JP2010222499A - Dispersion containing (meth)acrylic resin particle and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion of (meth)acrylic resin particles having a narrow particle size distribution width, and to provide a method for producing the same. <P>SOLUTION: The dispersion is constituted of a dispersion phase formed of (meth)acrylic resin particles and a matrix phase formed of a water-soluble aid, and contains a nonionic surfactant (for example, a fatty acid ester of a polyhydric alcohol having an HLB of 1-10). The (meth)acrylic resin particles may be constituted of a homopolymer or a copolymer of a (meth)acrylic acid alkyl ester, and the variation coefficient of the average particle diameter may be 30 or less. The dispersion is produced by melting and kneading a (meth)acrylic resin and the water-soluble aid in the presence of the nonionic surfactant. The variation coefficient of the average particle diameter of the (meth)acrylic resin particles can be reduced by using the kneading time as an indicator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dispersion containing (meth) acrylic resin particles having a narrow particle size distribution width, a method for producing the dispersion, a method for producing (meth) acrylic resin particles from the dispersion, and (meth) acrylic resin particles. The present invention relates to a method for reducing the coefficient of variation in average particle diameter.

  Conventionally, as a method for producing spherical resin particles, in a dispersion composed of a dispersed phase formed of resin particles and a matrix phase, a method in which only the matrix phase is dissolved and removed with a solvent is used. .

  Japanese Patent Application Laid-Open No. 2007-2223 (Patent Document 1) discloses an organic solid whose surface is modified by removing the matrix component from a dispersion composed of an organic solid component, a matrix component, and a modifier. A method of obtaining particles is disclosed. This document discloses a combination of a thermoplastic resin such as a (meth) acrylic resin as an organic solid component and a matrix component containing at least an oligosaccharide. Moreover, nonionic surfactant is illustrated as an antistatic agent. The coefficient of variation of the average particle size of the obtained organic solid particles may be 50 or less, and it is described that the particle size distribution width can be narrowed by adjusting the kneading conditions. Furthermore, it is described in the Example of this literature that the styrene butadiene copolymer particle | grains which provided the antistatic property using the nonionic surfactant were obtained.

  However, in this document, the nonionic surfactant is described as an antistatic agent, and is not described as an additive for controlling the size of the (meth) acrylic resin particles. Therefore, (meth) acrylic resin particles having a narrow particle size distribution width cannot be easily produced.

  Even in the dispersion of resin particles having different sizes, the particle size distribution width can be narrowed by classifying the generated resin particles, but the operation is complicated and the productivity is low. Further, since a large amount of resin particles having a size that cannot be used by classification is generated, it is economically disadvantageous.

JP 2007-2223 A (Claim 1, paragraphs [0041] [0068] [0070] [0090] [0154] [0157], Examples)

  Accordingly, an object of the present invention is to provide a dispersion of (meth) acrylic resin particles having a narrow particle size distribution width and a method for producing the same.

  Another object of the present invention is to provide a method for industrially stably producing (meth) acrylic resin particles having a narrow particle size distribution width.

  Still another object of the present invention is to provide a method of reducing the variation coefficient of the average particle diameter of (meth) acrylic resin particles and narrowing the particle size distribution width.

  As a result of intensive studies to achieve the above-mentioned problems, the inventors of the present invention have found that when (meth) acrylic resin and a water-soluble auxiliary are melt-kneaded in the presence of a nonionic surfactant, (meth) acrylic resin particles The present invention was completed by finding that a dispersion containing (meth) acrylic resin particles having a narrow particle size distribution width can be produced industrially and stably without increasing the average particle size and corresponding to the kneading time. did.

  That is, the dispersion of the present invention is a dispersion composed of a dispersed phase formed of (meth) acrylic resin particles and a matrix phase formed of a water-soluble auxiliary agent, and includes a nonionic surfactant.

  The (meth) acrylic resin particles may be particles that exhibit an increasing behavior after the average particle diameter is reduced with the lapse of the kneading time in the melt-kneading with the water-soluble auxiliary agent. The variation coefficient of the average particle diameter of the (meth) acrylic resin particles may be 30 or less (particularly about 10 to 30). Further, the (meth) acrylic resin constituting the particles may be a homopolymer or a copolymer of (meth) acrylic acid alkyl ester.

  The nonionic surfactant may be a fatty acid ester of a polyhydric alcohol. The hydrophilic-lipophilic balance (HLB) of the fatty acid ester of the polyhydric alcohol may be about 1 to 10 (particularly 1 to 5). The nonionic surfactant may be composed of at least one component selected from (poly) glycerin fatty acid ester, sorbitan fatty acid ester, and sucrose fatty acid ester.

  The ratio (weight ratio) between the (meth) acrylic resin particles and the nonionic surfactant may be about the former / the latter = 99.9 / 0.1 to 50/50. Further, the ratio (weight ratio) between the (meth) acrylic resin particles and the water-soluble auxiliary agent may be about the former / the latter = 10/90 to 60/40.

