JP6613881B2 - Polymer fine particles, method for producing the same, epoxy resin composition and semiconductor encapsulant - Google Patents

Description

  The present invention relates to polymer fine particles composed of a thermoplastic styrene-based elastomer, an epoxy resin composition in which the polymer fine particles are dispersed, and a semiconductor sealing material using the epoxy resin composition.

  Polymer fine particles are fine particles made of polymer. Unlike molded products such as injection molded products, extrusion molded products, and films, polymer fine particles have a large specific surface area and are spherical. It is used as. Thermoplastic styrene-based elastomers have rubber elasticity in a wide temperature range and have excellent heat resistance and chemical resistance, and are used for adhesives, adhesives, asphalt modifiers, etc. . The fine particles comprising such a thermoplastic styrene elastomer have (1) a pulverization method, (2) an emulsion polymerization method, and (3) a dispersion stabilizer in an oil phase in which a thermoplastic styrene elastomer is dissolved in an organic solvent. It is obtained by a method such as a method of removing an organic solvent after adding an aqueous phase and preparing an emulsion by mechanical stirring (Patent Documents 1 and 2).

  On the other hand, a semiconductor sealing material for protecting a semiconductor from external stimuli such as heat and impact is generally composed of an additive such as an epoxy resin and a filler, a low stress agent, and a flame retardant. The stress reducing agent plays a role in relieving internal stress generated when the matrix resin undergoes a volume change due to thermal changes during semiconductor operation or during molding of the sealing material. Prevent damage. In order for the stress reducing agent to relieve the internal stress of the sealing material, those having a low elastic modulus of the stress reducing agent are preferably used. As the stress reducing agent, silicone fine particles and rubber fine particles having a core-shell structure (patented) Document 3) or elastomer resin that has been pulverized and pulverized is widely used (Patent Document 4). Furthermore, in recent years, electronic devices have been downsized, and in order to prevent damage to the semiconductor element and the lead frame that connects the semiconductor and the substrate, it is necessary to refine the additive and improve the fluidity of the sealing material. It is getting to be. In addition to this, in particular, with respect to an in-vehicle semiconductor or a power semiconductor, the operating temperature of the semiconductor tends to be high, so that heat resistance higher than that of a normal sealing material is required.

JP 2000-212287 A JP-A-6-166757 JP 2006-193619 A JP-A 63-248820

  A stress reducing agent for a semiconductor encapsulant is required to be fine and have high heat resistance that can withstand an operating environment at a high temperature so as not to damage internal semiconductor elements and lead frames. Further, in order to effectively exert the stress reduction ability by adding a small amount, it is desirable that the stress reducing agent is uniformly dispersed in the state of primary particles without agglomerating inside the sealing material. Since the fine particles described in Patent Document 3 are not dispersed by primary particles, the stress reduction is insufficient. In addition, as a raw material for a stress reducing agent for a semiconductor encapsulant, a thermoplastic styrene-based elastomer may be effective from the viewpoint of heat resistance and elastic modulus. Then, there is a limit to miniaturization of the polymer fine particles, and it is difficult to uniformly disperse in the sealing material. In addition, in order to obtain thermoplastic styrene elastomer fine particles by the emulsion polymerization method, it is difficult to take out the polymer fine particles from the emulsion after the emulsion polymerization. As a method of taking out the fine particles, there is a method of adding salt to salt out, but the salt remains. Furthermore, the fine particles after salting out become secondary aggregates and do not disperse in the sealing material as fine fine particles. Furthermore, in the methods of Patent Documents 1 and 2, the droplet sizes are not uniform, the particle size is difficult to control, the particle size distribution of the resulting fine particles is widened, and the solvent removal process increases and becomes complicated. is there.

As a result of intensive studies by the present inventors in order to achieve the above object, the following invention has been achieved.
That is, the present invention
“(1) A thermoplastic styrene-based elastomer characterized by being a styrene-ethylenebutylene copolymer and a block copolymer of styrene, having an average particle size of 0.5 μm or more and 100
Polymer fine particles having a particle size distribution index of less than 3 and not more than μm.
(2) The polymer fine particles according to (1), wherein the average particle size is more than 1 μm and 100 μm or less.
(3) The polymer fine particles according to (1) or (2), wherein the sphericity is 80 or more.
(4) The polymer fine particle according to any one of (1) to (3), wherein a salt containing an alkali metal and an alkaline earth metal contained in the polymer fine particle is 1% by mass or less.
( 5 ) An epoxy resin composition comprising an epoxy resin and polymer fine particles according to any one of (1) to ( 4 ).
( 6 ) The epoxy resin composition according to ( 5 ), comprising 0.1 to 50 parts by mass of polymer fine particles according to any one of (1) to ( 4 ) with respect to 100 parts by mass of the epoxy resin.
( 7 ) A semiconductor sealing material comprising the epoxy resin composition according to ( 5 ) or ( 6 ). Is.

  According to the present invention, fine polymer particles having excellent heat resistance, low elasticity, and useful as a powder-like low stress agent without aggregation can be obtained. Furthermore, the epoxy resin composition containing the polymer fine particles of the present invention is capable of effectively relieving internal stress even with a small amount, since the polymer fine particles are dispersed as primary particles. The epoxy resin composition is a very suitable material for a semiconductor sealing material.

  Hereinafter, the present invention will be described in detail.

  The present invention relates to polymer fine particles comprising a thermoplastic styrene-based elastomer, having an average particle size of 0.5 μm or more and 100 μm or less, and a particle size distribution index of less than 3, an epoxy resin composition containing the fine particles, and an epoxy resin thereof The present invention relates to a semiconductor sealing material using the composition.

  In the present invention, polymer fine particles refer to polymer powder dispersed with primary particles. However, in the present invention, the polymer fine particles do not include core-shell type fine particles.

  The average particle size of the polymer fine particles in the present invention is 0.5 μm or more as a lower limit, preferably 1 μm or more, more preferably more than 1 μm, still more preferably 5 μm or more, and particularly preferably 10 μm. That's it. Moreover, as an upper limit of an average particle diameter, it is 100 micrometers or less, Preferably it is 80 micrometers or less, More preferably, it is 50 micrometers or less. When the average particle diameter of the polymer fine particles is within this range, the internal stress can be effectively relieved when a composition containing an epoxy resin and polymer fine particles is used.

  Further, the particle size distribution in the present invention is less than 3 as a particle size distribution index, and is 2 or less according to a preferred embodiment, 1.5 or less according to a more preferred embodiment, and further preferred embodiments. For example, it is 1.2 or less, and according to a particularly preferred embodiment, it is 1.1 or less. In theory, the lower limit is 1. When the particle size distribution of the polymer fine particles is within this range, it can be uniformly dispersed when dispersed in an epoxy resin or the like, so that the internal stress can be effectively relieved.

  The average particle diameter of the polymer fine particles in the present invention can be calculated by specifying an arbitrary 100 fine particle diameters from a scanning electron micrograph and calculating the arithmetic average according to the following equation. In that case, the scanning electron micrograph is measured at a magnification of at least 300 times, preferably at least 500 times. Further, the particle size distribution index is determined based on the value of the fine particle diameter obtained above based on the following numerical conversion formula. At this time, when the fine particles are not true spheres, the major axis is taken as the particle size, and when the fine particles are overlapped and aggregated, the aggregate is regarded as one fine particle, and the major axis is measured as the particle size.

  Ri: particle diameter of each fine particle, n: number of measurement 100, Dn: number average particle diameter, Dv: volume average particle diameter, PDI: particle diameter distribution index.

  The shape of the polymer fine particles in the present invention is preferably spherical. The degree of sphericity of the shape can be expressed by sphericity, but the higher the sphericity, the better the dispersibility in the epoxy resin, and the more uniformly it can be dispersed.

  The sphericity of the polymer fine particles in the present invention is preferably 80 or more, more preferably 85 or more, still more preferably 90 or more, particularly preferably 92 or more, and most preferably 95 or more. . The upper limit is 100. The sphericity is calculated according to the following equation by observing particles with a scanning electron microscope, measuring the short diameter and long diameter of 30 arbitrary particles.

