JPH0625298B2 - Unsaturated polyester resin molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an unsaturated polyester resin molding material having improved molding processability (particularly filling property) due to the effect of increasing the viscosity during heating and melting.

[Conventional technology]

Unsaturated polyester resin molding materials are excellent in electrical characteristics such as arc resistance and tracking resistance, heat resistance, and dimensional stability, and are relatively low in price. Relay bases, automobile parts Used for applications such as plug pipes and coil caps.

This molding material comprises an unsaturated polyester resin, an inorganic or organic filler, and a trace amount of additives such as a release agent, a curing agent, and a coloring agent.

A molding material mainly containing an inorganic filler has excellent electrical characteristics, dimensional stability, etc., but has a drawback that the melt viscosity at the time of molding becomes low and the filling property is deteriorated depending on a molded product.

As a method for improving such a defect, a method of blending ultrafine particle silicon oxide, blending various thickening agents, blending an organic filler such as wood powder, etc. has been carried out.

However, in the case of blending ultrafine particle oxygen silicon, the workability at the time of manufacturing a molding material may be extremely deteriorated, the moisture resistance may be deteriorated, and the cost may be increased. The composition of the thickener is
Releasability is reduced during molding. In addition, when the organic filler is mixed, the moisture resistance and the like of the molded product deteriorate.

Both methods have new drawbacks, and further improvement has been desired.

[Problems to be Solved by the Invention]

The object of the present invention is to provide an unsaturated polyester resin molding material excellent in molding property such as heat resistance, dimensional stability and moisture resistance and molding processability without deteriorating the handling workability at the time of manufacturing a molding material. To provide.

[Means for Solving the Problems]

As described in the claims, the present invention relates to an inorganic filler-based unsaturated polyester resin molding material, in which fibrous and sepiolite, which is a clay mineral having a channel structure, is blended as a part of the inorganic filler. It is about materials. The unsaturated polyester resin molding material is obtained by heating and kneading an unsaturated polyester resin, a filler (mainly inorganic), a reaction initiator (peroxide), a release agent, a pigment, and a flame retardant, etc. The molding material is made of particles.

The unsaturated polyester resin is usually synthesized from a polyhydric alcohol (propylene glycol or the like), a saturated acid (phthalic acid) and an unsaturated acid (fumaric acid), and used in a prepolymer state which is fluidized by heating. As the inorganic filler, fine powder materials such as calcium carbonate, talc, mica, aluminum hydroxide, and clay, or fiber materials such as asbestos and glass fiber are used, but these are improved in surface hardness, flame retardant, and strength. It is added for the purpose of improving the quality of molded products such as improvement and improving moldability.

The blending ratio of the unsaturated polyester resin and the inorganic filler in the present invention is 280 to 350 parts by weight of the inorganic filler with respect to 100 parts by weight of the resin, and there is a wide range of blending ratios because the amount of sepiolite added is Is related to

That is, since sepiolite itself has a considerably large specific surface area and oil absorption amount, it has a property of absorbing resin or decreasing fluidity due to increase in viscosity. Therefore, it is necessary to increase the resin addition ratio as the blending ratio increases.
As a result of evaluating the actual moldability, the blending ratio of the present invention is appropriate in view of the balance between the fluidity of the molding material and the viscosity at the time of heating and melting.

The sepiolite used in the present invention is preferably in the form of fibers or powders having a size of 3 mm or less from the viewpoints of dispersibility at the time of producing a molding material and thickening effect at the time of heating and melting in the molding step.

In addition, it is appropriate to use a twin-screw extruder or a heating roll for manufacturing the molding material.

[Action]

Sepiolite, as shown in one example in Table 1,
An inorganic fiber material containing O ₂ and MgO as its main components, which is apparently fibrous or powdery, has a channel structure, and has a relatively large specific surface area and oil absorption.

Regarding the thickening effect of sepiolite, according to the fact that it absorbs a resin component because of its large oil absorption and specific surface area, and that it contains MgO, CaO, etc., which give a thickening effect to unsaturated polyester resins, as a component. Conceivable.

Also, it has a good effect on the filling property of the finely-shaped portion of the molded product, which is considered to have the effect of absorbing the gas content contained in the molding material or occluded during molding due to its channel structure. There is.

Sepiolite is produced in China, the United States, Turkey, etc., but domestic commercial products include "Milcon" manufactured by Showa Mining Co., Ltd.

With respect to the addition amount, if the addition amount is too small, the original taste is not exhibited, and if the addition amount is too large, the material flow is hindered.
It is in the range of 10 to 100 parts by weight with respect to 0 parts by weight.

〔Example〕

The compounds shown in Table 2 were melt-kneaded on a hot roll to obtain a molding material.

Example 1 is an example in which a part of calcium carbonate was replaced with powdery sepiolite (Milcon P) in Comparative Example 1 which is one of conventional formulations, but the material heating melting torque ( 150 ° C. Brabender measurement) was observed, and the moisture resistance characteristics (boiling insulation resistance value) were equal or higher.

Example 2 is an example of the use of fibrous sepiolite (Milcon SS), in which the ultrafine silicon oxide is substituted in Comparative Example 2 which is a conventional formulation. However, application of sepiolite showed an increase in heating and melting torque. In addition, no remarkable decrease in boiling insulation resistance is observed as in the case of the ultrafine silicon oxide application material.

Regarding actual moldability, injection molding, compression molding, etc. were carried out. However, compared to the comparative example, the filling property was improved in the shape portion such as the "rib" or "boss" shape tip portion with poor degassing. It was

[Effects of the Invention] In general, an inorganic filler-based molding material has excellent quality in terms of molded product characteristics, but tends to be poor in molding processability.

The cause is that the heating and melting torque during molding is low, and it is difficult to discharge the gas component in the molding material and the air in the molding die,
Alternatively, it is considered that it is difficult for the molding material itself to absorb a part of the gas component.

By using sepiolite as a part of the inorganic filler as in the present invention, from its thickening effect and channel structure, the molding processability is good, and the molding material has the same or more molded product characteristics as the use of a general inorganic filler. Can be obtained.

Claims (1)

[Claims] 1. A total of 280 to 350 parts by weight of a total inorganic filler is mixed with 100 parts by weight of an unsaturated polyester resin, and 100 parts by weight of the resin is sepiolite which is a fibrous clay mineral as a part of the inorganic filler. For 10-10
An unsaturated polyester resin molding material characterized by being blended in an amount of 0 part by weight.