggregates. The amount of washing water used in the washing step is preferably 2000 parts by weight or less per 100 parts by weight of polymer particles contained in the aggregates, more preferably 1500 parts by weight or less, even more preferably 1000 parts by weight or less, even more preferably 750 parts by weight or less, and particularly preferably 500 parts by weight or less. When the amount of washing water used in the washing step is 3000 parts by weight or less, there is an advantage that the amount of wastewater can be reduced and the environmental load is reduced. The lower limit of the amount of washing water used is not particularly limited, but is, for example, 50 parts by weight or more.

[0147] When the method for washing the aggregates (dehydrated resin) involves mixing the aggregates (dehydrated resin) with washing water and dehydrating them, the time for mixing the aggregates (dehydrated resin) with washing water (washing time) is not particularly limited, but is preferably 1 to 20 minutes, more preferably 1 to 15 minutes, even more preferably 1 to 10 minutes, and particularly preferably 1 to 5 minutes. This configuration has the advantage of enabling treatment in a short time.

[0148] The number of times the aggregates are washed in the washing step is not particularly limited as long as it is at least one time, but is preferably 1 to 3 times, more preferably 1 to 2 times, and even more preferably 1 time. When washing is performed two or more times in the washing step, the "amount of washing water used" refers to the total amount of washing water used in all washings.

[0149] (1-8. Granulation process) In the granulation step, the aggregate (dehydrated resin) obtained in the recovery step is formed into granules using a granulator.

[0150] The granulator is not particularly limited, but is preferably, for example, an extrusion granulator (extrusion granulator). A granulator (extrusion granulator) is equipped with, for example, a raw material supply section (sometimes called a "hopper") that supplies the wet resin as a raw material, a screw, and a die having one or more discharge holes. An extrusion granulator equipped with a screw is also called a screw-type extrusion granulator. In addition to screw-type extrusion granulators, examples of extrusion granulators (extrusion granulators) include roll-type extrusion granulators, basket-type extrusion granulators, and piston-type extrusion granulators.

[0151] The agglomerates are extruded in the form of threads or strings from a die provided in the granulator. In this specification, the agglomerates extruded from the die may be referred to as "strands." In other words, the agglomerates are extruded in the form of strands from the die.

[0152] The strands can be cut with a crushing blade to obtain granules. The type of crushing blade and the cutting method are not particularly limited.

[0153] (drying process) The method may include a step of drying the resulting granules.

[0154] By carrying out the drying step, it is possible to remove the water contained in the granules and also to promote fusion between the polymer particles in the granules.

[0155] In the drying step, the method for drying the granules is not particularly limited, and any known method can be used. For example, the granules may be dried by heat treatment.

[0156] When the granules are dried by heat treatment, the temperature for the heat treatment of the granules is not particularly limited, but is preferably, for example, 40° C. to 200° C., more preferably 60° C. to 200° C., more preferably 60° C. to 180° C., and even more preferably 60° C. to 150° C. The time for the heat treatment of the granules 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.

[0157] [2. Granules] The granules obtained by the granule production method according to one embodiment of the present invention (hereinafter also referred to as "the present granules") have the advantage of a high bulk density. The high bulk density of the granules allows the granules to be packed densely into transport tanks and bags, which is expected to reduce transportation costs. The present granules can be further washed to produce granules with a low content of impurities (e.g., Cl content). Alternatively, when the present production method includes a washing step, the granules obtained by this production method have the advantage of a low content of impurities. The low content of impurities has the advantage that molded articles or cured products of resin compositions containing the granules have excellent qualities such as color tone, tensile strength, impact resistance, dispersibility, and compatibility. In this specification, "granules (granules of polymer particles)" may refer to aggregates of primary polymer particles, in other words, secondary polymer particles.

[0158] The diameter of the present granules is not particularly limited, but is preferably 0.2 mm to 10.0 mm, more preferably 0.5 mm to 8.0 mm, even more preferably 1.0 mm to 5.0 mm, and particularly preferably 2.0 mm to 4.0 mm.

