JP2000313012A - Apparatus for granulating thermosetting resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable method for granulating a resin compsn. SOLUTION: In an apparatus for granulating a thermosetting resin compsn. wherein a molten and kneaded thermosetting resin compsn. can be fed from an opening through a double pipe type cylindrical body 5 which can be cooled by passing a cooling medium between the inner wall and the outer wall and a punched metal net formed of a non- magnetic material with a high thermal conductivity which has small holes with different diameters at an arbitrary ratio on the outer periphery is brought into contact with a magnetic material on its top part and/or bottom part and the magnetic material is heated by energizing an AC electric source to an exciting coil provided in the neighborhood of the magnetic material and by passing the thermosetting resin compsn. through the small holes of the punched metal net uniformly heated by heat conduction by centrifugal force, the thermosetting resin compsn. can be granulated into multi- dispersed particles which can be filled with high density at a regulated ratio, as the outer tank 8 for recovering the granulated thermosetting resin compsn. has a wall face for granulation collision part with an inclination of 10-80 degree and a cooling jacket on its outer periphery, the resin characteristics can be prevented from being deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for granulating a thermosetting resin composition, and more particularly to a method for controlling the particle size to a particle size which can be filled at a high density without containing fine powder which causes deterioration of working environment and equipment contamination. The present invention relates to an apparatus for granulating a thermosetting resin composition, which has high measurement accuracy because of being capable of reducing the amount of air contained during tablet molding.

[0002]

2. Description of the Related Art A thermosetting resin composition (hereinafter referred to as a resin composition) is generally composed of a resin and additives such as a curing agent, a curing accelerator, a flame retardant, a pigment release agent, and an inorganic filler.
After the components are premixed in a mixer, they are formed into tablets of a desired shape through sheeting, cooling, and pulverizing steps using a roll or an extruder. However, in a granulation method that requires a pulverizing step, it is possible to adjust the particle size distribution, but it is not possible to selectively pulverize particles that can be packed at high density. In addition, fine powder is generated at the time of pulverization. For example, even if a classification step is added, the fine powder that has aggregated and adhered cannot be completely removed. Therefore, when a tablet is formed using crushed powder, a large amount of air is contained in the tablet, and during molding, degassing becomes insufficient and the reliability of the sealed semiconductor containing bubbles in the molded product is reduced. In addition, the fine powder generated during the pulverization and tableting process causes deterioration of the working environment, and during the molding process, fine powder is generated from the tablet, which reduces the reliability of the molded product and deteriorates the working environment due to contamination of equipment. I was letting it.

A method for granulating a thermosetting resin is disclosed in JP-A-50-7
8644, JP-A-51-40678, JP-A-52-59663, JP-A-52-59665, JP-A-59-190818, and JP-A-5-190818.
Although these methods are disclosed in Japanese Patent Application Laid-Open No. 0-180839, these methods are methods in which a die or the like is attached to the tip of an extruder to perform hot cutting.
JP-A-31719, JP-A-11-029075, and JP-A-11-029076 are disclosed, all of which can selectively granulate particles having an arbitrary particle size capable of high-density packing. is not.

[0004]

The present invention concluded that in order to solve the above-mentioned problems, it is necessary to directly granulate without pulverization after the preheating kneading step. As a result of intensive studies on the granulation method, the present inventors have reached the present invention. Since the present invention passes through small holes of a punched wire mesh designed to obtain particles having a particle size capable of filling a resin composition in a molten state at a high density, generation of fine powder which causes deterioration of work environment and equipment contamination is reduced. Not only without
It is an object of the present invention to provide a method of granulating a resin composition, which can reduce a decrease in reliability due to the generation of voids by improving measurement accuracy and reducing air contained during tablet molding.

