JP4278074B2 - Synthetic resin composite molded body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthetic resin composite molded article in which a foam molded article is inserted into an inner surface of a hollow body made of synthetic resin, which is preferably used as a box, a panel, an automobile part, or the like.
[0002]
[Prior art]
Synthetic resin composite molded bodies composed of a hollow molded body and a synthetic resin foam molded body injected and molded into the hollow molded body have conventionally been used as a returnable box for transporting fresh fish and the like together with ice and toilet water. It has been used as automobile parts such as dew-proof tanks, bumpers and interior materials for storage. For example, a synthetic resin composite molded body in which a urethane resin foam is injected into a hollow molded body made of ABS resin is widely known.
[0003]
However, conventionally used synthetic resin composite molded articles have a problem in recyclability and are insufficient in that resources are effectively used. That is, most of the conventional molding methods for synthetic resin composite moldings apply blow molding, and after molding a hollow molding, a synthetic resin foam is injected into the molding method. Adopted. Accordingly, since the foam is cured by heat generation inside the hollow molded body, the conventional synthetic resin composite molded body is formed by integrating the synthetic resin foam molded body molded inside the hollow molded body and the hollow molded body. As being bonded to each other.
[0004]
As a result, for example, to recycle and re-pelletize synthetic resin composite moldings composed of different resins such as ABS resin hollow moldings and urethane resin foams, as synthetic resins with uniform physical properties, respectively. It was necessary to separate the hollow molded body and the foam molded body, which were strongly bonded and integrated. Separation of such a hollow molded product and the foamed molded product requires a great deal of labor and cost, so that it was practically impossible to recycle.
[0005]
[Problems to be solved by the invention]
The present invention is a synthetic resin composite molded body that can easily separate a hollow molded body and a synthetic resin foam molded body, and is excellent in workability at the time of recycling, and the cost of recycling is low. The purpose is to provide a body.
[0006]
[Means for Solving the Problems]
The synthetic resin composite molded body of the present invention has a 5% compressive strength of 0.1 to 0.1 on the inner surface of a 0.2 to 7 mm thick hollow molded body formed by bonding a plurality of molded divided bodies made of synthetic resin to each other. are interpolated without synthetic resin foam molded article of 30 kgf / cm ² is adhered, foam moldings by and at least a portion of the synthetic resin foam molded body is in close contact with the inner surface of the hollow molded body is fixed It is characterized by being.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partially cutaway perspective view showing an example of a synthetic resin composite molded body (hereinafter referred to as “composite molded body”) of the present invention, FIG. 2 is a longitudinal sectional view, 1 is a composite molded body, 2 Is a hollow molded body, 3 is one divided body constituting the hollow molded body, 4 is another divided body constituting the hollow molded body, 5 is an adhesive portion between the divided body 3 and the divided body 4, 6 is a synthetic resin foam molded body (hereinafter referred to as “foam molded body”), 7 is an inner surface of a hollow molded body in which a part of the foam molded body is in close contact, and 8 is a foam molded body and a hollow molded body. Space portions formed between the inner surface 7 and the inner surface 7 are shown.
[0008]
The divided bodies 3 and 4 constituting the hollow molded body 2 of the present invention are made of synthetic resin. Examples of the synthetic resin include polyvinyl chloride resins such as polyvinyl chloride, polystyrene resins such as polystyrene, polyolefin resins such as polyethylene resins and polypropylene resins, acrylic resins such as polymethyl methacrylate, and polycarbonate resins. A thermoplastic resin etc. are mentioned.
[0009]
Among the thermoplastic resins, polystyrene resins and polyolefin resins are preferable because they are excellent in economic efficiency and recyclability.
Specific examples of the polystyrene resin include polystyrene, impact-resistant polystyrene, acrylonitrile-butadiene-styrene copolymer, and a copolymer of styrene and methyl methacrylate or acrylonitrile.