[0159] The length of the present granules is not particularly limited, but is preferably 0.2 mm to 20.0 mm, more preferably 0.5 mm to 15.0 mm, even more preferably 1.0 mm to 10.0 mm, and particularly preferably 2.0 mm to 8.0 mm.

[0160] The shape of the present granules is not particularly limited, but is preferably one or more selected from the group consisting of cylindrical, prismatic and spherical.

[0161] As described above, the granules can be used as a modifier by mixing them with any resin (matrix resin), such as a thermoplastic resin. The matrix resin may be used in the form of granules (pellets). Therefore, when one or more selected from the group consisting of (i) granule diameter, (ii) granule length, and (iii) granule shape are within the above-described ranges, the diameter, length, and shape of the matrix resin mixed with the granules are similar to those of the granules, resulting in more uniform mixing of the granules with the matrix resin. Furthermore, when one or more selected from the group consisting of (i) granule diameter, (ii) granule length, and (iii) granule shape are within the above-described ranges, the following advantages are achieved: (i) the granules can be smoothly fed into a mixing device, and (ii) they are easy to handle.

[0162] The bulk density of this granule is 0.330 g / cm 3 It is preferable that the concentration is 0.340 g / cm or more. 3 More preferably, it is 0.350 g / cm or more. 3 More preferably, it is 0.360 g / cm or more. 3 More preferably, it is 0.370 g / cm or more. 3 More preferably, it is 0.380 g / cm or more. 3 More preferably, it is 0.390 g / cm or more. 3 More preferably, it is 0.400 g / cm or more. 3 It is particularly preferable that the bulk density of the granules is 0.350 g / cm or more. The higher the bulk density of the granules, the more densely the polymer particles are aggregated in the granules. 3 Granules having a bulk density of 1.000 g / cm or more can be said to have a sufficiently high bulk density. The upper limit of the bulk density of the granules is not particularly limited, but it can be, for example, 1.000 g / cm. 3 The method for measuring the bulk density of granules will be described in detail in the Examples below.

[0163] The amount of chlorine (Cl) in the present granules is preferably 380 ppm or less, more preferably 350 ppm or less, more preferably 330 ppm or less, more preferably 300 ppm or less, more preferably 280 ppm or less, more preferably 250 ppm or less, more preferably 230 ppm or less, more preferably 200 ppm or less, more preferably 180 ppm or less, more preferably 150 ppm or less, even more preferably 130 ppm or less, and particularly preferably 100 ppm or less, based on the mass of the granules. [Example]

[0164] 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.

[0165] [Evaluation method] The methods for evaluating the aggregates and granules obtained in the examples and comparative examples are described below.

[0166] <Measurement of volume average particle size> The volume average particle diameter (Mv) of the polymer particles dispersed in the latex was measured using a Nanotrac Wave II-EX150 (manufactured by Microtrackbell Co., Ltd.). The measurement sample was prepared by diluting the latex with deionized water. The measurement was performed by inputting the refractive index of water and the polymer particles obtained in the production example, measuring for 120 seconds, and adjusting the sample concentration so that the loading index was within the range of 1 to 10.

[0167] <Measurement of aggregate particle size distribution and median diameter based on volume cumulative frequency> The suspensions of aggregates obtained in the Examples and Comparative Examples (dispersions containing aggregates recovered in the recovery step) were subjected to a laser diffraction / scattering particle size distribution analyzer LA-950 (manufactured by Horiba, Ltd.) to measure the particle size distribution of the aggregates in the suspensions, and the particle size distribution was obtained from the volume cumulative frequency % of aggregates with a volume average particle size of 0.01 μm to 3 mm. The particle size (D50) at which the volume cumulative frequency was 50% in the particle size distribution was taken as the median diameter (μm) of the aggregates.

