PACKAGING MATERIAL, METHOD FOR PRODUCING THE PACKAGING MATERIAL AND ITS USE

Description

[0001] The invention relates to a packaging material according to the preamble of patent claim 1, a method for producing such a packaging material according to the preamble of patent claim 9 and the use of such a packaging material according to the preamble of patent claim 10.

[0002] Such packaging materials are usually required and used as so-called "medical papers" and are used to manufacture and / or seal containers and packaging, especially medical ones.

[0003] Such packaging materials, namely "medical papers," are typically based on a paper-based packaging base material that is coated in such a way that it can be bonded, in particular glued or sealed, to a counterpart. It is important, on the one hand, that the packaging material, or rather the "medical paper," can be cleanly detached from the counterpart to open the package without the packaging base material tearing during the opening process. Furthermore, it must be ensured that, once the package has been opened, the packaging cannot be resealed with the "medical paper," so that it is clearly recognizable that the package has already been opened.

[0004] According to the current state of the art, such packaging materials were produced by coating the paper-based packaging base material with hot melt adhesive, which was applied either in the form of a hot melt adhesive solution in toluene or directly to the paper.

[0005] However, this process and the packaging materials produced with it have significant disadvantages. When the hot melt adhesive is applied to the paper using a solvent, a high proportion of residual solvent remains in the packaging material and the end product therefore contains toluene.

[0006] Furthermore, with such a solvent-based hot melt adhesive application, the application weight of the hot melt adhesive is very high, ranging from 6 g / m² to 11 g / m² and higher. This high application weight of the hot melt adhesive leads to a very high final product weight and, due to the thick hot melt adhesive layer, to an exacerbation of the residual solvent problem, as the hot melt adhesive acts as a sink for the solvent toluene.

[0007] In contrast, direct hot melt adhesive application has the disadvantage of slowing down the machine speed during packaging material production, thus reducing plant productivity. Furthermore, a thick hot melt adhesive application leads to poor hot tack, i.e., poor initial seal strength during container or packaging production and / or closing.

[0008] These disadvantages have an adverse effect on the quality of existing packaging materials used as "medical paper."

[0009] The invention is based on the object of providing a packaging material that is suitable as "medical paper" while avoiding the aforementioned disadvantages, is simple and cost-effective to produce, and, in addition to the sterilizability of a product contained in a package made or sealed with the packaging material, also ensures clean detachability of the packaging material from a counterpart of the package without the possibility of resealing the package with the packaging material. Furthermore, the object of the invention includes providing the production of such a packaging material and its use.

[0010] This object is achieved by a packaging base material according to patent claim 1, by a method for producing such a packaging material according to patent claim 9 and by the use of such a packaging material according to patent claim 10.

[0011] In particular, the object is achieved by a packaging material made of paper or with a paper outer side, wherein the paper outer side, in particular over its entire surface, is coated with a release varnish and the release varnish is coated in a pattern, namely in a grid shape, with a sealing medium.

[0012] An essential point of the invention is that according to the invention a release varnish is applied, in particular over the entire surface, to the outside of the packaging base material made of paper. The release varnish ensures that the coating of the packaging base material, which consists of release varnish and sealing medium, can be completely detached from the packaging base material, i.e. from the paper, according to a first variant, without the paper fibers tearing. When the packaging is opened, the coating of sealing medium and release varnish originally arranged on the packaging base material remains on the counterpart to which the packaging material according to the invention was applied, so that when the packaging material according to the invention is detached from the packaging or when the packaging is opened, it is more or less delaminated and thereby destroyed, so that resealing of the packaging is not possible under any circumstances and is therefore reliably avoided.

[0013] According to the invention, the release varnish can be arranged only in the areas of the packaging material according to the invention that are to be sealed or, if desired, also over the entire surface of the packaging base material.

[0014] The sealing medium, in turn, is arranged in a pattern, i.e., a grid pattern, on the release coating. The sealing medium can also be applied in a limited manner to the areas of the packaging material according to the invention that are to be sealed.

