JPH10166466A - Production of glass fiber reinforced polyester resin molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass fiber reinforced polyester resin molded object having high elasticity and excellent outer appearance. SOLUTION: At least two kinds of glass fibers having difference between compression strengths when glass fiber mats are compressed in the thickness direction thereof to be set to 450kg/m<3> in density are used and the mats are selected so that the compression strength of the mat high in compression strength is 1.5-10 times that of the mat low in compression strength and the mat low in compression strength is positioned on the surface layer of a molded object and the mat high in compression strength is positioned on the inner layer of the molded object and these mats are impregnated with an unsaturated polyester resin containing a curing agent and the whole is molded within a mold to obtain a molded object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester resin molded article reinforced with glass fibers, and more particularly to a method for producing a polyester resin molded article having high elasticity and good appearance.

[0002]

2. Description of the Related Art A polyester resin molded article reinforced with glass fiber is generally called an FRP product, and is widely used in various fields such as electric products, automobile parts and housing-related equipment. As one of the methods for manufacturing an FRP product, there is a matched metal die forming method (hereinafter, referred to as an MMD method).

[0003] In the MMD method, a glass fiber mat is placed in a lower mold cavity using a molding mold having an engaging portion around the mold cavity, and a polyester resin compound containing a curing agent is poured from above the mat. This is a method of spraying or flowing down, then closing the mold, heating, and pressurizing to form a molded article according to the mold cavity. M
In the MD method, the mat that has protruded from the mold cavity at the bite portion by closing the mold is cut, and the bite portion is airtight so that resin does not overflow from the mold cavity. Therefore, according to the MMD method, it is possible to obtain a molded article having a good surface gloss and a shape corresponding to the mold cavity.

[0004]

It is desired that the molded article has a high elasticity, that is, a molded article having a small deformation even when a large external force is applied. However, an attempt is made to produce such a high elasticity FRP product by the MMD method. Occasionally, one first tries to increase the amount of reinforcing material, ie glass fiber mat. However,
Increasing the amount of the mat makes it difficult for the polyester resin compound to be evenly dispersed among the fibers, so that the resin does not blend well with the fibers, and it becomes difficult to obtain a high-quality molded product, and a molded product having a wrinkled appearance and poor appearance is obtained. It is more likely to occur, and thus also makes it difficult to obtain a good quality FRP product, and the resulting product is heavy. Therefore, it was necessary to easily obtain a high-quality FRP product having a large elasticity without increasing the weight so much.

The present invention has been made in response to such a need. That is, an object of the present invention is to provide a method capable of easily producing a high-quality FRP product having high elasticity and good appearance.

[0006]

According to the present invention, at least two types of glass fiber mats having a specific relationship in compressive strength are used, and they are arranged at specific positions of an FRP product. The present invention aims to provide an FRP product that satisfies the above-mentioned requirements by incorporating a polyester resin compound into the mixture and molding it by the MMD method.

[0007] When manufacturing FRP products, it is already known to arrange glass fiber mats of various structures in an overlapping manner. For example, JP-A-52-3206
In Japanese Patent Publication No. 2, a glass fiber surface mat is arranged on both sides of a glass fiber swirl mat, and a polyester resin compound, that is, an unsaturated polyester resin containing a curing agent (hereinafter simply referred to as a resin) is contained therein.
The laminated plate is obtained by molding by heating and pressing. However, this publication only teaches the use of mats having different structures in an overlapping manner. As described above, until now, only mats having different structures or manufacturing methods have been used to overlap the mats, and those having different compressive strengths are selected by paying attention to the compressive strength of the mats. Was not used.

The present invention measures the compressive strength when the mat is compressed in the thickness direction, prepares two types of mats having a compressive strength of a certain degree or more, and among them, the compressive strength is small. The main point is that a mat is arranged on the surface layer, a mat having a high compressive strength is arranged on the inner layer, the mats are overlapped, and a resin is included in the mat to form an FRP product.

According to the present invention, a plurality of glass fiber mats are stacked in a mold cavity of a molding die, a resin is contained in the mat, the mold is closed, and the mat and the resin are filled in the mold cavity. In a method of manufacturing a FRP molded body by curing a resin,
Compressed in the thickness direction as a mat to increase the density to 450 kg / m
^At least two types of glass fiber mats are used in which the compressive strength is 1.5 times or more and 10 times or less than the small one in the compressive strength when set to ^3. Further, the present invention provides a method for producing an FRP molded body, wherein a mat having a large compressive strength is placed in a mold cavity so that the mat is located in an inner layer of the molded body.

