Pot lid

The invention relates to a crucible lid which consists of a carrier material which has a printed layer on its facing side and a rough surface coating with a roughening depth in the range of 1 to 100 µm on its facing side.

BACKGROUND OF THE INVENTION

Crucible lids of this kind are used, for example, as lids for yogurt cups or as bottle neck labels. To mark the goods, printing is made on the crucible lids on the side facing away from the packaged goods. It is further known that a coating of heat-sealable varnish is applied to the side facing the packaged goods, for example in the manufacture of lids for yogurt cups. The use of this heat-sealable lacquer results in an airtight and peelable joint between the yogurt crucible and the lid.

To produce these crucible lids, a carrier material, such as aluminum foil, is used in the form of rolls. This carrier material is continuously coated with the hot-melt lacquer on the side facing the packaged goods and is printed on the side facing away from the packaged goods. Correspondingly shaped stamping tools are used to match the shape of the crucible lids to the shape of the packaged goods. After punching, a column of crucible lids is obtained, for example a crucible lid for yoghurt crucibles. Since these crucible lids have both sides smooth, there may be problems when removing the individual crucible lids from this column. The crucible lids adhere to each other so strongly that two or more crucible lids are often removed simultaneously.

In order to avoid this undesirable phenomenon, the surface is roughened by punching before embossing the printed laminate. This produces coarse surface films which can be easily removed from the stack or column because the air enclosed between the roughening projections prevents the films from sticking together. However, such a roughening has the disadvantage that the printing is damaged or even destroyed.

According to document EP 089 746 (A2), the plastic material for the production of toothpaste tubes is fed immediately after its production to a cooling roller which at the same time acts as an embossing roller. The resulting punching of the surface of the plastic material greatly facilitates the subsequent removal of the plastic material blanks from the stack. Instead of stamping, surface roughening can also be achieved by the addition of anti-blocking agents, as described in R. Gachter and H. Müller, Taschenbuch der Kunststoff-Additive, 2nd edition, Carl Hauser Verlag, München-Wien, 1983, p. 346.

The object of the invention is therefore to eliminate this drawback and at the same time to find the design of the crucible lids which will be easy to handle.

The essence of the technical solution

This problem is solved and the described lack of known crucible lids of this kind largely removes the crucible lid, which consists of a carrier material which has a printed layer on its side facing away from the wrapped goods and is coated with a coarse coating on its side facing the wrapped goods. a surface with a roughening depth in the range of 1 to 100 µm, according to the present invention, The coarse surface coating on the carrier material is formed by geometrically arranged spacers which are fusible at elevated temperature.

The geometrically arranged spacers can also be formed on the side facing away from the packaged goods.

-1 CZ 14534 Ul

Said spacers preferably have a height in the range of 4 to 15 µm.

It is also possible that the rough surface coating additionally comprises a granular filler.

The carrier material of the crucible lid may be aluminum, paper or plastic.

The plastic of the carrier material is preferably based on polypropylene, polyethylene, polyamide or polyethylene terephthalate.

The carrier material of the subject crucible lid may also be laminated with the following combination of materials away from the packaged goods: aluminum / aluminum, aluminum / plastic, plastic / aluminum, plastic / plastic, aluminum / paper, paper / aluminum, paper / paper.

In addition, it may be advantageous to provide an additional, temperature-meltable, auxiliary layer between the carrier material and the coating with the coarse, high-temperature-fusible surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The essence of the invention is further elucidated on the basis of examples of its implementation, which are described on the basis of the attached drawings, which show:

- in FIG. 1, a section through a crucible lid with a coating whose rough surface is achieved by the addition of a granular filler,

- FIG. 2 shows a cross-section through a crucible lid with a coating whose rough surface is achieved by an intermediate layer with spacer elements,

FIG. 3 is a cross-sectional view of a crucible lid with a coating whose rough surface is achieved by the spacers formed therein.

Examples of technical solution

The essence of the invention is further elucidated on the basis of FIGS. 1 to 3, wherein FIGS. 2 and 3 show the crucible lids I of the present invention, while FIG. 1 illustrates a crucible lid I known in the art for comparison. 1 to 3, there is shown a crucible lid 1 which essentially consists of a carrier material 5 on which a printed layer 4 is provided on its side facing away from the wrapped goods 2, which is printed. On the side facing the wrapped lid 3 of the crucible lid 1, a rough surface coating 6 is applied.

The thickness of the printed layer 4 is a maximum of 30 µm, while the thickness of the rough surface coating 6 on the side 3 of the crucible lid I facing the packaged goods is a maximum of 120 µm.

The thickness of the carrier material 5 is 5 to 200 pm, in the case of aluminum as carrier material 5, its thickness is in the range 10 to 70 pm, in the case of paper in the range 20 to 150 pm and in the case of plastic in the range 7 to 150 pm.

If the crucible lid I according to the invention is used, for example, as a lid for a yoghurt crucible, the carrier material 5 is preferably made of aluminum with a tensile strength of 60 to 250 N / mm².

The printed layer 4 is produced by applying a printing substrate (not shown) in a manner known per se to the substrate 5 in order to ensure sufficient adhesion between the print and the substrate 5. The substrate 5 is thus provided with a substrate primer for printing, for example, printing by gravure or flexography is now applied. In order to protect this print, it is then provided with a smooth layer of topcoat.

The carrier material 5 is now coated with a rough surface 6 on the side facing the wrapped goods 3.

-2GB 14534 Ul

According to FIG. 1, the roughening of the rough surface coating 6 is achieved by using a granular filler 7. Since the granular filler 7 is deposited, inter alia, on the side 3 of the crucible lid 1 facing the packaged goods, a roughening of at least 1 gm is achieved. Even these relatively small surface roughness values ​​can facilitate the stripping process in the process described in the introduction.

The crucible lid of the present invention, as shown in FIG. 2, is provided with a rough surface coating 6 on its side 3 facing the article to be packaged, consisting of an auxiliary layer 9 of zero or near zero surface roughness. . A further layer is applied to this auxiliary layer 9 by means of a suitably shaped printing cylinder such that a geometric set of spacers 8 is formed on the side 3 of the crucible lid 1 which faces the goods to be packaged. In this case, for example, depressions are formed in the surface of the printing cylinder which correspond to the geometric arrangement and shape of the spacer elements 8. The material used to obtain the spacer elements 8 may additionally comprise a granular filler 7.

Also shown in FIG. 3 is a rough surface coating 6 which comprises a geometric set 15 of spacers 1Ό. The crucible cap 1 of FIG. 3 can be produced in an extremely easy manner, since the rough surface coating 6 is applied directly to the support material 5 by means of a suitably shaped printing cylinder and the spacers 10 are already formed in this process. The printing cylinder is shaped such that a coating thickness 6 in the range of 1 to gm can be achieved, and in the geometric system of spacers 10, a coating thickness 6 in the range 4 to 100 gm is achieved by corresponding depressions 20 in the surface of the printing cylinder.

Industrial Applicability?

The crucible cap I according to this invention is particularly suitable for yoghurt cups. In this application, the rough surface coating 6 is additionally to be provided as a thermofusible layer so as to form an airtight but peelable connection between the lid 25 and the lid.