JPH11123751A - Production of multi-layer laminated molded body having recycled material layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a multi-layer laminated molded body having a recycled material layer in which even when flow resistance of recycled material is large, it is stably applied and furthermore thickness of respective layers is easily controlled. SOLUTION: Recycling material is charged into at least one selected from a plurality of plasticization units 12, 22. Thermoplastic resin for a skin layer is charged into the other plasticization unit. A molten multi-layer body obtained by coextruding them is fed to a mold and molded. Since this molding differs from injection molding and sandwich molding and resin pressure in the case of extrusion is remarkably low, recycled material mixed with coating, fiber chips and resin excepting olefin-based resin and even recycled material of high viscosity are extruded easily and stably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multilayer laminated molded article, wherein at least one of the multilayer laminated molded articles is a recycled material layer made of a thermoplastic resin.

[0002]

2. Description of the Related Art Resin products are used in a very wide range and in large quantities. However, from the viewpoint of environmental problems or cost reduction, it is important to recycle used resin products or burrs generated during molding, so-called recycling. Have been. Among them, olefin-based resins are attracting attention because they are relatively easy to recycle, and olefin-based resin parts are often used particularly in the field of automobiles that require high recycling. However, resin products recovered from the market or recycled materials produced in the manufacturing process are deteriorated in quality or contain impurities compared to unused raw materials. And poor physical properties are likely to occur. Therefore, by using a recycled material, as one of the molding techniques for directly shaping a product having a shape, by sandwich molding, by forming a multilayer laminated molded body composed of a skin layer made of raw materials and a recycled material layer, Has been addressed.

[0003]

By the way, various kinds of resins are used for resin products according to their uses, and various resin laminates and various fillers are mixed and used. In many cases, for example, even if it is called a recycled material of olefin-based resin, high-viscosity olefin-based resin, paint (coating), glass fiber, fiber such as polyester fiber and nylon fiber, and thermoplastic resin other than olefin-based resin At present, it is often mixed. For that reason,
A recycled material having such a composition generally has a high flow resistance. On the other hand, since sandwich molding based on injection molding and injection molding technology is a technology for extruding a resin through a narrow flow path at a high pressure and molding, when a recycled material having a large flow resistance is applied to these molding methods, the molding becomes impossible. However, even if molding is possible, molding defects are apt to occur frequently, and there are restrictions on the recyclable materials that can be used, and promotion of recycling has been difficult. Also,
In the case of sandwich molding, it is difficult to control the layer thickness structure, particularly to reduce the thickness of the skin layer, so it is not possible to reduce the amount of raw materials used, it is difficult to reduce costs, and the recycling rate of recycled materials Could not increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and can be applied stably even if the flow resistance of the recycled material is large, and furthermore, a multilayer laminate molding having a recycled material layer in which the thickness of each layer can be easily controlled. It is intended to provide a method for producing a body.

[0005]

According to the method of the present invention, a recycled material is charged into at least one of a plurality of plasticizing units, and a thermoplastic resin for a skin layer is added to other plasticizing units. A resin is charged, and a molten multilayer body obtained by co-extruding the resin is supplied to a mold and molded. Here, the thermoplastic resin for the skin layer is an olefin-based resin or a thermoplastic resin compatible with the olefin-based resin, and it is desirable that the recycled material is mainly composed of the olefin-based resin. Further, a skin material may be provided in advance in a mold, and the skin material may be provided on at least a part of the surface of the molded body. Further, as the olefin-based resin or the thermoplastic resin compatible with the olefin-based resin, an olefin-based thermoplastic elastomer or a styrene-α-olefin block copolymer is preferable. Further, as a recycled material, powder obtained by pulverizing a resin molded product can be directly introduced into a plasticizing unit.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The molded article obtained by the production method of the present invention is a multilayer laminated molded article, at least one of which is made of a recycled material,
It has at least one layer made of a new resin material made of a non-recycled material (this layer is called a skin layer). That is, the multilayer laminate molded article has at least a two-layer structure, and may have three or more layers. Depending on the number of layers, the recycled material layer and the skin layer have two or more layers. Of layers. Therefore, in a multilayer structure of three or more layers, there may be a layer structure in which the skin layer is not exposed on the surface.