  Note that n is 30 measurements.

  The thermoplastic elastomer in the present invention is a block copolymer composed of a soft segment exhibiting rubber elasticity in a molecule and a hard segment that prevents plastic deformation. In particular, a thermoplastic styrene elastomer is a hard segment component. Is a block copolymer formed of an aromatic vinyl hydrocarbon polymer.

  The soft segment component of the thermoplastic styrene elastomer in the present invention is not particularly limited, but ethylene-propylene copolymer, polybutadiene, poly (1,3-pentadiene), poly (2,3-dimethyl-1,3). -Butadiene), polyisoprene, polymethylisoprene, polypropylene, and hydrogenated products thereof. Of these, polyisoprene and polybutadiene are more preferable, and polybutadiene is most preferable.

  Examples of the aromatic vinyl hydrocarbon copolymer that is a hard segment component include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, 1,3-dimethylstyrene, vinylnaphthalene, 2,6-dimethyl. Styrene, 2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene, α-methyl-p-methylstyrene, chlorostyrene, α-chloro-o-methylstyrene, α- Among chloro-m-methylstyrene, α-chloro-p-methylstyrene, 2,4,6-trichlorostyrene, α-chloro-2,6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, etc. A polymer obtained by polymerizing at least one or more types of monomers is exemplified. Of these, styrene polymers are preferred.

  There are many combinations of the hard segment component and the soft segment component, and there is no particular limitation, but an ABA type triblock copolymer in which the soft segment is sandwiched between the hard segments is preferable. Examples thereof include styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, and hydrogenated copolymers and maleic anhydride-modified products thereof. From the viewpoint of heat resistance and elastic modulus, a styrene-ethylenebutylene copolymer-styrene block copolymer, which is a hydrogenated copolymer of styrene-butadiene-styrene block copolymer, is most preferred.

  The proportion of the hard segment component contained in the thermoplastic styrene-based elastomer is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 20% by mass or more as the lower limit. Moreover, as an upper limit of the ratio for which a hard segment component accounts, it is preferable that it is 80 mass% or less, More preferably, it is 50 mass% or less, More preferably, it is 40 mass% or less. When the proportion of the hard segment component is large, the particles have a high elastic modulus, so that the effect as a stress reducing agent is hardly exhibited.

  The polymer fine particles in the present invention preferably have a salt containing an alkali metal and an alkaline earth metal contained in the polymer fine particles in an amount of 1% by mass or less. The alkali metal here refers to group 1 of the periodic table excluding hydrogen. It is an element to which it belongs, and refers to lithium, sodium, potassium, rubidium, cesium, and francium.

  Alkaline earth metal is an element belonging to Group 2 of the periodic table, and refers to beryllium, magnesium, calcium, strontium, barium, and radium.

  Salts containing alkali metals and alkaline earth metals are lithium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, lithium bromide, sodium bromide, potassium bromide, lithium fluoride, sodium fluoride, fluoride. Examples include potassium, lithium acetate, sodium acetate, potassium acetate, calcium acetate, magnesium acetate, lithium carbonate, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, sodium sulfate, magnesium sulfate, and calcium sulfate. When these salts are contained in the polymer fine particles, the polymer fine particles are likely to be secondarily aggregated and are not easily dispersed uniformly in the epoxy resin composition described below.

  “The salt containing an alkali metal and an alkaline earth metal is 1% by mass or less” means that the alkali metal and alkaline earth metal contained in the polymer fine particles are subjected to atomic absorption spectrometry, ICP emission spectroscopic analysis, ICP mass. It means that the content of a salt containing an alkali metal and an alkaline earth metal determined by an analysis method or the like is 1% by mass or less. The content of the salt containing an alkali metal and an alkaline earth metal is preferably small, and the lower limit is 0% by mass, but the lower limit of measurement is usually 0.001% by mass.

  In order to produce thermoplastic styrene-based elastomer fine particles having characteristics effective for the above-described stress reducing agent, the following method can be employed.

  When a polymer A which is a thermoplastic styrene elastomer, a polymer B different from the polymer A, and an organic solvent are dissolved and mixed, a solution phase mainly composed of the polymer A and a solution phase mainly composed of the polymer B In a system that separates into two phases, after forming an emulsion, a method of obtaining polymer A fine particles by bringing polymer A into contact with a poor solvent of polymer A and precipitating polymer A can be mentioned.

  “A system in which polymer A, polymer B, and an organic solvent are dissolved and mixed, and phase-separated into two phases, a solution phase mainly composed of polymer A and a solution phase mainly composed of polymer B” means polymer A and polymer When B and an organic solvent are mixed, it refers to a system that is divided into two phases: a solution phase mainly containing polymer A and a solution phase mainly containing polymer B. By using such a phase-separating system, it is possible to emulsify and form an emulsion by applying a shearing force by mixing under conditions for phase separation.

  In the above, whether or not the polymer is dissolved is more than 1% by mass with respect to the organic solvent at the temperature at which the present invention is carried out, that is, the temperature at which the polymer A and the polymer B are dissolved and mixed and separated into two phases. Judged by whether or not to dissolve.

  This emulsion has a polymer A solution phase as a dispersed phase and a polymer B solution phase as a continuous phase. By contacting the emulsion with a polymer A poor solvent, the polymer A solution phase from the polymer A solution phase in the emulsion is polymerized. A precipitates, and polymer fine particles composed of the polymer A can be obtained.

  In the production method of the present invention, polymer A, polymer B, an organic solvent for dissolving them, and a poor solvent for polymer A are used. The polymer B, the organic solvent, and the poor solvent are described in detail below.

  The polymer B in the present invention preferably has a high affinity with a poor solvent described later, and the affinity index can be determined by the solubility in water or ethanol. When the solubility of polymer B in water or ethanol at 25 ° C. is defined as 1 g / 100 g when 1 g is dissolved in 100 g of water or ethanol, it is preferably 1 g / 100 g or more, more preferably It is 2g / 100g or more, More preferably, it is 5g / 100g or more, Especially preferably, it is 10g / 100g or more, Most preferably, it is 15g / 100g or more. If it is this range, it has high affinity with the poor solvent mentioned later, and functions advantageously in this polymer fine particle manufacturing method.

  As the polymer type of the polymer B, those having a hydroxyl group, an ether group, an amide group, or a carboxyl group in the molecular skeleton are particularly preferable.

  If polymer B is specifically exemplified, those having a hydroxyl group in the molecular skeleton include polyvinyl alcohols (fully saponified or partially saponified poly (vinyl alcohol), fully saponified or partially saponified). Poly (vinyl alcohol-ethylene) copolymers such as modified poly (vinyl alcohol-ethylene) copolymers), poly (paravinylphenol), disaccharides such as maltose, cellobiose, lactose, sucrose, cellulose and Derivatives (hydroxyalkylcellulose (hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, etc.), cellulose, methylcellulose, ethylcellulose, carboxymethylethylcellulose, carboxymethylcellulose, carboxymethylcellulose Sodium, cellulose ester, chitosan, etc.), amylose and derivatives thereof, starch and derivatives thereof, polysaccharides or derivatives thereof such as dextrin, cyclodextrin, sodium alginate and derivatives thereof, gelatin, casein, collagen, albumin, fibroin, keratin, fibrin , Carrageenan, chondroitin sulfate, gum arabic, agar, protein and the like, and those having an ether group in the molecular skeleton include polyalkylene glycol, sucrose fatty acid ester, poly (oxyethylene fatty acid ester), poly (oxy Ethylene laurin fatty acid ester), poly (oxyethylene glycol mono fatty acid ester), poly (oxyethylene alkylphenyl ether), poly (oxyalkyl ether) Examples include those having an amide group in the molecular skeleton, such as polyvinylpyrrolidone, aminopoly (acrylamide), poly (acrylamide), poly (methacrylamide), and “AQ nylon (registered trademark)”. Water-soluble nylons such as (A-90, P-70, P-95, T-70; manufactured by Toray Industries, Inc.) and the like can be mentioned, and those having a carboxyl group in the molecular skeleton include polyacrylic acid, poly Examples include sodium acrylate, polymethacrylic acid, polysodium methacrylate, and the like. In addition, polystyrene sulfonic acid, sodium polystyrene sulfonate, polyvinyl pyrrolidinium chloride, poly (styrene-maleic acid) copolymer, polyallylamine, Poly (oxyethyleneamine), poly And synthetic resins such as (vinyl pyridine), polyaminosulfone, and polyethyleneimine.

