JPH05147029A - Sheet molding compound and preparation of the same - Google Patents

Abstract

PURPOSE:To improve interface adhesion and workability by applying a compound on a fiber reinforcing material of a film, arranging the fiber reinforcing material, and combining the surface of another film coated with the compound. CONSTITUTION:A resin compound 3 from a resin tank 1 is applied with a docter knife 6 on the inner surface of a thermoplastic film 7. After a chopped glass strand 10 prepared by cutting a glass roving 8 with a roving cutter 9 is spread on the coated surface, a resin compound 5 from a resin tank 4 is applied using a non-contacting type coater 11 on the coated surface of the chopped glass strand 10 on which a chopped glass strand 13 is spread additionally. The resin compound 3 from a resin tank 2 is applied on the inner surface of a thermoplastic film 15 with a docter knife 14. The inner surfaces of the thermoplastic films 7, 15 are combined together to form a sheet using a defoaming- impregnation roller 16. The sheet produced is wound up with a winding roller 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new and useful sheet molding compound and a method for producing the same. More specifically, the present invention relates to a novel sheet molding compound having a multilayer laminated structure (hereinafter abbreviated as SMC) and a novel and useful production method of the SMC.

[0002]

2. Description of the Related Art As is well known, this type of SMC is such that a compound is applied to the inner surface of two thermoplastic films such as polyethylene and polypropylene, and a chopped glass strand is formed on one of the films. Manufactured by arranging a fiber reinforced material such as, and then aligning the compound coated surface of the other film with the fiber reinforced material surface, followed by defoaming / impregnation and winding into a roll. It is something.

The inventors of the present invention use the above-mentioned conventional technique to produce a specific SMC in which one SMC surface has a low specific gravity SMC and the other surface has a high strength SMC. And a method for producing a low specific gravity SMC molded product having a sandwich structure, in which the surfaces having the characteristics of the low specific gravity SMC of the SMC are superposed on the inner side and press-molded, and have a sandwich structure. I am applying for a patent. (See Japanese Patent Laid-Open No. 1-226311.)

[0004]

However, in the above-mentioned SMC, the surface having the characteristics of low specific gravity SMC contains a hollow lightweight filler (such as a glass balloon). Therefore, the surface is easily dried, and therefore, when the above-mentioned surfaces are stacked on the inside, there is a drawback in that the adhesiveness at the interface is likely to be poor, which inevitably causes a decrease in workability. As a result, the proposition of rationalizing workability cannot be met.

In addition, when press-molding is performed using SMC having such poor adhesion, peeling is apt to occur at the interface between planes having the characteristics of low specific gravity SMC, and as a result, it is obtained. There is a problem that the strength or rigidity of the molded product is significantly reduced.

[0006]

Therefore, the present inventors have
In view of the existence of such drawbacks of the prior art, in addition to the above-mentioned problems to be solved by the invention, as a result of intensive studies, a high strength SMC /
Sandwich structure type S with low specific gravity SMC / high strength SMC
It was found that MC can be manufactured collectively and reliably, and by doing so, the problems as described above can be solved satisfactorily, and the present invention is completed. Came to.

That is, the present invention is a compound containing no hollow lightweight filler on the inner surfaces of two thermoplastic films [hereinafter referred to as compound (A)]. ], The fiber reinforcing material is placed on the compound (A) of the one film, and the fiber reinforcing material surface is aligned with the coated surface of the compound (A) on the other film, A compound [hereinafter, referred to as compound (B)] further containing a hollow lightweight filler on the fiber reinforcing material of one of the films. ], And further, a fiber reinforcing material is arranged thereon, and a method for manufacturing a sandwich structure type SMC is provided.

[0008]

[Structure] The SMC manufacturing method of the present invention will be described in detail by showing one embodiment thereof with reference to the drawings.

First, FIG. 1 is a schematic view showing an example of the SMC manufacturing apparatus of the present invention. In the present invention,
First, the resin tank (1) and the resin tank (2) are charged with a so-called resin compound (3) such as unsaturated polyester resin and / or vinyl ester resin,
The resin tank (4) is charged with a so-called resin compound (5) such as unsaturated polyester resin or / and vinyl ester containing a hollow lightweight filler.

In the resin compound (3) and the resin compound (5), a curing agent, a release agent, a coloring agent, a shrinkage-reducing agent, a flame retardant, and a thickening agent may be further added, if necessary. An agent, a filler, a flake or fibrous reinforcing material, or other known and commonly used additives can be appropriately mixed.

