JP2001171010A - Part of long glass fiber-reinforced polypropylene resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a part of a long glass fiber-reinforced polypropylene resin which is compatible with contradictory requirements for improving strength and impact resistance to be applicable to wide purposes. SOLUTION: Pellets for dilution of a propylene homopolymer resin are added to base pellet in which glass fibers are impregnated with a propylene block copolymer resin, and the mixed pellets are injection-molded to form the step of a vehicle. Since the block copolymer adheres strongly to the glass fibers as compared with the homopolymer, the impact resistance, which is characteristic of the block copolymer, can be demonstrated effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long glass fiber reinforced polypropylene resin component formed from a glass fiber reinforced polypropylene resin.

[0002]

[Related Background Art] This kind of polypropylene resin has been widely used for various industrial parts because of its excellent mechanical strength, heat resistance, moldability, etc., for example, as a step for getting on and off a truck or a large passenger car. There is a case where a stampable sheet in which a polypropylene resin is reinforced with glass fibers is applied. As is well known, a stampable sheet is formed by pressing a homopolypropylene resin pellet impregnated with long glass fibers and pressing the same, but it is originally sufficient in terms of aesthetics without obtaining good surface properties. I couldn't say. In addition, in order to form a slender-shaped step for getting on and off having a large number of through holes, in order to avoid shearing of the long glass fiber at the time of press molding, a state is left in which a thin skin immediately before penetrating each through hole, After that, since the thin skin is cut, the end of the glass fiber is exposed from the cut surface, and there is a problem that the appearance is further impaired. In addition, the step for getting on and off may be subjected to rough handling such as dropping attached snow and mud with a scoop or the like.However, homo-polypropylene resin deteriorates impact resistance especially at low temperature, so It was not suitable for such use.

On the other hand, separately from the above-mentioned stampable sheet, for example, as described in Japanese Patent Application Laid-Open No. 9-207233, the sheet is manufactured by injection molding having excellent surface properties in order to improve aesthetic appearance. There is also a step for getting on and off in which a homo-polypropylene resin is mixed with a block-type polypropylene resin having excellent impact resistance in order to improve the property. In this step of getting on and off, a homo-polypropylene resin impregnated with glass fiber and a base pellet impregnated with a dilution pellet made of only a block-type polypropylene resin at a predetermined blend ratio are used as raw materials. I have.

[0004]

In the glass long fiber reinforced polypropylene resin used in the step for getting on and off the above-mentioned publication, the block type polypropylene resin which contributes to the improvement of impact resistance and the glass fiber do not adhere sufficiently. As a result, satisfactory impact resistance was not obtained as a result. Therefore, this polypropylene resin cannot be used for parts requiring high impact resistance, and there has been a demand for a long glass fiber reinforced polypropylene resin part which can be applied to a wider use.

An object of the present invention is to provide a long glass fiber reinforced polypropylene resin part which can satisfy both conflicting demands for improvement in strength and impact resistance, and can be applied to a wide range of uses.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a copolymer of ethylene and propylene is arranged as an island layer in a sea layer of polypropylene and reinforced with glass fibers. It was formed by adding a polypropylene formed by polymerizing propylene alone to a glass long fiber reinforced polypropylene block. Therefore, at the time when the polypropylene of the propylene simple substance is added to the polypropylene block, since the glass fibers are already firmly adhered to the polypropylene block, the impact resistance characteristic of the polypropylene block is effectively exhibited. .

According to the invention of claim 2, a copolymer of ethylene and propylene is disposed as an island layer in a sea layer of polypropylene, and a polypropylene continuous glass fiber reinforced block reinforced with glass fibers is provided with propylene alone. Was added to polypropylene, and injection molded into a vehicle step mold. Therefore, a good appearance can be obtained by manufacturing by injection molding with excellent surface properties, and at the time when the propylene simple substance polypropylene is added to the polypropylene block, the glass fibers are already firmly adhered to the polypropylene block. Therefore, the impact resistance characteristic of the polypropylene block body is effectively exhibited.