  Preferably, cellulose derivatives (carboxymethyl cellulose, hydroxyalkyl cellulose (hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose), methyl cellulose, ethyl cellulose, carboxymethyl ethyl cellulose, carboxymethyl cellulose, carboxymethyl cellulose sodium, cellulose ester, etc.), polyvinyl alcohols (Poly (vinyl alcohol-ethylene) copolymers such as fully saponified and partially saponified poly (vinyl alcohol) and fully saponified and partially saponified poly (vinyl alcohol-ethylene) copolymers ), Polyalkylene glycol, sucrose fatty acid ester, poly (oxyethylene alkylphenyl ether), poly (oxyalkyl ether) ), Polyvinyl pyrrolidone, water-soluble nylon, polyacrylic acid, polymethacrylic acid, more preferably poly (vinyl alcohol) s (fully saponified or partially saponified poly (vinyl alcohol), fully saponified) And partially saponified poly (vinyl alcohol-ethylene) copolymers such as poly (vinyl alcohol-ethylene) copolymers, cellulose derivatives (carboxymethylcellulose, hydroxyalkylcellulose (hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxy) Ethyl cellulose), methyl cellulose, ethyl cellulose, carboxymethyl ethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose ester, etc.), polyalkylene glycol, poly Is Nirupiroridon.

  In particular, when the polymer A is a block copolymer of styrene-ethylenebutylene copolymer-styrene, a cellulose derivative (carboxymethylcellulose, hydroxyalkylcellulose (hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose), methylcellulose, ethylcellulose, carboxymethyl) Ethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose ester, etc.) are preferred, and hydroxypropyl cellulose is particularly preferred.

  Although it does not specifically limit as a weight average molecular weight of the polymer B, As a minimum, 1,000 or more are preferable, More preferably, it is 5,000 or more, More preferably, it is 10,000 or more. Moreover, as an upper limit, Preferably it is 100,000,000 or less, More preferably, it is 10,000,000 or less, More preferably, it is 1,000,000 or less, Most preferably, it is 500,000 or less. Yes, most preferably 200,000 or less.

  The weight average molecular weight of the polymer B here refers to a weight average molecular weight measured by gel permeation chromatography (GPC) using water as a solvent and converted into polyethylene glycol.

  Use dimethylformamide when it cannot be measured with water, use tetrahydrofuran when it cannot be measured with water, and use hexafluoroisopropanol when it cannot be measured with water.

  A plurality of these polymers B may be used, or may be used as a mixture.

  The organic solvent that dissolves the polymer A and the polymer B is an organic solvent that can dissolve the polymer A and the polymer B to be used, and is selected according to the type of each polymer.

  Specific examples include aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, n-decane, n-dodecane, n-tridecane, tetradecane, cyclohexane, cyclopentane, benzene, toluene, xylene, 2- Aromatic hydrocarbon solvents such as methyl naphthalene, ester solvents such as ethyl acetate, methyl acetate, butyl acetate, butyl propionate, butyl butyrate, ethyl acetoacetate, chloroform, bromoform, methylene chloride, carbon tetrachloride, 1, 2 -Halogenated hydrocarbon solvents such as dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, hexafluoroisopropanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and methyl butyl ketone, methanol Alcohol solvents such as ethanol, 1-propanol, 2-propanol, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA ), Aprotic polar solvents such as propylene carbonate, trimethyl phosphoric acid, 1,3-dimethyl-2-imidazolidinone, sulfolane, carboxylic acid solvents such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, anisole, diethyl ether , Tetrahydrofuran, diisopropyl ether, dioxane, diglyme, dimethoxyethane, and other ether solvents, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium hydrogen sulfate, 1-ethyl-3-imidazole Um acetate, ionic liquids or mixtures thereof, such as 1-ethyl-3-methylimidazolium thiocyanate, and the like. Preferred are aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, ether solvents, aprotic polar solvents, carboxylic acid solvents, and more preferred are ether solvents, aprotic polar solvents, carboxylic solvents. It is an acid solvent. Most preferred are N-methyl-2-pyrrolidone, dimethyl sulfoxide, and tetrahydrofuran because they are easily available and can be uniformly mixed with a solvent that can be preferably used as a poor solvent described later, such as water and alcohol solvents.

  In particular, when polymer A is a styrene-ethylenebutylene copolymer-styrene block copolymer, tetrahydrofuran is most preferred.

  These organic solvents may be used in a plurality of types, or may be used as a mixture. However, it is possible to obtain fine particles having a relatively small particle size and a small particle size distribution, which is a reduction in manufacturing process load. From the viewpoint, a single organic solvent is preferable, and a single organic solvent that dissolves both the polymer A and the polymer B is more preferable.

  The poor solvent for polymer A in the present invention refers to a solvent that does not dissolve polymer A. When the solvent is not dissolved, the solubility of the polymer A in the poor solvent is 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.1% by mass or less.

  In the production method of the present invention, a poor solvent for polymer A is used, and the poor solvent is preferably a poor solvent for polymer A and a solvent that dissolves polymer B. Thereby, the polymer fine particle comprised with the polymer A can be precipitated efficiently. Moreover, it is preferable that the solvent for dissolving the polymer A and the polymer B and the poor solvent for the polymer A are solvents that are uniformly mixed.

  The poor solvent in the present invention varies depending on the type of polymer A to be used, desirably both types of polymers A and B, but specifically, pentane, hexane, heptane, octane, nonane, n -Aliphatic hydrocarbon solvents such as decane, n-dodecane, n-tridecane, cyclohexane and cyclopentane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; chloroform Halogenated hydrocarbon solvents such as bromoform, methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl butyl ketone, etc. Ketone solvents, methanol, ethanol, Alcohol solvents such as propanol-2-propanol, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, trimethyl phosphoric acid, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazo Aprotic polar solvents such as lysinone and sulfolane, carboxylic acid solvents such as formic acid, acetic acid, propionic acid, butyric acid and lactic acid, ether solvents such as anisole, diethyl ether, tetrahydrofuran, diisopropyl ether, dioxane, diglyme and dimethoxyethane, Examples include a solvent selected from at least one of water.

  From the viewpoint of efficiently atomizing the polymer A, an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, an alcohol solvent, an ether solvent, and water are preferable, and an alcohol solvent, water is most preferable. It is.

  In particular, when the polymer A is a styrene-ethylenebutylene copolymer-styrene block copolymer, an alcohol solvent or water is preferable, and ethanol is most preferable among alcohol solvents.

  In the present invention, polymer A can be efficiently precipitated and polymer fine particles can be obtained by appropriately selecting and combining polymer A, polymer B, an organic solvent for dissolving them, and a poor solvent for polymer A.

  The conditions for generating the state of two-phase separation are the types of polymers A and B, the weight average molecular weight of polymers A and B, the molecular weight distribution, the type of organic solvent, the concentration of polymers A and B, the temperature at which the invention is to be carried out, It depends on the pressure.

  In order to obtain conditions that are likely to cause a phase separation state, it is preferable that the difference between the solubility parameters of the polymer A and the polymer B (hereinafter also referred to as SP values) is separated.

At this time, the difference in SP value is 1 (J / cm ³ ) ^1/2 or more, more preferably 2 (J / cm ³ ) ^1/2 or more, and further preferably 3 (J / cm ³ ) ^1/2 or more. Particularly preferably, it is 5 (J / cm ³ ) ^1/2 or more, and very preferably 8 (J / cm ³ ) ^1/2 or more. When the SP value is within this range, phase separation is easily performed.