  In the present invention, a (meth) acrylic resin and a water-soluble auxiliary are melt-kneaded in the presence of a nonionic surfactant to form a dispersed phase formed of (meth) acrylic resin particles and a water-soluble auxiliary. For producing a dispersion composed of a structured matrix phase. Moreover, the method of manufacturing a (meth) acrylic-type resin particle by removing a matrix phase from the dispersion of this invention is included.

  The present invention includes a method for reducing the coefficient of variation of the average particle diameter of (meth) acrylic resin particles by melt-kneading a (meth) acrylic resin and a water-soluble auxiliary agent in the presence of a nonionic surfactant. .

  In this specification, acrylic acid and methacrylic acid are collectively referred to as (meth) acrylic acid, acrylate and methacrylate are collectively referred to as (meth) acrylate, and acrylic monomers and methacrylic monomers are referred to as ( It is generically called a (meth) acrylic monomer. Further, alkylene glycol and polyalkylene glycol are collectively referred to as (poly) alkylene glycol, and glycerin and polyglycerin are collectively referred to as (poly) glycerin.

  In the present invention, a (meth) acryl having a narrow particle size distribution width is obtained by melt-kneading a (meth) acrylic resin and a water-soluble auxiliary agent in the presence of a nonionic surfactant (for example, a fatty acid ester of a polyhydric alcohol). A dispersion containing resin particles can be produced industrially stably. Therefore, (meth) acrylic resin particles having a narrow particle size distribution width can be industrially efficiently obtained without classifying the particles. Moreover, the average particle diameter of the resin particles can be adjusted in accordance with the kneading time. Furthermore, the coefficient of variation of the average particle diameter of the dispersed phase particles can be easily reduced by melt-kneading the (meth) acrylic resin and the water-soluble auxiliary agent in the presence of nonionic surface activity.

[Dispersion]
The dispersion of the present invention is a dispersion composed of a dispersed phase formed of (meth) acrylic resin particles and a matrix phase formed of a water-soluble auxiliary agent, and includes a nonionic surfactant.

((Meth) acrylic resin particles)
The (meth) acrylic resin constituting the (meth) acrylic resin particles is a homopolymer or copolymer of a (meth) acrylic monomer, a (meth) acrylic monomer and a copolymerizable monomer. A copolymer may also be used.

As the (meth) acrylic monomer, (meth) acrylic acid alkyl ester [for example, methyl (meth) acrylate, ethyl (meth) acrylate, n- or i-propyl (meth) acrylate, n-, i-, C _1-20 alkyl (meth) acrylates such as s- or t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate], (Meth) acrylic acid cycloalkyl ester [e.g., C _3-12 cycloalkyl (meth) acrylate such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, etc .; decalinyl (meth) acrylate, norbornyl (meth) acrylate, bornyl (meth A) Relate, and di or tetra C _3-8 cycloalkyl (meth) acrylates such as adamantyl (meth) acrylate, (meth) acrylic acid aryl ester [e.g., phenyl (meth) acrylate, etc.]; (meth) acrylic acid hydroxyalkyl Esters [for example, hydroxy C _2-10 alkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc.], (meth) acrylic acid alkoxyalkyl esters [for example, a _{2-C 1-5} alkoxy _{C 1-10} alkyl (meth) acrylates such as methoxyethyl (meth) acrylate, (meth) acrylic acid haloalkyl esters [e.g., 2,2,2 triflic Roechiru (meth) halo C _1-10 alkyl (meth) acrylates such as acrylates, epoxy group-containing (meth) acrylates [for example, glycidyl (meth) acrylate], a cyano group-containing (meth) acrylic monomers [ For example, (meth) acrylonitrile etc.], (meth) acrylic acid, (meth) acrylamides, such as N-methyl (meth) acrylamide, etc. can be illustrated. These (meth) acrylic monomers can be used alone or in combination of two or more. Among these (meth) acrylic monomers, from the viewpoint of having a highly hydrophobic substituent, (meth) acrylic acid alkyl ester, (meth) acrylic acid cycloalkyl ester, and (meth) acrylic acid aryl ester are Particularly preferred are (meth) acrylic acid alkyl esters (for example, C _1-5 alkyl methacrylate, especially C _1-3 alkyl methacrylate such as methyl methacrylate).

  Examples of copolymerizable monomers with (meth) acrylic monomers include styrenes (eg, styrene, p-chlorostyrene, α-methylstyrene, sodium styrenesulfonate), olefins (eg, ethylene, Propylene, 1-butene, isobutene, etc.), organic acid vinyl esters (for example, vinyl acetate, vinyl propionate, vinyl crotonic acid, vinyl benzoate, etc.). These copolymerizable monomers can be used alone or in combination of two or more.

  The ratio (weight ratio) between the (meth) acrylic monomer and the copolymerizable monomer is, for example, the former / the latter = 100/0 to 50/50 (for example, 99.5 / 0.5 to 50 / 50), preferably 100/0 to 70/30 (for example, 99/1 to 70/30), more preferably about 100/0 to 80/20.

  Among these (meth) acrylic resins, in particular, a (meth) acrylic acid alkyl ester homopolymer or copolymer ((meth) acrylic acid alkyl ester heavy polymer) containing (meth) acrylic acid alkyl ester as an essential polymerization component. Coalescence) is preferred.

