JPH0557742A - Method for molding thermosetting resin product - Google Patents

Abstract

PURPOSE:To eliminate defects, such as voids, in the molding of a thermosetting resin product by applying the pressure necessary for molding to the whole of a cavity without extending a molding cycle. CONSTITUTION:As the solid resin material 8 charged in a pot 1, a plurality of solid materials having different reaction speeds are used in combination or a solid resin material molded so as to have different reaction speeds according to places is used. By this method, since the curing of the resin quickly flowing in a cavity 4 can be delayed, the resin in the whole region of the cavity 4 can be held to a molten state when the cavity is perfectly filled with the resin. As a result, since the pressure necessary for molding is applied to the whole of the cavity, defects such as voids can be prevented and the resin flowing in the cavity 4 later can be rapidly cured contrarily and the resins in the cavity can be solidified almost simultaneously and, therefore, a molding cycle can be shortened.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for molding a thermosetting resin product.

[0002]

2. Description of the Related Art In recent years, a thermosetting resin molding method has been used for resin sealing of electronic parts and has become an indispensable technique for manufacturing semiconductor packages.

A conventional method for molding a thermosetting resin product will be described below with reference to the drawings.

FIG. 4 is a cross-sectional view of a resin molding die used for molding a conventional thermosetting resin product. In the figure, 1 is a pot, 2 is a runner, 3 is a gate, 4 is a cavity, 6 is an upper mold, 7 is a lower mold, and 10 is a protruding pin. First, the solid resin material 8 is put into the pot 1. Next is the plunger 5
And pressure is applied to the resin material 8 that has been melted by being heated by the heat transfer from the pot 1. The resin is filled in the cavity 4 through the runner 2 and the gate 3. The resin filled in the cavity undergoes a hardening reaction due to heat transfer from the wall surface of the cavity, and after a predetermined time required for solidifying the entire resin in the cavity, a molded product is taken out.
Here, as the resin material put in the pot, one substantially homogeneous solid material in which the curing agent and the curing accelerator are mixed and pressed so as to be distributed almost uniformly is used. Therefore, under the same temperature condition, the rate of curing reaction is
It is constant regardless of the place. Figure 5 shows the molding process.
The faster the resin starts to flow, the longer it receives heat from the mold wall surface, and the faster the curing reaction proceeds. FIG. 5 shows the resin 11 which has entered the cavity 4 and which has been cured first.

[0005]

If the degree of curing differs depending on the location of the cavity 4 as described above, the quality of the molded product becomes non-uniform. In particular, since the hardened resin 11 is no longer a fluid, a pressure necessary to form a molded product cannot be applied to this portion, and a void is generated. As a method of solving this, a method of using a resin material having a slow reaction rate so as to prevent the resin that has previously flown into the cavity from hardening is conceivable, but this has a problem of prolonging the molding cycle.

In view of the above-mentioned problems, the present invention is necessary for molding when the cavity is completely filled with resin by delaying the curing reaction of the resin that first flows into the cavity without extending the molding cycle. An object of the present invention is to provide a method for molding a thermosetting resin product in which pressure is applied to the entire cavity and defects in the molded product such as voids are eliminated.

[0007]

In order to achieve the above object, the molding method of the present invention comprises a pot for heating and melting a solid resin material and a plunger for pressurizing the resin material in the pot. In a method of molding a thermosetting resin product using a runner connected to a pot and a resin molding die that supplies a molten resin material to a cavity through a gate at the end of the runner, the thermosetting resin product is put into the pot. As the solid resin material, a plurality of solid materials having different reaction rates are used in combination, or a solid resin material having a different reaction rate depending on a place is used.

[0008]

By the above-described method, the hardening of the resin that flows into the cavity quickly can be delayed, so that when the cavity is completely filled with the resin, the resin in the entire area of the cavity can be kept in a molten state. As a result, the pressure required for molding is applied to the entire cavity, so that defective molded products such as voids can be prevented. On the contrary, the resin that flows into the cavity later can be cured earlier, and the resin in the cavity can be solidified almost at the same time, so that the molding cycle can be shortened.

[0009]

EXAMPLE A method for molding a thermosetting resin product according to the first example of the present invention will be described below. 1 and 2 are cross-sectional views of a resin molding die showing a molding method according to this embodiment, and the same components as those of the conventional example shown in FIG. That is, 1 is a pot, 2 is a runner, 3 is a gate,
4 is a cavity, 6 is an upper mold, 7 is a lower mold, 8 is a solid resin material, and 9 is a molten resin. As the solid resin material 8, three solid materials having different reaction rates are stacked and used. As the lower solid material 8a that is heated and melted in the pot and starts to flow, a material having a slow reaction rate is used, and a solid material having a faster reaction rate is used toward the upper side. Such three solid resin materials having different reaction rates are molded by changing the compounding ratio of the curing agent and the curing accelerator. In the figure, the volume of the solid material 8c is larger than the other solid materials 8a and 8b, but this is because the solid material 8c contains the resin that remains in the pot or runner and does not flow into the cavity during the resin filling process.

