RU2778316C2 - Packaging material and method for its manufacture - Google Patents

Abstract

FIELD: packaging technology.

SUBSTANCE: invention relates to packaging material. The packaging material contains a pre-stretched and thermally stabilized elastic film (1) and an elastic polymer mesh flatly located on the film, the polymer mesh is connected to the film (1) by means of a layer of adhesive applied to the film (1), and the adhesive substance is a water-soluble adhesive with low adhesion, so that at high tensile stresses, the possibility of relative movement of the film (1) and the polymer mesh relative to each other is provided.

EFFECT: creation of a packaging material with a low weight relative to its dimensions and high tensile strength at high tensile stresses.

9 cl, 4 dwg

Description

The invention relates to a packaging material in accordance with the restrictive part of paragraph 1 of the claims. The invention also relates to a method for manufacturing the packaging material according to the invention.

From the Applicant's publication WO 2017/080609, a packaging material is known with a first film and fabric, which are positioned one above the other and interconnected. When this first film contains the first area in which the first film is locally stretched, and the second area in which the first film is not locally stretched; the first regions are respectively located between the two second regions and extend in the first direction, wherein the fabric contains a thread and part of the thread extends in a direction that intersects the first direction.

However, in certain applications where heavy materials are to be packaged, the prior art packaging material may undesirably break at certain locations due to varying degrees of tensile stress between the film and the fabric.

Such packaging materials are used to pack pallets, agricultural products, garbage, etc., so high tear strength is required as well as weather protection. In addition, such packaging materials should contain as little polymer as possible, which, on the one hand, reduces the burden on the environment and, on the other hand, translates into more favorable prices for the consumer.

The present invention is based on the problem of providing a packaging material with low weight in relation to its dimensions and high tensile strength at high tensile stresses. In addition, a method is provided for the manufacture of a packaging material according to the invention.

This problem is solved using the features of claim 1 of the claims. The method of manufacturing the packaging material according to the invention is the subject of claim 8 of the claims. Other inventive embodiments and advantages follow from the respective dependent claims.

In accordance with this, a packaging material is proposed that contains a pre-stretched and heat-stabilized elastic film and an elastic polymer network laid flat on the film, in particular, a polymer network made in the form of an elastic mesh, the polymer network being connected to the film by means of an adhesive layer deposited on the film. substances in such a way that at high tensile stresses it is possible to move the film and the polymer network relative to each other.

Due to the pre-stretching of the elastic film, the packaging material advantageously becomes thinner and lighter in relation to the predetermined length, and the thermal stabilization of the pre-stretched film leads to the absence of residual surface stresses on the film surface. Thanks to the concept according to the invention, at high tensile stresses, it is possible to uniformly distribute local overstresses that occur at different points in the packaging material by relative movement of the mesh and the film relative to each other, so that tearing of the packaging material is advantageously prevented. This is ensured by the fact that the adhesive is a water-soluble adhesive, such as food adhesive, with low adhesion.

In addition, by preventing local overstresses, the packaging material can be wound on light and thin winding sleeves instead of heavy pressboard winding cylinders.

For the production of the packaging material according to the invention, the elastic film is pre-stretched to a certain, predetermined degree and then thermally stabilized, and then a layer of adhesive is applied to the pre-stretched film, for example a layer of water-soluble adhesive with low adhesion, for example using cylindrical axles or high-pressure nozzles. After pre-stretching of the film, it has a residual elasticity of at least 20%.

At the next stage, the film and the polymer mesh are pressed together with the help of rolls, as a result of which a packaging material is formed, one side of which is made in the form of a self-adhesive film covered with a polymer mesh without constriction points. Due to the self-adhesive design, in addition, there is an advantage that it is easier to seal the packaging material after receiving the goods.

The elastic film can be pre-stretched, for example, to a thickness of 5 μm, and the width can be any and, for example, be in the range from 40 cm to 380 mm. The elastic film can be made, for example, from LLDPE (linear low density polyethylene), LDPE (low density polyethylene), HDPE (high density polyethylene), PVC (polyvinyl chloride), EVA (ethylene vinyl acetate) or a similar polymer, in particular from any polyolefin, or contain it.

The polymer mesh can be made from polyolefins such as, for example, LLDPE (linear low density polyethylene), LDPE (low density polyethylene), HDPE (high density polyethylene), PVC (polyvinyl chloride), EVA (ethylene vinyl acetate) or a similar polymer or contain his. Its weight may be, for example, from 2 to 32 grams per linear meter, and the mesh density may be, for example, in the range from 6 needles/inch to two inches of needle spacing. The width of the mesh essentially corresponds to the width of the elastic film.

The mesh may also consist of chains (also called warp threads) running in the direction of the mesh extension and weft threads which join the strings into a mesh in a zigzag pattern, which are woven under each other according to the prior art, the strings being respectively formed from one thread. It can also be provided that all or part of the chains, in particular the outer chains, are respectively formed from two or more threads to increase strength.

The distance between the chains can be any and can be, for example, in the range from 4.2 to 50.8 mm. The polymer filaments used for the chains may have a thickness of 10-60 microns or less.

In addition, at least the outer chains or any chains can respectively comprise two or more partial chains for increased strength, which are connected to each other by means of at least a zigzag weft thread in such a way that the partial chains run directly side by side parallel to each other. For chains containing two partial chains, the partial chains are linked together in pairs by means of at least one weft thread.

