ES1230589Y1 - Flexible plastic material band for making plastic mesh bags - Google Patents

Abstract

1. Flexible plastic material band (1), applicable for the manufacture of plastic material mesh bags in which said band (1) is heat-welded to the mesh, said band (1) comprising: - an inner sheet (2) made of plastic, designed to face the bag and to be heat-sealed to said bag; - an outer plastic sheet (3), transparent to visible light, intended to face the outside of the bag; - a layer of printing ink (4) arranged between said inner sheet (2) and said outer sheet (3); - a layer of adherent material (6) arranged between said inner sheet (2) and said outer sheet (3) to join them: and - a plurality of luminescent marks (5), visible when said band (1) is irradiated with ultraviolet light or infrared, said luminescent marks (5) being arranged at regular intervals along said band (1); characterized in that said layer of printing ink (4) is translucent to visible light and is applied directly on an inner face (7) of said outer sheet (3), facing said inner sheet (2), said luminescent marks ( 5) are arranged directly on said layer of printing ink (4), separated from said inner face (7) of the outer sheet (3) by said layer of printing ink (4), and said layer of adherent material (6 ) is applied directly on said layer of printing ink (4) and directly on said luminescent marks (5), and because said luminescent marks (5) are not transparent to visible light. 2. Band (1) according to claim 1, characterized in that said luminescent marks (5) are formed by a continuous zone (8) of luminescent material that surrounds an empty part (9) devoid of said luminescent material, so that said empty part (9) forms an alphanumeric indication. 3. Band (1) according to any of claims 1 or 2, characterized in that said luminescent marks (5) form strips that extend transversely to said band (1).

Description

DESCRIPTION

FLEXIBLE BELT OF PLASTIC MATERIAL FOR THE MANUFACTURE OF BAGS OF

PLASTIC MATERIAL MESH

Field of the Invention

The invention is in the field of plastic material bands that are heat-sealed to plastic material mesh bags.

More specifically, the invention relates to a flexible plastic material band, applicable for the manufacture of plastic material mesh bags in which said band is heat-welded to the mesh, of the type comprising:

- an inner plastic sheet, intended to face the bag and to be heat-sealed to said bag;

- an outer plastic sheet, transparent to visible light, intended to face the outside of the bag;

- a layer of printing ink disposed between said inner sheet and said outer sheet;

- a layer of adherent material arranged between said inner sheet and said outer sheet to join them; and

- a plurality of luminescent marks, visible when said band is irradiated with ultraviolet or infrared light, said luminescent marks being arranged at regular intervals along said band.

State of the art

Mesh bags made of plastic material, intended to contain preferably fruit and vegetable products, normally have a flexible strip of plastic material heat-sealed on their sides. During the manufacture of these mesh belt bags, machines fed with a continuous tubular mesh coil forming the bag, and band coils are usually used to apply the band to the sides of the bag.

The bands usually have information, illustrations or printed indications related to the product contained in the bag, and can even be used as handles to grip the bag. In order for the prints or the handle to be well positioned on the mesh bag, or for all the bands to be the same length, the machines that cut the bands have a detector that detects marks arranged at regular intervals in the band, in order to know exactly where they have to make the cross section of the band.

Document ES2398139T3 discloses a flexible strip of the type indicated at the beginning, in which the luminescent marks are arranged directly on the inner face of the outer sheet, the printing ink layer is applied on said luminescent marks and the layer of adherent material is disposed between said layer of printing ink and the inner sheet. In this configuration, when looking at the web from the outside, ie from the side of the outer sheet, the luminescent marks are in the foreground, ahead of the printing ink layer. In order not to obstruct the view of the pattern formed by the printing ink layer, these luminescent marks are transparent to visible light.

Description of the Invention

The invention has for its object to provide a flexible strip of plastic material applicable for the manufacture of plastic mesh bags of the type indicated at the beginning, in which the detection marks do not obstruct the view of the motif formed by the printed ink layer of the band, and at the same time allow automated cutting of the band in a more versatile and reliable way.

