JPH07117588A - Bumper for automobile and manufacture of bumper for automobile - Google Patents

Abstract

PURPOSE:To provide a bumper for an automobile by reusing a polyolefine resin made mounding collected article for a bumper core layer. CONSTITUTION:Polypropylene and propylene-ethylene rubber are used as one of a polyolefine resin component on both outsides of a core layer 4 of a raw material made by crushing a collected polypropylene made bumper coated with a two liquid urethane coating material as one kind of coating material of a thermosetting resin coating material by a crusher and refining its film grain diameter as 0.3mm or smaller. A bumper 1 for an automobile is constituted by forming a skin layer 2 with the raw material added with talc, pigment, a shading agent and a heat stabilizing agent, inserting the skin layer 2 in the core layer 4 at a part adjacent to a cavity entrance and laminating them in five layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile bumper having a high mechanical strength, in which a molded product recovered from a coated polyolefin resin composition is reused as a core layer of an automobile bumper.

[0002]

2. Description of the Related Art Polyolefin resin compositions having excellent mechanical strength, thermal strength, moldability and the like are used in bumpers for automobiles, and the bumper surface is coated in order to enhance its commercialability. There is.

When the polyolefin resin bumper for automobiles thus coated is reused as a recycling resource, it is difficult to separate the coating film from the base material without using a liquid agent that causes pollution. As described in Kaihei 4-267114, a coated polyolefin resin bumper reclaim material for automobiles is crushed, and the crushed product is heated and melted by an extruder, and the reclaimed bumper material is used as a core material. Then, multilayer injection molding was performed using another polyolefin resin composition as a skin material.

To carry out this multi-layer injection molding, Japanese Patent Application Laid-Open No.
As described in JP-A-353414, a soft resin material that forms a skin layer is first injected into a cavity of a mold, and then a hard resin material that forms a core layer is injected, and a core layer is formed between the skin layers. Was formed into a sandwich.

[0005]

When the method described in Japanese Patent Application Laid-Open No. 4-353414 is applied to bumper injection molding, 2
Different types of resin are supplied to the mold cavity inlet with different timings by different extruders, so when bumper injection molding is completed and the next new bumper injection molding is started. In the mold cavity, the core material of the recycled bumper remaining in the molding material supply passage from the outlet confluence of both extruders to the mold cavity inlet is mixed with the virgin skin material that dislikes mixing of different materials, As a result, the bumper reclaimed material containing the coating film mixes with the skin layer of the next bumper molded product, and the impact resistance of the bumper skin layer that bears the bending strength is reduced, and the appearance is also reduced. Was significantly reduced.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an improvement of a bumper for an automobile which overcomes the above problems and comprises a polyolefin resin composition coated with a thermosetting resin coating film. In a bumper for an automobile having a core layer using a recovered molded product and a skin layer made of another resin formed on an outer peripheral portion of the core layer, a core of the core layer is formed in at least a part of the bumper. A resin layer other than the skin layer is formed in the portion.

Since the present invention is configured as described above, at least a part of the automobile bumper has five layers including the central skin layer, the core layers on both sides of the central skin layer, and the outer skin layers on both outer sides of the core layer. As a result of the laminated structure, the core layer, which is inferior in appearance, is not exposed on the bumper surface, and it is possible to avoid lowering the commercial property, and improve the mechanical strength, especially the bending strength, by the laminated structure of 5 layers. Can be expected.

According to the present invention, another resin constituting the skin layer according to claim 1 is injected into the cavity of the mold by one of the extruders, and then the resin constituting the core layer according to claim 1. The composition is injected into the mold cavity by the other extruder, and finally the other resin constituting the skin layer is injected by the one extruder to produce a bumper for automobiles. By applying such a manufacturing method, after the injection of the resin composition constituting the core layer is completed, the molding material supply passage from the outlet merging portion of the two extruders to the mold cavity inlet is formed. The remaining bumper recycled core material is pushed into the mold cavity by the other resin injected from the one extruder in the last injection molding, and at the end of the injection molding operation, the exits of the two extruders From the junction Since the molding material supply passage up to the mold cavity inlet can be filled with the other resin, at the start of the next bumper molding, another resin newly injected into the mold cavity by one of the extruders can be filled. It is possible to prevent the recycled core material of the bumper mixed with the thermosetting resin coating film from being mixed, and the bumper skin layer is made of only another resin.

