JPH02206543A - Sealing container for cooked feed - Google Patents

Abstract

PURPOSE:To enable retorting not requiring refrigeration by placing a cooked food needing reheating at a high temperature in an aluminum foil container coated with a synthetic resin, sealing off the container. CONSTITUTION:A container 1 comprises a main body 2 and a flange 3 provided at the upper end of the peripheral wall of the main body 2. A laminate material comprising a synthetic resin coat layer 5 comprising 30-90 parts of an epoxy resin, 5-50 parts of a polypropylene resin modified by an unsaturated carboxylic acid or anhydride thereof, 1-5 parts of a polyisocyanate resin and 0.1-5 parts of a silane coupling agent on one side of an aluminum foil 40-150mum in thickness, is die cut to a predetermined shape, and the resultant blank is deep drawn so that the coat layer 5 is located on the inside of the main body 2 of the container. A cover 6 comprises a laminate material obtained by laminating a 70mum thick aluminum foil 7 with a 50mum thick unstretched polypropylene film 8 serving as a heat sealing material.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a container for sealing cooked food that is to be reheated and eaten.

BACKGROUND ART Conventionally, retort foods have been well known in which cooked foods such as curry stew are placed in a plastic bag such as polyethylene, sealed, and heated and sterilized in a retort to make it completely sterile. This retort food is reheated in the bag in boiling water immediately before being served at the dining table.

By the way, among cooked foods, there are some foods such as gratin and hamburgers that need to be heated to the extent that the surface is slightly browned when reheating. Such foods must be heated to a high temperature of around 250°C in an electric oven or toaster oven, so even if plastic bags such as those used for retort food can withstand the temperature of boiling water, It does not have heat resistance against. For this reason, gratin, hamburgers, etc. have traditionally been placed in metal containers such as aluminum. However, since it cannot be sealed like a plastic bag, retort sterilization cannot be performed, and the product has no choice but to be frozen for long-term storage. Foods frozen in this way must be kept frozen during the product distribution process and even after purchase, and must be thawed before consumption.Furthermore, they tend to taste worse than retort foods. be.

Therefore, the present applicant first proposed a sealed container for cooked food that can be sealed and retort sterilized without freezing even if the cooked food requires high-temperature reheating (Utility Application No. 61-1).
No. 88944).

This proposed container is an aluminum foil container with a flange, and a synthetic resin coating layer made of epoxy resin and polypropylene resin modified with an unsaturated carboxylic acid or its acid anhydride is formed over the entire inner surface of the container body and the top surface of the flange. It is something that is given.

Problems to be Solved by the Invention Flanged aluminum foil containers are formed by deep drawing, but if they have a synthetic resin coating layer as described above, there is a risk that this will peel off during forming. It shouldn't be.

The same thing can also be said during heat sterilization using a retort.

Although there is no problem with the above-mentioned points in the proposed containers, there are some variations in the adhesion between the aluminum foil and the synthetic resin coating layer and the water vapor resistance.

An object of the present invention is to provide a sealed container for cooked food that can be sealed and retort sterilized without freezing even if the cooked food requires high-temperature reheating, and that has improvements in the above points. be.

Means for Solving the Problems In order to achieve the above object, the cooked food sealing container according to the present invention is a flange-equipped aluminum foil container, which includes:
Synthetic resin coating consisting of 30 to 90 parts of epoxy resin, 5 to 50 parts of polypropylene resin modified with unsaturated carboxylic acid or its acid anhydride, 1 to 5 parts of polyisocyanate resin, and 0.1 to 5 parts of silane coupling agent. It is made up of layers.

In this specification, parts are by weight.

The thickness of the aluminum foil is preferably 40 to 15oJ111. If it is less than 40M, the strength is insufficient;
This is because if it exceeds this, it becomes difficult to mold and increases the cost.

Specific examples of epoxy resins include reaction products of epichlorohydrin and polyhydric phenols such as bisphenol A. As a curing agent for epoxy resin, polyisocyanate that does not generate toxic formalin is preferable, and specific examples thereof include xylene diisocyanate, 2
゜4- or 2.6-) lylene diisocyanate, 4.
Examples include 4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, adducts thereof, block incyanates, and polymers thereof.

In order to increase the curing speed of the epoxy resin, 1 to 10 parts of a thermosetting resin such as a phenol resin, an acrylic modified epoxy resin, an acrylic modified styrene resin, an alkyd resin, or a polyvinyl butyral resin may be added. In particular, it is most effective to add 1 to 10 parts of phenolic resin.

The polypropylene resin modified with an unsaturated carboxylic acid or its acid anhydride is a polypropylene resin graft copolymerized with maleic anhydride, and from the viewpoint of adhesion to aluminum, which will be described later, maleic anhydride is 0. Preferably, it contains .05 to 5 parts.

Among coupling agents, silane coupling agents are particularly preferred.

A composition of an epoxy resin, a polypropylene resin modified with an unsaturated carboxylic acid or its acid anhydride, a polyisocyanate resin, and a silane coupling agent is made into a paint using cellosolve acetate, cellosolve, methyl ethyl ketone, toluene, etc. as a solvent. A synthetic resin coating layer is formed by coating the foil.

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

According to this invention, since the container is made of aluminum foil, it is heat resistant to high temperatures when used in an electric oven or toaster oven, and a synthetic resin coating layer is formed on one side of the flat aluminum foil. This can then be formed into a container by deep drawing.