Representative (meth) acrylic acid alkyl ester polymers include (meth) acrylic acid alkyl esters such as poly C _1-5 alkyl methacrylate (for example, poly C _1-3 alkyl methacrylate such as polymethyl methacrylate). Copolymer; methyl methacrylate-C _2-5 alkyl methacrylate copolymer, methyl methacrylate-C _1-5 alkyl acrylate copolymer, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate-acrylic acid ester- (meth) Examples include (meth) acrylic acid alkyl ester copolymers such as acrylic acid copolymer, methyl methacrylate-ethylene copolymer, methyl methacrylate-styrene copolymer, and methyl methacrylate-vinyl acetate copolymer. Among these (meth) acrylic acid alkyl ester polymers, methyl methacrylate homopolymer or copolymer (for example, polymethyl methacrylate, methyl methacrylate-C _2-5 alkyl methacrylate copolymer), which contains methyl methacrylate as an essential polymerization component, in particular. Polymers etc.) are preferred.

  The weight average molecular weight of the (meth) acrylic resin may be, for example, 10,000 to 1,000,000, preferably 50,000 to 500,000, more preferably about 10,000 to 300,000. .

  Although it does not restrict | limit especially about the glass transition temperature (Tg) of (meth) acrylic-type resin, From a handleability viewpoint, it is 10-140 degreeC, Preferably it is 30-130 degreeC, More preferably, it is about 50-120 degreeC. Good.

  The number average particle diameter (Dn) of the (meth) acrylic resin particles may be, for example, about 0.5 to 10 μm, 1 to 5 μm, or 1.5 to 3 μm. The volume average particle diameter (Dw) may be, for example, about 0.5 to 10 μm, 1 to 5 μm, or about 2 to 5 μm.

  The ratio Dw / Dn of the volume average particle diameter Dw [μm] to the number average particle diameter Dn [μm] of the (meth) acrylic resin particles is 1 to 2, preferably 1.05 to 1.5, and more preferably 1. It may be about .1 to 1.25 (particularly 1.1 to 1.2).

  The number average particle diameter Dn and the volume average particle diameter Dw are measured by a conventional method.

  As an index of the particle size distribution width, the coefficient of variation (CV) of the average particle diameter is used, but the coefficient of variation (%) of the average particle diameter of the (meth) acrylic resin particles ([standard deviation of the number average particle diameter / Number average particle diameter] × 100) may be 30 or less (for example, about 0.1 to 30, preferably about 1 to 29, and more preferably about 2 to 28).

  The (meth) acrylic resin particles may be particles that exhibit an increasing behavior after the average particle diameter is reduced with the lapse of the kneading time in the melt-kneading with the water-soluble auxiliary agent. Further, as the kneading time elapses, the variation coefficient of the average particle diameter of the (meth) acrylic resin particles may be repeatedly reduced and increased. In the present invention, by adding a nonionic surfactant to both the (meth) acrylic resin and the water-soluble auxiliary agent, the average particle diameter of the (meth) acrylic resin particles is adjusted according to the kneading time. In addition, the coefficient of variation of the average particle diameter can be reduced.

  The shape of the (meth) acrylic resin particles (corresponding to the shape of the particles obtained after removing the matrix phase) is, for example, spherical, elliptical, polygonal, prismatic, cylindrical, rod-shaped, etc. Usually, it is spherical. The spherical shape is not limited to a true spherical shape, and includes, for example, a shape in which the length ratio between the major axis and the minor axis is, for example, major axis / minor axis = about 1.5 / 1 to 1/1. The ratio of the length of the major axis to the minor axis is preferably major axis / minor axis = 1.3 / 1 to 1/1 (for example, 1.2 / 1 to 1/1), more preferably 1.1 / 1 to 1. It may be about 1/1.

(Water-soluble auxiliary agent)
The water-soluble auxiliary agent is not particularly limited as long as it is water-soluble and can be melt-molded, and examples thereof include water-soluble synthetic polymers such as polyvinyl alcohol polymers, polyethylene glycols and polyethylene oxides; Can be mentioned. Of these water-soluble auxiliaries, water-soluble saccharides are preferable from the viewpoint that the melt viscosity can be easily adjusted, the spherical resin particles can be stably produced, and the burden on the environment can be reduced. The water-soluble saccharide (a) was selected from the oligosaccharide (a-1) and the water-soluble polysaccharide (a-2) having at least one cyclic structure, depending on the meltability of the (meth) acrylic resin. At least one kind of saccharide is preferably used, and both may be used in combination. When the water-soluble auxiliary is composed of the water-soluble saccharide (a), it may usually further contain a water-soluble plasticizing component (b).

(A) Water-soluble saccharides (a-1) Oligosaccharides Oligosaccharides are roughly classified into homooligosaccharides and heterooligosaccharides. These oligosaccharides may be anhydrides. In the oligosaccharide, a monosaccharide and a sugar alcohol may be bonded. The oligosaccharide may be an oligosaccharide composition composed of a plurality of sugar components. Even such an oligosaccharide composition may be simply referred to as an oligosaccharide. Oligosaccharides (or oligosaccharide compositions) can be used alone or in combination of two or more.