There is no particular limitation as long as both polymer A and polymer B can be dissolved in an organic solvent, but the upper limit of the difference in SP value is preferably 20 (J / cm ³ ) ^1/2 or less, more preferably 15 (J / Cm ³ ) ^1/2 or less, more preferably 10 (J / cm ³ ) ^1/2 or less.

  Here, the SP value is calculated based on the Fedor's estimation method, and is calculated based on the cohesive energy density and the molar molecular volume (hereinafter also referred to as a calculation method). ("SP Value Basics / Applications and Calculation Methods" by Hideki Yamamoto, Information Organization Co., Ltd., published on March 31, 2005).

  When the calculation cannot be performed by this method, the SP value is calculated by an experimental method by determining whether or not the solubility parameter is dissolved in a known solvent (hereinafter also referred to as an experimental method), and is used. Substitute ("Polymer Handbook Fourth Edition" by J. Brand, published by Wiley in 1998).

  In order to determine whether or not it is in a phase-separated state, after the polymers A and B are adjusted to any polymer A, B and solvent ratio at the temperature and pressure at which the present invention is to be carried out, the polymer A , B are completely dissolved, and after dissolving, the mixture is sufficiently stirred and left for 3 days to confirm whether or not macroscopic phase separation occurs. However, in the case of a sufficiently stable emulsion, macroscopic phase separation may not occur even if left for 3 days. In that case, an optical microscope, a phase contrast microscope, or the like is used to determine whether the phases are microscopically separated.

In the present invention, the interfacial tension between the two phases of the polymer A solution phase and the polymer B solution phase should be directly measured by the hanging drop method in which a different kind of solution is added to a commonly used solution and measured. The interfacial tension can be estimated by estimating from the surface tension of each phase with air. When the surface tension of each phase with air is r ₁ and r ₂ , the interfacial tension r _1/2 can be estimated by the absolute value of r _1/2 = r ₁ −r ₂ .

At this time, a preferable range of r _1/2 is more than 0 to 10 mN / m, more preferably more than 0 to 5 mN / m, still more preferably more than 0 to 3 mN / m, particularly preferably. , More than 0 to 2 mN / m.

  Using the phase-separated system thus obtained, the phase-separated liquid phase is mixed and emulsified, and then polymer fine particles are produced by contacting with a poor solvent.

  In order to make fine particles, a step of forming an emulsion and bringing a poor solvent into contact with each other in a normal reaction vessel (hereinafter sometimes referred to as a fine particle forming step) is performed.

  The fine particles obtained by this production method are fine particles having a very small particle size distribution because they are produced through an emulsion composed of a polymer A solution phase and a polymer B solution phase. For this reason, in order to obtain a sufficient shearing force to form an emulsion, it is sufficient to use stirring by a conventionally known method, such as a liquid phase stirring method using a stirring blade, a stirring method using a continuous biaxial mixer, or a homogenizer. They can be mixed by a generally known method such as a mixing method or ultrasonic irradiation.

  In particular, in the case of stirring with a stirring blade, although depending on the shape of the stirring blade, the stirring speed is preferably 20 rpm to 1,200 rpm, more preferably 30 rpm to 1,000 rpm, still more preferably 30 rpm to 800 rpm, and particularly preferably. Is 50 to 600 rpm.

  Specific examples of the stirring blade include a propeller type, a paddle type, a flat paddle type, a turbine type, a double cone type, a single cone type, a single ribbon type, a double ribbon type, a screw type, and a helical ribbon type. As long as a sufficient shearing force can be applied to the system, it is not particularly limited thereto. Moreover, in order to perform efficient stirring, you may install a baffle plate etc. in a tank.

  In order to generate an emulsion, not only a stirrer but also a widely known device such as an emulsifier and a disperser may be used. Specifically, a batch emulsifier such as a homogenizer (manufactured by IKA), polytron (manufactured by Kinematica), TK auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), Ebara Milder (manufactured by Ebara Seisakusho) , TK fill mix, TK pipeline homomixer (manufactured by Koki Kogyo Co., Ltd.), colloid mill (manufactured by Shinko Pantech Co., Ltd.), slasher, trigonal wet pulverizer (manufactured by Mitsui Miike Chemical Co., Ltd.), ultrasonic homogenizer, static For example, a mixer.

  The emulsion thus obtained is subsequently subjected to a step of precipitating fine particles.

  In order to obtain fine particles of polymer A, the poor solvent for polymer A is brought into contact with the emulsion produced in the above-described step, thereby precipitating fine particles with a diameter corresponding to the emulsion diameter.

  The contact method of the poor solvent and the emulsion may be a method of putting the emulsion in the poor solvent or a method of putting the poor solvent in the emulsion, but a method of putting the poor solvent in the emulsion is preferable.

  In this case, the method for introducing the poor solvent is not particularly limited as long as the polymer fine particles produced in the present invention can be obtained, and any of a continuous dropping method, a divided addition method, and a batch addition method may be used. In order to prevent agglomeration, fusion, and coalescence, particle size distribution, and lump production exceeding 1000 μm, preferably continuous dropping method and divided dropping method, which are industrially efficient. For practical implementation, the continuous dropping method is most preferred.

  The lower limit of the time for adding the poor solvent is preferably 10 minutes or more, more preferably 30 minutes or more, still more preferably 1 hour, and particularly preferably 2 hours or more. Further, the upper limit is preferably within 100 hours, more preferably within 90 hours, still more preferably within 80 hours, and particularly preferably within 50 hours.

  If it is carried out in a time shorter than this range, the particle size distribution may increase or a lump may be generated with the aggregation, fusion, and coalescence of the emulsion. Moreover, when it implements in the time longer than this, when industrial implementation is considered, it is unrealistic.

  The rate of dropping with the poor solvent is preferably as low as possible. In particular, it is important to reduce the speed until 10 parts by mass of the emulsion is added with respect to 100 parts by mass of the total emulsion, so that aggregation of the fine particles can be suppressed and fine sphericity fine particles can be obtained. The amount of the poor solvent dripped per hour is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 8 parts by mass or less with respect to 100 parts by mass of the total emulsion. Yes, particularly preferably 5 parts by mass or less, and most preferably 1 part by mass or less.

  In consideration of industrial implementation, the dropping speed may be changed on the way.

  By contacting with a poor solvent at a dropping rate within this range, when converting from emulsion to polymer fine particles, aggregation between the fine particles can be suppressed, the particle size distribution is small, and the polymer fine particles have high sphericity. Can be obtained.

  The amount of the poor solvent to be added depends on the state of the emulsion, but the lower limit thereof is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, with respect to 100 parts by mass of the total emulsion. More preferably, it is 50 parts by mass or more. Further, the upper limit is preferably 1000 parts by mass or less, more preferably 800 parts by mass or less, still more preferably 500 parts by mass or less, and particularly preferably 250 parts by mass with respect to 100 parts by mass of the total emulsion mass. Part or less, and most preferably 100 parts by weight or less.

  The contact time between the poor solvent and the emulsion may be a time sufficient for the fine particles to precipitate, but in order to cause sufficient precipitation and to obtain efficient productivity, 5 minutes to 50 minutes after completion of the addition of the poor solvent. Time, more preferably 5 minutes or more and 10 hours or less, still more preferably 10 minutes or more and 5 hours or less, particularly preferably 20 minutes or more and 4 hours or less, and most preferably 30 minutes or more and 3 hours or less. Within hours.

  The temperature at which the poor solvent and the emulsion are brought into contact with each other is preferably not higher than the glass transition point of the thermoplastic styrenic elastomer resin.

  Here, the glass transition point means a glass transition point measured by a differential scanning calorimetry (DSC method), and the baseline shifts when the temperature is raised at a rate of temperature increase of 20 ° C./min. The point to do.

  However, the glass transition point of the thermoplastic styrene-based elastomer resin is often -50 ° C. or lower depending on the composition of the thermoplastic styrene-based elastomer resin, and it is difficult to cool it below the glass transition point and make contact with a poor solvent. In that case, it may be higher than the glass transition point. By bringing the poor solvent into contact at a lower temperature, the fusion of the primary particles can be suppressed, the particle size distribution can be further narrowed, and fine particles with higher sphericity can be obtained. Preferably it is 40 degrees C or less, More preferably, it is 20 degrees C or less, More preferably, it is 0 degrees C or less.