[0010]
Specific examples of the polyolefin-based resin include, for example, low-density polyethylene, high-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, ethylene-propylene block copolymer, ethylene-propylene random copolymer, An ethylene-butene random copolymer, an ethylene-vinyl acetate copolymer, an ethylene-methyl methacrylate copolymer, an ionomer resin in which molecules of the ethylene-methacrylic acid copolymer are crosslinked with metal ions, a propylene homopolymer, propylene -Ethylene random copolymer, propylene-ethylene block copolymer, propylene-butene random copolymer, polybutene, polypentene, propylene-ethylene-butene terpolymer, propylene-acrylic acid copolymer, propylene-acrylic acid Copolymer Propylene - maleic anhydride copolymer and the like. A copolymer of an olefin monomer such as ethylene, propylene, butene, or pentene and a monomer such as styrene that can be copolymerized with the monomer can also be used. A synthetic resin obtained by mixing a plurality of the above resins can also be used.
[0011]
Among the synthetic resins, polyolefin resins are particularly preferable because they are excellent in heat resistance, chemical resistance, and oil resistance and can be easily recycled. Specifically, for example, polyethylene resins such as low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, linear ultra-low density polyethylene, propylene homopolymer, various propylene-ethylene copolymers. Examples thereof include polypropylene resins such as polymers, propylene-butene copolymers, and propylene-ethylene-butene terpolymers.
[0012]
The hollow molded body 2 of the present invention is constituted by a plurality of divided bodies of the above synthetic resins. The hollow molded body 2 shown in FIGS. 1 and 2 includes a divided body 3, a divided body 4, and an adhesive portion 5. However, the number of divided bodies to be used is not limited, and the size and shape of the composite molded body The hollow molded body 2 can be formed using a plurality of divided bodies determined according to the above.
[0013]
The plurality of divided bodies 3 and 4 are preferably made of the same synthetic resin, but different types of synthetic resins may be used for each divided body.
[0014]
The thickness of the hollow molded body 2 of the present invention, that is, the thickness of each of the divided bodies 3 and 4 is 0.2 to 7 mm . When the composite molded body 1 is formed using the hollow molded body 2 having a thickness of less than 0.2 mm, when the hollow molded body 2 and the foam molded body 6 are not in direct contact with each other, there is a hollow portion. There is a possibility that the rigidity of the portion of the composite molded body 1 corresponding to the above becomes too small. On the other hand, when the thickness exceeds 7 mm, the weight of the composite molded body 1 becomes too large, which is not preferable.
[0015]
In addition, there is no restriction | limiting in the shape of the composite molded object 1 of this invention, For example, various shapes according to uses, such as plate shape, box shape, rod shape, column shape, are employable.
[0016]
The bonding portion 5 is preferably made of a synthetic resin capable of bonding the divided bodies to each other from the viewpoint that the workability and cost when bonding the divided bodies are low. At this time, as a method of bonding, a method of bonding using an adhesive, sealing bonding, flat butt bonding, knitting bonding, metal clasp, or the like may be employed. When the bonding portion 5 is made of a synthetic resin, it is desirable to use the same resin as the resin used for the divided bodies, but a different resin can be used as long as the divided bodies can be bonded to each other.
[0017]
In this invention, it is preferable to comprise the adhesion part 5 so that the division bodies 3 and 4 and the foaming molding 6 may not be prevented from being separated. As a method for that purpose, as shown in FIG. 2, a structure in which the bonding portion 5 is not in direct contact with the foamed molded body 6, or the thickness of the bonding portion 5 is reduced.
[0018]
In addition, when using the composite molded object 1 of this invention as a container, it is preferable to provide the adhesion part 5 in the outer periphery part of an opening part, as shown in FIG. 1, since the rigidity of a container becomes large.
[0019]
In the composite molded body 1 of the present invention, the foam molded body 6 is inserted into the hollow molded body 2 without adhering. If comprised in this way, the foaming molded object 6 and the hollow molded object 2 can be easily isolate | separated only by cut | disconnecting the composite molded object 1, The synthetic resin which each comprises the foamed molded object 6 and the hollow molded object 2 Recycling becomes easy.
[0020]
However, temporarily fixing the foamed molded body 6 and the hollow molded body 2 to such an extent that they can be easily separated does not fall within the category of adhesion. Temporary fixing is performed in order to improve workability when the foamed molded body 6 is inserted into the hollow molded body 2 and molded as an integral composite molded body, and apparently can be separated easily. It is just a thing to make it adhere. Therefore, only temporarily fixing does not affect workability at the time of recycling.