Further, in the invention of claims 1 and 2, it is preferable to set the ratio of the long glass fiber reinforced polypropylene block to the polypropylene of propylene alone to a large ratio of the polypropylene block. In this case, since the content of the polypropylene block increases, higher impact resistance can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in steps for getting on and off a vehicle will be described below. The step for getting on and off according to the present embodiment is applied to a vehicle having a cabin (cabin) provided at a relatively high position, such as a truck or a large passenger car, and is attached to a position below a door on the outside of the vehicle body so as to be attached to the cabin. Used when getting on and off. As shown in the perspective view of FIG. 1, the step surface 2 of the step for getting on and off 1 is in the shape of a saw having a large number of through holes 2 a penetrating vertically, and a garnish portion 3 is integrally formed so as to surround the step surface 2. Is formed. The garnish portion 3 is used for mounting the step 1 for getting on and off, and the garnish portion 3 is fixed to an outer surface of the vehicle body by a bolt (not shown).

[0010] In the vehicle equipped with the step 1 for getting on and off constructed as described above, the labor for getting on and off can be achieved by temporarily putting the foot on the step surface 2 when getting on and off the cabin. Since the entire weight is applied to the step surface 2 at this time, the getting-on / off step 1 is required to have sufficient strength, and is subjected to rough handling such as dropping mud or snow attached to the step surface 2 with a scoop. Because of the possibility, the step 1 for getting on and off must have sufficient impact resistance. In order to satisfy the above requirements, in this embodiment, the step 1 for getting on and off is integrally injection-molded with long fiber reinforced polypropylene, and a mixture of a homo resin and a block resin is used as the polypropylene resin. And
As described below, the blend ratio and base resin are selected.

As is well known, a block type polypropylene resin is a homopolymer of propylene, whereas a block type polypropylene resin is obtained by arranging a copolymer of ethylene and propylene as an island layer in a sea layer of polypropylene. Become. When the homo-type and the block-type are compared, as shown in FIG. 2, the homo-polypropylene resin (indicated by □ in the figure) shows that the amount of displacement when a load is applied is the block-type polypropylene resin (indicated by x in the figure). ), It is excellent in strength (rigidity) because it is less, whereas, as shown in FIG. 3, the block-type polypropylene resin can withstand higher breaking energy than the homo-type polypropylene resin, so that it has high impact resistance. Excellent in terms of surface.

In order to injection-mold a homo-based polypropylene resin and a block-based polypropylene resin at an appropriate blend ratio in order to achieve both strength and impact resistance, one of the resins is impregnated with glass fiber. Pellets (hereinafter, referred to as base pellets) are added to the base pellets, and pellets composed of only the other resin (hereinafter, referred to as dilution pellets) are used as raw materials. In addition, the base pellet is manufactured by impregnating the resin while continuously drawing the glass fiber bundle in the polypropylene resin, and cutting the fiber at a predetermined length in the fiber direction. The surface treatment with a coupling agent ensures the adhesion between the polypropylene resin and the glass fiber. As the base pellets,
For example, products in which the content of glass fibers is changed every 10% by weight are prepared as products.

In this embodiment, a block-type polypropylene resin is used as the base pellet and a homo-type polypropylene resin is used as the dilution pellet, contrary to the step for getting on and off described in JP-A-9-207233. are doing. In other words, a pellet for diluting consisting only of a homo-based resin is added to a pellet for a base obtained by impregnating glass fibers into a block-based resin to form a raw material. Here, it has been found that the adhesion to the glass fiber is largely contributed by the polypropylene resin used as the base pellet, and the dilution pellet hardly affects the adhesion. In other words, the block polypropylene resin adheres strongly to the glass fiber at the stage of manufacturing the base pellet, so that the impact resistance of the block polypropylene resin is effectively exhibited even in a later molded product. Become.

Therefore, the physical properties of the molded product obtained when the block-type polypropylene resin is used as a base will be described by taking blend ratios of 2: 1 and 4: 5 (weight ratio of pellets for base: pellets for dilution) as examples. Verify. As shown in Table 1 below, when it is desired to set the content of the glass fiber (GF) in the final step 1 for getting on and off to be, for example, 40% by weight, 50% by weight of base pellets at a blend ratio of 2: 1 It can be seen that at a blend ratio of 4: 5, a base pellet of 60% by weight should be used. Then, the pellets for dilution are added to the pellets for base according to these conditions, heated and melted, and injection-molded into a mold by an injection molding machine, and the step 1 for getting on and off the desired glass fiber content and blend ratio is performed. Obtainable.

[0015]

[Table 1]

In FIGS. 2 and 3, in addition to the physical properties of the block-based resin and the homo-based resin alone, a blend ratio of 2: 1 based on the block-based polypropylene resin is shown. 2 shows the physical properties when a blend ratio of 2: 1 was achieved based on the base resin. As shown in FIG. 2, when the block resin was used as the base (indicated by a circle in FIG. 2), the homo-resin was used. Although the strength is slightly reduced as compared with the case of using the base (indicated by the symbol in the figure), the impact resistance is much higher as shown in FIG. It can be seen that impact resistance can be obtained. The reason that the impact resistance is greatly improved when the block resin is used as the base is not only because the content of the block resin advantageous to the impact resistance is increased under the blend ratio of 2: 1 but also because This is because the block-type polypropylene resin is firmly adhered to the glass fiber as described above, and the characteristic impact resistance is effectively exhibited.

As described above, in the step of getting on and off the vehicle of the present embodiment, not only a good aesthetic appearance can be obtained by manufacturing by injection molding having excellent surface properties, but also a block type polypropylene resin is firmly applied to the glass fiber. Adhesion makes it possible to dramatically improve impact resistance with almost no reduction in strength compared to those based on homo-polypropylene resin described in the gazette, thereby improving strength and impact resistance Can be satisfied together.

Further, when a block resin is used as a base as in the present embodiment, setting the blend ratio in which the ratio of the base pellet side is increased as described above results in a lower content of the block resin. Because of the increase, higher impact resistance can be obtained. Therefore, for example, in Table 1, the step of getting on and off can be manufactured with the blend ratio of 2: 1 which is more excellent in the impact resistance than the blend ratio of 4: 5.

Furthermore, in this embodiment, since the long glass fiber reinforced polypropylene resin part is molded by injection molding, a better appearance can be obtained as compared with the one molded with a stampable sheet. The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the present invention is embodied as a step for getting on and off the vehicle. However, the application is not limited to this, and it can be applied to various parts. Particularly, for parts requiring high strength and impact resistance, the feature of the present invention is Can be fully utilized.

In the above embodiment, the step for getting on and off is manufactured by injection molding. However, the manufacturing method is not limited to injection molding, and other molding methods such as extrusion molding may be applied. Even in this case, by using the block-based resin as a base, it is possible to sufficiently obtain the characteristic impact resistance.

[0021]

As described above, according to the long glass fiber reinforced polypropylene resin part of the first aspect of the present invention, since polypropylene alone as propylene is added to the polypropylene block reinforced with glass fiber, the strength is significantly reduced. There is no, and the glass fiber firmly adheres to the polypropylene block body to improve the impact resistance,
Therefore, it can be applied to a wide range of applications by satisfying both conflicting demands for improving strength and impact resistance.

According to the long glass fiber reinforced polypropylene resin part of the second aspect of the present invention, not only a good appearance can be obtained by manufacturing by injection molding, but also a polypropylene block body reinforced with glass fiber can be used as a propylene simple substance. Because of the addition of polypropylene, the strength does not decrease so much, and the glass fiber firmly adheres to the polypropylene block body to improve the impact resistance. Therefore, the high strength and impact resistance required for vehicle steps are achieved. The properties can be satisfied together.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a step for getting on and off of an embodiment.

FIG. 2 is a graph showing a change in strength when a base resin and a blend ratio are changed.

FIG. 3 is a graph showing a change in impact resistance when a base resin and a blend ratio are changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Step for getting on and off 2 Step surface 2a Through hole 3 Garnish part

Claims (2)

[Claims] 1. A polypropylene comprising a copolymer of ethylene and propylene arranged as an island layer in a sea layer of polypropylene, and polymerized with propylene alone in a glass long fiber reinforced polypropylene block reinforced by glass fibers. A long glass fiber reinforced polypropylene resin part, characterized by being formed by adding a resin. 2. A polypropylene comprising a copolymer of ethylene and propylene arranged as an island layer in a sea layer of polypropylene, and polymerized by polymerizing propylene alone into a long glass fiber reinforced polypropylene block reinforced by glass fibers. And a long glass fiber reinforced polypropylene resin part formed by injection molding into a vehicle step mold.