JPH0848854A - Phenolic resin molding material - Google Patents

Abstract

PURPOSE:To obtain a phenolic resin molding material of which both its flow and melt torque are improved, thus its filling properties and mold fogging becomes better and the molded products can maintain and/or increase their characteristics. CONSTITUTION:This phenolic resin molding material is prepared by admixing 0.3-0.7wt.% of a substance boiling at 80-150 deg.C, for example, methyl ethyl ketone, toluene, water or propanol to a resin composition comprising, as essential components, 100 pts.wt. of a phenolic resin and 100-200 pts.wt. of glass fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass fiber-filled phenolic resin molding material having a good filling property during molding and good cloudiness in a mold.

[0002]

2. Description of the Related Art Conventionally, a high-viscosity phenol resin has been used to improve the filling property and mold haze of glass fiber-filled phenol resin molding materials, or the flow has been shortened in the process of molding materials by short flow, Alternatively, it has been attempted to increase the melting torque of the molding material at the time of molding by using both of these means, but due to the decrease in the flow of the molding material, it becomes difficult to apply it to large molded products and There were also problems such as hardening of the.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a glass fiber-filled phenolic resin molding material which has good filling properties and does not cause cloudiness in the mold without reducing the flow of the molding material.

[0004]

The present invention relates to a glass fiber-filled phenolic resin molding material characterized in that the molding material contains 0.3 to 0.7% by weight of a substance having a boiling point of 80 to 150 ° C. Is. 80-1 used in the present invention
Examples of the substance having a boiling point of 50 ° C. include various liquid substances such as methyl ethyl ketone, methyl isobutyl ketone, water, toluene, xylene, ethylene glycol and propanol. In particular, methyl ethyl ketone, toluene, water and propanol are preferable.

[0005] As what influences the filling property of the molding material,
The flow and torque at the time of melting can be mentioned. The larger the two points, the better the filling property. In addition, mold fogging tends to occur when the filling property is poor, but when the filling property is poor, this is a substance that causes a gap between the molten material and the surface of the mold cavity to cause mold fogging there. This is because the (mainly low molecular weight component) remains attached.

On the other hand, if the filling property is good, a gap between the molten material and the surface of the mold is less likely to occur, and the low molecular weight component is less likely to adhere to the surface of the mold. Further, even if the low molecular weight component adheres, the material comes into intimate contact with the mold surface. Therefore, by incorporating the low molecular weight component into the molding material at each molding cycle, it is possible to suppress the clouding of the mold.

From the above knowledge, mold fogging is closely related to the filling property, and improving the filling property also prevents the mold fogging. In the conventional technique, it was difficult to make the flow and torque at the time of melting compatible with each other, but the present invention solves this problem.

[0008]

According to the present invention, a molding material having a good flow and a high melting torque can be obtained by containing 0.3 to 0.7% by weight of a substance having a boiling point of 80 to 150 ° C. in the molding material. I found what I could do. In particular, it is effective for a material having a small oil absorption amount such as glass fiber as a filler, and the melt viscosity of the material tends to decrease. 80-1
A molding material containing a substance having a boiling point of 50 ° C. has a good flow and a high melting torque, but the effect is not sufficiently exhibited at less than 0.3% by weight, and a molding product at 0.7% by weight or more. The molding shrinkage rate of No. 1 increases, causing a problem of dimensional accuracy. Therefore, the preferred content of such a substance is 0.
3 to 0.7% by weight.

The boiling point of the substance to be blended is 150 ° C.
If it is larger, this component tends to remain in the molded product,
There are drawbacks in practical use due to defects such as deterioration of thermal characteristics and dimensional accuracy. On the other hand, when the temperature is 80 ° C. or lower, it is likely to evaporate during the production of the molding material or during the storage, and the effect due to the compounding of the substance often disappears.

[0010]

EXAMPLES The raw materials shown in Table 1 were heat-kneaded with a mixing roll in a predetermined composition and pulverized to produce a molding material. The spiral flow of the obtained molding material and the melting torque by Labo Plastomill of Toyo Seiki Co., Ltd. were measured. Then, a test piece (JIS K 6911) was molded by transfer molding at 175 ° C. for 40 seconds. With this test piece, the shrinkage rate during molding was measured. In addition, moldability by injection molding (fillability, mold haze) was evaluated. Table 1 shows the results.

[0011]

[Table 1]

As is clear from the examples and comparative examples, the molding materials according to the examples of the present invention have a high flow rate and a high melting torque, and the filling property and the mold fog are also good. On the other hand, in Comparative Example 1, since the content of water (boiling point 100 ° C.) is as small as 0.1% by weight, the effect of improving the melting torque is small, and the effect of improving the moldability is almost negligible. In Comparative Example 2, since the water content is as large as 0.9% by weight, the flow rate is high, the melting torque is high, and the moldability is good. There is a drawback such as deterioration, which is a problem in practical use.

[0013]

INDUSTRIAL APPLICABILITY According to the present invention, by adding a small amount of a substance having a boiling point of 80 to 150 ° C. to a glass fiber-filled phenolic resin molding material, the flow is improved and the melting torque is improved. The cloudiness of the mold is improved.
Therefore, the characteristics of the molded product can be maintained and improved, and molding troubles can be improved, which is suitable as an industrial phenol resin molding material.

Claims (1)

[Claims] 1. A compounding composition containing 100 to 200 parts by weight of glass fiber as an essential component relative to 100 parts by weight of a phenol resin, and 0.3 to 0.7 of a substance having a boiling point of 80 to 150 ° C.
A phenol resin molding material, characterized in that the content is wt%.