JPS6343A - Box body made of plastic and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is applicable to plastic casings that require airtightness, flame retardancy, and strength, such as vacuum or pressure-resistant containers, and plastic casings such as equipment housings. It concerns the body and its manufacturing method.

[Conventional technology]

Plastic casings are used in various fields, and recently, plastic casings reinforced with reinforcing fibers such as glass fibers have been used in various fields. This type of plastic Wffi body is made by subjecting a molding material using short glass fibers or long glass fibers to injection molding or stamping molding. In the case of injection molding, short glass fibers are mixed with a thermoplastic resin such as polypropylene or polyethylene, other additives are added, and the mixture is put into an injection molding machine. In addition, in the case of stamping molding, long glass fibers are impregnated with a thermoplastic resin such as polypropylene, other additives are added, and this is formed into a sheet to create a glass fiber reinforced thermoplastic resin sheet. This is then molded using a stamping press.

In addition to the method of manufacturing a plastic casing using a molding material using thermoplastic resin as described above, a molding material (sheet molding compound, SM
There is also a manufacturing method using C).

[Problem that the invention seeks to solve]

However, each of the above three types of manufacturing methods has the following drawbacks, and the reality is that a satisfactory plastic casing has not yet been obtained.

In other words, in the injection molding method using short glass fiber reinforced molding materials, the glass fibers that serve as reinforcing fibers are short fibers, which weakens the strength of the resulting plastic casing, and at the same time poses problems with dimensional stability. It has the disadvantage that molded products cannot be manufactured.

In the method of stamping molding material using long glass fibers, the glass fibers that serve as reinforcing fibers are long fibers,
Some of the long fibers extend from the surface of the casing to the inside, and air flow paths are likely to be formed along this path, making it difficult to manufacture casings with excellent airtightness. have.

In particular, when using a non-halogen type flame retardant such as aluminum hydroxide, this M flame retardant has a negative effect on the adhesion between the reinforcing glass fiber and the resin.
Air flow paths are more likely to be formed along the long glass fibers, and the airtightness of the plastic housing is significantly impaired. If a flame retardant is used in this way, the airtightness will be significantly impaired, so there is a limit to the amount of flame retardant used, and therefore there is a limit to the improvement in flame retardancy.

In addition, the method of manufacturing plastic casings using SMC has disadvantages in that the molding cycle becomes longer and costs increase, and the resulting product has poor weather resistance and is heavier. ing.

As described above, all of the conventional methods have problems, and improvement thereof is strongly desired.

The present invention was made in view of the above circumstances, and provides a lightweight and inexpensive plastic casing that has excellent mechanical strength and dimensional stability, is airtight, flame retardant, weather resistant, and a method for manufacturing the same. The purpose is to provide.

[Means for solving the invention]

In order to achieve the above object, the present invention comprises a compression molded resin composite material having a short fiber reinforced thermoplastic resin layer and a long fiber reinforced thermoplastic resin layer. The first aspect is the plastic casing in which the inner portion is formed, and the short fiber-containing thermoplastic resin sheet-like molding material and the long fiber-containing thermoplastic resin sheet-like molding material are made to have a quasi-θm.

After preheating at least long fiber-containing thermoplastic resin sheet-like molding materials among these sheet-like molding materials,
'A?' is a plastic housing made by laminating both sheet molding materials and compression molding them in that state. Let 'h be the second gist.

That is, in order to achieve the above object, the present inventors
- As a result of repeated research, we created two types of molding materials using thermoplastic resin as the matrix resin, one containing short fibers and one containing long fibers, and when these were laminated and compression molded, It is hoped that the advantages of short fiber-reinforced and long fiber-reinforced materials will be utilized and the disadvantages will be canceled out, thereby making it possible to obtain an ideal plastic casing. This discovery led to the present invention.

The plastic casing of the present invention is obtained using a short fiber-reinforced thermoplastic resin molding material and a long fiber-reinforced thermoplastic resin molding material.

Examples of the short fibers in the short fiber-reinforced thermoplastic resin molding material include short glass fibers, short whisker fibers, short carbon fibers, and the like. However, short glass fibers are usually used. This short glass fiber is made by gathering about 20 to 100 glass filaments into a strand.
Chopped strands are used by cutting this into appropriate lengths. Usually, the short fibers used have a length of 0.5 to 2.0 cm.

Examples of the thermoplastic resin used in the short fiber-reinforced thermoplastic resin molding material include polypropylene, polycarbonate, and polyethylene. Usually polypropylene or polyethylene is used.

