JP2019196462A - Method for producing particle used as constituent component of sealing epoxy resin composition, core-shell particle used as constituent component of sealing epoxy resin composition and sealing epoxy resin composition - Google Patents

Abstract

To improve the homogeneity of particles in the production of the particles used as a constituent component of a sealing epoxy resin composition.SOLUTION: There is provided a method for producing particles used as a constituent component of a sealing epoxy resin composition which comprises: (1) a melting and mixing step of obtaining a molten mixture (A) of en epoxy resin and a curing agent; (2) a feeding step of feeding the molten mixture (A) obtained in the melting and mixing step, an inorganic filler (B) and at least one material selected from the group consisting of a coloring agent and an ion scavenger in a stirring device equipped with a stirring blade; and (3) after the feeding step, a granulation step of heating the components fed in the stirring device to 110°C or more while driving the stirring blade at the linear velocity of 0.1 m/s or more at the tip to mix to obtain core-shell particles having a shell containing the molten mixture (A) outside a core containing the inorganic filler (B) and the material (C).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing particles used as a constituent of an epoxy resin composition for sealing, a core-shell particle used as a constituent of an epoxy resin composition for sealing, and an epoxy resin composition for sealing.

Semiconductor devices are mainly sealed using an epoxy resin composition for sealing. With the downsizing, thinning, and complicated structure of semiconductor devices, development of epoxy resin compositions for sealing has been continued.
In the development of an epoxy resin composition for sealing, not only the composition of the composition but also the production method has been actively studied.

For example, Patent Document 1 describes a manufacturing method for efficiently supplying an epoxy resin molding material for granular semiconductor encapsulation with a small amount of fine particles.
Specifically, a granular composition formed by blending, kneading, cooling and pulverizing each component such as an epoxy resin is heated by radiant heat while being supplied to a stirring vessel equipped with a stirring blade and stirred. Thus, it is described that a granular epoxy resin molding material is produced.

  Patent Document 2 discloses a granular semiconductor encapsulant characterized by adding a specific siloxane compound to a pulverized product obtained by kneading a resin component and an inorganic filler and then granulating it. A method of manufacturing the stop material is described.

JP 2000-280237 A JP 2000-129139 A

As shown in Patent Documents 1 and 2 above, in the production of an epoxy resin composition for sealing or an intermediate raw material thereof, the raw material components are often kneaded or the raw material components are granulated.
It can be easily imagined that the performance of the resulting epoxy resin composition for sealing or an intermediate raw material thereof changes depending on the skill of specific methods of kneading and granulation. It goes without saying that it is industrially important to obtain a stable and homogeneous epoxy resin composition for sealing or an intermediate raw material thereof.
However, according to the knowledge of the present inventor, with regard to obtaining a homogeneous sealing epoxy resin composition or an intermediate raw material thereof (specifically, particles used as a constituent component of the sealing epoxy resin composition) There was still room for improvement.

  The present invention has been made in view of such circumstances. An object of the present invention is to improve the homogeneity of particles used in the production of particles used as a constituent component of an epoxy resin composition for sealing.

  As a result of the study, the inventors of the present invention focused on the mixing process conditions when granulating by heating while mixing each component in the method for producing particles used as a constituent component of the epoxy resin composition for sealing. As a result, the invention provided below was completed. And it discovered that the said subject could be achieved.

According to the present invention,
A method for producing particles used as a constituent of an epoxy resin composition for sealing,
A melt mixing step for obtaining a melt mixture (A) of an epoxy resin and a curing agent;
A charging step of charging the molten mixture (A), the inorganic filler (B), and at least one material (C) selected from the group consisting of a colorant and an ion scavenger into a stirrer equipped with a stirring blade. When,
After the charging step, the components charged in the stirrer are heated to 110 ° C. or higher by mixing and driving the stirring blade at a linear velocity of 0.1 m / s or more at the tip, and the inorganic There is provided a method for producing particles including a core shell particle having a shell containing the molten mixture (A) outside a core containing a filler (B) and the material (C).

Moreover, according to the present invention,
For sealing, provided with a shell containing an epoxy resin and a curing agent on the outside of a core containing an inorganic filler (B) and at least one material (C) selected from the group consisting of a colorant and an ion scavenger Core-shell particles used as a constituent of an epoxy resin composition are provided.

According to the present invention, when producing particles used as a constituent component of an epoxy resin composition for sealing, the homogeneity of the particles can be improved.
Note that “particles are homogeneous” means, for example, that when the particles are core-shell particles, the thickness of the shell is substantially uniform and / or the particle size distribution is relatively narrow.

It is a figure (sectional view of a stirring device) which shows an example of a stirring device typically. It is a figure (cross-sectional view of a stirring apparatus) which shows another example of a stirring apparatus typically.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings, the same components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
In order to avoid complications, (i) when there are a plurality of identical components in the same drawing, only one of them is given a reference, and all are not attached, or (ii) 2 and later, the same components as in FIG. 1 may not be denoted again.
All drawings are for illustrative purposes only. The shape and dimensional ratio of each member in the drawings do not necessarily correspond to an actual article.