[0021]
The foam molded body 6 is inserted in a state where at least a part thereof is in close contact with the inner surface of the hollow molded body 2. In the present invention, the foam molded body 6 can be fixed inside the hollow molded body 2 by configuring in this way. From the viewpoint of fixing inside, the foamed molded body 6 needs to be integrally formed, and by being integrally formed, mechanical strength such as 5% strength and compressive strength described later is obtained. be able to.
However, this invention does not restrict | limit and insert the foaming molding 6 currently shape | molded as integral.
[0022]
In addition, as a specific aspect in which at least a part is in close contact with the inner surface of the hollow molded body 2, for example, as shown in FIG. When the side surface inner surface 11 and the side surface inner surface 12 of the hollow molded body are in close contact as shown in b), the side surface inner surface 11 and the side surface inner surface 16 of the hollow molded body are in close contact as shown in FIG. The case where it has adhered to the bottom face inner surface 13 and the bottom face inner surface 14 of the hollow molded body as shown in FIG.
[0023]
In each said aspect, it is preferable that the foaming molding 6 is closely_contact | adhered to the whole surface of the hollow molding 2 like Fig.3 (a). If comprised in this way, the foaming molding 6 will be firmly fixed to the hollow molding 2, the shakiness of the foaming molding 6 can be prevented, and the composite molding which is excellent in rigidity and intensity | strength can be obtained.
[0024]
However, the present invention is not limited to the embodiment described in FIG. 3, and any configuration may be adopted as long as at least a part of the foam molded body 6 is in close contact with the inner surface of the hollow molded body 2. You can also.
[0025]
In order to bring the foamed molded body 6 into close contact with the hollow molded body 2 , the foamed molded body 6 has a 5% compressive strength as described later . Moreover, in order to make the foam molded body 6 adhere to the hollow molded body 2, it is desirable that the foam molded body 6 has physical properties such as compression creep as described later .
[0026]
In the present invention, as shown in FIG. 2, a space 8 may exist between the foam molded body 6 and the inner surface 7 of the hollow molded body 2. However, in the case of the composite molded body 1 that requires high rigidity and high strength, the smaller the space portion, the better.
[0027]
The base resin of the foam molded body 6 can be appropriately selected according to the physical properties required for the composite molded body 1 as a whole, and the base resin of the foam molded body 6 is the base material of the divided bodies 3 and 4. The same resin can be used.
The base resin of the foam molded body 6 can be cross-linked by peroxide or radiation, but is preferably not cross-linked from the viewpoint of recycling.
[0028]
As long as the foamed molded body 6 is a foamed molded body, any type of foamed molded body such as an extrusion foamed molded body and a foamed particle-in-mold molded body can be used regardless of the production method. However, it is preferable to use a foamed particle-in-mold molded body from the viewpoint that the foamed molded body 6 can easily mass-produce a foam molded body having the same dimensions as the inside dimensions of the hollow molded body.
[0029]
In the present invention, the foam molded body 6 is preferably molded in advance. By doing in this way, when shape | molding the composite molded object 1, it can fix to the division bodies 3 and 4 easily.
[0030]
The density of the foam molded body 6 is preferably 0.018 to 0.23 g / cm ³ , although it varies depending on the type of resin constituting the foam molded body. If the density is less than 0.018 g / cm ³ , the compressive strength may be reduced, and the physical properties of the composite molded body may be reduced, or the composite molded body 1 may be depressed due to sink marks or the like. On the other hand, when the density exceeds 0.23 g / cm ³ , the heat insulating property may be deteriorated or the composite molded body may not be reduced in weight.
[0031]
5% compression strength of the foamed molded product 6, in order to contact at least a portion of the foam molded body 6 in the hollow molding 2, and has a 0.1~30kgf / cm ^2. If the compressive strength is less than 0.1 kgf / cm ² , it may be difficult to make the foamed molded body 6 adhere to the inner surface of the hollow molded body 2. On the other hand, when the compressive strength exceeds 30 kgf / cm ² , the compressive strength of the foam molded body 6 becomes too large, and when the foamed molded body 6 is interpolated and the divided bodies 3 and 4 are to be coupled to each other. There is a possibility that the composite molded body 1 cannot be connected to the surface or the composite molded body 1 is deformed after the connection.
