JPH0939056A - Method of evaluating packing properties of molding material of thermosetting resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply determine packing properties of a molding material of a thermosetting resin by using a mold wherein a recessed part provided in each of a plurality of cavities is formed as a blind alley and each vent part different in thickness is provided in each cavity. SOLUTION: A recessed part 5 forms a blind alley of each cavity 4 for a molded article, which evaluates packing properties. Further, each vent part 8 different in thickness is provided in each cavity 4. The recessed part 5 forming the blind alley, which is described herein, means that a recessed part has neither a gas vent nor an ejector pin provided in each cavity 4 and that a recessed part does not allow air and gas evolved at the time of setting of a resin to be discharged through a mold comprising the recessed part 5. As the recessed part 5, for example, the one whose sectional area is one-third to one-sixth of a cavity main body and whose occupied area is 10-40% of the whole area can be used. Furthermore, as the vent part 8, the one having 0-100μm, preferably, 30-70μm in thickness can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filling property evaluation method for molding a thermosetting resin molding material.

[0002]

2. Description of the Related Art Conventionally, the filling property of a thermosetting resin molding material is effective only in the injection molding and the transfer molding only by visually observing a molded product obtained by a mold actually used. In particular, in the case of a molded product having a complicated shape, it was very difficult to judge the filling property by visual observation. Since only qualitative judgments can be made and the judgments differ depending on the measurer, establishment of a method capable of making quantitative judgments has been desired.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of various studies in order to establish a conventional method for evaluating the filling property, which could only be judged qualitatively. It is to provide a method for evaluating the filling property of a thermosetting resin molding material that can be quantitatively determined.

[0004]

SUMMARY OF THE INVENTION The present invention is a mold having a plurality of cavities, in which recesses are provided in these cavities, and the recesses are used as blind alleys, and the vents having different thicknesses are provided in the respective cavities. The present invention relates to a method for evaluating the filling property in the molding of a thermosetting resin molding material, which is characterized by molding using a mold provided with.

In the mold used in the present invention, a cavity is provided with a concave portion, and this concave portion serves as a blind alley and has a certain depth. A plurality of cavities are preferably provided at regular intervals from the sprue. As a result, the gas is likely to stay in the dead end portion of the bag, which makes it easy for differences in filling properties to appear. In addition, the pressure difference is generated sequentially by setting a constant interval from the sprue to each of the cavities, and by considering the actual molded product, by providing a vent with a different thickness, it is possible to determine the difference in filling properties remarkably. You can

The concave portion which is a dead end as referred to herein means
In each of the cavities, a gas vent and a protruding pin are not provided, which means a concave portion from which air or gas generated during curing is not discharged from the concave portion through the mold. The recess has, for example, a cross-sectional area of 1/3 to 1/6 of the cavity body and an occupied volume of 10-4 of the whole.
0% can be used. The thickness of the vent portion is 0 to 100 μm, preferably 30 to 7
Those of 0 μm can be used. In addition, 100μ
When it exceeds m, a pressure drop is likely to occur in the cavity, which is not preferable for the filling property evaluation method.

In the case of injection molding, for example, a mold as shown in FIG. 1 is adopted as such a mold. The mold will be described below. FIG. 1 is a state in which the mold is clamped, (a) is a sectional view, and (b) is a plan view of a mold opening surface of a movable side mold plate. (1) is a fixed-side template, and (2) is a movable-side template. (3) is a sprue, (4) is a cavity of a molded product for evaluating the filling property, (5) is a concave portion which is a hollow path of the cavity, (6) is a protruding pin (only one cavity side is shown), (7) ) Is the protruding plate,
(8) is a vent portion with different thickness provided in each cavity. The plurality of cavities are arranged at regular intervals based on the sprue, and each cavity (4) is provided with a recess (5) at the center of the bottom. It is preferable that the position of the concave portion forming the blind alley is separated from the position of the gate, and is usually provided at the bottom of the cavity (as viewed from the mold opening surface).