In this specification, the term “substantially” means that it includes a range that takes into account manufacturing tolerances, assembly variations, and the like, unless otherwise specified.
In the present specification, the notation “ab” in the description of the numerical range represents a range from a to b unless otherwise specified. For example, “1 to 5% by mass” means “1 to 5% by mass”.

In the notation of a group (atomic group) in this specification, the notation which does not describe substitution or non-substitution includes both those having no substituent and those having a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
The notation “(meth) acryl” in the present specification represents a concept including both acrylic and methacrylic. The same applies to similar notations such as “(meth) acrylate”.
In this specification, the term “electronic device” means an element to which an electronic technology is applied, such as a semiconductor chip, a semiconductor element, a printed wiring board, an electric circuit display device, an information communication terminal, a light emitting diode, a physical battery, and a chemical battery. , Device, final product and the like.

Unless otherwise specified, the “particle size” of various particles in the present specification is determined by, for example, a laser diffraction / scattering particle size distribution measuring device (for example, a wet particle size distribution measuring device LA-950 manufactured by Horiba, Ltd.). It can be obtained by acquiring volume-based particle size distribution data and processing the data.
For example, the “average particle size” can be obtained by arithmetic average of the obtained particle size distribution data. Further, from the particle size distribution data, a cumulative 10% value (D10), a cumulative 50% value (median diameter, D50), a cumulative 90% value (D90), and the like can be obtained.

<Method for producing particles>
The method for producing particles of the present embodiment is a method for producing particles (core-shell particles) used as a constituent component of the sealing epoxy resin composition. And
A melt mixing step for obtaining a melt mixture (A) of an epoxy resin and a curing agent;
A charging step of charging the molten mixture (A), the inorganic filler (B), and at least one material (C) selected from the group consisting of a colorant and an ion scavenger into a stirrer equipped with a stirring blade. When,
After the charging step, the components charged into the stirring device are heated while being mixed by driving the stirring blade at a linear velocity of 0.1 m / s or more at the tip, and the temperature is set to 110 ° C. or higher. And B) and a granulation step of obtaining core-shell particles having a shell containing the molten mixture (A) outside the core containing the material (C).

  Although the detailed mechanism is unknown, in the granulation process, the molten mixture (A) moderately softened at a temperature of 110 ° C. or higher is subjected to a large shearing force due to stirring (rotation of the stirring blade) at a constant speed or higher. Therefore, it is considered that the surface of the core containing the inorganic filler (B) and the material (C) is easily thinly and uniformly coated. And it is thought that the core-shell particle | grains with the substantially uniform thickness of a shell are obtained.

  Further, the inorganic filler (B) and the material (C) are appropriately mixed by a large shearing force by stirring at a constant speed or higher. As a result, a shell of the molten mixture can be formed around the core containing “both” of the inorganic filler (B) and the material (C). That is, when core-shell particles are manufactured by the particle manufacturing method of the present embodiment, it is considered that the components of the epoxy resin composition for sealing can be easily included in one particle. This is preferable from the viewpoint of not only the homogeneity of the particles but also the homogeneity of the distribution of the components.

  Each process described above, materials used in each process, processes that may optionally be included, and the like will be described.

(Melting and mixing process)
In the melt mixing step, an epoxy resin and a curing agent are used to obtain these melt mixtures (A) by an appropriate method.
The method of melt mixing is not particularly limited. For example, (1) First, an epoxy resin and a curing agent are put in a suitable container (a container that can be heated and mixed, such as a heating pot), (2) next, they are heated and mixed, and (3) are then cooled and pulverized. The molten mixture (A) which is a pulverized product (granular or particulate) can be obtained by a three-stage method through the above. In addition, you may pre-mix before (1).

In the heating and mixing in (2) above, for example, a jacket is provided in a heating kettle to circulate the heat medium oil, and a stirrer with a stirring blade is used, for example, at 120 to 180 ° C. for 1 to 60 minutes. It can be carried out.
In the cooling and pulverizing step (3), for example, the mixture obtained in (2) is cooled to 40 ° C. or lower (preferably 10 ° C. or lower), and then a known pulverizer (granulator) is used. Can be done. In addition, you may perform the process (For example, the classification process using a sieve etc.) which arranges a particle size except a coarse particle and a particle | grain too fine after a grinding | pulverization process.

  The average particle size of the molten mixture (A) which is a pulverized product (granular or particulate) is preferably 5 mm or less, more preferably 0.1 to 2 mm. By making the average particle size of the molten mixture (A) small to some extent, it tends to make the shell thickness more uniform in the granulation step described later.

The epoxy resin that can be used in the melt mixing step is not particularly limited, and for example, a known epoxy resin in the field of the epoxy resin composition for sealing can be used. That is, as the epoxy resin, monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule can be used, and the molecular weight and molecular structure are not particularly limited.
About an epoxy resin, only 1 type may be used and 2 or more types may be used together.

