JP3131746B2 - Molding method of molded lid for heat resistant container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a molded lid used for a heat-resistant container, wherein the lid itself is transparent and the inside of the lid can be visually recognized from the lid.

[0002]

2. Description of the Related Art As the heat-resistant container, for example, a container having a structure compatible with a microwave oven as shown in FIG. 7 has been proposed. The heat-resistant container 21 has a multilayer plastic container main body 23 having a flange portion 24 at an upper end opening formed by thermally deforming a laminated material 22.
The molded lid 1 having a multi-layer structure fitted to the flange portion 24 is mounted for use. The laminated material 22 includes an intermediate layer 22a, an outer layer 22b, and an inner layer 22c.

[0003] The heat-resistant container does not deform even when the food or drink is filled at a high temperature or is heated by a microwave oven. This is a food and drink cup-shaped container having an effect of preventing deterioration of the contents.

On the other hand, as a lid for the above-mentioned heat-resistant container, a flat lid made of aluminum is generally used in many cases, and the contents of the container can be heated in a microwave oven with the lid kept open. It has the advantage of being excellent.

[0005]

However, in the above container, since the flat lid is made of aluminum, there is a problem that the type and form of the filled food cannot be visually recognized from the outside. In addition, many other heat-resistant containers that have been proposed are generally opaque, and there is a problem that the food filled in the container cannot be visually recognized.

An object of the present invention is to solve such a problem. An object of the present invention is to make it possible to visually check the contents in the heat-resistant container, to have excellent heat resistance, etc. It is an object of the present invention to provide a forming method of a forming lid which can be heated by the method.

[0007]

Molding method of the present onset bright heat-resistant container molding lid Means for Solving the Problems], the sealant layer is formed via an adhesive layer on a transparent thermoplastic resin layer composite sheet material from both sides It is characterized in that, after heating, the substrate layer made of a transparent thermoplastic resin is brought into contact with a molding die, evacuated and molded.

[0008] Cross-sectional structure of the molded lid by the molding method of the present invention
Is composed of a base material layer made of a transparent thermoplastic resin, an adhesive layer, and a sealant layer made of a transparent thermoplastic resin. Preferred specific examples of the resin for forming the base material layer include polyethylene terephthalate, polyvinyl chloride, oriented polystyrene, nylon 6, fluorine resin, polyimide, polyvinylidene chloride, biaxially oriented polypropylene, polycarbonate, polyarylate or high-density polyethylene. And the like.

The adhesive for forming the adhesive layer includes:
Hot melt adhesives such as ethylene-vinyl acetate copolymer as suitable for bonding between plastics; vinyl chloride-vinyl acetate copolymer, epoxy resin, polyurethane, chloroprene rubber, nitrile rubber, cyanoacrylate, acrylic resin, An adhesive such as polyethylene can be used.

As the resin for forming the sealant layer, the above-mentioned resin for forming the base material layer can be used, and a material having a low melting point, for example, a resin for hot melt such as an ethylene-low vinyl acetate copolymer, or a low-density polyethylene , Ionomers and the like can also be employed.

[0011] Further, the molded lid according to the molding method of the present invention comprises:
The flange is fixed to the container body (heat-resistant container) by heat fusion.

[0012]

In the molded lid for a heat-resistant container according to the molding method of the present invention, since the base material layer is formed of a transparent thermoplastic resin, the type and form of the food or the like filled in the container can be visually recognized from the outside. be able to. In addition, since the base layer has good heat resistance, chemical resistance, mechanical properties, etc., close the container immediately after filling the container with hot food or drink, or heat the container contents by placing the container in a microwave oven with the cover It is also possible.

In the method for molding a molded lid for a heat-resistant container according to the present invention, the composite sheet material is heated from both sides, and then the substrate layer made of a transparent thermoplastic resin is brought into contact with a molding die and evacuated. Because it is molded, the composite sheet is used during molding
Since the sealant layer of the material does not come into contact, the inconvenience of the resin sticking to the mold does not occur, and the lid having the desired shape can be efficiently molded by a simple process. As a result, no abnormally deformed portion or damaged portion is generated.

[0014]

Reference Example 1 A molded lid (drop lid) 1 fitted to a conventional heat-resistant container 21 shown in FIG. 7 was molded. The overall shape and cross-sectional structure of the molded lid 1 are as shown in FIGS. That is, in FIG. 1, reference numeral 2 denotes a disk portion, and reference numeral 3 denotes an annular flange portion. As shown in FIG. 2, the molded lid 1 includes a base layer 4 made of a transparent polyethylene terephthalate resin, an adhesive layer 5 made of an epoxy resin or a polyethylene resin, and a sealant layer 6 made of polyethylene in this order from the top. Then, as shown by a two-dot chain line in FIG. 7, the molded lid 1 heats and presses the flange 3 to melt the sealant layer and
Is fitted on the inner peripheral surface of the multilayer plastic container main body 23 and the flange 3 is attached to the multilayer plastic container main body 23.
While being fitted to the flange portion 24 of the multi-layer plastic container main body.