The long fibers of the long fiber-reinforced thermoplastic resin molding material are the same type as the short fibers used in the short fiber-reinforced thermoplastic resin molding material.1. It is used by setting its length to be longer than short fibers. Usually, the above-mentioned long fibers include 1
A length of 00 to 300n is used. Like the short fibers mentioned above, these long fibers are usually made of glass long fibers,
- Roving is generally used.

In addition, conventionally known flame retardants such as magnesium hydroxide and aluminum hydroxide, and additives such as antioxidant 2 and color inhibitor are appropriately used in the above-mentioned molding material.

The plastic casing of the present invention can be produced by subjecting the short fiber-reinforced thermoplastic resin molding material and the long fiber-reinforced thermoplastic resin molding material to a compression molding machine. In this case, the above-mentioned molding material is usually formed into a so-called stampable sheet by a conventionally known method, and then,
They are laminated, and in that state, they are compression molded using a compression molding machine to produce a product. However, with regard to long fiber reinforced thermoplastic resin molding materials, there may be a situation where the resin does not flow smoothly during the above compression molding. It is preferable to overlap and compression mold a fiber-reinforced thermoplastic resin molding material.

Note that the above preheating is preferably performed not only for the long fiber-reinforced thermoplastic resin molding material but also for the short fiber-reinforced thermoplastic resin molding material. In addition, during the above compression molding, the short fiber-reinforced thermoplastic resin molding material is set to constitute the inner part (inner wall surface) of the plastic casing, and the long fiber-reinforced thermoplastic resin molding material is set to constitute the opposite side. There is a need to.

By doing so, it is made of a compression molded composite material with a short fiber reinforced thermoplastic resin layer and a long fiber reinforced thermoplastic resin layer, and the inner part is made of a plastic material made of a short fiber reinforced thermoplastic resin layer. You will now be able to obtain a casing.

The plastic casing obtained above has an inner portion made of a short fiber-reinforced thermoplastic resin layer and an opposite side made of a long fiber-reinforced thermoplastic resin layer.
It has excellent mechanical strength and dimensional stability, and is rich in airtightness, flammability, and weather resistance, and is lightweight and inexpensive. In other words, the plastic casing has high mechanical strength because it is composed of not only short fiber-reinforced thermoplastic resin but also a composite resin with long fiber-reinforced thermoplastic resin, which has high mechanical strength and dimensional stability. , and has good dimensional stability. Therefore, it is also possible to increase the size. Furthermore, since the inner part is composed of a short fiber-reinforced thermoplastic resin layer, it is highly airtight. In other words, since the reinforcing fibers in the short fiber-reinforced thermoplastic resin layer are short, the fibers extend from the front surface to the back surface of the resin layer as in the case of using long fibers, and air flow paths are formed along the long fibers. This is because there will be no such situation.

What's more, this Blastiuk housing is also very W1m friendly. − Generally, when it is necessary to increase flame retardancy,
It is necessary to use a large amount of a flame retardant such as aluminum hydroxide to form air passages by impairing the wettability of the resin and fibers, but in this case, the airtightness of the casing is likely to be impaired. However, the plastic casing of the present invention can achieve a high degree of flame retardancy while maintaining airtightness by incorporating a large amount of the flame retardant into the short fiber-reinforced thermoplastic resin layer that is the inner layer. can. That is, in the short fiber reinforced thermoplastic resin layer, since the reinforcing fibers are short, the fibers do not extend from the front surface to the back surface of the resin layer. Since the air passages formed along the fibers do not form, airtightness is not impaired at all even if a large amount of the flame retardant material, which reduces the wettability of the reinforcing fibers and the resin, is used. In this case, the flame retardant should not only be blended in a large amount in the short fiber-reinforced thermoplastic resin layer of the inner layer (it is also possible to blend a large amount in the outer long fiber-reinforced thermoplastic resin layer). By doing so, a sufficient flame retardant effect can be obtained even if the outer layer is directly exposed to flame.

As described above, the present invention achieves high flame retardancy while maintaining airtightness, and also achieves a significant improvement in mechanical strength and dimensional stability by combining with long fiber reinforced thermoplastic resin. Yes, this is its biggest feature. In addition, since the outer layer of the plastic casing of the present invention is made of a resin layer reinforced with long fibers, there is very little resin dripping due to heat softening even when exposed to flame, and therefore it does not spread to other parts. This prevents the fire from spreading.

