DE102023111064A1 - Embossed packaging material for twist packaging and process for its manufacture - Google Patents

Abstract

Cellulose-based packaging film (1) for packaging foodstuffs as twist packaging, wherein this packaging film (1) has a base layer (2) which extends in a longitudinal direction (L), a width direction (B) perpendicular to the longitudinal direction (L) and a thickness direction (D) perpendicular to the longitudinal direction (L) and the width direction (B), and wherein the base layer has a first surface (2a) which extends in the longitudinal direction (L) and the width direction (B) and a second surface (2b) which extends in the longitudinal direction (L) and the width direction (B) and which is opposite the first surface (2a), and wherein the base layer (2) is made of paper and/or cellulose-containing material, characterized in that the base layer (2) has a structure and/or embossing at least in sections, such that a first section (22) of the base layer (2) is offset relative to a second section (24) of the base layer with respect to at least one axis of rotation by at least Can be rotated by 180° in order to form the twist packaging - especially without cracks.

Description

The present invention relates to a packaging material, in particular for packaging foodstuffs. In particular, the invention relates to so-called twist packaging, which is used, for example, to package sweets or the like.

It is known from the state of the art to use paper for such packaging purposes. Papers coated with wax are usually used to make these papers more flexible. In other words, these papers usually have wax coatings. The wax makes the paper more flexible so that it adapts better to the contours of the product and does not tear. Wax usually comes from oil derivatives and is therefore a source of mineral oil contamination. The use of wax is also viewed critically with regard to the recycling process. The wax coating seals the surfaces so that they are watertight, which means that the water in the recycling process can no longer dissolve the fibers, which in turn means that the wax-coated paper can often only be recycled thermally. In addition, recent discussions by the EU Commission have shown that wax coatings on paper should be listed as negative in terms of the recycling cycle.

The present invention is therefore based on the object of providing a paper-based and/or cellulose-containing, twistable packaging material which in particular dispenses with the use of wax components.

This object is achieved according to the invention by the subject matter of the independent patent claims. Advantageous embodiments and further developments are the subject matter of the subclaims.

The invention relates to a cellulose-based packaging material or packaging film for packaging foodstuffs, in particular as twist packaging, wherein this packaging material has a base layer which extends in a longitudinal direction, a width direction perpendicular to the longitudinal direction and a thickness direction perpendicular to the longitudinal direction and the width direction, and wherein the base layer has a first surface which extends in the longitudinal direction and the width direction, and a second surface which extends in the longitudinal direction and the width direction and which is opposite the first surface, and wherein the base layer is made of paper and/or cellulose-containing material.

According to the invention, the base layer has at least in sections a structure and/or embossing such that a first section of the base layer can be rotated by at least 180° relative to a second section of the base layer with respect to at least one axis of rotation in order to form the twist packaging and preferably to form it without cracks.

It should be noted that in this description the terms packaging material and packaging film are used synonymously.

It is therefore proposed within the scope of the invention to dispense with a wax coating in particular and to achieve the necessary softness or flexibility of the material through the structures mentioned. This structure provides a certain flexibility, which enables twisting. The term twisting is understood to mean that a first section of the base layer can be rotated by at least 180° relative to a second section of the base layer with respect to at least one axis of rotation in order to form the twist packaging without damage.

Twist packaging is packaging in which one section of the packaging material is twisted and/or twisted relative to another section of the packaging material.

Preferably, the extension of the packaging material or twist packaging in the thickness direction is significantly smaller than the extension in the longitudinal direction and/or the width direction. Preferably, the extension of the packaging material in the thickness direction is less than 5% of the extension in the width direction, preferably less than 3%, preferably less than 1% and preferably less than 0.5%.

The base layer and/or the material of the base layer preferably has a (particularly maximum) grammage which is between 15 - 70 g/m ² and particularly preferably between 30 - 50 g/m ² . In a further preferred embodiment, the base layer and/or the material of the base layer has a long fiber content of 50 - 100%, preferably 70-100%. In a further preferred embodiment, the base layer and/or the material of the base layer has a filler content of 0 - 30%.