Since the skin layer of the newly molded automobile bumper is composed of only another resin, the bumper recycled core material that impairs the appearance is not exposed on the bumper skin layer, and the appearance is deteriorated. In addition, the impact resistance of the bumper outer surface layer, which bears the bending strength most efficiently, is improved, and the bending strength of the bumper can be maintained at a high level.

According to the present invention, the material injected into the mold cavity immediately before the completion of injection molding of the automobile bumper and the material injected into the mold cavity at the start of the next injection molding of the automobile bumper. Are the same, the injection molding work of the automobile bumper can be continued smoothly.
Productivity can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below. 1 shown in FIG. 1 to which the present invention is applied,
The front bumper has a cross-sectional shape formed as shown in FIG. The skin layer 2 of the automobile bumper 1 is a virgin material, and polypropylene and propylene-ethylene rubber are used as one of the polyolefin-based resin compositions, to which talc, a pigment, a light stabilizer, and a heat stabilizer are added. Melt and knead with a granulator, remove coarse particles through a mesh of 80 to 100 mesh, cut a linear one through a thin tube with an inner diameter of about 1 mm to a length of 1 to several mm, and pellets for the skin layer 3 is granulated, and the skin layer pellets 3 are used as a raw material.

The core layer 4 of the automobile bumper 1 is granulated after crushing with a crusher a recovered polypropylene bumper coated with a two-component urethane paint as one type of thermosetting resin paint. When melting and kneading with a machine, an organic compound in which 2 to 20% by weight of olefin as a main chain of the recovered bumper is graft-polymerized or copolymerized with carboxyl group, acrylic group, OH group, glycidyl group or added to both ends Is used for the skin layer 2 by adding a compatibilizing agent consisting of the following to refine the coating particle size to 0.3 mm or less and to enhance the adhesion between the surface of the coating particle and the contact surface of polypropylene adjacent thereto. The core layer pellets 5 having substantially the same size as the skin layer pellets 3 are granulated, and the core layer pellets 5 are used as a raw material.

The polypropylene-based resin composition of the skin layer pellets 3 and the core layer pellets 5 was polypropylene and propylene-ethylene rubber, but it was polyethylene, poly-4-methylpentene-1, polybutene, ethylene-butene rubber, EPDM. You may use rubber etc. by 1 type or in mixture of 2 or more types.

The pellets 3 for the skin layer and the pellets 5 for the core layer are filled in the cylinders 10 and 11 from the hoppers 8 and 9 of the extruders 6 and 7 shown in FIG. 3 and extruded in the following steps. Perform molding.

A heater (not shown) is provided on the outer circumference of the cylinders 10, 11 of the extruders 6, 7 so that the screws 12, 13 in the cylinders 10, 11 are driven to rotate by a prime mover (not shown), respectively. Thus, the skin layer pellets 3 and the core layer pellets 5 filled in the cylinders 10 and 11 are heated and melted.

First, as shown in FIG. 3, the screw 12 in the cylinder 10 is rotationally driven to rotate the screw 10 in the cylinder 10 by 200 °.
The skin layer material 14 heated and melted to C is transferred from the confluence section 16 to the mold 18
It is injected into the cavity 19 via the inlet 20 of the cylinder, and when the injection amount reaches approximately half the volume of the cavity 19, the rotation of the screw 12 is stopped and the skin layer material 14 from the inside of the cylinder 10 is stopped.
Of the skin layer material 14 may be stopped, and in some cases, the rotation of the screw 12 may not be stopped to continue the injection of the skin layer material 14 from the inside of the cylinder 10.

Next, as shown in FIG. 4, when the screw 13 in the cylinder 11 is rotationally driven and the core layer material 15 melted in the cylinder 11 is injected from the confluent portion 16 into the cavity 19, the cavity 19 is already formed. The core layer material 15 penetrates into the skin layer material 14 injected into the core layer 4, and the skin layer 2 is formed on both sides of the core layer 4.
Are placed.

