JPH07112500A - Sheet molding compound molded product - Google Patents

Abstract

PURPOSE:To maintain the bending elastic modulus and bending strength of a molded product even with the content percentage of recycling power increased in the molded product. CONSTITUTION:This sheet molding compound consists of the first layer 11 which contains fiber reinforcing agent 13, thermosetting resin 14 and recycling power 16 of sheet molding compound molded product, and the second layer 12 which is formed in both the surfaces of the first layer 11 and contains the fiber reinforcing material 13 and the thermosetting resin 14, and does not contain the recycling power 16 of this sheet molding compound molded product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet molding compound molded product containing recycled powder.

[0002]

2. Description of the Related Art In recent years, waste treatment represented by scrapped vehicle shredder dust has become a social problem due to the reduction of landfill sites, and in combination with the enhancement of the global environmental protection movement, sheet molding compound (hereinafter referred to as SMC). Recycling) has become an urgent issue.

Therefore, in order to effectively use these SMC wastes, a sheet molding compound molded article containing a recycled powder obtained by crushing SMC wastes has been proposed (Abstracts of the 36th FRP Lecture Meeting. Takeda Yakuhin). Industrial Co., Ltd.). This contains a fiber reinforcing material such as glass fiber for improving strength, a thermosetting resin for bonding the fiber reinforcing materials, calcium carbonate and the recycled powder used in place of a part of calcium carbonate. is there.

[0004]

However, in the above-mentioned molded product, since the recycled powder is present near the surface of the molded product, the proportion of the fiber reinforced material near the surface is reduced accordingly and the bending elasticity is reduced. Rate and bending strength are low. As a result, the content rate of recycled powder in molded products was 2
As it is increased in the range of 0% or less, the flexural modulus and flexural strength of the molded product are significantly reduced.

Therefore, according to the present invention, even if the content of the recycled powder in the molded product is increased in the range of 25% or less by preventing the recycled powder from being present in the vicinity of the surface of the molded product, the flexural modulus and bending of the molded product are increased. It is a technical problem to provide a sheet molding compound molded product containing recycled powder capable of ensuring strength.

[0006]

The technical means (hereinafter referred to as the first technical means) taken in the invention of claim 1 in order to solve the above technical problems are a fiber reinforced material and a thermosetting material. First layer containing resin and recycled powder of sheet molding compound, and formed on both sides of the first layer, containing fiber reinforcement and thermosetting resin and containing recycled powder of sheet molding compound The second layer is not included.
Preferably, an inorganic substance such as calcium carbonate may be contained in the first and second layers.

Examples of the fiber reinforcement include glass fiber, and examples of the thermosetting resin include epoxy resin, unsaturated polyester resin, vinyl ester resin and the like.
Incidentally, a curing agent, a release agent, a coloring agent, a shrinkage reducing agent, a flame retardant, a thickener, a filler and other known additives can be added and mixed into the thermosetting resin.

Now, a method for manufacturing a sheet molding compound molded article containing the recycled powder according to the present invention will be described.

Recycled powder obtained by crushing SMC waste is mixed in a liquid thermosetting resin and stirred to form a thermosetting resin paste, and the thermosetting resin paste is applied on the inner surface of the thermoplastic film. . On the other hand, after applying a thermosetting resin paste containing no recycled powder on the inner surface of the thermoplastic film, the cut fiber reinforced material is sprinkled on the paste and resin containing no recycled powder on the inner surface of the thermoplastic film. Form a mixed layer with fiber reinforcement. Then, the inner surfaces of the two thermoplastic films are overlapped and impregnated and aged to obtain a sheet mold compound.

Finally, the sheet molding compound molded article of the present invention is formed by press-forming the resin layers containing the recycled powder of the two sheet mold compound sheets formed as described above in a state of being superposed on each other inside. To get

In order to solve the above technical problems, a second aspect is provided.
The technical means taken in the invention (hereinafter referred to as the second technical means) is to make the average particle diameter of the recycled powder contained in the first layer smaller than 1050 μm. The average particle size of the recycled powder is 19 to 800 μm.
Is desirable.

When the average particle size of the recycled powder is 1050 μm or more, it becomes difficult to mix the recycled powder with the thermosetting resin, which makes manufacturing difficult. Therefore, even if a molded product is manufactured, the recycled powder content is 2
In the range exceeding 5%, the flexural strength and flexural modulus become very low, and the molded product suffers from poor appearance such as blister.