[0168] <Measurement of bulk specific gravity of granules> The bulk density of the obtained granules was measured using a bulk density measuring device (JIS K-6720 type manufactured by Kuramochi Scientific Instruments Manufacturing Co., Ltd.) in accordance with JIS-K-6720:1999.

[0169] <Amount of residual impurities in granules> The amount of Cl derived from the coagulant as a residual impurity in the obtained granules was measured using a fluorescent X-ray analyzer JSX-1000S (manufactured by JEOL Ltd.).

[0170] [Production Example 1] <Latex manufacturing> (Polymerization of the first elastic body) A mixture of the following composition was charged into a glass reactor: Mixture composition: (parts by weight) Ion-exchanged water 220 Boric acid 0.3 Sodium carbonate 0.03 Sodium N-lauroyl sarcosinate 0.09 Sodium formaldehyde sulfoxylate 0.09 Disodium ethylenediaminetetraacetic acid 0.006 Ferrous sulfate heptahydrate 0.002.

[0171] Next, the air in the glass reactor was replaced with nitrogen. Subsequently, the raw materials charged into the glass reactor were stirred in a nitrogen stream while the temperature inside the glass reactor was raised to 80°C. Then, a mixed solution was prepared containing a first monomer mixture consisting of 25 parts by weight of methyl methacrylate (MMA) and 0.1 parts by weight of allyl methacrylate (AMA), 0.1 parts by weight of t-dodecyl mercaptan as a chain transfer agent, and 0.1 parts by weight of t-butyl hydroperoxide (BHPO) as a polymerization initiator. Next, 25% by weight of the prepared mixed solution (100% by weight) was charged into the glass reactor all at once, and polymerization was carried out for 45 minutes.

[0172] Subsequently, the remaining 75% by weight of the mixture was continuously added to the glass reactor over 1 hour. After the continuous addition, the temperature in the glass reactor was maintained at 80°C for another 2 hours to complete the polymerization, thereby obtaining a latex of an elastomer (a first elastomer, an elastomer composed only of methyl methacrylate, which can also be said to be the innermost layer elastomer). During the temperature maintenance (2 hours at 80°C) after the addition of the mixture, 0.2 parts by weight of sodium N-lauroyl sarcosinate was added to the glass reactor. The average particle size of the obtained first elastomer was 0.16 μm, and the polymerization conversion rate (amount of polymerized product / amount of monomer charged) was 98%.

[0173] (Polymerization of the second elastic body) The glass reactor used in the polymerization of the first elastomer was used in the polymerization of the second elastomer. First, the glass reactor containing the latex of the first elastomer was maintained at 80°C under a nitrogen stream. After adding 0.1 parts by weight of potassium persulfate to the latex, a second monomer mixture consisting of 41 parts by weight of n-butyl acrylate (BA), 9 parts by weight of styrene (St), and 1 part by weight of AMA was continuously added over a period of 5 hours. During the continuous addition of the second monomer mixture, potassium oleate was added to the latex in three portions, totaling 0.1 parts by weight. After the continuous addition of the second monomer mixture was completed, an additional 0.05 parts by weight of potassium persulfate was added to the reaction system to complete the polymerization. The temperature inside the glass reactor was maintained at 80°C for an additional 2 hours. By this operation, a latex containing an elastomer (a multi-stage polymerized elastomer composed only of (meth)acrylate rubber) was obtained, which was obtained by multi-stage polymerization of the first elastomer and the second elastomer (an elastomer composed only of butyl acrylate) in this order. The volume average particle size of the obtained elastomer was 0.23 μm, and the polymerization conversion rate was 99%.