  Specific examples of epoxy resins include biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, stilbene type epoxy resins, hydroquinone type epoxy resins and the like; cresol novolac type epoxy resins, phenol novolak type Novolak type epoxy resins such as epoxy resins and naphthol novolak type epoxy resins; Phenol aralkyl type epoxy resins such as phenylene skeleton-containing phenol aralkyl type epoxy resins, biphenylene skeleton containing phenol aralkyl type epoxy resins, phenylene skeleton containing naphthol aralkyl type epoxy resins; Trifunctional epoxy resins such as phenol methane type epoxy resin and alkyl-modified triphenol methane type epoxy resin; dicyclopentadiene modification Phenol epoxy resins, modified phenol type epoxy resins such as terpene-modified phenol type epoxy resins; heterocycle-containing epoxy resins such as triazine nucleus-containing epoxy resins.

The curing agent that can be used in the melt mixing step is not particularly limited, and for example, a known curing agent in the field of the epoxy resin composition for sealing can be used. The curing agent is not particularly limited as long as it reacts with the epoxy resin and cures the epoxy resin.
About a hardening | curing agent, only 1 type may be used and 2 or more types may be used together.

Specific examples of the curing agent include amine-based curing agents (curing agents having amino groups) and phenol-based curing agents.
Examples of amine curing agents include linear aliphatic diamines having 2 to 20 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, metaphenylenediamine, paraphenylenediamine, paraxylenediamine, 4,4 ′. -Diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodicyclohexane, bis (4-aminophenyl) phenylmethane, , 5-diaminonaphthalene, metaxylenediamine, paraxylenediamine, 1,1-bis (4-aminophenyl) cyclohexane, dicyanodiamide and the like.
Examples of the phenolic curing agent include resol type phenol resins such as aniline-modified resole resin and dimethyl ether resole resin; Examples thereof include phenol aralkyl resins such as aralkyl resins and biphenylene skeleton-containing phenol aralkyl resins; phenol resins having a condensed polycyclic structure such as naphthalene skeleton and anthracene skeleton.

  Other curing agents include polyoxystyrenes such as polyparaoxystyrene; alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), trimellitic anhydride (TMA), pyro anhydride Acid anhydrides including aromatic acid anhydrides such as merit acid (PMDA) and benzophenone tetracarboxylic acid (BTDA); polymercaptan compounds such as polysulfide, thioester, thioether; isocyanate compounds such as isocyanate prepolymer and blocked isocyanate An organic acid such as a carboxylic acid-containing polyester resin.

  Of these, the curing agent used for the semiconductor sealing material is preferably a compound having at least two phenolic hydroxyl groups in one molecule from the viewpoint of moisture resistance, reliability, and the like. More specifically, phenol novolac resin, cresol novolak resin, tert-butylphenol novolak resin, novolak type phenol resin such as nonylphenol novolak resin; resol type phenol resin; polyoxystyrene such as polyparaoxystyrene; phenylene skeleton-containing phenol aralkyl resin Preferred examples include biphenylene skeleton-containing phenol aralkyl resins.

The mixing ratio (mass ratio) of the epoxy resin and the curing agent in the melt mixing step is not particularly limited, but preferably, when the total amount of the epoxy resin and the curing agent is 100 parts by mass, the epoxy resin is 50 to 90 masses. Parts, and a ratio of 10 to 50 parts by mass of the curing agent.
By appropriately adjusting the mixing ratio of the epoxy resin and the curing agent, it can be considered that the shell of the molten mixture is more uniformly coated on the outside of the core in the granulation step described later. Moreover, it is thought that the performance as the sealing material itself of the epoxy resin composition for sealing using the core-shell particle finally obtained can be improved.

In the melt mixing step, at least an epoxy resin and a curing agent are used as raw materials to obtain a molten mixture (A), but other raw materials may be additionally used.
Additional raw materials that can be used include, for example, coupling agents (silane coupling agents, etc.), mold release agents (natural waxes, synthetic waxes, higher fatty acids or their metal salts, paraffin, polyethylene oxide, etc.), and low stress agents. (Silicone oil, silicone rubber, etc.).
When these raw materials are used, the amount thereof can be, for example, about 0.1 to 10 parts by mass when the total amount of the epoxy resin and the curing agent is 100 parts by mass.

  In addition, from the viewpoints of suppressing deterioration of raw materials and stability over time, the molten mixture (A) preferably does not contain a curing catalyst (an epoxy resin curing catalyst).

(Input process)
In the charging step, at least one material (C) selected from the group consisting of the above-mentioned molten mixture (A), inorganic filler (B), colorant and ion scavenger is provided with a stirring blade. Into the stirring device. In addition to these, a flame retardant (such as aluminum hydroxide) or an antioxidant may be added in addition.
Hereinafter, at least one material (C) selected from the group consisting of a colorant and an ion scavenger is also simply referred to as “material (C)”.

  A stirrer equipped with a stirring blade (hereinafter also simply referred to as “stirring device”) is a stirring blade (often referred to as “stirring blade”) that can stir the molten mixture (A), the inorganic filler (B), and the material (C). Provided that the linear velocity at the tip of the blade can be made 0.1 m / s or more when the stirring blade is driven (the linear velocity at the tip of the blade). Will be detailed later). In addition, since it may reduce pressure in the granulation process mentioned later, it is preferable that the stirring apparatus can be stirred under reduced pressure.