  Oligosaccharides include disaccharides to decasaccharides. Examples of the disaccharide include homo-oligosaccharides such as trehalose and maltose; and hetero-oligosaccharides such as lactose and sucrose. Trisaccharides include homo-oligosaccharides such as maltotriose; hetero-oligosaccharides such as manninotriose. Examples of tetrasaccharides include homo-oligosaccharides such as maltotetraose; and hetero-oligosaccharides such as tetraose in which sugar or sugar alcohol is bonded to the reducing end such as panose. Examples of pentasaccharides include homo-oligosaccharides such as maltopentaose; and hetero-oligosaccharides such as pentaose in which a disaccharide is bonded to the reducing end of panose. Examples of the hexasaccharide include homooligosaccharides such as maltohexaose.

  The oligosaccharide may be an oligosaccharide composition produced by degradation of a polysaccharide. Examples of the oligosaccharide composition include starch sugar (starch saccharified product), galacto-oligosaccharide, coupling sugar, fructooligosaccharide, xylo-oligosaccharide, soybean oligosaccharide, chitin oligosaccharide, chitosan oligosaccharide and the like. Among these oligosaccharide compositions, for example, the starch sugar may be a mixture of oligosaccharides to which a plurality of glucoses are bound.

  The oligosaccharide composition (or the oligosaccharide constituting the oligosaccharide composition) may have an oligosaccharide unit and a sugar alcohol unit bonded to the oligosaccharide unit. The sugar alcohol unit is usually often located at the end of the oligosaccharide unit. An oligosaccharide composition having such a sugar alcohol unit can be obtained, for example, by reducing an oligosaccharide composition (such as starch sugar).

  The oligosaccharide composition may contain a large number of relatively large multimeric oligosaccharides. For example, in the oligosaccharide composition, the content ratio of the oligosaccharides more than 20 saccharides is 20 wt% or more (for example, 25 to 100). % By weight), preferably 30% by weight or more (for example 35 to 90% by weight), more preferably 40% by weight or more (for example 45 to 80% by weight), particularly about 50 to 70% by weight, Usually, it may be about 40 to 75% by weight.

  Among these oligosaccharide compositions, starch sugar (for example, reduced starch saccharified product (trade name: PO-10) manufactured by Towa Kasei Kogyo Co., Ltd.) is particularly preferable.

  The oligosaccharide may be a reduced type (maltose type) or a non-reduced type (trehalose type), but a reduced oligosaccharide is preferable because of its excellent heat resistance.

  In order to effectively disperse (meth) acrylic resin particles, it is desirable that the oligosaccharide has a high viscosity. Specifically, when measured at a temperature of 25 ° C. using a B-type viscometer, the viscosity of a 50 wt% aqueous solution of oligosaccharide is, for example, 0.1 Pa · s or more (for example, about 0.2 to 2 Pa · s) ), Preferably 0.3 Pa · s or more (for example, 0.4 to 1.5 Pa · s, particularly about 0.45 to 1 Pa · s), more preferably 0.5 Pa · s or more (for example, 0.5 to 0.9 Pa · s).

  The melting point or softening point of the oligosaccharide is preferably higher than the heat distortion temperature of the (meth) acrylic resin. For oligosaccharides that do not exhibit a melting point or softening point and are thermally decomposed (for example, starch sugar such as reduced starch saccharified product), the decomposition temperature may be the “melting point or softening point” of the oligosaccharide. The temperature difference between the melting point or softening point of the oligosaccharide and the thermal deformation temperature of the (meth) acrylic resin is, for example, 1 to 80 ° C, preferably 10 to 70 ° C, and more preferably about 15 to 60 ° C.

  Of the oligosaccharides, the powdered oligosaccharide may be an oligosaccharide-containing granulated product that is granulated with a water-soluble plasticizing component described later from the viewpoint of safety and production efficiency. As a granulation method, the method described in JP 2007-046039 A can be used.

(A-2) Water-soluble polysaccharides having a cyclic structure Water-soluble polysaccharides having a cyclic structure have a high melt viscosity in melt kneading as compared with oligosaccharides, and thus have a high melt viscosity and are easily dissolved in water or the like. Can be removed. Therefore, the water-soluble auxiliary agent may be composed of a water-soluble polysaccharide having at least one cyclic structure together with or in place of the oligosaccharide.

  The cyclic structure may be a ring formed by glucoside bonding (or glucosylation) of a plurality of glycose units [usually glucose units (particularly D-glucose)] constituting the polysaccharide. The cyclic structure may be, for example, a cyclic structure having an α-1,4-glucoside bond and an α-1,6-glucoside bond.

  The average degree of polymerization of the cyclic structure (per one cyclic structure) is (number average degree of polymerization, average number of glucoside bonds forming the cyclic structure, average degree of polymerization of the glycose units forming the cyclic structure), 10 or more (for example, 10 to 10 About 500), preferably 12 or more (for example, about 12 to 300), and more preferably 14 or more (for example, about 14 to 100).