Next, the resin compound (3) supplied from the resin tank (1) is applied to the inner surface of various thermoplastic films (7) such as polyethylene or polypropylene film by a doctor knife (6). The glass roving (8) and the chopped glass strands (10) obtained by cutting with a roving cutter (9) on the glass roving (8), and then the resin supplied from the resin tank (4). Compound (5)
Is applied to the sprayed surface of the chopped glass strand (10) with a non-contact coater (11), and the glass roving (8) is cut on it with a roving cutter (12) to obtain chopped glass. Sprinkle the strands (13).

Further, the resin compound (3) supplied from the resin tank (2) is applied to the inner surface of various thermoplastic films (15) such as polyethylene film by a doctor knife (14), Done 2
The inner surfaces of the thermoplastic films (7) and (15) are superposed on each other, made into a sheet by a defoaming / impregnating roll (16), wound by a winding roll (17), and aged, S of three-layer structure (sandwich structure)
It is to get MC.

A resin compound (3) is charged in the resin tank (4), or a resin compound (5) is charged in the resin tanks (1) and (2) so that the same kind of resin compound is used. , The target 3-layer SM
You can also get C.

Further, the number of roving cutters, resin tanks and / or non-contact type coaters is increased, and further,
It is also possible to obtain an SMC having a multilayer laminated structure. As the non-contact type coater used in the present invention, only typical ones are curtain coaters, shower coaters, sprayers, extruders, etc., in which the properties of the resin compound are used. It may be appropriately selected depending on (such as viscosity and fluidity).

[0015]

As described above, the novel SMC manufacturing method of the present invention uses the unique sandwich structure type SMC of high strength SMC / low specific gravity SMC / high strength SMC.
Since it can be prepared collectively and surely, one surface of one SMC, which was previously applied, has the characteristics of low specific gravity SMC, and the other surface has the characteristics of high strength SMC. The low specific gravity S, which was a drawback of certain SMCs
It solves the problem of adhesion failure at the interface between planes that have the characteristics of MC, and at the same time significantly improves the quality of the resulting lightweight and high-strength sandwich structure SMC molded product.
It can be improved.

[0016]

EXAMPLES Next, the present invention will be described with reference to Examples and Comparative Examples.
This will be described more specifically. In the following, "parts" means "parts by weight" unless otherwise specified. Each example is merely an illustration of one embodiment of the invention, and the invention is specifically described as:
It is not limited to these.

Example 1 Resin tanks (1) and (2) of an SMC manufacturing apparatus as shown in FIG. 1 were charged with a resin compound (A) as shown in Table 1, and a resin tank (4) was prepared. Then, the resin compound (B) as shown in the same table was charged.

The resin compound (A) supplied from the resin tank (1) was applied on the inner surface of the polyethylene film (7) by a doctor knife (6) in an amount of 400 g per square meter, and then, 1 inch long chopped glass strand ["RER 4630
-SM18 "[using glass roving manufactured by Nippon Glass Fiber Co., Ltd.]] (10)
After spraying in an amount of 500 g, on top of it, further,
The resin compound (B) supplied from the resin tank (4) was applied with a curtain coater (11) in an amount of 2,200 g per square meter, and further, 1 inch long chopped glass was applied thereon. Strands (13) were applied in an amount of 1,500 g per square meter.

Next, the resin compound (A) supplied from the resin tank (2) was applied on the inner surface of the polyethylene film (15) by a doctor knife (14) in an amount of 400 g per square meter, and the above-mentioned was performed. Street polyethylene film (7) and (15)
After defoaming and impregnating the inner surfaces of each other, they are wound into a roll and aged at about 50 ° C for 24 hours to obtain high strength SMC / low with a weight of 6,000g per square meter. Specific gravity SMC / high strength SMC,
A so-called sandwich type SMC was obtained.

Next, this SMC is set to 920 × 490 mm
When the sunroof housing of an automobile was molded as shown in FIG. 2 after cutting into the basic dimensions of No. 2, no so-called external defects such as blisters were observed, even fine dust.

The molding conditions at this time are as follows: mold temperature: upper mold = 146 ° C., lower mold = 142 ° C., pressurizing pressure = 450 tons, pressurizing time = 3 minutes, and The charge weight was 4.0 kg.

[0022]

[Table 1]

<< Footnote in Table 1 >>"PolylitePS-260" .... unsaturated polyester resin "Dainippon Ink and Chemicals Incorporated""Glass Balloon B37 / 2000" ... Sumitomo 3M
Product "Polyton PT-7234" ………… Coloring agent manufactured by Dainippon Ink and Chemicals, Inc. Zinc stearate ……………… Release agent manufactured by Dainippon Ink and Chemicals, Inc. "Kayabutyl B" …………………… Kayaku Akzo Co., Ltd.
Hardener “MgO-40” manufactured by Kyowa Chemical Co., Ltd. Thickener “RP-84” manufactured by Kyowa Chemical Co., Ltd. ) Thickening aid

COMPARATIVE EXAMPLE 1 A resin tank (18) of a conventional SMC manufacturing apparatus as shown in FIG. 3 was charged with a resin compound (B) as shown in Table 1, and a resin tank (20) was prepared. The resin compound (A) as shown in the same table was charged.

The resin compound (A) supplied from the resin tank (20) was removed by a doctor knife (24).
An amount of 400 g per square meter was applied on the inner surface of the polyethylene film (25), and 1 inch of chopped glass strands ["RER 46
30-SM18 "] (26) was applied in an amount of 1,500 g per square meter.

Next, the resin compound (B) supplied from the resin tank (18) is fed with a doctor knife (22).
The above-mentioned two polyethylene films (23) and (2) are coated on the inner surface of the polyethylene film (23) in an amount of 1,100 g per square meter.
The defoamed and impregnated sheets of 5) on top of each other were rolled up and rolled into a roll, and aged at about 50 ° C for 24 hours, and the polyethylene film (23) side has a low specific gravity S
A control SMC, which was MC and had the property of high strength SMC on the polyethylene film (25) side, and had a weight of 3,000 g per square meter was obtained.

After that, this SMC is changed to 920 × 49.
Two pieces were cut into a basic size of 0 mm, and the surfaces having the characteristics of low specific gravity SMC were placed inside, and the two pieces were stacked under the same conditions as in Example 1.

The surface of this SMC having the characteristics of low specific gravity SMC is very smooth and sticky because a large amount of hollow lightweight filler (glass balloon) floats up on the surface. There is no such thing, and moreover,
It was confirmed that a large number of circular blisters having a diameter of about 30 to 100 mm were generated in this molded product.

When the blister portion was cut out and observed, peeling occurred at the interface between the two SMCs (the interface between planes having the characteristics of low specific gravity SMC).

Next, from each of the molded products obtained in Example 1 and Comparative Example 1, a test piece having a size of 25 × 60 mm was cut out from the position as shown in FIG. A test piece was prepared.

For each test piece, the bending strength, J
Flexural modulus according to IS K-7203, and JI
The specific gravity according to SK-7112 was measured. The results are collectively shown in Table 2. The molded product of Comparative Example 1 has a large decrease in both flexural strength and flexural modulus due to internal peeling. However, it is apparent that the quality of the SMC of Example 1 is much more stable.

[0032]

[Table 2]

[0033]

Since the object of the present invention is that the SMC can be manufactured in a lump, until now, one surface of one SMC has characteristics of low specific gravity SMC and the other surface has a high strength SMC.
It has become possible to solve the problem of adhesion failure at the interface between planes having the characteristics of low specific gravity SMC, which is a drawback of a specific SMC that has the characteristics of. The quality of the thus obtained lightweight and high-strength sandwich structure SMC molded product can be significantly improved.

[Brief description of drawings]

1 is a view for explaining a method for manufacturing an SMC of the present invention,
It is a schematic structure figure (flow chart) of a device for SMC manufacture.

FIG. 2 is a schematic plan view showing a sunroof housing of an automobile.

FIG. 3 is a schematic configuration diagram (flow chart) for showing an apparatus for manufacturing a conventional SMC.

[Explanation of symbols]

1, 2 and 4 Resin tank 3 and 5 Resin compound 6 and 14 Doctor knife 7 Thermoplastic film 8 Glass roving 9 and 12 Roving cutter 10 and 13 Chopped glass strand 11 Non-contact coater 15 Thermoplastic film 16 Defoaming / impregnating roll 17 Scraping Roll 18 and 20 Resin Tank 19 and 21 Resin Compound 22 and 24 Doctor Knife 23 Thermoplastic Film 25 Thermoplastic Film 26 Chopped Glass Strand 27 Glass Roving 28 Roving Cutter 29 Defoaming / Impregnating Roll 30 Scraping Roll

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[Procedure amendment]

[Submission date] January 7, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // B29K 105: 06 B29L 9:00 4F

Claims (4)

[Claims] 1. A compound (A) is applied to the inner surface of two thermoplastic films, and a fiber reinforcement is disposed on the compound (A) of one of the heat-composable films. In the method for producing a sheet molding compound, the coated surface of the compound (A) on the other thermoplastic film is aligned with the surface of the compound (A) prior to aligning the coated surface of the compound (A) on the other thermoplastic film. A method for producing a sheet molding compound, which comprises coating the compound (B) on the fiber reinforcing material in the thermoplastic film and further disposing the fiber reinforcing material on the compound (B). 2. The production method according to claim 1, wherein the compound (A) does not contain a hollow lightweight filler. 3. The production method according to claim 1, wherein the compound (B) contains a hollow lightweight filler. 4. A sheet molding compound obtainable by the method according to claim 1.