JPH0678480B2 - Unsaturated polyester resin molding material - Google Patents

Description

TECHNICAL FIELD The present invention relates to an unsaturated polyester resin molding material. More specifically, the present invention relates to an unsaturated polyester resin molding material having no color unevenness, excellent gloss, and good dimensional accuracy and smoothness.

(Prior Art) An unsaturated polyester resin molding material has been conventionally known as a BMC injection material, and has been used as a molding material for electric / electronic devices and parts thereof, containers and the like.

Regarding this unsaturated polyester resin molding material, in order to impart low shrinkage, styrene monomer is blended,
It is also mixed with additional components such as inorganic fillers and reinforcing materials. Further, polystyrene or polyethylene is further blended with these materials, and these blending components are wet premixed and mixed.

(Problems to be Solved by the Invention) However, such a conventional premix unsaturated polyester resin molding material has problems that the color unevenness of the molded product is severe and the luster is lacking.

Therefore, in the case of a unsaturated polyester resin molding material containing a styrene monomer and premixed,
It has been strongly desired to realize a molding material which retains the characteristic low shrinkage, that is, dimensional stability, eliminates such color unevenness, improves gloss, and has good surface smoothness.

The present invention has been made in view of the circumstances as described above, eliminates the disadvantages of the conventional premix molding material, has no color unevenness, is excellent in gloss, and is unsaturated with good dimensional accuracy and smoothness. It is intended to provide a polyester resin molding material.

(Means for Solving the Problems) As a means for solving the above problems, the present invention provides an unsaturated polyester resin material containing a styrene monomer,
Disclosed is an unsaturated polyester resin molding material, which is characterized by blending polyethylene and polymer polystyrene together with styrene / ethylene / propylene / styrene copolymer and polycaprolactone mixed with styrene monomer.

As the unsaturated polyester resin, bisphenol type,
Appropriate ones that have been used up to now can be used for the unsaturated polyester resin such as phenolic resin, and the unsaturated polyester resin (A) contains styrene monomer (SM) in a weight ratio (A / SM). It is contained at a ratio of 80/20 to 50/50, preferably about 12 to the total amount of molding material.
Add ~ 20% by weight.

If the amount of the unsaturated polyester resin material is too large, the dimensional stability and smoothness will be poor, and it will be difficult to prevent color unevenness and improve gloss. On the contrary, even if the blending amount is small, improvement of these characteristics cannot be expected.

For styrene-ethylene-propylene-styrene copolymer (B) mixed with styrene monomer (SM) as a blending component, and for polycaprolactone (C), polyethylene (D) and high molecular polystyrene (E) mixed with styrene monomer in the same manner , B / SM = 10/90 to 40/60 C / SM = 10/90 to 50/50 D / SM = 100/0 E / SM = 100/0 by weight ratio with styrene monomer It is preferable that B = 2 to 10% by weight, C = 0.1 to 0.5% by weight, D = 1 to 3% by weight, and E = 0.5 to 1.5% by weight, based on the weight of the molding material. These compounding ingredients (B)
When (D) and (E) are used together with (C) and (C), color unevenness is suppressed, gloss is improved, dimensional accuracy and smoothness are particularly excellent.

In addition, a filler, a reinforcing material, and the like can be appropriately added to the molding material of the present invention.

As the filler, an inorganic filler is preferable, and calcium carbonate, aluminum hydroxide or the like can be used. As the reinforcing material, for example, glass fiber, silica, talc, etc., and further, a curing agent composed of a peroxide such as tertiary butyl perbenzoate (TBPB) or benzoyl peroxide (BPO), zinc stearate or A release agent such as calcium stearate, a thickener comprising an aluminum chelate such as MgO, ethyl acetoacetate, and aluminum diisopropylate can be added.

The unsaturated polyester resin molding material thus obtained can be subjected to injection molding, compression molding, cast molding or the like under the conditions of a temperature of 120 to 180 ° C. and a pressure of about 50 to 150 kg / cm ² .

(Operation) In the present invention, by blending a low-shrinking agent containing a styrene monomer with polyethylene and high-molecular polystyrene not containing the low-shrinking agent, color unevenness is suppressed, gloss is obtained, and dimensional accuracy and smoothness are improved. It is possible to realize a good unsaturated polyester resin molding material.

(Examples) Examples 1 to 6 Using hydrogenated bisphenol unsaturated polyester resin,
An unsaturated polyester resin molding material having the blending ratio shown in Table 1 was produced.

Using the obtained molding material, temperature 155 ℃, pressure 100 kg / cm ² ,
Molding was performed for 90 seconds to obtain a flat plate molded product.

This molded product was evaluated for mold shrinkage, gloss, smoothness and color unevenness. This evaluation was performed as a perfect score of 5. Table 1 shows the result.

As is clear from comparison with Comparative Examples described later, in the case of the examples of the present invention, the molding shrinkage has a shrinkage rate of 0 ± 0.004.
%, And excellent effects can be obtained in terms of suppressing gloss, smoothness, and color unevenness.

Comparative Examples 1 to 5 In the case of using only the low-shrinking agent premixed with styrene monomer, the molding material having the composition shown in Table 1 was manufactured, and the molded product was evaluated in the same manner as in the examples.

The results are shown in Table 1.

The molding shrinkage was large and the color unevenness was severe.

(Effect of the Invention) As described in detail above, the present invention provides an unsaturated polyester resin molding material having no color unevenness, gloss, and good dimensional accuracy and smoothness.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08L 25:06)

Claims (3)

[Claims] 1. An unsaturated polyester resin material containing a styrene monomer, wherein polyethylene and high molecular polystyrene are blended together with a styrene / ethylene / propylene / styrene copolymer and a polycaprolactone mixed with a styrene monomer. Unsaturated polyester resin molding material. 2. An unsaturated polyester resin material having a weight ratio of unsaturated polyester to styrene monomer of 80/20 to 50/50 is blended in an amount of 12 to 20% by weight based on the total amount of the molding material. The unsaturated polyester resin molding material according to 1). 3. A styrene / ethylene / propylene / styrene copolymer and a polycaprolactone mixed with a styrene monomer are used in an amount of 2 to 10 with respect to the total amount of the molding material.
The unsaturated polyester resin molding material according to claim (2), wherein the unsaturated polyester resin molding material comprises 0.1 to 0.5% by weight, 1 to 3% by weight of polyethylene, and 0.5 to 1.5% by weight of high molecular polystyrene.