As the thermoplastic resin for the skin layer, various thermoplastic resins depending on the use are used, and an olefin resin or a thermoplastic resin having good compatibility with the olefin resin is desirable. Examples of such olefin-based resins include ethylene-based resins, propylene-based resins, and mixtures thereof. Examples of the ethylene resin include a high-density polyethylene produced by a medium-low pressure method, a copolymer with an α-olefin, a low-density polyethylene produced by a high pressure method, and a copolymer with various monomers (for example, ethylene-vinyl acetate). And the like. As the propylene-based resin, a propylene homopolymer, a propylene-α-olefin random copolymer, a propylene homopolymer or a propylene-α-olefin random copolymer,
Examples include impact-resistant polypropylene and propylene-based thermoplastic elastomer mixed with propylene copolymer rubber. Examples of the thermoplastic resin compatible with the olefin resin include a styrene-α-olefin block copolymer, and examples thereof include a hydrogenated product of a styrene-butadiene block copolymer and a styrene-isoprene block copolymer. . When a surface of the obtained molded article is provided with a grain pattern or the like to improve appearance characteristics, an olefin (particularly, propylene) thermoplastic elastomer or styrene-α
-Olefin block copolymers and mixtures thereof are preferred. When such an elastomer or the like is used, transferability from a mold can be improved. Further, generation of charge marks on the surface of the molded body can be suppressed. The thermoplastic resin for the skin layer may be used alone or in combination of two or more. Also, talc, glass fiber,
A mixture of fillers such as wood powder can also be used. If necessary, additives such as commonly used stabilizers, flame retardants, processability improvers, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, coloring agents, pigments, etc. may be added. Good. In addition, an excipient may be used for weight reduction. As the thermoplastic resin for the skin layer, a wide range of thermoplastic resins can be used as its MFR (measured at a temperature of 230 ° C. and a load of 2.16 kg in accordance with JIS K 6758). Is preferably 20 to 100 g / 1.
More preferably, it is 0 min. If it is less than 5 g / 10 min, charge marks may be generated on the surface, which is not preferable.

[0008] The recycled material used in the present invention is obtained from various thermoplastic resin products, and among them, those containing an olefin resin as a main component are preferable. As such, for example, various resin parts for automobiles, specifically, a crushed product of a polypropylene bumper, a polyester nonwoven fabric, a polyamide nonwoven fabric, a skin layer of a propylene-based thermoplastic elastomer and a propylene-based resin or glass fiber were contained. A crushed product of an interior component comprising a propylene-based resin base layer, a crushed product of an interior component using a polypropylene-based foam as a cushion layer and a polypropylene-based resin as a cushion layer, a single layer of polyethylene or polyamide or ethylene-vinyl Examples include a laminated polyethylene gasoline tank including a barrier layer such as an alcohol copolymer, or a pulverized product of the burr. The recycled material may be mixed with an olefin-based resin used for the skin layer or a thermoplastic resin having good compatibility with the olefin-based resin for adjusting physical properties.

The manufacturing method of the present invention utilizes a so-called stamping molding method, and an example of a stamping molding machine used in the molding method is shown in FIGS.
In the stamping molding machine of the illustrated example, two extruders 10 and 20 having plasticizing units 12 and 22 are provided on a moving mechanism 30, and the extruders 10 and 20 are connected at their tips to enable multilayer co-extrusion. The die head 32 is provided. In this example, the thermoplastic resin for the skin layer is put into the plasticizing unit 12 of one extruder 10 from the hopper 14 and the recycled material is put into the plasticizing unit 22 of the other extruder 20 from the hopper 24. Is done. The screws of the plasticizing units 12 and 22 are, for example, a single-shaft type or a twin-shaft type. However, it is preferable that the screw in the plasticizing unit 22 into which the recycled material is charged is a biaxial type screw and the groove shape is a dull mage.