[0013]

According to the first technical means, since the second layer containing no recycled powder is formed on both surfaces of the first layer containing recycled powder, the recycled powder exists near the surface of the molded product. However, the ratio of the fiber reinforcement present near the surface is increased as compared with the conventional technique, and the bending elastic modulus and bending strength of the molded product are improved. As a result, the bending elastic modulus and bending strength of the molded product can be maintained even if the content of the recycled powder in the molded product is increased within the range of not exceeding 25%. Therefore, more SMC waste can be effectively utilized than in the prior art.

According to the second technical means, the first
The average particle size of the recycled powder contained in the layer is 1050μ
Since it is smaller than m, the bending elastic modulus of the molded product can be substantially maintained even when the content of recycled powder in the molded product exceeds 25%.

[0015]

EXAMPLES Examples of the present invention will be described.

FIG. 1 is a sectional view of a sheet molding compound molding (hereinafter referred to as SMC molding) according to this embodiment. The SMC molded product shown in FIG. 1 includes a first SMC layer (first layer) 11 and second SMC layers 12 formed on both surfaces of the first SMC layer 11. First SMC
Layer 11 contains fiber reinforcement 13, thermosetting resin 14, calcium carbonate 15 and recycled powder 16 of SMC waste, and second SMC layer 12 contains fiber reinforcement 1
3, containing thermosetting resin 14 and calcium carbonate 15. Here, the second SMC layer 12 does not contain the recycled powder 16. The calcium carbonate 15 does not have to be contained in the first and second SMC layers 11 and 12.

FIG. 2 is a schematic view of the SMC manufacturing apparatus according to this embodiment, and FIG. 3 is an explanatory view showing a process of obtaining an SMC molded product from two SMCs.

A specific example will be described below.

Example 1 The resin tank 1 of the SMC manufacturing apparatus shown in FIG. 2 was charged with the resin paste A (FIG. 4), and the resin tank 3 was charged with the resin paste C (FIG. 4). Here, the average particle size of the recycled filler (recycled powder of SMC waste) contained in the resin paste A is 22 μm.
m. Resin paste A supplied from resin tank 1
Was coated on the inner surface of the polyethylene film 6 with a doctor knife 5 in an amount of 1080 g per m ² . On the other hand, the resin paste C supplied from the resin tank 3 is applied to the inner surface of the polyethylene film 8 by a doctor knife 5 at 540 m ²
After coating with g, 1 inch of chopped glass strands (glass roving RER4630-SM18 manufactured by Nippon Glass Fiber Co., Ltd.) 9 is sprinkled on 630 g per m ² . Then, the inner surfaces of the two polyethylene films 6 and 8 are overlapped with each other, and the defoamed / impregnated product is wound into a roll and aged at 40 to 50 ° C. for 24 hours, and the polyethylene film 6 side is a recycled filler. 2250 g per m ^{2 of} SMC having the characteristics of the SMC containing the above and the characteristics of the high strength SMC containing no recycled filler on the polyethylene film 8 side were obtained.

Next, this SMC was cut into a size of 270 x 270 mm, and two sheets having the characteristics of SMC containing recycled filler inside were superposed into a 300 x 300 mm flat plate molding die. Then, press molding was carried out under the conditions of a temperature of 140 ° C., a pressing force of 70 tons and a pressing time of 3 minutes to obtain a flat plate molded product having a thickness of 1.9 mm.
At this time, the content rate of recycled filler in the molded product is 2
It was 5% by weight. The front and back outer surfaces of this molded product were completely composed of blue-colored surfaces having the characteristics of high-strength SMC, and no visual defects such as blistering were observed.

Example 2 The same as Example 1 except that the recycled filler contained in the resin paste A had an average particle size of 25 μm, and the description thereof is omitted.

[Example 3] The same as Example 1 except that the average particle diameter of the recycled filler contained in the resin paste A was 400 μm, and the description thereof is omitted.

Example 4 The same as Example 1 except that the average particle size of the recycled filler contained in the resin paste A was 800 μm, and the description thereof is omitted.

Example 5 The same as Example 1 except that the average particle size of the recycled filler contained in the resin paste A was set to 19 μm, and the description thereof is omitted.

[Example 6] The same as Example 1 except that the average particle size of the recycled filler contained in the resin paste A was set to 1050 μm, and the description thereof is omitted.

[Example 7] Resin paste B (Table 1) was charged in the resin tank 1 instead of the resin paste A, and the dispersion amount of the chopped glass strands 9 of 1 inch length was set to 1000 g per m ^2. M ^{2 in the same} manner as in Example 1
An amount of 2500 g of SMC was obtained.

Next, this SMC was cut into a size of 220 × 220 mm and press-molded in the same manner as in Example 1 to obtain a flat plate molded product having a thickness of 2.0 mm. The front and back outer surfaces of this molded product were also completely composed of blue-colored surfaces having the characteristics of high-strength SMC, and no visible defects such as blistering were observed.

