JPS60101148A - Production of thermosetting molding material - Google Patents

Abstract

PURPOSE:To increase the quantity to be discharged in a subsequent kneading stage by forming a less bulky mixture, by incorporating a glass fiber having a specified fiber length with a thermosetting resin. CONSTITUTION:5-75wt% glass fiber having a fiber length of 0.3-2mm. and other additives such as a filler, a catalyst, etc. are mixed with a thermosetting resin such as dillyl phthalate resin, phenolic resin or epoxy resin in a ribbon blender or a Henschel mixer. The resulting mixture having a high bulk density is kneaded in a screw extruder and extruded to obtain a thermosetting molding material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a process for mixing various raw materials as a pre-crosstalk process in the production of thermosetting molding materials. The present invention provides a method for reducing the bulk of a J-Mo compound.

By reducing the hypertonicity of the mixture, it is possible to increase the amount of mixture per batch that can be mixed by a mixer with a constant volume. Furthermore, when mixing is performed using a screw extruder, the amount of the mixture conveyed per screw = -1 rotation can be increased, resulting in an increase in the amount of discharge.

The present invention brings about such effects.

Among various thermosetting molding materials, for example, diallyl phthalate resin molding materials often contain a large amount of glass fiber, and in the DM-GE and DM-GF grades, the glass fiber content is 50%.
It is not uncommon for the weight to be close to the same. In addition, even in the case of phenolic resin molding materials, which have often used wood flour, asbestos, calcium carbonate, etc. as fillers, in recent years they have been considered as metal substitutes for automobile parts, taking advantage of their heat resistance and other characteristics. In order to obtain higher strength, dimensional stability, etc., materials filled with glass fibers have come to be used.

Conventionally, glass fibers of 3 to 6 types have been mainly used in such thermosetting molding materials. This length is well-balanced in terms of productivity in cutting the glass roving, ease of handling as a raw material for molding material, and fiber length required as a reinforcing material. It's the length. However, as thermosetting molding materials became highly filled with glass fibers, it became clear that such lengths had serious drawbacks in their manufacture. In other words, when mixing glass fibers, resin, and other necessary components (mold release agent, coloring agent, etc.) as a pre-kneading process, glass fibers of such length are untied and tangled, resulting in so-called Make a hairball,
Moreover, the apparent density of the fluff itself is low, resulting in a mixture that is extremely hypertonic as a whole. A disadvantage of this phenomenon is that the amount of mixture per batch is suppressed. Furthermore, even if such a mixture is supplied to a screw extruder, it is poorly penetrated, and a small discharge amount must be accepted. One possible solution to this phenomenon is to use very short glass fibers that do not form pilling.

However, short fibers of 0.3 trm or less do not have a sufficient reinforcing effect and the mechanical strength of the resulting molding material decreases. Additionally, if glass fibers with very strong convergence properties are used to prevent fibrillation during mixing, dispersion may become insufficient during the kneading process, or an abnormal load may be placed on the kneader. So this is also not desirable.

The present invention has been made to eliminate such problems, and aims to obtain a mixture with less hypertonicity by using 0.3 to 2 glass fibers.

This will be explained in detail below.

The type of resin is not limited in any way, and the present invention can be used to produce a molding material using a resin that is used in powder form. For mixing the various raw materials, a mixer such as a Bonpreter, Niter, Henschel, etc. is used, for example. In this step, glass fibers of 0.3 to 2 mm are mixed together with various other raw materials, and it is desirable that the fibers have a 1 to 2 tone and normal convergence. Although this product partially defibrates in the mixing process, it does not cause pilling or increase the hypertonicity of the mixture. Further, no problems occur in the next cross-wire step, and the mechanical strength of the obtained material is equivalent to that of using long glass fibers. The amount of M to be added can be arbitrarily selected between 5 and 75% by weight, but is preferably 10 to 70%. If it is less than 10%, the reinforcing effect will not be sufficient, and if it is more than 70%, problems such as moldability will occur. However, both the fiber length and the amount added are not limited to those described here.

The mixing process can be broadly classified into roll or screw extrusion (carried out using charcoal). As the screw extruder, a single screw extruder such as a co-kneader or a twin screw extruder is used.

The present invention is particularly effective in production using a screw extruder. In the production of thermosetting molding materials using an extruder, it would be an ideal situation if the capacity of the extruder could be fully utilized, but if the mixture supplied to the extruder has a high degree of hypertonicity, it would cause problems such as sulfur IJ, - Even if the rotational speed is set to the upper limit, only a very small amount of particles will be mixed in, and the amount of discharge will be much lower than the amount that can be kneaded. The discharge amount is determined by the hypertonicity of the mixture, which is far from an ideal operating condition. On the other hand, if the method according to the present invention is followed, the capabilities of the extruder, such as the plasticizing ability and extrusion ability, can be fully utilized, and it is extremely advantageous in terms of power efficiency.

After mixing, a molding material is obtained by a commonly used method such as extrusion granulation or pulverization.

Diaryl phthalate resin, polyester resin, phenol resin,
It is possible to efficiently produce thermosetting resin molding materials such as epoxy resins.

Next, Examples and Comparative Examples will be described together.

Example 1 and Comparative Example 1.2 Inphthalic acid-based unsaturated, Japanese polyester resin 80 weight Chichi: Diallyl phthalate prepolymer 20 #Calcium carbonate 285 Glass fiber 100 #Zinc stearate 10 N Dicumyl peroxide 5I Total 100 weight In the above formulation, the glass fiber was 1.5 rrrm (Example 1), 0.2 mm (Comparative Example 1), 6 mm (Comparative Example 2)
The high tensile strength of the mixture, the discharge amount in the screw extruder, and the bending strength of the obtained molding material were as shown in Table 1. Comparative Example 2 has low strength, and Comparative Example 3 has drawbacks such as extremely small discharge amount.

Table 1 Note) Mixer: 1004 kneader - 1o minute screw j, - Extruder: 2 screws (50 openings), 300 rpm Example 2,
Comparative Example 3 Diallyl phthalate prepolymer 100 Glass fiber 75 Calcium carbonate 20 Zinc stearate 25 # Dicumyl peroxide 2.5'1 Total 200 In the above formulation, glass fiber was added to a thickness of 1.5 mm (Example 2), 3M (Comparative Example 3) Hypertonicity of the mixture,
The discharge amount in the screw extruder and the bending strength of the obtained molding material were as shown in Table 2. Comparative Example 3 had a drawback that the discharge amount was extremely small.

Table 2 LE) 17t+total u%: 1001=I” 10
Minute screw extruder: Co-kneader (PR-46), 6
0rpm/item Sumitomo Bakelite Co., Ltd.

Claims (1)

[Claims] (1) Glass 9: Production of a thermosetting molding material reinforced with fibers, characterized in that the glass fiber length is 0.3 to 2. Method (2) Claim 1 in which the addition of glass fiber is 5 to 75% by weight
(3) The method for producing a thermosetting molding material according to Claim 1 or 2, wherein the mixing of glass fibers, resins, and other necessary components is carried out using a screw extruder.