  The average degree of polymerization (number average degree of polymerization, total average degree of polymerization, average degree of polymerization of the whole polysaccharide) of the water-soluble polysaccharide having a cyclic structure is, for example, 14 or more (for example, about 14 to 15000), preferably 17 or more. (For example, about 17 to 10000), more preferably 20 or more (for example, about 20 to 8000) may be used.

  The water-soluble polysaccharide having a cyclic structure may be a derivative in which a hydroxyl group is derivatized (for example, etherified or esterified).

  The water-soluble polysaccharide having a cyclic structure may be used alone or in combination of two or more.

  As a water-soluble polysaccharide having a typical cyclic structure, for example, a polysaccharide having a cyclic structure and an acyclic structure bonded to the cyclic structure and having an average degree of polymerization of 50 or more (for example, cluster dextrin) A polysaccharide having one cyclic structure formed of 14 or more α-1,4-glucoside bonds in the molecule (for example, cycloamylose).

  For details of the water-soluble polysaccharide having a cyclic structure, JP-A No. 2007-119674 can be referred to.

  When the oligosaccharide (a-1) and the water-soluble polysaccharide (a-2) having a cyclic structure are combined, the ratio (weight ratio) of the both is, for example, the former / the latter = 1/99 to 99/1, preferably May be about 5/95 to 95/5, more preferably about 10/90 to 90/10 (for example, 15/85 to 85/15).

(B) Water-soluble plasticizing component The water-soluble auxiliary agent may contain a water-soluble plasticizing component in order to plasticize the oligosaccharide and the water-soluble polysaccharide having a cyclic structure. As the water-soluble plasticizing component, for example, sugar alcohol can be used.

  The sugar alcohol may be a chain sugar alcohol such as alditol (glycitol) or a cyclic sugar alcohol such as inosit. Usually, a chain sugar alcohol is used. These sugar alcohols can be used alone or in combination of two or more.

  Examples of chain sugar alcohols include tetritol (threitol, erythritol, etc.), pentitol [pentaerythritol, arabitol, ribitol, xylitol, lyxitol, etc.], hexitol [sorbitol, mannitol, iditol, glycitol, tallitol, dulcitol, allolucitol, arthritol] , Heptitol, octitol, nonitol, dexitol, dodecitol and the like. These can be used alone or in combination of two or more.

  The melting point or softening point of the water-soluble plasticizing component is usually not higher than the heat distortion temperature of the (meth) acrylic resin, but the oligosaccharide (a-1) and / or the water-soluble polysaccharide having a cyclic structure (a- The melting point or softening point of the sugar composition containing 2) and the water-soluble plasticizing component (b) is preferably higher than the heat distortion temperature of the (meth) acrylic resin.

  When the water-soluble auxiliary agent contains the water-soluble plasticizing component (b), the ratio (weight ratio) between the water-soluble saccharide (a) and the water-soluble plasticizing component (b) is determined by the water-soluble plastic As long as the chemical component is not localized due to aggregation or the like, for example, the former / the latter can be selected from 99/1 to 50/50, preferably 95/5 to 60/40, more preferably about 90/10 to 70/30. It may be.

  Details of the water-soluble plasticizing component of the water-soluble auxiliary agent are described in JP-A-2004-51942. The details of the sugar alcohol as the water-soluble plasticizing component are described in JP-A-2005-162841.

  The ratio (weight ratio) between the (meth) acrylic resin particles and the water-soluble auxiliary agent is, for example, the former / the latter = 1/99 to 60/40, preferably 5/95 to 50/50, more preferably 10 /. About 90-40 / 60 may be sufficient. In the method of the present invention, since the fusion of the resin particles can be suppressed even when the ratio (weight ratio) of the (meth) acrylic resin particles to the water-soluble auxiliary agent is large, the number density of the resin particles having a uniform shape High dispersion can be produced.

(Nonionic surfactant)
Among the surfactants, the nonionic surfactant is interposed between the (meth) acrylic resin and the water-soluble auxiliary agent to improve the stability of both, or the particle size of the (meth) acrylic resin particles is increased. It can be made uniform.

  Nonionic surfactants include polyhydric alcohol fatty acid ester or this ethylene oxide adduct, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid amide ethylene oxide adduct, alkylamine ethylene oxide adduct, Examples thereof include polyoxyethylene polyoxypropylene block copolymers. These nonionic surfactants can be used alone or in combination of two or more.

  Among these nonionic surfactants, in the ethylene oxide adduct, the number of ethylene oxide additions, that is, the number of oxyethylene units is, for example, 1 or more (1 to 100, preferably 2 to 50, more preferably 3 to 30). Degree).

  Of these nonionic surfactants, fatty acid esters of polyhydric alcohols or ethylene oxide adducts thereof (particularly fatty acid esters of polyhydric alcohols) are preferred.