About a stirring apparatus, FIG.1, FIG.2 (i), FIG.2 (ii) etc. can be shown, for example. These drawings are diagrams (cross-sectional views) schematically showing examples of the stirring device.
The stirring device 1 includes a stirring blade 2, a shaft 3, and a tank body 4. Although not shown, a motor for rotating the stirring blade 2 and the shaft 3, a speed reducer for reducing the rotation of the motor to a rotation speed suitable for stirring, a lid for stirring in a sealed state, Equipment for pressurization, equipment for temperature control (heater, cooling device, thermometer, etc.), and other necessary equipment can be provided.

  The shape of the stirring blade 2 is not limited to the shape shown in FIGS. 1, 2 (i) and 2 (ii), but an anchor shape, a helical ribbon shape, a propeller shape, a disk turbine shape, an inclined paddle shape, Various types known in the field of stirring devices such as an edged turbine shape can be used.

The inorganic filler (B) that can be used in the charging step is not particularly limited. For example, a well-known inorganic filler can be used in the field of the epoxy resin composition for sealing.
Specific examples of the inorganic filler (B) include fused crushed silica, fused spherical silica, crystalline silica, secondary agglomerated silica and the like; alumina; titanium white; aluminum hydroxide; talc; clay; mica; Can be mentioned. Among these, fused spherical silica is particularly preferable.
The particle shape of the inorganic filler (B) is preferably substantially spherical.
The average particle diameter of the inorganic filler (B) is not particularly limited, but is typically 1 to 100 μm, preferably 1 to 50 μm, more preferably 1 to 20 μm. When the average particle size is appropriate, it is considered that an effect such as more uniform coating of the shell containing the molten mixture (A) is obtained in the granulation step described later. In addition, when the finally obtained core-shell particles are used as a semiconductor sealing material, the filling property around the semiconductor element in the mold cavity can be improved.

The colorant that can be used in the charging step is not particularly limited. For example, carbon black can be used. When using a coloring agent, only 1 type may be used and 2 or more types may be used together.
There are no particular limitations on the ion scavenger (also referred to as ion catcher, ion trap agent, etc.) that can be used in the charging step. For example, hydrotalcite can be used. Bismuth oxide and yttrium oxide are also known as ion scavengers. When using an ion scavenger, only 1 type may be used and 2 or more types may be used together.

Flame retardants that can be used in the charging process are not particularly limited, and include inorganic flame retardants (for example, hydrated metal compounds such as aluminum hydroxide), halogen flame retardants, phosphorus flame retardants, and organic metal salt flame retardants. Can be mentioned. When using a flame retardant, only 1 type may be used and 2 or more types may be used together.
Antioxidants that can be used in the charging process are not particularly limited. For example, phenolic antioxidants (dibutylhydroxytoluene, etc.), sulfur antioxidants (mercaptopropionic acid derivatives, etc.), phosphorus antioxidants (9, 9) 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide etc.). When using antioxidant, only 1 type may be used and 2 or more types may be used together.

  By adjusting the quantity ratio of the molten mixture (A), the inorganic filler (B), and the material (C) to be introduced into the apparatus in the charging step, the uniformity of the particles (such as the uniformity of the shell thickness) Can be further enhanced.

For example, the ratio of the molten mixture (A) in all components charged into the stirring device 1 in the charging step is preferably 15% by mass or less, more preferably 0.1 to 10% by mass, and still more preferably 0.1 to 10% by mass. By setting the content to 5% by mass, the uniformity of the particles (such as uniformity of the thickness of the shell) can be further enhanced.
The amount of the inorganic filler (B) to be charged is preferably 85 to 99.9% by mass in all the components charged into the stirring device 1 in the charging step.
The amount of the material (C) to be added is preferably 0.1 to 3% by mass, and more preferably 0.1 to 1% by mass in all the components to be added to the stirring device 1 in the charging step.

(Granulation process)
In the granulation step after the charging step, the components charged into the stirring device 1 in the charging step are heated to 110 ° C. or higher while being mixed by driving the stirring blade 2. This temperature is preferably 110 to 180 ° C, more preferably 120 to 170 ° C. When the temperature is 110 ° C. or higher, the molten mixture (A) is appropriately softened, and it becomes easy to coat a uniform shell. Moreover, deterioration of a raw material is suppressed because temperature is 180 degrees C or less, and the performance of the core-shell particle finally obtained and the epoxy resin composition for sealing using the same can be improved more.
As a precaution, “the component charged into the stirring device 1 in the charging step is set to 110 ° C. or higher” means that the component itself (finally granulated in the charging step). The component itself) is 110 ° C. or higher. This can be confirmed, for example, by temporarily interrupting the granulation step and measuring the temperature of the contents in the stirring device 1. Or you may confirm by using a thing with a viewing window as the stirring apparatus 1, and measuring temperature with the radiation thermometer from the viewing window.

  In the granulation step, the shaft 3 and the stirring blade 2 are rotated at a somewhat large rotational speed so that the linear velocity at the tip of the stirring blade 2 is 0.1 m / s or higher. Thereby, the moderately softened molten mixture (A) receives a large shearing force by stirring at a high speed. And it is thought that the core-shell particle | grains provided with the shell (thickness is substantially uniform) containing the molten mixture (A) in the outer side of the core containing an inorganic filler (B) and material (C) are considered. Also, due to the large shearing force, the inorganic filler (B) and the material (C) are moderately mixed, and as a result, the molten material is melted around the core containing “both” of the inorganic filler (B) and the material (C). It is believed that a shell of the mixture can be formed.