FIG. 5 shows the relationship between the recycled filler content and the flexural modulus in the molded products of Examples 1 to 6.
FIG. 6 shows the results of impregnability, appearance, specific gravity, flexural strength and flexural modulus when the recycled filler content in the molded products of Examples 1 to 6 was 25%. However, in FIG. 6, the impregnating property means the mixing property of the recycled filler and the thermosetting resin.

[Conventional Example] Chopped glass strands 9 are dispersed in a thermosetting resin paste containing recycle filler having an average particle diameter of 25 μm and calcium carbonate, and it is an SMC molded article having a single layer structure. FIG. 5 shows the relationship between the recycled filler content and the flexural modulus in the molded product of the conventional example. In addition, the results of the impregnating property, appearance, specific gravity, bending strength and bending elastic modulus when the recycled filler content in the molded product of the conventional example is 20% are shown in FIG.
Shown in.

As is apparent from FIG. 5, the molded products of Examples 1 to 6 had a recycled filler content of 2 in the molded products.
Even if it is increased within the range of not exceeding 5%, the bending elastic modulus can be substantially maintained. It is considered that this is because the recycled filler does not exist near the surface of the molded product, and the proportion of chopped glass strands near the surface increases as compared with the prior art. In addition, the molded products of Examples 1 to 5 show less decrease in flexural modulus than the molded products of Examples 5 and 6 even if the content of recycled filler in the molded products is increased in a range exceeding 25%. . From this, it is considered that the bending elastic modulus in the range where the content of the recycled filler exceeds 25% is closely related to the average particle diameter of the recycled filler, and from the result of FIG. If it is 1050 μm or more, the flexural modulus decreases sharply if the content of recycled filler in the molded product is increased in a range exceeding 25%. Therefore, in the present invention, it is desirable to make the average particle size of the recycled filler smaller than 1050 μm.

Further, as is apparent from FIG.
In the molded product of No. 5, when the recycled filler content is 25%, the flexural strength and the flexural modulus are significantly higher than those of the conventional example. Furthermore, the average particle size of recycled filler is 1
If it is 050 μm or more, it becomes difficult to mix the recycled filler with the thermosetting resin at the time of manufacturing SMC, which makes it difficult to manufacture, and even if a molded product is manufactured, the flexural modulus is greatly reduced and the molded product swells. Poor appearance occurs.

[0032]

The invention of claim 1 has the following effects.

Since the second layer containing no recycled powder is formed on both sides of the first layer containing recycled powder, the recycled powder does not exist near the surface of the molded article, and the fiber reinforced material is present near the surface. Is higher than in the conventional technique, and the bending elastic modulus and bending strength of the molded product are improved. As a result, the flexural modulus and flexural strength of the molded product can be maintained even if the content of recycled powder in the molded product is increased within the range not exceeding 25%. Therefore, more SMC waste can be effectively utilized than in the prior art.

The invention of claim 2 has the following effects.

Since the average particle size of the recycled powder contained in the first layer was made smaller than 1050 μm, the content of recycled powder in the molded product was 2 as apparent from FIG.
Even when it exceeds 5%, the flexural modulus of the molded product can be substantially maintained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sheet molding compound molded product according to the present embodiment.

FIG. 2 is a schematic view of a sheet molding compound manufacturing apparatus according to the present embodiment.

FIG. 3 is an explanatory diagram for manufacturing a sheet molding compound molded product according to the present embodiment from two sheet molding compounds.

FIG. 4 is an explanatory diagram showing a blending component of a resin paste and a blending amount thereof.

FIG. 5 is a graph showing the relationship between the content of recycled filler and the flexural modulus according to the present example and the conventional example.

FIG. 6 is an explanation showing impregnability, appearance of molded product, specific gravity, bending strength, and bending elastic modulus according to the present example (when the recycled filler content is 25%) and the conventional example (when the recycled filler content is 20%). It is a figure.

[Explanation of symbols]

10 SMC molded product (sheet molding compound molded product) 11 1st SMC layer 12 2nd SMC layer 13 Fiber reinforcement 14 Thermosetting resin 16 Recycled powder

Claims (2)

[Claims] 1. A first layer containing a fiber reinforcing material, a thermosetting resin and a recycled powder of a sheet molding compound molded article; and a fiber reinforcing material and a thermosetting resin formed on both surfaces of the first layer. And a second layer containing no recycled powder of the sheet molding compound molded article, and a sheet molding compound molded article. 2. The sheet molding compound molding according to claim 1, wherein the recycled powder contained in the first layer has an average particle size smaller than 1050 μm.