JP3243266B2 - Silica regeneration and recovery method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating and recovering silica. More specifically, the present invention
A new silica recovery method that can efficiently recover and recover silica as a valuable material from silica-containing resin molding materials such as semiconductor encapsulation molding materials without causing environmental pollution, and can reuse them as these molding materials It is about.

[0002]

2. Description of the Related Art Conventionally, resin moldings used in various fields such as electric / electronic equipment, machinery, building materials, daily necessities, etc. include fillers, heat-resistant additives and other functions for imparting other functions. In many cases, silica is blended. For example, such an epoxy resin molding material containing silica has been used in resin sealing of semiconductors. As in the case of general resin molding materials, even with such silica-containing molding materials, from the manufacturing process, molding material waste is generated at the time of changing the product type or as defective products, and From the process, waste as molding burrs such as sprues, culls and runners is generated.

[0003] Usually, these molding wastes are buried in a predetermined place after pulverization and baking, or the wastes are directly buried, or those whose history in the process is clear are reused. Has been working to reduce environmental pollution due to waste and to recycle valuable resources.

[0004]

However, in the case of the conventional silica-containing resin molding material, the reuse of silica compounded as a valuable material is limited by the silica that can be recycled and mixed. The conditions were severe, the range of use was extremely limited, and it was almost impossible to reuse them. This has been attributed to the fact that it is difficult to ensure the reliability of the molded article due to recycling, and a method of reclaiming and recovering sufficient to satisfy the reliability has not been established.

[0005] For this reason, conventionally, it has not been possible to drastically eliminate environmental pollution nor to recover and reuse valuable silica. The present invention has been made in view of the above circumstances, and eliminates the drawbacks of the conventional waste treatment of a silica-containing resin molding material, drastically reduces environmental pollution, and increases the value of valuable silica. The purpose is to provide a new method that enables efficient recovery and recovery.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a silica-containing resin molding material and / or crushing molding waste material from the molding step to transfer silica crystals. Provided is a method for regenerating and recovering silica, which comprises classifying after firing at a temperature not higher than the temperature.

[0007] That is, the present invention relates to a semiconductor encapsulant, various molded articles of electric and electronic devices, machinery, and other molded article waste products generated from a process of manufacturing a resin molded material containing silica used in various fields. Alternatively, a silica-containing material as a precious valuable material can be recovered at high efficiency and low cost from waste products such as molding burrs generated from the molding process of these molding materials, and can be reused.

As a method for this purpose, as shown in FIG. 1, for example, in the present invention, in the manufacturing process of a molded material, first, a waste product (A) generated as a type change, a defective product, a sprue, a cull, The molded burr waste (B) generated as a runner or the like is collected and crushed (C) to reduce the bulk. Then cracked and waste products, silica transition temperature or less, for example molded material calcined at a temperature of about 8 from 00 to 900 ° C. in the case of the epoxy resin molding material or the like for semiconductor encapsulation (D). At this time, it is advantageous to supply air or the like and carry out catalytic combustion so that carbon from the resin component does not remain.

After that, classification (E) is performed, the particle size is adjusted, and silica (F) to be reused as a compounding material for the molding material is recovered. In addition, from the viewpoint of maintaining the quality of silica at the time of reuse, it is desirable to appropriately employ a means for preventing contamination of impurities. For example, removal of metal by magnetic force separation, particularly, Before classification,
Or it is desirable to do it later.

[0010]

In the present invention, since it is essential that the waste product of the silica-containing molding material is subjected to calcination (D) treatment under a high temperature condition not higher than the transition temperature of silica, the silica-containing material is immediately reused in its original form. It can be collected when it can. For example, as a semiconductor encapsulant, usually, an organic substance is about 35 to 15%, and an inorganic substance such as silica is 65 to 8%.
Although about 5% is blended, all of the effective amount of the silica can be recovered by the method of the present invention.

[0011] Quality maintenance for reuse is ensured by this method.

[0012]

The present invention will be described in more detail with reference to the following examples. FIG. 2 is a block diagram showing an example of an apparatus configuration for the method of the present invention. For example, as illustrated in FIG. 2, in the present invention, in order to regenerate and recover silica from a silica-containing resin molding material waste, a crushing (C) device, a firing (D) device,
Classification (E) device, iron removal (G) device and gas treatment (H)
The system is composed of devices. Wastes, that is, wastes (A) of the molding material from the manufacturing process and wastes (B) from the molding process are put into the coarse crushing (C) device, and the silica (F) is removed from the iron removal (G) device. Is to be recycled and collected.