It supplements about "the front-end | tip of the stirring blade 2."
The tip of the stirring blade 2 is typically a portion having the longest moving distance per unit time when the stirring blade 2 rotates. In other words, it can be expressed as a portion that moves fastest when the stirring blade 2 rotates (a portion that exhibits the fastest linear velocity).
In the stirring blade 2 in FIG. 1, both ends (right end and left end portions) are “tips”.
In the case of FIG. 2 (i), there are three stirring blades 2 in the form, but the tip of the lowest stirring blade 2 in the figure corresponding to the “tip of the stirring blade 2” has the largest rotation radius. To do.
In the case of FIG. 2 (ii), the agitating blade 2 shown in the figure has five protrusions symmetrically with respect to the axis 3, and of these, the lowermost protrusion The tip (the travel distance is the largest when rotated) corresponds to the “tip of the stirring blade 2”.

In addition, a supplementary explanation will be given for the “linear velocity at the tip of the stirring blade 2”.
The linear velocity at the tip of the stirring blade 2 typically means the maximum value of the relative speed of the tip of the stirring blade 2 with respect to the tank body 4 (the tank body 4 is normally fixed).
When there is only one rotating shaft, the value obtained by the equation of πND / 60, where D (m) is the diameter (rotating diameter) of the stirring blade 2 and N (rpm) is the rotational speed of the stirring blade 2 The tip linear velocity (m / s) is obtained. Here, π is the circumference ratio.
For example, when a stirring blade rotates and revolves like a planetary mixer, the linear velocity at the tip of the blade cannot be obtained by the above simple formula, but the rotation speed and the revolving speed are appropriately combined. For example, the maximum value of the relative speed at the tip of the stirring blade may be obtained. Alternatively, the linear velocity at the blade tip may be obtained by actual measurement instead of calculation. For example, it may be obtained by analyzing the moving image by driving the stirrer 1 without adding a material and shooting the motion of the blade tip.

  The linear velocity at the tip of the stirring blade 2 may be 0.1 m / s or more, preferably 0.4 m / s or more, and more preferably 1.0 m / s or more. The upper limit of the linear velocity is not particularly limited, but is preferably 10 m / s or less, more preferably 8 m / s or less, and still more preferably 5 m / s or less, from the viewpoint of apparatus limitations.

There is usually a clearance (clearance) between the tip of the stirring blade 2 and the tank body 4. In FIG. 1, FIG. 2 (i), and FIG. 2 (ii), the magnitude | size of this clearance is specified as a. Although details are unknown, it is presumed that due to the appropriate clearance, the components colliding with the stirring blade 2 escape to the clearance appropriately during the granulation step, which further promotes the granulation. Thereby, it is considered that the particle size distribution of the particles can be made more uniform.
Specifically, the size of the clearance is preferably 0.5 to 10 mm, more preferably 1 to 8 mm.

  In the granulation step, the time when the component charged in the stirring device 1 is 110 ° C. or higher (the time for keeping the component at 110 ° C. or higher) is preferably 5 to 200 minutes, more preferably 10 to 180 minutes, Preferably it is 20 to 150 minutes. By setting this time to 10 minutes or more, it is easy to form a sufficiently thick shell, and the shell thickness can be made more uniform. Moreover, deterioration of a raw material etc. can be suppressed by making this time into 200 minutes or less. Therefore, when this core-shell particle is applied to the epoxy resin composition for sealing, various performances can be further improved.

Part or all of the granulation step is preferably performed under reduced pressure. Specifically, part or all of the granulation step is preferably under a reduced pressure of 30 kPa or less, more preferably under a reduced pressure of 0.01 to 20 kPa, even more preferably under a reduced pressure of 0.05 to 15 kPa, particularly preferably. It is performed under a reduced pressure of 0.1 to 10 kPa.
The granulation process can be performed under reduced pressure by using, for example, the stirring device 1 capable of reducing the pressure during stirring.
The decompression is preferably performed for at least half of the total time of the granulation step.

It is considered that the moisture contained in the components charged into the stirring device 1 is further reduced by performing part or all of the granulation step under reduced pressure. More specifically, it is considered that much of the water adhering to the charged inorganic filler (B) and the like is removed by reducing the pressure (and heating at 110 ° C. or higher). Thereby, it is considered that a situation in which the molten mixture (A) is hardened only on a part of the core of the inorganic filler (B) or the material (C) is further suppressed, and a shell having a more uniform thickness can be formed.
In particular, when the inorganic filler (B) is silica, it is considered that water removal by reduced pressure (degassing) is preferable because silica easily adsorbs water due to its properties.

  As a precaution, in the granulation step, the charged components are heated at 110 ° C. or higher, so that some moisture is removed without reducing the pressure. That is, decompression is not essential in the granulation process. However, it is preferable to perform pressure reduction from the viewpoint of further reducing moisture.

