JPH085495B2 - Container with lid for sealing cooked food - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container with a lid for sealing cooked food that is reheated and eaten.

2. Description of the Related Art Conventionally, retort foods that have been completely sterilized by putting cooked foods such as curry and stew in a plastic bag such as polyethylene, sealing and sterilizing by heating in a retort are well known. This retort food is reheated in hot water in a bag just before being served on the table.

By the way, some cooked foods, such as gratin and hamburger, need to be heated to the extent of scratching the surface during reheating. Since such foods must be heated to a high temperature of about 250 ° C in an electric oven or oven toaster, plastic bags such as those used for retort foods can withstand the boiling water temperature even if they withstand the above high temperatures. It does not have heat resistance. Therefore, conventionally, gratin, hamburger, etc. have been placed in a metal container such as aluminum. However, since it cannot be sealed like a plastic bag, it cannot be sterilized by retort, and it must be frozen for long-term storage. Frozen foods in this way must be kept frozen during the product distribution process and after purchase, and must be thawed before eating, and also have the irritating effect that tastes worse than retort foods. is there.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The object of the present invention is to retort sterilize by sealing without cooking, even in cooked food that requires high-temperature reheating,
Moreover, it is an object of the present invention to provide a container with a lid for sealing cooked foods, which can always ensure reliable thermal adhesiveness between the container and the lid and is easy to open.

Means for Solving the Problems The container with a lid for sealing cooked food according to the present invention comprises an aluminum foil container with a flange and a lid for sealing the container in order to achieve the above-mentioned object. And on the upper surface of the flange, form a synthetic resin coating layer composed of a composition containing an epoxy resin and a polypropylene resin modified with an unsaturated carboxylic acid or an acid anhydride thereof as main components and containing polyisocyanate as a curing agent for the epoxy resin. And a polypropylene resin modified with an unsaturated carboxylic acid or its acid anhydride on the lower surface of the lid,
A synthetic resin coating layer made of a mixture of one or more resins selected from linear copolymerized polyester resins, acrylic resins and styrene copolymerized resins is formed.

 In this specification, parts are based on weight.

The thickness of the aluminum foil is preferably 40 to 150 μm. Four
If it is less than 0 μm, the strength is insufficient, and if it exceeds 150 μm, it becomes difficult to mold and the cost becomes high.

Specific examples of the epoxy resin include a reaction product of epichlorohydrin and a polyhydric phenol such as bisphenol A. Polyisocyanate is used as a curing agent for the epoxy resin, and specific examples thereof include xylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or Examples thereof include adducts thereof, block type isocyanates, and polymers thereof.

The compounding ratio of the epoxy resin and the polypropylene resin modified with unsaturated carboxylic acid or its acid anhydride is preferably 30 to 90 parts in the former case and 5 to 50 parts in the latter case. Epoxy resin
If it is less than 30 parts, the synthetic resin coating layer will melt when reheated due to high temperature, and if it exceeds 90 parts, the thermal adhesiveness will be insufficient,
On the other hand, if the amount of the modified polyolefin is less than 5 parts, the thermal adhesiveness will be insufficient and the adhesion of the container will be impaired, and if it exceeds 50 parts, the heat resistance will be problematic.

The polypropylene resin modified with an unsaturated carboxylic acid or an acid anhydride thereof is a polypropylene resin graft-copolymerized with maleic anhydride, and maleic anhydride is 0.05% from the viewpoint of adhesiveness to aluminum.
Those containing from 5 to 5 parts are preferable.

A composition containing an epoxy resin and a polypropylene resin modified with an unsaturated carboxylic acid or its acid anhydride as a main component, and containing polyisocyanate as a curing agent for the epoxy resin is a solvent such as cellosolve acetate, cellosolve, methyl ethyl ketone, and toluene. As paint,
By coating the aluminum foil, a synthetic resin coating layer on the container side is formed.

It is preferable to add 0.1 to 5 parts of the coupling agent in order to increase the adhesion between the aluminum foil and the synthetic resin coating layer so as not to peel off during deep drawing.

The synthetic resin coating layer on the lid side, polypropylene resin 50 ~ modified with unsaturated carboxylic acid or its acid anhydride
It is preferable to use a mixture of 95 parts and 50 to 5 parts of one or more of linear copolymer polyester resin, acrylic resin and styrene copolymer resin. If the amount of the modified polyolefin resin is less than 50 parts, the thermal adhesive strength is not sufficient, and if it exceeds 95 parts, the thermal adhesive strength becomes too strong, whereas if the amount of the linear copolyester resin is less than 5 parts, the thermal adhesive strength is too strong.
This is because if it exceeds 50 parts, the thermal adhesiveness becomes insufficient. To stabilize the adhesive strength, 1 to 10 parts of a phenol resin and 0.1 to 5 parts of a coupling agent may be further added.

Since some foods contain salt that easily corrodes aluminum, acidic seasonings or spices, it is preferable to interpose a zirconium-containing synthetic resin underlayer between the aluminum foil and the synthetic resin coating layer. .