Finally, as shown in FIG. 5, the extruder 6
Is operated again, and the molten skin layer material 14 in the cylinder 11 is injected from the confluence section 16 into the cavity 19, so that the skin layer material 14 enters the core layer material 15 and the vicinity of the inlet 20 of the cavity 19 ( 2 is located below the automobile bumper 1), the outer skin layer 2, the core layer 4, the outer skin layer 2, the core layer 4, and the outer skin layer 2 and 5 layers are laminated from the outer surface of the automobile bumper 1. To be done.

In the automobile bumper 1 shown in the drawing, the skin layer 2 having high mechanical strength such as impact resistance is disposed in a sandwich form on the outer side of the core layer 4 having lower mechanical strength than that, so that the automobile is This can effectively bear the bending load applied to the vehicle bumper 1.

Further, since the core layer 4 does not exist on the outer surface of the automobile bumper 1, the particles of the thermosetting resin coating film in the core layer 4 are not exposed to the surface, and the automobile bumper 1 Has a smooth surface, and the coating film applied on it has a smooth surface, giving it a good appearance, and using a pretreatment agent (111-trichloroethane), which has been conventionally required for painting, It is possible to select a material that does not need to degrease the surface of the vehicle bumper 1, which has a favorable effect in terms of environmental protection and can reduce cost.

Further, when the injection molding of the automobile bumper 1 is completed, the core layer material 15 does not exist in the molding material supply passage 17 from the confluence portion 16 to the inlet 20 of the cavity 19, and the skin layer material 14 is present.
Therefore, when the skin layer material 14 is injected from the extruder 6 into the cavity 19 of the mold 18 in order to start the next injection molding operation of the bumper 1 for an automobile, it remains in the previous injection molding operation. The skin layer material 14 can be directly injected from the extruder 6 without removing the formed skin layer material 14. As a result, the molding work efficiency can be greatly improved, and the core layer material 15 can be formed on the skin layer 2. Since it does not mix,
The mechanical strength of the automobile bumper 1 can be maintained at a high level.

Moreover, near the inlet 20 of the cavity 19,
Since the skin layers 2 to 3 and the core layer 4 are alternately laminated with two layers, the mechanical strength in the vicinity thereof is much higher.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a state in which a bumper according to an exemplary embodiment of the present invention is mounted on a front portion of an automobile.

FIG. 2 is a cross-sectional side view cut along the line II-II of FIG.

FIG. 3 is an explanatory view illustrating a first step of injection molding of the present invention.

FIG. 4 is an explanatory diagram illustrating a second step of the injection molding.

FIG. 5 is an explanatory diagram illustrating a third step of the injection molding.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Automotive bumper, 2 ... Skin layer, 3 ... Skin layer pellets, 4 ... Core layer, 5 ... Core layer pellets, 6, 7 ... Extruder, 8, 9 ... Hopper, 10, 11 ... Cylinder, 12 , 13 ... screw, 14 ... skin layer material, 15 ... core layer material, 16 ... merging part, 17 ... molding material supply passage, 18 ... mold, 19 ... cavity, 20 ... inlet.

Front Page Continuation (72) Inventor Tatsuya Itakura 1-4-1 Chuo, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute

Claims (2)

[Claims] 1. A core layer using a recovered product of a molded product of a polyolefin resin composition coated with a thermosetting resin coating film, and another resin formed on the outer peripheral portion of the core layer. In an automobile bumper having a skin layer made of,
A bumper for an automobile, wherein at least a part of the bumper has another resin layer of the skin layer formed on the core portion of the core layer. 2. The other resin constituting the skin layer according to claim 1 is injected into the cavity of the mold with one extruder, and then the resin composition constituting the core layer according to claim 1 is injected. A car bumper is manufactured by injecting the resin into the cavity of the mold with the other extruder, and finally with the other resin constituting the skin layer with the one extruder. Bumper manufacturing method.