In addition, from the viewpoint of “removing moisture”, a moisture reducing step for reducing moisture contained in the inorganic filler (B) or the like may be provided. The above “reduced pressure” may correspond to this moisture removal step, but the moisture contained in the inorganic filler (B) or the like may be reduced by a method different from the reduced pressure.
For example, it may be possible to heat the inorganic filler (B) or, in some cases, the material (C), etc. before the charging step to sufficiently dry the water before charging. Further, before the charging step, the inorganic filler (B), the material (C) and the like may be deaerated to reduce the attached moisture.
However, from the viewpoint of simplification of the manufacturing process and cost reduction, it is preferable to reduce moisture by reducing the pressure in the granulation process.

(Cooling and stirring process)
The method for producing particles according to the present embodiment preferably includes a cooling and stirring step of cooling the stirring blade 2 while stirring the components in the stirring device after the granulation step. Thereby, it is further preferable that the core-shell particles obtained in the granulation step described above are further suppressed from agglomerating (becomes agglomerated) during cooling.

Although the speed which rotates the stirring blade 2 in a cooling stirring process is not specifically limited, As linear velocity of the front-end | tip of the stirring blade 2, it is 0.01-10 m / s, Preferably it is the range of 0.1-5 m / s. It can be set appropriately.
The time of the cooling and stirring step is not particularly limited and can be set as appropriate. For example, it is 10 to 200 minutes, preferably 20 to 180 minutes, more preferably 30 to 150 minutes.

  The core-shell particles are preferably cooled to a temperature not higher than the softening point of the molten mixture (A) by the cooling and stirring step. Typically, the core-shell particles are preferably cooled to 60 ° C. or lower, more preferably 55 ° C. or lower, further preferably 50 ° C. or lower, further preferably to room temperature, by the cooling and stirring step. It is particularly preferred that it be cooled.

  In the cooling and stirring step, as in the granulation step, part or all of the pressure may be reduced. The pressure at the time of depressurization is, for example, 20 kPa or less, preferably 0.01 to 20 kPa, more preferably 0.05 to 15 kPa. By reducing the pressure also during cooling, it is considered that moisture reduction and moisture reattachment can be suppressed, and as a result, particle aggregation and the like can be further reduced.

(Crushing process)
If the particles granulated in the present embodiment are aggregated (two or more core-shell particles are adhered), a pulverization step for pulverizing the aggregate may be performed.
Although the specific method of grinding is not particularly limited, for example, an impact type such as a hammer mill can be used. The raw material supply rate can be 1 to 1000 kg / h.
In pulverization, a ball mill such as a vibration ball mill, a continuous rotary ball mill, or a batch ball mill; a pot mill such as a wet pot mill or a planetary pot mill; a roller mill or the like may be used.

  The thickness of the shell of the core-shell particles finally obtained through the above steps is, for example, 0.1 to 10 μm, preferably 0.5 to 5 μm, and more preferably 1 to 3 μm. In addition, the thickness of the shell and the uniformity of the thickness of the shell appear, for example, by cutting a resin-embedded core-shell particle with a cutting machine and polishing the cut surface. It can be evaluated by observing the cross section of the core-shell particle (that can observe the cut surface of the particle). For the observation, a magnifying glass, an optical microscope, an electron microscope (for example, a scanning electron microscope) or the like can be used.

Moreover, the average particle diameter of the core in the finally obtained core-shell particles is, for example, 2 to 55 μm, preferably 4 to 50 μm, and more preferably 10 to 45 μm.
Moreover, the average particle diameter of the core-shell particles finally obtained is, for example, 3 to 60 μm, preferably 5 to 50 μm, and more preferably 10 to 45 μm.

<Core-shell particle and epoxy resin composition for sealing>
The core-shell particle of this embodiment is used as a component of the sealing epoxy resin composition. And the shell containing an epoxy resin and a hardening | curing agent is provided in the outer side of the core containing an inorganic filler (B) and at least 1 type of material (C) chosen from the group which consists of a coloring agent and an ion-trapping agent.
The average particle diameter of the core-shell particles, the average particle diameter of the core, the thickness of the shell, and the like are as described above.
The core-shell particles of the present embodiment can be typically produced by the method described in <Particle production method> above.

Here, the phrase “used as a constituent of the epoxy resin composition for sealing” of the core-shell particles of the present embodiment includes both of the following.
(I) Using the core-shell particles of this embodiment alone as an epoxy resin composition for sealing (ii) Mixing and / or kneading and using the core-shell particles of the embodiment and other components

As the “other components” in the case of (ii), for example, the molten mixture (A) described in the above-described melt mixing step, the inorganic filler (B) described in the above-described charging step, a colorant, and / or Or an ion-trapping agent can be mentioned.
Coupling agents (silane coupling agents, etc.), curing catalysts (imidazoles, organic phosphines, amines, etc.), mold release agents (natural wax, synthetic wax, higher fatty acids or metal salts thereof, paraffin, polyethylene oxide, etc. ), Low stress agents (silicone oil, silicone rubber, etc.), flame retardants (aluminum hydroxide, etc.), antioxidants and the like.

  In any case of the above (i) and (ii), the core-shell particles of the present embodiment (or a mixture / kneaded product of the core-shell particles and other components) are practically used as an epoxy resin composition for sealing. When done, it may be tableted into an appropriate form.