In this specification, 5% compressive strength is measured according to the test method of JIS-K6767. After measuring compressive strength to 10%, 5% compressive strength is obtained from the measurement curve. Further, when producing a test specimen for measurement, the entire surface is cut.
[0032]
The amount of strain in the compression creep test of the foamed molded product 6 is preferably 10% or less under the conditions of a load of 0.10 kgf / cm ² and a test period of 100 days. If the amount of strain exceeds 10%, the foamed molded product may not return to its original dimensions while being deformed. If the foamed molded product does not return to the original dimensions, a space is formed between the foamed molded product 6 and the hollow molded product 2, and the foamed molded product 6 is not in close contact with the inner surface of the hollow molded product 2. There is a risk that the rigidity and strength of the molded body may be reduced.
In addition, the compression creep test in this specification shall be performed using a 50 * 50 * 25 mm test piece based on ASTM-C2221-1968.
[0033]
There is no restriction | limiting in the use of the composite molded object of this invention. For example, it can be used for various applications such as containers, heat insulation panels, molds, bumper bumpers, etc., instrument panels, door panels, automobile interior materials such as dashboards and pillars, and buoyancy materials.
[0034]
When the composite molded body of the present invention is used as the container, the resin used is, for example, a hollow molded body made of a polyolefin resin excellent in heat resistance and oil resistance, and a polyolefin resin excellent in compression recovery property and heat resistance. It is preferable to combine with a foamed molded product.
[0035]
When the composite molded body of the present invention is used as a container, the thickness of the hollow molded body is preferably 200 μm to 3 mm from the viewpoint of lightness. Further, the density of the foamed molded product is preferably 0.02 to 0.1 g / cm ³ from the viewpoint of heat insulation.
[0036]
When the composite molded body of the present invention is used as the automobile impact buffer, the resin to be used is, for example, a hollow molded body made of a polypropylene resin or a polycarbonate resin excellent in heat resistance and impact resistance, and an impact absorption property. It is preferable to combine with a foamed molded article made of a polyolefin resin having excellent heat resistance.
[0037]
When the composite molded body of the present invention is used as an automobile shock absorbing material, the thickness of the hollow molded body is preferably 200 μm to 7 mm from the viewpoint of impact resistance. The density of the foamed molded product is preferably 0.025 to 0.3 g / cm ³ from the viewpoint of impact resistance.
[0038]
As an example of the method for producing the composite molded article of the present invention, there is a method of applying the method proposed in Japanese Patent Publication No. 2-38377. The method is a kind of injection molding, and includes a mold provided with a male mold for forming the divided body 3 and a female mold for forming the divided body 4, a female mold corresponding to the male mold, and the female mold. This is a method of using a mold provided with a male mold corresponding to.
[0039]
The procedure of the above method is as follows.
First, after the mold is clamped, the synthetic resin is injected, and the divided bodies 3 and 4 are simultaneously injection-molded and cooled. Next, after the mold is opened, one mold is slid to a position where the divided bodies 3 and 4 remaining in each female mold face each other. Next, the foam molded body 6 molded in advance is inserted into one of the divided bodies remaining in the mold. Next, after the mold is clamped, a synthetic resin is injected to form the bonding portion 5 to form the composite molded body 1. After cooling the bonding part 5, the mold is opened and the composite molded body 1 is taken out.
[0040]
According to the said method, since the composite molded object 1 of this invention can be shape | molded continuously, production efficiency can be improved. In addition, unlike the blow molded hollow molded body, the pin molded hole 1 and the thickness and thickness are small, so that the composite molded body 1 with high quality can be manufactured.
Further, since the foam molded body is inserted after the divided body is molded, any foam molded body having the above physical properties can be used as the core material of the composite molded body, and when recycled, the composite molded The foamed molded product and the hollow molded product can be easily separated by simply cutting the body.