In a preferred embodiment, the packaging material and/or the base layer has an extension in the longitudinal direction that is greater than 1 cm, preferably greater than 2 cm, preferably greater than 3 cm. In a further embodiment In this embodiment, the packing material and/or the base layer has an extension in the longitudinal direction which is less than 30 cm, preferably less than 25 cm, preferably less than 20 cm, preferably less than 15 cm and preferably less than 10 cm.

In a further preferred embodiment, the packaging material and/or the base layer has an extension in the width direction which is greater than 2 cm, preferably greater than 3 cm, preferably greater than 4 cm.

In a further advantageous embodiment, the packaging material has an extension in the width direction which is less than 40 cm, preferably less than 35 cm, preferably less than 30 cm, preferably less than 25 cm, preferably less than 20 cm and particularly preferably less than 15 cm.

In a further preferred embodiment, the packaging material has an extension in the thickness direction that is greater than 15 µm, preferably greater than 20 µm, particularly preferably greater than 25 µm and especially preferably greater than 30 µm. This information relates in particular to the already embossed paper and/or the already embossed base layer.

Particularly preferably, the packaging material has an extension in the thickness direction that is less than 120 µm, preferably less than 100 µm and particularly preferably less than 80 µm. These extensions are measured in particular according to DIN EN ISO 534.

In a further advantageous embodiment, the packaging material has a modulus of elasticity which in MD (machine direction) is between 3000 MPa and 10,000 MPa, preferably between 4000 MPa and 6000 MPa, and in TD (transverse direction) is between 1000 MPa and 6000 MPa, preferably between 1500 MPa and 3000 MPa. The modulus of elasticity is therefore preferably reduced by the embossing. The modulus of elasticity in MD and/or TD is preferably reduced by at least 20%, preferably by at least 40% and preferably by at least 70% and preferably by 90% compared to an unembossed version. In a preferred embodiment, the modulus of elasticity is reduced by a maximum of 90%. The values were determined analogously to DIN EN ISO 1924-2.

In a further advantageous embodiment, the packaging material has a breaking load elongation which in MD is between 1.5% and 3.0%, preferably between 1.8% and 2.2% and in TD is between 6.0% and 9.0%, preferably between 6.5% and 8.0%. The breaking load elongation is therefore preferably increased by the embossing.

Preferably, the breaking load elongation in MD and/or TD is increased by at least 10%, preferably by at least 20% and preferably by at least 30% compared to an unembossed version. The values were determined analogously to DIN EN ISO 1924-2.

In a further preferred embodiment, the packaging material has a flexural rigidity which is between 2.0 mN and 6.0 mN in MD, preferably between 2 mN and 4 mN, and between 5.0 mN and 13.0 mN in TD. The flexural rigidity is preferably reduced by at least 60%, preferably by at least 50% and preferably by at least 40% in MD compared to an unembossed version, and increased by at least 50%, preferably by at least 70% and preferably by at least 90% in TD.

Preferably, in a given direction, a rotation (of a section of the packaging material relative to another section of the packaging material) of at least 180° is possible without the packaging material tearing. Particularly preferably, a rotation of at least 360°, preferably of at least 540° and particularly preferably of at least 720° is possible.

In particular, crack-free means that the packaging material has no visible damage, particularly to the surface, after the twisting process, and in particular damage that is visible to the naked eye. Surprisingly, the applicant was unable to detect any visible damage to the surface of a packaging material produced with the above-mentioned values, despite the mechanical stress on the packaging material during the twisting process. Although small amounts of fiber cracks may occur in the base layer, these have no negative impact on the twisting process and do not lead to any visible damage to the surface in the form of cracks, holes, etc. These fiber cracks also do not affect the visual impression of the packaging. In particular, crack-free means that marginal visible changes to the surface of the base material, for example in the form of microcracks, holes, etc., up to a maximum size of 1 mm are acceptable.

