Recycled formed product, method of manufacturing the same, and undercover for vehicle

Abstract

To provide a recycled formed product that does not require complicated steps, and can suppress troubles occurring in a forming step, and a method of manufacturing the same and an undercover for a vehicle.SOLUTION: A method of manufacturing a recycled formed product comprises the steps of: crushing a resin product applied with a coating on an injection-formed product of polypropylene to obtain a crushed material; melting and extrusion-processing the same to form an intermediate formed-body sheet 3; laminating the intermediate formed-body sheet 3 on a fiber-reinforced resin sheet 4 containing an extruded formed product of polypropylene as a base material and heating the laminated body sheet 5 with a preheater device; and thereafter conveying the laminated body sheet to a press-forming device, and press-forming it to obtain the recycled formed product. In the recycled formed product, an MFR of the fiber-reinforced resin sheet is 0.5 to 10 g / 10 min, and an MFR of the intermediate formed-body sheet is 20 to 40 g / 10 min. An undercover for a vehicle comprises the recycled formed product, with the intermediate formed-body sheet side positioned on a vehicle side.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to recycled molded products, a method for manufacturing the same, and an under cover for a vehicle.

Background Art

[0002] Generally, polypropylene (PP) is mainly used as a material for automobile bumpers and the like, and it is common to apply polyurethane paint by spraying to form a product. After using such a product such as a bumper in an automobile and recycling it as a recycled material, coating film pieces are mixed in the molten resin material of the product, so there are problems such as molding defects during injection molding or affecting the appearance of the recycled molded product.

[0003] Therefore, Patent Document 1 describes a method for recycling resin products in which a coated resin product is pulverized and then further finely pulverized, the fine powder is separated into a resin base material and coating film powder by a specific gravity difference, then only the resin base material is recycled, and then a resin product is molded using the recycled resin material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the method of separating coating film powder from a resin base material as in Patent Document 1 has a problem that it takes a lot of man-hours and increases the manufacturing cost of recycled molded products.

[0006] Therefore, in view of the above problems, an object of the present invention is to provide a recycled molded product, a method for manufacturing the same, and a vehicle under cover that can suppress defects generated in the molding process without going through complicated processes.

Means for Solving the Problems

[0007] In order to achieve the above object, as one aspect of the present invention, there is provided a method for manufacturing a recycled molded product, the method including: a step of pulverizing a resin product coated on an injection molded product of polypropylene to obtain a pulverized product; a step of melting the pulverized product and extruding it to form an intermediate molded body sheet; a step of heating a laminated sheet in which the intermediate molded body sheet is laminated on a fiber reinforced resin sheet containing an extrusion molded product of polypropylene as a base material with a preheater device; and a step of conveying the heated laminated sheet to a press molding device and press molding it to obtain a recycled molded product.

[0008] Further, as another aspect of the present invention, there is provided a recycled molded product in which an intermediate molded body sheet is laminated on a fiber reinforced resin sheet, the fiber reinforced resin sheet contains polypropylene as a base material, and has a melt flow rate measured by JIS K 7210 (230°C, 2.16 kg load) of 0.5 to 10 g / 10 min, and the intermediate molded body sheet contains polypropylene and coating pieces and has a melt flow rate measured by JIS K 7210 (230°C, 2.16 kg load) of 20 to 40 g / 10 min.

[0009] Further, as another aspect of the present invention, there is provided a vehicle under cover including the above recycled molded product, with the intermediate molded body sheet side located on the vehicle side.

Effects of the Invention

[0010] According to the present invention as described above, by melting and extruding a crushed material containing painted pieces to form an intermediate molded sheet, laminating the intermediate molded sheet on a fiber-reinforced resin sheet and heating it, and then press molding it, it is possible to provide a recycled molded product that can suppress problems occurring in the molding process without going through complicated processes, a method for manufacturing the same, and an under cover for a vehicle.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0012] Hereinafter, with reference to the accompanying drawings, an embodiment of a recycled molded product, a method for manufacturing the same, and an under cover for a vehicle according to the present invention will be described.

[0013] The method for manufacturing a recycled molded product according to the present embodiment mainly includes a crushing step of crushing a resin product obtained by painting an injection molded product of polypropylene, an extrusion step of melting the obtained crushed material and extruding it to form an intermediate molded sheet, a heating step of laminating this intermediate molded sheet on a fiber-reinforced resin sheet containing an extrusion molded product of polypropylene as a base material to form a laminated sheet and heating it with a preheater device, and a press molding step of transporting the heated laminated sheet to a press molding device and press molding it to obtain a recycled molded product. Each step will be described in detail below.

[0014] The pulverization process can use known wet or dry pulverization methods for recycling resin products as recycled materials. For example, a pulverizer such as a crusher or grinder for uniaxial or biaxial plastic parts can be used alone or in combination of two or more to perform pulverization. The average particle size of the resulting pulverized material is preferably, but not limited to, 20 mm or less. The lower limit of the average particle size of the pulverized material is preferably, but not limited to, 2 mm or more.