This purpose is achieved by means of a flexible strip of plastic material of the type indicated at the beginning, characterized in that the printing ink layer is applied directly on an inner face of the outer sheet, facing the inner sheet, the luminescent marks are arranged directly on said printing ink layer, separated from said inner face of the outer sheet by said printing ink layer, and the adhesive material layer is applied directly on said printing ink layer and directly on said luminescent marks, and by that these luminescent marks are not transparent to visible light, and may be translucent or opaque. These luminescent marks are detected by a detector on a cutting machine equipped with an ultraviolet or infrared light projector. Luminescent marks, not being transparent, can be perceived with the naked eye, making it easy to know if the band is equipped with luminescent marks and is therefore suitable for an assisted cutting procedure with an ultraviolet or infrared light projector. This increases the reliability of the procedure. In the final product (the mesh bag fitted with the band), the luminescent marks do not obstruct the view of the motif formed by the printing ink layer, because these luminescent marks are in the background, behind the printing ink layer. impression, when looking at the band from the side of the outer foil. Another advantage of the invention is that the band manufacturing process is more versatile because it is unnecessary to use a transparent ink to make the luminescent marks.

The printing ink layer is translucent to visible light, so that the luminescent marks are visible by a user looking at the band on the side of the outer sheet 3.

Preferably, the luminescent marks are formed by a continuous area of luminescent material that surrounds an empty part devoid of said luminescent material, so that said empty part forms an alphanumeric indication that allows information on the band to be seen with the naked eye, such as for example, the production date or a control code. The presence of the luminescent marks is thus used to indicate information about the band, even with the naked eye.

The luminescent markings preferably form strips that extend transversely to the band.

The invention also encompasses other detailed features shown in the following detailed description of an embodiment of the invention and in the accompanying figures.

Brief description of the drawings

The advantages and characteristics of the invention are appreciated from the following description in which, without limitation with respect to the scope of the main claim, a preferred embodiment of the invention is set forth with reference to the figures.

Fig. 1 is a perspective view of a flexible plastic web strip coil according to the invention.

Fig. 2 is a plan view of the strip, showing various luminescent markings.

Fig. 3 is an enlarged view of a part of the band of Figure 2.

Fig. 4 is a sectional view of a section of the strip, sectioned along a longitudinal plane.

Detailed description of an embodiment of the invention

Figures 1 to 4 show an embodiment of a flexible strip 1 of plastic material, applicable for the manufacture of plastic material mesh bags in which said band 1 is heat-welded to the mesh of the bag. During the manufacture of the mesh bag, the band 1 is disposed on at least one of the sides of the bag, heat-welded to the mesh and cut to the appropriate length.

Band 1 is used to provide information about the product in the bag and can even be used as a handle. For this reason, the band 1 presents a layer of printing ink 4, which normally forms a commercial motif as well as indications with information about the product (not represented in the figures), and which faces the outside of the bag to that the user can see it. Furthermore, as can be seen in Figure 2, the band 1 has a plurality of luminescent marks 5 that help to identify where the band must be cut so that the information and the motif are well positioned on the mesh bag, or so that all bands have the same length. These luminescent marks 5 are visible when irradiated with ultraviolet or infrared light and are not transparent to visible light, so that they can be detected both by a machine equipped with an ultraviolet or infrared light projector and by an operator with the naked eye, or by an automatic image recognition system that works with visible light. The luminescent marks 5 are made by means of an ink that is luminescent when irradiated with ultraviolet or infrared light. The ink is not transparent to visible light, and can be translucent or opaque.

Luminescent markings are arranged at regular intervals along band 1 and can take various forms. Preferably, the luminescent strips are in the form of strips that extend transversely to the strip, as shown in Figs. 2 and 3. The Strips can be continuous or discontinuous, and can span the entire width of the band or cover only part of that width. In other embodiments (not shown), the luminescent markings may have other geometric shapes. For example, they can be formed by circles, triangles, rectangles, etc., as well as by alphanumeric characters and combinations of tollos themselves. In the embodiment shown in Figure 3, the luminescent markings 5 are formed by a strip comprising a continuous area 8 of luminescent material surrounding an empty part 9 devoid of the luminescent material, so that the empty part 9 forms an indication alphanumeric. These luminescent marks 5 can be used to indicate production codes and dates, or other information related to the product or its manufacture. The alphanumeric indications visible in Figure 4, formed by the empty part 9 of the luminescent mark 5, represent, by way of example, what could be a production date.