  The polymer fine particle dispersion thus prepared is subjected to solid-liquid separation by a generally known method such as filtration, vacuum filtration, pressure filtration, centrifugation, centrifugal filtration, freeze drying, spray drying, etc. Can be recovered.

  The polymer fine particles separated by solid-liquid separation are washed with a solvent or the like, if necessary, to remove impurities attached or contained therein, and then purified.

  In the method of the present invention, it is advantageous that it is possible to perform recycling by reusing the organic solvent and polymer B separated in the solid-liquid separation step performed when obtaining the fine particle powder.

  In this case, in the recycling, it is a requirement for the organic solvent and the polymer B to continue stable production that the change of the substance is suppressed in a series of fine particle production processes.

  The solvent obtained by solid-liquid separation is a mixture of polymer B, an organic solvent and a poor solvent. By removing the poor solvent from this solvent, it can be reused as a solvent for forming an emulsion. The method for removing the poor solvent is usually performed by a known method, and specific examples include simple distillation, vacuum distillation, precision distillation, thin film distillation, extraction, membrane separation, and the like. This is a method by distillation or precision distillation.

  When performing distillation operations such as simple distillation, vacuum distillation, etc., as in the production of polymer fine particles, the system is heated, and there is a possibility of promoting the thermal decomposition of polymer B and organic solvent. It is preferable to carry out in an inert atmosphere. Specifically, it is preferable to carry out under nitrogen, helium, argon, carbon dioxide conditions. Moreover, you may re-add a phenol type compound as antioxidant.

  When recycling, it is preferable to remove the poor solvent as much as possible. Specifically, the residual amount of the poor solvent is preferably 10 parts by mass or less, with respect to 100 parts by mass of the total amount of the organic solvent and polymer B to be recycled. Is 5 parts by mass or less, more preferably 3 parts by mass or less, and particularly preferably 1 part by mass or less. When exceeding this range, the particle size distribution of the fine particles becomes large or the fine particles aggregate, which is not preferable.

  The amount of the poor solvent in the solvent used for recycling can be measured by a generally known method, and can be measured by a gas chromatography method, a Karl Fischer method, or the like.

  In the operation of removing the poor solvent, in reality, the organic solvent, the polymer B, and the like may be lost. Therefore, it is preferable to appropriately adjust the initial composition ratio.

  By producing by such a method, polymer fine particles made of a thermoplastic styrene elastomer having an average particle size of 0.5 μm or more and 100 μm or less and a particle size distribution of less than 3 can be obtained efficiently.

  The thermoplastic styrenic elastomer fine particles of the present invention have a stress relaxation function, and further have excellent dispersibility in the epoxy resin and high stability in the epoxy resin. It is a very effective material as an agent. In order to lower the elastic modulus of the epoxy resin, it is desirable that the thermoplastic styrene-based elastomer fine particles are dispersed as primary particles while maintaining the particle form. In addition, it is desirable that the thermoplastic styrene elastomer fine particles are uniformly dispersed in the epoxy resin, and the more uniformly dispersed, the more uniform the material properties, and the addition of a small amount of the thermoplastic styrene elastomer fine particles makes it efficient. The elastic modulus can be reduced and the internal stress can be relaxed.

  The epoxy resin is not particularly limited. For example, a biphenyl type epoxy resin, a compound having a hydroxyl group in the molecule and a glycidyl ether type epoxy resin obtained from epichlorohydrin, a compound having an amino group in the molecule and epichloro Glycidylamine type epoxy resin obtained from hydrin, glycidyl ester type epoxy resin obtained from epichlorohydrin and compound having carboxyl group in molecule, fat obtained by oxidizing compound having double bond in molecule Cyclic epoxy resins or epoxy resins in which two or more types of groups selected from these are mixed in the molecule are used.

  Specific examples of the glycidyl ether type epoxy resin include bisphenol A type epoxy resin obtained by reaction of bisphenol A and epichlorohydrin, bisphenol F type epoxy resin obtained by reaction of bisphenol F and epichlorohydrin, 4, 4 Bisphenol S-type epoxy resin obtained by reaction of '-dihydroxydiphenylsulfone and epichlorohydrin, biphenyl-type epoxy resin obtained by reaction of 4,4'-biphenol and epochlorohydrin, resorcinol and epichlorohydrin Resorcinol type epoxy resin obtained by reaction, phenol novolak type epoxy resin obtained by reaction of phenol and epichlorohydrin, other polyethylene glycol type epoxy resin, polypropylene glycol Epoxy resins, naphthalene type epoxy resins, and substitutions at these regioisomers and alkyl group or halogen.

  Commercially available bisphenol A type epoxy resins include “jER” (registered trademark) 825, “jER” (registered trademark) 826, “jER” (registered trademark) 827, “jER” (registered trademark) 828 (and above, Mitsubishi). Chemical Co., Ltd.), “Epiclon” (registered trademark) 850 (manufactured by DIC Corporation), “Epototo” (registered trademark) YD-128 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), E. R-331 ™ (Dow Chemical), “Bakelite” EPR154, “Bakelite” EPR162, “Bakelite” EPR172, “Bakelite” EPR173, and Examples thereof include “Bakelite” (registered trademark) EPR174 (manufactured by Bakelite AG).

  Commercially available products of bisphenol F type epoxy resin include “jER” (registered trademark) 806, “jER” (registered trademark) 807, “jER” (registered trademark) 1750 (above, manufactured by Mitsubishi Chemical Corporation), “Epiclon” "(Registered trademark) 830 (manufactured by DIC Corporation)," Epototo "(registered trademark) YD-170," Epototo "(registered trademark) YD-175 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)," Bakelite "(registered) Trademarks) EPR169 (manufactured by Bakelite AG), “Araldite” (registered trademark) GY281, “Araldite” (registered trademark) GY282, “Araldite” (registered trademark) GY285 (above, manufactured by Huntsman Advanced Materials), etc. Is mentioned.

  Commercially available biphenyl type epoxy resins include “jER” (registered trademark) YX4000, “jER” (registered trademark) YX4000K, “jER” (registered trademark) YX4000H, “jER” (registered trademark) YX4000HK, “jER” ( Registered trademark) YL6121H, “jER” (registered trademark) YL6121HN (manufactured by Mitsubishi Chemical Corporation), and the like.

  Examples of commercially available resorcinol-type epoxy resins include “Denacol” (registered trademark) EX-201 (manufactured by Nagase ChemteX Corporation).

  Commercially available phenol novolac epoxy resins include “jER” (registered trademark) 152, “jER” (registered trademark) 154 (manufactured by Mitsubishi Chemical Corporation), “Epicron” (registered trademark) 740 (DIC ( And EPN179, EPN180 (manufactured by Huntsman Advanced Materials), and the like.

  Specific examples of the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethanes, glycidyl compounds of aminophenol, glycidylanilines, and glycidyl compounds of xylenediamine.

  Commercially available tetraglycidyldiaminodiphenylmethanes include “Sumiepoxy” (registered trademark) ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), “Araldite” (registered trademark) MY720, “Araldite” (registered trademark) MY721, “Araldite” ( (Registered trademark) MY9512, “Araldite” (registered trademark) MY9612, “Araldite” (registered trademark) MY9634, “Araldite” (registered trademark) MY9663 (manufactured by Huntsman Advanced Materials), “jER” (registered trademark) 604 (manufactured by Mitsubishi Chemical Corporation), “Bakelite” (registered trademark) EPR494, “Bakelite” (registered trademark) EPR495, “Bakelite” (registered trademark) EPR496, and “Bakelite” (registered trademark) EPR497 (above, akelite AG Co., Ltd.) and the like.

