JPH08244071A - Chargeability evaluating method for thermosetting resin molding material - Google Patents

Abstract

PURPOSE: To charge in a direction set difficult as compared with a normal molding case and to quantitatively evaluate the chargeability by providing a recess in a cavity and molding by using a mold in which the recess is formed as a blind alley. CONSTITUTION: A plurality of cavities 4 are disposed at a predetermined interval with a sprue 3 as a reference, and a recess 5 is provided at the center of the bottom of each cavity 4. The occupation volume of the recess 5 of the cavity 4 is set to 10 to 40% of the entire cavity 4. The position of the recess 4 as a blind alley is preferably separated from the position of the gate, and normally provided at the bottom of the each cavity 4. The recess 5 of the cavity 4 having a certain degree of the depth is represented as a protruded part at the molding, and the charging degree of the part is measured, thereby quantitatively judging the chargeability. The charging degree is measured by obtaining the volume of the protruded part of the molding, the areas of the bottom and the flat part, and the distance from the upper surface of the protruded part to the charging position.

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]

According to the present invention, a cavity is provided with a recess and molding is performed using a mold having the recess as a blind alley. Evaluation of filling property in molding of a thermosetting resin molding material. It is about the method.

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, by setting a constant interval from the sprue to each of the plurality of cavities, a pressure difference is sequentially generated, and it is possible to more significantly determine the difference in filling property.

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.

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 narrow path of the cavity, (6) is a protruding pin (only one cavity side is shown), (7) ) Is the protruding plate. 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 recess, which is the dead end, is far from the position of the gate, and is usually the bottom of the cavity (as seen from the mold opening surface).
It is provided in.

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, it is possible to judge the filling property in consideration of the distance from the sprue.

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 (recess on cavity bottom: 20 × 10 × 10 mm) Length between sprue / gate and between gate / gate: 50 m
m Injection molding machine: 35-ton injection molding machine manufactured by Matsuda Seisakusho Co., Ltd. Real injection time: about 5 seconds, about 10 seconds Curing time: 40 seconds Measure the area of the bottom surface of the protrusion of each sample (1 shot) of the molded product, The sum of each sample was calculated.

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. From this, it is understood 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) Side view

[Explanation of symbols]

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

Claims (2)

[Claims] 1. A method for evaluating the filling property in the molding of a thermosetting resin molding material, which comprises forming a recess in a cavity and molding the mold using the recess as a blind alley. 2. The evaluation method according to claim 1, wherein the occupied volume of the concave portion of the cavity is 10 to 40% of the whole cavity.