This means that one area of the packaging material can be rotated relative to another by up to two or even several revolutions. This axis of rotation particularly preferably runs transversely to the machine direction (TD). However, it would also be possible for it to run in another direction, particularly along the machine direction.

In a further preferred embodiment, the packaging material is flexible. In a preferred embodiment, the structure and/or embossing is distributed uniformly over the entire surface. However, it would also be possible to provide embossing only in the areas in which turning or twisting is to take place.

In a further preferred embodiment, the structure is manufactured with the aid of at least one embossing cylinder.

In a preferred embodiment, the packaging material is wax-free.

Particularly preferably, the structure has a plurality of lines which preferably run parallel to one another.

Particularly preferably, the structure has an embossed pattern which is selected from a group of embossed patterns which includes worm embossing, linen embossing, line embossing, wave embossing, grid embossing, dot embossing, needle embossing, damask embossing, image embossing, lettering embossing, Breille embossing or combinations thereof.

Preferably, this embossing can spatially deform the material in order to increase its elasticity. The material is preferably changed in a relief-like manner. The lines can be straight or curved, for example snake-like. In addition, it is also possible for a first group of lines to run in a first direction and a second group of lines to run in a second direction. These directions can be diagonal or perpendicular to each other.

Furthermore, it is possible that some of the lines run in the longitudinal direction and some of the lines run in a width direction.

In a further preferred embodiment, the embossing has an embossing depth which is between 5 and 100 µm, preferably between 50 µm and 90 µm, preferably between 40 and 70 µm, particularly preferably between 30 µm and 50 µm, particularly preferably between 7 and 25 µm.

It is possible for the embossing to protrude in one direction of the material or in both directions. The embossing can be used as a steel/steel embossing, for example.

In a further advantageous embodiment, a print and/or a finish is arranged on at least one surface and preferably on the first surface. All methods known from the prior art can be used as printing methods and preferably gravure printing, flexographic printing or digital printing. In the context of the invention, finishing is understood to mean everything that is visually or haptically perceptible to the consumer. In particular, the finishing is an overprint varnish or gloss varnish.

In a further advantageous embodiment, a sealing medium is arranged on the outer surface opposite the print.

The sealing medium is preferably a hot-sealing varnish and/or a cold-sealing coating. It is possible that this sealing coating can be activated thermally or by pressure.

As mentioned, the invention therefore proposes a method and a composition for making paper twistable and in particular twistable with modern machines, without using wax. In order to make the paper soft and protect it from tearing, embossing or structuring the paper is proposed, as mentioned above. This embossing makes the paper elastic and flexible and is therefore ideal for twist applications. This has already been confirmed in extensive experiments. A machine test showed excellent results, even with high-speed twist machines.

In a further preferred embodiment, a barrier layer is preferably arranged on the first surface. This is preferably a barrier layer which contains at least one substance selected from a group comprising a metal, a semimetal, a metal oxide, a semimetal oxide, aluminum, copper, titanium, gold, silver, aluminum oxide (AlOx), silicon oxide (SiOx), or mixtures thereof.

In a further preferred embodiment, the base layer comprises at least one, preferably two further layers in the form of primers. This is preferably a pre-metallization primer, i.e. a primer which is applied below the metallization or barrier layer, and a post-metallization primer, i.e. a primer which is applied above the metallization or barrier layer. In a preferred embodiment, a barrier lacquer layer, in particular an oxygen barrier lacquer layer, is designed as a metallization primer.

This barrier layer can preferably provide the packaging material with barrier properties, particularly but not exclusively against Oxygen, water (vapor), aroma and/or fat.

This barrier layer can be applied.

However, it is also possible that such an inorganic coating is used to make the product more visually appealing.

In a further preferred embodiment, the second surface preferably comprises a barrier varnish in addition to or as an alternative to the barrier layer.

In a preferred embodiment, the base layer comprises a coating on the second surface to prevent the contents from subsequently sticking to the packaging material and/or the base layer. In a preferred embodiment, this base layer is based on acrylate and/or ionomers and/or mixtures of these materials.