FIG. 2 shows the molded product taken out. As can be seen from FIG. 2, the concave portion of the cavity having a certain depth appears as a protruding portion in the molded product, and the filling property can be quantitatively determined by measuring the filling degree of this portion. The degree of filling is measured by determining the volume of the protruding portion of the molded product, the bottom surface, the area of the flat portion, the distance from the upper surface of the protruding portion to the filling position, and the like. In addition, since the molding pressure transmission tends to be better as it is closer to the sprue, considering the distance from the sprue, and providing a vent part with a different thickness assuming the actual molded product, the filling property is significantly different. Can be determined.

The feature of this mold is that the cavity shape of the mold is suitable for evaluation of the filling property of the molding material, but the filling property is deliberately lowered by providing a concave portion which is a blind path. Moreover, since the mold shape and structure are simple, it is possible to easily make a quantitative judgment of the filling property.

[0010]

【Example】

<< Example 1 >> Using a phenolic resin molding material A having a relatively poor filling property, injection molding was performed under the following molding conditions,
When the molding was stable, one shot of the molded product was sampled. (Molding conditions) Mold temperature: 175 ° C. Cavity shape: 40 × 20 × 15 mm, 6 cavities (concavity on bottom of cavity: 20 × 10 × 10 mm) Vent shape: Cavity number 1 to 15 × 5 mm × 70 μm Cavity number 4 × 6 15 × 5mm × 30μm Length between sprue / gate and between gate / gate: 50mm Injection molding machine: Matsuda Mfg. 35 ton injection molding machine Real injection time: about 5 seconds Curing time: 50 seconds Each sample of molded product The area of the bottom surface of the protruding portion (for one shot) was measured, and the total sum of the samples was obtained.

Example 2 A phenol resin molding material B having a relatively good filling property was used, and the measurement was carried out under the same conditions as in Example 1. The results are shown in Table 1.

[0012]

[Table 1]

Table 1 shows the total sum of the bottom surface areas obtained in Examples 1 and 2 in comparison with the visual results. The filling property of Example 1 is inferior to that of Example 2, and there is a correlation with the visual judgment. Further, in the material used this time, the cavities number 1 to 3, that is, the vent portion having a thickness of 70 μm has a better filling property. From this,
It can be seen that this method is very effective as a quantitative evaluation method of filling property.

[0014]

According to the method of the present invention, as described above, by using a mold having a specific shape, it is possible to make filling in a more difficult direction (direction in which the filling property becomes worse) than in ordinary molding. Therefore, the filling property can be quantitatively evaluated. Further, since it is a simple evaluation method, it can be evaluated in a short time, the number of man-hours for measurement is prevented from increasing, and it is extremely effective for research, development, and evaluation of thermosetting resin molding materials.

[Brief description of drawings]

FIG. 1 is a mold (one example) used in the present invention, (a) is a cross-sectional view of a mold closed state, and (b) is a plan view seen from a mold opening surface.

FIG. 2 is a plan view, (b) is a front view of a molded product (completely filled state) obtained by using the above mold.
(C) is a side view

[Explanation of symbols]

 1 Fixed-side mold plate 2 Movable-side mold plate 3 Sprue 4 Cavity 5 Recessed portion 6 Ejection pin 7 Ejection plate 8 Vent portion 11 Molded product 12 Sprue portion 13 Runner portion

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29C 45/34 9268-4F B29C 45/34 // B29K 101: 10

Claims (2)

[Claims] 1. A mold having a plurality of cavities, concave parts provided in these cavities, and the concave parts being a blind alley, and a mold having a vent part having a different thickness in each of the cavities. A method for evaluating the filling property in molding of a thermosetting resin molding material, which comprises molding. 2. The volume occupied by the concave portion of the cavity is 10 to 40% of the entire cavity, and the thickness of the vent portion provided in each cavity and having a different thickness is 0 to 100 μm.
The evaluation method according to claim 1, wherein