JPH0711149Y2 - Resin impregnated fiber sheet molding material - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a resin-impregnated fiber sheet (hereinafter referred to as "SMC") molding material. Specifically, it accelerates the heat formation of the outer layer portion in the SMC manufacturing process to cure it. The present invention relates to an SMC molding material that shortens the time and has improved handling workability such as peelability of a protective film.

(Prior art and its problem) Conventionally, in the manufacturing process of SMC, after the glass fiber is impregnated with the resin compounding composition, the protective film covering the SMC surface is easily peeled from the SMC layer surface, and the stickiness due to the touch is caused. It took a long time to cure (age) before it could be transferred to the next press molding step, which was inefficient.

In order to solve the above-mentioned problems, the aging time has been shortened by increasing the amount of a commonly used thickener, or by adding a thickener only to the outer layer portion. However, under certain aging conditions, there are problems such as over-curing of the SMC as a whole, and partial curing of the SMC, and in the latter case, the thickener mixed in the outer layer part migrates to the inner layer part, which causes SMC There was a problem that the thickening effect of the surface layer was poor.

(Means for Solving the Problems) The present invention is to solve the above problems, and its gist is to provide an outer layer portion in an SMC having a three-layer structure obtained by impregnating glass fiber with an unsaturated polyester resin compounding composition. 2-layer SMC
A resin-impregnated fiber sheet molding material in which the resin mixture composition in the inside is mixed with magnesium oxide having a higher activity than magnesium oxide in the resin mixture composition of the SMC in the inner layer part to accelerate the thickening rate of the SMC in the outer layer part. Is.

Hereinafter, embodiments of the present invention will be specifically described.

FIG. 1 is a side sectional view showing the SMC molding material of the present invention, and FIG.
The figure shows a side cross-sectional view of a conventional SMC molding material.

SMC to be placed in the inner layer in the present invention (hereinafter referred to as "inner layer SMC")
The resin compounding composition of (1) is prepared by adding a thickening agent, a feel and other additives to an ordinary unsaturated polyester resin, and the thickening agent in the resin compounding composition is a magnesium oxide having a low activity. (Hereinafter referred to as “low activity MgO”),
The iodine adsorption amount [I (mg) / MgO (g)] is 20 mg / g.

On the other hand, the thickener in the resin compound composition of SMC (hereinafter referred to as “outer layer SMC”) to be arranged in the outer layer portion is magnesium oxide having high activity (hereinafter referred to as “highly active MgO”),
The amount of iodine adsorbed is 25 to 30 mg / g.

That is, the activity of high activity MgO in the outer layer SMC is 1.3 to 1.5 times that of low activity MgO in the inner layer SMC.

Highly active MgO has a scaly shape and relatively large primary particles, but since it does not form aggregates, it has high iodine adsorption and high activity.

On the other hand, low-activity MgO has a small primary particle but easily aggregates into a large particle, so that it has a lower iodine adsorption amount and a lower activity than the high-activity MgO.

The inner layer SMC and the outer layer SMC used in the present invention are obtained by impregnating 30% by weight of chopped roving glass fiber with 70% by weight of a resin composition having the following composition.

<Blending content> Blending amount (parts by weight) Unsaturated polyester resin ………………………… 80 Low shrinkage resin (polystyrene solution) ……………… 20 Catalyst (t-butyl peroxybenzoate) 1 Internal mold release agent (zinc stearate) …………………… 5 Filler (calcium carbonate) …………………… 120 Thickener (magnesium oxide) ………… 0.4 to 0.6 Pigment …… ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… of the resin ’s composition The product of the present invention is obtained by laminating the prepared inner layer SMC, and MgO is blended in an amount of 0.4 to 0.6 parts by weight per 100 parts by weight of the resin component as described above.

Outer layer SM composed of 0.4 parts by weight of highly active MgO as a thickener
The product of the present invention shown in Fig. 1 obtained by sandwiching the inner layer SMC2 composed of 0.4 parts by weight of low activity MgO between the two layers of C1 and 0.4 parts by weight of low activity MgO alone as a thickener. Comparing with the conventional product shown in FIG.
The product of the present invention has been matured at 40 ° C for 1 to 1.5 days, and the outer layer S
The protective film 3 could be easily peeled off from the MC1, and the surface of the outer layer SMC1 after peeling disappeared. However, the conventional product is similar to the above in terms of peelability and stickiness of the film 3. It took 4 days until it became.

(Effects of the Invention) Since the present invention is configured as described above, the following effects are achieved.

That is, the present invention is an inner layer SMC containing low activity MgO in the middle of two layers of outer layer SMC in which high activity MgO is mixed to accelerate the thickening rate.
Since it is sandwiched between layers, low activity MgO
Compared to the SMC laminate containing only the above or the amount of the thickener added over the entire SMC layer, or the one containing the thickener only in the outer layer, curing may proceed excessively or the viscosity may be insufficient. The effect that the SMC can be efficiently manufactured with good handling workability, because the aging time until it can be easily peeled off from the protective film, that is, until the surface becomes non-sticky can be greatly reduced to about 1/3 to 1/4. Is played.

[Brief description of drawings]

FIG. 1 is a side sectional view showing the SMC molding material of the present invention, and FIG.
The figure shows a side cross-sectional view of a conventional SMC molding material. 1 ... Outer layer SMC, 2 ... Inner layer SMC

Claims (1)

[Scope of utility model registration request] 1. An SMC having a three-layer structure obtained by impregnating glass fibers with an unsaturated polyester resin compounding composition, wherein the resin compounding composition in the SMC of two layers of the outer layer is the resin compounding composition of the SMC of the inner layer. A resin-impregnated fiber sheet molding material that contains magnesium oxide, which has higher activity than magnesium oxide in the product, to accelerate the thickening rate of the outer layer SMC.