In a preferred embodiment, the base layer already comprises barrier properties such as, but not exclusively, against fat.

In a further preferred embodiment, a coating is arranged on the carrier material. This coating is particularly preferably arranged over the entire surface.

Particularly preferably, the coating is selected from a group of coatings which includes sticky-release coatings, grease barriers and the like.

In a preferred embodiment, the base layer has a grammage that is greater than 10g/cm ² , preferably greater than 15g/cm ² , preferably greater than 20g/cm ² , preferably greater than 25g/cm ² , and preferably greater than 30g/cm ² .

In a preferred embodiment, the base layer has a grammage that is less than 100g/cm ² , preferably greater than 80g/cm ² , preferably less than 60g/cm ² , preferably less than 50g/cm ² , and preferably greater than 40g/cm ²

In a preferred embodiment, the base layer has a grammage of approximately 35g/cm ² .

The packaging film preferably has an overprint varnish. This is particularly preferably an NC-based overprint varnish. The overprint varnish preferably has a basis weight and/or a grammage that is greater than 0.3g/cm ² , preferably greater than 0.4g/cm ² , preferably greater than 0.5g/cm ² , preferably greater than 0.6g/cm ² , and preferably greater than 0.7g/cm ² .

In a preferred embodiment, the overprint varnish has a basis weight and/or a grammage that is less than 2.0 g/cm ² , preferably less than 1.5 g/cm ² , preferably less than 1.0 g/cm ² , preferably less than 0.9 g/cm ² , and preferably less than 0.8 g/cm ² .

In a further preferred embodiment, the packaging film has a printing ink. This is preferably an NC printing ink.

This printing ink preferably has a basis weight and/or a dry grammage that is greater than 0.5 g/cm ² , preferably greater than 0.7 g/cm ² , preferably greater than 1.0 g/cm ² , preferably greater than 1.3 g/cm ² , and preferably greater than 1.7 g/cm ² .

In a preferred embodiment, this printing ink has a basis weight and/or a dry grammage that is less than 10.0g/cm ² , preferably less than 16g/cm ² , preferably less than 4.0g/cm ² , preferably less than 3.0g/cm ² , and preferably less than 2.5g/cm ²

Preferably, the embossing of the packaging film takes place in one (particularly separate) operation. Particularly preferably, the embossing is carried out using an embossing calender.

The present invention is further directed to a food product which is packaged with a packaging film and/or a packaging material of the type described above.

In this case, a first edge section of the packaging film or the packaging material is preferably twisted relative to a further section and in particular a central section in a first twisting section and preferably a second edge section of the packaging film and/or the packaging material is twisted relative to the central section in a second twisting section.

However, it would also be conceivable that the packaging only has such a twisting section

Preferably, a receiving volume for the food product is formed between the first twisting section and the second twisting section. The food product can be, for example, solid products such as sweets, candies and the like.

The present invention is further directed to a method for producing a packaging material and in particular a packaging material of the type described above.

In a first method step, a carrier material or a base layer (and in particular the above-mentioned base layer), in particular a carrier material (or a base layer) based on cellulose, is provided. In a further and in particular subsequent method step, at least one print and/or at least one coating is arranged on this carrier material. In particular, this print and/or this coating is arranged on at least one surface of the carrier material, which extends in a longitudinal direction and a width direction of the carrier material.

In a further process step, at least one structure is arranged and/or embossed into the carrier material.

Preferably, the carrier material is transported in a predetermined transport direction. Preferably, this transport direction is also the longitudinal direction of the carrier material. Particularly preferably, the printing and/or coating is applied during transport and in particular during a transport movement of the carrier material. In a further preferred method, a transport direction of the carrier material is changed during the embossing process.

In a further preferred method, the carrier material is transported at a transport speed and/or embossing speeds are used which are between 50 and 500 m/min, preferably between 150 and 350 m/min.