A fatty acid ester of a polyhydric alcohol is formed of a polyhydric alcohol component and a fatty acid component. Examples of the polyhydric alcohol component include dihydric alcohols [eg, alkanediol (eg, ethylene glycol, propylene glycol, etc.), polyalkylene glycol (eg, poly C _2-5 alkylene glycol such as polyethylene glycol, polypropylene glycol, etc.), etc.] A trivalent or higher polyol [for example, (poly) glycerin, sucrose, sorbitan, etc.]. Of these components, trivalent or higher polyols (especially polyglycerin) such as (poly) glycerin are preferable. The average degree of polymerization of polyglycerol may be about 2 to 10 (for example, 2 to 9, preferably 3 to 8, more preferably 4 to 7).

Fatty acid components include saturated fatty acids [for example, higher saturated fatty acids (for example, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, melicic acid, lactelon) Saturated aliphatic monocarboxylic acids having 6 or more carbon atoms such as acid, gedamic acid, and ceplastic acid (for example, C _6-40 saturated aliphatic monocarboxylic acid, preferably C _8-30 saturated aliphatic monocarboxylic acid, more preferably C _10-20 saturated aliphatic monocarboxylic acid, especially C _10-20 alkane monocarboxylic acid, etc.], unsaturated fatty acids [eg higher unsaturated fatty acids (eg oleic acid, erucic acid, erucic acid, linoleic acid, linolenic acid) Unsaturated aliphatic monocarboxylic acids having 12 or more carbon atoms such as acid and eleostearic acid (for example, C _12-40 unsaturated aliphatic monocarboxylic acid, preferably C _14-36 unsaturated aliphatic monocarboxylic acid, more preferably C _16-32 unsaturated aliphatic monocarboxylic acid) and the like. Of these, higher saturated fatty acids, preferably C _8-30 alkane monocarboxylic acids, particularly C _10-20 alkane monocarboxylic acids such as lauric acid are preferred.

  In the fatty acid ester of a polyhydric alcohol, the ester average substitution degree of the polyhydric alcohol may be, for example, 50 to 100%, preferably 60 to 99.9%, and more preferably about 70 to 99%.

Typical polyhydric alcohol fatty acid esters include (poly) glycerin mono (or di) capric acid ester, (poly) glycerin mono (or di) lauric acid ester, (poly) glycerin mono (or di) myristic acid ester, (Poly) glycerin mono (or di) palmitic acid ester, (poly) glycerin mono (or di) stearic acid ester (poly) glycerin C _10-20 alkanoic acid ester; sucrose monolauric acid ester etc. sucrose C _{10 -20} fatty acid esters; and sorbitan _{C 10-20} fatty acid esters such as sorbitan monolaurate can be exemplified. Of these polyhydric alcohol fatty acid esters, polyglycerin C _10-20 alkanoic acid esters such as polyglycerin laurate are particularly preferred.

  The HLB of the nonionic surfactant may be, for example, about 1 to 20, preferably 2 to 15, more preferably about 3 to 10 (particularly 4 to 9). In this invention, since HLB exists in this range, it is estimated that it exists stably between a (meth) acrylic-type resin particle and a water-soluble auxiliary agent, and can suppress the increase in particle | grains. HLB may be adjusted according to the type of resin or oligosaccharide by adjusting the number of moles of ethylene oxide or glycerin added.

  The molecular weight of the nonionic surfactant (in the case of an alkylene oxide adduct, polyalkylene glycol fatty acid ester or polyglycerin fatty acid ester, the weight average molecular weight) is, for example, 100 to 50,000, preferably 500 to 10,000, and more preferably. May be about 1,000 to 5,000.

  The ratio of the (meth) acrylic resin particles to the nonionic surfactant is, for example, the former / the latter (weight ratio) = 99.9 / 0.1-50 / 50, preferably 99 / 1-60 / 40, Preferably, it may be about 90/10 to 70/30. If the nonionic surfactant is in the above range, it is considered that resin particles having a uniform particle diameter can be produced by appropriate shearing and fusion of (meth) acrylic resin particles.

(Optional component)
The dispersion of the present invention may contain a modifier as necessary. Examples of the modifier include conventional modifiers such as plasticizers (or softeners), fillers (such as granular fillers), photodegradability imparting agents (such as anatase-type titanium oxide), lubricants, stabilizers (heat) Stabilizers, antioxidants, UV absorbers, weather (light) stabilizers, processing stabilizers, etc.), UV scattering agents (powder of metal oxides such as titanium oxide, zirconium oxide, zinc oxide, iron oxide, etc.), Examples include dispersants, flame retardants, antistatic agents, colorants (dyes or pigments, etc.), charge control agents, mold release agents, brighteners, wettability improvers, fluidizing agents, crosslinking agents, antibacterial agents, preservatives, etc. it can.

  The ratio of the optional component is, for example, 0.01 to 100 parts by weight, preferably 0.05 to 50 parts by weight, more preferably 100 parts by weight of the total of (meth) acrylic resin particles and water-soluble auxiliary agent. It may be about 0.1 to 30 parts by weight.

