JP4327275B2 - Compact - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molded body suitable for packaging materials that require heat insulation properties, such as food packaging containers, home appliance packaging materials, precision equipment packaging materials, and the like.
[0002]
[Prior art]
Some synthetic resin moldings have a space formed therein by a foamed sheet molding or a double wall structure, and air is sealed in the space for heat insulation.
[0003]
[Problems to be solved by the invention]
In order to obtain a good molded product from the foamed sheet, the amount of gas in the foamed sheet must be controlled, and the curing process after the foamed sheet manufacturing takes more than a week. There are problems such as.
[0004]
In addition, the double-walled synthetic resin molded article has no problem in terms of strength and heat insulation, but the type in which the inner container and the outer container are manufactured and combined in the subsequent process has a complicated manufacturing process. . In addition, two types of synthetic resin sheets are softened by heating, introduced into a male mold and a female mold, and evacuated by both molds. It is difficult to set the molding conditions, and when the container is used as a heating container, the air in the double wall space is heated and expanded, and when the container is deformed and damaged due to loss of escape The dimensional stability of is insufficient.
[0005]
An object of the present invention is to solve the above-mentioned problems, and to provide a molded article having excellent productivity and excellent heat insulation and strength.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the molded article according to claim 1 of the present invention is formed between two resin sheets having a thickness of 0.05 to 2.0 mm made of a single layer or multilayer thermoplastic resin mainly composed of a polyester resin or a polypropylene resin. In addition, a molded sheet formed by heating and softening a laminated sheet having a basis weight of 150 to 1600 g / m ² having a honeycomb structure part that forms a space part by interposing a resin sheet having a honeycomb structure formed thereon and molding with a mold. The molded body maintains a honeycomb structure part that forms a space between the two resin sheets, and the honeycomb structure part of the molded body has an air-filled part in a part of the honeycomb structure part. In addition, a part or all of the space part of the honeycomb structure part other than the air sealing part is structured to communicate with the outside.
In addition, the formed body of claim 2 of the present invention is characterized in that, in the formed body of claim 1, the thickness is 0.3 to 6.0 mm and the thickness of the honeycomb structure portion is less than 2.0 mm. .
The molded body according to claims 1 and 2 is excellent in productivity and heat insulation, has sufficient strength, and when heated, the expanded internal air is discharged to the outside. And is particularly useful as a microwave oven.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a laminated sheet for obtaining a molded article of the present invention. The laminated sheet 1 has a honeycomb structure portion A that forms a space between resin sheets 2 and 3 made of a single layer or multilayer thermoplastic resin.
[0010]
The laminated sheet 1 is formed using, for example, the manufacturing apparatus shown in FIG. First, the resin sheet 4 extruded from the die 10 is guided to the vacuum forming roll 13 through the temperature control rollers 11 and 12, and the hemispherical protrusion 4a is formed on the roll 13 as shown in FIG. They are formed at almost equal intervals. On the other hand, the resin sheet 2 extruded from the die 14 is associated with the resin sheet 4 on the vacuum forming roll 13, and the resin sheets 2 and 4 are fused together through the vacuum forming roll 13 and the backup roll 17. Then, as shown in FIG. 3 (b), the resin sheets 2 and 4 that are superposed and fused together are guided to rollers 15 and 16. On the other hand, the resin sheet 3 extruded from the die 17 is guided between the rollers 15 and 16, and the sheet 3 is caused to associate with the resin sheets 2 and 4 fused to each other so that the protruding portion of the resin sheet 4 is interposed between the rollers 15 and 16. By laminating the resin sheet 3 on the top of 4a, the laminated sheet 1 as shown in FIG. 3C is obtained. In addition, you may adhere each resin sheet with an adhesive agent. And the laminated sheet 1 laminated | stacked in this way is heat-softened, and the molded object (container) 5 as shown, for example in FIG. 4 is obtained with a metal mold | die. However, FIG. 4 shows a half cut view of the container 5.