In a further preferred method, the coating is selected from a group of coatings which includes sticky-release coatings, grease barriers and the like

In a further preferred method, the arrangement or embossing of the structure is carried out by means of at least one embossing cylinder, with the arrangement or embossing preferably taking place inline. It is possible for the arrangement or embossing to take place immediately after printing or coating. However, it would also be possible for the embossing and/or structuring to take place in a separate operation.

In a further preferred method, the embossing and/or structuring of the carrier material and/or the base layer takes place across its entire width.

In a further preferred method, at least one section of the packaging material is twisted relative to another section of the packaging material.

In particular, this takes place in a further independent operation and in particular in an operation in which a packaged item is packed in the packaging material.

The present invention is further directed to the use of a packaging film and/or a packaging material with an embossed and/or structured layer, in particular an embossed and/or structured paper layer for packaging foodstuffs. This layer is preferably made of a cellulose material.

Particularly preferably, the foods are selected from a group of foods which includes sweets, candies, chocolate and the like.

Particularly preferably, the foodstuffs have a volume which is between 0.25cm ³ and 1300cm ³ , preferably between 0.5cm ³ and 1000cm ³

Preferably, the food items have a weight between 0.5 g/piece and 500 g/piece.

The present invention is further directed to a food product which is packaged in a packaging material of the type described above.

Further advantages and embodiments can be seen in the attached drawings.

• 1 eine Darstellung einer mit einem Produkt versehenen Twistverpackung;
• 2 eine schematische Darstellung einer Basislage einer Verpackungsfolie;
• 3 eine perspektivische Ansicht einer strukturierten Basislage; und
• 4 einen Schichtaufbau einer Verpackungsfolie.

Shown here:

• 1 a representation of a twist pack containing a product;
• 2 a schematic representation of a base layer of a packaging film;
• 3 a perspective view of a structured base layer; and
• 4 a layer structure of a packaging film.

1 shows a representation of a twist packaging 50 provided with a product, here a candy. This has a first packaging section 52 in which the product is packed or is wrapped. The reference numeral 54 designates a first end portion of the package and the reference numeral 56 designates a second end portion of the package.

The reference numerals 55 each identify twist regions which lie between the packaging section 52 on the one hand and the end sections 54 and 56 on the other hand. The twisting occurs in these sections.

2 shows a view of the base layer. This extends here in a longitudinal direction L and in a width direction B that is perpendicular to the longitudinal direction. A thickness direction is perpendicular to the longitudinal direction and the width direction and therefore in the 2 perpendicular to the figure plane.

The reference number 22 designates a first section of the base layer 2, which is twisted relative to a second section 24 of the base layer when the product is packaged. The reference number 26 designates a third section of the base layer, which is also twisted relative to the second section 24 of the base layer when the product is packaged.

The reference numerals 28 and 29 identify the twist sections in which the twisting or twisting is carried out. In these areas, the base layer is structured, as indicated by the hatching. However, it would also be conceivable and preferred that the sections 22, 24 and 26 also have a structure, at least partially or preferably. The entire base layer is particularly preferably structured and/or embossed.

3 shows an example of such a structure of the twist section 28. This has a large number of elevations 28a, which are evenly distributed over the surface of the twist section. As explained above, however, other designs of the twist section can also be selected.

4 shows a schematic representation of a layer structure of a packaging film according to the invention. This has the base layer 2, which has a first surface 2a and a second surface 2b.

A coating 4 is arranged on the first surface 2a. In addition, a print 6 can be arranged on the surface 2a or on the coating 4. Furthermore, at least one further optional layer can also be arranged on the second surface 2b.

In the 3 The elevations 28a shown extend advantageously in the 4 shown thickness direction D

4 shows a further embodiment of a packaging film according to the invention. In addition to the 3 In the layers shown, a primer 32 is advantageously arranged on the coating 4. Preferably, a print 6 is also provided, which is advantageously arranged on the primer 32 but could also be arranged on the coating 4.