  Commercially available glycidyl compounds of aminophenol include “jER” (registered trademark) 630 (manufactured by Mitsubishi Chemical Corporation), “Araldite” (registered trademark) MY0500, “Araldite” (registered trademark) MY0510 (above Huntsman Advanced Materials Co., Ltd.), “Sumiepoxy” (registered trademark) ELM120, and “Sumiepoxy” (registered trademark) ELM100 (manufactured by Sumitomo Chemical Co., Ltd.).

  Examples of commercially available glycidyl anilines include GAN, GOT (manufactured by Nippon Kayaku Co., Ltd.), “Bakelite” (registered trademark) EPR493 (manufactured by Bakelite AG), and the like.

  Examples of the glycidyl compound of xylenediamine include TETRAD-X (manufactured by Mitsubishi Gas Chemical Co., Inc.).

  Specific examples of the glycidyl ester type epoxy resin include phthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, dimer acid diglycidyl ester and various isomers thereof.

  Examples of commercially available products of diglycidyl phthalate include “Epomic” (registered trademark) R508 (manufactured by Mitsui Chemicals) and “Denacol” (registered trademark) EX-721 (manufactured by Nagase ChemteX Corporation). It is done.

  Examples of commercially available hexahydrophthalic acid diglycidyl ester include “Epomic” R540 (manufactured by Mitsui Chemicals) and AK-601 (manufactured by Nippon Kayaku Co., Ltd.).

  Examples of commercially available dimer acid diglycidyl esters include “jER” (registered trademark) 871 (manufactured by Mitsubishi Chemical Corporation) and “Epototo” (registered trademark) YD-171 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.). It is done.

  Commercially available alicyclic epoxy resins include “Celoxide” (registered trademark) 2021P (manufactured by Daicel Corporation), CY179 (manufactured by Huntsman Advanced Materials), “Celoxide” (registered trademark) 2081 ((stock) ) Manufactured by Daicel), and “Celoxide” (registered trademark) 3000 (manufactured by Daicel Corporation).

  As these epoxy resins, biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin are preferable from the viewpoint of heat resistance, toughness, and low reflow property, more preferably biphenyl type epoxy resin, Bisphenol A type epoxy resin, more preferably biphenyl type epoxy resin. Furthermore, the said epoxy resin can be used by 1 type, or 2 or more types.

  An epoxy resin composition can be obtained by adding an epoxy resin curing agent to the epoxy resin and causing a curing reaction.

  Epoxy resin curing agents include aliphatic polyamines such as diethylenetriamine and triethylenetriamine, alicyclic polyamines such as mensendiamine and isophoronediamine, aromatic polyamines such as diaminodiphenylmethane and m-phenylenediamine, polyamides, modified polyamines, anhydrous Acid anhydrides such as phthalic acid, pyromellitic anhydride and trimellitic anhydride, phenol novolac resin, polymercaptan, 2,4,6-tris (dimethylaminomethyl) phenol, 2-ethyl-4-methylimidazole and 2- Examples include anionic catalysts such as phenyl-4-methylimidazole, cationic catalysts such as boron trifluoride / monoethylamine complex, and latent curing agents such as dicyandiamide, aromatic diazonium salts and molecular sieves.

  Aromatic amine curing agents, acid anhydrides, and phenol novolac resins are preferably used particularly in terms of giving a cured epoxy resin having excellent mechanical properties. Among them, phenol novolac resins are particularly preferable because of excellent storage stability. Is used.

  Specific examples of the aromatic amine curing agent include metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, metaxylylenediamine, diphenyl-p-dianiline, and various derivatives such as alkyl substituents thereof and the position of the amino group. Different isomers are mentioned.

  Specific examples of acid anhydrides include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic acid anhydride, hydrogenated methylnadic acid anhydride, trialkyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, Examples include hexahydrophthalic anhydride, dodecenyl succinic anhydride, and benzophenone tetracarboxylic dianhydride.

  Specific examples of the phenol novolac resin include a phenol aralkyl resin, an o-cresol novolac epoxy resin, a dicyclopentadiene phenol resin, a terpene phenol resin, and a naphthol novolac resin.

  These curing agents can be used alone or in combination of two or more.

  The optimum value of the addition amount varies depending on the type of the epoxy resin and the curing agent, but the stoichiometric equivalent ratio is 0.5 to 1 with respect to the total epoxy groups contained in the epoxy resin composition of the present invention. .4, more preferably 0.6 to 1.4. When the equivalent ratio is less than 0.5, the curing reaction does not occur sufficiently, and curing failure may occur or the curing reaction may take a long time. When the equivalent ratio is larger than 1.4, the curing agent that is not consumed at the time of curing becomes a defect, which may deteriorate the mechanical properties.

  The curing agent can be used in either monomer or oligomer form, and can be in either powder or liquid form when mixed. These curing agents may be used alone or in combination. Moreover, you may use together a hardening accelerator.

  Examples of the curing accelerator include amine compound-based curing accelerators represented by 1,8-diazabicyclo (5.4.0) undecene-7, and imidazoles represented by 2-methylimidazole and 2-ethyl-4-methylimidazole. A compound-based curing accelerator and a phosphorus compound-based curing accelerator represented by triphenyl phosphite are used. Of these, phosphorus compound-based curing accelerators are most preferable.

  In order to advance the curing reaction for obtaining the epoxy resin composition, a temperature may be applied as necessary. The temperature at that time is room temperature to 250 ° C., preferably 50 to 200 ° C., more preferably 70 to It is 190 degreeC, More preferably, it is 100-180 degreeC.

  Moreover, you may apply the temperature raising program as needed. The rate of temperature rise in that case is not particularly limited, but is preferably 0.5 to 20 ° C./min, more preferably 0.5 to 10 ° C./min, and further preferably 1.0 to 5 ° C. / Min.

The pressure during curing, 1~100kg / cm ^2, preferably not 1 to 50 kg / cm ^2, more preferably 1~20kg / cm ^2, more preferably at 1-5 kg / cm ^2.

  You may add an additive to the epoxy resin composition of this invention as needed. Examples of the additive include carbon black, calcium carbonate, titanium oxide, silica, aluminum hydroxide, glass fiber, hindered amine-based and hindered phenol-based degradation inhibitors.

  These are preferably added at the stage before curing, and may be added in any form of powder, liquid or slurry during mixing.

  An epoxy resin composition useful for semiconductor encapsulant application can be obtained by mixing the above-mentioned thermoplastic styrene-based elastomer fine particles in an epoxy resin and / or a curing agent and performing a curing reaction. The polymer fine particles may be added to a mixture in which an epoxy resin and a curing agent are dissolved and mixed in advance.

  The preferable amount of the thermoplastic styrenic elastomer fine particles added to the epoxy resin in the present invention is 0.1 to 50 parts by mass, preferably 0.1 to 40 parts by mass with respect to 100 parts by mass of the epoxy resin. More preferably, it is 0.5-30 mass parts, More preferably, it is 0.5-20 mass parts. By including the thermoplastic styrene-based elastomer fine particles in this range in the epoxy resin, the internal stress can be efficiently relieved in the cured epoxy resin.

  The epoxy resin composition used in the present invention can be prepared by adding the thermoplastic styrenic elastomer fine particles to an epoxy resin and / or a curing agent and kneading them using a generally known kneader. Examples of the kneader include a three-roll kneader, a self-revolving mixer, a planetary mixer, and the like.

  The epoxy resin composition according to the present invention is characterized in that the thermoplastic styrene elastomer fine particles maintain the fine particle shape even after the epoxy resin composition is cured.

  Whether the thermoplastic styrenic elastomer fine particles maintain the fine particle shape in the epoxy resin composition can be determined by confirming the cross section of the cured resin with a photograph obtained with a microscope such as a digital microscope.

  The epoxy resin composition of the present invention is used as a material suitable for a semiconductor encapsulant, because the thermoplastic styrene-based elastomer fine particles dispersed therein function as a stress reducing agent.

  The term “semiconductor sealing material” as used herein refers to a material that seals in order to protect electronic components such as semiconductor elements from external stimuli. In addition to the epoxy resin composition, various additives such as an inorganic filler, a flame retardant, a colorant, and a release agent can be added to the semiconductor encapsulant as necessary.