[0011]
The honeycomb structure A in the present invention means a structure in which a hollow portion is defined between the resin sheets 2 and 3 by partition walls that are installed across the resin sheets 2 and 3, and the shape of the partition walls is shown in FIG. There are other shapes such as a circular shape as shown in FIG. 5, a parallel straight shape as shown in FIG. 5, and a rectangular shape (not shown). The material, thickness, etc. for forming the partition are the same as those of the resin sheets 2 and 3.
In the case where the resin sheets 2 and 3 used in the present invention are single layers, the single-layer sheets include low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, polystyrene, Examples of the base resin include polyvinyl chloride, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and copolymers thereof. Moreover, what mixed 2 or more types of said base resin can also be used as base resin.
[0012]
Further, when the resin sheets 2 and 3 used in the present invention are multi-layers, the multi-layer resin sheets include those obtained by laminating and bonding a plurality of the above single-layer sheets with an adhesive, heat, etc. , Gas barrier resin sheet made of polyvinyl alcohol resin, conductive resin sheet containing carbon, antistatic resin sheet, light-shielding resin sheet, rust-proof resin sheet, etc. .
[0013]
Preferable resin sheets (whether single layer or multilayer) 2, 3 are mainly composed of a polyester resin having excellent heat resistance, or mainly composed of a polypropylene resin, and further 5 to 40 weight of an inorganic filler. There are some which are mainly composed of polypropylene resin with excellent dimensional stability, moldability, rigidity and heat resistance. Examples of the inorganic filler include talc, magnesium carbonate, calcium carbonate, mica, clay, gypsum, silica, kaolin, barium sulfate, calcium sulfate, and aluminum oxide. Here, “mainly” means that it is contained in an amount of 50% by weight or more based on the entire resin of the single layer or multilayer sheet.
[0014]
The thickness of the single-layer and multilayer resin sheets 2 and 3 is 0.05 to 2.0 mm, and may be selected from this range depending on the application. In particular, when the molded article of the present invention is used as a microwave heating container, the thickness is preferably 0.1 to 0.3 mm in terms of lightness, rigidity, and workability. When the thickness is less than 0.05 mm, it is difficult to form a honeycomb structure having a good space at the time of heat molding with a mold, and the strength of the obtained molded body is insufficient. On the other hand, when the thickness exceeds 2.0 mm, the processability at the time of heat forming with a mold is inferior.
[0015]
The laminated sheet 1 for obtaining the molded body of the present invention has a basis weight of 150 to 1600 g / m ² and preferably has a thickness of 0.3 to 6.0 mm. If the thickness is less than 0.3 mm, the molded body may have insufficient rigidity and heat insulation. On the other hand, if the thickness exceeds 6.0 mm, the moldability tends to be inferior. In the present invention, the thickness of the laminated sheet 1 is particularly preferably 0.8 to 2.0 mm. Moreover, the thing whose basic weight is less than 150 g / m < ² > becomes inadequate in the rigidity of a molded object. On the other hand, when the basis weight exceeds 1600 g / m ² , the lightness and heat moldability are insufficient. In this invention, it is preferable that the basic weight of a lamination sheet is 400-800 g / m < ² >.
[0016]
The molded body 5 is obtained by heating and softening the laminated sheet 1 and molding it with a mold, and the mold molding method is not particularly limited. For example, conventional vacuum molding and compressed air have been performed. Molding and free drawing molding using these, straight molding, draw molding, plug and ridge molding, ridge molding, matched molding, reverse draw molding, air slip molding, plug assist molding, plug assist reverse draw molding, and combinations of these Examples include molding.
[0017]
The thickness of the honeycomb structure portion A of the molded body 5 obtained by the above molding is preferably less than 2.0 mm. When this thickness is too thick, not only the moldability is inferior, but also when the molded body 5 is punched after heat molding, the honeycomb structure A is exposed at the peripheral edge of the punched molded body 5. In addition, there is a risk of problems such as poor appearance and breakage when the molded body 5 after punching is covered with a wrap film. If the thickness of the honeycomb structure portion A is less than 2.0 mm, the above-described problems can be reliably prevented. Moreover, the thing of 0.3-6.0 mm of the whole thickness of the molded object 5 is preferable at the surface of rigidity, heat insulation, and an external appearance.