As a die head 32 for co-extruding a multilayer body of a skin layer made of a thermoplastic resin for a skin layer and a recycled material layer made of a recycled material, for example, a multilayer T die head or a multilayer cylindrical die head is applied. it can.
Further, it is preferable to provide a shut-off between the extruder and the die to prevent resin dripping. Further, it is preferable to provide a cutter for cutting off the molten multilayer body at the tip of the die head 32. The moving mechanism 30 numerically controls the extruders 10 and 20 to move integrally in the front and rear, right and left, or further up and down, that is, two-dimensionally or three-dimensionally, and moves forward to insert the die head 32 between the molds. Alternatively, the die head 32 is pulled out from between the molds by retreating,
The die head 32 can be arranged at each position in the mold, and the molten multilayer body extruded from the die head 32 can be supplied to each position of the mold. The press molding machine 40 performs compression molding with the upper mold 42 and the lower mold 44, and forms the molten multilayer body supplied from the die head 32 onto the lower mold 44 into a predetermined shape.

In order to obtain a multilayer laminated molded product by this stamping molding machine, a thermoplastic resin for a skin layer is charged into a hopper 14 of a plasticizing unit 12 and a recycled material is charged into a hopper 24 of a plasticizing unit 22. Each of the plasticizing units 12 and 22 is sufficiently plasticized at a predetermined temperature and extrudes a predetermined amount of resin.
And co-extruded as a two-layer laminate of a skin layer made of a thermoplastic resin for a skin layer and a recycled material layer made of a recycled material. At this time, as shown in FIG. 3, the die head 32 moves on the lower mold 44 of the opened press forming machine 40 by the moving mechanism 30, and the co-extruded molten multilayer body 50 is pattern-charged. (Note that FIG. 3
, The upper mold and the like are omitted). On this occasion,
By controlling the extrusion speed in conjunction with the movement of the moving mechanism, it is possible to freely (for example, partially) adjust the thickness of the molded body and the thickness of each layer according to a complicated shape. In addition, the molten multilayer body extruded from the die head may have a skin layer or a recycle material layer on the lower side in contact with the lower mold 44 depending on a target molded body. When a predetermined amount of the molten multilayer body has been supplied, the die head 32 is pulled out from between the dies by the moving mechanism 30, and then the upper die 42 is lowered to perform compression molding. Thus, a multilayer laminated molded body having a predetermined shape is obtained.

In the above-described example, co-extrusion is performed in a two-layer configuration using two extruders. However, the present invention is not limited to this, and co-extrusion is performed using three or more extruders. Is also good. Further, if necessary, a skin material may be provided in advance in a mold, and the skin material may be provided on at least a part of the surface of the molded body. For example, a sheet-shaped skin material made of a polyester nonwoven fabric and foamed polypropylene, or a sheet-shaped skin material made of soft vinyl chloride and foamed polypropylene are arranged on the lower mold 44,
The molten multilayer body is extruded and supplied onto the skin material, and integrated by compression molding, or the skin material is disposed in the upper mold 42, and the molten multilayer body supplied on the lower mold 44 is formed. It can be integrated by compression molding. At this time, the skin material may cover the entire surface of the molded body as necessary, or may be attached to only a part thereof. Further, in the above-described example, the multilayer body is formed by compression molding using a press molding machine. However, the present invention is not limited to this, and it may be formed by vacuum molding or the like.

According to the present invention, since the stamping molding method for extruding the molten resin from the open die head is used, unlike the injection molding or the sandwich molding, the resin pressure at the time of extrusion is extremely low. Can be stably extruded even with a resin composition having a large particle size. As a result, it is possible to easily extrude recycled materials that contain paint, fiber waste, resins other than olefin-based resins, or even high-viscosity recycled materials. It can be reused. In addition, in the case of recycling recycled materials, conventionally, in order to enhance the extrusion performance, the recycled materials should be introduced into the plasticizing unit of the extruder after the recycled materials are pulverized, melted, and pelletized. However, according to the present invention, since it is possible to extrude with a low resin pressure, it is not always necessary to pelletize, and the powder obtained by pulverizing the resin molded product is directly charged into the plasticizing unit of the extruder. Can be molded. Therefore, since a pelletizing step is not required, the manufacturing process can be simplified or the cost can be reduced, and further recycling can be promoted. Further, according to the present invention, it is easy to control the thickness of each layer of the multilayer laminated molded product, and the thickness of the skin layer can be reduced.