[0010] The invention is based on the compressive strength when set to 450 kg / m ³ density to compress the mat in the thickness direction. The method of determining the compression strength is based on JIS K7220, which defines a compression test method for hard foamed plastic.
It imitates. Specifically, six mats each having a thickness of 3 mm, a width and a length of 100 mm are stacked to a thickness of 18 mm,
A load is applied to this, and the compressive strength is calculated from the value of the compressive load when the density becomes 450 kg / m ³ .

In this case, how to determine the thickness of the mat becomes a problem, which is determined as follows. First, six 300 mm square mats are stacked on a flat plate, and then a 600 g glass plate (300 mm
Corner), the thickness of six mats is measured, the thickness of one mat is calculated from the value, and this is defined as the thickness of the mat.

As mats having different compressive strengths, mats resulting from differences in strands constituting the mat can be used. For example, chopped strand mats, continuous strand mats, filament mats, and composite types thereof are mats having different compressive strengths. In the present invention, a mat having a high compressive strength and a mat having a small compressive strength are measured from the mats having different configurations to measure the compressive strength,
Moreover, the compression strength of the larger one is smaller than that of the smaller one.
At least two kinds in a range of 5 to 10 times are used in combination. 1.5 times to 10 above
Within the range of 2 times, it is preferable to combine 2 times to 8 times, and most preferably, 3 times to 5 times.

The compressive strength of the mat can be different even when glass fiber filaments having the same thickness and length are used, only by changing the amount of the binder when forming the mat. For example, 80 attached to the bottom of a glass melting furnace
A glass fiber filament is spun from a 0-hole nozzle, and a polyvinyl acetate-based sizing agent is applied immediately thereafter.
The wound glass fiber is dried at 130 ° C. for 8 hours to make a cake. Strands are drawn out of the 200 cakes and cut into 2 inch lengths by a cutter to obtain chopped strands. This chopped strand is deposited on a mesh-shaped conveyor, and a binder of 12, 7, 4 and 2.5% by weight is applied thereto and dried, and a chopped strand having a unit weight of 450 g / m ² and a thickness of 3 mm is provided. Mats A, B, C and D were obtained. These mats A, B, C and D have a density of 450
The compressive strength at the time of kg / m ³ is 1.0, 0.
3, 0.1 and 0.02 kg / cm ² . The mats A, B, C and D are all examples of mats that can be used in the present invention.

According to the present invention, the mat is arranged in the mold cavity so that the mat having a low compressive strength comes to the surface layer of the molded body and the mat having the high compressive strength comes to the inner layer of the molded body. Put the mats on top of each other. That is,
Assuming that the compressive strength of the mat coming to the inner layer is x and the compressive strength of the mat coming to the surface layer is y, the value of x to y (this is called the compressive strength ratio) is in the range of 1.5 to 10. At this time, the mat having a high compressive strength and the mat having a low compressive strength may be respectively provided as a single layer. However, it is preferable that a mat having a high compressive strength is laminated in plural layers, and a mat having a low compressive strength is laminated in plural layers. It is to arrange the object so that it comes to the surface layer and the inner layer.

According to the present invention, after the mat is placed in the mold cavity, the FRP product is manufactured by operating in exactly the same manner as in the conventional method. That is, after the resin is sprayed or dropped on the mat thus placed, the mold is closed and pressurized, the mat and the resin are filled in the mold cavity, and the resin is cured by heating. Cool and open the mold, FR
Take out the P product.

[0016]

According to the present invention, at least two kinds of mats having a high compressive strength and a low compressive strength are prepared as mats, and a mat having a high compressive strength has a strength 1.5 to 10 times that of a small one. Select and use them, and place them in the mold cavity so that the mat with low compressive strength comes to the surface layer of the molded body and the mat with high compressive strength comes to the inner layer, and then superimpose, then add the resin Then, the obtained molded body has a good appearance, and has a high elasticity for its weight and is hardly deformed by an external force. Although the cause is not clear, mats with low compressive strength are arranged on the surface layer (both upper and lower surface layers), and mats with high compressive strength are arranged on the inner layer. Mats (mats with low compressive strength) will be compressed more than mats in the inner layer (mats with high compressive strength). It is also presumed that the surface layer (both the upper and lower surface layers) has a higher fiber content than the inner layer, resulting in high elasticity.

The advantages of the present invention will be specifically described below with reference to examples and comparative examples. Here, the mats A, B, C, and D described above and each having a size of 1.2 m in length and 1.2 m in width are used.

[0018]

Embodiment 1 In this embodiment, the mat A described above is used.
And a mat B, a compact was produced by the MMD method. As the resin, a polyester resin compound having the following composition was used. Unsaturated polyester resin 100 parts by weight Methyl ethyl ketone peroxide (curing agent) 1 part by weight Calcium carbonate 30 parts by weight

The molding die is a die for molding a unit panel for assembling a water tank.
One having a mold cavity for molding a shallow box having a size of m, 1 m in width and 7 cm in height was used.