Effect According to the present invention, since the container is made of aluminum foil, it has heat resistance to high temperatures when heated using an electric oven or an oven toaster.

Further, a synthetic resin composed of a composition mainly composed of an epoxy resin on the entire inner surface of the container body and the upper surface of the flange and a polypropylene resin modified with an unsaturated carboxylic acid or an acid anhydride thereof and containing polyisocyanate as a curing agent for the epoxy resin. Since the coating layer is formed, the container filled with the cooked food can be sealed by heat-sealing the lid on the flange of the container, and the cooked food can be opened by using an electric oven etc. Even if it is reheated at a high temperature, the synthetic resin coating layer does not become discolored or melt and the aesthetics as a food container is not impaired. Because, on the one hand, the epoxy resin has high heat resistance, and the polyisocyanate improves the heat resistance of the epoxy resin, and on the other hand, the polypropylene resin modified with an unsaturated carboxylic acid or its acid anhydride has excellent thermal adhesion. This is because the synthetic resin coating layer has both heat resistance and thermal adhesiveness because it has heat resistance.

Further, since the polypropylene resin does not have sufficient affinity with aluminum and is not modified as described above, the synthetic resin coating layer is easily peeled off from the aluminum foil, but the unsaturated carboxylic acid or its acid anhydride causes the adhesiveness to increase. Since it is modified so as to improve, there is no problem in this respect.

Synthetic resin coating on the lower surface of the lid with a mixture of a polypropylene resin modified with an unsaturated carboxylic acid or an acid anhydride thereof and any one or more of linear copolymerized polyester resin, acrylic resin and styrene copolymerized resin. Since a layer is formed, there is little variation in the adhesive strength due to the drying temperature when forming the coating layer, and this coating layer is heat-sealed at the peripheral edge of the lid onto the flange of the container, making it easy to open by hand when sealing food. Exhibits a degree of thermal adhesion.

Further, since the synthetic resin coating layer containing the modified polypropylene resin is present on both the container and the lid, the heat-sealing of the container is ensured.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

The container (1) comprises a container body (3) and a flange (4) provided at the upper end of its peripheral wall. This container (1)
Is a composition containing 60 parts of epoxy resin and 30 parts of modified polypropylene resin as main components on one side of aluminum foil (5), and 3 g of polyisocyanate, 5 parts of phenol resin and 2 parts of silane coupling agent. / m ² (solid content conversion) After punching a laminated material having a synthetic resin coating layer (6) formed by coating into a predetermined shape, the synthetic resin coating layer (6) is inside the container body (3). It is a deep-drawing molded product. As the modified polypropylene resin, a maleic anhydride modified polypropylene resin containing 0.8 part of maleic anhydride was used.

On the lower surface of the lid (2), a synthetic resin coating layer made of a composition of 90 parts of maleic anhydride-modified polypropylene resin containing 0.8 part of maleic anhydride and 10 parts of linear copolyester resin is formed. It is made of a laminated material.

The following experiment was conducted on the lid and the container. That is, after 180 g of cooked gratin was put in the container body (3), the lid (2) was covered and the peripheral edge portion was heat-sealed to the flange (4) of the container (1). Next, this container (1) containing gratin was subjected to retort sterilization treatment at 120 ° C. for 30 minutes. Then, the lid (2) was removed, and the container (1) containing gratin was placed in an oven toaster and heated at about 250 ° C. for 15 minutes. As a result, the surface of the gratin had dark brown brown eyes, but the synthetic resin coating layer (6) of the container (1)
No change was observed in the.

EFFECTS OF THE INVENTION According to the cooked food-sealed container with a lid of the present invention, not only can the cooked food requiring high-temperature reheating be sealed and retort sterilized without freezing, but the lid can be a container. Since the heat-adhesiveness is good, a perfect seal is always guaranteed, but the heat-adhesiveness is such that it can be peeled off by hand, and therefore the unsealing is easy.

[Brief description of drawings]

1 (a) is a vertical sectional view of a container showing an embodiment of the present invention, and FIG. 1 (b) is a vertical sectional view of a lid placed on the container of FIG. 1 (a). (1) …… Container, (2) …… Lid, (3) …… Container body,
(4) ... Flange, (6) (8) ... Synthetic resin coating layer.

Claims (1)

[Claims] 1. An aluminum foil container with a flange (1)
And a lid (2) for sealing the container (1), which covers the entire inner surface of the container body (3) and the upper surface of the flange (4) and is modified with an epoxy resin and an unsaturated carboxylic acid or an anhydride thereof. A synthetic resin coating layer (6) composed of a composition containing a resin as a main component and a polyisocyanate as a curing agent for an epoxy resin is formed, and an unsaturated carboxylic acid or its acid anhydride is formed on the lower surface of the lid (2). Cooked with a synthetic resin coating layer (8) made of a mixture of a polypropylene resin modified with (1) and a linear copolymerized polyester resin, an acrylic resin and a styrene copolymerized resin. Container with lid for food sealing.