  The inorganic filler is not particularly limited, and powders and fine particles such as fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, aluminum nitride, boron nitride, beryllia and zirconia are used.

  These inorganic fillers may be used alone or in combination of two or more. Among them, it is preferable to use fused silica because it lowers the linear expansion coefficient. The shape is preferably spherical from the viewpoints of fluidity and wear during molding.

  The blending amount of the inorganic filler is preferably 20 parts by mass to 2000 parts by mass, and more preferably 50 to 2000 parts with respect to 100 parts by mass of the epoxy resin, from the viewpoint of lowering the moisture absorption rate, reducing the linear expansion coefficient, and improving the strength. Parts by mass, more preferably 100 to 2000 parts by mass, particularly preferably 100 to 1000 parts by mass, and most preferably 500 to 800 parts by mass.

  In order to impart flame retardancy, brominated epoxy resin, phosphorus-containing epoxy resin, biphenyl aralkyl type epoxy resin, xanthene skeleton type epoxy resin, polycyclic aromatic epoxy resin, naphthalene type epoxy resin, naphthylene ether skeleton type An epoxy resin, an indole skeleton-type epoxy resin, a polybenzoxazine-type epoxy resin, a siloxane-modified epoxy resin, or the like may be used in combination.

  Although it does not restrict | limit especially as a coloring agent, Carbon black, Bengala, etc. are mentioned.

  The release agent is not particularly limited, and examples thereof include natural waxes such as carbana wax, higher aliphatics such as stearic acid and zinc stearate and metal salts thereof, and paraffin.

  As described above, the polymer fine particles composed of the thermoplastic styrene-based elastomer in the present invention have a characteristic property of low-elasticity fine particles. In addition, it can be applied to various fields such as spacers for liquid crystal displays to prevent damage to substrate materials, additives for toners, additives for paints and adhesives, etc. can do.

  Next, the present invention will be described in more detail based on examples. The present invention is not limited to these examples. In the examples, the measurements used are as follows.

(1) Measurement of number average molecular weight and weight average molecular weight The weight average molecular weight (Mw) and number average molecular weight (Mn) of polymer B are measured by gel permeation chromatography and compared with the calibration curve by polyethylene oxide. Calculated.
Apparatus: Shimadzu Corporation LC-20A Series Column: Showa Denko GF-7MHQ × 2
Flow rate: 1.0 mL / min
Mobile phase: 10 mmol / L Lithium bromide aqueous solution detection: differential refractometer column temperature: 40 ° C.

(2) Calculation method of number average particle diameter, volume average particle diameter, particle diameter distribution index Fine particles were observed and measured with a scanning electron microscope (JEOL Co., Ltd. scanning electron microscope JSM-6301NF). In order to accurately measure the particle size, it is measured at a magnification of at least 300 times, preferably at least 500 times. When the fine particles were not true spheres, the major axis was taken as the particle size, and when the fine particles were overlapped and aggregated, the aggregate was regarded as one fine particle, and the major axis was measured as the particle size.

  The number average particle size (Dn), volume average particle size (Dv), and particle size distribution index (PDI) were calculated according to the following formula from the average of 100 arbitrary fine particles.

  Here, Di: particle diameter of fine particles, n: measurement number 100, Dn: number average particle diameter, Dv: volume average particle diameter, PDI: particle diameter distribution index.

(3) Measurement of bending elastic modulus The epoxy resin composition in which fine particles were dispersed was cut into a width of 10 mm, a length of 80 mm, and a thickness of 4 mm to obtain a test piece. Using a Tensilon universal testing machine (TENSIRON TRG-1250, manufactured by A & D), according to JIS K7171 (2008), a three-point bending test was measured at a distance between fulcrums of 64 mm and a test speed of 2 mm / min. The elastic modulus was measured. The measurement temperature was room temperature (23 ° C.), the number of measurements was n = 5, and the average value was obtained.

  The sample used was manufactured according to the following reference example.

[Reference Example 1] <Sodium acetate washing in polyvinyl alcohol>
In a 1 L eggplant flask, 50 g of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., PVA-1500 weight average molecular weight 29,000, sodium acetate content 0.20% by mass) and 500 mL of methanol are added and stirred at room temperature for 1 hour. did. Then, it separated by suction filtration (filter paper 5A, (phi) 90mm). The same operation was continued twice, and the total operation was repeated three times, followed by drying at 80 ° C. for 10 hours to obtain polyvinyl alcohol having a low sodium acetate content. When the amount of sodium acetate in the obtained polyvinyl alcohol was quantified, it was 0.05% by mass.

[Reference Example 2] <Method for Producing Polyester Elastomer Fine Particles>
In a 1000 mL pressure-resistant glass autoclave (pressure-resistant glass industry, Hyper Glaster TEM-V1000N), polyester elastomer “Hytrel (registered trademark)” 8238 (manufactured by DuPont, weight average molecular weight 27,000) 33.25 g, N -Methyl-2-pyrrolidone 299.25 g, polyvinyl alcohol with a small amount of sodium acetate prepared in Reference Example 1 (manufactured by Wako Pure Chemical Industries, Ltd., PVA-1500, weight average molecular weight 29,000: sodium acetate by washing with methanol The content was reduced to 0.05 mass% or less) 17.5 g was added, and after nitrogen substitution, the mixture was heated to 180 ° C. and stirred for 4 hours until the polymer was dissolved. Thereafter, 350 g of ion-exchanged water as a poor solvent was dropped at a speed of 2.92 g / min via a liquid feed pump. After the entire amount of ion-exchanged water has been added, the temperature is lowered while stirring, and the resulting suspension is filtered, washed with 700 g of ion-exchanged water, reslurried, and filtered off at 80 ° C. for 10 hours. Drying gave 28.3 g of a white solid. When the obtained powder was observed with a scanning electron microscope, it was found to be true spherical fine particles, which were polyester elastomer fine particles having a volume average particle size of 14.7 μm, a particle size distribution index of 1.23, and a sphericity of 97.9. It was.

[Example 1]
In a 200 mL four-necked flask, 2.5 g of styrene-ethylenebutylene copolymer-styrene (SEBS) (manufactured by ALDRICH, weight average molecular weight 118,000, styrene content 30 mass%), tetrahydrofuran 41 as an organic solvent 0.5 g and hydroxypropylcellulose (Tokyo Chemical Industry Co., Ltd., weight average molecular weight 60,000) 6.0 g were added, heated to 40 ° C., and stirred at 450 rpm for 2 hours until the polymer was dissolved. After cooling the system temperature to 0 ° C., the mixture was stirred at 450 rpm to form an emulsion, and 50 g of ethanol as a poor solvent was added dropwise at a speed of 0.14 g / min via a liquid feed pump. After the addition of the entire amount of the poor solvent, the mixture was stirred for 30 minutes, and the resulting suspension was filtered, washed with 100 g of ethanol, and then dried in a vacuum dryer at 50 ° C. for 12 hours to obtain 2.2 g of a white solid. Obtained. When the obtained powder was observed with a scanning electron microscope, it was spherical fine particles and SEBS fine particles having a volume average particle size of 22.5 μm, a particle size distribution index of 2.8, and a sphericity of 70.0.

[Example 2]
In a 200 mL four-necked flask, 2.5 g of styrene-ethylenebutylene copolymer-styrene (SEBS) (manufactured by ALDRICH, weight average molecular weight 118,000, styrene content 30 mass%), tetrahydrofuran 41 as an organic solvent 0.5 g and hydroxypropyl cellulose (Tokyo Chemical Industry Co., Ltd., weight average molecular weight 118,000) 6.0 g were added, heated to 40 ° C., and stirred at 450 rpm for 2 hours until the polymer was dissolved. After cooling the system temperature to −15 ° C. and stirring at 450 rpm to form an emulsion, 50 g of ethanol as a poor solvent was added dropwise at a rate of 0.28 g / min via a liquid feed pump. After the addition of the entire amount of the poor solvent, the mixture was stirred for 30 minutes, and the resulting suspension was filtered, washed with 100 g of ethanol, and then dried in a vacuum dryer at 50 ° C. for 12 hours to obtain 2.1 g of a white solid. Obtained. When the obtained powder was observed with a scanning electron microscope, it was spherical fine particles, SEBS fine particles having a volume average particle size of 8.71 μm, a particle size distribution index of 1.58, and a sphericity of 84.5.

[Example 3]
In a 200 mL four-necked flask, 2.5 g of styrene-ethylenebutylene copolymer-styrene (SEBS) (manufactured by ALDRICH, weight average molecular weight 118,000, styrene content 30 mass%), tetrahydrofuran 41 as an organic solvent 0.5 g and hydroxypropylcellulose (Tokyo Chemical Industry Co., Ltd., weight average molecular weight 60,000) 6.0 g were added, heated to 40 ° C., and stirred at 450 rpm for 2 hours until the polymer was dissolved. Subsequently, 125 g of water as a poor solvent was dropped for 48 hours at a speed of 0.25 g / hour via a liquid feed pump, and then the speed was changed at 25 g / hour and dropped. After the addition of the entire amount of the poor solvent, the mixture was stirred for 30 minutes, and the resulting suspension was filtered, washed with 100 g of water, and then dried in a vacuum dryer at 50 ° C. for 12 hours to obtain 2.1 g of a white solid. Obtained. When the obtained powder was observed with a scanning electron microscope, it was spherical fine particles and SEBS fine particles having a volume average particle size of 75.8 μm, a particle size distribution index of 2.67, and a sphericity of 81.9.

[ Comparative Example 5 ]
In a 200 mL four-necked flask, styrene-ethylenepropylene copolymer-styrene (SEPS) (Kuraray Co., Ltd., “SEPTON (registered trademark)” 2002, styrene content 3
0% by weight) 2.5 g, 46.5 g diethylene glycol dimethyl ether as organic solvent
Hydroxypropyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd., weight average molecular weight 118,0
00) 1.0 g, and heated to 95 ° C. and 450 rpm for 2 hours until the polymer is dissolved
Was stirred. Subsequently, after cooling to 30 ° C. and stirring at 450 rpm for 30 minutes, 50 g of ethanol as a poor solvent was passed through a liquid feed pump at a speed of 0.14 g / hour.
Dropped for hours. After the addition of the entire amount of the poor solvent, the mixture was stirred for 30 minutes, and the resulting suspension was filtered, washed with 100 g of ethanol, and then dried in a vacuum dryer at 50 ° C. for 12 hours to obtain 2.1 g of a white solid. Obtained. When the obtained powder was observed with a scanning electron microscope, it was spherical fine particles, SEB having a volume average particle size of 96.4 μm, a particle size distribution index of 1.87, and a sphericity of 57.7.
S fine particles.

[Example 5]
A 150cc stainless beaker containing 38.25g of biphenyl type epoxy resin ("jER" (registered trademark) YX4000H manufactured by Mitsubishi Chemical Corporation) and 21.75g of phenol resin type curing agent (manufactured by Meiwa Kasei Co., Ltd., H-1). Was dissolved in an oven at 120 ° C. and homogenized. To the obtained epoxy resin composition, 8.00 g of SEBS fine particles obtained in Example 1 (15% by volume with respect to the total amount of the epoxy resin composition), tetraphenylphosphonium tetra-p-tolylborate as a curing accelerator was added. 3 g was added and mixed easily with a stir bar, and then mixed at 2000 rpm, 80 kPa, 1.5 minutes, 2000 rpm, 50 kPa, 1. Stirring for 5 minutes was performed once and stirring was performed twice at 2000 rpm and 0.2 kPa for 1.5 minutes to obtain an uncured epoxy resin composition. This uncured epoxy resin composition was cast into an aluminum mold in which a 4 mm-thick “Teflon” (registered trademark) spacer and release film were set, and placed in an oven. The oven temperature was set to 80 ° C., held for 5 minutes, then heated to 175 ° C. at a heating rate of 1.5 ° C./min and cured for 4 hours to obtain a 4 mm thick epoxy resin composition. The resulting cured epoxy resin was cut into a width of 10 mm and a length of 80 mm, and bent at 3 points according to JIS K7171 (2008) using a Tensilon universal testing machine (TENSIRON TRG-1250, manufactured by A & D). It was 2.1 GPa when the test was measured and the bending elastic modulus was measured.

[Comparative Example 1]
In a 200 mL four-necked flask, 18.0 g of styrene-ethylenebutylene copolymer-styrene (SEBS) (manufactured by ALDRICH, weight average molecular weight 18,000, styrene content 30 mass%) and 102.0 g of xylene Weighed and heated at 50 ° C. for 1 hour with stirring at 250 rpm to obtain a uniform polymer solution. In addition, 2.0 g of Piionin B-231 (manufactured by Takemoto Yushi Co., Ltd., 50% aqueous solution of palm alkyldimethylbenzylammonium chloride) was dissolved in 28.0 g of water and then added to the polymer solution. The resulting solution was stirred for 2 minutes at 10,000 rpm using a homogenizer in a 300 mL beaker to prepare an emulsion. Thereafter, xylene was removed using an evaporator and dried at room temperature for 24 hours. However, the particles were fused together to form a lump, and no usable powder was obtained.

[Comparative Example 2]
In a 200 mL four-necked flask, 2.5 g of styrene-ethylenebutylene copolymer-styrene (SEBS) (manufactured by ALDRICH, weight average molecular weight 118,000, styrene content 30% by mass), 45 g of tetrahydrofuran as an organic solvent And 2.5 g of hydroxypropyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd., weight average molecular weight 60,000) were added, heated to 40 ° C., and stirred at 450 rpm for 2 hours until the polymer was dissolved. Then, after stirring at 450 rpm to form an emulsion, 50 g of water as a poor solvent was dropped at a speed of 0.42 g / min via a liquid feed pump. After the addition of the entire amount of the poor solvent, the mixture was stirred for 30 minutes, and the resulting suspension was filtered, washed with 100 g of ethanol, and then dried in a vacuum dryer at 50 ° C. for 12 hours to obtain 2.2 g of a white solid. Obtained. When the obtained powder was observed with a scanning electron microscope, it was SEBS fine particles having a volume average particle size of 135.8 μm, a particle size distribution index of 32, and a sphericity of 55.

[Comparative Example 3]
An epoxy resin composition was prepared in the same manner as in Example 2 except that the polymer fine particles were not added. It was 2.9 GPa when the three-point bending test was measured using the obtained epoxy resin hardened | cured material and the bending elastic modulus was measured.

[Comparative Example 4]
An epoxy resin composition was prepared in the same manner as in Example 2 except that the polymer fine particles to be added were 9.75 g of polyester elastomer fine particles obtained in Reference Example 2 (15% by volume with respect to the total amount of the epoxy resin composition). When the cross section of the obtained epoxy cured product was observed with an optical microscope, the polyester elastomer fine particles were dissolved in the epoxy resin, and the particle morphology was not maintained. Moreover, it was 2.8 GPa when the three-point bending test was measured using the obtained epoxy resin hardened | cured material and the bending elastic modulus was measured.

Claims (7)

A thermoplastic styrene elastomer characterized by being a styrene-ethylenebutylene copolymer and a block copolymer of styrene, having an average particle size of 0.5 μm or more and 100 μm or less, and a particle size distribution index of less than 3 Polymer fine particles characterized in that 2. The fine polymer particle according to claim 1, wherein the average particle size is more than 1 μm and 100 μm or less. 3. The fine polymer particle according to claim 1, wherein the sphericity is 80 or more. The polymer fine particle according to any one of claims 1 to 3, wherein a salt containing an alkali metal and an alkaline earth metal contained in the polymer fine particle is 1% by mass or less. Epoxy resin composition comprising an epoxy resin and claim 1 polymer microparticles according to any one of 4. The epoxy resin composition according to claim 5, comprising 0.1 to 50 parts by mass of the polymer fine particles according to any one of claims 1 to 4 with respect to 100 parts by mass of the epoxy resin. The semiconductor sealing material which consists of an epoxy resin composition of Claim 5 or 6 .