[0014]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Molding as described below was performed using the following thermoplastic resin for skin layer and a recycled material. [Thermoplastic resin for skin layer] A-1: Impact resistant random polypropylene MFR; 45 g / 10 min "MK712H" manufactured by Nippon Polyolefin Co., Ltd. A-2: Random polypropylene MFR; 30 g / 10 min Nippon Polyolefin Co., Ltd. "MD770H" A-3: Propylene-based thermoplastic elastomer MFR; 10 g / 10 min Shore A; 70 "P332G" manufactured by Nippon Polyolefin Co., Ltd. However, MFR was measured at a temperature of 230 ° C. and a load of 2.16 kg in accordance with JIS K 6758. .

[Recycled Material] B-1: Recycled material for multi-layer gasoline tank Ultra-high molecular weight polyethylene (“4551H” manufactured by Nippon Polyolefin Co., Ltd.) as HDPE, and polyethylene modified with acid anhydride as modified PE (Nippon Polyolefin (JP)) Co., Ltd. “ER405A”), 6-
Using Nylon (manufactured by Toray Industries, Inc.), HDPE / modified PE / barrier material / modified PE / HDPE = 1200/50
/ 100/50/1200 (μm) 40-mesh pulverized product of a 5-layer plastic gasoline tank. B-2: Recycled material for automotive roof lining A 40 mesh pulverized product of roof lining in which a mixed nonwoven fabric of polyester and 6,6 nylon is laminated on a glass foam-containing polypropylene foam base material. B-3: Recycled material for automobile bumpers A 40-mesh pulverized polypropylene bumper with a coating film applied. B-4: Recycled material for door trim A 40-mesh pulverized door trim obtained by laminating a polypropylene-based thermoplastic elastomer / foamed PP (Toray PEF) on a polypropylene substrate.

Example 1 A multilayer stamping mold shown in FIG. 1 was prepared by using impact-resistant random polypropylene (A-1) as a thermoplastic resin for a skin layer and a recycled material (B-1) from a multilayer gasoline tank as a recycled material. It was molded using a molding machine. The multilayer stamping molding machine used (“FSM450” manufactured by Takahashi Seiki Kogyo Co., Ltd.) is composed of two plasticizing units 1 having a diameter of 75 mmφ installed on a moving mechanism.
A resin supply device having a multi-layer co-extrudable die head 32 having a width of 500 mm at the tip of each of the resin feeders 22 and 22;
Ton of hydraulic press equipment. However, assuming that the target thickness of the skin layer is 0.5 mm, the skin layer lip thickness of the T-die was set to 0.7 mm, and the recycled material layer lip thickness was set to 2.3 mm. 500 × for press molding machine
A 600 mm square, 2.5 mm thick flat plate type was used. A molten multilayer body having a two-layer structure including a skin layer and a recycled material layer is supplied from a die head 32 onto a mold,
Press molding was performed to obtain a multilayer laminated molded product. At this time, the resin pressure at the time of supply was measured with a resin pressure sensor attached in front of the T-die, and the thickness of the skin layer and the recycled material layer of the obtained multilayer laminated molded product was measured at several places, and the average value was measured. I asked. In addition, a crimp pattern was formed on the lower mold, and the transferability to a molded body was evaluated. Good transferability ○,
Very good ones were marked with ◎. Table 1 shows each measurement and evaluation result.
Shown in [Examples 2 to 4] A multilayer laminated molded article was obtained in the same manner as in Example 1 except that the thermoplastic resin for the skin layer and the recycled material were of the combinations shown in Table 1.