The invention is explained in more detail below by way of example based on the attached figures. The drawings show:

Fig. 1a is a schematic sectional view of a packaging material according to a first embodiment of the invention;

Fig. 1b is a schematic plan view of the packaging material of FIG. 1a;

Fig. 2 is an enlarged view of FIG. 1b;

Fig. 3a is a schematic sectional view of a packaging material according to a second embodiment of the invention;

Fig. 3b is a schematic plan view of the packaging material of FIG. 3a; and

Fig. 4 is an enlarged view of FIG. 3a.

In FIG. 1b and 2b, the reference symbol MD denotes the machine direction, namely the direction of extension of the polymer network in the manufacture, respectively, of the packaging material in winding; the reference symbol TD denotes the transverse direction, namely the direction perpendicular to the machine direction or, respectively, to the direction of extension.

In accordance with the invention and with reference to the exemplary embodiment of FIG. 1a and 1b, the packaging material comprises a pre-stretched and heat-stabilized film 1 and a polymer network of substantially equal width laid flat on the film 1, which is connected to the film 1 by means of an adhesive layer 2 deposited on the film 1 in such a way that, at high tensile stresses, it is possible to relative movement of the film 1 and the polymer network relative to each other. In this case, the polymer mesh constantly remains in contact with the adhesive layer 2 .

The polymer mesh located on the film 1 and connected to the film 1 can be made in the form of a raschel mesh in accordance with the prior art, containing chains 3 passing in the direction of the length of the mesh and weft threads 4 that connect the chains into a mesh with the formation of a zigzag pattern. The distance between adjacent chains 3 can be, for example, between 4.2 mm and 50.8 mm.

Shown in FIG. 3a, 3b and 4, the embodiment differs from the embodiment of FIG. 1a, 1b and 2 in that all strands 3 for strength increase respectively comprise two partial strands 3a and 3b, which are connected to each other by means of a zigzag weft thread 4 in such a way that the partial strands 3a, 3b run directly side by side parallel to each other. . The distance between the partial chains 3a, 3b of the chain 3, i.e. the distance between the virtual center lines of the partial chains relative to each other, can be, for example, in the range of 2 mm to 10 mm, preferably 2 mm to 5 mm. At such small distances, the partial chains 3a, 3b can come into contact.

The polymer mesh can be produced using a raschel machine, which respectively contains at least two eyelets for guiding the respective polymer thread for knitting a respective one chain, wherein the respective two eyes are fixed on a common eyelet holder, and correspondingly two eyes can be associated with two needles attached to common needle bar. In this case, the distance between two adjacent eyelets and/or between two immediately adjacent needles can be from 2 to 10 mm, in particular from 2 to 5 mm, as a result of which it is possible to easily manufacture chains in the normal operation of the raschel machine.

Claims (9)

1. A packaging material containing a pre-stretched and heat-stabilized elastic film (1) and an elastic polymer mesh laid flat on the film, characterized in that the polymer mesh is connected to the film (1) by means of an adhesive layer deposited on the film (1), and the adhesive the substance is a water-soluble adhesive with low adhesion, so that at high tensile stresses, the relative movement of the film (1) and the polymer network relative to each other is provided. 2. Packaging material according to claim 1, characterized in that the elastic film (1) is pre-stretched to a thickness of 5 µm and has a residual elasticity of at least 20%. 3. Packaging material according to claim 1, characterized in that it has a width of 40 cm to 380 cm. 4. Packaging material according to paragraphs. 1-3, characterized in that the elastic film (1) is made of linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), polyvinyl chloride (PVC), ethylene vinyl acetate (EVA) or a similar polymer or contains it. 5. Packaging material according to paragraphs. 1-4, characterized in that the polymer mesh is made of LLDPE, LDPE, HDPE, PVC, EVA or a similar polymer or contains it. 6. Packaging material according to paragraphs. 1-5, characterized in that the polymer mesh consists of chains (3) passing in the direction of the length of the mesh and weft threads (4), which connect the chains (3) into a mesh with the formation of a zigzag pattern, and the chains (3) are formed, respectively, from one threads, or all chains (3) or part of them, to increase strength, are respectively formed from two or more threads. 7. Packaging material according to claim 6, characterized in that, in order to increase the strength, at least the outer chains (3) respectively contain two or more partial chains (3a, 3b), which, with the help of at least one weft thread (4) passing in a zigzag ) are interconnected in such a way that the partial chains (3a, 3b) run directly adjacent and parallel to each other. 8. A method of manufacturing a packaging material made according to one of the preceding claims, characterized in that the elastic film (1) is pre-stretched to a certain, predetermined degree and then subjected to thermal stabilization, after which a layer (2) of adhesive is applied to the pre-stretched film (1). substances, and the adhesive is a water-soluble adhesive with low adhesion, and at the next stage, the film (1) and the polymer mesh are pressed with rollers, as a result of which a packaging material is obtained, one side of which is made in the form of a self-adhesive film covered with a polymer mesh ( 1) without places of constriction, and at high tensile stresses, the possibility of relative movement of the film (1) and the polymer network relative to each other is provided. 9. Method according to claim 8, characterized in that the adhesive is applied using high-pressure nozzles or cylindrical axles.

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