[0015] In this embodiment, a resin product with a coating applied to an injection-molded product of polypropylene is pulverized as it is, and without removing the coated pieces from the obtained pulverized material, it is directly used as a recycled material in the extrusion process. By setting the average particle size to 20 mm or less, even if coated pieces are contained in the pulverized material, extrusion can be performed without problems. Also, when the average particle size is less than 2 mm, it becomes difficult to handle the pulverized material. Note that, as a pretreatment for the pulverization process, a pulverization process of pulverizing the resin product with a crusher to a particle size of 20 mm or more may be performed.

[0016] The extrusion process can be performed, for example, using the extrusion device 10 shown in FIG. 1. The pulverized material 1 obtained above is fed from the hopper 11, heated and melted in the extruder 12, and kneaded and extruded by a screw (not shown) in the extruder 12 to send the plasticized polypropylene resin containing the coated pieces to the tip of the extruder 12. Then, it is extruded from the T-die 13 at the tip of the extruder 12 to obtain a film-shaped extruded molded body 2. The extruded molded body 2 is cooled by a plurality of cooling rollers 14 and then cut to a predetermined length by a cutter 15 to obtain an intermediate molded body sheet 3.

[0017] The intermediate molded body sheet 3 preferably has a melt flow rate (MFR) measured by JIS K 7210 (230 °C, 2.16 kg load) of 20 to 40 g / 10 min. By setting the MFR within such a range, the intermediate molded body sheet 3 can be sufficiently softened in the heating process of the subsequent process.

[0018] The heating process and the press forming process can be carried out, for example, using the preheater device 20 and the press forming machine 30 shown in FIG. 2. First, as shown in FIG. 2(a), the intermediate molded body sheet 3 obtained above is placed on the fiber reinforced resin sheet 4 to produce a laminate sheet 5. Then, as shown in FIG. 2(b), this laminate sheet 5 is introduced into the preheater device 20 and passed between the lower hot plate 21 and the upper hot plate 22 to heat the laminate sheet 5, obtaining a heated laminate sheet 6.

[0019] By heating the intermediate molded body sheet 3 as the laminate sheet 5 in this way, it is possible to prevent the problems that occur when the intermediate molded body sheet 3 is heated alone. When the intermediate molded body sheet 3 is heated alone, when it is transported from the preheater device 20 to the subsequent press forming device 30, the intermediate molded body sheet 3 stretches and deforms due to its own weight during transportation, twists or folds, resulting in problems such as dimensional errors in press forming. On the other hand, by heating as the laminate sheet 5, the intermediate molded body sheet 3 is held by the fiber reinforced resin sheet 4 even at a high temperature, so it is possible to prevent the problems that occur during transportation. Furthermore, by heating as the laminate sheet 5 in this way, the heating temperature can be increased to sufficiently soften the intermediate molded body sheet 3, so the press formability can be improved.

[0020] The fiber reinforced resin sheet 4 contains an extruded product of polypropylene as a base material, and preferably has a melt flow rate measured by JIS K 7210 (230 °C, 2.16 kg load) of 0.5 to 10 g / 10 min. By setting the MFR within such a range, excessive softening of the fiber reinforced resin sheet 4 in the heating process can be suppressed, and the heated laminate sheet 6 can be transported from the preheater device 20 to the press forming device 30 without problems.

[0021] The fiber of the reinforcing material used for the fiber-reinforced resin sheet 4 is not particularly limited as long as it does not soften when heated to a high temperature. For example, glass fiber, carbon fiber, aramid fiber, metal fiber, and plant fiber can be used alone or in combination of two or more. The form of the reinforcing material is not particularly limited and may be a woven fabric or a non-woven fabric. As the non-woven fabric, a mat in which single fibers or chopped strands are fixed with an adhesive or a needle-punched non-woven fabric may be used. Further, since the laminate sheet 5 is formed by hot pressing, compared with injection molding, fibers of long fibers can be used. By using long fibers, the rigidity and strength of the recycled molded product can be efficiently improved with a small amount of fibers.

[0022] The heating temperature in the preheater device 20 is not particularly limited as long as it can sufficiently soften the intermediate molded body sheet 3 of the laminate sheet 5. For example, it is preferable to heat so that the temperature of the laminate sheet 5 is in the range of 150°C to 180°C.

[0023] In addition, in FIG. 2(b), it is shown that the laminate sheet 5 is heated by the preheater device 20 with the intermediate molded body sheet 3 on the upper side, but the present invention is not limited to this, and it may be heated with the intermediate molded body sheet 3 on the lower side. This is because the polypropylene resins of the intermediate molded body sheet 3 and the fiber-reinforced resin sheet 4 of the laminate sheet 5 melt together by heating, so that the heated laminate sheet 6 can be conveyed from the preheater device 20 to the press molding device 30 without any problem even if the intermediate molded body sheet 3 is on the lower side.

[0024] Further, the laminate sheet 5 is not limited to two layers of the intermediate molded body sheet 3 and the fiber-reinforced resin sheet 4, and may be three layers in which the intermediate molded body sheet 3 is sandwiched between two fiber-reinforced resin sheets 4, or in the reverse configuration, the fiber-reinforced resin sheet 4 may be sandwiched between two intermediate molded body sheets 3 to form three layers, or further, four layers or more.