[0018]
Further, when the molded body 5 of the present invention is used particularly as a microwave heating container, as shown in FIG. 3, by forming a structure having an air-sealed part a in a part of the honeycomb structure part A, When the container contents are heated in the range, the air sealing portion a of the honeycomb structure portion A increases in volume due to the volume expansion of the air inside, and the heat insulation can be further enhanced.
[0019]
Furthermore, since part or all of the space portion (portion other than the air sealing portion a) b of the honeycomb structure portion A communicates with the outside, the volume of the air expands due to heating of the honeycomb structure portion A by a microwave oven or the like. Too much does not deform the container greatly.
[0020]
Moreover, FIG. 6 has shown the molded object (container) 6 obtained using the laminated sheet of other embodiment which concerns on this invention. The laminated sheet 7 used in the molded body 6 is formed of a hemispherical protrusion by a vacuum forming roll or the like on a resin sheet 8 made of a single layer or multilayer thermoplastic resin of the same material as the resin sheet 2 shown in FIG. 8a is formed, and a resin sheet 9 made of a single-layer or multi-layer thermoplastic resin of the same material as the resin sheet 3 shown in FIG. The thickness shown as T in FIG. 6 is 0.3 to 2.0 mm and the basis weight is 50 to 1500 g / m ² . The thickness of the resin sheets 8 and 9 is preferably 0.1 to 0.3 mm. And this laminated sheet 7 is heat-softened and the molded object (container) 6 is obtained with a metal mold | die, for example. According to this container 6, especially when holding the microwave-heated container 6 by hand, the part that touches the hand is the air enclosing part a, so that the encapsulated air becomes a heat insulating layer and becomes hot and cannot be held. It is prevented. Moreover, by having an air-filled convex part such as the protrusion 8a, when the container storage part is heated in a microwave oven, the volume of the convex part is increased by the volume expansion of the air inside the convex part, and the heat insulation is further enhanced. Can do.
[0021]
【The invention's effect】
The molded body according to the present invention is excellent in heat insulation and strength, and is excellent in productivity. Further, when the molded body of the present invention is used as a microwave oven container, it is possible to further improve the heat insulating property by having an air-sealed part in a part of the honeycomb structure part. Part or all of the structure communicates with the outside, and the shape retainability is particularly excellent.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a laminated sheet for forming a molded body according to the present invention.
2 is a configuration diagram of an apparatus for forming the laminated sheet shown in FIG. 1. FIG.
3 is a perspective view showing a process of forming the laminated sheet shown in FIG. 1. FIG.
4 is a perspective view of a molded container according to the present invention formed using the laminated sheet shown in FIG. 1 in half.
FIG. 5 is a perspective view showing another embodiment of a laminated sheet for forming a molded body according to the present invention.
FIG. 6 is a partial perspective view showing another embodiment of a molded body according to the present invention.
[Explanation of symbols]
1 Laminated sheet 2, 3, 4 Resin sheet 4a Protrusion 5 Molded body (container)
6 Molded body (container)
7 Laminated sheets 8 and 9 Resin sheet a Air sealing part

Claims (2)

A resin sheet having a honeycomb structure is interposed between two resin sheets having a thickness of 0.05 to 2.0 mm made of a single layer or multilayer thermoplastic resin mainly composed of a polyester resin or a polypropylene resin. a molded body obtained by molding a laminated sheet having a basis weight 150~1600g / m ² having a honeycomb structure forming a space portion in a heating softened allowed mold, the molded article is two the resin sheet A honeycomb structure part forming a space part is maintained, and the honeycomb structure part of the formed body has an air sealing part in a part of the honeycomb structure part, and the honeycomb structure part other than the air sealing part has a space A formed body having a honeycomb structure part, wherein a part or all of the part has a structure communicating with the outside.   The molded body having a honeycomb structure according to claim 1, wherein the molded body has a thickness of 0.3 to 6.0 mm and a thickness of the honeycomb structure is less than 2.0 mm.

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