In this embodiment, three mats B are stacked as the lower surface layer, three mats A are stacked as the inner layer, and three mats B are stacked as the upper surface layer, and these mats are stacked in the mold cavity. Placed. In this case, the mat A having a high compressive strength has a compressive strength of 1.0 kg / cm ² when compressed to a density of 450 kg / m ³ , and the mat B has a compressive strength of 0.3 kg / cm ³ when similarly compressed. ^Since it was ² , the mat A having the higher compressive strength had 3.3 times the compressive strength of the mat B having the lower compressive strength. Therefore, the ratio of the inner layer to the surface layer, that is, the compressive strength ratio was 3. It was 3. 14 kg of the resin was poured onto the mats arranged in this manner, the mold was closed, and the resin was cured at 60 ° C. for 20 minutes to obtain an FRP panel.

Using this panel, JIS K6119
The flexural strength and flexural modulus were measured according to the method specified in, and a panel was attached to the upper surface of a steel box-shaped surface pressure test vessel equipped with a pressure gauge, and water pressure was applied to the inside of the vessel, causing the panel to break. The pressure at that time was measured, and this was defined as the surface pressure strength. This panel has a good appearance and a bending strength of 21.5k
g / mm ² , the flexural modulus was 897 kg / mm ² , and the surface pressure strength was 1.2 kg / cm ² .

[0022]

Embodiment 2 This embodiment was carried out in exactly the same manner as in Embodiment 1 except that the mat used was changed. Mats A and C are used as mats. Three mats C are stacked on the upper surface layer, three mats A are stacked on the inner layer, and three mats C are stacked on the lower surface layer. They were placed one above the other in the fossa. In this case, the mat A has a density of 4
Compressive strength when compressed to 50 kg / m ³ is 1.0 kg / m ³
cm ² , and the compressive strength of the mat C is 0.1 kg / cm ² when compressed in the same manner, so that the compressive strength ratio is 10.

The obtained panel has a good appearance, a bending strength of 21.9 kg / mm ² and a flexural modulus of 913 kg / m.
m ² , the surface pressure strength was 1.2 kg / cm ^{2, and} it was of high elasticity and good quality.

[0024]

Embodiment 3 This embodiment was carried out in the same manner as in Embodiment 1, except that only the mat was changed. The mats B and C are used as mats. Three mats C are stacked on the upper surface layer, three mats B are stacked on the inner layer, and three mats C are stacked on the lower surface layer. These were placed one on top of the other. In this case, the mat B has a density of 450 kg.
/ M ³ has a compressive strength of 0.3 kg / cm ² , and the mat C has a compressive strength of 0.1 kg when similarly compressed.
Since it is kg / cm ² , the compressive strength ratio is 3.

The resulting panel has a good appearance, a bending strength of 20.3 kg / mm ² and a flexural modulus of 985 kg / m.
m ² , the surface pressure strength was 1.2 kg / cm ^{2, and} it was of high elasticity and good quality.

[0026]

Embodiment 4 This embodiment was carried out in the same manner as in Embodiment 1, except that only the mat used was changed. As the mat, a mat C and a mat D are used, and three mats D are stacked on the upper surface layer, three mats C are stacked on the inner layer, and three mats D are stacked on the lower surface layer, and these mats are used. They were placed one on top of the other in the mold cavity. In this case, the mat C has a density of 45.
Compressive strength when compressed in 0 kg / m ³ is 0.1 kg / c
m ^2, and since the mat D compressive strength when compressed in the density of 0.02 kg / cm ^2, compression strength ratio 5.
0.

The resulting panel has a good appearance, a bending strength of 20.4 kg / mm ² and a flexural modulus of 996 kg / m.
m ² , the surface pressure strength was 1.2 kg / cm ^{2, and} it was of high elasticity and good quality.

[0028]

Embodiment 5 This embodiment was carried out in the same manner as in Embodiment 1, except that only the mat used was changed. Mats B and C are used as mats. Two mats C are stacked on the upper surface layer, five mats B are stacked on the inner layer, and two mats C are stacked on the lower surface layer. They were placed one above the other in the fossa. The compression strength ratio is 3.

The obtained panel has a good appearance, a bending strength of 22.5 kg / mm ² and a flexural modulus of 1034 k.
g / mm ² , the surface pressure strength is 1.2 kg / cm ² ,
High elasticity and good quality.

[0030]

Embodiment 6 This embodiment was carried out in the same manner as in Embodiment 1, except that only the mat used was changed. Mats C and B are used as mats. Four mats C are stacked on the upper surface layer, only one mat B is used on the inner layer, and four mats C are stacked on the lower surface layer. These mats are used. They were placed one on top of the other in the mold cavity. The compression strength ratio is 3.0.