  The sealing epoxy resin composition (including the above-described core-shell particles) of the present embodiment can be preferably applied for sealing electronic devices and the like. For example, an electronic device such as a semiconductor element can be sealed by curing using the sealing epoxy resin composition of the present embodiment as a mold resin. Examples of the curing molding method include known methods such as a transfer molding method, a compression molding method, and an injection molding method.

The electronic device to be sealed is not particularly limited. For example, SIP (Single Inline Package), HSIP (SIP with Heathink), ZIP (Zig-zag Inline Package), DIP (Dual Inline Package), SDIP (Shrink Dusk) Inline Package), SOP (Small Small Package), SSOP (Shrink Small Outline Package), TSOP (Thin Small Outline Package), SOJ (Small Outline J-leaded Package), QF P
Examples of such packages include Fine Pitch), TQFP (Thin Quad Flat Package), QFJ (PLCC) (Quad Flat J-leaded Package), and BGA (Ball Grid Array).

  As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and can employ | adopt various structures other than the above. Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Embodiments of the present invention will be described in detail based on examples and comparative examples. In addition, this invention is not limited to an Example.

<Example 1>
1. ~ 5. The core-shell particles were obtained by this process.
1. Melt mixing process First, the following raw materials were prepared.
Epoxy resin: Phenol aralkyl type epoxy resin containing phenylene skeleton (Nippon Kayaku Co., Ltd., NC-3000, softening point 58 ° C., epoxy equivalent 277) 80 parts by mass Curing agent: Phenol aralkyl resin containing biphenylene skeleton (Maywa Kasei Co. , MEH7851S) 19 parts by mass, carnauba wax 0.5 parts by mass, silane coupling agent: γ-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-803) 0.5 parts by mass

Next, the above epoxy resin, curing agent and carnauba wax were charged into a heating kettle and heated with a heat medium oil at 150 ° C. When the material temperature exceeded 100 ° C., stirring with a stirring blade was started, and when the material temperature exceeded 120 ° C., the above coupling agent was added, and then stirred for 5 minutes.
After completion of the stirring, the mixture was transferred to another container and cooled at 10 ° C. It cooled until material temperature became 20 degrees C or less, and pulverized with the hammer mill after that.
Thus, a pulverized molten mixture having an average particle diameter of 700 μm was obtained.

2. Input process The following components were charged into the tank body of the agitator.
・ The above 1. 1.0 parts by mass of the pulverized product of the molten mixture obtained in the above: Inorganic filler: fused spherical silica 1 (manufactured by Denki Kagaku Kogyo Co., Ltd., FB-950, median diameter D50: 23 μm) 75 parts by mass: Inorganic filler: fused spherical Silica 2 (manufactured by Admatechs, SO-25R, median diameter D50: 0.5 μm) 10 parts by mass / coloring agent: carbon black (manufactured by Mitsubishi Chemical, # 5) 0.3 part by mass / ion scavenger: hydrotal Site (Kyowa Chemical Co., Ltd., DHT-4H) 0.3 parts by mass

  In addition, as a stirring apparatus, the clearance (distance between the front-end | tip of a stirring blade and a tank main body) is 3.0 mm. This stirring device was equipped with a motor and speed regulator for stirring, a lid for stirring in a sealed state, a pump for decompression, a heater for temperature adjustment, a viewing window, and the like.

3. Granulation step 2. The components charged in the tank body were heated by a heater provided in the stirring device while mixing by rotating the stirring blade so that the linear velocity at the tip was 1.0 m / s. The temperature of the contents in the tank body was maintained at 120 ° C., and the stirring blade continued to rotate under normal pressure for 30 minutes. In addition, the temperature of the content in a tank main body was confirmed with the radiation thermometer from the observation window with which a stirring apparatus is provided.
Thereby, the core-shell particle | grains provided with the shell containing a molten mixture on the outer side of the core containing an inorganic filler, a coloring agent, and an ion-trapping agent were granulated.

4). Cooling and stirring step 3. After the step, the heating of the heater was weakened, and the stirring blade was rotated so that the linear velocity at the tip was 1.0 m / s, and cooled for 120 minutes until the temperature of the core-shell particles became 45 ° C. or lower.

5. Grinding step When partial aggregation of the core-shell particles is confirmed, the above 4. The core-shell particles cooled in (1) were put into a hammer mill and processed.

<Examples 2 to 4 and Comparative Examples>
Core-shell particles were produced in the same manner as in Example 1 except that the conditions during the granulation step and the cooling and stirring step were changed as shown in the table below.
In particular, in Example 4, the pressure in the tank body was reduced to 10 kPa during the granulation step.

<Evaluation>
[Average particle size of core-shell particles] and [Uniformity of particle size distribution]
Data of particle size distribution was acquired using a wet particle size distribution analyzer LA-950 manufactured by Horiba.
The average particle size was calculated by arithmetically averaging this data.
Further, a cumulative 10% value (D10) and a cumulative 90% value (D90) are obtained from the data, and the value of D90 / D10 is calculated and used as an index of the “width” of the particle size distribution (of D90 / D10 The smaller the value, the narrower the particle size distribution, indicating that the core-shell particles are uniformly granulated). This time, as an evaluation standard, a case where the value of D90 / D10 is less than 15 is (good), and a case where it is 15 or more is x (bad).