[0041]
In addition, the said method is an example of the method of shape | molding the composite molded object of this invention, Comprising: The manufacturing method of the composite molded object of this invention is not limited to this.
[0042]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[Example 1]
Using a propylene-ethylene random copolymer (melt index 8 g / 10 min, melting point 132 ° C., ethylene content 5.8% by weight) as a base resin for the divided body and the bonded portion, the above-mentioned Japanese Patent Publication No. 2-38377 Using the method described in the publication, two divided bodies constituting the hollow molded body were simultaneously molded using an injection molding apparatus having a mold having the above-described configuration. Next, the mold was opened, and one mold was slid to a position where the divided bodies left in each female mold faced each other. Next, a polypropylene resin expanded particle molded body having a density of 0.02 g / cm ³ (base resin propylene-ethylene random copolymer, ethylene content 7. 4 wt%, melting point 146 ° C., 5% compressive strength 0.4 kgf / cm ² , compression creep strain amount 5%) is inserted into one of the divided bodies remaining in the mold, and then the mold is clamped, The same resin as the base resin of the divided body was injected to mold the bonded portion of the hollow molded body, and the composite molded body of the present invention to be used as a returnable box (opening 330 × 220 mm, depth 90 mm) was molded.
[0043]
[Example 2]
A propylene-ethylene random copolymer (melt index 8 g / 10 min, melting point 132 ° C., ethylene content 5.8% by weight) is used as a base resin for the divided body and the bonded part, and a hollow molded body is used as the foam molded body Polypropylene resin expanded resin molded body having the same dimensions as the inside and a density of 0.18 g / cm ³ (base resin propylene-ethylene random copolymer, ethylene content 7.4% by weight, melting point 146 ° C., 5% compressive strength 20 kgf An automobile bumper (thickness 130 mm, width 180 mm, length 1600 mm) was molded in the same manner as in Example 1 using / cm ² and 3% compression creep strain.
[0044]
【The invention's effect】
Since the synthetic resin composite molded body of the present invention is inserted without bonding the synthetic resin foam molded body to the inner surface of the hollow molded body formed by bonding a plurality of synthetic resin divided bodies to each other, The hollow molded body and the synthetic resin foam molded body can be easily separated simply by cutting the resin composite. Therefore, it is excellent in workability at the time of recycling, and the cost of recycling can be reduced.
[0045]
In addition, the synthetic resin composite molded body of the present invention can be foam molded even if the foam molded body and the hollow molded body are not adhered to each other by adhering the foam molded body and the opposed inner surfaces of the hollow molded body. The body can be firmly fixed to the hollow molded body. Therefore, the foamed molded product does not rattle inside the synthetic resin composite molded product.
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view showing an example of a synthetic resin composite molded article of the present invention.
FIG. 2 is a longitudinal sectional view showing an example of a synthetic resin composite molded body of the present invention.
FIG. 3 (a) is an explanatory view showing an embodiment in which at least a part of the foam molded article is in close contact with the inner surface of the hollow molded article. FIG.3 (b) is explanatory drawing which shows the one aspect | mode in which at least one part of a foaming molding is closely_contact | adhered to the inner surface of a hollow molding. FIG.3 (c) is explanatory drawing which shows the one aspect | mode in which at least one part of a foaming molding is closely_contact | adhered to the inner surface of a hollow molding. FIG.3 (d) is explanatory drawing which shows the one aspect | mode in which at least one part of a foaming molding is closely_contact | adhered to the inner surface of a hollow molding.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Synthetic resin composite molded body 2 Hollow molded body 3 Divided body 4 Divided body 5 Adhesive part 6 Synthetic resin foam molded body 7 The inner surface of the hollow molded body to which the synthetic resin foam molded body is adhered

Claims (1)

Synthetic resin foam molded article having 5% compressive strength of 0.1 to 30 kgf / cm ^{2 on} the inner surface of a hollow molded article having a thickness of 0.2 to 7 mm formed by bonding a plurality of molded divided bodies made of synthetic resin to each other Is inserted without adhering, and at least a part of the synthetic resin foam molded body is in close contact with the inner surface of the hollow molded body, so that the foam molded body is fixed. body.

Images