Method in the manufacture of a packaging laminate, a plant in the manufacture of the packaging laminate, and the thus manufactured packaging laminate

Abstract

A method in the manufacture of a web-shaped packaging laminate (22) comprising a core layer (24) of paper or paperboard, the method including the steps of coating (38) a first side of a material web (40) of paper or paperboard with an outer layer (26) of thermoplastic material, an thereafter forming, with the aid of laser burning (46, 48) on the thus thermo-plastic coated first side of the packaging laminate (22), a perforation line (32) through said thermoplastic layer (26) and said core layer (24). After said coating (38) with the thermoplastic material but before the formation of the perforation line, the packaging laminate (22) is compressed (44, 10) on said first side for the formation of a compression line (30) in which said core layer (24) is compressed, whereafter said perforation line (32) is formed in said compression line (30). The present invention also relates to a plant in the manufacture of the packaging laminate, as well as the thus produced packaging laminate (22).

Description

TECHNICAL FIELD [0001] The present invention relates to a method in the manufacture of a web-shaped packaging laminate comprising a core layer of paper or paperboard, the method including the steps of coating a first side of a material web of paper or paperboard with an outer layer of thermoplastic material, and thereafter, with the aid of laser burning on the thus thermoplastic coated first side of the packaging laminate, forming a perforation line through said thermoplastic layer and said core layer. The present invention also relates to a plant in carrying the method into effect, as well as the packaging laminate produced by means of the method. THE STATE OF THE ART AND PROBLEM [0002] Consumer packages for foods are often manufactured from a flexible packaging material which, by cutting, folding, sealing and filling, has been converted into filled and sealed packaging containers of the desired configuration. The packaging material normally consists of a laminate which includes a ...

AI Technical Summary

Benefits of technology

[0006] According to the present invention, a method and a plant are proposed in the manufacture of a laser-perforated packaging laminate whereby the above-outlined drawbacks are obviated or at least reduced. According to the present invention, the thus manufactured packaging laminate is also proposed which lacks projecting ridges of residual material substantially from its outer surface from the laser perforation, and which preferably displays improved accessibility in the perforation, simultaneously with superior integrity, i.e. slight risk of leakage.

Problems solved by technology

When the packaging laminate is further processed, including processing on rollers or rolling up on magazine reels, these ridges of residual material may cause problems.

When the packaging laminate is rolled up on magazine reels, the ridges build up in the different layers in the magazine reel on one another so that the reel becomes uneven on the outside, which seriously impedes its handling.

Moreover, residual material from each ridge is deposited from the outside of the packaging laminate onto the inside of the next layer of packaging laminate in the reel, which implies an undesirable presence of residual material on the inside of the packaging laminate when this is to be reformed into packaging containers and be filled with their intended contents.

However, this is not desirable, given the problem of dust formation.

In large scale production, large quantities of dust would be created which would have a harmful effect on the working environment and which would need to be taken care of.

Another, more general problem in connection with opening arrangements in the form of perforation lines is to realise a perforation which is easy to open (good accessibility) but which does not incur the risk of leakage in the event of rough handling of the packaging container.

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