In such a configuration, details thereof are as follows, for example. <Crushing (C) device> The crushing machine (1) is used for the purpose of reducing the bulk to improve the combustibility of the waste products (A) and (B). Various types of the crusher (1) can be used, and the size and the processing capacity are determined by the combustion efficiency in the next firing (D) device. Waste products (A) (B)
The same applies to the size after crushing.

The molded material waste crushed by the crusher (1) is guided to a material charging chute (3) via, for example, a screw feeder (2). <Firing (D) device> From the material charging chute (3), the coarsely crushed waste is charged into, for example, a rotary kiln (4). Baking is performed in this rotary kiln (4).

The material input chute (3) is provided with an air inlet (5) for injecting combustion air and a cooling jacket (6). And the cleaning effect of the material input chute (3) is enhanced. This measure makes the treatment of the uncured molding material particularly effective.

The rotary kiln (4) is provided with an electric heater (7) or a burner (8) as a heating source. You may use these both together. Even when using a burner (8) by direct fire of a fuel (for example, fossil fuel or the like), this burner is used as an external heating source of the firing chamber (40) of the rotary kiln (4), and burner combustion gas and molded material waste are used. Avoid direct contact with the product. Heating by the electric heater (7) and / or the burner (8) may be set to about 1000 to 1100 ° C., the sintering temperature of the combustion chamber (40) within the 8 00-900 approximately ° C.. Firing at this temperature can be performed, for example, for one hour or more.

It is preferable to use, for example, a SUS heat-resistant material in the firing chamber (40) to prevent metal oxide from being mixed. <Gas treatment (H) device> Exhaust gas from the rotary kiln (4) is led to a heat exchanger (9) for exhaust heat recovery and exhausted. The outside air introduced through the filter (10) is preheated in the heat exchanger (9), and the preheated air is supplied from the combustion air inlet (5) to the burner (8). Supply as air for.

As described above, by utilizing heat from exhaust gas, self-combustion heat can be used as energy. <Classification (E) device> The treated fired product burned in the rotary kiln (4) is guided from the fired product outlet (11) to the classifier (12). In the classifier (12), the particles are adjusted and classified to a required particle size for reuse.

Various kinds of classifiers can be used. <Iron removal (G) device> After the classification, the iron removal treatment is performed, for example, by a magnetic separator (13). Similarly, other kinds of metals can be appropriately selected. In the recycling and recovery system having the above-mentioned configuration, for example, from a waste product having silica in a molding material having physical properties as shown in Table 1, firing in a rotary kiln (4) is performed at 800 ° C. and 1 hour. Similarly, silica having the physical properties shown in Table 1 was recovered and recovered.

The silica almost in its original state was recovered and could be immediately reused.

[0021]

[Table 1]

[0022]

According to the present invention, as described above in detail, it is possible to efficiently recover and recover valuable silica from silica-containing resin molding waste without causing environmental pollution.

[Brief description of the drawings]

FIG. 1 is a process block diagram showing a method of the present invention.

FIG. 2 is a configuration block diagram showing an example of an apparatus for carrying out the method of the present invention.

[Explanation of symbols]

 A Manufacturing process waste B Molding process waste C Crushing D Firing E Classification F Silica G Iron removal H Gas treatment 1 Crusher 2 Screw feeder 3 Material input chute 4 Rotary kiln 40 Firing chamber 5 Air inlet 6 Cooling jacket 7 Electricity Heater 8 Burner 9 Heat exchanger 10 Filter 11 Burned product outlet 12 Classified product 13 Magnetic sorter

Claims (4)

(57) [Claims] Claims: 1. A method for reclaiming and recovering silica, comprising crushing a molded product waste product from a production process and / or a molding process of a silica-containing resin molding material, calcination at a temperature lower than a transition temperature of silica crystal, and classification. . 2. A 8 00-900 reproducing method for recovering silica of claim 1 is fired at ° C.. 3. The method of claim 1, wherein iron is removed before or after the classification. 4. The method of claim 1, wherein the particle size is adjusted at the time of classification.