IL39609A - Container made of composite film - Google Patents

Description

CONTAINER MADE OP COMPOSITE FILM - ABSTRACT OF THE DISCLOSURE This invention relates to a container made from a multilayer composite film in which the inner surface of the container bottom and of the container walls is a layer of polyolefin, the outer surface of the container bottom arid the container walls is a synthetic thermoplastic material of high heat resistance , and intermediate the said layers is a layer of a chemical means bonding said layers .

- CONTAINER MADE OF COMPOSITE FILM This invention relates to a container, preferably in the form of a dish or a beaker, which is composed of a three-layer composite film .

The present invention provides a container, in the form of a dish or a beaker made of composite film , in which it is possible to heat material contained therein, especially foodstuffs and precooked meals , particularly in microwave ranges without the container being deformed or destroyed thereby and to keep filled and heat-sterilized dishes storable over a relatively long period of time without deepfreezing .

Dishes made of polyethylene of high density are known for the mentioned purpose but they have the disadvantage that their heat resistance is not sufficient to ensure sufficient dimensional stability at the extremely high temperatures encountered during the heating of the filled dishes , e .g . in microwave ranges at about 200°C .

Furthermore , the high gas permeability of these plastics does not allow storage of sterilized non-frozen precooked meals in contain-, ers closed with lids and consisting of the said plastics .

Containers in the form of beakers or dishes are called "containers" in the following .

The present invention provides a container of a multi-layer composite film in which the inner surface of the container bottom and the container wails' consists .of a layer of polyolefin and the outer surface of the container bottom and the container walls consists of a synthetic thermoplastic material of high heat resistance . Between these layers is a layer of a chemical means effecting the union thereof .

K-2128 The container wall may be bent outwardly in the zone of the container opening in such a way that either an outwardly extending horizontal opening flange is obtained or that, upon further bending of the opening flange , a mouth roll is formed .

Preferred containers have a flange in the zone of the opening so that they may be closed by means of a planar lid by sealing . The sealed lid consists of a composite film of the same layer structure as the film of which the container is made . It may contain an additional aluminium layer but then heating in a microwave range is possible only after removal of the lid . When closing the container opening by sealing a lid thereon, the polyolefin layer thereof and that of the container in the zone of the flange of the container face one another, whereby sealing may be performed in known manner.

The container may be produced in known manner according to the thermoforming process from a multi-layer composite film consisting of a layer of a thermoplastic material of high heat resistance, par-ticuiarly polyamide , preferably polyester, a layer of polyolefin and , between both layers , a layer of a chemical means effecting the union of the first-mentioned layers .

The polyolefin layer of the container may have a thickness in the range from 0. 2 to 0. 7 mm , preferably in the range from 0.4 to 0 .6 mm .

The polyolefin layer consists of polypropylene or polyethylene, preferably of polyethylene of mean density or particularly preferably of polyethylene of high density .

The layer forming the outer surface of the container consists of a synthetic thermoplastic material of sufficient heat resistance .

- « The term " sufficient heat resistance" means that the layer does not lose its dimensional stability in the range of the temperature of the container in use and that the plastic material forming the layer is not thermally degraded .

The temperature in use also means the temperature to which the container is exposed during heating of the material contained therein, i . e . a temperature up to about 200°C .

The outer layer of the container preferably consists of a polyamide, particularly preferably of a polyester.

If the outer layer consists of polyester it has a thickness, in the range of 0 .01 to 0 .03 mm .

The layer of polyester consists particularly preferably of an oriented polyester film of a thickness of 0 .02 mm, preferably of thermo formable non-brittle polyester film of sufficient strength . The inner surface of the polyamide or polyester layer may further have a coating of poly inylidene chloride . The layer between the outer layer and the inner layer and firmly uniting both layers consists of a chemical means which is briefly resistant to heat up to 200°C , i . e . which does not lose its bonding force up to this temperature , does not thermally decompose and also is not sensitive to considerable temperature variations within short periods of time (deep-freezer / microwave range) as regards its bonding capacity . The chemical bonding layer must be insensitive. to moisture . - The chemical bonding layer preferably consists of synthetic polymer material which fulfills the mentioned conditions; the bonding layer is preferably based on polyurethane .

The accompanying drawing illustrates the invention without - section through a dish the side walls of which are bent outwardly in the zone of the opening to form a flange . The illustrated sealed lid with which the dish may be closed consists of a sheet of the same layer structure as that of the multi-layer material forming the dish.

Numeral 1 designates the dish, numeral 2 the outer layer of the dish consisting of polyamide or polyester, numeral 3 the inner layer thereof consisting of polyolefin, and numeral 4 the bonding layer arranged between the two aforementioned layers . Numerals 2a , 3a , and 4a have the same meanings for the lid film as have numerals 2 , 3 , and 4 for the container.

It is a particular advantage that the container can be easily produced in known manner according to the thermoforming process from a planar sheet of composite film of the described layer structure . . i The production of the composite film from which the container may be formed , for example by deep-drawing , is performed by applying the adhesive layer in known manner to the surface of a polyester film by means of a doctor device . The polyester film provided with the adhesive layer is then laminated in known manner to the second plastic film , a film of polyethylene of high density , so that the surface of the latter is adjacent to the adhesive layer. Lamination is performed with the simultaneous application of heat and pressure upon the sheet material, e .g . the films are laid upon one another and passed through , the gap of a pair of heated laminating rollers .

The maximum temperature in the range of the temperature of use of the dish - a temperature up to 200° - which may occur during heating of the filled containers represents a brief temperature action upon the container . - to prepare the precooked or prefried or otherwise prepared food in the containers so that it can be consumed , or to heat it to a temperature whereby the meal can be eaten .

In the case of foodstuffs which, due to their high, dipole moment, are suitable for heating in microwave ranges , i . e . particularly water-containing foodstuffs , such as meat, vegetables , potatoes , and the like , the heating duration is measured in seconds .

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications .

Claims (1)

1. WHAT IS CLAIMED IS A eontainor from a composite film which tho inner surface of tho eoatainor bottom and the container is a layer of polyethylene of the outer of the container bottom and the eoataiaor walls is an oriented polyester and intermediate the said layers a layer of At orney or App cant insufficientOCRQuality