[0005]

That is, the present invention provides a method of melting and kneading heat through a double-pipe cylindrical body provided at the top of a rotating rotor and capable of cooling by passing a refrigerant between an inner wall and an outer wall. A curable resin composition can be supplied from an opening, and a punched wire mesh formed of a non-magnetic material having a high thermal conductivity and having small holes of different diameters on the outer periphery thereof at an arbitrary ratio has an upper and / or lower magnetic material. The magnetic material is heated by applying an AC power supply to an exciting coil provided in the vicinity of the magnetic material, and is passed through the small holes of the punched wire mesh, which is uniformly heated by heat conduction, by centrifugal force. A granulator for a thermosetting resin composition capable of granulating polydispersed particles that can be packed at a high density by collecting in an outer tank at a ratio according to a rule, and an outer tank for collecting a further milled resin. Is the milling opponent The wall of the part is inclined at 10 to 80 degrees, and a cooling jacket is provided on the outer periphery thereof, which causes deterioration of resin characteristics. It is a granulator.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The melt-kneaded resin composition of the present invention refers to a resin and a curing agent, a curing accelerator, a flame retardant,
It is composed of an additive such as a pigment release agent and an inorganic filler, and is preliminarily mixed with a mixer and then melted by a heating kneader such as a twin screw extruder to form a uniform dispersion.
The type of the resin is not particularly limited as long as it is thermosetting, and may be an epoxy resin, a phenol resin, an epoxy-polyester resin, a polyester resin, an acrylic resin, an acryl-polyester resin, a polyimide resin, or a modified system thereof, or a mixture thereof. Any of the systems can be used. The curing agent is selected according to the resin, and the curing accelerator generally includes imidazole, organic phosphine, 1,8-diazabicyclo (5,
(4,0) Undecene-7 or the like is used. Further, if necessary, a silane coupling agent, a flame retardant such as antimony trioxide, a release agent such as carbon black, carnauba or low molecular weight polyethylene, a silicone oil or a rubber for maintaining the flexibility of the resin composition. You may add suitably. Silica powder for decreasing thermal expansion coefficient and improving impact resistance,
Fillers such as calcium carbonate powder, talc powder, magnesia powder, and wood powder can be blended.

In general, the porosity is smaller in a polydisperse system having different sizes than in the case where the size of the particles is uniform,
It is known that it can be packed more densely. For example
Taking the packing model of Horshield as an example, the porosity of hexagonal close-packed equal-sized spherical particles is 0.2595, whereas the porosity is surrounded by a square hole surrounded by six spheres and four spheres. When the largest spheres that can enter the triangular hole are sequentially filled, the first isometric sphere is the primary sphere, the largest sphere that can enter the square hole is the secondary sphere, and the largest sphere that can enter the triangular hole is the tertiary sphere, primary The largest sphere that can enter the gap between the sphere and the secondary sphere is the fourth sphere, the largest sphere that can enter the gap between the primary and the tertiary sphere is the fifth sphere, and the last remaining gap is the finest equal-sized sphere. The porosity at the time of filling is 0.039.
In other words, when granulation is performed to a particle size conforming to a rule as compared with a case where granulation is performed to a uniform equal-sized sphere or irregular size, higher-density filling can be performed.

According to the present invention, the upper portion and / or
Alternatively, the rotor is provided with a punched wire mesh formed of a non-magnetic material having a high thermal conductivity having an arbitrary ratio of small holes having different diameters in contact with a magnetic material at a lower portion, and an excitation coil installed near the magnetic material has an alternating current. By energizing the power supply, the upper and / or lower magnetic material of the punched wire mesh can be heated,
In a resin composition granulator capable of uniformly heating a punched wire gauze from the height of the heat conduction, a resin composition melt-kneaded through a double-pipe cylindrical body installed on an upper part of a rotating rotor is passed through an opening. The polydispersed particles that can be easily filled at high density by supplying and contacting with the punched wire mesh heated by heat conduction and passing through the small holes by centrifugal force without increasing the melt viscosity of the resin in accordance with the rules Can be granulated at the desired ratio.
The outer tank for collecting the granulated resin composition is inclined to prevent the adhesion of the granulated product, and has a cooling jacket on its outer periphery. Without inviting, without generating a fine powder that causes deterioration of work environment and equipment contamination, improvement of weighing accuracy and reduction of air included in tablet molding reduces reliability deterioration caused by void generation. A method for granulating the resin composition can be provided.

Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view for carrying out a method of granulating an epoxy resin composition for semiconductor encapsulation, and FIG. 2 is a rotor and an exciting coil;
FIG. 3 shows a double-pipe cylindrical body installed above the rotor. The resin composition melt-kneaded in the twin-screw extruder 9 is supplied to the rotor 1 through a cooled double-pipe cylindrical body 5 through a refrigerant between an inner wall and an outer wall. At this time, double-pipe cylindrical body 5
If is not cooled, the resin composition tends to adhere to the wall of the double-pipe cylindrical body, and it is difficult to supply a stable resin composition, which is not preferable. The rotor 1 is connected to a motor 10 and can be rotated at an arbitrary rotation speed. A magnetic material 3 in contact with a punched wire mesh 2 made of a non-magnetic material having a high thermal conductivity and having small holes of different diameters provided at an arbitrary ratio provided on the outer periphery of a rotor 1 is provided with an exciting coil provided in the vicinity thereof. Heating is caused by eddy current loss and hysteresis loss associated with the passage of the alternating magnetic flux generated by applying the AC power generated by the AC power generator 6 to 4. The magnetic material is, for example, an iron material or silicon steel, and one or two or more magnetic materials can be used in combination. Heated magnetic material 3
Is used as a heat source to heat the punched wire mesh by heat conduction.
The punched wire mesh 2 is formed of a nonmagnetic material having a high thermal conductivity, and can be heated very uniformly. The non-magnetic material includes, for example, copper and aluminum, and one or two or more magnetic materials can be used in combination. After the resin composition is supplied to the rotor 1, the resin composition flies and moves to the punched wire mesh 2 heated by centrifugal force.

[0010] The resin composition in contact with the heated punched metal net 2 is easily discharged through the holes of the punched metal net 2 without increasing the melt viscosity. The heating temperature can be set arbitrarily according to the characteristics of the applied resin composition. In the case of a thermosetting resin, if the heating temperature is too high, the curing of the resin composition may proceed and the properties may be degraded or the holes in the punched wire mesh 2 may be clogged. Since the contact time of the wire mesh 2 is extremely short, the influence on the characteristics is extremely small. Further, since the punched wire mesh is uniformly heated, local changes in properties are extremely small.

The resin composition granulated to a particle size suitable for high-density packing is collected in an outer tank 8 provided around the rotor 1. The outer tank 8 is provided with a slant of 10 to 80 degrees, preferably 25 to 65 degrees on the collision surface in order to prevent the granules from adhering to the inner wall and preventing the granules from fusing together. If the inclination is too small, the collision energy of the granulated product cannot be sufficiently dispersed,
Adhesion to the wall surface occurs. On the other hand, if the inclination is too large, the decrease rate of the flying speed of the granulated product is small and the flight direction is toward the outer tank wall surface, so that there is a possibility that adhesion will occur at the next wall collision. Further, if the temperature of the collision surface with the granulated product becomes high, the particles easily adhere to the surface. Therefore, a cooling jacket 7 is provided around the collision surface to cool the collision surface.
If the inner diameter of the outer tank 8 is too small, the granulated product is not sufficiently cooled, so that the granulated product may adhere to the inner wall and the granulated product may be fused, which is not preferable. In general, the rotation of the rotor 1 generates an air flow to provide a cooling effect, but cold air may be introduced as needed. Although the size of the outer tank 8 depends on the amount of resin to be treated, for example, when the diameter of the rotor is 20 cm, adhesion and fusion can be prevented if the inner diameter is 100 cm. The hole diameter and the ratio of the punched metal mesh can be arbitrarily adjusted according to the properties of the resin composition to be used and the shape of the tablet to be molded so that a particle size that can be highly filled is obtained.