As described above, as the lower solid material 8a which is heated and melted quickly in the pot and starts to flow, one having a slow reaction rate is used, and solid materials having a fast reaction rate are gradually stacked and used. Since the hardening of the resin that flows into the cavity early can be delayed, when the cavity is completely filled with the resin as shown in FIG. 2, the resin in the entire area of the cavity can be kept in a molten state. As a result, the pressure required for molding is applied to the entire cavity, so that defective molded products such as voids can be prevented. On the contrary, the resin that flows into the cavity later can be cured earlier, and the resin in the cavity can be solidified almost at the same time, so that the molding cycle can be shortened.

The method of combining solid materials having different reaction rates depends on molding conditions such as mold temperature and plunger descent rate, product dimensions, and runner dimensions, but is determined by a molding experiment or a resin material test and a curing reaction simulation. be able to.

The second embodiment of the present invention will be described below. FIG. 3 is a cross-sectional view of the resin molding die in the embodiment,
The same components as those of the conventional example shown in FIG. That is, 1 is a pot, 2 is a runner, 3 is a gate, 4 is a cavity, 6 is an upper mold, 7 is a lower mold, 8 is a solid resin material, and 9 is a molten resin. Solid resin material 8
Uses a solid material that is molded so that the reaction rate varies depending on the location. This solid resin material is pressed and solidified by changing the compounding ratio of the curing agent and the curing accelerator so that the reaction rate becomes slower at the lower side where it is heated and melted and starts to flow in the pot, and the reaction rate becomes faster at the upper side. It is integrally molded. Also in this case, the hardening of the resin that flows into the cavity early can be delayed as in the first embodiment, so that when the cavity is completely filled with the resin, the resin in the entire area of the cavity can be kept in a molten state. As a result, the pressure required for molding is applied to the entire cavity, so that defective molded products such as voids can be prevented. On the contrary, the resin that flows into the cavity later can be cured earlier, and the resin in the cavity can be solidified almost at the same time, so that the molding cycle can be shortened.

In this embodiment, the case where the plunger descends from the upper side is shown. However, in the case of the mold in which the plunger rises from the lower side, the order of the resin flowing into the cavity is upside down. A resin material having a slower reaction rate is placed on the upper side in the pot, and a resin having a faster reaction rate is placed on the lower side.

The method of combining solid materials having different reaction rates varies depending on molding conditions such as mold temperature and plunger descent rate and product dimensions and runner dimensions, but can be determined by molding experiments or resin flow and curing reaction simulations. it can.

[0015]

As described above, according to the present invention, it is possible to delay the hardening of the resin that quickly flows into the cavity. Therefore, when the cavity is completely filled with the resin, the resin throughout the cavity is kept in a molten state. be able to. As a result, the pressure required for molding is applied to the entire cavity,
Molded product defects such as voids can be prevented. In addition, since the resin in the cavity can be solidified almost at the same time by accelerating the curing of the resin that flows into the cavity later, the molding cycle can be shortened.

[Brief description of drawings]

FIG. 1 is a sectional view of a resin molding die showing a method for molding a thermosetting resin product according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a melting, flowing and solidifying state of a resin in a molding process of the same example.

FIG. 3 is a sectional view of a resin molding die showing a method for molding a thermosetting resin product according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a resin molding die showing a conventional method for molding a thermosetting resin product.

5 is an explanatory diagram showing the melting, flowing, and solidifying state of the resin in the molding process shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 pot 2 runner 3 gate 4 cavity 5 plunger 6 upper mold 7 lower mold 8 solid resin material 9 molten resin 10 extrusion pin 11 cured resin

Claims (2)

[Claims] 1. A runner connected to the pot, comprising a pot for heating and melting a solid resin material and a plunger for pressurizing the resin material in the pot, and a cavity at the end of the runner through a gate. A method of molding a thermosetting resin product using a resin molding die that supplies a molten resin material, wherein a plurality of solid materials having different reaction rates are combined as the solid resin material to be put into the pot. A method for molding a thermosetting resin product, which is characterized by being used. 2. A cavity that has a pot for heating and melting a solid resin material and a plunger for pressurizing the resin material in the pot, and a runner connected to the pot, and a cavity at the end of the runner through a gate. A method of molding a thermosetting resin product using a resin molding die that supplies a molten resin material, wherein the solid resin material to be put into the pot has a reaction rate that varies depending on the location. A method for molding a thermosetting resin product, which comprises using a material.