As another reference example, instead of the polystyrene constituting the sealant layer 6 in FIG.
A low melting point thermoplastic resin such as a resin for a hot melt adhesive or a low density polyethylene can be used. Further, instead of the fitting lid 1 of the fitting and mounting type, the whole shape is formed into a substantially flat disk shape, and a concave and convex portion for reinforcement is formed in an appropriate place, and the outer peripheral portion is formed of a multilayer plastic container main body 23. May be simply overlapped on the flange portion 24 and heat-sealed.

Embodiment 1 An embodiment of a method for forming a cover according to the present invention will be described with reference to FIGS. After fixing the composite sheet material 1a having the cross-sectional structure of FIG. 2 with the clamps 11, 11, both surfaces of the composite sheet material 1a are heated to a predetermined temperature by opposing nichrome wire heaters 12, 12 to soften them (FIG. ), The nichrome wire heaters 12, 12 are retracted. Next, the forming die 15 provided below the base material layer 4 and provided with the ejector pins 13 and the suction path 14 communicated with a vacuum generation source (not shown) is raised (FIG. 4), 15 is brought into contact with the surface of the base material layer 4 of the composite sheet material 1a, and the forming die 15 is moved to the upper limit while pushing up the clamped composite sheet material 1a (FIG. 5). Next, the forming die 15 is evacuated by the above-mentioned vacuum source to form the composite sheet material 1a in close contact with the forming die 15, and then the vacuum is broken to release the forming lid 1 with the ejector pins 13 (FIG. 6). Then, the mold 15 is lowered.

[0017]

As described above, in the molded lid for a heat-resistant container according to the molding method of the present invention, since the base material layer is made of a transparent thermoplastic resin, The type and form of the product can be visually recognized from the outside, and the base layer is excellent in heat resistance, chemical resistance, chemical stability, mechanical properties, etc., so the container is filled with hot food and drink The contents can be heated immediately after filling with a lid, or the container can be heated in a microwave oven with the lid still in place, and even if filled with alcoholic beverages or juice drinks with a low pH, the molded lid will deteriorate and adversely affect the quality of the contents. No effect. Further shaped lid, since it is intended to fix by heat-sealing the flange portion on the container main body, on a sealed state of the container body content is good, it is possible to open the container by peeled off a formed cap .

A substrate layer made of the above transparent thermoplastic resin
, Polyethylene terephthalate, polyvinyl chloride, rolled
Stretch oriented polystyrene, nylon 6, fluorine resin, poly
Mid, polyvinylidene chloride, biaxially oriented polypropylene,
Polycarbonate, polyarylate or high density polyether
When made of styrene, the base layer is made of a transparent thermoplastic resin that has particularly excellent heat resistance and chemical resistance, making it extremely convenient as a mold lid for containers compatible with microwave ovens. There are advantages that can be used.

Further , the above-mentioned adhesive layer is made of ethylene-vinyl acetate.
Vinyl copolymer, vinyl chloride-vinyl acetate copolymer, epoxy resin
Xylene resin, polyurethane, chloroprene rubber, nitrile
Rubber, cyanoacrylate, acrylic resin or polyether
When using a stell, an adhesive with high adhesive strength between the base material layer and the sealant layer and excellent heat resistance is used. There is no occurrence of peeling between the base material layer and the sealant layer when peeling off from the container body.

The above-mentioned sealant layer is made of a transparent thermoplastic resin.
When formed, the molded lid is formed of a laminate of a base material made of a transparent thermoplastic resin and a sealant layer, so that the molded lid has excellent mechanical strength, heat resistance, and the like.

Further, according to the method of forming a molded lid for a heat-resistant container of the present invention , a molded lid having a desired shape can be molded by a simple apparatus and process, and the composite sheet is excellent in heat resistance . At the time of molding, an abnormally deformed portion or a damaged portion does not occur in the molded lid, and a molded lid suitable for a microwave oven having good appearance and excellent durability can be manufactured. Also, since the base layer made of a transparent thermoplastic resin is evacuated and molded so as to hit the mold, the sealant layer does not come into contact with the mold, so that the resin sticks to the mold. No inconvenience occurs.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a reference example of a molding lid according to a molding method of the present invention.

FIG. 2 is a sectional view showing a layer configuration of the molded lid of FIG.

FIG. 3 is an explanatory view of a heating step of a composite sheet material in an embodiment of the forming lid forming method of the present invention.

FIG. 4 is an explanatory view of a molding die raising step in an embodiment of the molding lid molding method of the present invention.

FIG. 5 is an explanatory view of a mold suction step in the embodiment of the molding lid molding method of the present invention.

FIG. 6 is an explanatory view of a mold release step in an embodiment of the method for forming a cover according to the present invention.

FIG. 7 is a half sectional view showing a conventional example of a heat-resistant container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding lid 2 Disk part 3 Flange part 4 Base layer 5 Adhesive layer 6 Sealant layer 11 Clamp 12 Nichrome wire heater 13 Ejector pin 14 Suction path 15 Mold 21 Heat resistant container 22 Laminated material 23 Multilayer plastic container main body 24 Flange part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Hira 3-8172 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) B65D 77/20 B65D 8/20

Claims (1)

(57) [Claims] 1. After heating a composite sheet material having a sealant layer formed on a transparent thermoplastic resin layer via an adhesive layer from both sides, a base layer made of a transparent thermoplastic resin hits a mold. A method for forming a lid for a heat-resistant container, comprising: