EP0023746A1

EP0023746A1 - Process for packaging margarine and suchlike

Info

Publication number: EP0023746A1
Application number: EP80200732A
Authority: EP
Inventors: Winrich Bernhard Hammerschmidt; Wolfgang Dorawa
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1979-07-30
Filing date: 1980-07-30
Publication date: 1981-02-11
Also published as: ATE5577T1; FI802380A; DE3065882D1; FI65960C; DE2930930A1; EP0023746B1; FI65960B

Abstract

A process and apparatus for providing the surface of margarine and similar pasty products with small cavities prior to bringing said surface into contact with smooth packaging material for decreasing the adherence of said packaging material to said surface. Embossing by directing gas jets onto said surface is preferred, although imprinting with a die is possible as well. The apparatus for putting the process into practice comprises means (11) for making small cavities in the surface (4) of the product. Preferred embodiments of said means are a hollow die (11) with a plurality of nozzle-like openings (12) or a die having a plurality of profilings.

Description

The invention relates to a process for packaging margarine and similar products which have the tendency to adhere to the packaging material, as a result of which opening of the packages is made more difficult.
In German Utility Model 79 02 913 it is proposed to decrease considerably the adherence of pasty products to the closure part by providing the closure part, on a side turned towards the products, with a plurality of small, separate cavities. The disadvantage of this solution, however, is that the cavities on the inner side, obtained for example by embossing, stand out more or less clearly on the outer side of the closure part and that with relatively thin packaging material satisfactory embossing often cannot be achieved.
The aim of the invention is therefore to decrease the adherence of the pasty products to the packaging material, also in the case of closure parts which are smooth on their inner side, so that these packages can be opened easily.
It has now been found that, at least with certain packages where the surface of the product is essentially smooth and relatively firm, the cavities which reduce adherence and in which small air cushions are enclosed can also be made in the surface of the product.
In order to solve the above-mentioned problem, when margarine and similar products are being packaged, before the closure parts are laid against the surface of the portion placed in the container, provision is made for a pattern of small cavities being made in this surface and then a closure part with a smooth inner side is pressed against the edges of the surface surrounding the cavities.
The cavities have an open area of 0.5 mm² to 20 mm², preferably 2 2 of 2 mm² to 6.5 mm², measured approximately in the plane of the surrounding edges, and a depth of 0.4 to 2.5 mm. They are made in the surface of the product, before the lid is put on, by embossing or by jets of gas, e.g. air, directed against the surface. By placing the lid on the edges of the cavities, each of the cavities filled with air or inert gas is sealed off from the neighbouring cavities. When this is done a monitored small amount of air or inert gas is enclosed in each cavity in the surface of the product. In the closed packages the cavities are not connected with each other. On the contrary, each cavity contains a small air cushion with a very slight excess pressure caused by pressing of the closure part against the edges of the cavities. If the cavities are obtained by blowing air against the surface, in that case they form little craters the edges of which are not entirely regular but, as a result of the closure part being pressed down, are brought into a plane with those of the neighbouring cavities, each cavity then being sealed off. Through the use of an embossing tool, cavities of any given cross-section can be obtained, e.g. in the form of truncated pyramids.
If necessary, before the cavities are made, the product can be given a substantially smooth surface, for example by a press-on tool, and/or e.g. its surface be solidified to such an extent by cooling that the cavities can be made and for the greater part will last.
The process is particularly suitable for the packaging of pre-formed portions of margarine of somewhat firmer consistency in erected folding boxes of cardboard material which are to be closed with a lid. However, it can also be applied with beakers or trays which are closed with a plastic lid having a smooth inner side. Finally, the process can also be applied to one or more surfaces of a pre-formed portion which is enclosed by a wrapper.
The invention relates to the apparatus for carrying out the process, which is distinguished from the known apparatuses e.g. for introducing the product into the package and for closing the package in that it has in addition a device for making the small cavities in the surface of the product, against which a closure part is pressed down.
This device for making the cavities can be an appropriately profiled die. A hollow die with a great number of nozzle-like openings is preferred. Jets of air or gas are blown intermittently against the surface of the product. The die can be heatable on its side that is turned towards the product and can be provided with a special coating which, for example, hinders adherence of the product to the die. The use of heated gas for the blowing is possible, but local melting of the product by the jets of air should be avoided. Instead of a die, an appropriately structured roller can be used, under which the unclosed, filled package is transported continuously.
Embodimentsof the invention will now be described with reference to the attached schematic drawings.

Fig. 1 shows cross-section of a filled, unclosed package and a hollow die with openings for blowing through the air;
Fig. 2 is as Fig. 1, but while air is being blown through;
Fig. 3 is a cross-section of the closed package;
Fig. 4 to 6 show magnified sections of a package before and after the cavities have been made and after the lid has been pressed on;
Fig. 7 shows a cross-section of an embossing die.

A portion of margarine 1 is placed in a folding box 2, which is to be closed by a lid 3, the lid 3 being pressed down against the surface 4 of the portion and partly overlapping the front side 5 of the folding box 2. Such a package is difficult to open if adherence of the surface 4 and the lid 3 is not reduced.
A hollow die 11 with a plurality of small, nozzle-like openings 12 in the side turned towards the surface 4 of the margarine is moved towards the filled, unclosed package (Fig. 1). When the die 11 is almost touching the suface 4, air or a suitable gas is intermittently introduced via a gas supply, which air or gas spreads itself in the hollow space 14 of the die 11 over the openings 12 and creates a small, crater-like cavity 6 under each opening 12 (Fig. 2). Thereafter the package is closed, with the inner side of the lid 3 lying on the surface 4, and, as a result of the lid 3 being pressed against the surface 4 on to the edges 7 of the cavities 6, in each cavity 6 an air cushion of a size determined by the volume of the cavity 6 is enclosed, which is isolated with respect to the neighbouring air cushions (Fig. 3).
Fig. 4 shows a cross-section of a part of a package with enclosed product of which the surface 4 is substantially smooth. Fig. 5 shows the cavities 6 made by blowing, which have edges 7 pressed upwards to some extent in a surface 4. In Fig. 6 the lid has been put on and pressed down, the edges 7 being brought into a plane and the separate cavities being sealed off with respect to each other.
Fig. 7 shows a die 21 which is profiled on its under-side with a plurality of pins or similar projections which have the form of a pyramid or a truncated cone and, for example, are staggered. The die 21 is pressed partly into a surface of a product and hereby embosses a pattern of many tiny cups or suchlike, corresponding to its profiling, which, however, are likewise independent of each other.
The sum of all cross-sectional areas of the cavities, measured in the plane of the surface of the product or of the edges surrounding the cavities, must be at least approximately 10% of the total surface area of the product. The maximum of the sum of the cross-sectional areas depends on the size of the separate cavities and on the total surface area as well as on the firmness of the product.

Claims

1. A process for packaging margarine and similar products in containers which are closed by closure parts which are in contact with the product, characterized in that, before the closure parts are placed on the surface of the portion inserted in the container, a pattern of small cavities is made in this surface and subsequently a closure part with a smooth inner side is pressed down against the edges of the surface surrounding the cavities.

2. A process according to claim 1, characterized in that 2 2 cavities with an open area of 0.5 mm² to 20 mm², preferably of 2 mm² to 6.5 mm², measured approximately in the plane of the surrounding edges, and a depth of 0.4 to 2.5 mm are made in the surface of the product before the lid is put on.

3. A process according to claim 1 or 2, characterized in that each cavity is made by blowing a jet of air or gas against the surface of the product.

4. A process according to claim 1 or 2, characterized in that the cavities are made by embossing.

5. A process according to any one of the claims 1 to 4, characterized in that a monitored amount of air or an inert gas is enclosed in the cavities in the surface of the product by putting on the lid.

6. A process according to any one of the claims 1 to 5, characterized in that by putting the lid on the edges of the cavities each of the cavities filled with air or an inert gas is sealed off from the neighbouring cavities.

7. An apparatus for carrying out the process according to any one of the claims 1 to 6 for packaging margarine and similar products, consisting of devices for introducing the product into the package and other devices for closing the package, in which the closure parts are pressed down against the surface of the product, characterized in that it has a device (11, 21) for making small cavities (6) in the surface (4) of the product, against which a closure part (3) is pressed down.

8. An apparatus according to claim 7, characterized in that the device for making the cavities (6) is a hollow die (11) with a plurality of nozzle-like openings (12) for intermittent blowing of jets of air or gas against the surface (4) of the product.

9. An apparatus according to claim 7, characterized in that the device for making the cavities (6) is a die (21) that is provided with a plurality of profilings (22) corresponding with the cavities to be made.

10. An apparatus according to claim 8 or 9, characterized in that the die (11,21) can be heated on its side that is turned towards the product.

11, An apparatus according to claim 8 or 9, characterized in that the die (11,21) is provided with an anti-adhesive coating on its side that is turned towards the product.