Comparative Example 1 A propylene-based thermoplastic elastomer (A-3) was used as the thermoplastic resin for the skin layer, and a recycled material (B-
Sandwich molding was performed using 1). For sandwich molding, a sandwich molding machine composed of two plasticizing units ("ISO350F" manufactured by Toshiba Machine Co., Ltd.)
B "), bottom surface 200 × 200 mm, height 50 m
m, a 2.5 mm thick box type was used. The ratio of the thermoplastic resin for the skin layer and the measurement value of the recycled material is 1: 4,
First, the thermoplastic resin for the skin layer was injected, and then the recycled material was injection molded. [Comparative Example 2] In the same manner as in Comparative Example 1, a sandwich molding machine was used, a propylene-based thermoplastic elastomer (A-3) was used as the thermoplastic resin for the skin layer, and an automobile bumper recycled material (B-3) was used as the recycled material. The thermoplastic resin for the skin layer was first injected, and then the recycled material was injection-molded under the condition that the ratio of the measured values of the thermoplastic resin for the skin layer and the recycled material was 1: 4. Comparative Example 3 Using a sandwich molding machine, a propylene-based thermoplastic elastomer (A-
3) Injection molding was performed using a recycled material (B-3) of an automobile bumper as a recycled material, adjusting injection conditions such as an injection speed and an injection pressure and setting the skin layer to cover the entire recycled material layer at a minimum weighing value. .

[0018]

[Table 1]

As is clear from Table 1, Examples 1-4
In this case, the load on the molding machine was small because the resin pressure during supply was small, and the molding stability was good. Further, the skin layer of the multilayer molded article completely covers the entire surface of the recycled layer, and the thickness of the skin layer is almost equal to the target value (0.5).
mm). In particular, in Examples 3 and 4, the transferability was also extremely excellent. However, in Comparative Example 1, the resin pressure was excessive, the mold clamping force was lost, and the resin could not be fully filled, and burrs and short shots occurred. In Comparative Example 2, molding was possible, but the recycled material broke through the skin layer and was exposed on the surface. In Comparative Example 3, although a multilayer laminated molded article could be obtained, the thickness of the skin layer was considerably thick at 1.5 mm.

[0020]

According to the present invention, unlike the injection molding and the sandwich molding, the resin pressure at the time of extrusion is remarkably low. Highly recyclable materials can be easily and stably extruded, and the restrictions on recycled materials are small, making it possible to reuse recycled materials that were not suitable for reuse. , And can also promote recycling. Also,
Since the powder obtained by pulverizing the resin molded product can be used as it is without pelletizing the recycled material, the manufacturing process can be simplified or the cost can be reduced, and further recycling can be promoted. be able to. Further, according to the present invention, it is easy to control the thickness of each layer of the multilayer laminate molded article, it is possible to reduce the thickness of the skin layer, reduce the amount of raw materials used, and increase the reuse rate of recycled materials. Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a multilayer stamping molding machine.

FIG. 2 is a side view taken along the line II-II of FIG.

FIG. 3 is a side view of a relevant part showing the multilayer stamping molding machine during operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Extruder 12 Plasticizing unit 20 Extruder 22 Plasticizing unit 32 Dice head 40 Press molding machine 50 Melted multilayer body

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // B29K 23:00 105: 26 B29L 9:00 (72) Inventor Masamitsu Yamauchi 2-chome, Yakko 2-chome, Kawasaki-ku, Kawasaki, Kanagawa, Japan No. 2 Montelu JP Corporation Kawasaki Research Laboratory

Claims (5)

[Claims] 1. A molten multilayer body obtained by charging a recycled material into at least one of a plurality of plasticizing units, charging a thermoplastic resin for a skin layer into other plasticizing units, and co-extruding these. A method for producing a multilayer laminated molded product, comprising supplying the mixture to a mold and molding. 2. The method according to claim 1, wherein the thermoplastic resin for the skin layer is an olefin resin or a thermoplastic resin compatible with the olefin resin, and the recycled material is mainly composed of the olefin resin. The method for producing a multilayer laminated molded product according to claim 1. 3. The method for producing a multilayer laminated molded product according to claim 1, wherein a skin material is provided in advance in a mold, and the skin material is provided on at least a part of the surface of the molded product. 4. The olefin resin according to claim 2, wherein the olefin resin or the thermoplastic resin compatible with the olefin resin is an olefin thermoplastic elastomer or a styrene-α-olefin block copolymer. A method for producing a multilayer laminated molded article. 5. The method for producing a multilayer laminated molded product according to claim 1, wherein a powder obtained by pulverizing a resin molded product is charged into the plasticizing unit as the recycled material.