In Figure 4, the sheets and layers comprising the band 1 can be seen. Specifically, the band 1 comprises a flexible outer plastic sheet 3 and a flexible plastic inner sheet 2, joined together by a layer of adherent material 6 interposed between they. On the one hand, the inner sheet 2 is intended to face the mesh bag and to be heat-sealed to the mesh bag and, on the other hand, the outer sheet 3 is intended to face the outside of the bag. The outer sheet 3 is made of plastic material transparent to visible light. For example, the outer sheet 3 is a 20 micron thick transparent oriented polypropylene sheet. The inner sheet 2 can be transparent or not. For example, it is a 20 micron thick polyethylene sheet. The printing ink layer 4 is translucent to visible light, so that when looking at the band 1 from the side of the outer sheet 3, the luminescent marks 5 are visible through said printing ink layer 4. The sheet Outer 3 presents, on its inner face 7, the printing ink layer 4 facing the inner sheet 2. As the outer sheet 3 is made of transparent material, when a user looks at the band 1 on the outer side, he can see the motifs and indications formed by the printing ink layer 4.

The luminescent marks 5 are arranged directly on the printing ink layer 4. That is, the luminescent marks 5 are separated from the inner face 7 of the outer sheet 3 by the printing ink layer 4. Furthermore, the material layer Adherent 6, which joins the inner sheet 2 with the outer sheet 3, is applied directly on the printing ink layer 4 and directly on the luminescent marks 5. The adhesive material layer 6 is for example a glue that is applied on the printing ink layer 4 and the luminescent marks 5. Although the luminescent marks 5 are covered by the sheets and / or layers, when the band 1 is irradiated With ultraviolet or infrared light, said light falls on them, making it possible for the luminescent marks to be detectable by a detector.

Band 1 is advantageously manufactured by a process consisting essentially of the following steps:

- providing the inner sheet 2 and the outer sheet 3, both with dimensions identical to those of the band 1 to be manufactured;

- printing on an inner face 7 of the outer sheet 3 patterns by direct application on said inner face 7 of a layer of printing ink 4; - printing on said printing ink layer 4 the luminescent marks 5, applying a luminescent ink directly on said printing ink layer 4;

- applying a glue over the entire surface of the outer sheet 3, covering said layer of printing ink 4 and said luminescent marks 5, to form the layer of adherent material 6;

- joining the inner sheet 2 to the outer sheet 3 through the layer of adhesive material 6.

The embodiments heretofore described represent non-limiting examples, so that one skilled in the art will understand that beyond the examples shown, within the scope of the invention multiple combinations between the claimed features are possible.

Claims (3)

1. - Flexible plastic material band (1), applicable for the manufacture of plastic material mesh bags in which said band (1) is heat-welded to the mesh, said band (1) comprising: - a plastic inner sheet (2), intended to face the bag and to be heat-sealed to said bag; - an outer plastic sheet (3), transparent to visible light, intended to face the outside of the bag; - a layer of printing ink (4) arranged between said inner sheet (2) and said outer sheet (3); - a layer of adherent material (6) arranged between said inner sheet (2) and said outer sheet (3) to join them; and - a plurality of luminescent marks (5), visible when said band (1) is irradiated with ultraviolet or infrared light, said luminescent marks (5) being arranged at regular intervals along said band (1); characterized in that said printing ink layer (4) is translucent to visible light and is applied directly to an inner face (7) of said outer sheet (3), facing said inner sheet (2), said luminescent marks ( 5) are arranged directly on said printing ink layer (4), separated from said inner face (7) of the outer sheet (3) by said printing ink layer (4), and said layer of adherent material (6 ) is applied directly on said printing ink layer (4) and directly on said luminescent marks (5), and because said luminescent marks (5) are not transparent to visible light. 2. - Band (1) according to claim 1, characterized in that said luminescent marks (5) are formed by a continuous zone (8) of luminescent material that surrounds an empty part (9) devoid of said luminescent material, so that said empty part (9) forms an alphanumeric indication. 3. - Band (1) according to any of claims 1 or 2, characterized in that said luminescent marks (5) form strips that extend transversely to said band (1).