Recycling method for laminate

Abstract

To provide a recycling method for laminate that makes it possible to reuse laminate even containing reinforcing material as recycled material without going through complicated processes.SOLUTION: There is provided a recycling method for laminate 1 which consists of thermoplastic resin sheet 2 laminated onto fiber-reinforced thermoplastic resin sheet 3, the melt flow rate (MFR) of resin in the thermoplastic resin sheet 2 being greater than the MFR of resin which is base material of the fiber-reinforced thermoplastic resin sheet 3. The method includes steps of: placing the laminate 1 into a press device 10 equipped with a mold having a lower die 11 and an adjustable upper die 13; and heating only the upper die 13 which contacts a side of the thermoplastic resin sheet 2 to a temperature equal to or greater than the softening temperature of resin of the thermoplastic resin sheet 2 and pressing the laminate 1 between the lower die 11 and the upper die 13 so as to cause resin of the thermoplastic resin sheet 2 to flow into a receiving tray 12 around the outer periphery of the lower die 11, thereby separating and recovering it from the fiber-reinforced thermoplastic resin sheet 3.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for recycling a laminate.

Background Art

[0002] Generally, polypropylene (PP) is mainly used as a material for automobile bumpers and the like, and it is common to apply a polyurethane paint to this and then paint it to make a product. After using such a product as a bumper or the like in an automobile and recycling it as a recycled material, when the product is melted, coating pieces are mixed in the resin material, resulting in poor fluidity, and problems such as molding defects occurring during injection molding or affecting the appearance of the recycled molded product.

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

[0004] In addition, Patent Document 2 describes an outer panel for an automobile in which a second thermoplastic resin material not containing a reinforcing material is closely laminated on a base material made of a first resin material in which a reinforcing material such as glass fiber is mixed in a matrix made of a thermoplastic resin.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the method of separating the coating film powder as in Patent Document 1 from the resin base material, there is a problem that the number of man-hours is increased and the manufacturing cost of the recycled molded product is increased. Further, when a product containing a reinforcing material such as glass fiber as in Patent Document 2 is reused as a recycled material, in addition to the above coating film, a reinforcing material such as glass fiber is added, which further increases the number of man-hours and the manufacturing cost of the recycled product.

[0007] Therefore, in view of the above problems, an object of the present invention is to provide a method for recycling a laminate that can be easily reused as a recycled material even for a laminate containing a reinforcing material without going through a complicated process.

Means for Solving the Problems

[0008] In order to achieve the above object, the present invention is a method for recycling a laminate in which a thermoplastic resin sheet is laminated on a fiber-reinforced thermoplastic resin sheet, and the melt flow rate of the resin of the thermoplastic resin sheet is larger than the melt flow rate of the resin of the base material of the fiber-reinforced thermoplastic resin sheet. This method includes a step of introducing the laminate into a press device provided with a mold having a lower mold on which the laminate is disposed and an upper mold that can be raised and lowered, and heating and pressing only the mold in contact with the thermoplastic resin sheet side of the laminate to a temperature equal to or higher than the softening temperature of the resin of the thermoplastic resin sheet, and flowing the resin of the thermoplastic resin sheet around the laminate to separate and recover the resin of the thermoplastic resin sheet from the laminate.

Effects of the Invention

[0009] As described above, according to the present invention, since only the thermoplastic resin sheet is heated, by pressing the laminate, only the resin of the thermoplastic resin sheet can be made to flow, and the resin of the thermoplastic resin sheet can be efficiently separated and recovered from the laminate and reused as a recycled material.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiment for Carrying Out the Invention

[0011] Hereinafter, with reference to the accompanying drawings, an embodiment of a method for recycling a laminate according to the present invention will be described.

[0012] The method for recycling the laminate of the present embodiment mainly includes a step of putting a laminate in which a thermoplastic resin sheet is laminated on a fiber-reinforced thermoplastic resin sheet into a press device having a mold with a lower mold and an upper mold, and heating and pressing only the mold in contact with the thermoplastic resin sheet side to a temperature equal to or higher than the softening temperature of the resin of the thermoplastic resin sheet, and separating and recovering the resin of the thermoplastic resin sheet from the fiber-reinforced thermoplastic resin sheet. Hereinafter, the target laminate and each step will be described in detail.

[0013] As shown in FIG. 1, the laminate 1 that is the target of the method of the present embodiment includes a thermoplastic resin sheet 2 and a fiber-reinforced thermoplastic resin sheet 3, and the melt flow rate (MFR) of the resin of the thermoplastic resin sheet 2 is larger than the MFR measured by JIS K 7210 (230 ° C., 2.16 kg load) of the resin that is the base material of the fiber-reinforced thermoplastic resin sheet 3. In addition, it is preferable that characters, symbols, etc. are provided on at least one surface of the laminate so that the surface on the thermoplastic resin sheet 2 side and the surface on the fiber-reinforced thermoplastic resin sheet 3 side of the laminate 1 can be immediately recognized.

[0014] The thermoplastic resin used for the base material of the thermoplastic resin sheet 2 and the fiber-reinforced thermoplastic resin sheet 3 is not particularly limited. For example, polypropylene, polyethylene, foamed polyethylene, polyvinyl chloride, acrylic, polyamide, ABS, PET, PBT, etc. can be used. Among these, polypropylene is preferable also from the viewpoints of moldability, chemical resistance, strength, melting point, etc.

[0015] The fiber of the reinforcing material used in the fiber-reinforced thermoplastic resin sheet 3 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 it may be a woven fabric or a non-woven fabric. As the non-woven fabric, it may be a mat in which single fibers or chopped strands are fixed with glue, or a needle-punched non-woven fabric. Also, long fibers are preferable for the fibers of the reinforcing material. By using long fibers, the rigidity and strength of the laminate can be efficiently improved with a small amount of fibers.