[0012]

EXAMPLES The present invention will be described in more detail with reference to Examples.
The epoxy resin composition for semiconductor encapsulation having the following composition was pulverized and mixed for 5 minutes by a super mixer. This mixed raw material was fed to a co-rotating twin-screw extruder 9 having a cylinder inner diameter of 65 mm as shown in FIG.
Melt kneading was performed at a resin temperature of 10 ° C. << Blending of epoxy resin composition for semiconductor encapsulation (parts by weight)}-Cresol novolak type epoxy resin 8-Brominated epoxy resin 2-Phenol novolak resin 4-Curing agent (2-methylimidazole) 0.3-Inorganic filler (Silica) 84-carnauba wax 0.1-low molecular weight polyethylene 0.1-carbon black 0.3-coupling agent 0.2-antimony trioxide 1

<< Example 1, Comparative Example 1 >> In Example 1, 3.
A punched wire mesh having hole diameters of 5 mm, 2.6 mm and 1 mm in a ratio of 1: 1: 3 was used. The above-described punched wire mesh having a height of 60 mm and a thickness of 3 mm, which was formed into a cylindrical shape, was attached to the outer periphery of a rotor having a diameter of 20 cm, the rotor was rotated at 3000 RPM, and the punched wire mesh was heated to 120 ° C. by an exciting coil. After the steady state, the resin composition in a molten state was supplied from the upper part of the rotor and granulated. In Comparative Example 1, the melt-kneaded resin composition was cooled with a cooling belt and then coarsely pulverized by a hammer mill to obtain a coarsely pulverized product having an average particle size of 800 μm and a particle size distribution of 40 μm to 10 mm. This was pulverized with a pulperizer at 4000 revolutions. As a result, 11 wt% of fine powder of 10 μm or less and 8 wt.
% Of powder having an average particle size of 70 μm. A transfer molding machine (molding conditions: mold temperature: 175 ° C., pressure: 70 kg / cm ² , molding time: 2)
Min.) And sealed with resin.
Post-curing was performed under the conditions of time. Table 1 shows the evaluation results of the sealing resin in Examples and Comparative Examples.

[0014]

[Table 1]

[0015]

EFFECTS OF THE INVENTION In the method for granulating a resin composition according to the present invention, there is no generation of fine powder which causes deterioration of the working environment and contamination of equipment, and the particle size of the granulated material can be controlled. , High density filling is possible, and bubbles contained in a molded product can be reduced, so that a highly reliable resin composition can be provided.

[Brief description of the drawings]

FIG. 1 shows a diagram for performing granulation of a resin composition of the present invention.
One example from the melt-kneading of the resin composition to the collection of granules will be described.

FIG. 2 shows an example of a sectional view of a rotor and an exciting coil 4 used in the present invention.

FIG. 3 shows an example of a cross-sectional view of a cylindrical body 5 for introducing a melt-kneaded resin composition into a rotor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Punched wire mesh 3 Magnetic material 4 Excitation coil 5 Cylindrical body 6 AC power generator 7 Cooling jacket 8 Outer tank 9 Twin screw extruder 10 Motor

Claims (2)

[Claims] 1. A thermosetting resin composition melt-kneaded through a double-pipe cylindrical body provided on an upper part of a rotating rotor and capable of being cooled by passing a refrigerant between an inner wall and an outer wall from an opening. A punched wire mesh formed of a non-magnetic material having a high thermal conductivity and having small holes of different diameters on its outer periphery at an arbitrary ratio can be supplied, and the upper and / or lower portions are in contact with the magnetic material, and the vicinity of the magnetic material The magnetic material is heated by passing an AC power supply through the excitation coil provided in, and it passes through the small holes of the punched wire mesh, which is uniformly heated by heat conduction, by centrifugal force, and is collected in the outer tank to achieve high density. An apparatus for granulating a thermosetting resin composition capable of granulating polydispersible particles that can be filled at a ratio according to a rule. 2. An outer tank for recovering a milled resin has a wall surface of a milling collision portion inclined at 10 to 80 degrees and a cooling jacket provided on an outer periphery thereof, which causes deterioration of resin characteristics. The granulating device for a thermosetting resin composition according to claim 1, wherein the granulating device can prevent the adhesion of granules.