[0015] According to a second variant of the invention, which also ensures that the packaging material according to the invention is structurally altered and thereby destroyed upon detachment from the packaging or upon opening the packaging, so that reclosure of the packaging is no longer possible under any circumstances and is thus reliably prevented according to the invention, a portion of the release lacquer remains on the packaging base material. In this case, the release lacquer is broken upon opening the packaging, for example, and remains essentially at those points on the packaging base material where the release lacquer is not coated with sealing medium in an intact packaging material. In this variant, the release lacquer is therefore not completely separated from the packaging base material; however, the sealing medium remains entirely on the counterpart with which the sealing medium was sealed during formation and / or closing of the container or packaging.

[0016] A further significant advantage of applying the sealing medium in a patterned manner is that the packaging material according to the invention retains a high gas permeability when the sealing medium is not applied over the entire surface, so that the packaged product can be sterilized with ethylene oxide without any problems even in the case of a package produced and / or sealed with the packaging material according to the invention.

[0017] According to the invention, the release varnish according to the invention is a polyamide-based release varnish and, when the packaging is opened, ensures, on the one hand, problem-free detachment from the packaging base material and, in addition, also ensures sufficient adhesion between the release varnish and the sealing medium.

[0018] According to the invention, the sealing medium is selected from a group that seals against polyolefin(s), in particular polyethylene or polypropylene, and / or against polyester, in particular polyethylene terephthalate, and / or against paper and / or against polystyrene or mixtures of the aforementioned substances and comprises polyolefin(s), in particular polyethylene or polypropylene, polyester, in particular polyethylene terephthalate, or mixtures of the aforementioned substances, as well as ethylene-vinyl acetate copolymer. These sealing media are common and cost-effective heat-sealable materials that can be sealed against various substrates made, for example, from polyethylene, polypropylene, polyethylene terephthalate, paper, or polystyrene, or that have sealing surfaces with or made of these materials. Thus, with the aforementioned sealing materials, optimal seal seam strengths in the range from 1.0 N / 15 mm to 2.0 N / 15 mm can advantageously be achieved.

[0019] According to one embodiment of the invention, the sealing medium is applied to the release lacquer in the form of a dispersion which consists of a mixture of water and ethylene-vinyl acetate copolymer and optionally a proportion of an alcohol, in particular ethanol, propanol, isopropanol or butanol, in the range from 0.01 wt.% to 8 wt.%, preferably in the range from 0.1 wt.% to 6.5 wt.% and particularly preferably in the range from 3.5 wt.% to 5 wt.% and / or optionally a further sealing medium.

[0020] According to an alternative according to the invention, the dispersion comprises no further, in particular no further organic, solvent apart from water and ethylene-vinyl acetate copolymer.

[0021] According to a preferred embodiment of the invention, this dispersion is a heat-seal dispersion.

[0022] According to the invention, the sealing medium is applied to the release varnish with an application weight in the range from 0.5 g / m 2< to 6 g / m 2< , preferably in the range from 1.5 g / m 2< to 5 g / m 2< and particularly preferably in the range from 2 g / m 2< to 4 g / m 2<. Such an application weight enables the production of a lightweight packaging material and thus the production of lightweight packaging. At the same time, such an application weight and the associated amount of sealing medium ensure optimal sealing with the respective counterpart of the packaging material according to the invention, both with regard to the tightness of the packaging and with regard to the seal strength of the seal seam even when the seal seam is hot, and thus optimal hot tack.

[0023] As already mentioned, the packaging material according to the invention is gas-permeable, so that ethylene oxide sterilization of the product contained in a package produced and / or sealed with the packaging material is easily possible. The gas permeability of the packaging material according to the invention is essentially ensured by the fact that the packaging base material of the packaging material according to the invention consists of paper and / or has at least one paper layer facing the release coating, which consists of fibers whose interweaving is gas-permeable. The paper material used to produce the packaging material is plasma-treated according to the invention, which advantageously prevents fraying of the paper.

[0024] According to the invention, the release coating is applied to the paper layer in a gas-permeable layer thickness.

[0025] Furthermore, the packaging material according to the invention is a medical paper.

[0026] Furthermore, the object of the invention is also achieved by a method for producing a packaging material according to the above statements, wherein the following steps are carried out: Providing a packaging base material made of paper or with a paper outer surface; in particular, coating the entire outer surface of the paper with a release coating; and applying a sealing medium to the release coating, at least in sections and in a grid-like manner.