[0025] Next, as shown in Fig. 2(b), the above-mentioned heated laminate sheet 6 is conveyed from the preheater device 20 to the press molding device 30 and loaded. In the press molding device 30, a lower mold 31 and an upper mold 33 at room temperature are installed. The lower mold 31 is fixedly attached, and the upper mold 32 is attached so as to be movable up and down. The lower mold 31 and the upper mold 32 are molds that can be formed into the shape of, for example, an under cover for a vehicle. By pressing and molding the heated laminate sheet 6 with the lower mold 31 and the upper mold 32, a recycled molded product formed into a predetermined shape can be obtained.

[0026] In this way, by forming the pulverized material containing paint pieces by extrusion instead of injection molding and then heating and press molding, a recycled molded product can be obtained without problems such as molding defects even if paint film pieces are mixed in.

[0027] Note that in order to be able to apply characters, symbols, etc. to either the surface of the intermediate molded body sheet 3 side or the surface of the fiber-reinforced resin sheet 4 side of the heated laminate sheet 6, it is preferable that either the lower mold 31 or the upper mold 32 has irregularities for applying the above-mentioned characters, symbols, etc. Thereby, it is possible to easily distinguish the front and back of the obtained recycled molded product, that is, whether it is the intermediate molded body sheet 3 side or the fiber-reinforced resin sheet 4 side.

[0028] Next, the recycled molded product of the present embodiment will be described. The recycled molded product of the present embodiment can be obtained by the above manufacturing method. That is, an intermediate molded body sheet is laminated on a fiber-reinforced resin sheet. The fiber-reinforced resin sheet contains polypropylene as a base material and has a melt flow rate measured by JIS K 7210 (230°C, 2.16 kg load) of 0.5 to 10 g / 10 min. The intermediate molded body sheet contains polypropylene and paint film pieces and has a melt flow rate measured by JIS K 7210 (230°C, 2.16 kg load) of 20 to 40 g / 10 min.

[0029] The recycled molded product of this embodiment contains paint pieces but has excellent moldability. Further, by laminating the intermediate molded body sheet and the fiber-reinforced resin sheet, the thickness of the recycled molded product can be increased while suppressing the amount of fibers such as glass fibers of the reinforcing material, and the rigidity of the recycled molded product can be improved.

[0030] Next, the vehicle under cover of this embodiment will be described. The vehicle under cover of this embodiment includes the above-described recycled molded product, and the intermediate molded body sheet side is located on the vehicle side. The vehicle under cover is a component that covers the underside of the vehicle. Since the fiber-reinforced resin sheet is on the outside of the vehicle, the density of the reinforcing material such as glass fibers can be increased on the outside of the vehicle where strength is required, and the chipping resistance can be improved. Further, since the intermediate molded body sheet is on the vehicle side, the paint film pieces contained in the intermediate molded body sheet are less likely to come out to the outside and are hidden by the fiber-reinforced resin sheet, so that appearance problems can be solved.

Explanation of Signs

[0031] 1 Crushed material 2 Extruded molded body 3 Intermediate molded body sheet 4 Fiber-reinforced resin sheet 5 Laminated body sheet 6 Heat-laminated body sheet 10 Extrusion processing device 12 Extruder 13 T-die 14 Cooling roller 15 Cutter 20 Preheater device 30 Press molding device

Claims

1. A step of pulverizing a resin product obtained by coating an injection-molded product of polypropylene to obtain a pulverized product; A step of melting the pulverized product and extruding it to form an intermediate molded sheet; A step of heating a laminated sheet in which the intermediate molded sheet is laminated on a fiber-reinforced resin sheet containing an extrusion-molded product of polypropylene as a base material with a preheater device; A step of conveying the heated laminated sheet to a press molding device and press molding it to obtain a recycled molded product A method for manufacturing a recycled molded product including these steps.

2. The method for manufacturing a recycled molded product according to Claim 1, wherein at the time of press molding, unevenness is imparted to one surface of the laminated sheet by a mold.

3. The fiber-reinforced resin sheet has a melt flow rate measured by JIS K 7210 (230 ° C., 2.16 kg load) of 0.5 to 10 g / 10 min, The method for manufacturing a recycled molded product according to Claim 1 or 2, wherein the intermediate molded sheet has a melt flow rate measured by JIS K 7210 (230 ° C., 2.16 kg load) of 20 to 40 g / 10 min.

4. A recycled molded product in which an intermediate molded sheet is laminated on a fiber-reinforced resin sheet, The fiber-reinforced resin sheet contains polypropylene as a base material and has a melt flow rate measured by JIS K 7210 (230 ° C., 2.16 kg load) of 0.5 to 10 g / 10 min, The intermediate molded sheet contains polypropylene and coating pieces and has a melt flow rate measured by JIS K 7210 (230 ° C., 2.16 kg load) of 20 to 40 g / 10 min Recycled molded product.

5. An underbody cover for a vehicle including the recycled molded product according to Claim 4, wherein the intermediate molded sheet side is located on the vehicle side.

Images