Preferably, an overprint varnish 34 is also arranged on the print 6.

The reference numeral 38 designates an optional further primer, which is preferably arranged between the coating 4 and the base layer 2.

The reference number 42 designates a barrier coating and in particular a barrier varnish. Preferably, a further coating, in particular a sticky release coating 44, is also provided, in particular on this barrier coating. Finally, a sealing medium is preferably also provided. Preferably, this sealing medium 46 represents an external layer with respect to the packaging film.

The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided that they are new individually or in combination compared to the prior art. It is also pointed out that the individual figures also describe features that can be advantageous in themselves. The person skilled in the art will immediately recognize that a particular feature described in a figure can also be advantageous without adopting further features from this figure. The person skilled in the art will also recognize that advantages can also arise from a combination of several features shown in individual or different figures.

Claims (13)

Cellulose-based packaging film (1) for packaging foodstuffs as twist packaging, wherein this packaging film (1) has a base layer (2) which extends in a longitudinal direction (L), a width direction (B) perpendicular to the longitudinal direction (L) and a thickness direction (D) perpendicular to the longitudinal direction (L) and the width direction (B), and wherein the base layer has a first surface (2a) which extends in the longitudinal direction (L) and the width direction (B) and a second surface (2b) which extends in the longitudinal direction (L) and the width direction direction (B) and which is opposite the first surface (2a) and wherein the base layer (2) is made of paper and/or cellulose-containing material, characterized in that the base layer (2) has a structure and/or embossing at least in sections, such that a first section (22) of the base layer (2) can be rotated by at least 180° relative to a second section (24) of the base layer with respect to at least one axis of rotation, in order to thus form the twist packaging - in particular without cracks. Packaging film (1) to Claim 1 , characterized in that the packaging film (1) is wax-free. Packaging film (1) according to at least one of the preceding claims, characterized in that the structure has a plurality of lines which preferably run parallel to one another or the structure has an embossed pattern which is selected from a group of embossed patterns which includes worm embossing, linen embossing, line embossing, wave embossing, grid embossing, dot embossing, needle embossing, damask embossing, image embossing, lettering embossing, Braille embossing or combinations thereof. Packaging film (1) according to at least one of the preceding claims, characterized in that the embossing has an embossing depth (T) which is between 5 µm and 100 µm, preferably between 50 µm and 90 µm, preferably between 40 µm and 70 µm, particularly preferably between 30 µm and 50 µm and especially preferably between 7 µm and 25 µm. Packaging film (1) according to at least one of the preceding claims, characterized in that a print is arranged on the first surface. Packaging film (1) according to at least one of the preceding claims, characterized in that an inorganic barrier layer is arranged on the first surface (2a), which contains at least one substance selected from a group comprising a metal, a semimetal, a metal oxide, a semimetal oxide, aluminum, copper, titanium, gold, silver, aluminum oxide (AlOx), silicon oxide (SiOx), or mixtures thereof. Packaging film (1) according to at least one of the preceding claims, characterized in that a coating is arranged on the base layer and preferably the coating is selected from a group of coatings which contains sticky-release coatings, grease barriers and the like. Food product packaged in packaging material (1) according to at least one of the preceding claims. Method for producing a packaging material and in particular a packaging material according to at least one of the preceding claims with the steps: - Providing a cellulose-based carrier material - Arranging at least one print and/or at least one coating on this carrier material - Arranging and/or embossing at least one structure in the carrier material Method according to the preceding claim, characterized in that the coating is selected from a group of coatings which includes sticky-release coatings, grease barriers and the like. Method according to at least one of the preceding claims, characterized in that the arrangement or embossing of the structure is carried out by means of at least one embossing cylinder, wherein the arrangement or embossing preferably takes place inline. Method according to at least one of the preceding claims, characterized in that at least one section of the packaging material is rotated relative to another section of the packaging material. Use of a packaging film and/or a packaging material with an embossed and/or structured layer, in particular an embossed and/or structured paper layer, for packaging foodstuffs.