[Shell thickness uniformity]
The cut surface of the core-shell particles was observed with a scanning electron microscope. The cross-section of the core-shell particles was obtained by cutting the core-shell particles embedded in the resin with a cutting machine as described above.
If the outer periphery of the core was coated almost uniformly on the whole surface, it was rated as “good”, if not partially coated, “△” (normal), and if almost or not coated, “x” (bad).

[Uniformity of material mixing]
The obtained core-shell particles were visually observed.
As a result of the uniform dispersion of carbon black, each core shell had a uniform color (circle) (good). When the dispersibility of carbon black was poor and black spots were observed, it was marked with x (bad).

[Regarding particle aggregation]
100 parts by mass of the obtained core-shell particles were sieved with a sieve having an opening of 1 mm, and the proportion of aggregated particles remaining on the sieve was measured. If the residual amount was less than 1 part by mass, it was rated as ◯ (good), and if it was 1 part by mass or more, x (bad).

As shown in Table 2, the core-shell particles of Examples 1 to 4 obtained through each step of the melt mixing step, the charging step, and the granulation step (the linear velocity at the tip of the stirring blade is 0.1 m / s or more) The shell thickness uniformity, the material mixing uniformity, the particle aggregation, the particle size distribution uniformity and the like were good. That is, the homogeneity of the particles used as the constituent component of the sealing epoxy resin composition could be improved by the method for producing particles of the present embodiment.
In particular, it was found that the uniformity of the thickness of the shell is further improved when the linear velocity at the tip of the stirring blade in the granulation step is 1.0 m / s or more.

  On the other hand, the core-shell particles of the comparative example obtained under the condition that the linear velocity at the tip of the stirring blade in the granulation step is 0.05 m / s, the shell thickness uniformity, the material mixing uniformity, the particle aggregation and the particle size It was a result inferior to Examples 1-4 in all of the uniformity of distribution. It is presumed that a large shearing force due to stirring at a certain speed or more is related to the improvement of the homogeneity of the particles.

<Preparation of epoxy resin composition for sealing, etc.>
(I) 86.6 parts by mass of the core-shell particles obtained in Example 1, and (ii) the above 1. Prepare 12.2 parts by mass of the pulverized product of the molten mixture obtained in the melt mixing step and (iii) separately prepared particles containing 1.0 part by mass of the epoxy resin curing agent and 0.2 part by mass of the epoxy curing catalyst. did. These were mixed and pulverized with a hammer mill to obtain an epoxy resin composition for sealing. When this composition was applied to the sealing of a semiconductor device, sealing could be performed.

1 Stirring device 2 Stirring blade 3 Shaft 4 Tank body

Claims (11)

A method for producing particles used as a constituent of an epoxy resin composition for sealing,
A melt mixing step for obtaining a melt mixture (A) of an epoxy resin and a curing agent;
A charging step of charging the molten mixture (A), the inorganic filler (B), and at least one material (C) selected from the group consisting of a colorant and an ion scavenger into a stirrer equipped with a stirring blade. When,
After the charging step, the components charged in the stirrer are heated to 110 ° C. or higher by mixing and driving the stirring blade at a linear velocity of 0.1 m / s or more at the tip, and the inorganic A granulation step of obtaining core-shell particles having a shell containing the molten mixture (A) outside a core containing the filler (B) and the material (C). A method for producing the particles according to claim 1,
In the granulation step, the method for producing particles, wherein the time for which the component charged in the stirring device is 110 ° C. or more is 5 to 200 minutes. It is a manufacturing method of Claim 1 or 2, Comprising:
The manufacturing method of particle | grains including the cooling stirring process which rotates the said stirring blade after the said granulation process and cools, stirring the component in the said stirring apparatus. It is a manufacturing method given in any 1 paragraph of Claims 1-3,
A method for producing particles, wherein part or all of the granulation step is performed under a reduced pressure of 30 kPa or less. The manufacturing method according to any one of claims 1 to 4,
The manufacturing method of particle | grains including the moisture reduction process which reduces the moisture which the said inorganic filler (B) contains. It is a manufacturing method given in any 1 paragraph of Claims 1-5,
A method for producing particles, comprising a pulverization step of pulverizing the aggregate of the core-shell particles. The manufacturing method according to any one of claims 1 to 6,
The manufacturing method of particle | grains whose ratio of the said molten mixture (A) in all the components thrown into the said stirring apparatus at the said addition process is 15 mass% or less. It is a manufacturing method of any one of Claims 1-7,
The manufacturing method of particle | grains whose shell thickness of the said core-shell particle | grain is 0.1-5 micrometers.   For sealing, provided with a shell containing an epoxy resin and a curing agent on the outside of a core containing an inorganic filler (B) and at least one material (C) selected from the group consisting of a colorant and an ion scavenger Core-shell particles used as a component of the epoxy resin composition. The core-shell particle according to claim 9, wherein
Core-shell particles having a thickness of the shell of 0.1 to 5 μm.   The epoxy resin composition for sealing containing the core-shell particle of Claim 9 or 10.

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