The obtained panel had a good appearance, a bending strength of 15.7 kg / mm ² and a flexural modulus of 765 kg.
/ Mm ² , the surface pressure strength was 0.9 kg / cm ² , and the high elasticity was good.

[0032]

Comparative Example 1 This comparative example was performed in the same manner as in Example 1, except that only the mat used was changed. The same mat B is used for both the surface layer and the inner layer, and three mats B are stacked on the upper surface layer, three mats B are stacked on the inner layer, and three mats B are stacked on the lower surface layer. It was arranged inside. The compression strength ratio is 1.

Although the obtained panel had a good appearance,
The flexural strength was low at 13.6 kg / mm ² , and the flexural modulus was good at 765 kg / mm ² , but the surface pressure strength was a little low at 1.0 kg / cm ^2, and thus the whole was good. Was not.

[0034]

Comparative Example 2 This comparative example was performed in the same manner as in Example 1, except that only the mat used was changed. Mat A and mat B were used as mats, and mat A
Were stacked, three mats B were stacked on the inner layer, three mats A were stacked on the lower surface layer, and these mats were arranged in the mold cavity. The compression strength ratio is 0.3.

The obtained panel had good appearance, but had a bending strength of 11.2 kg / mm ² , a flexural modulus of 690 kg / mm ² and a surface pressure strength of 0.8 kg / cm ^2.
However, all were low and therefore not good.

[0036]

Comparative Example 3 This comparative example was performed in the same manner as in Example 1, except that only the mat used was changed. Mat B and mat C are used as mats, and mat B
, Three mats C were stacked on the inner layer, and three mats B were stacked on the lower surface layer, and these mats were arranged in the mold cavity. The compression strength ratio is 0.33.

The obtained panel had a good appearance,
Flexural strength 10.7 kg / mm ² , flexural modulus 657
kg / mm ² , and the surface pressure strength was 0.8 kg / cm ² , all of which were low and therefore not good.

[0038]

Comparative Example 4 This comparative example was performed in the same manner as in Example 1, except that the mat used was changed. Mat B and mat C are used as mats, and mat B
And three mats were used in the inner layer, and four mats B were used in the lower surface layer. These mats were arranged in the mold cavity. The compression strength ratio is 0.33.

Although the obtained panel had a good appearance,
Flexural strength 8.8 kg / mm ² , flexural modulus 623k
g / mm ² , and the surface pressure strength was 0.7 kg / cm ² .

[0040]

Comparative Example 5 This comparative example was carried out in the same manner as in Example 1, except that the mat used was changed. Mat B and mat C are used as mats, and mat B
Were stacked, five mats C were stacked on the inner layer, and two mats B were stacked on the lower surface layer, and these mats were arranged in the mold cavity. The compression strength ratio is 0.33.

The resulting panel had a slightly good appearance, but had a flexural strength of 11.0 kg / mm ² and a flexural modulus of 6.
Both were low at 78 kg / mm ² and the surface pressure strength was 0.8 kg / cm ² , and were not good.

[0042]

Comparative Example 6 This comparative example was carried out in the same manner as in Example 1, except that the mat used was changed. Mat B and mat D are used as mats, and mat D
Were used, three mats B were stacked on the inner layer, and three mats D were stacked on the lower surface layer. These mats were arranged in the mold cavity. The compression strength ratio is 15.

The obtained panel had a bending strength of 18.9 k.
g / mm ² , the flexural modulus was 794 kg / mm ² , and the surface pressure strength was 1.1 kg / cm ² , all of which were good. However, since the appearance was poor, the whole was poor.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // B29K 33:04 B29C 67/14 U 105: 08 309: 08 (72) Inventor Akira Miyo 6 Kinuigaoka, Moka-shi, Tochigi Pref. Address Fujioka Bargrass Co., Ltd. Moka Plant (72) Inventor Koji Ukigaya 6th Kinuigaoka, Moka City, Tochigi Prefecture Fujifi Bargrass Co., Ltd. 6 Kaigaoka Inside the Fujioka Bargrass Moka Plant

Claims (1)

[Claims] 1. A plurality of glass fiber mats are laid one on top of another in a mold cavity of a molding die, an unsaturated polyester resin containing a curing agent is added to the mat, the mold is closed, and the mat and the resin are molded. In a method of manufacturing a molded article by filling the inside and curing the resin, the mat is compressed in the thickness direction to have a density of 4%.
At least two types of glass fiber mats, in which the compression strength at 50 kg / m ³ is 1.5 times or more and 10 times or less as large as the small one, are used. A method for producing a polyester resin molded article reinforced with glass fibers, wherein the mat is placed in a mold cavity so that a mat having a high compressive strength is located on an inner layer of the molded article, which is located on a surface layer.