[0016] Such a laminate 1 is put into a press device 10 as shown in FIG. 2. The press device 10 includes a mold having a lower mold 11 on which the laminate 1 is disposed and an upper mold 13 that can move up and down. The press device 10 also includes an annular tray 12 provided on the outer periphery of the lower mold 11 for accommodating the resin flowing from the lower mold 11. Such a press device 10 is loaded as shown in FIG. 2(a) so that the fiber-reinforced thermoplastic resin sheet 3 side of the laminate 1 is in contact with the lower mold 11.

[0017] Then, only the upper mold 13 on the thermoplastic resin sheet 2 side of the laminate 1 is heated. The heating temperature in the press device 10 is not particularly limited as long as it can sufficiently soften the thermoplastic resin sheet 2. For example, it is preferable to heat so that the temperature of the thermoplastic resin sheet 2 is in the range of 180°C to 220°C.

[0018] Next, as shown in Fig. 2(b), the upper die 13 of the press device 10 is lowered to press the laminate 1 between the lower die 11 and the upper die 13. As a result, since the MFR of the resin of the thermoplastic resin sheet 2 is larger than the MFR of the resin that is the base material of the fiber-reinforced thermoplastic resin sheet 3, the viscosities of the resin of the thermoplastic resin sheet 2 and the resin of the base material of the fiber-reinforced thermoplastic resin sheet 3 are different. Therefore, only the resin 2a of the thermoplastic resin sheet 2 flows and runs to the saucer 12 provided on the outer periphery of the lower die 11, and can be separated and recovered from the fiber-reinforced thermoplastic resin sheet 3. The recovered resin 2a of the thermoplastic resin sheet 2 is reused as a recycled material.

[0019] It is preferable that the MFR of the resin that is the base material of the fiber-reinforced thermoplastic resin sheet 3 in the laminate 1 is 0.5 to 10 g / 10 min, and the MFR of the resin of the thermoplastic resin sheet 2 is 20 to 40 g / 10 min. In this way, since it is a range of MFR with a larger difference, the difference in viscosity is also large. Therefore, only the thermoplastic resin sheet 2 can be surely softened and made to flow in the pressing process, and can be efficiently separated and recovered from the fiber-reinforced thermoplastic resin sheet 3.

[0020] Note that the thermoplastic resin sheet 2 of the laminate 1 may contain coating pieces. Even in the case of a laminate in which the thermoplastic resin sheet 2 contains coating pieces, according to the present invention, the coating pieces also flow together with the resin of the thermoplastic resin sheet 2, are separated and recovered from the fiber-reinforced thermoplastic resin sheet 3, and can be reused as a recycled material.

[0021] In FIG. 2, the laminate 1 was put into the pressing device 10, heated, and pressed so that the thermoplastic resin sheet 2 was on the upper side. However, the present invention is not limited to this, and it may be put in, heated, and pressed so that the thermoplastic resin sheet 2 is on the lower side. In this case, by heating only the lower mold 11 to a predetermined temperature, only the resin 2a of the thermoplastic resin sheet 2 flows into the tray 12, separates, and can be recovered in the same manner as when the thermoplastic resin sheet 2 is on the upper side. However, since heat is transferred to the fiber-reinforced thermoplastic resin sheet 3 side from the time when the laminate 1 is placed in the pressing device 10, especially when the MFR of the resin is close, there is a possibility that the resin of the fiber-reinforced thermoplastic resin sheet 3 also flows together. Therefore, it is more preferable to place the thermoplastic resin sheet 2 on the upper side as shown in FIG. 2.

[0022] In addition, the laminate 1 is not limited to two layers of the thermoplastic resin sheet 2 and the fiber-reinforced thermoplastic resin sheet 3, and may be made into three layers with two fiber-reinforced thermoplastic resin sheets 3 sandwiching the thermoplastic resin sheet 2, or in the reverse configuration, with two thermoplastic resin sheets 2 sandwiching the fiber-reinforced thermoplastic resin sheet 3, or even four layers or more.

Explanation of Reference Numerals

[0023] 1 Laminate 2 Thermoplastic resin sheet 2a Resin flowed from the thermoplastic resin sheet 3 Fiber-reinforced thermoplastic resin sheet 10 Pressing device 11 Lower mold 12 Tray 13 Upper mold

Claims

1. A method for recycling a laminate in which a thermoplastic resin sheet is laminated on a fiber-reinforced thermoplastic resin sheet, wherein the melt flow rate of the resin of the thermoplastic resin sheet is greater than the melt flow rate of the resin that is the base material of the fiber-reinforced thermoplastic resin sheet, and this method comprises a step of loading the laminate into a press device equipped with a mold having a lower mold on which the laminate is placed and an upper mold that can move up and down; a step of heating and pressing only the mold in contact with the thermoplastic resin sheet side of the laminate to a temperature equal to or higher than the softening temperature of the resin of the thermoplastic resin sheet, and causing the resin of the thermoplastic resin sheet to flow around the laminate to separate and recover the resin of the thermoplastic resin sheet from the fiber-reinforced thermoplastic resin sheet A method for recycling a laminate including the above steps.

2. The method for recycling a laminate according to claim 1, wherein the fiber-reinforced thermoplastic resin sheet side of the laminate is placed on the lower mold, and the upper mold in contact with the thermoplastic resin sheet side is heated and pressed.

3. The fiber-reinforced thermoplastic 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 thermoplastic resin sheet contains polypropylene and a coating film piece and has a melt flow rate measured by JIS K 7210 (230 °C, 2.16 kg load) of 20 to 40 g / 10 min The method for recycling a laminate according to claim 1 or 2.

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