[Method for producing dispersion]
When the time-dependent change in the particle size of the resin particles formed by melt-kneading with a water-soluble auxiliary agent was examined, the average particle size of the resin particles and the coefficient of variation of the average particle size for the polyamide-based resin and the polyester-based resin are the kneading time In contrast to (meth) acrylic resin, the average particle size of the resin particles decreases and then increases as the kneading time elapses. It has been found that the coefficient of variation of the average particle diameter repeatedly decreases and increases. Therefore, when producing (meth) acrylic resin particles, it is difficult to control the particle size distribution width based on the kneading time, and it is difficult to industrially produce resin particles with a narrow particle size distribution width. is there. However, in the method of the present invention, by using a nonionic surfactant, a dispersion of (meth) acrylic resin particles having a narrow particle size distribution width can be easily produced using the kneading time as one index.

  The dispersion of the present invention is produced by melt-kneading a (meth) acrylic resin and a water-soluble auxiliary agent in the presence of a nonionic surfactant. A (meth) acrylic resin and a nonionic surfactant and / or additive are pre-kneaded using a kneader (for example, a mixer such as a Henschel mixer, a tumble mixer or a ribbon mixer, a ball mill, etc.). Also good. A nonionic surfactant may be present in the reaction system at the start of kneading with the matrix component, but a nonionic surfactant may be added as necessary in the kneading stage.

  The melt-kneading can be performed using a conventional kneader (for example, a single or twin screw extruder, a kneader, a calender roll, a Banbury mixer, etc.). You may melt-knead these kneaders individually or in combination of 2 or more types.

  In the melt-kneading, the kneading temperature can be adjusted according to the heat deformation temperature of the (meth) acrylic resin, for example, 120 to 300 ° C, preferably 130 to 280 ° C, more preferably 150 to 260 ° C (for example, 160 to 260 ° C). It may be about 240 ° C.

  The kneading time and stirring speed (rotational speed) can be appropriately selected according to the shape of both components to be used for melt kneading, the type of kneader, the desired particle size, etc., and the kneading time is preferably 10 seconds to 2 hours, for example. May be about 30 seconds to 1 hour, more preferably about 1 to 40 minutes (for example, 3 to 20 minutes). The stirring speed may be about 1 to 150 rpm, preferably 5 to 140 rpm, more preferably 10 to 130 rpm (particularly 20 to 100 rpm).

[Method for producing (meth) acrylic resin particles]
(Meth) acrylic resin particles can be produced by removing the matrix phase from the dispersion.

  The method of removing the matrix phase is a case where the water-soluble auxiliary is eluted (or washed) with a solvent that is a poor solvent for the (meth) acrylic resin and a good solvent for the water-soluble auxiliary. Many. In this method, the matrix phase can be removed while maintaining the shape and size of the (meth) acrylic resin particles of the dispersion.

  Examples of the solvent include water, water-soluble solvents [eg, alcohols (methanol, ethanol, propanol, etc.), ethers (cellosolve, butyl cellosolve, etc.), etc.]. These solvents can be used alone or in combination of two or more. Of these solvents, water is preferred because it has less burden on the environment and can reduce industrial costs.

  For elution of the water-soluble auxiliary agent, a conventional method, for example, a method of immersing and dispersing the dispersion in the solvent to elute or wash (transfer to the solvent) the water-soluble auxiliary agent can be mentioned. When the dispersion is immersed in the solvent, the water-soluble auxiliary agent that forms the matrix phase of the dispersion is gradually eluted, and the dispersed phase is dispersed in the eluate.

  The water-soluble auxiliary agent can be eluted under normal pressure (for example, about 100,000 Pa), reduced pressure or increased pressure. The elution temperature of the water-soluble auxiliary agent can be appropriately set according to the type of the (meth) acrylic resin and the water-soluble auxiliary agent, and is usually a temperature lower than the thermal deformation temperature of the (meth) acrylic resin. For example, it is about 10-100 degreeC, Preferably it is 25-90 degreeC, More preferably, it is about 30-80 degreeC (for example, 40-80 degreeC).

  The (meth) acrylic resin particles can be recovered from the eluate of the water-soluble auxiliary agent in which the dispersed phase is dispersed by using a conventional separation (recovery) method such as filtration or centrifugation.

  The separated (meth) acrylic resin particles may be dried. Drying may be natural drying or may be performed using a dryer (hot air dryer or the like). Although drying temperature is based also on the kind of solvent, for example, 30-150 degreeC, Preferably it is 35-100 degreeC, More preferably, about 40-70 degreeC may be sufficient.

  In addition, the water-soluble auxiliary agent eluted with the solvent can be recovered using a conventional separation means (for example, distillation, concentration, recrystallization, drying (freeze drying), etc.).

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
30 parts by weight of polymethyl methacrylate (made by Asahi Kasei Chemicals Corporation, Delpet 720V) as a (meth) acrylic resin, and reduced starch saccharified product (Towa Kasei Kogyo Co., Ltd., PO-) as a water-soluble auxiliary agent 10) 90 parts by weight and 10 parts by weight of sorbitol (manufactured by Towa Kasei Kogyo Co., Ltd.) and 4 parts by weight of polyglycerin lauric acid ester (manufactured by Taiyo Kagaku Co., Ltd., Tirabazole P-4) as an additive It was melt-kneaded with a lavender (Toyo Seiki Co., Ltd., Labo Plast Mill) at a rotation speed of 50 rpm and a temperature of 220 ° C. And the dispersion whose melt-kneading time is 1 minute, 2 minutes, 3 minutes, 5 minutes, 10 minutes, and 20 minutes was obtained.