In addition, a synthetic resin coating layer containing 30 to 90 parts of epoxy resin and 5 to 50 parts of polypropylene resin modified with unsaturated carboxylic acid or its acid anhydride is formed on the entire inner surface of the container body and the upper surface of the flange. By heat-sealing the lid to the flange of the container, it is possible to seal the container filled with cooked food, and even if the container is opened and the cooked food is reheated at high temperature in an electric oven, etc. The resin coating layer does not discolor or melt and does not impair the beauty of the food container. This is because epoxy resin has high heat resistance, and polypropylene resin modified with unsaturated carboxylic acid or its acid anhydride has excellent heat adhesive properties, so the synthetic resin coating layer has both of these properties. This is because it has both. If the amount of epoxy resin is less than 30 parts, the synthetic resin coating layer will melt upon reheating at high temperatures, and if it exceeds 90 parts, the thermal adhesion will be insufficient. On the other hand, if the modified polypropylene resin is less than 5 parts, the thermal adhesion will be insufficient and the sealing properties of the container will be impaired.
If the amount exceeds 50 parts, a problem arises in heat resistance, but in the synthetic resin coating layer of the present invention, the former is in the range of 30 to 90 parts and the latter is in the range of 5 to 50 parts, so the above problem does not occur. Among these ranges, the former is 60 to 90 copies, and the latter is 10 copies.
Particularly preferably 30 parts.

In addition, since polypropylene resin does not have sufficient affinity for aluminum, the synthetic resin coating layer will easily peel off from the aluminum foil unless it is modified as described above. Since it has been modified to improve the quality, there is no problem in this respect.

Further, the addition of 1 to 5 parts of polyisocyanate resin as a curing agent for the epoxy resin does not generate formalin when heated at high temperatures, and is therefore suitable for the use of this invention. Other curing agents for epoxy resins include formaldehyde-modified resins such as melamine resins, urea resins, and benzoguanamine resins, but these are not preferred because they generate formalin when heated at high temperatures.

30 to 90 parts of epoxy resin, 5 parts of modified polypropylene resin
The synthetic resin coating layer consisting of ~50 parts of polyisocyanate resin and 1 to 5 parts of polyisocyanate resin not only has high heat resistance and excellent thermal adhesion, but also has good moldability. Addition of 0.1 to 5 parts of ring agent helps improve moldability. The silane coupling agent improves the adhesion between the aluminum foil and the synthetic resin coating layer, but if it is less than 0.1 part, it has no effect, and if it is added in excess of 5 parts, the effect is almost the same. Other coupling agents include titanate-based coupling agents and zircoaluminum-based coupling agents, but they are not only ineffective, but also partially gel, so their addition is not preferred.

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

The container (1) consists of a container body (2) and a flange (3) provided at the upper end of its peripheral wall. As shown in Figure 2, this container (1) consists of 60 parts of epoxy resin, polypropylene modified with an unsaturated carboxylic acid or its acid anhydride, and 60 parts of epoxy resin on one side of aluminum foil (4) with a thickness of 120p. Laminated layer having a synthetic resin coating layer (5) formed by applying a composition consisting of 30 parts of resin, 3 parts of polyisocyanate resin, 5 parts of phenol resin, and 2 parts of silane coupling agent (4 g/rdC solid content equivalent) After punching out the material into a predetermined shape, the synthetic resin coating layer (5) is deep drawn so that it is on the inside of the container body (2).

The lid (B) is 70/1171 thick! Aluminum foil (
It consists of a laminated material in which an unstretched polypropylene film (8) with a thickness of 50/ff is laminated to 7) as a heat sealing material.

The following experiment was conducted on the container (1). In other words, 180g of cooked gratin is placed in the container body (2).
After filling, cover the lid (6) and close the periphery to the container (1).
The flange (3) was heat sealed. Next, this container containing gratin (1) was subjected to retort sterilization treatment at 120° C. for 30 minutes.

Thereafter, the lid (6) was removed, and the container containing gratin (1) was placed in a toaster oven and heated at about 250°C for 15 minutes. As a result, the surface of the gratin had dark brown marks, but no change was observed in the synthetic resin coating layer (5) of the container (1).

Effects of the Invention According to the container for sealing cooked foods of the present invention, even cooked foods that require high-temperature reheating can be sealed and sterilized by retort without freezing. It has improved water vapor resistance and adhesion compared to
There is no fear that the aluminum foil and the synthetic resin coating layer will separate during retort sterilization or deep drawing.

[Brief explanation of the drawing]

The drawing is a vertical sectional view of a container and a lid showing an embodiment of the invention. (1)... Container, (2)... Container body, (3)...
-Flange, (5)...Synthetic resin coating layer. Patent applicant Showa Aluminum Co., Ltd. Agent
Einosuke Kishimoto (3 others),,i,-:i,α,
-3'□ Go to 2□・S゛Procedure auxiliary device (method) % formula % 2. Name of the invention Container for sealing cooked food 3 Relationship with the person making the amendment case

Claims (1)

[Claims] In the flanged aluminum foil container (1), the entire inner surface of the container body (2) and the top surface of the flange (3) are covered.
Synthetic resin coating consisting of 30 to 90 parts of epoxy resin, 5 to 50 parts of polypropylene resin modified with unsaturated carboxylic acid or its acid anhydride, 1 to 5 parts of polyisocyanate resin, and 0.1 to 5 parts of silane coupling agent. A sealed container for cooked food, in which a layer (5) is formed.