[0174] (Polymerization of grafted portion) The glass reactor used in the polymerization of the second elastomer described above was used directly for the polymerization of the graft portion. First, the temperature inside the glass reactor containing the elastomer latex was maintained at 80°C. After 0.02 parts by weight of potassium persulfate was added to the latex, a mixture of a graft monomer mixture consisting of 24 parts by weight of MMA and 1 part by weight of n-BA and 0.1 parts by weight of t-dodecyl mercaptan was continuously added over 1 hour. After the addition of the mixture was completed, the temperature inside the glass reactor was maintained at 80°C for another 1 hour. This procedure yielded a latex (aqueous latex) containing a rubber-containing graft copolymer (polymer particles) having an elastomer and a graft portion grafted to the elastomer. The volume average particle diameter of the resulting polymer particles was 0.25 μm, and the polymerization conversion rate was 99%.

[0175] Example 1 <Production of agglomerates and granules> The apparatus (vessel) used was a cylindrical vessel with an inner diameter of 55 mm and a vertical length of 400 mm. The vessel contained two non-inclined / inclined impellers: one impeller with a 0-degree inclination angle and three impellers with a 45-degree inclination angle, attached 180 degrees apart to a 20 mm diameter stirring shaft. In the non-inclined / inclined impellers, the impeller with a 0-degree inclination angle is referred to as the H-impeller, and the impeller with a 45-degree inclination angle is referred to as the inclined paddle impeller. In other words, the non-inclined / inclined impeller is both an H-impeller and an inclined paddle impeller. The center of the stirring shaft of the non-inclined / inclined impeller was the same as the central axis of the vessel. Furthermore, in the non-inclined / inclined impellers, the H-impeller had a blade diameter of 48 mm and a blade height of 42 mm, while each inclined paddle impeller had a blade diameter of 48 mm and a blade height of 14 mm. Two non-inclined-inclined impellers were installed in series in the vertical direction, with the H-blade (or inclined paddle blade) of each of the two non-inclined-inclined impellers positioned 180 degrees apart horizontally.

[0176] (solidification process) While stirring at 250 rpm, (i) a 50°C aqueous latex (polymer particle concentration in 100 wt% aqueous latex was 30 wt%) was fed at a rate of 1500 mL / min from a position 0 mm vertically above the bottom of the apparatus, and (ii) a 50°C aqueous calcium chloride solution (calcium chloride concentration in 100 wt% aqueous coagulant solution was 25 wt%) was fed at a rate of 27 mL / min from a position 10 mm vertically above the bottom of the apparatus. The coagulation step was carried out by stirring the suspension containing polymer particles and coagulant. Because the temperatures of the aqueous latex containing polymer particles and the aqueous coagulant solution used in the coagulation step were both 50°C, the temperature during the coagulation step was considered to be 50°C. Furthermore, during the coagulation step, the concentration of polymer particles in the 100 wt% suspension containing polymer particles and coagulant was 30 wt%. The amount of coagulant used in the coagulation step was 1.5 parts by weight per 100 parts by weight of polymer particles. The solidification process took 11 seconds.

[0177] (Heat treatment process) Next, steam was supplied from a position 250 mm vertically from the bottom of the apparatus, and a heat treatment step was carried out. The suspension after the heat treatment step was recovered from an outlet at the top of the apparatus. The concentration of polymer particles in 100% by weight of the recovered suspension was 29% by weight. In other words, the concentration of polymer particles in 100% by weight of the suspension in the heat treatment step was 29% by weight. Depending on the amount of steam used in the heat treatment step, the concentration of polymer particles in the heat treatment step decreased from the concentration of polymer particles in the coagulation step. The duration of the heat treatment step was 10 seconds.

[0178] Here, prior to carrying out the Examples and Comparative Examples, the heat treatment temperature inside the apparatus was confirmed. Specifically, the same apparatus as that used in each Example and Comparative Example was used, and only water was supplied from a position 0 mm vertically from the bottom of the apparatus, and the heat treatment process was carried out under the same conditions as in each Example and Comparative Example. When the temperature of the water inside the apparatus was measured from the time the heat treatment process was carried out (i.e., steam was supplied) to the outlet of the apparatus, the water temperature was found to be constant. Since the majority of the suspension is water, it can be said that the heat conduction efficiency of the water and the suspension is roughly the same. Therefore, in the Examples and Comparative Examples, the temperature of the suspension recovered from the outlet at the top of the apparatus can be considered to be the heat treatment temperature.

[0179] In Example 1, the temperature of the recovered suspension was measured and found to be 70°C, so the heat treatment temperature in Example 1 can be considered to have been 70°C.

[0180] (Recovery process) Next, the suspension recovered after the heat treatment step was filtered and dehydrated under reduced pressure to obtain an aggregate (dehydrated resin) from the suspension.

[0181] (Cleaning process) Next, the aggregates (dehydrated resin) obtained in the recovery step were washed once by pouring washing water at 70°C from above the aggregates in an amount six times the weight of the polymer particles in the aggregates.

[0182] (granulation process) Next, the agglomerates after the washing process were fed into a granulator equipped with a die, and the agglomerates were formed into granules at room temperature. An extrusion compression granulator equipped with a twin screw was used as the granulator. The die equipped in the granulator had a plate thickness of 10 mm and 32 discharge holes. The diameter of each discharge hole in the die was Φ5 mm, and the spacing (pitch) between each discharge hole was 9 mm.

[0183] (drying process) After the granulation step, the obtained granules were left (left stationary) in a dryer at 150°C for 2 hours to dry.

[0184] The bulk density and Cl content of the dried granules were measured using the methods described above. The results are shown in Table 1.

[0185] Example 2 (solidification process) The solidification step was carried out in the same manner as in Example 1.

[0186] (Heat treatment process) The heat treatment step was carried out in the same manner as in Example 1, except that the amount of steam used was changed. The concentration of polymer particles in 100% by weight of the recovered suspension was 28% by weight. That is, the concentration of polymer particles in 100% by weight of the suspension in the heat treatment step was 28% by weight. The heat treatment step lasted for 10 seconds. Furthermore, the temperature of the recovered suspension was measured and found to be 80°C, so the heat treatment temperature in Example 2 can be considered to have been 80°C.

[0187] Subsequently, the recovery, washing, granulation, and drying processes were carried out in the same manner as in Example 1 to obtain dried granules. The bulk density and Cl content of the dried granules were measured using the methods described above. The results are shown in Table 1.

[0188] Example 3 (Solidification process and heat treatment process) Pure water was supplied from a position 150 mm from the bottom of the apparatus, and the concentration of the polymer particles was adjusted to 15 wt % in 100 wt % of the suspension obtained in the coagulation step. Except for this operation, the coagulation step and heat treatment step were carried out in the same manner as in Example 2. That is, in Example 3, the concentration of polymer particles in 100 wt % of the suspension in the heat treatment step was 15 wt %. Furthermore, in Example 3, the supply of pure water increased the flow rate of the suspension in the apparatus, thereby shortening the times of the coagulation step and the heat treatment step. Specifically, in Example 3, the time for the coagulation step was 8 seconds, and the time for the heat treatment step was 5 seconds. The temperature of the recovered suspension was measured and found to be 80°C, so the heat treatment temperature in Example 3 can be considered to be 80°C.

[0189] Subsequently, the recovery, washing, granulation, and drying processes were carried out in the same manner as in Example 1 to obtain dried granules. The bulk density and Cl content of the dried granules were measured using the methods described above. The results are shown in Table 1.

[0190] (Comparative Example 1) (solidification process) The solidification step was carried out in the same manner as in Example 1.

[0191] (Heat treatment process) The heat treatment step was carried out in the same manner as in Example 1, except that the amount of steam used was changed. The concentration of polymer particles in 100% by weight of the recovered suspension was 27% by weight. That is, the concentration of polymer particles in 100% by weight of the suspension in the heat treatment step was 27% by weight. The heat treatment step lasted for 10 seconds. Furthermore, the temperature of the recovered suspension was measured and found to be 95°C, so the heat treatment temperature in Comparative Example 1 can be considered to have been 95°C.

[0192] Subsequently, the recovery, washing, granulation, and drying processes were carried out in the same manner as in Example 1 to obtain dried granules. The bulk density and Cl content of the dried granules were measured using the methods described above. The results are shown in Table 1.

[0193] (Comparative Example 2) The same method as in Example 1 was used to supply the aqueous latex and the coagulant solution to the apparatus and carry out the coagulation process, but steam was not supplied, i.e., the heat treatment process was not carried out. The agglomerates after the coagulation process were collected from the outlet at the top of the apparatus. In Comparative Example 2, the coagulation process lasted for 21 seconds.

[0194] Subsequently, the recovery, washing, granulation, and drying processes were carried out in the same manner as in Example 1 to obtain dried granules. The bulk density and Cl content of the dried granules were measured using the methods described above. The results are shown in Table 1.

[0195] (Comparative Example 3) (Solidification process and heat treatment process) Except for changing the amount of steam used, the coagulation step and the heat treatment step were carried out in the same manner as in Example 3. The time for the heat treatment step was 5 seconds, the same as in Example 3. Furthermore, the temperature of the recovered suspension was measured and found to be 95°C, so the heat treatment temperature in Comparative Example 3 can be considered to have been 95°C.

[0196] Subsequently, the recovery, washing, granulation, and drying processes were carried out in the same manner as in Example 1 to obtain dried granules. The bulk density and Cl content of the dried granules were measured using the methods described above. The results are shown in Table 1.

[0197] [Table 1] [Industrial Applicability]

[0198] According to one embodiment of the present invention, a method for producing granules can be provided that can produce granules with a low amount of residual impurities and a high bulk density. As a result, according to one embodiment of the present invention, granules with a low amount of residual impurities and a high bulk density can be provided. The granules obtained by the production method according to one embodiment of the present invention can be suitably used as a modifier to impart desired physical properties to a resin composition containing the granules and an arbitrary resin, or to a molded or cured product obtained from the resin composition. Therefore, one embodiment of the present invention can be suitably used as a 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 molding 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. [Explanation of symbols]

[0199] 1. Mixing blade 10. Agitator shaft 100 ··· Mixing blade

Claims

1. a coagulation step of coagulating the polymer particles by stirring a suspension containing the polymer particles and a coagulant to obtain an aggregate of the polymer particles; a heat treatment step of heat treating the aggregate obtained in the solidification step; a washing step of washing the aggregate after the heat treatment step; a granulation step of forming the agglomerate after the washing step into granules using a granulator; and In the heat treatment step, the heat treatment temperature is 60°C to 90°C, In the washing step, the agglomerates are washed using washing water in an amount of 3,000 parts by weight or less relative to 100 parts by weight of the polymer particles contained in the agglomerates.

2. The method for producing granules according to claim 1, wherein the median diameter of the agglomerates after the heat treatment step is 1.0 μm to 200.0 μm.

3. The method for producing granules according to claim 1 or 2, wherein the shape of the granules is one or more selected from the group consisting of cylindrical, prismatic and spherical.

4. The method for producing granules according to claim 1 or 2, wherein the diameter of the granules is 0.5 mm to 5.0 mm and the length of the granules is 0.5 mm to 20.0 mm.

5. The bulk density of the granules is 0.350 g / cm ３ The method for producing granules according to claim 1 or 2, wherein the method is as described above.

6. 3. The method for producing granules according to claim 1, wherein the polymer particles are a rubber-containing graft copolymer having an elastomer and a graft portion graft-bonded to the elastomer.

7. The method for producing granules according to claim 6, wherein the graft portion comprises one or more structural units selected from the group consisting of an aromatic vinyl unit, a vinylcyan unit, and a (meth)acrylate unit.

8. The method for producing granules according to claim 6, wherein the elastic body is composed only of a (meth)acrylate rubber.

9. The method for producing granules according to claim 1 or 2, wherein the coagulant is a divalent or higher valent salt.

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