[0027] Furthermore, the object of the invention is also achieved by using a packaging material with the above properties for producing a container, in particular a medical container.

[0028] In summary, the subject matter of the invention can be described as follows: The packaging material according to the invention can be used in the field of and / or as "medical paper" and meets all the requirements placed on a "medical paper." The packaging material according to the invention comprises a sterilizable and heat-sealable coating on paper and is sealable to various substrates, such as predominantly polyethylene, but also to polypropylene and / or polyethylene terephthalate, as well as to paper and polystyrene, and if desired, also to mixtures of the aforementioned polyolefins and / or other materials. The packaging material according to the invention enables a clean peel without paper fiber tear, with the coating of the packaging base material transferring completely to the opposite side, i.e., the counterpart to be sealed, so that the packaging cannot be resealed and an opening of the packaging is directly recognizable.Resealing a package once sealed with the packaging material according to the invention and then opened is not possible. The seal seam strength achievable with the packaging material according to the invention is in the range of 1.0 N / 15 mm to 2.0 N / 15 mm.

[0029] Since the dispersion used according to the invention, in particular heat-sealing dispersion, contains no solvent, in particular no other or further organic solvent, except for alcohol, the presence of such other organic solvent residue, as was to be feared in the prior art, is excluded in the packaging material according to the invention.

[0030] Advantageously, the coating of the packaging material according to the invention consisting of release varnish and / or sealing medium can be applied to the packaging base material by means of gravure printing, which can advantageously be carried out not only very quickly at a high machine speed, but also very precisely and with the creation of a pattern-like application.

[0031] The packaging material according to the invention thus comprises an application, in particular over the entire surface, of a polyamide-based release coating which does not prevent ethylene oxide sterilization and ensures clean detachment of the heat-seal coating from a respective counterpart.

[0032] The heat-seal coating is characterized by its good hot tack and wide processing window on a packaging machine, as well as its ability to seal against a variety of substrates, such as polyethylene, polypropylene, polyethylene terephthalate, polystyrene, or paper. Furthermore, the use of a dispersion minimizes the risk of an increased residual solvent content or, depending on the dispersion used, eliminates it entirely. The heat-seal dispersion is preferably applied as a grid, which ensures that a package produced with the packaging material according to the invention can be sterilized with ethylene oxide.

[0033] The combination of a fully applied release coating and a heat-sealing dispersion applied in a grid pattern simultaneously ensures a clean transfer of the release coating and sealing medium from the paper without the risk of fiber tearing of the paper to the opposite web. Furthermore, the fully applied release coating and the grid-patterned heat-sealing dispersion ensure sufficient adhesion between the release coating and the heat-sealing dispersion, as well as optimal cohesive strength in the release coating to achieve the required peel force.

[0034] The particularly good sealing properties of the heat-seal dispersion allow for a significantly lower coating weight. This, in turn, allows for optimal, increased efficiency on the coating line.

[0035] Further embodiments of the invention emerge from the subclaims.

[0036] The invention is described below with reference to exemplary embodiments, which are explained in more detail with reference to the figures. Fig. 1 is a schematic representation of an embodiment of the invention; and Fig. 2 is a schematic representation of the embodiment of the invention according to Fig. 1 , wherein the packaging material according to the invention is first connected to a counterpart and then separated from it again.

[0037] In the following description, the same reference numbers are used for identical and equivalent parts.

[0038] Fig. 1 shows an embodiment of a packaging material 10 according to the invention, which consists of a packaging base material 12 made of plasma-treated paper with a basis weight of 60 g / m 2<, on which, as in Fig. 1 As shown, a polyamide-based release coating 20 is applied over the entire lower surface with an application weight of 1.5 g / m 2 . A sealing medium 30 is applied to this release coating 20 in a grid pattern, with the application weight of the sealing medium being 3 g / m 2 .

