The present invention relates to a continuous band of plastic-coated paper, which has been especially designed for the subsequent production of bags for horticultural produce and other similar products, by means of longitudinal heat-sealing or any other similar process of said band along its longitudinal seams, in order to convert it into a continuous tube, by means of parallel sealing and transverse cutting, to obtain independent, closed unitary bags.

The object of the invention is to obtain a continuous band that combines completely closed plastic-coated paper areas and mesh areas, and, when appropriate, perforations, in order to allow for the visibility and, especially, the aeration of the products contained therein, with maximum mechanical resistance of the bag, optimal protection of the products contained therein against light, greater bag printing capacity, a higher production rate, recyclable bags and a reduction in the thickness and weight of the plastic-coated paper, and, consequently, a lower cost.

For a long time, certain horticultural produce, such as oranges, potatoes, etc., have been marketed in plastic bags with a lattice structure, which allow for both aeration of the produce and visibility thereof. Sometimes, the production of these bags starts from a tubular mesh body closed on both ends after packaging of the product, optionally with one of said ends being equipped with handles that facilitate the transport thereof.

On other occasions, the process starts from a continuous laminar band, closed upon itself to configure the aforementioned tubular body, along a longitudinal heat-sealed line, after which the aforementioned process is repeated, such that filling of the bags is performed simultaneously with the unitary separation thereof.

The best solution adopted up to date belongs to the same applicant of this invention, and consists of a laminar plastic band with a number of openings, which are closed by a mesh material that is bound to the sheet by means of heat-sealing or a similar process.

Another solution is disclosed in patent document DE 29.506.855, which consists of a continuous band of plastic-coated paper for the production of bags formed from a continuous sheet of paper, synthetic material or a composite of these materials, with a width equal to that of said continuous band; a continuous sheet of plastic-coated paper where reinforcements of the same material as that of the continuous band, or another material, are placed on the seams or the periphery of the windows and, where appropriate, the perforations, said polyethylene reinforcements being bound to the sheet of plastic-coated paper by means of sealing with an adhesive material. The solution proposed in the present invention improves that disclosed in document DE 29.506.855 in various aspects, noteworthy amongst them the use of plastic-coated paper for the band, wherein the reinforcements are made of polyethylene and, moreover, are placed on the heat-sealed areas and the handle areas.

The continuous band proposed in the present invention represents a technological advance in this field and is based on the use of single continuous sheet of plastic-coated paper, whose width coincides with that of the band, such that said band is designed to close upon itself by means of heat-sealing along its longitudinal seams, in order to configure a continuous tube that may be fragmented into a plurality of sectors corresponding to respective bags, said continuous band having one or more windows and, where appropriate, perforations of equal or different size that may be closed with the aid of a mesh fragment, formally and dimensionally suitable for each window and fixed to the periphery thereof. The continuous band is made from a continuous sheet of plastic-coated paper on at least one of its sides, with a width equal to that of said continuous band; a continuous sheet of plastic-coated paper where, coinciding with each of the sectors thereof provided for the production of a bag, polyethylene reinforcements are placed in the areas proposed for the handles, the heat-sealings and the seams or the periphery of the windows and, where appropriate, the perforations, bound to the sheet of plastic-coated paper by means of heat-sealing or a similar process.

In a first preferred embodiment, at least one window is created coinciding with each of the sectors of the continuous sheet of plastic-coated paper, which is closed with the aid of a mesh fragment, formally and dimensionally suitable for said window and fixed to the periphery of said window by means of heat-sealing.

The sheet of plastic-coated paper may be plasticised on both sides.

In a second preferred embodiment, when a single window with its corresponding mesh is created in each sector of the continuous sheet of plastic-coated paper, said window is centred with respect to the longitudinal axis of the continuous sheet of plastic-coated paper, and small perforations, without a mesh, are created on both sides thereof.

Optionally, the mesh that closes the window is a continuous strip of mesh that runs longitudinally along the continuous plastic sheet.

On the other hand, in addition to the polyethylene reinforcements placed on the handle areas, a second polyethylene reinforcement fixed to the polyethylene reinforcement may be placed by means of heat-sealing or any other means, with the special feature that the second reinforcement is fixed to the polyethylene reinforcement on the surface of the latter, unrelated to the U-shaped strip delimited by a punched line that affects both the polyethylene reinforcement and the sheet of plastic-coated paper, the strip forming a handle designed to emerge through the mouth of the body of the bag.

The punched lines that determine the U-shaped strip may be pre-cut or sliding lines which keep said U-shaped strip in a co-planar position with respect to the rest of the polyethylene reinforcement and the sheet of plastic-coated paper.

Moreover, each sector of the band designed to produce a bag incorporates polyethylene reinforcements that coincide with two points of the bag mouth, diametrically opposed to one another, such that the base incorporates two handles that emerge from said bag mouth, also diametrically opposed to one another.

Using the continuous band of plastic-coated paper of the preceding description, we obtain a product with all the advantages of continuous plastic bands, but at a lower cost and with the possibility of recycling a part of the materials used in the production thereof, which makes it less harmful to the environment.

fig. 1

shows the sheet of plastic-coated paper with the fixed polyethylene reinforcements;

fig. 2

shows an exploded view of the sheet with the windows, the punched perforations, the mesh fragments and the handles;

fig. 3

shows the continuous band of plastic-coated paper with the mesh fragments and the handles placed at their final position;

fig. 4

shows various bag models that may be obtained.

1.

Continuous band of plastic-coated paper

2.

Sheet of plastic-coated paper

3.

Polyethylene reinforcement

4.

Central window

5.

Lateral window

6.

Mesh fragment

8.

Handle

9.

Bag

In light of the figures incorporated into the present specification, and especially Figures 1-3, it may be observed that the continuous band of plastic-coated paper for the production of bags is formed from a continuous sheet of plastic-coated paper; in this preferred embodiment, the paper is plasticised on both sides, and its width coincides with the width of the band of plastic-coated paper and, therefore, is twice as wide as the bag to be obtained; along the sheet of plastic-coated paper, groups of windows are placed, obtained by means of punching, of different sizes and shapes, with at least one window centred on what will become the front of the bag, and, in this embodiment, another pair of longer windows are placed at the sides of the central window. The windows are closed by formally and dimensionally suitable mesh fragments. Optionally, groups of perforations that are not closed by mesh fragments may be placed, in order to increase aeration of the packaged products.

In order to increase the mechanical resistance of the bag in the areas designed to be heat-sealed, the handles and the periphery of the windows, polyethylene reinforcements are placed in said areas which are bound to the continuous sheet by means of heat-sealing or any other similar process. In this embodiment, the windows are created after sealing the mesh fragments.

Figure 4 shows various types of bags that may be obtained from the continuous band of plastic-coated paper of the present invention.