  The obtained dispersion was immersed in water at 25 ° C. to obtain a suspension of resin particles (composite resin particles). Using a membrane membrane (pore diameter 0.45 μm, made of cellulose acetate), insolubles were separated from the suspension, and resin particles were recovered. The recovered resin particles were dispersed in distilled water 20 times by weight with respect to the particles, and stirred for 10 minutes using a magnetic stirrer to obtain a suspension. Thereafter, again using a membrane membrane (pore diameter 0.45 μm, made of cellulose acetate), insolubles were separated from the suspension, and resin particles were recovered.

  The obtained resin particles were observed with a scanning electron microscope (manufactured by JEOL Ltd., FE-SEM, JSM-6700F) to obtain a photograph of the entire shape. Then, using the obtained scanning electron micrograph, draw a rectangle of an arbitrary size so that at least 200 particles are included on the photograph, and the particle diameter at the time of true sphere conversion of all particles present in the rectangle Measured. The number average particle diameter (Dn), volume average particle diameter (Dw), and coefficient of variation (Cv) of the average particle diameter were obtained from the obtained at least 200 particle diameters.

  Table 1 shows Dn, Dw, and CV of the polymethyl methacrylate resin particles in each kneading time.

  As is clear from Table 1, the number average particle size and the coefficient of variation of the average particle size decreased corresponding to the kneading time.

Comparative Example 1
It was carried out under the same conditions as in Example 1 except that the nonionic surfactant was not added and polymethyl methacrylate and a water-soluble auxiliary were melt kneaded.

  Table 2 shows Dn, Dw, and CV of the polymethyl methacrylate resin particles in each kneading time.

  As is apparent from Table 2, the number average particle diameter decreased until the kneading time of 3 minutes, whereas the number average particle diameter increased after the kneading time of 3 minutes. Regarding the coefficient of variation of the average particle diameter, reduction and increase were repeated between about 35 to 50%.

  Table 3 shows the values of Dn, Dw, and CV of the polymethyl methacrylate resin particles contained in the dispersions of Example 1 and Comparative Example 1 when melt-kneaded for 10 minutes.

  As is clear from Table 3, in Example 1, the coefficient of variation of the average particle diameter is 9% smaller than that in Comparative Example 1, and the particle size distribution width is narrow. Further, the number average particle size was reduced by about 50%, and the volume average particle size was reduced by about 60%.

  In the present invention, (meth) acrylic resin particles having a desired size and a narrow particle size distribution width can be efficiently and industrially produced, so that the production cost can be greatly reduced, and the (meth) acrylic resin is inexpensive. Resin particles can be provided. The resin particles can be used in any field or application, and can be effectively used for cosmetics, inks, paints, coating agents, liquid crystal panel spacers, and the like.

Claims (11)

  A dispersion composed of a dispersed phase formed of (meth) acrylic resin particles and a matrix phase formed of a water-soluble auxiliary agent, the dispersion including a nonionic surfactant.   The dispersion according to claim 1, wherein the (meth) acrylic resin particles are particles that exhibit a behavior that increases after the average particle diameter decreases with the passage of kneading time in melt kneading with a water-soluble auxiliary agent. .   The dispersion according to claim 1 or 2, wherein the coefficient of variation of the average particle diameter of the (meth) acrylic resin particles is 30 or less.   The dispersion according to any one of claims 1 to 3, wherein the (meth) acrylic resin particles are composed of a homopolymer or a copolymer of an alkyl (meth) acrylate.   The dispersion according to any one of claims 1 to 4, wherein the nonionic surfactant is a fatty acid ester of a polyhydric alcohol having HLB 1 to 10.   The dispersion according to any one of claims 1 to 5, wherein the nonionic surfactant is composed of at least one component selected from (poly) glycerin fatty acid ester, sorbitan fatty acid ester, and sucrose fatty acid ester.   The ratio (weight ratio) between the (meth) acrylic resin particles and the nonionic surfactant is the former / the latter = 99.9 / 0.1-50 / 50. Dispersion.   The dispersion according to any one of claims 1 to 7, wherein a ratio (weight ratio) between the (meth) acrylic resin particles and the water-soluble auxiliary agent is the former / the latter = 1/99 to 60/40.   In the presence of a nonionic surfactant, a (meth) acrylic resin and a water-soluble auxiliary are melt-kneaded, and a dispersed phase formed of (meth) acrylic resin particles and a matrix phase formed of a water-soluble auxiliary A method for producing a structured dispersion.   The method of manufacturing a (meth) acrylic-type resin particle by removing a matrix phase from the dispersion in any one of Claims 1-8.   A method for reducing a coefficient of variation in average particle diameter of (meth) acrylic resin particles by melt-kneading a (meth) acrylic resin and a water-soluble auxiliary agent in the presence of a nonionic surfactant.