[0039] In Fig. 2 is a schematic representation of the embodiment of the invention according to Fig. 1, wherein the packaging material 10 according to the invention is first connected to a counterpart 40 and then separated therefrom again. For this purpose, the packaging material 10 according to the invention is first brought together with the counterpart 40 in such a way that the sealing medium 30, which is connected to the packaging base material 12 via the release varnish 20, is brought to the counterpart 40, in this case polyethylene, and sealed thereto. The counterpart 40, in turn, is arranged on a carrier material 42. According to the invention, ethylene-vinyl acetate copolymer is used as the sealing medium 30, which seals against polyethylene with optimal sealing force. When the packaging material 10 according to the invention is separated from the counterpart 40, the sealing medium 30 remains on this counterpart 40.Furthermore, with the sealing medium 30, a portion of the release varnish 20 remains on the counterpart 40, wherein the release varnish 20 breaks upon separation of the packaging material 10 according to the invention from the counterpart 40 and remains on the packaging base material 12 in the areas in which, in an intact packaging material 10, no sealing medium 30 was arranged on the release varnish 20 before the packaging material 10 was bonded to the counterpart 40. Thus, if an attempt were made to rebond the remaining packaging base material 12 with the release varnish, a layer also consisting of release varnish would be opposite the counterpart 40, making rebonding of the packaging base material 12 to the counterpart 40 impossible.

[0040] According to a further embodiment of the invention, a plasma-treated paper web 12 with a basis weight of 80 g / m² is fully coated with a polyamide-based release coating 20. The release coating 20 is applied with a basis weight of 1.6 g / m². An aqueous heat-sealing dispersion 30 with a basis weight of 3.1 g / m² is then applied in a grid pattern to this release coating 20.

[0041] At this point, it should be noted that all parts described above, viewed individually and in any combination, particularly the details shown in the drawings, are claimed as essential to the invention. Modifications to these are familiar to those skilled in the art. List of reference symbols

[0042] 10Packaging material 12Packaging base material 15Paper outer side 20Release varnish 30Sealing medium 40Counterpart 42Carrier material of the counterpart

Claims

1. Packaging material (10) made of paper or with a paper outer side, in particular for medical purposes, characterized in that the paper outer side (15) is coated, in particular over the entire surface, with a release lacquer (20) and the release lacquer (20) is coated in a patterned manner, namely in a grid pattern, with a sealing medium (30), wherein the release lacquer (20) is a polyamide-based release lacquer (20).

2. Packaging material according to one of the preceding claims, characterized in that the sealing medium (30) is selected from a group that is impermeable to polyolefin(s), in particular polyethylene or polypropylene, and / or against polyester, in particular polyethylene terephthalate, and / or against paper and / or against polystyrene or mixtures of the aforementioned substances, and comprises polyolefin(s), in particular polyethylene or polypropylene, polyester, in particular polyethylene terephthalate, or mixtures of the aforementioned substances, as well as ethylene-vinyl acetate copolymer.

3. Packaging material according to one of the preceding claims, characterized in that the sealing medium (30) is applied to the release lacquer (20) in the form of a dispersion.

4. Packaging material according to claim 3, characterized in that the dispersion is a mixture of water and ethylene-vinyl acetate copolymer and, optionally, a proportion of an alcohol, in particular ethanol, propanol, isopropanol or butanol, in the range of 0.01 wt.% to 8 wt.%, preferably in the range of 0.1 wt.% to 6.5 wt.% and particularly preferably in the range of 3.5 wt.% to 5 wt.%, and / or optionally a further sealing medium.

5. Packaging material according to claim 3, characterized in that the dispersion does not contain any solvent other than water, in particular no other organic solvent, and is in particular a heat-sealing dispersion.

6. Packaging material according to one of the preceding claims, characterized in that the sealing medium (30) is applied to the release lacquer (20) with an application weight in the range of 0.5 g / m2 to 6 g / m2, preferably in the range of 1.5 g / m2 to 5 g / m2 and particularly preferably in the range of 2 g / m2 to 4 g / m2.

7. Packaging material according to one of the preceding claims, characterized in that the packaging material (10) is gas-permeable.

8. Packaging material according to one of the preceding claims, characterized in that the packaging material (10) is a medical paper.

9. Method for producing a packaging material (10) according to one of the preceding claims, characterized by the following steps: - providing a packaging base material (12) made of paper or having a paper outer side (15); - in particular, coating the paper outer side (15) over its entire surface with a release lacquer (20); - and applying a sealing medium (30) to the release lacquer (20) at least in sections in a grid pattern.

10. Use of a packaging material (10) according to one of the preceding claims 1 to 8 for manufacturing a container, in particular a medical container.