〔Effect of the invention〕

Since the plastic casing of the present invention is constructed as described above, the advantages of the short fiber reinforced thermoplastic resin and the long fiber reinforced thermoplastic resin are taken advantage of, the disadvantages are negated, and the mechanical strength is 2 dimensional. Highly stable, airtight and flame retardant. Furthermore, since the resin used is a thermoplastic resin, it has excellent weather resistance, is lightweight, and is inexpensive. Further, according to the manufacturing method of the present invention, the plastic casing described above can be manufactured in a stable state at all times. In other words, it is difficult for long fiber-containing thermoplastic resin sheet materials to smoothly cast the resin during compression molding, but by preheating the long fiber-containing thermoplastic resin sheet materials in advance, it is possible to This improves the flowability and allows the plastic casing to be finished in a stable state every time.

Next, examples will be described.

〔Example〕

First, a short glass fiber reinforced thermoplastic resin sheet molding material and a long glass fiber reinforced thermoplastic resin sheet molding material were manufactured by a conventionally known method according to the raw material compositions shown in Table 1.

Next, using the above two types of sheet-like molding materials, a cylindrical case main body and a disc-like lid were respectively produced by compression molding the above-mentioned box molding materials in a laminated state using a compression molding machine. . In this case, the inner portions of both the casing body and the lid body were configured to be composed of short glass fiber-reinforced thermoplastic resin sheet-like molding material. Then, the housing zero body 1 shown in FIG.
and cover body 2, and then bolt 4 through O-ring 3.
and tightened with nuts 5 to form a sealed casing (pressure vessel). In FIG. 1, 6 is a short glass fiber reinforced thermoplastic resin layer, and 7 is a long glass fiber reinforced thermoplastic resin layer. Next, a water pressure of IQ kg/cal was applied to the obtained sealed casing, and after leaving it for day and night, we examined the state of water intrusion into the interior. A flame retardancy test was conducted by exposing the sealed casing to the flame of a gas burner, and the results showed good results.

Note that the sealed casing shown in Figure 1 uses a composite of two types of molded feed, a short fiber-reinforced thermoplastic resin sheet molding material and a long fiber-reinforced thermoplastic resin sheet molding material. As shown in FIG. 3, a composite material having a structure in which a long fiber-reinforced thermoplastic resin layer 7 is sandwiched between short fiber-reinforced thermoplastic resin layers 6 above and below may be used, or as shown in FIG. A composite material having a structure in which reinforced thermoplastic resin layers 6 and long fiber reinforced thermoplastic resin layers 7 are alternately laminated to a total of four layers may be used. Further, a composite material having a multi-layered structure may also be used. Even when using such a multilayered composite material,
As long as the inner part of the casing is made of short fiber reinforced thermoplastic resin molding material, excellent effects can be obtained as in the previous embodiment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention, and FIGS. 2 and 3 are explanatory views of modified examples of the composite material used therein. ■... Housing body 2... Lid body 6... Short glass fiber reinforced thermoplastic resin layer 7... Long glass fiber reinforced thermoplastic resin layer Patent applicant Sumitomo Electric Industries, Ltd. Figure 1 Figure 2 Map 3

Claims (6)

[Claims] (1) It is composed of a compression molded resin composite material comprising a short fiber reinforced thermoplastic resin layer and a long fiber reinforced thermoplastic resin layer, and the inner part of the casing is formed of the short fiber reinforced thermoplastic resin layer. A plastic casing featuring (2) The short fibers of the short fiber reinforced thermoplastic resin layer have a fiber length of 0.
．． The plastic casing according to claim 1, which is made of short glass fibers of 5 to 2.0 mm. (3) The long fibers of the long fiber reinforced thermoplastic resin layer have a fiber length of 1
The plastic casing according to claim 1, which is made of long glass fibers of 00 to 300 mm. (4) Prepare a short fiber-containing thermoplastic resin sheet molding material and a long fiber-containing thermoplastic resin sheet molding material, and at least the long fiber-containing thermoplastic resin sheet molding material of these sheet molding materials. A method for manufacturing a plastic casing, which is characterized by preheating, laminating both sheet-like molding materials, and compression-molding them in that state. (5) The short fibers of the short fiber reinforced thermoplastic resin layer have a fiber length of 0.
．． 5. The method for manufacturing a plastic casing according to claim 4, wherein the short glass fibers are 5 to 2.0 mm. (6) The long fibers of the long fiber reinforced thermoplastic resin layer have a fiber length of 1
5. The method for manufacturing a plastic casing according to claim 4, wherein the plastic casing is made of long glass fibers having a length of 00 to 300 mm.